Numerical simulation of asymmetric fillet weld pool based on temperature field and flow field coupling

The temperature field and flow field were analyzed to solve the problems of unstable penetration and poor forming quality, which always happen in asymmetric fillet welding. In order to explore the effect of the welding parameters on welding and improve the quality of forming, a three-dimensional mathematical model of asymmetric fillet welding was established by using the finite element software COMSOL and the coupling equation. The model was considered about the surface tension gradient, the electromagnetic force, gravity and the effect of temperature, radiation and convection heat on physical properties of the material. The flow field and the growth pattern of the weld pool were analyzed, and the weld pool geometry under different welding currents was compared. The results show that, the thin metal was preferentially penetrated, and with the welding process the weld width expanded until the weld beam was full-penetration. The heat affected zone was got from weld experiments, its shape and size agreed well with the simulation results, which verifies the validity of the theoretical analysis.