In tungsten inert gas arc welding (TIG),
an arc is struck between a nonconsumable tungsten electrode and the
workpiece. Gas shielding (to protect the molten metal from
contamination) and constant amperage are supplied during the welding
operation.
Information provided is from Manufacturing Processes Reference
Guide by Robert H. Todd, Dell K. Allen, and Leo Alting.--1st ed. Published by
Industrial Press Inc., 1994.