- The electrode materialTungsten
The tungsten not melting electrodes are applied in such type of welding as TIG - Tungsten Insert Gas (WIG, GTA, ADS) - manual, semi-automatic, automatic arc welding by not melting electrode in the environment of inert protective gas. The used gases: inert (argon or helium), active (carbon dioxide, nitrogen, oxygen, hydrogen) or their mixes (Ar + CO2, Ar + O2, Ar + Not).
Electrodes from a tungsten alloy with oxide of WL-20 lanthanum have very easy initial start of an arch, low tendency to prozhoga, Electrodes from a tungsten alloy with oxide of WL-20 lanthanum have very easy initial start of an arch, low tendency to prozhoga, a steady arch and the excellent characteristic of repeated ignition of an arch. Addition 1,5 - 2,0% of oxide of lanthanum increases the maximum current, the bearing ability of an electrode is about 50% more for this standard size when welding on alternating current, than purely tungsten. In comparison with ceric and thorium, lanthanum electrodes have smaller wear of the working end of an electrode. Lanthanum electrodes are more durable and pollute tungsten a welded seam less. Oxide of lanthanum is evenly distributed on electrode length that allows to keep a long time when welding initial sharpening of an electrode. This serious advantage when welding on constant (direct polarity) or alternating current from the improved sources of welding current staly and stainless steels. When welding on alternating sinusoidal current the working end of an electrode has to have spherical shape.