Expulsion Reduction in Resistance Spot Welding by Controlling of welding Current Waveform

Abstract

There is a welding problem such as expulsion in resistance spot welding of high strength steel. This is due to overheating induced by increase of total heat input. Recently, many studies are carried out to solve the problems using electrode force control and current control. In this study, we tried to achieve expulsion reduction through controlling welding current. Steel sheet coated by Al-Si that has strength of 1500 MPa was selected as a base material. The control results were compared with conventional welding method. Also, it is characterized how the variation of the heating and cooling by pulse current waveform control have an effect on expulsion.