Nb对2000 MPa桥索钢再加热过程中组织变化的影响  

Effect of Nb on microstructure transformation in reheating process of 2 000 MPa bridge cable steel

作　　者：冯路路 吴开明[1] 李萍萍 陈姝敏 鲁修宇 乔文玮 FENG Lu-lu;WU Kai-ming;LI Ping-ping;CHEN Shu-min;LU Xiu-yu;QIAO Wen-wei(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Collaborative Innovation Center for Advanced Steels,International Research Institute for Steel Technology,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;School of Mechanical Engineering,Jing Chu University of Technology,Jingmen 448000,Hubei,China;Jiangsu Huaneng Cable Co.,Ltd.,Gaoyou 225613,Jiangsu,China;Research Institute of Wuhan Iron and Steel Group,Wuhan 430080,Hubei,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,高性能钢铁材料及其应用省部共建协同创新中心,国际钢铁研究院,湖北武汉430081 [2]荆楚理工学院机械工程学院,湖北荆门448000 [3]江苏华能电缆股份有限公司,江苏高邮225613 [4]武汉钢铁(集团)研究院,湖北武汉430080

出　　处：《钢铁研究学报》2020年第1期60-65,共6页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(U153226,51671149);国家重点研发计划资助项目(2017YFB0304800);国家外专局高等学校学科创新引智111计划资助项目(2019BJH026)。

摘　　要：针对不同Nb含量的2种桥索钢,采用热膨胀仪、光学显微镜、扫描电子显微镜和硬度测试仪对其在箱式电阻炉连续加热过程中的组织演变和水冷淬火后的硬度进行了对比分析。结果表明:Nb元素可以细化桥索钢的原始组织,使其存在大量的铁素体和渗碳体的晶界,在连续加热过程中的开始阶段提供更多的奥氏体形核位置,使得奥氏体逆共析转变的起始温度降低,而终了温度升高,逆共析转变区域增大。同时,Nb元素形成的碳化物在加热阶段对奥氏体晶粒的长大具有拖拽作用,降低桥索钢在奥氏体形核后的长大速度,使得淬火后得到马氏体的硬度值降低,因此需要较高的温度来溶解合金碳化物使桥索钢充分奥氏体化。The microstructure transformation and hardness after quenching of two kinds of bridge cable steels with different Nb contents during continuous heating in box resistance furnace were analyzed by means of thermal expansion instrument, optical microscope and scanning electron microscope and hardness tester. The results show that Nb element can refine the microstructure of bridge cable steel and make it contain a large number of ferrite and cementite grain boundaries, providing more austenite nucleation sites at the beginning of continuous heating, reducing the starting temperature and rising end temperature of the reverse eutectoid transformation, and enlargement of reverse eutectoid transformation region. At the same time, carbides formed by Nb element drag the growth of austenite grains during heating, decrease the growth rate of the bridge cable steel after austenite nucleation. The hardness value of martensite obtained after quenching decreases, therefore, higher temperature is needed to dissolution alloy carbides to fully austenite bridge cable steel.

关 键 词：NB含量 桥索钢 加热过程 显微组织 奥氏体 

分 类 号：TG142.1[一般工业技术—材料科学与工程]