预弯曲变形对CP800复相钢力学性能的影响  

Effect of pre-bending deformation on mechanical properties of complex phase steel CP800

作　　者：孙昊飞 肖志 韦凯[2] 杨旭静[2] 齐军[3] SUN Hao-fei;XIAO Zhi;WEI Kai;YANG Xu-jing;QI Jun(State Key Laboratory of Vehicle NVH and Safety Technology,Chongqing 401122,China;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha 410082,China;Shanghai Huizhong Automobile Manufacturing Co.,Ltd.,Shanghai 201814,China)

机构地区：[1]汽车噪声振动和安全技术国家重点实验室,重庆401122 [2]湖南大学汽车车身先进设计及制造国家重点实验室,长沙410082 [3]上海汇众汽车制造有限公司,上海201814

出　　处：《材料工程》2021年第8期81-88,共8页Journal of Materials Engineering

基　　金：汽车噪声振动和安全技术国家重点实验室2019年度开放基金项目(NVHSKL-201901)。

摘　　要：对CP800复相钢进行冲压成型,制备预弯曲试样,并利用EBSD、X射线残余应力分析仪、拉伸试验机、DIC技术等研究预弯曲变形对钢的微观组织、残余应力和力学性能的影响。结果表明:预弯曲后残余应力分布情况呈现为拉-压-拉-压交替分布,即内表面(压缩层)呈现拉应力而外表面(拉伸层)呈现压应力,这种特殊分布情况会导致预弯曲后材料的屈服应力降低16%。同时,由于冷变形导致的材料硬化和位错强化效果,预弯曲后材料伸长率降低25%而抗拉强度增大24%。此外,预弯曲后内表面由于存在拉伸残余应力而导致更大的塑性应变和损伤,并早于外表面发生断裂。The pre-bending specimens were obtained by stamping with complex phase steel CP800,and the effect of pre-bending deformation on microstructure,residual stress and mechanical properties of the steel were studied by using EBSD,X-ray residual stress measurement system,tensile testing machine,DIC technique,etc.The results show that the distribution of residual stress of pre-bending specimens exhibits stress distribution of tension-compression-tension-compression,which means that the inside surface(compression layer)is tension stress and outside surface(tension layer)is compression stress.Such special distribution leads to a 16%reduction of yield stress of specimens after pre-bending.Meanwhile,due to the dislocation strengthening and hardening caused by cold deformation,the elongation of material decreases by 25%and the tensile strength increases by 24%after pre-bending.Furthermore,it is found that the inside surface produces greater plastic strain and is broken earlier than the outside surface due to the existence of tensile residual stress.

关 键 词：复相钢 预弯曲 残余应力 表面应变场 力学性能 

分 类 号：TG113.25[金属学及工艺—物理冶金]