The essence of MIG-MAG processes is the metal wire, which is fed automatically to the welding area via the welding gun and melted in the arc. In this sense MIG-MAG processes are often called semi-automatic welding, as the welding have to move the burner along the weld manually. The wire, which is used in this process, has two functions. It is both a conducting electrode and an additive. The result (quality) of MIG-MAG process application depends mainly on the proper selection of welding machine operating mode (arc voltage, current= wire feed speed, welding speed) and the choice and flow of shielding gas (the rate of its supply to the nozzle). It is reasonable to use gas regulators with float-type flow meters to control shielding gas flow.
Shielding gas, which is fed to the welding area via a nozzle, protects the arc and the pool with melted metal. Melted metal is reactive and it may react with shielding gas. Inert shielding gas, e.g. argon or helium, does not react with the metal in the pool during arc burning. Active shielding gases are carbon dioxide and argon mixtures (or helium, which is used rarely) with some carbon dioxide or oxygen. Until recently carbon dioxide was the most widely applied shielding gas for semi-automatic welding processes.
Certified CORGON (Ar+CO2) welding mixtures are the most advanced shielding gases for steel welding as they provide benefits compared to conventional carbon dioxide both in terms of quality and reliability of welds, welding efficiency etc.
MIG-MAG process may be used for welding of both low and high alloy (stainless) steels, aluminum and their alloys. A relatively new MIG-MAG process application field is the high-capacity MIG-MAG soldering in shielding gas. This process may be used with different metal combinations, i.e. iron-iron, copper-copper, copper-iron etc.