Gas metal arc welding (GMAW), also known as MIG (metal inert gas) welding or MAG (metal active gas) welding, is a process in which an electric arc forms between an electrode and a metal workpiece, heating the metals and causing them to melt, and be joined.
The weld area is generally protected from atmospheric contamination by use of an inert shielding or cover gas (argon or helium).
The term "Industrial Gases" refers to gases which are produced in relatively large quantities by industrial gases companies for use in a variety of industrial manufacturing processes. They are produced and supplied in both gas and liquid form. They are transported to customers in cylinders, as bulk liquid, or as pipeline gases.
Common atmospheric gases: Nitrogen, Oxygen and Argon
Air-derived "rare gases": Neon, Krypton and Xenon
Natural gas-derived gases: Methane and Helium
Products from methane reforming:Hydrogen, Carbon monoxide, Carbon dioxide
The major difference between MIG and TIG is that one process uses a continuously feeding wire (MIG) and the other you use long welding rods and slowly feed them into the weld puddle (TIG). The technical names for these are metal inert gas (MIG), and tungsten inert gas (TIG).