Pure Tungsten Electrodes
Because the melting point of the tungsten is very high, it is used to produce Tungsten inert gas (TIG) electrodes. Tungsten electrode is manufactured by the materials with high melting point, corrosion resistance, high density, good thermal and electrical conductivity. Tungsten electrodes can be made by pure tungsten and also can be made by tungsten alloys. Pure tungsten electrodes are made by pure tungsten above purity 99.5%. Tungsten alloys electrodes are made by tungsten with other element and oxides. Ceriated tungsten electrode and lanthanated tungsten electrode are the most common tungsten alloys electrodes. The addition of rare earth oxides to tungsten reduces its escape energy, thus improving its electron emission capability and improving its welding performance: better arc initiation performance, higher stability of arc column and lower burn rate of electrode. Different types and sizes of electrodes are used for different types of welding and different types of materials. Some electrodes work better with alternating current (AC) than with direct current (DC). So different electrodes are used for different purposes.
The pure tungsten electrode contains at least 99.5% tungsten. There are no alloying elements in it. Pure tungsten electrode has superior performance: steam pressure, low resistance, good conductivity, small thermal expansion, high elastic modulus. It is generally used for welding aluminum, magnesium alloys under the AC condition.