Tungsten inert gas welding (TIG welding) is a gas shielded welding process and is one of the fusion welding processes. It is used wherever optimum quality and spatter-free weld seams are required. TIG welding is suitable, among other things, for stainless steels, aluminum and nickel alloys as well for thin sheet metal made of aluminum and stainless steel. It is used in pipeline and container construction, in portal construction and in aerospace applications.
In TIG welding, the required current is supplied via a tungsten electrode, which is temperature-resistant and does not melt. This electrode emits an arc that heats up and liquefies the material. There is a nozzle for shielding gas around the electrode. This protects the heated material from chemical reactions with the ambient air. The noble gases argon, helium or mixtures thereof are used for this purpose. The inert, i.e. non-reactive, gases prevent chemical reactions with the liquid weld pool and the heated material. This ensures high-quality weld seams.
As the tungsten electrode does not melt, in TIG welding the filler material is fed in by hand or in mechanized form by an external wirefeeder.
For Tig welding Argon is the most used gas but helium by itself, or mixed with argon, may be used for special applications. Argon-hydrogen mixtures can be used for austenitic stainless steel.
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