工程科学学报，第38卷，第8期：1115-1122,2016年8月 Chinese Journal of Engineering,Vol.38,No.8:1115-1122,August 2016 D0l:10.13374/j.issn2095-9389.2016.08.010:http://journals..ustb.edu.cn TMCP工艺对Si-Mn系贝氏体钢组织与性能的影响 李明保四，胡水平 北京科技大学治金工程研究院，北京100083 ☒通信作者，E-mail:limingbaole6@163.com 摘要研究了轧后中温缓慢冷却与中温等温两种不同的热机械控制工艺(thermomechanical control process,TMCP)对硅锰 系贝氏体钢的组织与性能的影响.通过拉伸试验机测试试验钢的力学性能，利用扫描电子显微镜、电子背散射衍射等分析手 段对试验钢进行显微组织结构分析，并利用X射线衍射测定残余奥氏体含量.结果表明：随着轧后连续缓慢冷却开始温度的 升高，贝氏体钢的抗拉强度、硬度及拉伸应变硬化指数值有所提高，伸长率和冲击韧性降低，屈强比先降低后升高.随着轧 后等温时间的延长，贝氏体钢的抗拉强度与屈强比先降低后升高，伸长率及冲击韧性先升高后降低.相对于等温制度，连续 缓慢冷却可得到更好的综合力学性能，强塑积明显高于前者，伸长率比前者高20%以上 关键词贝氏体钢：热机械处理：显微组织：力学性能 分类号TG142.1 Effect of TMCP on the microstructure and mechanical properties of Si-Mn series bainitic steel LI Ming-bao HU Shui-ping Engineering Research Institute,University of Science and Technology Beijing,Beijing 100083,China Corresponding author,E-mail:limingbaol6@163.com ABSTRACT The effects of two different thermomechanical control processes (TMCP)including medium temperature slow cooling and medium temperature isothermal treatment after rolling on the microstructure and mechanical properties of Si-Mn series bainitic steel were investigated in this paper.The mechanical properties of the steel were studied by a tensile testing machine,the microstruc- ture was characterized by means of scanning electron microscopy and electron backscatter diffraction,and the amount of retained austenite in the steel was determined by X-ray diffraction analysis.The results show that,as the starting slow cooling temperature after rolling rises,the tensile strength,hardness and tensile strain hardening exponent n increase,the elongation rate and the impact tough- ness decrease,and the yield-strength ratio decreases first and then increases.When the isothermal time after rolling extends,the tensile strength and the yield-strength ratio of the steel first decrease and then increase,but the elongation and the impact toughness have a reverse trend.Compared with the isothermal regime,the continuous slow cooling can get better comprehensive mechanical prop- erties,the product of tensile strength and elongation is higher,and the elongation is 20%higher than that of the former. KEY WORDS bainitic steels:thermomechanical treatment;microstructure;mechanical properties 贝氏体钢具有良好的综合力学性能，受到人们的 刘东雨等四研发出Mn-B系空冷贝氏体钢.Mn可以 广泛关注.20世纪30年代初，美国科学家Bain等首 大幅度降低Bs点，且可以降低生产成本.Caballero 先发现贝氏体组织.随后，康沫狂等四在Mo-B系和 等B则研究结果显示，无碳贝氏体钢在抗拉强度达到 Mo系贝氏体钢以及贝氏体相变方面做出杰出贡献. 1600~1800MPa的同时，伸长率仍可以保持在10%以 收稿日期：2015-08-02 基金项目：国家自然科学基金资助项目(51274036)工程科学学报，第 38 卷，第 8 期: 1115--1122，2016 年 8 月 Chinese Journal of Engineering，Vol． 38，No． 8: 1115--1122，August 2016 DOI: 10． 13374 /j． issn2095--9389． 2016． 08． 010; http: / /journals． ustb． edu． cn TMCP 工艺对 Si--Mn 系贝氏体钢组织与性能的影响 李明保，胡水平 北京科技大学冶金工程研究院，北京 100083  通信作者，E-mail: limingbao16@ 163． com 摘 要 研究了轧后中温缓慢冷却与中温等温两种不同的热机械控制工艺( thermomechanical control process，TMCP) 对硅锰 系贝氏体钢的组织与性能的影响． 通过拉伸试验机测试试验钢的力学性能，利用扫描电子显微镜、电子背散射衍射等分析手 段对试验钢进行显微组织结构分析，并利用 X 射线衍射测定残余奥氏体含量． 结果表明: 随着轧后连续缓慢冷却开始温度的 升高，贝氏体钢的抗拉强度、硬度及拉伸应变硬化指数 n 值有所提高，伸长率和冲击韧性降低，屈强比先降低后升高． 随着轧 后等温时间的延长，贝氏体钢的抗拉强度与屈强比先降低后升高，伸长率及冲击韧性先升高后降低． 相对于等温制度，连续 缓慢冷却可得到更好的综合力学性能，强塑积明显高于前者，伸长率比前者高 20% 以上． 关键词 贝氏体钢; 热机械处理; 显微组织; 力学性能 分类号 TG142. 1 Effect of TMCP on the microstructure and mechanical properties of Si--Mn series bainitic steel LI Ming-bao ，HU Shui-ping Engineering Ｒesearch Institute，University of Science and Technology Beijing，Beijing 100083，China  Corresponding author，E-mail: limingbao16@ 163． com ABSTＲACT The effects of two different thermomechanical control processes ( TMCP) including medium temperature slow cooling and medium temperature isothermal treatment after rolling on the microstructure and mechanical properties of Si--Mn series bainitic steel were investigated in this paper． The mechanical properties of the steel were studied by a tensile testing machine，the microstruc￾ture was characterized by means of scanning electron microscopy and electron backscatter diffraction，and the amount of retained austenite in the steel was determined by X-ray diffraction analysis． The results show that，as the starting slow cooling temperature after rolling rises，the tensile strength，hardness and tensile strain hardening exponent n increase，the elongation rate and the impact tough￾ness decrease，and the yield--strength ratio decreases first and then increases． When the isothermal time after rolling extends，the tensile strength and the yield--strength ratio of the steel first decrease and then increase，but the elongation and the impact toughness have a reverse trend． Compared with the isothermal regime，the continuous slow cooling can get better comprehensive mechanical prop￾erties，the product of tensile strength and elongation is higher，and the elongation is 20% higher than that of the former． KEY WOＲDS bainitic steels; thermomechanical treatment; microstructure; mechanical properties 收稿日期: 2015--08--02 基金项目: 国家自然科学基金资助项目( 51274036) 贝氏体钢具有良好的综合力学性能，受到人们的 广泛关注． 20 世纪 30 年代初，美国科学家 Bain 等首 先发现贝氏体组织． 随后，康沫狂等［1］在 Mo--B 系和 Mo 系贝氏体钢以及贝氏体相变方面做出杰出贡献． 刘东雨等［2］研发出 Mn--B 系空冷贝氏体钢． Mn 可以 大幅度 降 低 Bs 点，且 可 以 降 低 生 产 成 本． Caballero 等［3--4］研究结果显示，无碳贝氏体钢在抗拉强度达到 1600 ～ 1800 MPa 的同时，伸长率仍可以保持在 10% 以