GTAW parameters and arc welding process
Known as GTAW process, as the commercial welders call it, the gas tungsten arc welding process was created back in the 1940s when it was necessary for aluminum and magnesium alloys to be welded for the use of the aircraft industry and applications.
The gas tungsten arc welding process was developed as a new method of welding as it was necessary for welding to be done on these materials in a better way than the SMAW or the shielded metal arc welding process. Nowadays, the commercial welders are using the GTAW welding process when they have to weld precision parts such as metal bellows, batteries, various medical components, pacemakers, different surgical tools, etc.
In the beginning, the commercial welders were using the helium as the shielding gas and thus they named the welding process ‘heliarc welding’. Then the helium was replaced by the argon, which became the most widely spread and used shield gas in the welding industry thanks to its smooth arc and to its low cost.
During the gas tungsten arc welding process the electrical arc is established between the part that has to be welded and the tungsten electrode. In order for the arc to start, the commercial welder performing the process has to use high voltage in order to break down the insulating gas that is formed between the part and the electrode. Then the current is transferred through the electrode and it forms an electrode arc. Then the metal that is subject of the welding is melted by the strong arc heat and fuses with the filler material.
After that the arc zone is filled with inert gas. The experienced commercial welder does that in order to protect the molten material and the tungsten electrode from possible oxidation and to offer a path for the arc current. The shield gases that are used in the gas tungsten arc welding process include helium and argon, as well as a mixture of both, as well as mixtures with small amounts of hydrogen and argon. In general, the commercial welder is the one who chooses the shield gas depending on the material that has to be welded.