High-speed welding of zinc-coated steel sheets with double electrode GMAW

When zinc-coated steel sheets are welded by MIG welding with high current,the zinc coating is very easy to burn out under the high temperature.So it is hard to be welded by MIG welding in high speed.In order to solve this problem,bypass coupling welding arc bypass coupling welding arc GMAW had been used which is a kind of high efficiency and low heat input MIG welding.The system of DE-GMAW had been built up.And high-speed welding method for surfacing joint and lap joint of zinc-coated steel sheets with bypass coupling welding arc GMAW had been analyzed.The results showed that through adjusting the current of bypass,the heat input had lowered down with bypass coupling welding arc GMAW and was able to do the surfacing and lap welding with high current and speed.There was steady and no spatter in welding process.The weld formation was good and the base metal deformation was small.Meanwhile,the burning of zinc coating of bypass coupling welding arc GMAW was lower than MIG welding with same current.This will ensure the corrosion resistance of zinc-coated steel sheets.