铬对BVRE重轨钢组织和强度的影响

Effects of Chromium on the Microstructure and Strength of BVRE Heavy Rail Steel

以BVRE重轨钢为研究对象,通过真空感应炉冶炼及锻造和轧制工艺制备出成分合格的洁净重轨钢试样,利用金相显微镜、扫描电子显微镜、综合力学性能测定仪等测试手段,系统研究了铬对重轨钢珠光体组织和强度的影响作用。金相分析表明,随着铬含量增加,重轨钢的珠光体片层间距逐渐减小,珠光体球团尺寸逐渐增加;在w(Cr)=0.40%时珠光体片层间距达到最小值139nm。拉伸实验结果表明,当w(Cr)由0.21%增加到0.40%时,重轨钢的抗拉强度和屈服强度均被显著提高,抗拉强度由1 073 MPa增加到1133 MPa,屈服强度由610 MPa增加到688 MPa。

The BVRE heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects of chromium on the pearlite and strength of heavy rail steel were systematically investigated by metallographic microscope, SEM, integrated mechanical testing machine and so on. Metallographic analysis show that, with increasing of chromium content, pearlite interlamellar spacing of heavy rail steel is decreased obviously and the pearlite colony size is increased gradually; when the chromium content is 0.40%, the paerlite interlamellar spacing of heavy rail steel reaches the minimum of 139 nm. Tensile test indicates that, with increasing of chromium content, both tensile strength and yield strength are improved notably; when the chromium content is increased from 0.21% to 0.40%, the tensile strength is improved from 1 073 MPa to I 133 MPa and the yield strength is from 610 MPa to 688MPa.