Characteristics of electrode wear in spot welding of hot galvanized dual-phase high strength steel

Hot galvanized dual-phase high strength steel is a new steel to be used in auto body to meet automobile light-weight and safety requirements. It has high strength and good corrosion resistance, but spot welding of this dual-phase steel has serious and uncertain electrode wear, which has great effect on weld quality. Firstly weld lobe of welding dual-phase steels with 600 MPa strength(DP600)was established by experiment, and then welding parameters according to the weld lobe were determined to carry out electrode wear experiment. Characteristics of electrode face morphology, radial and axial electrode wear were studied during the electrode wear test. Contribution ratios of electrode axis wear on radial wear at different wear stages were analyzed.The results showed that electrode wear rate was higher at beginning welds than later welds;pitting building at electrode surface accelerated electrode wear and invalidation.