摘要
百米U75V钢轨是我国铁路建设的主型钢轨,在线热处理是其主要强韧化手段,纵向(长度方向)性能均匀性差和生产效率低是其热处理生产存在的主要问题。百米U75V钢轨的在线热处理过程分为2个冷却阶段,共包含4个冷却工艺参数:开淬温度(T_(i))、相变阶段冷却速度(V_(s))、相变冷却结束温度(T_(f))以及相变后冷却速度(V_(a))。通过热模拟试验研究了各参数对百米U75V钢轨组织和性能的影响。随着工艺参数的变化,珠光体片层间距(S)在100.7~209.1 nm范围内变化;T_(i)和V_(s)对S具有特别显著影响,T_(f)和V_(a)对S没有显著影响;T_(i)不一致是百米U75V钢轨纵向性能不均匀的主要原因之一。采用“先慢后快”的两段式冷却方案,即在轧后钢轨表面温度冷却至相变终冷温度(约500℃)之前,以接近但不超过珠光体转变临界冷却速率的速度进行冷却,之后提高冷却速度(不超过10℃/s),有利于同时提高生产效率和百米U75V钢轨纵向性能的均匀性。
The 100 meter U75V steel rail is the main type of rail in China′s railways,and online heat treatment is the main strengthening and toughening method.The poor uniformity of longitudinal(length direction)performance and low production efficiency are the bottleneck problems in the heat treatment production.The online heat treatment process of the 100 meter U75V steel rail is divided into two cooling stages,consisting of four cooling parameters,which are the initial quenching temperature(T_(i)),the cooling rate in the phase transformation stage(V_(s)),the final cooling temperature of phase transformation(T_(f))and the cooling rate after phase transformation(V_(a)).The influence of each parameter on the microstructure and properties of 100 meter U75V steel rail is studied through thermal simulation experiments.The interlayer spacing(S)of pearlite varies within the range of 100.7 to 209.1 nm as the process parameters change.T_(i)and V_(s)have a particularly significant impact on S,while T_(f) and V_(a)have no significant impact.T_(i)inconsistency is one of the main reasons for the uneven longitudinal performance of the 100 meter U75V steel rail.The two-stage cooling procedure of"slow first and fast later"is proposed,which takes the critical cooling rate of pearlite transformation before the surface temperature of the rolled steel rail cools to the final cooling temperature of phase transformation(about 500℃),and then increasing the cooling rate(not exceeding 10℃/s),which is beneficial for improving production efficiency and the uniformity of the longitudinal performance of the 100 meter U75V steel rail.
作者
陈科澎
汪洋
张惠泽英
宋华
高明昕
CHEN Kepeng;WANG Yang;ZHANG Huizeying;SONG Hua;GAO Mingxin(School of Mechanical Engineering and Automation,University of Science and Technology Liaoning,Anshan 114051,Liaoning,China;School of Innovation and Entrepreneurships,University of Science and Technology Liaoning,Anshan 114051,Liaoning,China)
出处
《热处理技术与装备》
2024年第2期7-11,17,共6页
Heat Treatment Technology and Equipment
基金
辽宁省教育厅面上项目(JYTMS20230951)。
关键词
百米U75V钢轨
在线热处理
工艺参数
组织
性能
100 meter U75V rail
online heat treatment
cooling parameters
microstructure
properties
