Simulation of Integrated Heat‐treatment of Precision Forged Components

Abstract

Precision forging with integrated heat-treatment (cooling from the forging temperature by means of spray cooling) is an innovative process for manufacturing high performance components such as surface hardened and tempered gear wheels. Using a process chain which is shortened in comparison with conventional process sequences, production times can be lowered and processing energy can be saved. With respect to the work piece, a numerical computation of the process steps from precision forging, quenching and tempering from the residual heat can be performed to support the process design. Here, the aims are to predict suitable process parameters and mechanical properties of final components. In the following, the modelling approach exemplified using of a gear wheel of hardening and tempering steel 42CrMo4 is to be introduced which is employed for the collaborative research centre 489 “Process chain for manufacturing precision forged high performance components” at the Leibniz Universitat Hannover. Microstructure developments, as e.g. recrystallisation, grain growth and microstructural transformations, as well as mechanical properties due to tempering by the residual heat are considered for this process using the commercial finite element software ANSYS®. For this purpose user specified sub routines were developed to enhance the capabilities of ANSYS® by the application of the Ansys Parametric Design Language (APDL) and User Programmable Features (UPF), respectively. Results of the computation can be verified by micrographs and hardness measurements.