Physical Simulation of Flash Butt Welding of 590CL Steel for Automotive Wheel Using: Process, Microstructure and Mechanical Properties

This study investigates the flash butt welding (FBW) process of 590CL steel, a high-strength low-alloy (HSLA) steel designed for automotive wheel rims. The research focuses on the microstructure and mechanical properties of the welded joints, with a particular emphasis on the heat-affected zones (HAZs) and the base material. The study employs physical simulation to reproduce the FBW process, allowing for a detailed analysis of key process parameters such as flash allowance, flash speed, and upsetting allowance. The findings reveal that increasing the flash allowance enhances the microhardness of the HAZs due to higher dislocation density and the potential formation of Widmanstätten ferrite. Conversely, higher flash speeds reduce the hardness of the HAZs by decreasing dislocation density and the nucleation of bainite and acicular ferrite. The study also shows that increasing the upsetting allowance reduces the microhardness of the coarse-grained HAZ by extruding hardened material, but a small increase in upsetting allowance can raise microhardness due to increased dislocation density. The ultimate tensile strength of the FBW-ed samples remains unaffected by the processing parameters, meeting industry standards. The ductility of the samples ranges from 16 to 18%, with plastic deformation and fracture occurring in the base material during tensile tests. This research provides valuable insights for optimizing the FBW process to improve the mechanical performance of 590CL steel in automotive wheel rim applications. The innovative use of physical simulation offers a novel pathway for FBW process optimization in advanced HSLA wheel rim steels.