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. Common rare earth additives include cerium oxide, lanthanum oxide, zirconium oxide, yttrium oxide, and thorium oxide.
Scope of application
The tungsten electrode is used for TIG welding. This is a tungsten alloy bar made by mixing 0.3%-5% rare earth elements such as cerium, thorium, lanthanum, zirconium, yttrium, etc. into 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 grounding 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.
Tungsten electrodes play an important role in arc starting, arc stability and welding quality in argon tungsten arc welding. The quality loss of the tungsten electrode under the action of the high temperature of the arc is called ablation of the tungsten electrode. In order to facilitate the discussion of the ablation mechanism of tungsten electrodes, ablation can be divided into ablation by adding oxide and ablation by tungsten itself.