GTAW

Gas Tungsten Arc Welding (GTAW) also known by Tungsten Inert Gas (TIG) or HeliArc is a manual or semi-automatic welding process which uses a non-consumable tungsten electrode to produce an electric arc. An inert shielding gas is used to protect the weld pool from the atmosphere. Most often filler metal is added to the weld manually at the point of the weld pool, although some welds known as autogenous welds do not require it. GTAW requires a constant current welding power supply which produces an arc through a column of ionized gas and metal vapors known as plasma.

GTAW is commonly used to weld thin sections of stainless steel, aluminum, magnesium, and copper alloys. The process grants the welder greater control over the weld pool than competing processes such as GMAW and SMAW allowing for stronger, higher quality welds. GTAW is comparatively more complex and difficult to master than its competing processes, calling for high levels of skill to produce consistant high quality welds. It is also signifigantly slower than other processes. A related process called Plasma Arc Welding (PAW) uses a slightly different torch design to produce a more focused welding arc, and as a result is generally automated.

A drawing of the GTAW process: