Basic Welding: Gas Tungsten Arc Welding

Tungsten Inert Gas (TIG) Welding




Overview: In the TIG process the arc is formed between a pointed tungsten electrode and the workpiece in an inert atmosphere of argon or helium. The small intense arc provided by the pointed electrode is ideal for high quality and precision welding. Because the electrode is not consumed during welding, the welder does not have to balance the heat input from the arc as the metal is deposited from the melting electrode. When filler metal is required, it must be added separately to the weldpool.
Applications of TIG welding : TIG is applied in all industrial sectors but is especially suitable for high quality welding. In manual welding, the relatively small arc is ideal for thin sheet material or controlled penetration (in the root run of pipe welds). Because deposition rate can be quite low (using a separate filler rod) MMA or MIG may be preferable for thicker material and for fill passes in thick-wall pipe welds.
Hazards in GTAW welding: All hazards related to MMA welding are always applicable to TIG welding also. In addition the following hazards are present in TIG welding:
a) Asphyxia: TIG welding involves use of inert gases to protect weld pool form atmosphere. When this process is used in confined spaces, it may lead to asphyxiation. Welders have to be cautious about ventilation available to them.
b) Leakage of water, short circuit, hot water bath: This process uses water to cool the tungsten electrodes. This water is circulated by a pump & is recycled through a tank. For some reasons if the water circuit is jammed or level of water in the tank is insufficient, the PVC pipes carrying water may burst, giving the welder a hot water bath. Also leaks through pump & tank may interfere with the electric circuits causing short circuits.