Resistance Spot Welding between Steel and Aluminum Alloy

Aluminum alloy A6061 and mild steel Q235 sheets were welded by resistance spot welding. The interfacial microstructure was observed and the feature and distribution of the interfacial reactant were analyzed and the effects of welding current on the nugget size and tensile shear strength of the joint were investigated. The results indicate that both the tensile shear strength and nugget diameter of the joint increase with the increasing of welding current in some degree. When welding current exceeds a certain range, the nugget diameter of the joint tends towards stability and the tensile shear strength decreases. The joint with the maximum tensile shear load of 1.5 kN is obtained at the condition of 12 kA welding current. The interfacial reaction layer thickness decreased from central joints region to surrounding area.