Written by Miles Budimir
Senior Editor, WTWH Media
Electrodes are used in all-electric arc welding processes. In each of these processes, the electrode is used to create the electric arc between the electrode and the metals to be welded together, generating the heat with which to melt the base metals.
The electrodes used in arc welding can generally be categorized as consumable or non-consumable. Consumable electrodes become part of the weld bond itself. The electrode serves as the filler metal and melts along with the metals to be welded together.
For example, in typical electric arc welding, the consumable electrode is the filler metal welding rod and contains a flux that contributes to producing a barrier to protect the weld from any contamination. In contrast, non-consumable electrodes are not consumed during welding, with a separate welding rod serving as the filler metal that melts and joins the metals together.
For instance, non-consumable electrodes are used in TIG welding. Here, the electrode is made of tungsten, which has a high melting point of about 6,000˚ F, so it isn’t consumed during welding.
Consumable electrodes have extra considerations compared with non-consumable electrodes. As they’re consumed during the welding process and serve as material for the weld bead, the selection of electrode material is critical. This is because the electrode material must be compatible with the metals that are being welded together; that is, they must be chemically compatible.
Some of the most common materials for consumable electrodes include different types of steel, such as low alloy or nickel steel. They can be further distinguished by the type and amount of coating or flux on the electrodes, ranging from no flux coating at all to heavily coated types.
On the other hand, because non-consumable electrodes aren’t consumed during welding but remain intact, there’s no issue about the type of electrode material. Common electrode materials include carbon or graphite in addition to either pure tungsten or tungsten alloys.