Flash butt welding process and microstructure controlling of 380CL wheel steel with micro Ti treatment

In order to solve the problem of high micro-cracking rate and bursting rate after rim flash butt welding (FBW), the 380CL wheel steel with thickness of 6.75 mm is taken as the research object. By studying the influence of the unified flash butt welding parameters on the joint hardness, the control mechanism of the flash butt welding temperature field is established in this paper. The hardening tendency of the 380CL after FBW is further reduced by the Ti microalloying technology. It’s shown that in order to ensure the well-done production rate after flash butt welding of 380CL, it is necessary to adopt a welding specification with a large temperature gradient and a reasonable forging amount to obtain an optimal welded joint. Under the FBW parameters of the burnt amount of 19 mm, the jaw distance of 36 mm, the burning rate of 1.2 mm/s, the point upset forging time of 0.5 s, and the upset forging of 7 mm, the 380CL wheel steel with thickness of 6.75 mm can obtain the lowest hardness value of 140HV2. The welding heat simulation of the micro-Ti treated 380CL wheel steel was carried out. The deformation resistance of the upset forging at 1 000 °C or higher was reduced, and the grain refinement of the microstructure was remarkably reduced, which significantly reduced the micro-cracking rate and the burst rate after FBW of 380CL. The researches above have been further promoted and applied demonstration of FBW to high-strength rim steel.