AWS - GMAW Fundamentals

7/21/2019 AWS - GMAW Fundamentals

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GMAW FundamentalsGMAW Fundamentals

Gas Metal Arc Welding

Metal Inert Gas

By: Wanda Sue Benton

ESAB University & Florence-Darlington Tecnical !ollege


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IntroductionIntroduction

GMAW is de"ined as arc #elding using a

continuously "ed consu$a%le electrode and

a sielding gasGMAW is also 'no#n as MIG (Metal Inert

Gas)

*roduces ig-+uality #elds

,ields ig roductivity


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AdvantagesAdvantages

.arge gas "illed or %ridged easily

Welding can %e done in all ositions

/o slag re$oval re+uired

0ig #elding seeds

0ig #eld +uality.ess distortion o" #or' iece


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Types of Metal TransferTypes of Metal Transfer

Te %asic GMAW rocess includes tree

distinctive rocess tecni+ues:

1 Sort !ircuit (Sort Arc)

2 Glo%ular Trans"er

3 Sray Arc Trans"er


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

4erates at lo# voltages and #eldingcurrent

S$all "ast-"ree5ing #eld uddle o%tainedUse"ul in 6oining tin $aterials in any

osition7 as #ell as tic' $aterials in

vertical and overead ositionsMetal trans"er occurs #en an electrical

sort circuit is esta%lised


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Gloular TransferGloular Transfer

Welding current and #ire seed are

increased a%ove $a8i$u$ "or sort arc

Drolets o" $etal ave a greater dia$eter

tan te #ire %eing used

Satter resent

Welding is $ost e""ectively done in te "lat

osition #en using glo%ular trans"er


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Spray Arc TransferSpray Arc Transfer

4ccurs #en te current and voltage

settings are increased iger tan tat used

"or Glo%ular Trans"erUsed on tic' sections o" %ase $aterial7 %est

suited "or "lat osition due to large #eld

uddleSatter is $ini$al to none


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Manual GMAW !"uipmentManual GMAW !"uipment

Tree $a6or ele$ents are :

1) Welding torc and accessories

2) Welding control & Wire "eed $otor

3) *o#er Source

GMAW e+ui$ent can %e used eiter

$anually or auto$atically


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WI9E !4/T94.

&

WI9E FEED M4T49

*4WE9 S4U9!E


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Welding Torch # AccessoriesWelding Torch # Accessories

Te #elding torc guides te #ire and

sielding gas to te #eld 5one

Brings #elding o#er to te #ire also

Ma6or co$onentsarts o" te torc are te

contact ti7 sielding gas no55le7 gas

di""user7 and te #ire conduit


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T9IGGE9

I/STA..ED

!4M*4/E/TS

/4;;.E

!4/TA!T TI*

GAS DIFFUSE9


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Welding Control # WireWelding Control # Wire

Feed MotorFeed MotorWelding control & Wire "eed $otor are

co$%ined into one unit

Main "unction is to ull te #ire "ro$ te

sool and "eed it to te arc

!ontrols #ire "eed seed and regulates te

starting and stoing o" #ire "eed

Wire "eed seed controls A$erage


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WI9E FEEDE9


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$o%er Source$o%er Source

Al$ost all GMAW is done #it reverse olarityalso 'no#n as D!E*

*ositive (


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*4SITI=E

TE9MI/A.

/EGATI=E

TE9MI/A.


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Shielding GasesShielding Gases

*urose o" sielding gas is te rotect te#eld area "ro$ te conta$inants in te

at$osereGas can %e Inert7 9eactive7 or Mi8tures o"

%ot

Gas "lo# rate is %et#een 2>-3> !F0Argon7 0eliu$7 and !ar%on Dio8ide are te

$ain tree gases used in GMAW


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F.4W METE9

!,.!I/DE9

*9ESSU9E

GAUGE

!F0 *9ESSU9E

AD?USTME/T

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