Abstract: The flowsheet process of U20Mn2SiCrNiMo bainitic rail steel is 150 t BOF-LF-VD-280 mm×380 mm cast bloom-rolling,finishing at 930～980℃,air cooling -340℃ 4 h,air cooling,double tempeing.The microstructure of hotrolled(end rolling at 930～980℃ air cooling)and tempered(320 ℃once-and double-tempering)of U20Mn2SiCrNiMo steel is composed of bainite, martensite and retained austenite.Mechenical properties test results show that the optimum tempering process of U20Mn2SiCrNiMo steel rail is 320℃4 h air cooling+320℃4 hair cooling,double tempeing,its yield strength is 1242 MPa,tensile strength 1393 MPa,HBW hardness 417,elongation 15.0%,reduction of area 60%,impact absorption work K_u2 is 98 J,and longitudinal residual stress of rail bottom +180 MPa.

摘要： U20Mn2SiCrNiMo贝氏体钢轨的生产流程为150 t 转炉-LF-VD-280 mm×380 mm铸坯轧制，终轧930~980 ℃,空冷-340 ℃ 4 h两次回火，空冷。U20Mn2SiCrNiMo钢热轧态(终轧930~980 ℃空冷）和(320 ℃一、二次回火)组织均由贝氏体、马氏体和残余奥氏体组成。力学性能试验结果表明：U20Mn2SiCrNiMo钢轨最佳回火工艺为320 ℃ 4 h空冷+320 ℃ 4 h空冷二次回火，其性能为：屈服强度1242 MPa，抗拉强度1393 MPa，HBW硬度值417，伸长率15.0%，断面收缩率60%，冲击吸收功K_U2 98 J，轨底纵向残余应力+180 MPa。