热冲压关键工艺参数对零件力学性能影响研究

摘要

成形温度是热冲压工艺的一个关键参数,直接影响热冲压零件的力学性能.本文基于热-力耦合弹塑性有限元模型进行了U形热冲压实验,分析了热冲压板料的冷却速率、温度分布,获得了成形温度对热冲压件微观组织、机械性能的影响.结合不同成形温度下的热冲压车门防撞梁准静态弯曲实验和动态冲击仿真,考察了成形温度对热冲压车门防撞梁承载能力的影响.结果表明:成形温度为600℃ ～700℃时可以实现热冲压板料的均匀淬火,其微观组织转变为条状马氏体,抗拉强度超过1400MPa;成形温度为650℃的热中压车门防撞梁兼具高强度和良好的塑性变形吸能能力,综合性能最优,适合用作车身防撞零部件抵抗碰撞变形.%The U-shaped hot stamping test has been carried out based on thermo-mechanical coupted plastic finite element model in the text.The cooling velocity and temperature distribution of hot stamping part have been analyzed.The influence of forming temperature to microstructure features and mechanical properties of hot stamping parts has been obtained.Based on static bending test and dynamic impact simulation of hot stamping door beams under different forming temperatures,the influence of forming temperature to capacity of door beams has been put forward.The results show that the uniform quenching of hot stamping parts can be realized during 600℃～700℃ forming temperature,the microstructure of which transforms into strip martensite and tensile strength is more than 1400MPa.The door beam formed at 650℃ has both high strength and good energy absorption ability,with comprehensive optimal performance,which can be used as a door beam to resist side impact deformation.