Page 97 - Module DMV20173

5. 0 JOINING PROCESSES

5.2.5 GAS TUNGSTEN-ARC WELDING (GTAW)

1. Gas Tungsten-arc Welding (GTAW) also called Tungsten Inert Gas (TIG) welding.
Figure 5.6 shows the GTAW process and equipment for gas tungsten-arc-welding

operations.
2. The Tungsten Inert gas (TIG) system uses a non-consumable electrode of tungsten
and also provides an inert gas shield of argon or helium.
3. An arc is truck between a tungsten electrode (non-consumable) and the sheet metal

to be welded. The tungsten electrode is not consumed because of its extremely high
melting point.
4. An inert gas, Typically Ar or He shields the arc from the ambient to prevent oxidation
and contamination on molten metal.

5. A filler material is optional; depending on the type of weld and the thickness of weld,
generally bare wire, and electrode size range from 1.6 mm to 5.0 mm. However, it is
not usually required for thin material.
6. Carbon steels, low alloy steels, stainless steels, most aluminium alloys, zinc based
copper alloys can be welded using this process.

7. TIG is quite suitable for welding dissimilar materials, but usual cautions of galvanic
corrosion still apply.
8. The TIG process is a slower process compared to the MIG process, but the quality of
weld is cosmetically better.

EXERCISE 5.1

Describe the characteristics of Gas Tungsten Arc Welding (GTAW).

BPLK 129 DMV 20173