The influence of fluid phenomena on the laser beam welding process

A mathematical model for the simulation of characteristic weld pool phenomena during deep penetration laser beam welding based on a numerical solution of the conservation equations of energy, momentum and mass is presented. The modelling is carried out in dimensionless form and the various melt pool effects are investigated separately with regard to dependence on characteristic dimensionless groups. The developed three-dimensional simulation model allows numerical experiments in order to investigate the influence of the fluid dynamics in the fusion zone on the local temperature distribution. To assess the accuracy of the predicted weld pool shapes and sizes, the computed and experimentally determined seam widths of laser beam welded joints are compared for welds on different steels