Just like submerged-arc welding, gas-shielded arc welding is also an electric fusion process.
The weld is produced by electric arcs. The arc is most notable as it burns between the electrode and work-piece. This means that the arc, electrode, and weld pool are all protected from the atmosphere by shield or inert protective gas which is constantly being fed into the atmosphere during this process.
This process and others alike are classified according to the type of electrodes and gas employed.
-Gas Tungsten arc Welding
Tungsten inert gas welding (TIG)
Tungsten Plasma arc welding (TP)
Tungsten Hydro Arc welding (THG)
-Gas metal Arc Welding
Metal inert Gas Welding (MIG)
Metal Active Gas Welding (MAG)
Processes that are predominantly serviced for tube and pipe manufacturing are TIG, MIG, and MAG methods.
TIG and MIG welding processes are used mainly in the stainless steel industry. In TIG welding the arc burns between a non-melting electrode and the work-piece. Filler metal is fed to the predominantly without direct current input. The gas shield is fed from a nozzle protecting electrodes and filler metal from contacting the atmosphere.
The shield gas is inert, usually takes form of argon, helium, or a mixture of both.