中文摘要：

在对冷轧相变诱发塑性钢TRIP780和烘烤硬化钢BH180两种钢板基本力学性能分析的基础上,通过U形件冲压成形试验分析这两种钢板的回弹对压边力和模具圆角半径变化的敏感性.对U形件冲压成形卸载后1 min至零件放置12周期间的回弹进行监测,重点对随时间变化的回弹即时效回弹进行详细的分析和讨论.采用X射线衍射对TRIP780钢中奥氏体体积分数随时效时间的变化趋势进行研究.结果表明,TRIP780钢不仅具有高强度、良好塑性和回弹大的特点,而且有显著的时效回弹,BH180基本没有时效回弹.TRIP780钢U形件卸载后l天内时效回弹最大,然后趋于稳定,卸载12周后时效回弹相对初始回弹的最大比例达到20％.X射线衍射结果表明时效回弹与相变诱发塑性效应有内在联系.TRIP780钢对压边力的变化更为敏感,可利用这个规律进行回弹控制.

英文摘要：

The mechanical properties of cold-rolled transformation-induced plasticity steel TRIP780 and bake hardening steel BH180 are compared.By U-shaped part stamping testing,sensitivity of blank holder force and punch radius on springback of the two steels are analyzed.Springback of the U-shaped parts occur during the time of one minute to 12 weeks after it is unloaded are measured.Emphasize is put on the analysis and discussion on the time-dependent springback which meant springback varied with time.X-ray refraction testing is performed to study the trend of retained austenites in TRIP780 steel.Results show that the investigated TRIP780 steel not only combined high strength,preferable ductility and large springback,but also it has prominent time-dependent springback,which is hardly found in BH180 steel.The amount of time-dependent springback of TRIP780 steel occurs in the first day after it is unloaded reaches the climate and then it tends to be stable.Twelve weeks after unloading,the max percentage of time-dependent springback to the initial springback could reach 20％.X-ray refraction indicates that there exists an inherent relationship between the time-dependent springback and the transformation-induced plasticity effect.TRIP780 steel is more sensitive to the blank holder force,which can be used in the springback control.