0.25C-1.1Cr-0.7Mn-0.25Mo-0.05V高速动车车轴用钢的热塑性、组织和力学性能

Hot Plasticity,Structure and Mechanical Properties of Steel 0.25C-1.1Cr-0.7Mn-0.25Mo-0.05V for High-Speed Train Axle Shaft

0.25C-1.1Cr-0.7Mn-0.25Mo-0.05V钢经60t 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Rp0.2为525~570 MPa,抗拉强度Rm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-5mm）65~76J,均符合标准要求。

The steel 0.25C-1.1Cr-0.7Mn-0.25Mo-0.05 V is melted by 60 t EBT arc furnace-LF-VD-8.4 t ingot casting process.The samples for thermal simulation are cut from 250 mm × 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 of200 mm × 200 mm bloom of steel with normalizing at 920 ℃,oil quenching at 880 ~ 900 ℃ and tempering at 630 ~ 680 ℃by electric resistance furnace and salt bath furnace are examined.Results show that the steel has better hot working property at 900 ~ 1 200 ℃;as the cooling rate is more than 15 ℃/s,the bainite ＋martensite structure could be got;and with normalizing at 920 ℃,oil quenching at 860 ℃ and tempering at 650 ~ 680 ℃,the yield strength Rp0.2 of 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.