U76CrRE钢轨热处理过程组织控制及性能  

Microstructure control and properties of U76CrRE steel rail during heat treatment

作　　者：王慧军 涛雅[1] 陈林[2] 梁正伟[1] 王永明[1] Wang Huijun;Tao Ya;Chen Lin;Liang Zhengwei;Wang Yongming(Technology Center,Inner Mongolia Baotou Steel Union Co.,Ltd.,Baotou Inner Mongolia 014010,China;School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China)

机构地区：[1]内蒙古包钢钢联股份有限公司技术中心,内蒙古包头014010 [2]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《金属热处理》2022年第5期161-165,共5页Heat Treatment of Metals

摘　　要：通过对U76CrRE钢轨热处理时的冷却工艺进行优化,消除了钢轨脱碳层中的异常上贝氏体组织。对异常组织产生的原因进行了分析,提出了U76CrRE钢轨的最佳热处理工艺。在分段冷却过程中,U76CrRE钢轨的强冷介入温度在568℃。钢轨内部相变潜热与表面急冷层容易在钢轨脱碳层内形成等温层,是异常上贝氏体组织产生的温度条件;同时,钢轨近表面晶界处严重脱碳为上贝氏体组织形成提供了化学成分条件。U76CrRE钢轨的最佳热处理工艺为淬火开冷温度780℃,淬火时间120 s(20 s+100 s),淬火终冷温度控制在410℃,返温温度控制在540℃。Cooling process of the U76 CrRE steel rail during heat treatment was optimized, and the abnormal upper bainite microstructure in the decarburization layer of the steel rail was therefore eliminated. The causes of abnormal microstructure were analyzed, and the best heat treatment process of U76 CrRE steel rail was put forward. During the stage cooling process, the forced cooling intervention temperature of U76 CrRE steel rail is 568 ℃. The temperature condition for the abnormal upper bainite microstructure is that the latent heat of phase transformation inside the rail and the extremely cold surface layer easily form an isothermal layer in the decarburization layer of the rail. Simultaneously, severe decarburization at the grain boundary near surface of the rail provides the condition of chemical composition for the formation of upper bainite structure. The optimum heat treatment process of the U76 CrRE steel rail consists of quenching cooling starting temperature of 780 ℃, quenching time of 120 s(20 s+100 s), quenching final cooling temperature of 410 ℃ and back temperature of 540 ℃.

关 键 词：U76CrRE钢轨 热处理 组织控制 脱碳层 

分 类 号：TG156.8[金属学及工艺—热处理]