Numerical Model of Rail Flash Welding Liquid Bridge Heating Process

The process involving liquid bridge heating and blasting influences the temperature field distribution of rail welded joints, safeguarding of high-temperature end metals, flatness of the end face pre-upsetting, and subsequent upsetting process. Despite the importance of these effects, there is a scarcity of comprehensive studies on liquid bridge heating. In order to address this gap, a two-dimensional axisymmetric simulation model was developed to examine the heating process of the liquid bridge. This model incorporates the coupling of the electromagnetic and thermal and flow fields was established. The blasting process parameters during the inherent vapor pressure were obtained through calculation. The simulation results showed that the droplets' flying speed, current density and blasting time were consistent with the results from the experiment. On this basis, the blasting process and evolution of the liquid bridge were analyzed. Analyzing variations in liquid bridge morphology, this study investigated the distribution of current density, electromagnetic force, Joule heat, temperature field, and velocity field. The findings offer valuable insights for optimizing and reducing defects in the rail flash welding process.