GMAW FundamentalsGMAW Fundamentals

Gas Metal Arc Welding

Metal Inert Gas

SafetySafety

1048708

Electrocution hazard1048708 Skin burns from flying metal1048708 Skin burns from direct light from arc1048708 Skin burns from indirect light from arc1048708 Cotton clothing and leather gloves1048708 Helmet to protect eyes from light1048708 Safety glasses when chipping slag

1048708 Ventilation to remove dangerous fumes1048708 Do not weld near water1048708 Do not weld near combustible materials1048708 Keep welding cables and jobs free grease1048708 Protect bystanders from arc rays

IntroductionIntroduction

GMAW is defined as arc welding using a continuously fed consumable electrode and a shielding gas

GMAW is also known as MIG (Metal Inert Gas)

Produces high-quality weldsYields high productivity

AdvantagesAdvantages

Large gaps filled or bridged easilyWelding can be done in all positionsNo slag removal requiredHigh welding speedsHigh weld qualityLess distortion of work piece

DisadvantagesDisadvantages

Hard to reach locations are less easily welded because of bulky torch and cables

Wind or air drafts may compromise gas shielding Reactive metals (ie titanium) may need special

shielding provisions High heat may be uncomfortable to welders Correct parameter selection learning needs

dedicated training Equipment is more complex and expensive than

that of alternative processes

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

SafetySafety

1048708

Electrocution hazard1048708 Skin burns from flying metal1048708 Skin burns from direct light from arc1048708 Skin burns from indirect light from arc1048708 Cotton clothing and leather gloves1048708 Helmet to protect eyes from light1048708 Safety glasses when chipping slag

1048708 Ventilation to remove dangerous fumes1048708 Do not weld near water1048708 Do not weld near combustible materials1048708 Keep welding cables and jobs free grease1048708 Protect bystanders from arc rays

IntroductionIntroduction

GMAW is defined as arc welding using a continuously fed consumable electrode and a shielding gas

GMAW is also known as MIG (Metal Inert Gas)

Produces high-quality weldsYields high productivity

AdvantagesAdvantages

Large gaps filled or bridged easilyWelding can be done in all positionsNo slag removal requiredHigh welding speedsHigh weld qualityLess distortion of work piece

DisadvantagesDisadvantages

Hard to reach locations are less easily welded because of bulky torch and cables

Wind or air drafts may compromise gas shielding Reactive metals (ie titanium) may need special

shielding provisions High heat may be uncomfortable to welders Correct parameter selection learning needs

dedicated training Equipment is more complex and expensive than

that of alternative processes

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

IntroductionIntroduction

GMAW is defined as arc welding using a continuously fed consumable electrode and a shielding gas

GMAW is also known as MIG (Metal Inert Gas)

Produces high-quality weldsYields high productivity

AdvantagesAdvantages

Large gaps filled or bridged easilyWelding can be done in all positionsNo slag removal requiredHigh welding speedsHigh weld qualityLess distortion of work piece

DisadvantagesDisadvantages

Hard to reach locations are less easily welded because of bulky torch and cables

Wind or air drafts may compromise gas shielding Reactive metals (ie titanium) may need special

shielding provisions High heat may be uncomfortable to welders Correct parameter selection learning needs

dedicated training Equipment is more complex and expensive than

that of alternative processes

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

AdvantagesAdvantages

Large gaps filled or bridged easilyWelding can be done in all positionsNo slag removal requiredHigh welding speedsHigh weld qualityLess distortion of work piece

DisadvantagesDisadvantages

Hard to reach locations are less easily welded because of bulky torch and cables

Wind or air drafts may compromise gas shielding Reactive metals (ie titanium) may need special

shielding provisions High heat may be uncomfortable to welders Correct parameter selection learning needs

dedicated training Equipment is more complex and expensive than

that of alternative processes

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

DisadvantagesDisadvantages

Hard to reach locations are less easily welded because of bulky torch and cables

Wind or air drafts may compromise gas shielding Reactive metals (ie titanium) may need special

shielding provisions High heat may be uncomfortable to welders Correct parameter selection learning needs

dedicated training Equipment is more complex and expensive than

that of alternative processes

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Several tips must be consider in Several tips must be consider in selecting mode of transferselecting mode of transfer

Type intensity and polarity of welding current

Electrode size Electrode composition Electrode extension Shielding gas mix composition

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three distinctive process techniques

1 Short Circuit (Short Arc)

2 Globular Transfer

3 Spray Arc Transfer

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Modes of GMAW TransferModes of GMAW Transfer

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Short Circuit (Short Arc)Short Circuit (Short Arc)

Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position as

well as thick materials in vertical and overhead positions

Metal transfer occurs when an electrical short circuit is established

this cycle can repeat itself between 20 and as much as 250 times per second

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Short CircuitShort CircuitA - Electrode is short circuited to base metal No arc and current is flowing through electrode wire and base metalB - Resistance increases in electrode wire causing it to heat melt and ldquoneck downrdquoC - Electrode wire separates from weld puddle creating an arc Small portion of electrode wireis deposited which forms a weld puddleD - Arc length and load voltage are at maximum Heat of arc is flattening the puddle and increasingthe diameter tip of electrodeE - Wire feed speed overcomes heat of arc and wire approaches base metal againF - Arc is off and the short circuit cycle starts again

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

AdvantagesAdvantages

All-position capability including flat horizontal vertical-up vertical-down and overhead

Handles poor fit-up extremely well and is capable of root pass work on pipe applications

Lower heat input reduces weldment distortion Higher operator appeal and ease of use Higher electrode efficiencies 93 or more

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

LimitationsLimitations

Restricted to sheet metal thickness range and open roots of groove joints on heavier sections of base material

Poor welding procedure control can result in incomplete fusion Cold lap and cold shut are additional terms that serve to describe incomplete fusion defects

Poor procedure control can result in excessive spatter and will increase weldment cleanup cost

To prevent the loss of shielding gas to the wind welding outdoors may require the use of a windscreen(s)

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Globular TransferGlobular Transfer

Welding current and wire speed are increased above maximum for short arc

Droplets of metal have a greater diameter than the wire being used

Spatter present Welding is most effectively done in the flat

position when using globular transfer

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Globular transfer is often a high voltage high amperage high wire feed speed transfer and is the result of using CO2 shielding gas (or 75 AR-25 CO2) with parameters higher than the short-circuiting range

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

AdvantagesAdvantages

Uses inexpensive CO2 shielding gas but is frequently used with argonCO2 blends

Is capable of making welds at very high travel speeds

Inexpensive solid or metal-cored electrodesWelding equipment is inexpensive

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

LimitationsLimitations

Higher spatter levels result in costly cleanup Prone to cold lap or cold shut incomplete fusion defects

which results in costly repairs Weld bead shape is convex and welds exhibit poor

wetting at the toes High spatter level reduces electrode efficiency to a range

of 87 ndash 93 Less desirable weld appearance than spray arc transfer Welding is limited to flat positions and horizontally fillet

welds Welding is limited to metal 18 inch (3 mm) or thicker

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Spray Arc TransferSpray Arc Transfer

Occurs when the current and voltage settings are increased higher than that used for Globular Transfer

Used on thick sections of base material best suited for flat position due to large weld puddle

Spatter is minimal to none Uses 5 to 10 co2 mix with argon or oxygen

gtForms very small droplets of metalgtVery good stabilitygtVery little spatter

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Spray arc transfer ldquospraysrdquo a streamof tiny molten droplets across thearc from the electrode wire to thebase metalSpray arc transfer uses relativelyhigh voltage wire feed speed andamperage values compared to shortcircuit transfer

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

AdvantagesAdvantages

High deposition rates High electrode efficiency of 98 or more Employs a wide range of filler metal types in an

equally wide range of electrode diameters Excellent weld bead appearance High operator appeal and ease of use Requires little post weld cleanup Absence of weld spatter Excellent weld fusion Lends itself to semiautomatic robotic and hard

automation applications

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

LimitationsLimitations

Restricted to the flat and horizontal welding positions

Welding fume generation is higher The higher-radiated heat and the generation of a

very bright arc require extra welder and bystander protection

The use of axial spray transfer outdoors requires the use of a windscreen(s)

The shielding used to support axial spray transfer costs more than 100 CO2

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Pulse Spray Transfer Pulse Spray Transfer

GMAW-P was developed for two demanding reasons control of weld spatter and the elimination of incomplete fusion defects common to globular and short-circuiting transfer

The welding current alternates between a peak current and a lower background current

This faster-freezing weld puddle is what allows the pulsed-spray transfer to be used fort thinner metals

better control on out-of-position work allows for larger wire sizes to be used on varied metal

thicknesses

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

In pulse spray transfer (GMAW-P) the welding power sourcersquos pulse control pulses the welding output withhigh peak currents (amperage) which are set at levels which will cause the transfer to go into a spray The background current (amperage) is set at a level that will maintain the arcbut is too low for any metal transfer to occur

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Pulsed arc transferPulsed arc transfer

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

AdvantagesAdvantages Absent or very low levels of spatter More resistant to lack of fusion defects than other modes of

GMAW metal transfer Excellent weld bead appearance and offers an engineered

solution for the control of weld fume generation Reduced levels of heat induced distortion and tendency for arc

blow Ability to weld out-of-position and handles poor fit-up When compared to FCAW SMAW and GMAW-S pulsed

spray transfer provides a low cost high-electrode efficiency of 98

Lends itself to robotic and hard automation applications Is combined for use with Tandem GMAW or other multiple arc

scenarios Capable of arc travel speeds greater than 50 inches per minute

(12 Mmin)

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

LimitationsLimitationsEquipment to support the process is more

expensive than traditional systemsBlends of argon based shielding gas are

more expensive than carbon dioxideHigher arc energy requires the use of

additional safety protection for welders and bystanders

Adds complexity to weldingRequires the use of windscreens outdoors

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are

1) Welding torch and accessories

2) Welding control amp Wire feed motor

3) Power Source

GMAW equipment can be used either manually or automatically

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

GMAW Schematic DiagramGMAW Schematic Diagram

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

WIRE CONTROLamp

WIRE FEED MOTOR

POWER SOURCE

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Welding Torch amp AccessoriesWelding Torch amp Accessories

The welding torch guides the wire and shielding gas to the weld zone

Brings welding power to the wire alsoMajor componentsparts of the torch are the

contact tip shielding gas nozzle gas diffuser and the wire conduit

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Others types of torchOthers types of torch

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Welding Control amp Wire Welding Control amp Wire Feed MotorFeed Motor

Welding control amp Wire feed motor are combined into one unit

Main function is to pull the wire from the spool and feed it to the arc

Controls wire feed speed and regulates the starting and stopping of wire feed

Wire feed speed controls Amperage

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Types of Wire Feed MotorTypes of Wire Feed Motor

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Types of WFM RollerTypes of WFM Roller

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Types of Wire FeederTypes of Wire Feeder

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

WIRE FEEDER

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Power SourcePower Source

Almost all GMAW is done with reverse polarity also known as DCEP

Positive (+) lead is connected to the torchNegative (-) lead is connected to the work

pieceProvides a relatively consistent voltage to the

arcArc Voltage is the voltage between the end of

the wire and the work piece

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Contact Tip To Work DistanceContact Tip To Work Distance

In constant current the CTWD (contact tip to work distance) determines the arc length

As the CTWD increases the arc length increases and as the

CTWD decreases the arc length decreases This presented a

problem for semiautomatic welding because it is difficult to

maintain the same CTWD To compensate for this problem an arc voltage controlled wire

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Constant voltage power source designs provide a specific arc voltage for a given pre-selected wire feed speed The volt-amp curve or slope is comparatively flat As the CTWD increases with these types of power sources there is a decrease in the welding current As the CTWD decreases there is an increase in the welding current The arc in this case becomes a series circuit and the CTWD provides resistance to current In either scenario the voltage remains the same and the arc length remains the same

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Shielding GasesShielding Gases

Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere

Gas can be Inert Reactive or Mixtures of both

Gas flow rate is between 25-35 CFHArgon Helium and Carbon Dioxide are the

main three gases used in GMAW

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Properties of GasesProperties of Gases

Affect the performance of the welding process include

1) Thermal properties at elevated temperatures 2) Chemical reaction of the gas with the various

elements in the base plate and welding wire 3) Effect of each gas on the mode of metal

transfer

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Types of shielding gasesTypes of shielding gases

Inert Gas

1 Argon

2 Helium

3 Ar + HeActive Gas

1 Carbon Dioxide

2 Inert gas + any type of active gas

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Argon is an inert gas which is used both singularly and in combination with other gases to achieve desired arc characteristics for the welding of both ferrous and non-ferrous metals

Carbon Dioxide Pure carbon dioxide is not an inert gas because the heat of the arc breaks down the CO2 into carbon monoxide and free oxygen This oxygen will combine with elements transferring across the arc to form oxides which are released from the weld puddle in the form of slag and scale

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Helium is an inert gas which is used on weld applications requiring higher heat input for improved bead wetting deeper penetration and higher travel speed In GMAW it does not produce as stable an arc as argon Compared to argon helium has a higher thermal conductivity and voltage gradient

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Filler WireFiller Wire

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Wire ChemistriesWire Chemistries

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

GMAW Operation techniquesGMAW Operation techniques

To setting WFS (Wire Feed Speed)

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Voltage-bead ChangeVoltage-bead Change

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Electrode Stick-outElectrode Stick-out

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

ESO SettingESO Setting

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

EOSEOS

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Gun angles and techniquesGun angles and techniques

Direction of TravelDirection of Travel

THANK YOU

Direction of TravelDirection of Travel

THANK YOU

THANK YOU