Simulation of Fixture Hardening for Tool and Process Design Optimization

Abstract Fixture hardening is the process of choice when thin-walled, carburized gears need to be heat treated with minimal distortion. Only a few publications have studied and described the phenomena taking place in carburized gears during a fixture hardening process. An integrated approach is proposed to improve the design of hardening fixtures and introduce new strategies and instrumentation to better understand and control the process. The proposed approach is to tightly integrate the knowledge in metallurgy, numerical simulation, process control, and machine design areas to mutually compensate and overcome the current limitations in each single area. An instrumented fixture is designed for a reference gear and tested on an industrial quenching press. The signals from the fixture are combined directly with the signals from the quenching press, recorded, and used to validate and improve the numerical simulation models. Metallurgical simulations are used to predict temperature distribution, phase transformations, distortion, and to identify new process strategies.