Two different welding processes are covered in this section
(GMAW and FCAW), with the intention of providing the very basic
concepts in MIG welding, where a welding gun is hand held, and
the electrode (welding wire) is fed into a weld puddle, and the arc
is shielded by a gas (GMAW) or flux cored wire (FCAW).
Gas Metal ARC Welding (GMAW)
This process, also known as MIG welding, CO
2
welding, Micro
Wire Welding, short arc welding, dip transfer welding, wire
welding etc., is an electric arc welding process which fuses
together the parts to be welded by heating them with an arc
between a solid continuous, consumable electrode and the work.
Shielding is obtained from an externally supplied welding grade
shielding gas. The process is normally applied semi automatically;
however the process may be operated automatically and can be
machine operated. The process can be used to weld thin and
fairly thick steels, and some non-ferrous metals in all positions.
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BASIC MIG WELDING GUIDE
11
MULTIMIG 200 PFC MV
OWNER’S MANUAL
Flux Cored Arc Welding (FCAW)
This is an electric arc welding process which fuses together
the parts to be welded by heating them with an arc between a
continuous flux filled electrode wire and the work. Shielding is
obtained through decomposition of the flux within the tubular
wire. Additional shielding may or may not be obtained from an
externally supplied gas or gas mixture. The process is normally
applied semi automatically; however the process may be applied
automatically or by machine.
The angle of MIG torch to the weld has an effect on the width of
the weld.
The welding gun should be held at an angle to the weld joint.
(See Secondary Adjustment Variables below).
Hold the gun so that the welding seam is viewed at all times.
Always wear the welding helmet with proper filter lenses and use
the proper safety equipment.
CAUTION
Do not pull the welding gun back when the arc is
established. This will create excessive wire extension
(stick-out) and make a very poor weld.
The electrode wire is not energized until the gun trigger switch
is depressed. The wire may therefore be placed on the seam or
joint prior to lowering the helmet.
It is commonly used to weld large diameter electrodes in the
flat and horizontal position and small electrode diameters in all
positions. The process is used to a lesser degree for welding
stainless steel and for overlay work.
