热处理对微纳结构低温贝氏体钢组织与力学性能的影响  

Effect of heat treatment on microstructure and mechanical properties of low temperature bainitic steel with micro-/nano-structure

作　　者：钟磊[1] 吴开明[1] 董航宇 周雯[1] 顾丽媛[1] ZHONG Lei;WU Kai-ming;DONG Hang-yu;ZHOU Wen;GU Li-yuan(International Research Institute for Steel Technology,Wuhan University of Science and Technology,Wuhan 430080,China)

机构地区：[1]武汉科技大学国际钢铁研究院

出　　处：《材料热处理学报》2018年第10期52-58,共7页Transactions of Materials and Heat Treatment

基　　金：湖北省自然科学基金创新群体(2016CFA004)

摘　　要：设计了一步和两步贝氏体等温转变工艺及贝氏体等温转变＋深冷处理工艺,通过电子背散射衍射（EBSD）、扫描电镜（SEM）、X射线衍射分析（XRD）和拉伸实验等方法,对比分析了不同热处理工艺对低温贝氏体钢微观组织与力学性能的影响。结果表明：与一步贝氏体转变相比,两步贝氏体转变和深冷处理工艺均可有效细化块状残留奥氏体,降低残留奥氏体体积分数,减小平均有效晶粒尺寸;深冷处理工艺可以进一步提高试验钢的硬度,冲击韧性相应有所下降;两步贝氏体工艺的贝氏体铁素体板条平均尺寸更小,具有更多的薄膜状残留奥氏体,获得了最佳的综合力学性能。One-step and two-step bainitie isothermal transformation process and bainitie isothermal transformation plus cryogenic treatment were designed. The effects of different heat treatments on microstructure and mechanical properties of low temperature bainite steel were investigated by means of electron-backscattered diffraction（EBSD） technique, scanning electron microscopy（SEM）, X-ray diffraction（XRD） and tensile test. The results show that compared with one-step bainite isothermal transformation process, two-step bainite isothermal transformation and cryogenic treatment can effectively refine the bulk retained austenite, reduce the volume fraction of the residual austenite and decrease the average effective grain size. Cryogenic treatment can significantly increase the surface hardness of the steel, but decreases the impact toughness accordingly. The bainitic ferrite laths of the steel treated by two-step bainite isothermal transformation process have smaller average size and more film-like retained austenite, which leads to the best comprehensive mechanical properties of the steel.

关 键 词：低温贝氏体钢 两步贝氏体转变 深冷处理 残留奥氏体 力学性能 

分 类 号：TG142.2[一般工业技术—材料科学与工程]