汽车B柱热成形试验与热力耦合仿真

The hot forming experiment and thermal-mechanical coupled simulation of B-pillar for vehicle

热成形技术作为改善高强度钢板成形性及提高机械性能的先进制造技术,可在保证汽车被动安全性的前提下实现车身轻量化,具有重要的工业应用价值。本文基于典型汽车B柱热成形产品建立热力耦合有限元模型,对B柱热成形及淬火过程进行了数值模拟分析并与试验结果进行对比,从成形零件厚度分布、温度场及微观组织性能方面对其进行研究。结果表明:B柱产品中部拐角处厚度增加较大,尾部两侧成形壁厚减薄趋势较大,但都满足成形性要求;B柱降温速率大于27℃/s,可保证马氏体转变;成形后B柱的硬度可达450HV以上,抗拉强度可达1600MPa,微观组织为均匀的马氏体。成形后B柱各项性能均满足热成形技术规范要求。

The thermal-mechanical coupled model tor hot forming parts of typical vehicle B-pillar has been estahlished in the text. The hot forming and quenching process of B-pillar have been numerically simulated and the resuhs of simulation have been compared with experiment results. The thickness distribution, temperature field, and the microstructure functions of forming parts have been studied. The results show that both of the thickness at the central corner and the thickness thinning of two side walls are larger which can assure the formability. When the cooling rate of B pillar is more than 27℃/s, the martensite transformation has been ensured. The hardness of formed B pillar can be more than 450HV and the tensile strength can be more than 1600MPa. The microstructure is uniform martensite. The final properties of formed B-pillar satisfy the requirements of hot forming quality specification.