Method for resistance spot welding of zinc-coated high-strength steel

Abstract

This invention relates to the field of welding technology, specifically providing a resistance spot welding method for galvanized high-strength steel, aiming to solve the problem of easy formation of liquid metal brittle cracks in existing resistance welding methods for galvanized high-strength steel. To this end, the resistance spot welding method for galvanized high-strength steel of this invention includes the following steps: pre-welding the galvanized high-strength steel sheet using a single-pulse current, causing the galvanized layer in the contact area between the galvanized high-strength steel sheet and the welding electrode to melt into liquid zinc, and using the pressure applied to the galvanized high-strength steel sheet by the welding electrode to expel some of the liquid zinc from the contact area; performing the main welding of the galvanized high-strength steel sheet using a gradually increasing multi-pulse current, to reduce the temperature of the contact area between the galvanized high-strength steel sheet and the welding electrode through the cooling interval between the pulse currents of the gradually increasing multi-pulse current; the initial current value of the gradually increasing multi-pulse current is greater than the current value of the single-pulse current. This resistance welding method can effectively suppress the formation of zinc-induced liquid metal brittle cracks and improve welding stability.

Images