Orthogonal Optimization of Resistance Spot Welding Parameters and Microstructure and Mechanical Property of Aluminum Alloy/High Strength Steel Joint

Resistance spot welding with process tape was used to weld 5083 aluminum alloy and DP980 high strength steel. The effects of welding parameters on the microstructure and properties of the joints were studied. Orthogonal experiment method was used to obtain the optimal welding parameters. The results showed that welding parameters had great effects on the nugget diameter, intermetallic (IMCs) layer thickness and joint tensile shear force. The optimized parameters were 15 kA, 300 ms and 3.5 kN, and the most influential factors were welding current, welding time and electrode force in turn. The average nugget diameter and tensile shear force of the optimized joints reached 10 mm and 5.15 kN, respectively. The microstructure analysis and fracture behavior of the optimized joint were also conducted. The sufficient nugget diameter and continuous IMCs layer at the welding interface were main factors to ensure the high performance of the joint.