gmaw.bekasi 23 agt_2

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LAS MAG/GMAWLAS MAG/GMAW DISAMPAIKAN OLEH :DISAMPAIKAN OLEH :

BAMBANG PRAWIROBAMBANG PRAWIROSUBAGSONOSUBAGSONOBAMBANG DWI WAHYUDIBAMBANG DWI WAHYUDI

UNIVERSITAS SEBELAS MARETUNIVERSITAS SEBELAS MARETSOLOSOLO

ObjectivesObjectives

Gambaran umum pengoperasian GMAWGambaran umum pengoperasian GMAW Gambaran umum cacat dalam pengelasan Gambaran umum cacat dalam pengelasan

GMAWGMAW Mendemonstrasikan, menggunakan, dan Mendemonstrasikan, menggunakan, dan

troubleshooting peralatantroubleshooting peralatan Mendemonstrasikan teknik pengelasan Mendemonstrasikan teknik pengelasan Mengelas pelat baja lunak pada berbagai Mengelas pelat baja lunak pada berbagai

posisi posisi

IntroductionIntroduction

GMAW didefinisikan sebagai busur GMAW didefinisikan sebagai busur cahaya menggunakan satu elektroda yang cahaya menggunakan satu elektroda yang dikonsumsi secara kontinyu, bersamaan dikonsumsi secara kontinyu, bersamaan gas pelindung.gas pelindung.

GMAW dikenal juga sebagai MIG/MAG .GMAW dikenal juga sebagai MIG/MAG . Hasil pengelasan kualitasnya lebih tinggiHasil pengelasan kualitasnya lebih tinggi Hasilkan produktivitas tinggiHasilkan produktivitas tinggi

KEUNTUNGAN KEUNTUNGAN Mudah dalam pengisian celah Mudah dalam pengisian celah

atau gap atau gap Pengelasan dapat dilakukan dalam Pengelasan dapat dilakukan dalam

semua posisisemua posisiTidak ada / sedikit slag atau terakTidak ada / sedikit slag atau terakKecepatan las yang TinggiKecepatan las yang TinggiKualitas tinngiKualitas tinngiLebih kecil distorsi Lebih kecil distorsi

Types of Metal TransferTypes of Metal Transfer

The basic GMAW process includes three The basic GMAW process includes three distinctive process techniques:distinctive process techniques:

1.1. Short Circuit (Short Arc)Short Circuit (Short Arc)2.2. Globular TransferGlobular Transfer3.3. Spray Arc TransferSpray Arc Transfer

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

Beroperasi pada tegangan dan arus rendahBeroperasi pada tegangan dan arus rendah Pembekuan-cepat . kubah Kecil (mengelas)Pembekuan-cepat . kubah Kecil (mengelas) Cocok dalam pengelasan bahan tipis pada Cocok dalam pengelasan bahan tipis pada

posisi apapun, demikian pula bahan tebal posisi apapun, demikian pula bahan tebal pada posisi vertikal dan posisi 'overhead’pada posisi vertikal dan posisi 'overhead’

Transfer Logam terjadi ketika hubungan Transfer Logam terjadi ketika hubungan singkat listrik stabilsingkat listrik stabil

Globular TransferGlobular Transfer Arus dan kecepatan kawat las terjadi maksimum Arus dan kecepatan kawat las terjadi maksimum

diatas short arc .diatas short arc . Cairan logam terjadi lebih besar dari diameter Cairan logam terjadi lebih besar dari diameter

kawat yang sedang digunakankawat yang sedang digunakan Spater terjadi saat ini pengelasan lebih banyakSpater terjadi saat ini pengelasan lebih banyak Cocok untuk Pengelasan terjadi secara efektif Cocok untuk Pengelasan terjadi secara efektif

bila dilakukan pada posisi flat ketika bila dilakukan pada posisi flat ketika menggunakan transfer berbentuk bulatmenggunakan transfer berbentuk bulat

Spray Arc TransferSpray Arc Transfer

Terjadi ketika arus dan setting tegangan Terjadi ketika arus dan setting tegangan yang digunakan lebih tinggi dari Globular yang digunakan lebih tinggi dari Globular TransferTransfer

Cocok Digunakan pada material tebal, Cocok Digunakan pada material tebal, pada semua bawah tanganpada semua bawah tangan

Spater / Percikan sedikit Spater / Percikan sedikit

Manual GMAW EquipmentManual GMAW Equipment

Three major elements are :Three major elements are :1.) Welding torch and accessories1.) Welding torch and accessories2.) Welding control & Wire feed motor2.) Welding control & Wire feed motor3.) Power Source3.) Power Source

GMAW equipment can be used either GMAW equipment can be used either manually or automaticallymanually or automatically

WIRE CONTROL&

WIRE FEED MOTOR

POWER SOURCE

Welding Torch & AccessoriesWelding Torch & Accessories

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

Brings welding power to the wire alsoBrings welding power to the wire also Major components/parts of the torch are Major components/parts of the torch are

the contact tip, shielding gas nozzle, gas the contact tip, shielding gas nozzle, gas diffuser, and the wire conduitdiffuser, and the wire conduit

TRIGGER

INSTALLED

COMPONENTS

NOZZLE

CONTACT TIP

GAS DIFFUSER

Welding Control & Wire Welding Control & Wire Feed MotorFeed Motor

Welding control & Wire feed motor are Welding control & Wire feed motor are combined into one unitcombined into one unit

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

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

Wire feed speed controls AmperageWire feed speed controls Amperage

WIRE FEEDER

Power SourcePower Source Almost all GMAW is done with reverse Almost all GMAW is done with reverse

polarity also known as DCEPpolarity also known as DCEP Positive (+) lead is connected to the torchPositive (+) lead is connected to the torch Negative (-) lead is connected to the work Negative (-) lead is connected to the work

piecepiece Provides a relatively consistent voltage to Provides a relatively consistent voltage to

the arcthe arc Arc Voltage is the voltage between the end Arc Voltage is the voltage between the end

of the wire and the work pieceof the wire and the work piece

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Direct Current Electrode Direct Current Electrode Positive (DCEP)Positive (DCEP)

Generally used for gas metal arc weldingGenerally used for gas metal arc welding Provides maximum heat input into work allowing Provides maximum heat input into work allowing

relatively deep penetration to take placerelatively deep penetration to take place Assists in removal of oxides from plateAssists in removal of oxides from plate Low current values produce globular transfer of metal Low current values produce globular transfer of metal

from electrodefrom electrode On carbon steel shielding gas must contain On carbon steel shielding gas must contain

minimum of 80% argonminimum of 80% argon Ferrous metals need addition of 2 to 5% oxygen Ferrous metals need addition of 2 to 5% oxygen

to gas mixtureto gas mixture

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Gas Metal Arc DCEP Welding: Wire Positive, Gas Metal Arc DCEP Welding: Wire Positive, Work NegativeWork Negative

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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Direct Current Electrode Negative Direct Current Electrode Negative (DCEN)(DCEN)

Limited use in welding of thin gauge materialsLimited use in welding of thin gauge materials Greatest amount of heat occurs at electrode tipGreatest amount of heat occurs at electrode tip Wire meltoff rate great deal faster than DCEPWire meltoff rate great deal faster than DCEP Penetration also less than with DCEPPenetration also less than with DCEP Arc not stable at end of filler wireArc not stable at end of filler wire

Corrected by use of shielding gas mixture of Corrected by use of shielding gas mixture of 5% oxygen added to argon5% oxygen added to argon

Meltoff rate reduced so benefit cancelledMeltoff rate reduced so benefit cancelled

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Gas Metal Arc DCEN Welding: Wire Negative, Gas Metal Arc DCEN Welding: Wire Negative, Work PositiveWork Positive


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Alternating CurrentAlternating Current

Jarang digunakan dalam GMAWJarang digunakan dalam GMAW Busur tidak stabil oleh karena terjadi arus Busur tidak stabil oleh karena terjadi arus

balikbalik Kombinasi keduanya, yaitu polaritas Kombinasi keduanya, yaitu polaritas

DCEN dan DCEP, terjadi polaritas pada DCEN dan DCEP, terjadi polaritas pada penetrasi penetrasi

Digunakan untuk pengelasan aluminium Digunakan untuk pengelasan aluminium

POSITIVETERMINAL

NEGATIVETERMINAL

Shielding GasesShielding Gases

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

Gas can be Inert, Reactive, or Mixtures of Gas can be Inert, Reactive, or Mixtures of bothboth

Gas flow rate is between 25-35 CFHGas flow rate is between 25-35 CFH Argon, Helium, and Carbon Dioxide are Argon, Helium, and Carbon Dioxide are

the main three gases used in GMAWthe main three gases used in GMAW

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Shielding GasShielding Gas Argon and helium first used for gas metal arcArgon and helium first used for gas metal arc

Continue to be basic gasesContinue to be basic gases Argon used more than helium on ferrous Argon used more than helium on ferrous

metals to keep spatter at minimummetals to keep spatter at minimum Also heavier than air so good weld coverageAlso heavier than air so good weld coverage

Oxygen or carbon dioxide added to pure Oxygen or carbon dioxide added to pure gases to improve arc stability, minimize gases to improve arc stability, minimize undercut, reduce porosity, and improve undercut, reduce porosity, and improve appearance of weldappearance of weld

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Shielding GasShielding Gas Helium added to argon to increase Helium added to argon to increase

penetrationpenetration Hydrogen and nitrogen used for only limited Hydrogen and nitrogen used for only limited

number of special applicationsnumber of special applications Carbon dioxide has following advantages:Carbon dioxide has following advantages:

Low costLow cost High density, resulting in low flow ratesHigh density, resulting in low flow rates Less burn-back problems because of its shorter Less burn-back problems because of its shorter

arc characteristicsarc characteristics

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Specific Metal RecommendationsSpecific Metal Recommendations Aluminum alloys: argon Aluminum alloys: argon Magnesium and aluminum alloys: 75 percent Magnesium and aluminum alloys: 75 percent

helium, 25 percent argon helium, 25 percent argon Stainless steels: argon plus oxygen Stainless steels: argon plus oxygen Magnesium: argon Magnesium: argon Deoxidized copper: 75 percent helium, 25 Deoxidized copper: 75 percent helium, 25

percent argon preferredpercent argon preferred Low alloy steel: argon, plus 2 percent oxygenLow alloy steel: argon, plus 2 percent oxygen

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Specific Metal Specific Metal RecommendationsRecommendations

Mild steel: 15 percent argon, 25 percent Mild steel: 15 percent argon, 25 percent carbon dioxide (dip transfer); 100 percent carbon dioxide (dip transfer); 100 percent COCO22 may also be used with deoxidized may also be used with deoxidized wirewire

Nickel, MonelNickel, Monel®®, and Inconel, and Inconel®®: argon: argon Titanium: argonTitanium: argon Silicon bronze: argonSilicon bronze: argon Aluminum bronze: argonAluminum bronze: argon

FLOW METER

CYLCINDERPRESSUREGAUGE

CFH PRESSURE ADJUSTMENT KNOB

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Specific Metal RecommendationsSpecific Metal Recommendations Aluminum alloys: argon Aluminum alloys: argon Magnesium and aluminum alloys: 75 percent Magnesium and aluminum alloys: 75 percent

helium, 25 percent argon helium, 25 percent argon Stainless steels: argon plus oxygen Stainless steels: argon plus oxygen Magnesium: argon Magnesium: argon Deoxidized copper: 75 percent helium, 25 Deoxidized copper: 75 percent helium, 25

percent argon preferredpercent argon preferred Low alloy steel: argon, plus 2 percent oxygenLow alloy steel: argon, plus 2 percent oxygen

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Specific Metal RecommendationsSpecific Metal Recommendations

Mild steel: 15 percent argon, 25 percent Mild steel: 15 percent argon, 25 percent carbon dioxide (dip transfer); 100 percent carbon dioxide (dip transfer); 100 percent COCO22 may also be used with deoxidized wire may also be used with deoxidized wire

Nickel, MonelNickel, Monel®®, and Inconel, and Inconel®®: argon: argon Titanium: argonTitanium: argon Silicon bronze: argonSilicon bronze: argon Aluminum bronze: argonAluminum bronze: argon

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Joint PreparationJoint Preparation Joint design should provide for most Joint design should provide for most

economical use of filler metaleconomical use of filler metal Correct design for job depends on:Correct design for job depends on:

Type of material being weldedType of material being welded Thickness of materialThickness of material Position of weldingPosition of welding Welding processWelding process Final results desiredFinal results desired Type and size of filler wireType and size of filler wire Welding technique Welding technique

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Joint PreparationJoint Preparation Arc in gas metal arc welding more penetrating Arc in gas metal arc welding more penetrating

and narrower than arc in shielded metal arc and narrower than arc in shielded metal arc welding therefore, smaller root openings may welding therefore, smaller root openings may be used for groove weldsbe used for groove welds Change in joint design increase speed of Change in joint design increase speed of

weldingwelding 100% penetration may be secured in ¼" plate 100% penetration may be secured in ¼" plate

in square butt joint welded from both sidesin square butt joint welded from both sides

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Joint PreparationJoint Preparation No root face recommended for 60No root face recommended for 60º single- or º single- or

double-V butt jointsdouble-V butt joints Root opening should range from 0 to 3/32"Root opening should range from 0 to 3/32" Double-V joints may have wider root openings Double-V joints may have wider root openings

than single-Vthan single-V Plates thicker than 1 inch should have Plates thicker than 1 inch should have

U-groove preparationU-groove preparation Require less weld metal; root face thickness Require less weld metal; root face thickness

should be less than 3/32" and root spacing 1/32 should be less than 3/32" and root spacing 1/32 and 3/32"and 3/32"

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V-Groove, Butt Joint ComparisonV-Groove, Butt Joint Comparison


Multipass mengelas lebih mudah karena sedikit terak, memastikan pembersihan lebih mudah

Untuk Sambungan Fillet, permukaan deposit las lebih sedikit/ kecil pada permukaan material

Jenis sambungan Tertentu ditarik mundur untuk mencegah terjadinya penyumbatan pada torch

Joint PreparationJoint Preparation

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Joint PreparationJoint Preparation

Multipass welding easier since absence of Multipass welding easier since absence of slag ensures easier cleaningslag ensures easier cleaning

For fillet welds deposit smaller weld beads For fillet welds deposit smaller weld beads on surface of materialon surface of material

Certain types of joints backed up to prevent Certain types of joints backed up to prevent weld from projecting through back sideweld from projecting through back side Blocks, strips and bars of copper, steel or Blocks, strips and bars of copper, steel or

ceramicsceramics

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Comparison of Penetration in a Fillet WeldComparison of Penetration in a Fillet Weld

Carbon dioxide shieldedMAG weld versus coated

electrode weld.


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Electrode DiameterElectrode Diameter Influences size of weld bead, depth of Influences size of weld bead, depth of

penetration, and speed of weldingpenetration, and speed of welding General ruleGeneral rule

For same current, arc becomes more penetrating as For same current, arc becomes more penetrating as electrode diameter decreases and deposition rate electrode diameter decreases and deposition rate increasesincreases

To get maximum deposition rate at given current To get maximum deposition rate at given current density, use smallest wire possible consistent density, use smallest wire possible consistent with acceptable weld profilewith acceptable weld profile

Wire 0.045" and larger provide lower deposition Wire 0.045" and larger provide lower deposition rate and deposit wider beads than small wiresrate and deposit wider beads than small wires

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Electrode DiameterElectrode Diameter Filler wires should be same composition as Filler wires should be same composition as

materials being weldedmaterials being welded Position of welding may affect size of electrodePosition of welding may affect size of electrode Welding thin materialWelding thin material

Wires with diameters: 0.023/0.025, 0.030, 0.035"Wires with diameters: 0.023/0.025, 0.030, 0.035" Medium thick materialsMedium thick materials

Wires with diameters: 0.045" or 1/16"Wires with diameters: 0.045" or 1/16" Heavy materialsHeavy materials

Wire with diameter: 1/8"Wire with diameter: 1/8" Small diameters recommended for vertical and Small diameters recommended for vertical and

overhead positionsoverhead positions

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Electrode ExtensionElectrode Extension Length of filler wire that extends pas contact tubeLength of filler wire that extends pas contact tube Area where preheating of filler wire occursArea where preheating of filler wire occurs Also called the stickoutAlso called the stickout Controls dimensions of weld bead since length of Controls dimensions of weld bead since length of

extension affect burnoff rateextension affect burnoff rate Exerts influence on penetration through its effect Exerts influence on penetration through its effect

on welding currenton welding current As extension length increased, preheating of wire As extension length increased, preheating of wire

increases and current reduced which in turn increases and current reduced which in turn decreases amount of penetration into work decreases amount of penetration into work

Stickout distance may vary from 1/8 to 1 1/4"Stickout distance may vary from 1/8 to 1 1/4"

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Electrode ExtensionElectrode Extension Short electrode extensions (1/8–1/2 inch) used for Short electrode extensions (1/8–1/2 inch) used for

short circuit mode of transfer, generally with smaller short circuit mode of transfer, generally with smaller diameter electrodes (0.023–0.045 inches) diameter electrodes (0.023–0.045 inches)

Stainless steel favors shorter electrode extension Stainless steel favors shorter electrode extension because of its higher resistivity (1/8–1/4 inch)because of its higher resistivity (1/8–1/4 inch) Longer and larger diameter electrode extensions used Longer and larger diameter electrode extensions used

for spray arcs (1/2–11/4 inches)for spray arcs (1/2–11/4 inches) Excessive long arcs with active gases reduce the Excessive long arcs with active gases reduce the

mechanical properties in weldmechanical properties in weld Various alloys being burned out as metal transferred Various alloys being burned out as metal transferred

across longer arcacross longer arc

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Electrode ExtensionElectrode Extension Tests indicated that when electrode extension Tests indicated that when electrode extension

increased from 3/16 to 5/8 inch, welding current then increased from 3/16 to 5/8 inch, welding current then drops approximately 60 amperes drops approximately 60 amperes

Current reduced because of change in amount of Current reduced because of change in amount of preheating that takes place in wirepreheating that takes place in wire As electrode extension increased, preheating of wire As electrode extension increased, preheating of wire

increases increases Thus less welding current required from power source at a Thus less welding current required from power source at a

given feed rate given feed rate Because of self-regulating characteristics of constant voltage Because of self-regulating characteristics of constant voltage

power source, welding current decreased power source, welding current decreased As welding current decreased, depth of penetration also As welding current decreased, depth of penetration also

decreasesdecreases

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Nomenclature of Area Between Nozzle and Nomenclature of Area Between Nozzle and WorkpieceWorkpiece


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Position of the GunPosition of the Gun Expressed by two angles: travel and workExpressed by two angles: travel and work Bead shape changed by changing direction of wire Bead shape changed by changing direction of wire

as goes into joint in line of travelas goes into joint in line of travel Gun AngleGun Angle

Can be compared to angle of electrode in shielded Can be compared to angle of electrode in shielded metal arc weldingmetal arc welding

Drag technique results in high narrow bead with deeper Drag technique results in high narrow bead with deeper penetration (10penetration (10º drag angle)º drag angle)

As drag angle reduced, bead height decreases, width As drag angle reduced, bead height decreases, width increasesincreases

Increased travel speeds characteristic of push techniqueIncreased travel speeds characteristic of push technique

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Travel and Work Gun AnglesTravel and Work Gun Angles


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Travel and Work Gun AnglesTravel and Work Gun Angles


Travel Angle(T.A.)

(Drag) Travel Direction

(Push) Travel DirectionWork Angle(W.A.)

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Drag and Push Gun anglesDrag and Push Gun angles


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Drag and Push MethodsDrag and Push Methods

Produces large wide beads Produces flatter bead shape


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Work AngleWork Angle Position of wire to joint in plane Position of wire to joint in plane

perpendicular to line of travelperpendicular to line of travel Filler weld joints: work angle normally Filler weld joints: work angle normally

half of included angle between plates half of included angle between plates forming jointforming joint

Butt welds: work angle normally 90Butt welds: work angle normally 90º to º to surface of plate being joinedsurface of plate being joined

Utilizes natural arc force to push weld Utilizes natural arc force to push weld metal against vertical surface to prevent metal against vertical surface to prevent undercut and provide good bead contourundercut and provide good bead contour

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Work and Gun AnglesWork and Gun Angles


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Arc LengthArc Length Constant voltage welding machine used for Constant voltage welding machine used for

gas metal arc welding provides for self-gas metal arc welding provides for self-adjustment of arc lengthadjustment of arc length Arc length shortened, arc voltage reducedArc length shortened, arc voltage reduced Arc length lengthened, arc voltage increasedArc length lengthened, arc voltage increased

No change in wire-feed speed occursNo change in wire-feed speed occurs Corrected by automatic increase or decrease Corrected by automatic increase or decrease

of burnoff rate of filler wireof burnoff rate of filler wire Welder has complete control of welding Welder has complete control of welding

current and arc length by setting wire-feed current and arc length by setting wire-feed speed on wire feeder and voltage on welding speed on wire feeder and voltage on welding machinemachine

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Arc VoltageArc Voltage Decided effect upon penetration, bead Decided effect upon penetration, bead

height, and bead widthheight, and bead width Chief function to stabilize welding arc and Chief function to stabilize welding arc and

provide smooth, spatter-free weld beadprovide smooth, spatter-free weld bead Higher or lower causes arc to become Higher or lower causes arc to become

unstableunstable Higher: produces wider, flatter bead and Higher: produces wider, flatter bead and

increases possibility of porosity and increases increases possibility of porosity and increases spatter and increases undercut in fillet weldsspatter and increases undercut in fillet welds

Lower: causes bead to be high and narrow Lower: causes bead to be high and narrow

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Arc VoltageArc Voltage High arc voltages result in globular transferHigh arc voltages result in globular transfer

Spatter prone and reduces deposition efficiencySpatter prone and reduces deposition efficiency Has sharp crackling sound when proper arc Has sharp crackling sound when proper arc

voltage for short circuit transfervoltage for short circuit transfer Spray arc have hissing soundSpray arc have hissing sound

Not set to control penetrationNot set to control penetration Better control of weld profile and arc stabilityBetter control of weld profile and arc stability

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Relationship of Arc Length to Weld Bead WidthRelationship of Arc Length to Weld Bead Width


High VoltageLow Voltage

Arc LengthArc Length

Electrode

Electrode

22 - 58

Penetration ComparisonsPenetration Comparisons


Arc voltage too highfor travel speed.

Arc voltage too slowfor travel speed

Proper arc voltagefor speed

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Wire-Feed SpeedWire-Feed Speed Fixed relationship between rate of filler wire burn off Fixed relationship between rate of filler wire burn off

and welding currentand welding current Electrode wire-feed speed determines welding currentElectrode wire-feed speed determines welding current

Current set by wire-feed speed control on wire feederCurrent set by wire-feed speed control on wire feeder Excessive speed, welding machine cannot put out Excessive speed, welding machine cannot put out

enough current to melt wire fast enoughenough current to melt wire fast enough Stubbing or roping of wire occursStubbing or roping of wire occurs Causes convex weld beads and poor appearanceCauses convex weld beads and poor appearance

Decrease in speed results in less electrode being Decrease in speed results in less electrode being meltedmelted

Generally – high setting of filler wire speed rate results Generally – high setting of filler wire speed rate results in short arc, slow speed in long arcin short arc, slow speed in long arc

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Effect of Wire-Feed SpeedsEffect of Wire-Feed Speeds


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Care of NozzlesCare of Nozzles Keep the gun nozzle, contact tube, and Keep the gun nozzle, contact tube, and

wire-feeding system clean to eliminate wire-wire-feeding system clean to eliminate wire-feeding stoppagesfeeding stoppages Nozzle is natural spatter collectorNozzle is natural spatter collector

If spatter builds up thick enough, it can If spatter builds up thick enough, it can actually bridge gap and electrically connect actually bridge gap and electrically connect insulated nozzle to contact tube insulated nozzle to contact tube

To remove spatter, use soft, blunt To remove spatter, use soft, blunt tool for pryingtool for prying


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Care of NozzlesCare of Nozzles Spatter almost falls out by itself if nozzle Spatter almost falls out by itself if nozzle

kept clean, shiny and smoothkept clean, shiny and smooth Antispatter compound may be applied to Antispatter compound may be applied to

gun nozzle and contact tube endgun nozzle and contact tube end Do not clean by tapping or pounding on Do not clean by tapping or pounding on

solid objectsolid object Bends gun nozzles, damages threads and high Bends gun nozzles, damages threads and high

temperature insulation in nozzle can breaktemperature insulation in nozzle can break

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Care of Contact TubesCare of Contact Tubes Transfers welding current to electrode wireTransfers welding current to electrode wire Hole has to be big enough to allow wire with Hole has to be big enough to allow wire with

slight cast to pass through easilyslight cast to pass through easily Wire wears hole to oval shapeWire wears hole to oval shape

Wire slides more easily, but transfer of current not as Wire slides more easily, but transfer of current not as good and arcing in tub resultsgood and arcing in tub results

Spatter flies up into bore and wire slows down Spatter flies up into bore and wire slows down because of frictionbecause of friction

Must be replace; secure tightly in gun and check Must be replace; secure tightly in gun and check periodically for tightnessperiodically for tightness

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Care of Wire-Feed CablesCare of Wire-Feed Cables Wire-feed conduit flexible steel tube that Wire-feed conduit flexible steel tube that

does not stretchdoes not stretch Main source of friction in wire-feed systemMain source of friction in wire-feed system Should be kept clean and straight as possibleShould be kept clean and straight as possible

Clean with dry compressed airClean with dry compressed air Lubricate with dry powdered graphite Lubricate with dry powdered graphite

reduces frictionreduces friction Clean every time spool or coil changesClean every time spool or coil changes

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Bird NestingBird Nesting

Wire coils sideways between wire-feed Wire coils sideways between wire-feed cable and drive rollscable and drive rolls

Prevent by accurate alignment of wire-Prevent by accurate alignment of wire-feed cable inlet guidefeed cable inlet guide Aligned exactly with rollers so wire does not Aligned exactly with rollers so wire does not

have to make reverse bendhave to make reverse bend Notch in drive rolls must be in perfect Notch in drive rolls must be in perfect

alignment to provide smooth passage for wirealignment to provide smooth passage for wire

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Cleanliness of Base MetalCleanliness of Base Metal

Clean area thoroughly before weldingClean area thoroughly before welding Remove all rust, scale, burned edges and Remove all rust, scale, burned edges and

chemical coatingschemical coatings Gas producersGas producers Porosity is resultPorosity is result

Intense heat of arc burns away some of Intense heat of arc burns away some of the contaminantsthe contaminants

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Arc BlowArc Blow Arc blown to one side or other by condition of pull and Arc blown to one side or other by condition of pull and

counter-pull as magnetic field is distortedcounter-pull as magnetic field is distorted Ionized gases carrying arc from end of electrode wire to Ionized gases carrying arc from end of electrode wire to

work act as flexible conductor with magnetic field around itwork act as flexible conductor with magnetic field around it When placed in location such as corner of joint or end of When placed in location such as corner of joint or end of

plate, magnetic field distorted and pulls in another directionplate, magnetic field distorted and pulls in another direction Magnetic field tries to return to state of equilibriumMagnetic field tries to return to state of equilibrium

Does not occur with a.c. welding arcsDoes not occur with a.c. welding arcs Forces exerted by magnetic field reversed 120 times per Forces exerted by magnetic field reversed 120 times per

second thus keeping magnetic field in equilibriumsecond thus keeping magnetic field in equilibrium

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Connecting Work to Minimize Connecting Work to Minimize Arc BlowArc Blow

Suggestions to shorten trial-and-error Suggestions to shorten trial-and-error process to correct or minimize arc blowprocess to correct or minimize arc blow

Attach work lead or leads directly on Attach work lead or leads directly on workpiece if possibleworkpiece if possible

Connect both ends of long, narrow Connect both ends of long, narrow weldmentsweldments

Use electrical conductors of proper lengthUse electrical conductors of proper length Weld away from work connectionWeld away from work connection

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On parts that rotate, use rotating work On parts that rotate, use rotating work connection or allow work cable to wind up connection or allow work cable to wind up no more than one or two turnsno more than one or two turns

In making longitudinal welds on cylinders, In making longitudinal welds on cylinders, use two work connections—one on each use two work connections—one on each side of the seam as close as possible to side of the seam as close as possible to point of startingpoint of starting

If multiple work connections necessary, If multiple work connections necessary, make sure cables are same size and length make sure cables are same size and length and have identical terminalsand have identical terminals

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On multiple-head installations, all heads On multiple-head installations, all heads should weld in same direction and away should weld in same direction and away from work connectionfrom work connection

Use individual work circuits on multiple-Use individual work circuits on multiple-head installationshead installations

Do not place two or more arcs close to one Do not place two or more arcs close to one another on weldments that are prone to another on weldments that are prone to magnetic disturbance with one arc such as magnetic disturbance with one arc such as tubes or tanks requiring longitudinal seamstubes or tanks requiring longitudinal seams

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Setting Up EquipmentSetting Up Equipment Constant voltage d.c. power sourceConstant voltage d.c. power source Wire-feeding mechanism with controls and spooled Wire-feeding mechanism with controls and spooled

or reeled filler wire mounted on fixtureor reeled filler wire mounted on fixture Gas-shielding system consisting of one or more Gas-shielding system consisting of one or more

cylinders of compressed gas, pressure-reducing cylinders of compressed gas, pressure-reducing cylinder regulator, flowmeter assemblycylinder regulator, flowmeter assembly

Combination gas, water, wire, and cable control Combination gas, water, wire, and cable control assembly and welding gun of correct type and size assembly and welding gun of correct type and size

Connecting hoses and cables, work lead, and Connecting hoses and cables, work lead, and clampclamp

Face helmet, gloves, sleeves (if necessary), and Face helmet, gloves, sleeves (if necessary), and assortment of hand toolsassortment of hand tools

22 - 72

Assumed Safety PrecautionsAssumed Safety Precautions Welding equipment installed properlyWelding equipment installed properly Welding machine in dry location, and no water Welding machine in dry location, and no water

on floor of welding boothon floor of welding booth Welding booth lighted and ventilated properlyWelding booth lighted and ventilated properly All connections tight, and all hoses and leads All connections tight, and all hoses and leads

arranged so they cannot be burned or damagedarranged so they cannot be burned or damaged Gas cylinders securely fastened so they cannot Gas cylinders securely fastened so they cannot

fall over and not part of electrical circuitfall over and not part of electrical circuit

22 - 73

Starting ProcedureStarting Procedure

1.1. Check power cable connections; connect gun Check power cable connections; connect gun cable to proper welding terminal on welding cable to proper welding terminal on welding machine and work cable end connected to machine and work cable end connected to proper terminal on welding machineproper terminal on welding machine

2.2. Start welding machine by pressing Start welding machine by pressing onon button button or, in case of engine drive, start engineor, in case of engine drive, start engine

3.3. Turn on wire-feed unitTurn on wire-feed unit4.4. Check gas-shielding supply systemCheck gas-shielding supply system5.5. Check water flow if gun water cooledCheck water flow if gun water cooled

22 - 74

Starting ProcedureStarting Procedure5.5. Set wire-feed speed control for type and size of Set wire-feed speed control for type and size of

filler wire and for jobfiller wire and for job6.6. Voltage rheostat should be set to conform to type Voltage rheostat should be set to conform to type

and thickness of material being welded, diameter of and thickness of material being welded, diameter of filler wire, the type of shielding gas, and type of arcfiller wire, the type of shielding gas, and type of arc

7.7. Adjust for proper electrode extension beyond Adjust for proper electrode extension beyond contact tubecontact tube

8.8. To start arc, touch end of electrode wire to proper To start arc, touch end of electrode wire to proper place on weld joint, usually just ahead of weld place on weld joint, usually just ahead of weld bead, with current shut off; lower helmet and press bead, with current shut off; lower helmet and press gun trigger on torchgun trigger on torch

22 - 75

Shutting Down the EquipmentShutting Down the Equipment

1.1. Stop welding and release gun triggerStop welding and release gun trigger2.2. Return feed speed to zero positionReturn feed speed to zero position3.3. Close gas outlet valve in top of gas Close gas outlet valve in top of gas

cylindercylinder4.4. Squeeze welding gun trigger, hold it down, Squeeze welding gun trigger, hold it down,

and bleed gas linesand bleed gas lines5.5. Close gas flowmeter valve until finger-tightClose gas flowmeter valve until finger-tight6.6. Shut off welding machine and wire feederShut off welding machine and wire feeder7.7. Hang up welding gun and cable assemblyHang up welding gun and cable assembly

22 - 76

Starting the WeldStarting the Weld Running startRunning start

Arc started at beginning of weldArc started at beginning of weld Electrode end put in contact with base metalElectrode end put in contact with base metal Trigger on torch pressedTrigger on torch pressed Tends to be too cold at beginning of weldTends to be too cold at beginning of weld

Scratch startScratch start Arc struck approximately 1 inch ahead of beginning of weldArc struck approximately 1 inch ahead of beginning of weld Arc quickly moved back to starting point of weld, direction Arc quickly moved back to starting point of weld, direction

of travel reversed, and weld startedof travel reversed, and weld started Arc may also be struck outside of weld area on starting tabArc may also be struck outside of weld area on starting tab

22 - 77

Finishing the WeldFinishing the Weld Arc should be manipulated to reduce penetration Arc should be manipulated to reduce penetration

depth and weld pool size when completing weld depth and weld pool size when completing weld beadbead Decreases final shrinkage areaDecreases final shrinkage area Reduction accomplished by rapidly increasing speed of Reduction accomplished by rapidly increasing speed of

welding for approximately 1 to 2 inches of weld lengthwelding for approximately 1 to 2 inches of weld length Trigger released, stopping wire feed and interrupting Trigger released, stopping wire feed and interrupting

welding currentwelding current Gun trigger can be turned on and off several times Gun trigger can be turned on and off several times

at end of weld to fill craterat end of weld to fill crater

22 - 78

Gun AngleGun Angle Push angle of 5° to 15° generally employed when Push angle of 5° to 15° generally employed when

welding in flat positionwelding in flat position Take care push angle not changed as end of weld Take care push angle not changed as end of weld

approachedapproached Work angle equal on all sides when welding uniform Work angle equal on all sides when welding uniform

thicknessesthicknesses Welding in horizontal position, point gun upward Welding in horizontal position, point gun upward

slightlyslightly Thick-to-thin joints, direct arc toward heavier sectionThick-to-thin joints, direct arc toward heavier section Slight drag angle may help when welding thin Slight drag angle may help when welding thin

sectionssections

22 - 79

Control of ArcControl of Arc

Arc voltage controls penetration, bead Arc voltage controls penetration, bead contour, and such defects as undercutting, contour, and such defects as undercutting, porosity and weld discontinuitiesporosity and weld discontinuities

Arc should be occasionally noisy for most Arc should be occasionally noisy for most applications of spray arcsapplications of spray arcs

22 - 80

Practice JobsPractice Jobs

Practice gas metal arc welding on mild Practice gas metal arc welding on mild steel, aluminum, and stainless steelsteel, aluminum, and stainless steel

Specifications given in Job Outline in order Specifications given in Job Outline in order assigned by instructorassigned by instructor

Beyond these job, practice other forms of Beyond these job, practice other forms of joints in all positionsjoints in all positions Use various types and sizes of filler wire and Use various types and sizes of filler wire and

different shielding gasesdifferent shielding gases

22 - 81

MIG/MAG Welding of MIG/MAG Welding of Carbon SteelCarbon Steel

Bulk of all welding done on carbon steelBulk of all welding done on carbon steel MIG/MAG welding on increaseMIG/MAG welding on increase

Welders find it relatively easy to masterWelders find it relatively easy to master Consistently produces sound welds at high Consistently produces sound welds at high

rate of speedrate of speed

22 - 82

Groove Welds: Groove Welds: Jobs 22-J1 and J2Jobs 22-J1 and J2

Plate up to 1/8" thick may be butt welded with Plate up to 1/8" thick may be butt welded with square edges with root opening of 0 to 1/16"square edges with root opening of 0 to 1/16"

Heavier plate, 3/16 and 1/4 inch may be Heavier plate, 3/16 and 1/4 inch may be welded without beveling edges if 1/16 to 3/32" welded without beveling edges if 1/16 to 3/32" opening providedopening provided

Bead should be wider than root spacing for Bead should be wider than root spacing for proper fusionproper fusion

Two passes, one from each side usually Two passes, one from each side usually neededneeded

22 - 83


For code welding, plate thicknesses from For code welding, plate thicknesses from 3/16 to 1" should be beveled3/16 to 1" should be beveled 6060º single- or double-V without root face º single- or double-V without root face

recommendedrecommended Root opening of 0 to 1/16" should be maintainedRoot opening of 0 to 1/16" should be maintained Wider root openings may be provided for Wider root openings may be provided for

double-V jointsdouble-V joints Single-V grooves backing pass from reverse Single-V grooves backing pass from reverse

side generally requiredside generally required Less distortion when welding from both Less distortion when welding from both

sides of jointsides of joint

22 - 84


Open root joint should be run using short Open root joint should be run using short circuit or pulse spray for ferrous metalscircuit or pulse spray for ferrous metals

Practice 3G using both uphill and downhill Practice 3G using both uphill and downhill techniquestechniques

U-grooves used on plate thicker than 1 inchU-grooves used on plate thicker than 1 inch Root spacing between 1/32 and 3/32" Root spacing between 1/32 and 3/32"

maintainedmaintained Root face of 3/32" or less to assure penetrationRoot face of 3/32" or less to assure penetration Requires less filler metal than V groove butt jointRequires less filler metal than V groove butt joint

22 - 85


Argon-oxygen mixture containing 1-5% oxygen Argon-oxygen mixture containing 1-5% oxygen recommended for spray arc weldingrecommended for spray arc welding Oxygen improves flow of weld metal and reduces Oxygen improves flow of weld metal and reduces

tendency to undercuttendency to undercut Argon with 10% COArgon with 10% CO22 sometimes used sometimes used Carbon dioxide at 100% used by arc not true Carbon dioxide at 100% used by arc not true

spray arcspray arc Popular for MAG small wire weldingPopular for MAG small wire welding

Short arc welding of carbon steel uses mixture of Short arc welding of carbon steel uses mixture of 75% argon and 25% carbon dioxide75% argon and 25% carbon dioxide

22 - 86

Fillet Welds: Jobs 22-J3-J10Fillet Welds: Jobs 22-J3-J10 Used in T-joints, lap joints, and corner jointsUsed in T-joints, lap joints, and corner joints Deposit rate and rate of travel high with deep Deposit rate and rate of travel high with deep

penetrationpenetration Permits smaller fillet welds than with stick Permits smaller fillet welds than with stick

electrode weldingelectrode welding Position of nozzle and speed of welding importantPosition of nozzle and speed of welding important Welding may be single pass or multipassWelding may be single pass or multipass

Multipass may be done with stringer or weave beadsMultipass may be done with stringer or weave beads Each pass must be cleaned carefullyEach pass must be cleaned carefully

22 - 87

Inspection and TestingInspection and Testing


Outside corner joint in steel plate welded with gas metalarc welding process in the flat position.

Penetration through back side of corner joint weldedin the flat position.

22 - 88


Fillet weld on lap joint in steel platewelded with gas metal arc weldingprocess in 2F position.


Fillet weld on lap joint in steel plate weldedwith gas metal arc welding process in 3Fposition, downhill. Note porosity caused

by poor gas shielding.

22 - 89



Fillet weld on T-joint weldedin the 2F position with the

gas metal arc welding process in steel plate.

Penetration through back side of a V-groove butt joint welded

in the 1G position.

The first (root) pass of a V-groovebutt joint welded in the 1G position

with the gas metal arc welding process in steel plate.

22 - 90

Fillet and Groove Welding Combination Fillet and Groove Welding Combination Project: Project:

Job Qualification Test 1Job Qualification Test 1

PurposePurpose Ability to read printAbility to read print Develop bill of materialsDevelop bill of materials Thermally cutThermally cut Fit components togetherFit components together Tack and weld carbon steel projectTack and weld carbon steel project

Follow instructions found in Fig. 22-26Follow instructions found in Fig. 22-26

22 - 91

Fillet and Groove Welding Combination Fillet and Groove Welding Combination Project: Project:

Job Qualification Test 1Job Qualification Test 1 Inspection and testing (visual inspection only)Inspection and testing (visual inspection only)

Shall be no cracks or incomplete fusionShall be no cracks or incomplete fusion Shall be no incomplete joint penetration in groove Shall be no incomplete joint penetration in groove

welds except as permitted for partial joint penetration welds except as permitted for partial joint penetration groove weldsgroove welds

Undercut shall not exceed lesser of 10% of base metal Undercut shall not exceed lesser of 10% of base metal thickness or 1/32 inchthickness or 1/32 inch

Frequency of porosity shall not exceed one in each 4 Frequency of porosity shall not exceed one in each 4 inches of weld length, and maximum diameter shall inches of weld length, and maximum diameter shall not exceed 3/32 inchnot exceed 3/32 inch

Welds shall be free from overlapWelds shall be free from overlap Only minimal weld spatter shall be acceptedOnly minimal weld spatter shall be accepted

22 - 92

Fillet and Groove Welding Combination Fillet and Groove Welding Combination Project: Job Qualification Test2Project: Job Qualification Test2

PurposePurpose Ability to read printAbility to read print Develop bill of materialsDevelop bill of materials Thermally cutThermally cut Fit components togetherFit components together Tack and weld carbon steel projectTack and weld carbon steel project Use spray arc mode of metal transferUse spray arc mode of metal transfer Note on Fig. 22-27Note on Fig. 22-27

22 - 93

Fillet and Groove Welding Combination Fillet and Groove Welding Combination Project: Job Qualification Test2Project: Job Qualification Test2

Inspection and testing (visual inspection only)Inspection and testing (visual inspection only) Shall be no cracks or incomplete fusionShall be no cracks or incomplete fusion Shall be no incomplete joint penetration in groove Shall be no incomplete joint penetration in groove

welds except as permitted for partial joint penetration welds except as permitted for partial joint penetration groove weldsgroove welds

Undercut shall not exceed lesser of 10% of base metal Undercut shall not exceed lesser of 10% of base metal thickness or 1/32 inchthickness or 1/32 inch

Frequency of porosity shall not exceed one in each 4 Frequency of porosity shall not exceed one in each 4 inches of weld length, and the maximum diameter inches of weld length, and the maximum diameter shall not exceed 3/32 inchshall not exceed 3/32 inch


22 - 94

Groove Weld Project: Job Groove Weld Project: Job Qualification Test 3Qualification Test 3

ProjectProject Ability to read printAbility to read print Fit components togetherFit components together Tack and weld carbon steel unlimited Tack and weld carbon steel unlimited

thickness test platethickness test plate Using spray arc mode of metal transferUsing spray arc mode of metal transfer Instructions in notes in Fig. 22-28Instructions in notes in Fig. 22-28

22 - 95

Inspection and TestingInspection and Testing After tacking, have it inspectedAfter tacking, have it inspected After complete welding, use visual inspection After complete welding, use visual inspection

and cut specimens for bend testingand cut specimens for bend testing Use side bend test procedures and check:Use side bend test procedures and check: Testing criteria:Testing criteria:

No cracks or incomplete fusionNo cracks or incomplete fusion No incomplete joint penetration in groove welds No incomplete joint penetration in groove welds

except as permitted for partial joint penetration except as permitted for partial joint penetration groove weldsgroove welds

22 - 96


Testing criteria (cont.): Testing criteria (cont.): Undercut shall not exceed lesser of 10 Undercut shall not exceed lesser of 10

percent of base metal thickness or 1/32 inchpercent of base metal thickness or 1/32 inch Frequency of porosity shall not exceed one in Frequency of porosity shall not exceed one in

each 4 inches of weld length and maximum each 4 inches of weld length and maximum diameter shall not exceed 3/32 inchdiameter shall not exceed 3/32 inch


22 - 97

Side Bend Acceptance Criteria as Measured on Side Bend Acceptance Criteria as Measured on Convex Surface of Bend SpecimenConvex Surface of Bend Specimen

No single indication shall exceed 1/8 inch No single indication shall exceed 1/8 inch measured in any direction on surfacemeasured in any direction on surface

Sum of greatest dimensions of all indications on Sum of greatest dimensions of all indications on surface, which exceed 1/32 inch, but are less surface, which exceed 1/32 inch, but are less than or equal to 1/8 inch, shall not exceed 3/8 than or equal to 1/8 inch, shall not exceed 3/8 inchinch

Cracks occurring at corner of specimens shall not Cracks occurring at corner of specimens shall not be considered unless there definite evidence that be considered unless there definite evidence that they result from slag inclusions or other internal they result from slag inclusions or other internal discontinuitiesdiscontinuities

22 - 98

MIG Welding of AluminumMIG Welding of Aluminum Readily joined by welding, brazing, soldering, adhesive Readily joined by welding, brazing, soldering, adhesive

bonding, and mechanical fasteningbonding, and mechanical fastening LightweightLightweight Alloyed readily with many other metalsAlloyed readily with many other metals Highly ductile and retains ductility at subzero Highly ductile and retains ductility at subzero

temperaturestemperatures High resistance to corrosion, no colored salts, not toxicHigh resistance to corrosion, no colored salts, not toxic Good electrical and thermal conductivityGood electrical and thermal conductivity High reflectivity to both heat and lightHigh reflectivity to both heat and light Nonsparking and nonmagneticNonsparking and nonmagnetic

22 - 99

MIG Welding of AluminumMIG Welding of Aluminum

Easy to fabricateEasy to fabricate May be given wide variety of mechanical, May be given wide variety of mechanical,

electrochemical, chemical and paint finisheselectrochemical, chemical and paint finishes Needs high heat input for fusion weldingNeeds high heat input for fusion welding Aluminum and its alloys rapidly develop oxide Aluminum and its alloys rapidly develop oxide

film when exposed to air (melting point 3600film when exposed to air (melting point 3600ºF)ºF) Must be removed during welding Must be removed during welding

• Removed by fluxes, action of arc in inert gas Removed by fluxes, action of arc in inert gas atmosphere or mechanical and chemical meansatmosphere or mechanical and chemical means

22 - 100

MIG Welding of AluminumMIG Welding of Aluminum

MIG and TIG replaced stick electrode MIG and TIG replaced stick electrode welding for aluminum and its alloyswelding for aluminum and its alloys Small percentage still using stick electrodesSmall percentage still using stick electrodes

Type of joint and position of welding Type of joint and position of welding determines process to used on determines process to used on thicknesses thicknesses 1/8 inch and under1/8 inch and under

22 - 101

Factors that Make Gas Metal Arc Factors that Make Gas Metal Arc Welding Desirable Joining Process for Welding Desirable Joining Process for

AluminumAluminum Cleaning time reduced because there no Cleaning time reduced because there no

flux on weldflux on weld Absence of slag in weld pool eliminates Absence of slag in weld pool eliminates

possibility of entrapmentpossibility of entrapment Weld pool highly visible due to absence of Weld pool highly visible due to absence of

smoke and fumessmoke and fumes Welding can be done in all positionsWelding can be done in all positions

22 - 102

Joint PreparationJoint Preparation Designed like those for steelDesigned like those for steel Narrower joint spacing and lower welding currents Narrower joint spacing and lower welding currents

usedused Foreign substances must be removedForeign substances must be removed

Wiped off or removed by vapor degreasingWiped off or removed by vapor degreasing Oxide film removed by chemical and mechanical Oxide film removed by chemical and mechanical

cleaning methodscleaning methods Weld as soon as possible before oxide film has Weld as soon as possible before oxide film has

chance to form againchance to form again Sheared edges can also cause poor quality weldsSheared edges can also cause poor quality welds

22 - 103

Shielding GasShielding Gas Argon preferred for welding aluminum plate Argon preferred for welding aluminum plate

thicknesses up to 1 inchthicknesses up to 1 inch Plate thicknesses 1-2 inches may use:Plate thicknesses 1-2 inches may use:

Pure argon, mixture of 50% argon and 50% helium, or Pure argon, mixture of 50% argon and 50% helium, or mixture of 75% argon and 25% heliummixture of 75% argon and 25% helium

Helium provides high heat and argon excellent Helium provides high heat and argon excellent cleaning actioncleaning action

Plate thicknesses from 2-3 inchesPlate thicknesses from 2-3 inches Mixture of 50% argon and 50% helium or 25% argon Mixture of 50% argon and 50% helium or 25% argon

and 75% heliumand 75% helium Plate thicknesses greater than 3 inchesPlate thicknesses greater than 3 inches

Mixture of 25% argon and 75% heliumMixture of 25% argon and 75% helium

22 - 104

Spray Arc WeldingSpray Arc Welding Weld metal deposited continuouslyWeld metal deposited continuously More arc energy and greater heat provided for More arc energy and greater heat provided for

melting filler wire and base materialmelting filler wire and base material Helium, helium-argon mixtures and argon used Helium, helium-argon mixtures and argon used

as shielding gasesas shielding gases Choice dependent upon type of material, thickness Choice dependent upon type of material, thickness

and welding positionand welding position Welding can be done in all positionsWelding can be done in all positions GMAW-P very effective when welding aluminumGMAW-P very effective when welding aluminum

22 - 105

Out-of-Position WeldingOut-of-Position Welding

Horizontal positionHorizontal position Care must be taken to penetrate to root of Care must be taken to penetrate to root of

joint when welding butt joints and T-jointsjoint when welding butt joints and T-joints Overheating in any one area causes sagging, Overheating in any one area causes sagging,

undercutting or melt-through to back of jointundercutting or melt-through to back of joint Weld metal should be directed against upper Weld metal should be directed against upper

plateplate In multipass welding, be sure fusion between In multipass welding, be sure fusion between

passespasses

22 - 106

Horizontal PositionHorizontal Position

Welding T-joint in aluminumplate in 2F position

Welding V-groove butt jointin aluminum plate in 2G position.


22 - 107

Out-Of-Position WeldingOut-Of-Position Welding Vertical positionVertical position

Travel-up technique on fillet and groove weldsTravel-up technique on fillet and groove welds Do not use too high welding current nor deposit too large Do not use too high welding current nor deposit too large

weld beadweld bead Slight side-to-side motion helpfulSlight side-to-side motion helpful

Overhead positionOverhead position No problem with fillet and groove weldsNo problem with fillet and groove welds Welding current and travel speed lower than flat positionWelding current and travel speed lower than flat position Gas flow rate higher because gas has tendency to leave Gas flow rate higher because gas has tendency to leave

areaarea Somewhat awkward – assume relaxed position as possibleSomewhat awkward – assume relaxed position as possible

22 - 108

Out-Of-Position WeldingOut-Of-Position Welding


Welding V-groove butt joint inaluminum plate in 3G position, uphill.

Welding T-joint in aluminum plate in 3F position, uphill.

22 - 109

Butt Joints: Jobs 22-J11 and Butt Joints: Jobs 22-J11 and J12J12

Easy to designEasy to design Require minimum of base materialRequire minimum of base material Perform better under fatigue loadingPerform better under fatigue loading Require accurate alignment and edge preparationRequire accurate alignment and edge preparation Usually necessary to bevel edge on thicknesses Usually necessary to bevel edge on thicknesses

of ¼" or more to permit root pass penetrationof ¼" or more to permit root pass penetration On heavier plate, chipping back side and welding back On heavier plate, chipping back side and welding back

side with one passside with one pass Sections with different thicknesses should be beveled Sections with different thicknesses should be beveled

before weldingbefore welding

22 - 110

Lap Joints: Job 22-J13Lap Joints: Job 22-J13

More widely used on aluminum alloys than More widely used on aluminum alloys than on other materialson other materials

Use double-welded, single-lap joints in Use double-welded, single-lap joints in thicknesses of aluminum up to ½"thicknesses of aluminum up to ½"

Require no edge preparationRequire no edge preparation Easy to fitEasy to fit Require less jigging than butt jointsRequire less jigging than butt joints

22 - 111

T-Joints: Jobs 22-J14-J16T-Joints: Jobs 22-J14-J16 Seldom require edge preparation on material ¼" or Seldom require edge preparation on material ¼" or

less in thicknessless in thickness Fully penetrated if weld fused into root of jointFully penetrated if weld fused into root of joint Easily fitted and normally require no back chippingEasily fitted and normally require no back chipping Jigging usually quite simpleJigging usually quite simple Better to put small continuous fillet weld on each Better to put small continuous fillet weld on each

side of joint rather than one large weld on one sideside of joint rather than one large weld on one side Continuous fillet welding recommended over Continuous fillet welding recommended over

intermittent welding for longer fatigue lifeintermittent welding for longer fatigue life

22 - 112

Edge and Corner JointsEdge and Corner Joints

Economical from standpoint of Economical from standpoint of preparation, base metal used, and welding preparation, base metal used, and welding requirementsrequirements

Harder to fit up Harder to fit up Prone to fatigue failureProne to fatigue failure Edges do not require preparationEdges do not require preparation

22 - 113


Inspect carefully for defectsInspect carefully for defects Use same inspection and testing Use same inspection and testing

procedures used previouslyprocedures used previously Look for surface defectsLook for surface defects High quality welds in aluminum can be High quality welds in aluminum can be

produced only if proper welding conditions produced only if proper welding conditions and good cleaning procedures been and good cleaning procedures been established and maintainedestablished and maintained

22 - 114

Effect of Current on Effect of Current on Aluminum WeldsAluminum Welds


Aluminum weld bead made with current

too high

Aluminum weld bead made with current

too low

Aluminum weld bead made with

correct current

Kaiser Aluminum & Chemical Corporation Kaiser Aluminum & Chemical Corporation Kaiser Aluminum & Chemical Corporation

22 - 115

Main Causes of Cracking in Main Causes of Cracking in Aluminum WeldsAluminum Welds

Generally in crater or longitudinal formGenerally in crater or longitudinal form Crater cracksCrater cracks

Cause: arc broken sharply and leaves craterCause: arc broken sharply and leaves crater Cure: manipulate gun properlyCure: manipulate gun properly

Longitudinal cracks caused byLongitudinal cracks caused by Incorrect weld metal compositionIncorrect weld metal composition Improper welding procedureImproper welding procedure High stresses imposed during welding by poor High stresses imposed during welding by poor

joint design or poor jiggingjoint design or poor jigging

22 - 116

Main Causes of Porosity in Main Causes of Porosity in Aluminum WeldsAluminum Welds

Hydrogen in the weld areaHydrogen in the weld area Moisture, oil, grease, or heavy oxides in the weld Moisture, oil, grease, or heavy oxides in the weld

areaarea Improper voltage or arc lengthImproper voltage or arc length Improper or erratic wire feedImproper or erratic wire feed Contaminated filler wire (Use as large a diameter Contaminated filler wire (Use as large a diameter

as possible and GMAW-P if lower heat is needed.)as possible and GMAW-P if lower heat is needed.) Leaky gun Leaky gun Contaminated or insufficient shielding gasContaminated or insufficient shielding gas

22 - 117

Major Causes of Incomplete Fusion of Major Causes of Incomplete Fusion of Weld Metal with Base MetalWeld Metal with Base Metal

Incomplete removal of oxide film before Incomplete removal of oxide film before weldingwelding

Unsatisfactory cleaning between passesUnsatisfactory cleaning between passes Insufficient bevel or back chippingInsufficient bevel or back chipping Improper amperage (WFS) or voltageImproper amperage (WFS) or voltage

22 - 118

Causes of Inadequate Penetration at Causes of Inadequate Penetration at Root of Weld and Into Side Walls of Root of Weld and Into Side Walls of

JointJoint Low welding current (WFS)Low welding current (WFS) Improper filler metal sizeImproper filler metal size Improper joint preparationImproper joint preparation Too fast travel speeds for the selected Too fast travel speeds for the selected

wire-feed speedwire-feed speed

22 - 119

Causes of Metallic and Nonmetallic Causes of Metallic and Nonmetallic Inclusions in Aluminum WeldsInclusions in Aluminum Welds

Copper inclusions caused by burn-back of Copper inclusions caused by burn-back of electrode to contact tubeelectrode to contact tube

Metallic inclusions from cleaning weld with Metallic inclusions from cleaning weld with wire brush which leaves bristles in weldwire brush which leaves bristles in weld

Nonmetallic inclusions from poor cleaning Nonmetallic inclusions from poor cleaning of base metalof base metal

Always use push gun travel angle when Always use push gun travel angle when welding aluminumwelding aluminum

22 - 120

Groove Weld Project: Groove Weld Project: Job Qualification Test 4Job Qualification Test 4

PurposePurpose Ability to read printAbility to read print Fit components togetherFit components together TackTack Weld aluminum test platesWeld aluminum test plates Using spray arc mode of metal transferUsing spray arc mode of metal transfer

Inspection and testingInspection and testing Visual inspectionVisual inspection Perform side bend testsPerform side bend tests

22 - 121Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Performance QualificationTest GMAW Spray Transfer, Aluminum3G and 4G Positions

AWS SENSE

Shown only to illustrate what a qualification test wouldlook like. Follow it and inspect and test as listed in text.

22 - 122

MAG Welding of Stainless SteelMAG Welding of Stainless Steel

Heat and corrosion resistant alloyHeat and corrosion resistant alloy Always contains high percentage of chromium in Always contains high percentage of chromium in

addition to nickel and manganeseaddition to nickel and manganese Excellent strength-to-weight ratiosExcellent strength-to-weight ratios Many alloys possess high degree of ductilityMany alloys possess high degree of ductility Widely used in products such as tubing, Widely used in products such as tubing,

piping, kitchen equipment, ball bearingspiping, kitchen equipment, ball bearings Supplied in sheets, strip, plate, shapes, Supplied in sheets, strip, plate, shapes,

tubing, pipe and wire extrusionstubing, pipe and wire extrusions

22 - 123

MAG Welding of Stainless SteelMAG Welding of Stainless Steel Lower rate of thermal conductivity than carbon steelLower rate of thermal conductivity than carbon steel

Heat retained in weld zone longerHeat retained in weld zone longer Thermal expansion greater than carbon steelThermal expansion greater than carbon steel

Causes greater shrinkage stresses and warpageCauses greater shrinkage stresses and warpage Has tendency to undercutHas tendency to undercut All standard forms of joints used in fabricationsAll standard forms of joints used in fabrications Copper backing bars necessary for welding Copper backing bars necessary for welding

sections up to 1/16" thicksections up to 1/16" thick No air must be permitted to reach underside of No air must be permitted to reach underside of

weld while weld pool solidifying (air weakens it)weld while weld pool solidifying (air weakens it) If no backing bar, argon should be used as purge gas If no backing bar, argon should be used as purge gas

shieldshield

22 - 124

Advantages of MAG Welding Advantages of MAG Welding Stainless SteelStainless Steel

Absence of slag-forming flux reduces Absence of slag-forming flux reduces cleaning time and makes it possible to cleaning time and makes it possible to observe weld poolobserve weld pool

Continuous wire feed permits Continuous wire feed permits uninterrupted weldinguninterrupted welding

MAG lends itself to automationMAG lends itself to automation Welding may be performed with short-Welding may be performed with short-

circuiting, spray, or pulsed spray modes of circuiting, spray, or pulsed spray modes of transfertransfer

22 - 125

Spray Arc WeldingSpray Arc Welding Electrode diameters as large as 3/32" can be Electrode diameters as large as 3/32" can be

used for stainless steelused for stainless steel 1/16" wire used with high current to create spray arc 1/16" wire used with high current to create spray arc

transfer of metaltransfer of metal DCEP used for most stainless-steel weldingDCEP used for most stainless-steel welding Most common gas: mixture of Ar and 1 to 2% OMost common gas: mixture of Ar and 1 to 2% O

Recommended for single-pass weldingRecommended for single-pass welding Push travel angle should be employed on plate Push travel angle should be employed on plate

¼" thick or more¼" thick or more Gun should be moved back and forth in direction Gun should be moved back and forth in direction

of travel and slightly from side to sideof travel and slightly from side to side

22 - 126

Short Arc Welding (GMAW-S)Short Arc Welding (GMAW-S) Requires low current ranging form 20 to 175 Requires low current ranging form 20 to 175

amperes; low voltage of 12 to 20 volts, small amperes; low voltage of 12 to 20 volts, small diameter wiresdiameter wires

Metal transfer occurs when filler wire short circuits Metal transfer occurs when filler wire short circuits with base metalwith base metal

Ideally suited for most stainless-steel welding on Ideally suited for most stainless-steel welding on thicknesses from 16 gauge to 1/16"thicknesses from 16 gauge to 1/16" Also for first pass in which fitup is poor or copper Also for first pass in which fitup is poor or copper

backing unsuitablebacking unsuitable Very desirable in vertical and overhead positions for Very desirable in vertical and overhead positions for

first passfirst pass

22 - 127

Short Arc Welding (GMAW-S)Short Arc Welding (GMAW-S) For stainless steel in light gauges, triple For stainless steel in light gauges, triple

mixture of gas gives good arc stability and mixture of gas gives good arc stability and excellent coalescenceexcellent coalescence 90% helium, 7 ½% argon and 2 ½% carbon 90% helium, 7 ½% argon and 2 ½% carbon

dioxidedioxide Produces small heat-affected zone that eliminates Produces small heat-affected zone that eliminates

undercutting and reduces distortionundercutting and reduces distortion Does not lower corrosion resistanceDoes not lower corrosion resistance Flow rates must be increased because of lower Flow rates must be increased because of lower

density of heliumdensity of helium

22 - 128

Pulse Spray Arc (GMAW-P)Pulse Spray Arc (GMAW-P) Can be done with lower current levels and Can be done with lower current levels and

higher wire-feed speedshigher wire-feed speeds Can be used on all thickness rangesCan be used on all thickness ranges Spray-type gas: 1 and 2% oxygen with Spray-type gas: 1 and 2% oxygen with

remainder being argon most commonremainder being argon most common Weld more fluid and flows well because arc Weld more fluid and flows well because arc

on all the timeon all the time Spatter reduced on thin base metals as Spatter reduced on thin base metals as

compared to short-circuiting mode of transfercompared to short-circuiting mode of transfer

22 - 129

Hot CrackingHot Cracking

Tendency of some stainless steelsTendency of some stainless steels More welding passes neededMore welding passes needed Stringer beads recommended instead of Stringer beads recommended instead of

weaveweave• Reduce contraction stresses and cooling more Reduce contraction stresses and cooling more

rapidrapid Can reduce when welding sections 1 inch Can reduce when welding sections 1 inch

or thicker by preheating to 500or thicker by preheating to 500ºFºF Also reduce by GMAW-S or P weldingAlso reduce by GMAW-S or P welding

22 - 130

Stainless-Steel SensitizationStainless-Steel Sensitization Carbide precipitationCarbide precipitation

Sensitizing chromium out of individual grains of Sensitizing chromium out of individual grains of austenitic types of stainless steelaustenitic types of stainless steel

Occurs most readily in 1,200Occurs most readily in 1,200ºF heat rangeºF heat range To reduce situationTo reduce situation

Use GMAW process with its rapid speed and high Use GMAW process with its rapid speed and high deposition ratedeposition rate

Use stabilized and low carbon grades of stainless steelUse stabilized and low carbon grades of stainless steel Using proper filler metals such as ER308L which is low Using proper filler metals such as ER308L which is low

in carbonin carbon

22 - 131

Inspection and Testing: Inspection and Testing: Jobs 22-J17-J23Jobs 22-J17-J23

Inspect each weld carefully for defectsInspect each weld carefully for defects

Fillet weld on lap joint in 3/8" stainless-steel plate weldedin the 1F position with the gas metal arc welding process.


22 - 132

Inspection and Testing: Inspection and Testing: Jobs 22-J17-J23Jobs 22-J17-J23

Fillet weld on T-joint in 3/8" stainless-steel platewelded in 1F position with gas metal arc welding process.

Fillet weld on T-joint in 3/8" stainless-steel platewelded in 2F position with gas metal arc welding process.


22 - 133

Copper and Its AlloysCopper and Its Alloys May be welded successfully by gas metal arc May be welded successfully by gas metal arc

processprocess Electrolytic copper can be joined by using special Electrolytic copper can be joined by using special

techniques, but weldability not goodtechniques, but weldability not good Various grades of deoxidized copper readily weldable Various grades of deoxidized copper readily weldable

with MIG processwith MIG process Deoxidized filler wires necessaryDeoxidized filler wires necessary

Filler wires of approximately matching chemistry Filler wires of approximately matching chemistry usedused

Argon preferred shielding gas for material 1" and Argon preferred shielding gas for material 1" and thinnerthinner Flow of 50 cubic feet per hour sufficientFlow of 50 cubic feet per hour sufficient Heavier material uses 65% and 35% argonHeavier material uses 65% and 35% argon

22 - 134

Copper and Its AlloysCopper and Its Alloys

Joint design like any other metalJoint design like any other metal Steel backup necessary for sheets 1/8" or Steel backup necessary for sheets 1/8" or

thinnerthinner Welding currents on high side requiredWelding currents on high side required

Preheat not required when welding ¼" or lessPreheat not required when welding ¼" or less Always provide good ventilation when Always provide good ventilation when

welding copper and its alloyswelding copper and its alloys Beryllium-copper alloy dangerousBeryllium-copper alloy dangerous

22 - 135

Copper and Its AlloysCopper and Its Alloys

GMAW-BGMAW-B Variation of GMAW process where B indicates Variation of GMAW process where B indicates

brazing or just MIG brazingbrazing or just MIG brazing Uses silicon-bronze type electrode with inert Uses silicon-bronze type electrode with inert

shielding with Argon 100% most commonshielding with Argon 100% most common Main application for coated carbon steel sheet Main application for coated carbon steel sheet

metal (light gauge)metal (light gauge) Zinc coating applied for corrosion resistance Zinc coating applied for corrosion resistance Base metal not melted (hence brazing operation)Base metal not melted (hence brazing operation)

22 - 136

Nickel and Nickel-Copper AlloysNickel and Nickel-Copper Alloys Can be welded using gas metal arc processCan be welded using gas metal arc process Remove all foreign material in vicinity since Remove all foreign material in vicinity since

susceptible to severe embrittlement and susceptible to severe embrittlement and cracking when come in contact with foreign cracking when come in contact with foreign materialsmaterials

Argon generally preferable for welding up to Argon generally preferable for welding up to about 3/8 inch in thickness about 3/8 inch in thickness Above that thickness, argon-helium mixtures Above that thickness, argon-helium mixtures

usually more desirableusually more desirable Joint preparation like other metalsJoint preparation like other metals

22 - 137

MagnesiumMagnesium Silvery white metal, two-thirds weight of aluminum Silvery white metal, two-thirds weight of aluminum

and one-quarter weight of steeland one-quarter weight of steel Melting point of 1,204Melting point of 1,204ºFºF Strength-to-weight ratio high when compared to Strength-to-weight ratio high when compared to

steelsteel Welding techniques like aluminumWelding techniques like aluminum

Rate of expansion greaterRate of expansion greater Care taken that surface clean before weldingCare taken that surface clean before welding

Arc characteristics of helium and argon with Arc characteristics of helium and argon with magnesium different than with other metalsmagnesium different than with other metals Argon recommended in most casesArgon recommended in most cases

22 - 138

TitaniumTitanium

Bright white metal that burns in airBright white metal that burns in air Only element that burns in nitrogenOnly element that burns in nitrogen Melting point of about 3,500Melting point of about 3,500ºFºF Most important compound titanium dioxideMost important compound titanium dioxide

Used extensively in welding electrode Used extensively in welding electrode coatingscoatings

Used as stabilizer in stainless steelUsed as stabilizer in stainless steel

22 - 139

ZirconiumZirconium

Bright gray metalBright gray metal Melting point above 4,500Melting point above 4,500ºFºF Very hard and brittle and readily scratches Very hard and brittle and readily scratches

glassglass Used in hard-facing materialsUsed in hard-facing materials Often alloyed with iron and aluminumOften alloyed with iron and aluminum Argon or helium-argon mixtures used for Argon or helium-argon mixtures used for

gas shieldinggas shielding

140

ER70S-XElectrodeRod70,000 psi Min. Tensile StrengthSolidChemistry, Amount of Deoxidizers (Silicon, Manganese and/or Aluminum, Zirconium and Titanium) X=2,3,4,6,7 or G

AWS Classification of AWS Classification of GMAW ElectrodesGMAW Electrodes

143

GMAW Lesson #1GMAW Lesson #1 Objective: To run a stringer (straight) bead using short arc transfer and to fill the Objective: To run a stringer (straight) bead using short arc transfer and to fill the

cratercrater Equipment:Equipment:

Single Process - Constant Voltage Power Source & Wire Feeder Single Process - Constant Voltage Power Source & Wire Feeder • Power MIG 215 or Power MIG 255CPower MIG 215 or Power MIG 255C

Multi-Process Multi-Process • Composite: Power MIG 350 MPComposite: Power MIG 350 MP• Combination: V-350/ LF-72 packageCombination: V-350/ LF-72 package

Material:Material: Mild Steel Plate – 3/16” or thicker Mild Steel Plate – 3/16” or thicker

• .035” SuperArc L-56 (ER70S-6).035” SuperArc L-56 (ER70S-6)• 100% CO2 or 25% CO2/ 75% Argon blend shielding gas100% CO2 or 25% CO2/ 75% Argon blend shielding gas

144

GMAW Lesson #2GMAW Lesson #2 Objective: To make a fillet weld on a lap joint in the horizontal position (AWS Objective: To make a fillet weld on a lap joint in the horizontal position (AWS

position 2F)position 2F) Equipment: Equipment:


Multi-Process Multi-Process • Composite: Power MIG 350 MPComposite: Power MIG 350 MP• Combination: V-350/ LF-72 package Combination: V-350/ LF-72 package

MaterialMaterial Mild Steel Plate – 10 gaugeMild Steel Plate – 10 gauge .035” SuperArc L-56 (ER70S-6).035” SuperArc L-56 (ER70S-6) 100% CO2 or 25% CO2/ 75% Argon blend shielding gas100% CO2 or 25% CO2/ 75% Argon blend shielding gas

2F

145

GMAW Lesson #3GMAW Lesson #3 Objective: To make a fillet weld on a tee joint in the horizontal position Objective: To make a fillet weld on a tee joint in the horizontal position

(AWS position 2F)(AWS position 2F) Equipment: Equipment:


Multi-Process – Multi-Process – • Composite: Power MIG 350 MPComposite: Power MIG 350 MP• Combination: V-350/ LF-72 package Combination: V-350/ LF-72 package

Material: Material: Mild Steel Plate – 10 gaugeMild Steel Plate – 10 gauge .035” SuperArc L-56 (ER70S-6).035” SuperArc L-56 (ER70S-6) 100% CO2 or 25% CO2/ 75% Argon blend shielding gas100% CO2 or 25% CO2/ 75% Argon blend shielding gas

2F

146

GMAW Lesson #4GMAW Lesson #4 Objective: To make a fillet weld on a lap joint in the vertical position welding Objective: To make a fillet weld on a lap joint in the vertical position welding

down (AWS position 3FD)down (AWS position 3FD) Equipment: Equipment:




3FD

147

GMAW Lesson #5GMAW Lesson #5 Objective: To make a fillet weld on a tee joint in the vertical position welding down (AWS Objective: To make a fillet weld on a tee joint in the vertical position welding down (AWS

position 3FD)position 3FD) Equipment: Equipment:




3FD

148

GMAW Lesson #6GMAW Lesson #6 Objective: To make a butt weld with a gap in the vertical position Objective: To make a butt weld with a gap in the vertical position

welding down welding down Equipment: Equipment:



Material:Material: Mild Steel Plate – 10 gaugeMild Steel Plate – 10 gauge .035” SuperArc L-56 (ER70S-6).035” SuperArc L-56 (ER70S-6) 100% CO2 or 25% CO2/ 75% Argon blend shielding gas100% CO2 or 25% CO2/ 75% Argon blend shielding gas

3G

149

GMAW Lesson #7GMAW Lesson #7 Objective: To make a fillet weld on a tee joint in

the overhead position (AWS position 4F) Equipment:

– Single Process - Constant Voltage Power Source & Wire Feeder

Power MIG 215 or Power MIG 255C– Multi-Process –

Composite: Power MIG 350 MP Combination: V-350/ LF-72 package

Material: – Mild Steel Plate – 10 gauge– .035” SuperArc L-56 (ER70S-6)– 100% CO2 or 25% CO2/ 75% Argon blend

shielding gas

4F

150

GMAW Lesson #8GMAW Lesson #8 Objective: To make a three pass fillet weld on a tee Objective: To make a three pass fillet weld on a tee

joint in the horizontal position (AWS position 2F)joint in the horizontal position (AWS position 2F) Equipment: Equipment:

Single Process - Constant Voltage Power Source Single Process - Constant Voltage Power Source & Wire Feeder & Wire Feeder

• Power MIG 215 or Power MIG 255CPower MIG 215 or Power MIG 255C Multi-Process – Multi-Process –

• Composite: Power MIG 350 MPComposite: Power MIG 350 MP• Combination: V-350/ LF-72 package Combination: V-350/ LF-72 package

Material:Material: Mild Steel Plate – ¼”Mild Steel Plate – ¼” .035” SuperArc L-56 (ER70S-6).035” SuperArc L-56 (ER70S-6) 100% CO2 or 25% CO2/ 75% Argon blend shielding gas100% CO2 or 25% CO2/ 75% Argon blend shielding gas

2F

151

GMAW Lesson #9GMAW Lesson #9 Objective: To run a horizontal fillet weld on a tee joint using axial Objective: To run a horizontal fillet weld on a tee joint using axial

spray transfer (AWS position 2F)spray transfer (AWS position 2F) Equipment: Equipment:

Single Process - Constant Voltage Power Source Single Process - Constant Voltage Power Source & Wire Feeder & Wire Feeder

• Power MIG 225CPower MIG 225C Multi-Process – Multi-Process –

• Composite: Power MIG 350 MPComposite: Power MIG 350 MP• Combination: V-350/ LF-72 package Combination: V-350/ LF-72 package Material: Material:

Mild Steel Plate – ¼” Mild Steel Plate – ¼” .045” SuperArc L-56 (ER70S-6).045” SuperArc L-56 (ER70S-6) 90% Argon/ 10% CO2 blend shielding gas90% Argon/ 10% CO2 blend shielding gas

2F

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