Modelling and simulation of equilibrium and non-equilibrium solidification in laser spot welding

Abstract

In this work, rapid solidification in laser welding is studied by solving transient, coupled, governing equations of mass, momentum and energy conservation using a fixed-grid, finite volume methodology. The solidification process in laser welding occurs with high cooling rates involving rapid solidification kinetics. The non-equilibrium phase change is accounted at the solid-liquid interface of the weld pool and it is assumed that heterogeneous nucleation occurs instantaneously when the temperature in the melt pool reaches the nucleation temperature. Simulation results of laser welding with undercooling and without undercooling are compared. It is found that the melt pool width is larger in the case of undercooling case, however, the maximum temperature in the weld pool is higher in the case of without undercooling case.