The Parameter Optimization of Dissimilar Resistance Spot Welding on Ultra-high Strength Hot-formed Steel and Mild Steel by Numerical Simulation

摘要

According to the design requirements of automotive lightweighting and crash safety, resistance spot welding (RWS) process on dissimilar steels is widely used on automotive body manufacturing. The weld qualities and mechanical properties after RSW process on the dissimilar steels significantly affect durability and crashworthiness of the vehicle [1]. Ultra-high strength hot-formed steel (UHSS) is a new kind of structural steel perfectly suit for automotive body. In this study, a coupled axisymmetric finite element model (FEM) was build to simulate the RSW process between UHSS and mild steel, by SORPAS software. Via simulating this process, the temperature distribution and dynamic temperature curves of welding area were studied, and welding spatter phenomena were predicted and validated by comparing them with experimental results. Via adjusting the welding parameters assist in numerical simulation, appropriate welding parameters were achieved. Moreover, the mechanic properties of the welding joints in optimized parameters were also compared with those of not optimized. The study results have already been applied in a manufacturing production. It can also provide guidance for the RSW on UHSS and mild steel.