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TIG Welding Machine
A shielding gas (argon, helium, or both) is used to avoid the atmospheric contamination of the molten metal weld pool. Filler metal may be added if required.
Principle of Operation
Welding current, inert gas supply, water is turned on. Electric arc is struck between the non-consumable electrode and the work piece by touching the electrode with work piece or using a high frequency until. In 1st method arc is initially struck on a scrap metal piece and then broken by increasing arc length.
In 2nd method a high frequency current is supper-imposed on the welding current. Welding torch is brought near to the job when electrode tip reaches within a distance of 3 to 2 mm from job. A spark jumps across the air gap between the electrode and job. Air path gets ionized and arc is established.
TIG welding is also known as Gas Tungsten Arc Welding Machine (GTAW) both the AC and DC power source can be used for GTAW electrode employed varies in dia from 0.5 to 6.5 mm carrying current from 5A to 650A; welding torch used for carrying current higher than 1000A is normally water cooled. GTAW is all position (1G, 2G, 3G, 4G.6G) welding and gives the highest quantity weld amongst commonly used arc welding process.
Equipment used in TIG Welding Machine
a) Welding torch, tungsten electrode and filler rod.
b) Welding power source, high frequency unit, DC suppressor unit and cables.
c) Inert gas cylinder for shielding purpose, pressure regulator, flow meter.
d) Cooling water supply.
e) Gas and water solenoid valve.
Advantage of TIG Welding Machine
a) TIG welding is very suitable for high quality welding of thin material.
b) Deeper penetration can be achieved through this process.
c) No flux is used so there is no danger of flux entrapment.
d) As this process can be seen with the help of goggle therefore operator can exercise a better control on the welding process.
e) TIG is very suitable for welding of non-ferrous metals and stainless steel.
f) TIG welding is suitable for welding in all positions (1G, 2G, 3G, 4G, 6G).
Limitations
a) MIG welding is much faster process as compared to TIG welding under similar application.
b) Tungsten if transfer to molten weld pool can contaminate the same.
c) Tungsten inclusion is hard and brittle.
d) TIG welding equipment is more costly as compared to other welding equipment.
e) Skill or trained operator is required for welding.
Application of TIG Welding Machines
a) Basically welding of aluminium, magnesium, copper, nickel and their alloys, carbon, alloys or stainless steel, high temperature and hard surfacing alloys such as zirconium, titanium etc.
b) Welding sheet metal and thinner section.
c) Precision welding in automatic energy aircraft chemical and instrument industries.
