 GTAW can be used on nearly all weldable metals , though it is most often applied to stainless steel and light metals . It is often used when quality welds are extremely important , such as in bicycle , aircraft and naval applications . A related process , plasma arc welding , also uses a tungsten electrode but uses plasma gas to make the arc . The arc is more concentrated than the GTAW arc , making transverse control more critical and thus generally restricting the technique to a mechanized process . Because of its stable current , the method can be used on a wider range of material thicknesses than can the GTAW process and it is much faster . It can be applied to all of the same materials as GTAW except magnesium , and automated welding of stainless steel is one important application of the process . A variation of the process is plasma cutting , an efficient steel cutting process . 
