THE WELDING ARC
The heat that is developed at the cathode and anode of an arc discharge is able to melt most of the metals and alloys. Hence, the arc is used as an intense heat source for joining of metals. For welding applications the arc may be struck between a non consumable electrode and a metal that has to be welded. (Example TIG welding & Plasma welding).
The arc can also be struck between a consumable electrode and base plate, (Flux & gas shielded welding processes). In atomic hydrogen welding the arc is struck between two tungsten (non consumable) electrodes and the flame of the arc is directed towards the metal to be welded. The welding arc can operate at a current as low as 1 A and less in the case of micro plasma welding and it can also operate at currents of the order of 1500 A in the case of submerged arc welding.