Numerical simulation of keyhole behaviors and fluid dynamics in laser-gas metal arc hybrid welding of ferrite stainless steel plates

摘要

The fluid dynamics in weld pool and keyhole behaviors in laser-gas metal arc hybrid welding play a dominant role in affecting the weld quality of ferrite stainless steel plates. In this study, a transient model is developed for numerical simulation of the keyhole dynamics and heat transfer & fluid flow in hybrid weld pool. The heat, mass and momentum transfer due to droplets as well as the interaction between laser and arc are taken into account. The formation, expansion and sustainment of keyhole in weld pool are numerically simulated, and the transient variation of keyhole is demonstrated in three stages. The weld pool and keyhole shapes and sizes, and the fluid flow and thermal field in hybrid weld pool are quantitatively analyzed. The model is validated by hybrid welding experiments on ferrite stainless steel plates. It lays foundation for optimizing the process parameters in hybrid welding. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.