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How does a TIG welder work?


How does a TIG welding machine work?

How does a TIG welding machine work?

When welding with a TIG welding machine, the current intensity and the amount of filler metal can be adjusted to the workpiece. In TIG welding, the filler metal is fed drop by drop or continuously. The welding rod always remains in the liquid weld pool, which is why TIG welding is also known as the “piercing method”.

Functions of TIG welding machines

A TIG welding machine consists of a power source, which can usually be switched to alternating or direct current welding, and a welding torch, which is connected to the power source by a hose package. The shielding gas equipment, the control cable and the welding current cable are located in the hose package of a TIG welding machine. There are two methods to ignite the arc: The high-frequency and contact ignition.

In the meantime, high frequency ignition has almost completely replaced string ignition.

High frequency ignition

In high-frequency ignition, the arc is ignited by means of a high-voltage pulse generator, which delivers a high voltage to the tungsten electrode, thereby ionising the gas between the workpiece and the electrode. Because the high-voltage pulse generator has a high internal resistance, no dangerous currents can be generated. When welding with a TIG welding machine, the noble gas argon is usually used. It is also possible to use helium, which is much more expensive, but is used to maximise the heat input due to its better thermal conductivity.

With and without additive

Welding with a TIG welding machine can be carried out with or without a filler material. As with gas fusion welding, so-called rod-shaped additives are usually used for manual welding. However, confusion with the gas welding rods should be avoided as far as possible, as the chemical compositions differ.


Direct and alternating current welding with a TIG welding machine

How does a TIG welding machine work?

The TIG welding method also distinguishes between direct and alternating current welding. Direct current welding with a negatively poled electrode is used for welding steel, non-ferrous metals and their alloys. In contrast, the alternating current welding method is mainly used for welding light metals such as aluminium or magnesium.

In individual cases, light metals are sometimes also processed with direct current and a positive electrode, whereby the special welding torches with a very thick tungsten electrode and helium as shielding gas are used. The positive polarity of the tungsten electrode is necessary for light metals, as these usually form a hard oxide layer with a very high melting point on the surface. TIG welding machines are mainly used for thin sheets of stainless steel or aluminium, but can also be used for welding normal steel sheets.

TIG welding machines are the ideal choice especially when there is a high demand on the quality of the weld seam.

Advantages of a TIG welding machine

The advantages of a TIG welding machine: When using the inert gases argon and helium, no slag is formed; fast welding with TIG welders ensures that the material is hardly deformed due to the short exposure to heat. TIG welders can be used in all positions.

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