FE-Based Analysis of Hot Forming Process Using the Flow Stress Prediction Model

In hot forming process, the workpiece undergoes plastic deformation at high temperature and the microstructure of the workpiece changes according to the plastic deformation. These changes affect the mechanical properties of workpiece. In order to optimize this process, both the plastic deformation of workpiece and its microstructural changes should be taken into consideration. Since material behaviors at elevated temperatures are usually rate-sensitive, the analysis of the hot forming processes requires a thermo-viscoplastic model. In this paper, by coupling the flow stress prediction model developed with finite element analysis of thermo-viscoplastic of the hot upsetting process, temperature, strain rate, flow stress distributions and geometry of the workpiece at each time step can be calculated. At each time step, the strain rate and temperature at each element are obtained. From these values and the history of deformation, the changes in microstructure and flow stress can be determined. Keywords: Hot forming, Process, Finite element analysis, Flow stress, Microstructure, Hot upsetting process