车门防撞梁热成形工艺优化仿真与试验

基于DYNAFORM软件热冲压模块，研究了由B1500HS钢制成的某型轿车车门防撞梁热成形过程。通过引入H13模具钢热物性参数，并将相变潜热因素考虑在内，利用多步差分法得到了温度场单元体变分公式；依据车门防撞梁结构特征进行工艺分析，建立了车门防撞梁的两种热力相耦合模型。通过对比分析两种方案下整体及典型M形截面应力场、温度场和厚度分布结果发现：带压料板式方案所得产品热成形及淬火后应力场、温度场及厚度分布均匀，更适合热冲压成形。最后依据压料板式方案进行了成形试制，得到车门防撞梁的显微组织均为马氏体，底部与顶部的马氏体板条更为细小，维氏硬度超过450HV，符合热冲压零件性能标准。

Simulation and Tests on Hot Forming Process Optimization for Door Anti-collision Beams

Based on the hot stamping module of DYNAFORM software, the hot forming process of one vehicle door anti-collision beam made of B1500HS steel was studied. By introducing the thermal physical parameters of H13 die steel, the variation formula of temperature field element was obtained by the method of multi-step difference, taking the latent heat of phase transformation into account. The structural characteristics of the door anti-collision beams were analyzed, two kinds of thermal-mechanical-metallurgical coupling models were established. After comparing and analyzing the stress fields, temperature fields and thickness distributions of the overall and typical M-shaped-section of the schemes, it is found that the scheme with pad is more suitable for hot stamping, because of their uniform distribution after hot forming and quenching. Finally, the hot stamping experiments were carried out, referring to relevant parameters of the scheme with pad, and the experimental results show that microstructures of the door anti-collision beam are all martensite. In addition, the martensites lath at the bottom and top is finer, and the Vickers hardness reaches above 450HV, which meets the performance standard of hot stamping parts.