Microstructure and Mechanical Properties of A6061/GA980 Resistance Spot Weld

Abstract

Resistance spot welding was performed on steel and an Al alloy to investigate the microstructural and mechanical properties of the joint. An Al-Mg-Si aluminum alloy A6061 and an alloyed zinc-plated steel sheet GA980 were used as specimens. Resistance spot welding was performed at welding currents of 16 kA, 20 kA, and 22 kA, welding time of 0.24 s, and welding pressure of 5 kN. To investigate the strength of the welds, the tensile shear test and the cross tension test were conducted, and the fatigue test was also conducted. The nugget diameter increased with an increase in the welding current. The tensile shear strength and cross tension strength increased with the increase in the welding current. In the tensile shear fatigue test, interface fracture was observed in the low cycle fatigue region. In the cross tension fatigue test, it was confirmed that the higher the welding current, the better the fatigue properties in the low-cycle fatigue region.