膨胀及原位观测法研究低碳贝氏体钢轨U25CrNi连续冷却相变  

Investigation on Continuous Cooling Transformation Process of Low Carbon Bainite Rail Steel U25CrNi by Dilatation and in-situ Observation Method

作　　者：万菲 刘晓卫 朱敏 闻臻 WAN Fei;LIU Xiao-wei;ZHU Min;WEN Zhen(Central Research Institute of Baoshan Iron and Steel Co Ltd,Wuhan 430080;Ministry of Public Work,China Railway Zhengzhou Bureau Group Co Ltd,Zhengzhou 450052)

机构地区：[1]宝钢股份中央研究院,武汉430080 [2]中国铁路郑州局集团有限公司工务部,郑州450052

出　　处：《特殊钢》2022年第3期79-84,共6页Special Steel

摘　　要：利用Formastor-F淬火膨胀仪热模拟和VL2000DX-SVF17SP高温激光共聚焦显微镜观察,研究了U25CrNi低碳贝氏体钢轨(/%:0.25C,1.73Si,1.69Mn,0.012P,0.002S,1.40Cr,0.57Ni,0.49Mo,0.06V)从950℃以不同冷却速度连续冷却后的膨胀曲线和金相组织。结果表明,低冷速下(0.2℃/s),实验钢组织主要为贝氏体;随冷却速度增大至1℃/s,实验钢组织逐渐过渡为贝氏体和马氏体,且贝氏体板条尺寸随冷速增大而逐渐减小;当冷速达到2℃/s时,冷却过程中基本只发生马氏体相变,实验钢硬度随冷速增大而逐渐增大。By Formastor-F quenching dilatometer themal simulation and VL2000 DX-SVF17 SP high temperature laser scanning confocal microscope(LSCM) observation,the dilatation curve and microstructure of a low carbon bainite rail steel of U25 CrNi(/%:0.25 C,1.73 Si,1.69 Mn,0.012 P,0.002 S,1.40 Cr,0.57 Ni,0.49 Mo,0.06 V) during continuous cooling process from 950 ℃at different cooling rates are studied.The results show that at low cooling rate(0.2 ℃/s),the microstructure of test steel is mainly bainite;as the cooling rate increases to 1 ℃/s,the microstructure gradually transforms to bainite and martensite,and the size of the bainite plate gradually decreases with the increase of the cooling rate;when the cooling rate reaches 2 ℃/s,basically only the martensite transformation occurs during the cooling process,and the hardness of the test steel gradually increases with the increase of the cooling rate.

关 键 词：原位观察 热膨胀法 相变温度 组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程] U213.4[金属学及工艺—金属材料]