tungsten inert gas welding process

Which  current is used in tungsten inert gas welding

 

tungsten inert gas 

TIG welding process wherein coalescence is produced by heating the job with an electric arc struck between a tungsten electrode and the job. Shielding gas is used to avoid atmospheric contamination of the molten weld pool.

Tungsten Welding Operation:

Welding current, water, and inert gas supply are turned on, and the arc is stuck either by touching the electrode with scrap metal. The arc is then struck between the electrode and precanceled job to be welded. The welding torch is brought near to the job. When the electrode tip reaches a distance of 3 to 2 mm from the job, a spark jumps across the air gap between the electrode and the job. The air path gets ionized and the arc is established.

 

TIG welding Construction and Working

Welding current, water, and inert gas supply arc turned on. The arc is

struck either by touching the electrode with scrap metal or then breaking by increasing the arc length. The procedure was repeated twice or thrice warming up the tungsten electrode. The arc is then struck between the electrode and precanceled job to be welded. This method avoids breaking the electrode tip, job contamination, and tungsten loss.

When the electrode tip reaches a distance of 3 to 2 mm from a job a spark jumps across the air gap between the electrode and the job. The air path gets ionized and the arc is established. After striking the arc, it is allowed to impinge on the job and a molten weld pool is created. The welding is started by moving the torch along the joint as in oxyacetylene welding. At the far end of the job, the arc is broken by increasing the arc length. The shielding is allowed to impinge on the solidified weld pool for a few seconds even after the arc is extinguished. This will avoid atmospheric contamination of the weld metal.

 

TIG welding Advantage

1)    No flux is used, hence there is no danger of flux entrapment.

2)    Because of the clear visibility of the arc and the job, the operator can exercise better control of the welding process.

3)    This process can weld in all positions and produce smooth and sound welds with fewer spatters.

4)    Tig welding is very much suitable for high-quality welding of thin materials.

5)    It is a very good process for welding nonferrous metals.

 

TIG welding Disadvantage

1)    Under a similar application MIG welding is a much faster process as compared to TIG welding, since TIG welding requires a separate filler rod.

2)    Tungsten if it transfers to a molten weld pool can contaminate the same. Tungsten inclusion is hard and brittle.

3)    Filler rod end if it by chance comes out of the inert gas shield can cause weld metal contamination.

4)    Equipment costs are higher than those for flux-shielded metal welding.

 

TIG weldingApplication

1)    Welding aluminum, magnesium, copper

2)    Welding sheet metal and thinner sections.

3)    Welding of expansion bellows, transistor cases, can seats, etc.
4)    Precision welding in atomic energy, aircraft chemical, and instrument industry.
5)    Rocket motor chamber fabrication in launch vehicles.