GMAW(MIG)-

THE MACHINE USED FOR GMAW IS A CONSTANT VOLTAGE,RECTIFIER TYPE MACHINE THAT PRODUCES DIRECT CURRENT ONLY.IT IS A 3 PHASE MACHINE

TYPE OF CURRENT-

DCEP(REVERSE POLARITY)

DCEN(STRAIGHT POLARITY) CAN BE USED WITH SPECIALY COATED WIRE.

WIRE FEEDER-

THE WIRE FEEDER CONTROLS THE AMOUNT OF WIRE FEED,THE WELDING CURRENT(AMPERAGE)AND THE FLOW OF SHIELDING GAS.THE WIRE FEEDER CAN BE MOUNTED ON A TRACK ,SWINGING BEAM ETC.

DRIVE ROLLS-

THERE A 4 DIFFERENT DRIVE ROLLS

1-V-GROVE-FOR HARD WIRE

2-U GROVE-FOR SOFT CORED WIRES

3-U COG ROLLS-FOR EXTREMLY SOFT WIRE

4-V KNURELED ROLLS-FOR HARD SHIELED CORE WIRES

WELDING WIRE-

SELECTION OF WELDING WIRE IS VERY IMPORTANT.IN MOST CASES THE WIRE IS CHOSEN TO MATCH THE BASE METAL AS CLOSELY AS POSSIBLE TO IMPROVE WELDABILITY.

SOLID AND TUBULAR WIRE IS USED FOR GMAW AND SUBMERGED ARC WELDING.

SOLID WIRE-MOST SOLID WIRE HAS A THIN COPPER COATING ON IT.THE COPPER IMPROVES THE CURRENT PICKUP BETWEEN THE CONTACT TIP AND THE WIRE.IT ALSO PREVENTS IT FROM RUSTING WHERE EXPOSED TO THE ATMOSPHERE.

NUMBERING SYSTEM-THE NUMBERING SYSTEM THE A.W.S. USES TO IDENTIFY SOLID WIRE IS E70S-1.THE SUFFIX NUMBER CAN GO UP TO 7.

E-ELECTRODE

R-ROD

70-TENSILE STRENGH IN PSI

S-INDICATES SOLID WIRE(T-FOR TUBULAR WIRE)

-1-INDICATES THE CHEMICAL COMPOSITION OF THE WIRE

SHIELDING GASES-

THE PURPOSE OF THE SHIELDING GAS IS TO KEEP THE MOLTEN PUDDLE FROM BEING CONTAMINATED FROM GASES IN THE ATMOSPHERE.SELECTION OF SHIELDING GAS IS IMPORTANT.

-O2 IMPROVES PENETRATION,ELIMINATES UNDERCUT AND HAS MINIMAL SPATTER

-C02 INCREASES SPATTER,OXIDES,INCREASES PENETRATION AND IS LOW IN COST

-HYDROGEN INCREASES HEAT,NOT RECOMMENDED FOR LOW ALLOY STEELS,BUT IS GOOD FOR NICKEL OR NICKEL ALLOYS AND HEAVIER STAINLESS STEEL.

INERT GASES-GASES THAT WILL NOT MIX WITH OTHER ELEMENTS.

ARGON AND HELIUM-ARE ONLY USED BECAUSE THE OTHER INERT GASES ARE MUCH TOO EXPENSIVE AND NOT AS AVAILIBLE

ADDITION OF -

ARGON-SMOOTH,MAXIMUM PENETRATION,NARROW BEAD MINIMAL SPATTER

HELLIUM-RAISES ARC VOLTAGE,GOOD FOR OVERHEAD AND HEAVY ALUMINIUM.

COOGAR2     95%ARGON/5%02

COOGAR3    98%ARGON/2%02

COOGAR4   80%ARGON/20%C02

COOGAR25 75%ARGON/25%C02

COOGAR    95%ARGON/2%O2/3%CO2

MEGA         25%ARGON/75%HELIUM

MEGA3      90%HELIUM/9.5%ARGON/2.5%CO2

SHORT CIRCUIT-

WIRE SIZES-.030,.035,.045

AMPERAGE-30-150AMPS,50-200IPM(INCHES PER MINUTE)

VOLTAGE-13-23VOLTS

SPRAY TRANSFER-MUST HAVE ARGON 90%

VOLTAGE-23-33VOLTS

AMPERAGE-170-300AMPS,300-450IPM

THERE IS MORE INFORMATION ON THIS SUBJECYT THAT I WILL BE ADDING SOON