What is Tungsten Electrode?

Q: What is tungsten electrode?
A: Due to the characteristics of tungsten, it is very suitable for TIG welding and other similar electrode materials. Adding rare earth oxides to metal tungsten to stimulate its electronic work function, so that the welding performance of tungsten electrodes can be improved: the arc starting performance of the electrode is better, the stability of the arc column is higher, and the electrode burn rate is smaller.
Tungsten electrode is used for TIG welding. This is a tungsten alloy bar made by mixing 0.3%-5% of rare earth elements such as cerium, thorium, lanthanum, zirconium, yttrium, etc. in the tungsten matrix through powder metallurgy. The diameter is from 0.25 to 6.4mm, and the standard length is from 75 to 600. The most commonly used specifications are diameters of 1.0, 1.6, 2.4 and 3.2. The shape of the electrode tip is an important factor for TIG. When using DCSP, the electrode end needs to be ground into a sharp shape, and its tip angle varies with the application range, electrode diameter, and welding current. Narrow joints require a smaller tip angle. When welding very thin materials, A low current, needle-like smallest electrode is used to stabilize the arc, and a proper ground electrode can ensure easy arc ignition, good arc stability and proper bead width. When welding with AC power supply, there is no need to grind the electrode end, because when the proper welding current is used, the electrode end will form a hemispherical shape. If the welding current is increased, the electrode end will become bulb-shaped and may melt and contaminate the molten gold.
With the development and expansion of applications of inert gas shielded welding with tungsten electrodes, the research on tungsten electrodes has become more and more in-depth. In plasma arc welding, cutting and non-melting argon arc welding, thorium tungsten electrodes were used in the past, but due to the radioactive effect of thorium (the radiation dose is 3.60×105 Curie/kg), it will harm human health and pollute the environment Therefore, a cerium tungsten electrode with a cerium oxide content of 2 to 4% is used instead of a thorium tungsten electrode. In direct current argon arc welding, the cerium tungsten electrode is easy to start the arc, and the electrode burns less, and the welding current density is allowed to be higher than that of thorium tungsten; while in AC argon arc welding, the burn loss of the cerium tungsten electrode is larger than that of the thorium tungsten electrode. , The allowable range of welding current selected for the cerium tungsten electrode is smaller than that of the thorium tungsten electrode.
Thorium tungsten electrodes are easy to operate and work well even under overload currents. There are still many people using this material, and it is regarded as part of high-quality welding. Even so, people are gradually turning their attention to other types of tungsten electrodes, such as cerium tungsten and lanthanum tungsten. Because the thorium oxide in the tungsten thorium electrode produces a small amount of radiation, some welders are reluctant to approach them.