<P> Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld . The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas (argon or helium), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it . A constant - current welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma . </P> <P> 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 shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds . However, GTAW is comparatively more complex and difficult 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 . </P>

Tig welding the welding zone is shielded by an atmosphere of