Simulation of deep penetration welding of stainless steel using geometric constraints based on experimental information

Abstract

Results of a numerical simulation of deep penetration welding of 304 stainless steel are presented. This numerical model calculates the temperature and fluid velocity fields in a three-dimensional workpiece undergoing deep-penetration electron beam welding. The deposition of power from the beam and energy outflow at the model-system boundaries is effected by means of time-dependent boundary conditions on the equations of energy and momentum transfer. The vapor-liquid interface defining the keyhole is represented by a surface whose temperature is that of vaporization for the steel. On this surface, are specified boundary conditions for the momentum transfer equations such that the component of the velocity normal to the keyhole vapor-liquid interface is zero. In addition, this study introduces two new numerical procedures. These procedures are based on the inclusion of experimental information concerning beam spot size and weld pool geometry into the model system via constraints and the deduction of effective keyhole shape via an inverse mapping scheme.