Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW), is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an inert gas such as argon), and a filler is normally used. A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminum, magnesium and copper alloys. The process grants the operator greater control over the weld than competing processes such as shielding metal arc welding and gas metal arc welding, allowing for stronger, higher quality to master, and furthermore it is significantly slower than most other welding techniques. A related process, plasma arc welding uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.