Applications:

The gas tungsten arc welding process is utilized with welding currents from 0.5 A up to 700~800 A and is one of the most versatile procedure of welding. The lowest currents are utilized with delicate air-cooled torches, to weld metal 0.05 mm thick. For these very low currents DCEN is typically used. A.C. is employed among 25 and 350 A, but above this current the risk of tungsten inclusions enhanced. Up to 800 A, DCEN is again utilized and these high currents are employed specifically for welding thick copper. Torches designed for up to approximate 100 A are completely air cooled but for higher currents water-cooled torches ought to be used.

Although high welding currents permitting the welding of thick metal are possible, tungsten-arc welding is primarily a procedure for welding sheet metal or small parts. The procedure is at its best while welding single-pass or double-sided close butt joints, edge-joints or outside corner-joints. This is less appropriate for fillet welds with which care must be taken to attain good fusion into the root. Because it is so easily mechanised and gives high quality welds, the process is wholly favoured for precision welding in the aircraft, atomic energy and instrument industries. Circumferential and edge welds, for instance, can-sealing joints, are very appropriate for mechanised tungsten-arc welding. Arc-length control systems are sometimes utilized with mechanised welding in which the arc voltage provides a signal to move up or lower the welding head so that the arc might follow a curved or undulating surface.

Many automatic devices are available for welding tubes to tube-plates. Typical of these is the method in which a miniature torch revolves around a central spigot i.e. fitted into the tube.