GAS METAL ARC WELDING (GMAW)
GMAW is abbreviation for Gas shielded Metal Arc Welding. Here fusion is achieved by an electric arc formed between work piece and process is called MAG welding. The wire may be solid wire or flux cored wire. When the flux cored wire is used for welding, the process is called FCAW.
The welding can be semi automatic or mechanised. This is highly amenable for robot welding or robot manipulation. Generally, a constant potential type of power source is used. This may be a transformer-rectifier, thyristor controlled, transistor controlled or inverter type of power source, which may be chosen depending on the quality requirement Generally, in both GMAW and SAW processes, welding wire is connected to positive polarity of the power supply.
GMA welding is gradually replacing SMAW and GTAW. Most metals can be easily welded including aluminium, carbon steels, stainless steels, low alloy steels, nickel, copper, magnesium and titanium. More than 65 % of the welding carried out in developed countries is done by this process. In India as much as 30 % of the welding is by MIG / MAG welding, and nearly 65 % of the welding is by SMAW only.