Welding time effect of welding joints in micro alloyed and TRIP 800 steels in resistance spot welding

Abstract

This paper presents an analysis of resistance spot welds between micro alloyed steel sheets having 1 mm thickness and TRIP 800 (transformation-induced plasticity) steel sheets having 1.5 mm. TRIP 800 steel and micro alloyed steel sheets are used in automobile chassis and automobile body parts, respectively. In this study, resistance spot-welding method was used for joining steel pairs to be lap joint. A time and current controlled resistance spot welding machine having 120 kVA capacity, and pneumatic application mechanism were used in the experiments. Specimens prepared for spot welding operations were joined with different welding time ranging from 5 to 30 periods (1 period = 0.02 s) and different weld currents, ranging from 8.5 to 16.5 kA in 0.5 kA steps. The electrode force was kept constant at 6 kN. Tensile-peel tests were applied to the welded specimens. The effect of welding time parameter on tensile-peel properties was analyzed. The highest tensile-peel load was obtained using 15 periods.