6 BASIC WELDING GUIDE
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© ESAB AB 2021
6
BASIC WELDING GUIDE
6.1
MIG
(GMAW/FCAW)
basic
welding
Two different welding processes are covered in this section GMAW and FCAW, to provide the
very basic concepts in using the MIG mode of welding, where a MIG gun is handheld and the
electrode (welding wire) is fed into a weld puddle, and the arc is shielded by an inert welding
grade shielding gas or inert welding grade shielding gas mixture.
Gas
metal
arc
welding
(GMAW)
This process, also known as MIG welding, CO2 welding, micro wire welding, short-arc welding,
dip transfer welding, wire welding etc. is an electric arc welding process which fuses 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 or
welding grade shielding gas mixture. 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.
Figure 38: GMAW process
1 Solidified weld metal
5 Electrode
2 Molten weld metal
6 Arc
3 Shielding gas
4 Nozzle
7 Base metal
Flux cored arc welding (FCAW):
This is an electric arc welding process which fuses 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
the 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. 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.
1 Solidified weld metal
6 Nozzle (optional)
2 Slag
7 Flux cored electrode
3 Molten slag
8 Arc
4 Molten metal
9 Base metal
5 Shielding gas (optional)
