Welding thin oxidised material using micro-plasma arc - welding only occurs in positive half-waves of rectangular alternating current

摘要

Process is for arc-welding thin parts, esp. oxidised parts using a plasma-arc between a non-consumable electrode and the parts being welded, the power supply having an alternating rectangular shape. During the first half-wave with the workpiece connected to the negative pole the power is somewhat below that producing a weld and only in the second half-wave, when the workpiece is connected to the positive pole, is sufficient power supplied to produce a weld. The power ratio in the two half waves, i.e. first: second, is pref. min. 1:3, esp. 1:5 and trigger is pref. used to supply each first half-wave; the frequency of the rectangular wave A. C. is pref. 5 Hz to 2 KHz with Ar as both the plasma and inert gas. Used for welding thin Al, e.g. 0.5-0.7 mm or other material, e.g. steel sheet V2A.