【摘要】 依据相变动力学理论,对高强度钢板热成形微观组织转变与力学性能预测模型进行研究。基于该模型建立汽车前立柱下角撑的热成形有限元模型,采用热-力-相变耦合分析方法对热成形过程进行仿真分析,得到制件的温度、组织和硬度的分布及变化。以高强度硼钢USIBOR1500为试验材料对汽车前立柱下角撑进行试制,并从成形件上取样进行微观组织分析和力学性能测试。结果表明,成形件的微观组织为均匀板条状马氏体,抗拉强度达到1 400MPa以上,3个典型位置的硬度均大于450HV,且力学性能分布与模拟结果一致,验证了所建立模型的可靠性。更多还原

【Abstract】 According to the phase transformation kinetics theory,the model of microstructure transformation and mechanical properties prediction for high strength steel hot forming was analyzed.And based on this model,a hot forming FE model of automotive front pillar lower gussets was established,the hot forming process was simulated using thermal-mechanical-metallurgical coupling method,and the temperature,microstructure and hardness distribution and changes of the part were obtained.Then some trials of the automotive front pillar lower gussets were accomplished with high strength boron steel USIBOR1500as experiment material,and the microstructure and the mechanical properties of the samples on the formed parts were analyzed and tested.The experimental results show that the microstructure of the formed parts is uniform lath martensite,the tensile strength is greater than 1 400MPa,the hardness of three typical positions are above 450HV and the distribution of the mechanical properties agrees well with the numerical simulation results,which verify the reliability of the established model.更多还原