不同热处理工艺对冷轧复相钢组织性能影响的研究  

Study on the effect of different heat treatment processes on microstructure and properties of a cold rolled complex-phase steel

作　　者：蒋睿婷 胡智评 林春青 郭金宇 徐鑫 黄镇宇 JIANG Ruiting;HU Zhiping;LIN Chunqing;GUO Jinyu;XU Xin;HUANG Zhenyu(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan 114009,China;AnSteel Iron and Steel Research Institute,Anshan 114009,China;Cold Rolled Strip Steel Mill,Angang Steel Co.,Ltd.,Anshan 114021,China)

机构地区：[1]海洋装备用金属材料及其应用国家重点实验室,辽宁鞍山114009 [2]鞍钢集团钢铁研究院,辽宁鞍山114009 [3]鞍钢股份冷轧厂,辽宁鞍山114021

出　　处：《轧钢》2024年第3期48-52,共5页Steel Rolling

基　　金：辽宁省自然科学基金面上基金项目(2022MS450)。

摘　　要：随着汽车工业的发展,先进高强钢的应用越来越广泛。设计了一种低碳含Cr-Mo-Nb-Ti系冷轧复相钢,采用两相区加热—缓冷—过时效热处理工艺,通过光学显微镜(OM)、扫描电镜(SEM)、透射电子显微镜(TEM)、拉伸试验等检测手段,对不同热处理工艺下实验钢的组织与力学性能进行了研究。结果表明:不同热处理工艺下,实验钢组织为铁素体+贝氏体+马氏体;随退火温度的升高,铁素体再结晶程度较高,其内位错密度降低,过冷奥氏体增多,在过时效阶段生成更多的贝氏体;在较低过时效温度下,马氏体部分发生回火,生成回火马氏体。在退火温度800℃、过时效温度350℃工艺下,实验钢具有最理想的再结晶程度与贝氏体/马氏体回火状态,大角度晶界数量占比44.7%,实验钢屈服强度为613 MPa,抗拉强度为799 MPa,扩孔率为67%,拉伸断口呈现尺寸大而深的韧窝,成型性能良好。With the development of the automotive industry,the application of advanced high strength steel has become more and more extensive.A low-carbon cold rolled complex-phase steel containing Cr-Mo-Nb-Ti was designed.Intercritical heating,slow cooling and overaging heat treatment process were adopted.By optical microscope(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and tensile testing machine,the microstructure and mechanical properties of experimental steel under different heat treatment processes were studied.The results show that the microstructure of the experimental steel is ferrite+bainite+martensite under different heat treatment processes.With the increase of annealing temperature,the degree of recrystallization of ferrite is higher,the dislocation density of ferrite decreases,the super-cooled austenite increases,and more bainite is formed in the overaging stage.At lower overaging temperature,martensite is partially tempered to form tempered martensite.Under the annealing temperature of 800 C and overaging temperature of 350 C,the experimental steel has optimum recrystallization degree and bainite/martensite tempering state.The number of large angle grain boundaries accounts for 44.7%,the yield strength of the experimental steel is 613 MPa,the tensile strength is 799 MPa,the hole expansion rate is 67%,and the tensile fracture presents large and deep dimples.The excellent formability of the experimental steel has been obtained.

关 键 词：复相钢 热处理 组织性能 扩孔率 断裂 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156[金属学及工艺—金属材料]