淬火制度对Q&P钢微观组织和力学性能的影响  

Influence of quenching process on microstructure and mechanical properties of Q&P steel

作　　者：蒋爱娟 祝贞凤[1] 高千林 李辉[1] JIANG Ai-juan;ZHU Zhen-feng;GAO Qian-lin;LI Hui(College of Engineering,Yantai Nanshan University,Yantai 265713,Shandong,China)

机构地区：[1]烟台南山学院工学院

出　　处：《钢铁》2019年第10期80-84,共5页Iron and Steel

基　　金：山东省自然科学基金资助项目(ZR2018MEM007)

摘　　要：为了研究不同淬火制度对汽车用高强Q&P钢配分过程微观组织演变和力学性能的影响,利用激光共聚焦显微镜(LSCM)、环境扫描电子显微镜(SEM)和X射线衍射仪(XRD)表征了不同工艺状态后的微观组织,测试了力学性能,分析了加工硬化速率变化规律。试验结果表明,完全奥氏体化处理后立即进行Q&P处理,可以得到最高的屈服强度和抗拉强度,分别达到了1 185和1 315MPa,屈强比最高;奥氏体化后慢速冷却至两相区生成一定的铁素体,Q&P处理后得到最高的伸长率为28%和强塑积为29.5GPa·%。加工硬化速率的变化过程分为3个阶段,即屈服点前急剧降低的阶段Ⅰ,TRIP效应发生过程的缓慢降低阶段Ⅱ,快速下降直至材料断裂的阶段Ⅲ。Q&P热处理淬火配分前的初始微观组织状态,决定了淬火和配分过程的相演变和元素再分配过程。经工艺2处理后的残留奥氏体体积分数最高,达到12.2%,具有最高的伸长率和强塑积。In order to investigate the effect of quenching process on microstructure evolution and mechanical properties of Q&P steel for automotive,the microstructure was characterized by laser scanning confocal microscopy(LSCM),scanning electron microscope(SEM)and x-ray diffraction(XRD).The mechanical properties was tested and the work hardening rate was analyzed.The results indicate that Q&P treatment immediately after austenization process gets the highest yield strength and tension strength,which arrives 1 185 and 1 315 MPa respectively,and has highest yield ratio.The highest elongation(28%)and strength-ductility balance(29.5 GPa·%).The work hardening process has three stages,which are sharply decreased stageⅠ before yield point,slowdown stageⅡ based on TRIP effect and rapid reduction stageⅢ until fracture.The microstructure constitution before quench and partition decide the phase transition and element distribution.The highest volume fraction of retained austenite(12.2%)is reached after process 2 which has the highest elongation and strength-ductility balance.

关 键 词：初始组织 Q&P钢 力学性能 加工硬化 残留奥氏体 

分 类 号：TG1[金属学及工艺—金属学]