Braze-welding for dissimilar metals between copper and steel by Nd:YAG laser-plused MIG hybrid welding

Braze-welded joint between copper and steel could be achieved by laser-arc hybrid welding.With this method, high quality joining between T2 copper alloy sheet and galvanized steel sheet was successfully done.The results indicated that a brazed joint between copper and steel was formed, while the steel sheet in the joint was not melted.The tensile test shows that the crack initiated in the heat-affected zone of copper side, and the heat-affected zone is intenerated appreciably.Analy sis of fracture appearance shows that the fracture characteristic of the joint is ductile fracture.The erodent structure of the steel and the penetration of copper atom through the crystal boundary of ferrite were not found by hish resolution electron micnoscope.Copper-iron solid solution formed around the brazing interfaces and both atoms diffused with each other.In addition, the brazing interface abounded with silicon.