Influence of electrode force on weld expulsion in resistance spot welding of dual phase steel with initial gap using simulation and experimental method

Abstract

By increasing the electrode force, it would be an alternative way to avoid weld expulsion in resistance spot welding (RSW) of dual phase (DP) steel with initial gap. To investigate the influence of the electrode force on weld expulsion, a weld expulsion estimation method based on a finite element model were used to analyze the contact state, electrical field, temperature distribution and weld nugget formation process. The simulation results were validated by the experiments. It was shown that a great electrode force could be helpful to inhibit weld expulsion by improve the contact state between sheets. For 0.8 mm DP600 steel with 1.6 mm gap spacing, the minimum electrode force without expulsion is about 2.5 kN. For DP600 steels with different thickness from 0.8 to 1.8 mm, minimum electrode forces have been determined to inhibit the weld expulsion with different gap spacing to improve the weld quality of RSW. © 2012 ISIJ.