Cr和Si含量对重载铁路用75 kg·m^(-1)U77MnCrH钢轨组织与性能的影响  

Effect of Cr and Si Contents on the Structure and Properties of 75 kg·m^(-1)U77MnCrH for Heavy-Haul Railway

作　　者：金纪勇 王冬[1,2] 于海鑫 桂林[1,2] 张瑜 刘丰收 JIN Jiyong;WANG Dong;YU Haixin;GUI Lin;ZHANG Yu;LIU Fengshou(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan Liaoning 114009,China;Technical Center,Ansteel Group Co.,Ltd.,Anshan Liaoning 114009,China;Metals&Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,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]鞍钢股份有限公司技术中心,辽宁鞍山114009 [3]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081

出　　处：《中国铁道科学》2024年第5期13-21,共9页China Railway Science

基　　金：国家重点研发计划项目(2021YFB2601000)。

摘　　要：为开发适应重载铁路用高强韧、高硬度耐磨钢轨,按照C-Si-Mn-Cr成分设计体系进行U77MnCrH钢轨钢的成分设计和中试试验;基于中试试验的组织性能,筛选出组织性能较好的试验钢进行75 kg·m^(-1)U77MnCrH钢轨试制试验;使用金相显微镜、场发射扫描电子显微镜、透射电子显微镜、万能拉伸试验机及硬度计对75 kg·m^(-1)U77MnCrH钢轨试样进行组织性能分析。结果表明:随着Cr含量由0.26%增加到0.38%,钢轨钢试样中珠光体片层间距由165 nm减小到146 nm,抗拉强度和硬度均有提高,屈服强度R_(p0.2)与断后伸长率均有降低;随着Si含量由0.25%增加到0.45%,珠光体片层间距由165 nm减小到132 nm,断后伸长率和硬度均有提高,屈服强度R_(p0.2)明显增加,抗拉强度变化不大;0.45%的Si配合0.26%的Cr获得的钢轨珠光体更加均匀细小,片层间距分布更加均匀,力学性能与硬度匹配更好,抗拉强度达到1258 MPa,屈服强度R_(p0.2)达到845 MPa,断后伸长率达到13.0%,轨头顶面硬度达384 HBW,横断面硬度介于36.2~38.8 HRC。75 kg·m^(-1)U77MnCrH钢轨的各项指标对生产实践具有较强的参考价值。To develop high-strength,high-toughness and high-hardness wear-resistant rails for heavy-haul railways,the composition design and intermediate pilot test of U77MnCrH rail steel were conducted according to the C-Si-Mn-Cr compositional design system.Based on the microstructure and properties of the intermediate pilot test,steel with better microstructure and properties was selected for 75 kg·m^(-1)U77MnCrH rail rolling test.The microstructure and properties of 75 kg·m^(-1)U77MnCrH rail samples were studied using optical microscope,field emission scanning electron microscope,transmission electron microscope,a universal tensile testing machine and a hardness tester.The results show that as the content of chromium increases from 0.26%to 0.38%,the lamellar spacing of pearlite decreases from 165 nm to 146 nm,accompanied by an increase in tensile strength and hardness,but a decrease in yield strength R_(p0.2)and elongation at fracture.As the content of silicon increases from 0.25%to 0.45%,the lamellar spacing of pearlite decreases from 165 nm to 132 nm,resulting in increased elongation at fracture and hardness,as well as a notable increase in yield strength R_(p0.2),while the tensile strength remains relatively unchanged.The pearlite of rail steel with 0.45%silicon and 0.26%manganese is more uniform and finer with a more homogeneously distribution of lamellar spacing,achieving an optimal balance between mechanical properties and hardness.It demonstrates a tensile strength of 1,258 MPa,a yield strength R_(p0.2)of 845 MPa,an elongation at fracture of 13.0%,hardness of rail head top surface of 384 HBW,and a cross-sectional hardness ranging from 36.2 to 38.8 HRC.The various indicators of the 75 kg·m^(-1)U77MnCrH rail provide valuable references for production practice.

关 键 词：重载铁路 75 kg·m^(-1)U77MnCrH钢轨 透射电子显微镜 万能拉伸试验机 珠光体 

分 类 号：U213.92[交通运输工程—道路与铁道工程]