Exponential Model of Strength-Hardness Mechanical Properties Analysis and Numerical Prediction in Hot Stamping

Hot stamping is an advanced sheet forming technology integrating traditional forming and quenching technique for high strength and hardness simultaneously in the process. This paper has investigated the mechanical properties evolution history of hot stamping boron steel 22MnB5 with different cooling rates under non-isothermal quenching process. It has been conducted for analyzing the effect of divided stage cooling influences on the mechanical properties of 22MnB5 by the martensite transformation temperature point Ms. A series of tests were conducted using the divided stage cooling tool in order to acquire the cooling rates hardness, mechanical strength of different quenching process. The hardness-cooling rate exponential model and mechanical strength-hardness-cooling rate exponential model were established by using the dimensional analysis method and the inverse method based on numerical analysis software MATLAB. The model has been applied to the prediction simulation in the self-developed software KMAS_HF to validate the hardness and strength prediction in hot stamping. The typical U-shape hot stamping experiment was investigated for the numerical simulation of non-isothermal quenching process. The evaluation result shows that the model has a good reliability and applicability for predicting the hot stamping mechanical properties, which can be used to guide the optimization of hot stamping process and the design of hot stamping tools.