TIG (tungsten inert gas) – is a method of welding with a non-fusible tungsten electrode in a shield of inert gases such as helium, argon, or a mixture of these gases, and the welded material. The method is coded 141.
The arc glows between the material to be welded and an electrode made of tungsten or an electrode made of tungsten with additives (lanthanum, cerium, thorium,). The welding pool is shielded by a protective atmosphere, usually pure argon. The welded joint can be made without additional material, by mixing the superfused edges of the parts to be joined, or with the participation of additional material in the form of a rod added to the welding pool. The arc is ignited by two methods. The touch method by touching the tungsten electrode to the weld material and then raising it a few millimeters (TIG Lift), or the non-contact method using an ionizer (TIG HF).In the vast majority of cases, the “ground” terminal is attached to the positive pole (plus) of the welder, and the tungsten electrode (TIG torch) is attached to the negative pole (minus). As a result, this causes an increased amount of heat to be released at the weld area, rather than at the electrode (electrons flow from minus to plus).
Application:
The TIG method is used for automatic or manual welding. Welded by this method are all steels, non-ferrous metals, especially alloy steels, high-alloy steels, the welding itself is carried out with direct current (DC),.
With the use of alternating current (AC), the main application is the joining of aluminum, aluminum alloys and other materials that form a difficult-to-melt oxide on the surface as a result, better joints are obtained than with gas welding.
The most commonly used technological parameters:
– in continuous or pulsed mode intensity from 5-600 A
– 10-30 V voltage
– 0.12-0.21 m/min welding speed
– 0.5-6.4 mm electrode diameter
– 7-20 l/min protective gas flow rate
Advantages:
– Quality of connections the best of all welding methods
– The possibility of automating the process (robotization)
– wide range of welding of parts of different thicknesses (the only method for surfacing and artistic welding of parts less than 1 mm thick; only in pulse mode with a guiding arc for better targeting of the weld area)
– welding possible in all positions
Disadvantages:
– in the case of manual welding low productivity (weld quality compensation)
– When welding in the open space, there is a need for additional wind shielding
