between the electrode and the workpiece. This is termed as a transferred
arc. The transfer arc flows through the nozzle and extends
its path to reach the base metal, forming a low resistance path of
current between the tungsten electrode and the base metal. The
plasma arc is with high temperature and velocity due to the restriction
by the orifice, fusing and joining the metal pieces as desired.
The plasma gas itself is not sufficient to protect the weld metal and
therefore, a large volume of inert shielding gas is allowed to flow
through an outer gas nozzle surrounding the inner nozzle,