Abstract: The continuous cooling transformation ( CCT) curves of U75V steel (/% ； 0. 75C, 0. 63Si, 0. 95Mn, 0. 025P,0. 004S,0. 26Cr,0. 05V) are measured by a Gleeble-3500 thermal simulation testing machine, and the calculated model for temperature field and structure transformation of 60AT rail during air-cooling process after rolling is established by using DEFORM-3D finite element software to study and analyze the effect of temperature and structure on bending deformation of 60AT rail during 150 ~700 s air-cooling process after rolling. Results show that the effect of great volume to surface- area ratio of rail waist of 60 AT rail on distribution of temperature at whole rail section is larger, with rail air-cooling for 150 s, there is no phase transformation at section of 60AT rail and the structure is all austenite, with temperature dropping i. e. air cooling for 650 s, the 97. 2 % austenite at rail section transfers to pearlite, besides the effect of structure transformation on bending deformation of rail is larger, at end air-cooling the bending deflection of rail in K-direction (lateral bending) is -0. 07 mm, i. e. the bending is toward rail bottom short edge, and the bending deflection of rail in Z-direction (positive bending) is 0. 228 mm, i. e. the bending is toward rail head. The calculation results are available for reference of pre-bending in rail straightening process.

摘要： 通过Gleeble-3500热模拟试验机测定了U75V钢（/%:0.75C,0.63Si,0.95Mn,0.025P,0.004S,0.26Cr,0.05V）的CCT相变曲线,利用DEFORM-3D有限元软件,通过建立60AT钢轨轧后空冷过程中温度场、组织转变计算模型,研究分析了60AT钢轨150~700 s轧后空冷过程中温度、组织对弯曲变形的影响。结果表明,60AT钢轨具有的大体表比轨腰对钢轨整体断面温度分布影响较大,钢轨空冷150 s时,60AT钢轨断面上还未发生相变,组织全部为奥氏体,随着温度的降低,空冷650 s时,钢轨断面基本上珠光体转变量为97.2%,同时,弯曲变形受组织转变影响较大,终冷时,钢轨在Y方向（侧弯）弯曲挠度-0.07 mm,即弯向轨底短边,在Z方向（正弯）弯曲挠度为0.228 mm,即弯向轨头,计算结果为钢轨矫直过程中的预弯提供参考。