A couple primary reasons. 1 the current reversing itself helps to break up oxides on the surface of the metal. 2 Alternating current produces more heat in the arc which is useful in welding aluminum...
The tungsteng electrode, because this one not is a filler metal in this process. The individual may be asking what metal can you not weld using the TIG process. In that case cast iron, zinc...
for giving the heat to rod and make joint easily. if you are referring to Tig welding or GTAW as you call it in America the amperage depends on the thickness of metal the thicker the metal the higher...
in welding sometimes your electrode got stuck to your work piece so a very high current would flow and no voltage at generator teminals. only a small voltage will produce in the armature due the...