Tig Welding-Its Basics and Advantages & Disadvantages
Tungsten inert gas welding (TIG welding) belongs to the group of fusion welding processes and is characterized by particularly clean processing, high seam quality and almost universal applicability in the field of metals.
Due to the particularly precise coordination of the welding current with the respective welding task, the welding process is particularly suitable for root passes and constrained positions. For this reason, TIG welding is very popular for tasks with high demands on precision and seam quality, for example in pipeline and apparatus construction as well as in power plant construction and in the chemical industry.
Technical basics for TIG welding
The TIG welding process is based on the generation of an electric arc between the workpiece and an electrode made of tungsten. In addition, an inert gas such as argon or helium is used to protect the arc from external influences.
TIG welding functionality
Compared to other welding processes such as MIG or MAG welding, TIG welding is primarily characterized by the fact that the tungsten electrode used does not melt during welding, but is retained. Instead, a filler metal is used as required to create a seam between the workpieces to be joined. This filler material is usually a welding wire that is held at the contact point of the two workpieces and melts there.
The structure of a TIG welding system
A TIG welding system essentially consists of a gas supply, a power source, a hose package, the torch and the negative pole. The power source is responsible for generating the voltage required to ignite the arc. In the past, short-circuit-based contact ignition was often used, today high-frequency ignition has become established. A high-voltage pulse generator is used to generate the high voltage required and to ionize the gas between the electrode and the workpiece. This procedure results in a safer and more efficient ignition process.
The hose package is not only responsible for the conduction of the welding current, but also contains the guidance of the shielding gas and the control line. With larger burners, it is also necessary to set up a cooling system to dissipate the process heat. In this case the hose package also contains the flow and return of the cooling water.
Areas of application for TIG welding
TIG welding is mainly used in applications where the demands on the quality and appearance of the weld seam are very high. These include the following areas of application:
Pipeline and apparatus construction
Power plant construction
Chemical industry
Medical technology
Bicycle frame construction
Aerospace Engineering
Railing construction
steel construction
Which shielding gas is used?
In TIG welding technology, the shielding gas is responsible for protecting and stabilizing the electric arc from the effects of oxygen. The gas thus represents an important basis for the quality of the weld seams.
When selecting the protective gas, it is important that it is an inert gas. Inert gases do not enter into any chemical reactions with the materials involved and are therefore ideally suited for use in welding processes.
Due to its inexpensive procurement, the noble gas argon is particularly popular in TIG welding. For applications with a high level of heat input, helium or a mixture of helium and argon is also used. If particularly high speeds are desired during welding, hydrogen can also be added in small quantities.
When supplying protective gas, it is important to determine a suitable flow rate. The flow rate depends not only on the material, but also on the desired shape of the weld, the welding position and the diameter of the gas nozzle.
What are the advantages and disadvantages of TIG welding?
The advantages and disadvantages of the TIG welding process at a glance:
Advanatages:
Suitable for all weldable metals
Precise addition of welding wire thanks to the non-melting tungsten electrode
No slag formation thanks to inert gas
Hardly any material deformation
Suitable for all welding positions
Disadvantages
High susceptibility to wind, therefore not suitable for outdoor areas
High energy demand
High initial investment