Multi-scale modeling of solidification and microstructure development in laser keyhole welding process for austenitic stainless steel

Amulti-scale model is developed in this paper to investigate the growth of grains and sub-grain dendrites during the molten pool solidification of austenitic stainless steel AISI304 in laser keyhole welding processes. A macro-scale dynamic model is used to predict the fluid flow and heat transfer in the keyhole as well as the molten pool. The generated thermal history is fed to a three-dimensional Cellular Automata model to predict the meso-scale grain growth and to a two-dimensional Cellular Automata-Phase Field model to predict the micro-scale dendrite morphology. The multi-scale model is applied to simulate multiple cases of different welding parameters. The model predictions are validated against experiments and studied further for detailed information. The effects of the welding parameters are discussed based on the numerical and experimental results. (C) 2014 Elsevier B.V. All rights reserved.