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TIG welding

Joining process which creates an electric arc through the use of a tungsten electrode. This is protected by an inert gas and a filler material is supplied optionally.

Illustration of TIG welding

The process

The method can be used with or without filling materials [1]. What determines the need for the filling material is particularly workpiece thickness.

An inert gas [2], typically consisting of argon, is supplied with the intention to protect both the tungstens electrode [3] and the melt from oxidation.

The electrode and the workpiece is coupled to an external power source. As a rule, an alternating current source of high frequency to cyclically remove an oxide layer is created, but also so that it facilitates electrode penetration and cooling. However, this depends on the choice of processing materials. When the electrode is brought close to the workpiece an arc is created [4], which heats the material and results in the finally melts at the contact point.

A possible filling is continuously fed to the contact point.

Depending on the need of automation, the method can be performed either manually or automatically. The manual method requires the manual control of both the torch and the optionally added filler. The automatic method uses instead an automatic control of torch and also the added filler material can be fed automatically. In automated welding, the protective gas is replaced with helium in order to achieve a higher temperature and this can generate a more efficient process.