The torch also uses a secondary gas, argon, argon/hydrogen or helium which assists in shielding the molten weld puddle thus minimizing oxidation of the weld. By forcing the plasma gas and arc through a constricted orifice, the torch delivers a high concentration of heat to a small area.
Argon also provides a smooth, stable arc. It envelops and stabilizes the electrical current of the TIG welding torch to keep the metals from becoming oxidized. Furthermore, it assists in the clean finish of weldments.