Process Description:

The Gas Tungsten Arc Welding procedure is illustrated in Figure 5. The procedure uses a non-consumable tungsten (or tungsten alloy) electrode held in a torch. Shielding gas is fed be means of the torch to defend molten weld pool  ,the electrode,  and solidifying weld metal from contamination by the atmosphere. The most significant component of all TIG equipment is the high frequency (HF) unit by means of which high-frequency high-voltage is superimposed on the welding current. Because of this the shielding gas (argon, helium or their mixture) gets ionised. The electron that becomes free during the process of ionisation form a conducting path among the workpiece and the tungsten electrode. Therefore the arc can be begun without touching directly the tungsten electrodes to the workpiece. Beginning the arc by touching the tungsten electrode to the workpiece ought to be avoided as it contaminates and wears out the electrode tip, and gives increase to tungsten inclusions in the weld deposit, so degrading the weld metal properties. The arc might be maintained by keeping the HF unit on throughout the welding operation. Heat produced by the arc melts the base metal. Once weld pool and the arc are recognized, the torch is moved along the joint and the arc progressively melts the faying surfaces. Filler wire, if utilized, is usually added up to the leading edge of the weld pool to fill the joint. So some of the necessary components of TIG equipment are following:

1.      Torch,

2.      Electrode,

3.      Welding power source, and

4.      Shielding gas processes.