Numerical Simulation and Fatigue Properties of Laser Spot Weld-Bonding DP590 Dual-Phase Steel Joints

Abstract

In this paper, cold-rolled DP590 dual-phase steel sheets with 1.5 mm thickness were weld-bonded by a fiber laser. In order to study the tensile shear strength of laser spot-welding and laser weld-bonding joints, the orthogonal test was designed with three parameters: welding power, welding time and off-focus value. The tensile shear test and the fatigue test were carried out. The vaporization of the adhesive and its disruption to the molten pool during the weld-bonding process were simulated. The results show that the tensile and fatigue strength of the laser weld-bonding joints are higher than the laser spot-welding joints. Simulation results demonstrate that the perforation is caused by the gas produced by the gasified adhesive being discharged from the center of the molten pool under high pressure.