NON CONSUMABLE ELECTRODES
There are various types of non-consumable electrodes on the market:
- pure tungsten electrodes. These are used with low current intensities and alternating current since the arc is more stable. In terms of cost, these are the cheapest electrodes.
- thorium-tungsten electrodes. These withstand high current intensities. The arc is easy to strike and, once struck, remains quite stable. These electrodes are recommended for welding steel with direct current and straight polarity.
- zirconium-tungsten electrodes. These are used for manual welding of aluminium, magnesium and its alloys, with a medium-low current intensity.
Before use the end of the electrode need to be ground on a silicon carbide wheel to give the most appropriate profile. Contamination with other metals must be avoided as this lowers the melting point of the electrode, for DC welding a sharp point is required and for AC welding only a small bevel is needed.