Numerical Simulation of Heat Treatment Based on the Model with Expanded Solution Domain

Jianfeng Gu, Jing Wang and Jiansheng Pan

Abstract: The heat treating of metals is a very complicated process in which multiple physical variables nonlinearly couple with each other. The heat transfer at gas–solid and liquid–solid interfaces is the most important problem to be solved in the numerical simulation of heat treatment, which is also the basis for the process design and equipment design of heat treatment. The traditional way in which one takes the parts as investigation objects and sets the heat transfer coefficient on the interface directly inevitably brings significant inaccuracy to simulation results. A series of research achievements in fluid mechanics and heat transfer theory have provided effective ways of dealing with this problem in heat treatment modeling. In this paper, a heat treatment model with an expanded solution domain is proposed after a brief summary of related research results for coupled heat transfer. In this model, the solution domain has been expanded to the surroundings of the heat treating parts. Taking the heating process in an industry furnace as an example, not only the parts and fixture but also the furnace body, furnace chamber, heating units, and all other components in the furnace are modeled as a whole. The virtual equipment design for a novel bell-type gas nitriding furnace has been successfully fulfilled based on the heat treatment simulation and demonstrates the giant advantage of this new model. It is necessary to emphasize that as an important step in the numerical simulation of heat treatment, this new model is far from mature, and a series of key problems still remain.