高强塑积汽车钢板的显微组织与力学性能  

Microstructure and mechanical properties of automobile steel sheet with high strength-ductility balance

作　　者：张丽凤[1] 王社则 田博彤 ZHANG Li-feng;WANG She-ze;TIAN Bo-tong(Department of Vehicle Engineering,Shanxi Traffic Vocational and Technical College,Taiyuan 030031,China;School of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]山西交通职业技术学院车辆工程系,山西太原030031 [2]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《塑性工程学报》2021年第11期181-188,共8页Journal of Plasticity Engineering

基　　金：国家重点研发计划项目(2016YFB0301001-3);山西省重点研发计划项目(2017KKJH)。

摘　　要：采用扫描电镜、透射电镜和拉伸试验机等手段研究了Nb和C含量对传统淬火-回火(Q-T)态和新型淬火-分配-回火(Q-P-T)态汽车钢板拉伸性能和显微组织的影响。结果表明,Q-T态试样中未见明显奥氏体衍射峰存在,而Q-P-T态试样中可见衍射峰强度不等的奥氏体衍射峰;含Nb钢板的组织为回火马氏体+残余奥氏体+碳化物,且Q-P-T态钢板中残余奥氏体含量相对较多;Nb元素的添加有助于提高Q-P-T和Q-T态汽车钢板的强度,而对塑性影响较小,适宜的Nb添加量为0.03%;Q-P-T工艺有助于同时提高含0.4%C+0.03%Nb汽车钢板的强度和塑性,此时汽车钢板具有最高的强塑积(32008 MPa·%),这主要与钢板中含有起协调变形能力的薄膜状残余奥氏体以及起第二相强化作用的含Nb碳化物有关。The effects of Nb and C contents on the tensile properties and microstructures of traditional quenched-tempered(Q-T)state and new quenched-distributed-tempered(Q-P-T)state automobile steel sheets were studied by means of scanning electron microscopy,transmission electron microscopy and tensile testing machine.The results show that there is no obvious austenite diffraction peak in Q-T state specimens,however,there are austenite diffraction peaks with different intensity in Q-P-T state specimens.The microstructure of Nb-containing steel sheet is tempered martensite+retained austenite+carbide,and the content of retained austenite in Q-P-T state steel sheet is relative more.The addition of Nb element can improve the strength of Q-P-T state and Q-T state automobile steel plate,but has little effect on plasticity,the suitable addition amount of Nb is 0.03%.The Q-P-T process can improve the strength and plasticity of0.4%C+0.03%Nb automobile steel sheet at the same time,and the automobile steel sheet has the highest strength-ductility balance(32008 MPa·%),which is mainly related to the film-shaped retained austenite with compatible deformation ability and Nb-containing carbides with action of second-phase reinforcement in the steel sheet.

关 键 词：淬火-配分-回火 残余奥氏体 强塑积 

分 类 号：TG161[金属学及工艺—热处理] TG142.1[金属学及工艺—金属学]