To perform TIG welding successfuly, you need to correctly select and prepare the tungsten electrode. You cant use any tungsten electrode; the wrong tungsten electrode will not perform correct. Using a tungsten electrode with a small diameter can lead to issues because it cannot handle the high amount of electrical current necessary for good weld results.
If you use too much amps with a tungsten electrode with a small diameter, it will melt. Using a tungsten electrode with a large diameter isnt suitable for thin metal because the large tungsten electrode will introduce too much heat into the metal. The diameter of the tungsten electrode must be matched to the amperage you are using and the thickness of the metal being welded.
Choose and Prepare the Right Tungsten Electrode for TIG Welding
The different types of tungsten electrode has color codes associated with them because the different alloys of the tungsten electrodes look the same to the human eye. The alloys of the tungsten electrodes reacts differently to the electricity and heat used during welding. Pure tungsten electrode materials is used for welding aluminum.
However, zirconiated or rare earth tungsten electrodes is used more often because they handle heat better. Thoriated tungsten electrode are used for DC welding of steel because the thoriated tungsten electrodes start the arc easily and maintain a sharp point on the electrode. You cannot use the same type of tungsten electrode for each type of metal because the chemical composition of the tungsten electrodes change the way the arc reacts to the metal.
The shape of the tip of the tungsten electrode must be prepared correctly to TIG welding because the shape of the tungsten electrode determine the shape of the arc formed during TIG welding. If you are welding metals like steel or titanium, you will have to grind the tungsten electrode to form a sharp point on the electrode. You must grind the tungsten electrode longitudinal along its length.
You will get bad results if you grind the tungsten electrode in circular motions because this will form grooves on the tungsten electrode that will cause the arc to wander during welding. Aluminum metal will require a tungsten electrode with a rounded tip. The tungsten electrode must be matched with the base metal being welded together.
For example, welding metals like titanium require a very clean environment around the metal and specific types of tungsten electrodes, such as lanthanated or ceriated tungsten electrodes, and the use of a trailing shield to protect the metal from contact with the air. Aluminum metal require alternating current for its welding and the use of a rounded tip on the tungsten electrode to prevent the base metal from eroding the tungsten electrode rapid. You have to know how the base metal will react to the heat and the gas used in TIG welding to select the correct type of tungsten electrode.
Another common problem that can occur during the TIG welding process is tungsten electrode contamination. Tungsten electrode should not be allowed to touch the weld puddle during welding. If the tungsten electrode does touch the weld puddle, it will become contaminated.
If the tungsten electrode becomes contaminated during the welding process, the arc will wander and become unstable. Furthermore, there is nothing that you can do to fix the tungsten electrode once it becomes contaminated. You will have to cut the contaminated end of the tungsten electrode.
You also should not use a grinding wheel that is contaminated with metallic particle because the contamination will also be transferred into the tungsten electrode. Use a dedicated diamond grinding wheel to grind your tungsten electrodes to ensure that no metallic particles is ground into the tungsten electrode. To produce professional quality weld, there are specific steps that must be followed to properly set up your welding process.
First, you have to select the correct size of tungsten electrode based off the amount of amperage you will use during the welding process. Second, you have to prepare the tungsten electrode tip to the proper shape based on the metal you are welding. Third, pre-purge the argon gas in the welding system to remove the oxygen in the gas cup.
Removing the oxygen will prevent the formation of black oxidation on the weld and ensure that the weld is free from contamination. Finally, maintaining your tungsten electrodes in a case will allow you to have more better control over the TIG welding process.
