EFFECT OF ELECTRODE FORCE ON FRACTURE TYPE OF DQSK STEEL RESISTANCE SPOT WELDS

Abstract

Failure mode is a qualitative measure of resistance spot weld performance. To ensure reliability of resistance spot welds during vehicle lifetime, process parameters should be adjusted so that the pullout failure mode is guaranteed. In this paper, the effect of electrode force on the failure mode of drawing quality specially killed (DQSK) steel resistance spot welds during the quasistatic tensile-shear test is investigated. Results showed that there is a minimum weld nugget size to ensure pullout failure mode. It was found that increasing electrode force decreases fusion zone size and therefore leads to transition of failure mode from pullout to interfacial mode.