Gas Tungsten Arc Welding:

Helium was elected to provide the essential shield because, at that time, this was the only readily available inert gas. The procedure has been called non-consumable electrode welding and tungsten inert gas (TIG) welding. Although, the AWS terminology for this procedure is gas tungsten arc welding, because shielding gas mixtures that are not inert can be utilized for certain applications.

As the early days of the invention, numerous improvements have been built to the procedure and equipment. Welding power sources have been built  specifically for the process. Some of provide pulsed dc & variable polarity ac welding power. Gas-cooled  and water-cooled torches were built up. The tungsten electrode has been alloyed with small amounts of active elements to amplify its emissivity; this has enhanced arc starting, arc constancy, and electrode life. Shielding gas mixtures have been recognized for improved welding performance. Researchers are currently pursuing further improvements, in such as areas like automatic controls, vision & penetration sensors, & arc length controls.