shielded metal arc welding

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Copyright Copyright 2004 Lincoln Global Inc. 2004 Lincoln Global Inc.

Shielded Metal Arc WeldingShielded Metal Arc Welding

Part IIPart IIA.A. General Information General Information

B.B. PolarityPolarity

C.C. Set UpSet Up

D.D. Striking an ArcStriking an Arc

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An arc welding process with an arc between a coveredAn arc welding process with an arc between a covered

electrode and the weld pool. The process is used withelectrode and the weld pool. The process is used with

shielding from the decomposition of the electrodeshielding from the decomposition of the electrode

covering, covering,

without the without the

application of application of

pressure pressure

and with filler and with filler

metal from metal from

the electrode. the electrode.

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Principles of the SMAW ProcessPrinciples of the SMAW Process

• Electric Arc Between Electrode & Work, Melts the Electric Arc Between Electrode & Work, Melts the Electrode & Fuses the JointElectrode & Fuses the Joint

• Weld Metal & Slag FormWeld Metal & Slag Form• Slag is Slag is

Lighter than the Lighter than the Molten Metal & Molten Metal & Rises to the Rises to the Top Top

• AC or DC AC or DC PolarityPolarity

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DCEN (Striaght) PolarityDCEN (Striaght) Polarity

• DC -DC -

• Heat Concentrated at Heat Concentrated at ElectrodeElectrode

• Lower PenetrationLower Penetration

• Increased Deposition Increased Deposition Rates Rates

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DCEN

Direct Current Electrode NegativeDirect Current Electrode Negative

Direct Current Electrode Negative (DCEN):Direct Current Electrode Negative (DCEN):TheThe

arrangement of direct current arc weldingarrangement of direct current arc welding

cables/leads in which the electrode is the cables/leads in which the electrode is the

negative pole and the workpiece is the positive polenegative pole and the workpiece is the positive pole

of the welding arc.of the welding arc.

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DCEP (Reverse) PolarityDCEP (Reverse) Polarity

• DC +DC +

• Heat Concentrated at Heat Concentrated at WorkpieceWorkpiece

• Forceful, Digging ArcForceful, Digging Arc

• Medium to Deep Medium to Deep PenetrationPenetration

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DCEP

Direct Current Electrode PositiveDirect Current Electrode Positive

Direct Current Electrode Positive (DCEP):Direct Current Electrode Positive (DCEP): TheThe

arrangement of direct current arc weldingarrangement of direct current arc welding

cables/leads in which the electrode is the cables/leads in which the electrode is the

positive pole and the workpiece is the negative polepositive pole and the workpiece is the negative pole

of the welding arc.of the welding arc.

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AC PolarityAC Polarity

• Medium PenetrationMedium Penetration

• Medium Travel SpeedsMedium Travel Speeds

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Alternating CurrentAlternating Current

Alternating Current (AC):Alternating Current (AC): A current which reversesA current which reverses

at regularly recurring intervals of time (every 1/100 orat regularly recurring intervals of time (every 1/100 or

1/120 of a second) and which has alternately positive1/120 of a second) and which has alternately positive

and negative values. Modern power systems normallyand negative values. Modern power systems normally

generate a sinusoidal alternating current of either 50generate a sinusoidal alternating current of either 50

or 60 Hertz (Hz). or 60 Hertz (Hz).

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Electrode CableElectrode CableElectrode JawElectrode Jaw

Upper Jaw InsulationUpper Jaw Insulation

Lower JawLower Jaw

Arm InsulationArm Insulation

Cable CouplingCable CouplingGrip HandleGrip HandleConnector PinConnector Pin

Lower Jaw InsulationLower Jaw Insulation

Lincoln Equipment SetupLincoln Equipment Setup

Magnum 300 Amp Electrode HolderMagnum 300 Amp Electrode Holder

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GC 300GC 300

Tighten Lug To Tighten Lug To Ground ClampGround Clamp

Secure Lug to CableSecure Lug to Cable

SMAW SMAW - Lincoln Equipment Setup- Lincoln Equipment Setup

Magnum 300 Amp Work ClampMagnum 300 Amp Work Clamp

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Lincoln Equipment SetupLincoln Equipment Setup

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• Known as Stick or Manual WeldingKnown as Stick or Manual Welding• Uses CC Power SourceUses CC Power Source• Versatile ProcessVersatile Process• All PolaritiesAll Polarities• Match Electrode Match Electrode

with Power with Power Source, Source, Base Metal, Base Metal, and Joint Designand Joint Design

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The SMAW Process BasicsThe SMAW Process Basics

Arc

Original Surface Of Base Metal

Reinforcement-Build-up of Weld Metal

Slag

Molten Weld Metal

Protective Gas from Electrode Coating

Electrode Wire(Filler Metal)

Electrode Coating (Flux)

Metal Droplets

Penetration

Arc

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Approximate Electrode Amperage Settings

Fast Freeze Fill Freeze Fast Fill Low HydrogenE6010 - E6011 E6013 - E7014 E7024 - E7028 E7018

Diameter of Current Setting Current Setting Current Setting Current SettingElectrode

Inches(Millimeters) Amperes Amperes Amperes Amperes

3/32 in (2.4 mm) 40 - 90 75 - 105 85 - 155 70 - 140 1/8 in (3.2 mm) 75 - 130 100 - 165 100 - 175 90 - 1855/32 in (4.0 mm) 80 - 160 135 - 225 160 - 270 140 - 2303/16 in (4.8 mm) 110 - 225 185 - 280 220 - 330 210 - 3007/32 in (5.6 mm) 200 - 260 235 - 340 270 - 410 230 - 380 1/4 in (6.4 mm) 220 - 325 260 - 425 315 - 520 290 - 440

Approximate Amperage SettingsApproximate Amperage Settings

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Starting The ArcStarting The Arc

Scratch Start Strike (Tap) Start

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1. Strike Arc Here

2. Move Electrode to Crown of Crater

3. Resume Travel Forward

Restarting Interrupted BeadRestarting Interrupted Bead

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Bead InitiationBead Initiation

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Bead FormationBead Formation

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Electrode MovementElectrode Movement

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Electrode MovementsElectrode Movements

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Bead TerminationBead Termination

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Sample Beads For Quality WeldingSample Beads For Quality Welding

shielded metal arc welding

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