Optimization of Pinion Shaft Straightening Process by Incorporating Heat Treatment Information Extracted from Distortion Measurement

The straightness of carburized pinion gear shafts is strongly connected to the heat treatment process. While CAE analysis can be an effective tool to simulate the straightening process, the residual stress state in the part resulting from the heat treatment process is unknown. Furthermore, assuming uniform case depth and homogeneous material properties during simulation is unreasonable. To accurately simulate the straightening process, information about the heat treatment process must be obtained first. The objective of this paper is to develop a CAE process to extract the heat treatment process parameters from distortion measurements using the inverse method. Since distortion is a known result of heat treatment, it can be hypothesized that a one-to-one mapping exists from the thermal profile to the distortion pattern, assuming the quenching heat transfer coefficient is solely a function of surface temperature. Based on this assumption and by utilizing the inverse heat conduction method, the thermal profile of the quenching process can be obtained from the distortion measurements. Once the thermal profile is obtained, the case depth and material property distribution will also be known, enabling CAE analysis to model the straightening process..