Effects of phase changes on weld pool shape in laser welding

A mathematical model is developed to relate the weld depth and width to the laser parameters. The model is based on the Stefan condition for quasi-steady state laser welding. Simple expressions are obtained for the shapes of the solid-liquid and liquid-vapour interfaces. They are found as functions of the laser irradiance, welding speed, absorptivity and thermal diffusivity. Simple expressions for the temperature distributions in the liquid and solid phases are also presented. The results for the weld depths and widths and the temperature distributions in the workpiece are illustrated for various laser intensities and welding speeds. The predictions of this simple model are found to compare well with experimental data and other previous models