Gas Tungsten Arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by an inert shielding gas (argon or helium), and a filler metal is normally used.
GTAW is used to produce a homogenous and low dilution weld overlay of various materials over Mild Steel and Stainless Steel substrates. Some of the materials deposited with GTAW are as follows :
The process can also be automated with PLC controlled manipulator and a voltage feedback (AVC) which senses the voltage and corrects the torch distance. Using Auto-GTAW a uniform overlay can be achieved and process completion time can be reduced significantly.
After desired thickness is achieved the coating is further re-heated and taken to solidus temperature (1020 to 1100 ºC).At this temperature coating fuses and voids and porosity in the coating collapses making the coating more dense and homogeneous. This also forms a fine metallurgical bond with the prepared substrate which makes the coating capable of enduring impacts.