Abstract
Effects of a constricted nozzle on the arc phenomena in Tungsten Inert Gas (TIG) welding process are investigated by numerical simulation. The obtained results show that the temperature and velocity of the arc plasma are increased by attaching an additional gas nozzle which is called "constricted nozzle". As a result, the iron vapor does not diffused upward but transported outward. In addition, the heat transfer to the base metal surface is enhanced.