Welding is a fabrication process that joins materials, usually metals, by causing fusion. In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that is usually stronger than the base material.
The welding methods used by HTF are:
Gas tungsten arc welding (GTAW) – also known as TIG (tungsten, inert gas), that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by an inert shielding gas such as argon or helium.
Resistance spot welding (RSW) as a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current typically for sheets that are in the 0.5 to 3 mm (0.020 to 0.118 in) thickness range clamping the sheets together.