Combined CFD and Heat Treatment Simulation of High-Pressure Gas Quenching Process

Abstract To improve the process development for high pressure gas quenching a digital quenching simulation model combining the fields of computational fluid dynamics and heat treatment process simulation has been developed. It was found that the gas flow and hence the quenching properties depend on both local (geometry of parts, carrier and chamber) as well as global influencing factors (fan characteristics, system pressure and hydraulic resistances). Therefore, a computational fluid dynamics model that includes all these factors was realized. The approach includes a heat transfer analysis to determine the local heat exchange coefficients on a component level. By connecting the computational fluid dynamics model and heat treatment simulation the local quenching characteristics are used to compute the temperature history of the quenched part. Based on a thermo-metallurgical heat treatment simulation the computed local cooling curves and metallurgical phase compositions are used to accurately predict the part properties like microstructure and hardness. The applicability of the model has been confirmed by hardness measurements. Hardness results for different batch positions, batch setups or tray systems can now be computed enabling an efficient virtual development of the gas quenching process.