Preventing high short circuit currents when striking an arc - for the metal inert-gas welding of aluminium

摘要

In an arc striking process for welding with consumable electrode wire, esp. when the wire has a good thermal conductivity, the end of the wire projecting out of the electrical contact nozzle is prehated before the arc is struck, pref. to a temp. where the short circuit current generated in arc striking corresponds to the welding current. The preheat temp. is pref. 50 to 100% of the melting temp. of the wire and preheating may be carried out using an autogenous flame, induction heating, hot air, focussed electromagnetic beams, or a high voltage spark using an auxiliary arc.