arc welding by: john templeton. objectives identify and explain safety practices and procedures as...

Arc WeldingArc Welding

By: John TempletonBy: John Templeton

ObjectivesObjectives

Identify and explain safety practices and Identify and explain safety practices and procedures as related to electric and oxy-procedures as related to electric and oxy-fuel weldingfuel welding

Identify equipment used in SMAW weldingIdentify equipment used in SMAW welding

Explain the SMAW processExplain the SMAW process

Identify the 2 types of welding current and Identify the 2 types of welding current and machinesmachines

Arc WeldingArc Welding

The process of fusing two or more pieces of The process of fusing two or more pieces of metal together by using the heat produced from metal together by using the heat produced from an electric arc welding machine.an electric arc welding machine.

Otherwise known as SMAW (shielded metal arc Otherwise known as SMAW (shielded metal arc welding)welding)– The electrode produces a gas which shields the arc The electrode produces a gas which shields the arc

from the atmosphere as the electrode melts.from the atmosphere as the electrode melts.

SMAW AdvantagesSMAW Advantages

Scrap metal can used make repairsScrap metal can used make repairs

Repairs can be made quickly before a problem Repairs can be made quickly before a problem becomes severebecomes severe

Metal repair and construction can be Metal repair and construction can be accomplished more economicallyaccomplished more economically

Arc welders can be used to accomplish jobs like Arc welders can be used to accomplish jobs like cutting, piercing, gouging and bevelingcutting, piercing, gouging and beveling

Welding EquipmentWelding Equipment

Welding hoodWelding hood

Welding glovesWelding gloves

ElectrodesElectrodes

Welding machineWelding machine

Chipping hammerChipping hammer

Wire brushWire brush

Welding EquipmentWelding Equipment

Welding leadsWelding leads

Electrode holderElectrode holder

Ground clampGround clamp

Alternating Current WeldingAlternating Current Welding

AC (alternating AC (alternating current)current)– Most commonMost common– 180 Ampere or 225 180 Ampere or 225

Ampere between 220-Ampere between 220-240 volts240 volts

– Can handle most Can handle most agriculture and agriculture and construction jobsconstruction jobs

– Alternating flow of Alternating flow of electronselectrons

SMAWSMAW

Direct Current WeldingDirect Current Welding

DC (direct current)DC (direct current)– Can produce direct current of both straight Can produce direct current of both straight

(negative) and reverse (positive) polarity. (negative) and reverse (positive) polarity.

– Polarity is the direction in which the current Polarity is the direction in which the current flows across the arc.flows across the arc.

– Makes a continuous flow of electronsMakes a continuous flow of electrons

Straight/Reverse PolarityStraight/Reverse Polarity

Straight Polarity (DC-)Straight Polarity (DC-)– Work is positive and Work is positive and

electrode is negativeelectrode is negative– Used to weld thinner Used to weld thinner

metalsmetals– Shallow penetrationShallow penetration

Reverse Polarity (DC+)Reverse Polarity (DC+)– Work is negative and Work is negative and

electrode is positiveelectrode is positive– Used to weld thicker metalsUsed to weld thicker metals– Deeper penetration Deeper penetration

Types of Welding MachinesTypes of Welding Machines

AC machineAC machine– Only works on Only works on

alternating current (+-)alternating current (+-)


AC/DCAC/DC– Can run on three different types of currentCan run on three different types of current

AlternatingAlternatingDirect current + (reverse polarity)Direct current + (reverse polarity)Direct current – (straight polarity)Direct current – (straight polarity)

This machine will have a rectifier switch which This machine will have a rectifier switch which will allow it to switch between the threewill allow it to switch between the three

Or the leads will need to be placed in certain Or the leads will need to be placed in certain parts of the machine.parts of the machine.


AC/DC MachinesAC/DC Machines– Are capable of Are capable of

handling most handling most agriculture and agriculture and construction.construction.

– Are the most popular.Are the most popular.

– Allow the operator to Allow the operator to weld metal of all weld metal of all thickness.thickness.


Machines can either Machines can either be gasoline engine be gasoline engine driven or they can be driven or they can be powered be powered be electricity.electricity.

Duty CycleDuty Cycle

Tells the operator how long his machine Tells the operator how long his machine can operate without causing damage to can operate without causing damage to the machine.the machine.

It is how long a machine can run in ten It is how long a machine can run in ten minute intervals, and is measured by a minute intervals, and is measured by a percentage.percentage.

Duty CycleDuty Cycle

If a machine has a duty cycle of 25%, for If a machine has a duty cycle of 25%, for every ten minutes the machine is operated every ten minutes the machine is operated you can only weld for 2.5 minutes.you can only weld for 2.5 minutes.

The remaining 7.5 minutes must be spent The remaining 7.5 minutes must be spent letting the machine idle. letting the machine idle.


All major manufacturers of welding All major manufacturers of welding electrodes use the American Welding electrodes use the American Welding Society (AWS) code of specifications. Society (AWS) code of specifications.

Each company makes basically the same Each company makes basically the same quality which is established by the AWS. quality which is established by the AWS.


Electrodes are classified according to type Electrodes are classified according to type of coating, composition of the weld metal of coating, composition of the weld metal and operating characteristics.and operating characteristics.

The numbering system is started with “E” The numbering system is started with “E” for electrode and then followed by a four for electrode and then followed by a four digit numberdigit number


Each number in the four number sequence has a Each number in the four number sequence has a specific meaning.specific meaning.

60XX = Tensile Strength in pounds (X 1,000)60XX = Tensile Strength in pounds (X 1,000)60,000 lbs per square inch60,000 lbs per square inch

XX1X = Welding PositionXX1X = Welding Position1 =All 1 =All 2 = Flat and Horizontal 2 = Flat and Horizontal 3 = 3 = FlatFlat

XXX1 = PolarityXXX1 = Polarity1,3,4,8=AC or DC1,3,4,8=AC or DC Reverse Reverse 2 = AC or DC straight 2 = AC or DC straight 0 = DC Reverse0 = DC Reverse


What is the classification of an E 7018? What is the classification of an E 7018? – EE

– 7070

– 11

– 88

Electrode DiameterElectrode Diameter

Electrodes are also measured by their diameter Electrodes are also measured by their diameter (the diameter of the electrode without including (the diameter of the electrode without including the flux.the flux.

The diameter is measured in thirty-seconds of The diameter is measured in thirty-seconds of an inch.an inch.

Always use an electrode ½ the size of you base Always use an electrode ½ the size of you base metalmetal– What does this mean?What does this mean?


What diameter electrode should you use if What diameter electrode should you use if your base metal is ½ in thick?your base metal is ½ in thick?

1/8 inch?1/8 inch?

¼ inch?¼ inch?


When selecting an electrode you need to When selecting an electrode you need to consider the following:consider the following:

– How thick is your base metal?How thick is your base metal?– What condition is your metal in?What condition is your metal in?– What type of machine do you have access to?What type of machine do you have access to?– Welding position?Welding position?

Welding SafetyWelding Safety

Electrical shockElectrical shock

– Make sure the machine is grounded.Make sure the machine is grounded.– Make sure the cables are not cut or frayed.Make sure the cables are not cut or frayed.– Do not stand in wet surfaces.Do not stand in wet surfaces.– Wear leather gloves.Wear leather gloves.– Wear rubber-soled shoesWear rubber-soled shoes

Radiant EnergyRadiant Energy

Radiant Energy can cause burnRadiant Energy can cause burn

– Make sure you helmet is in good repair and Make sure you helmet is in good repair and lenses are not cracked.lenses are not cracked.

– Make sure all skin is covered with cotton Make sure all skin is covered with cotton material material

– Say cover before welding, so that everyone Say cover before welding, so that everyone can protect themselves from radiant energycan protect themselves from radiant energy

Eye ProtectionEye Protection

Make sure you are welding with a shade of Make sure you are welding with a shade of 12-14 lens12-14 lens

Make sure your helmet has a Z87 clear Make sure your helmet has a Z87 clear lens with a shaded 12-14 lens on top.lens with a shaded 12-14 lens on top.

VentilationVentilation

Make sure you are Make sure you are welding in a well welding in a well ventilated areaventilated area

If you become sick do If you become sick do not continue and drink not continue and drink milk.milk.

Use fans to blow out Use fans to blow out smokesmoke

General SafetyGeneral Safety

Keep work area clean and free from Keep work area clean and free from hazards.hazards.

– Welding leadsWelding leads– FlammablesFlammables– Cover eyes while chipping slagCover eyes while chipping slag

What to do and what not to doWhat to do and what not to do

ReviewReview

What are the types of welding current?What are the types of welding current?

What are the types of welding machines?What are the types of welding machines?

Describe proper ventilation when welding.Describe proper ventilation when welding.

arc welding by: john templeton. objectives identify and explain safety practices and procedures as...

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