The TIG welding process stands for high quality welding and is used in demanding applications of pipeline welding, food industry, pressure vessels, aviation and many others.
In gas shielded tungsten arc welding (GTAW) or tungsten inert gas (TIG) welding, the electric arc is generated between a non-consumable tungsten based electrode and the base material under protection of an inert gas. The shielding gas is argon (Ar), helium (He) or argon/helium mixtures of high purity. The shielding gas cools and protects the heated tungsten electrode against oxidation by atmospheric oxygen and enables the formation of a stable electric arc. In addition the inert gas protects the liquid weld pool from the ambient air. In the GTAW process, the filler metal is applied manually by the welder or in mechanized processes by using a TIG wire feeder. In standard GMAW processes the TIG-rod or wire is used without electrical voltage. For the mechanized higher productivity Hot-TIG process the TIG-wire is electrically pre-heated.
TIG-rods of 500 mm, 36” (914 mm) or 1000 mm length are used as filler metals for manual welding. For mechanized processes wires of usually 0,8 to 1,2 mm are wound on spools of various diameters with 1 to 15 kg of weight. In general direct current is used with negative polarity on the tungsten electrode.
For a perfect GTAW result several parameters need to be considered for the tungsten electrode, like composition of the tungsten based electrode material, diameter, tip angle and shape or thermal load. The setting of welding parameters can be done according to standard tables or by using sophisticated welding machines supporting with intelligent functions such as Böhler Welding EasyArc.
The scope of application stretches from welding of thin sections of non and medium alloyed and stainless steel grades to high-quality root welding in thicker plates and tubes. GMAW is the process of choice for non-ferrous materials as aluminium, magnesium or copper alloys.