Abstract: The steel 0,25C-1.1Cr-O. 7Mn-0. 25Mo-0.05V is melted by 60 t EBT arc fumace-LF-VD-8.4 t ingot casting process. The samples for thermal simulation are cut from 250 mm x 250 mm rolled bloom. The effect of temperature (ambient to 1 200℃) on mechanical properties of steel is tested by Gleeble-3800 thermal-simulated examination, and the continuous cooling transformation curves of steel with cooling speed 0. 1 ~35℃/s are got. And the mechanical properties of 200 mm x 200 mm bloom of steel with normalizing at 920℃, oil quenching at 880 - 900 °C and tempering at 630 〜680 °C by electric resistance furnace and salt bath furnace are examined. Results show that the steel has better hot working property at 900 ~ 1 200 °C ； as the cooling rate is more than 15℃ /s, the bainite + martensite structure could be got； and with normalizing at 920 T , oil quenching at 860℃ and tempering at 650 ~ 680 ℃,the yield strength R_P0.2of steel 525 ~ 570 MPa, tensile strength R_m 710 -745 MPa, elongation A 22% ~23% , longitudinal impact energy (U- 5 mm) 68 ~82 J and transverse impact energy (U_ 5 mm) 65 ~ 76 J are obtained to meet the requirement of standard.

摘要： 0.25C-1.1Cr-0.7Mn-0.25Mo-0.05V钢经60 t EBT电弧炉-LF-VD-8.4 t铸锭流程冶炼。热模拟试样取自250 m/m×250 mm轧坯。通过Gleeble-3800热模拟试验机测试了温度(室温~1 200℃)对钢力学性能的影响,并得出0.1~35℃/s冷却速度下该钢的连续冷却转变曲线。并通过箱式电阻丝炉和盐浴炉测试了200 mm×200 mm坯经920℃正火,880~900℃油淬,630~680℃回火的力学性能。结果表明,该钢在900~1 200℃具有良好的热加工性能;当冷却速度大于15℃/s时可获得贝氏体+马氏体组织;采用920℃正火,880℃油淬,650~680℃回火后,该钢屈服强度R_p0.2为525~570 MPa,抗拉强度R_m为710~745 MPa,伸长率A为22%~23%,纵向冲击功(U-5mm)68~82 J,横向冲击功(U-5 mm)65~76 J,均符合标准要求。

关键词: 高速动车车轴, 0. 25C-1. 1Cr-O. 7Mn-0. 25Mo-0.05V钢, 热塑性, 组织, 力学性能