硼钢板与模具间接触热阻实验研究及其在回弹仿真中的应用

接触热阻是影响热冲压过程中热能传导的一个重要因素,而零件不同区域的温差则直接影响热冲压的回弹,因此,获得准确的接触热阻数值对提高热冲压回弹仿真的精度具有重要意义。基于稳态法设计了22MnB5板件与Cr7V模具钢接触热阻的测量实验,推导出接触热阻的计算公式;并按照实验方法搭建了实验平台,获得了不同压强下两者的接触热阻值;最后拟合了接触热阻与压强的关系方程。将关系方程带入某B柱的热冲压回弹仿真中,与原始仿真对比发现,改进后的仿真结果与实际实验值较为接近,证明获得准确的接触热阻与压强的关系方程可提高硼钢板热冲压回弹的仿真精度。

Experimental investigation on contact thermal resistance between boron steel and die and its application to springback simulation

The contact thermal resistance is an important influence of thermal propagation in the hot stamping process.However, the temperature difference among various regions of parts affects the hot stamping springback directly.So it is of great significance to obtain accurate contact thermal resistance for improving springback simulation accuracy in the hot stamping process.The measurement experiment on contact thermal resistance between boron sheet 22MnB5 and die steel Cr7V was designed by the steady-state method, and the calculation formula of contact thermal resistance was deduced.According to this measurement method, a test platform was built, and values of contact thermal resistance under different pressures were obtained respectively.Finally, a relational equation between contact thermal resistance and pressure was fitted.Furthermore, the relational equation was input into a B-pillar hot stamping springback simulation, and the improved simulation results were closer to the experimental one by comparing with the original simulation results.Thus, it is indicated that obtaining accurate relational equation between contact thermal resistance and pressure can improve simulation accuracy of springback in the hot stamping for boron steel.