Vanadium-containing steel for motor train unit axle and heat treatment process thereof

The invention relates to vanadium-containing steel for motor train unit axle and a heat treatment process thereof. The vanadium-containing steel is prepared from, by weight, C 0.24-0.30%, Si 0.20-0.40%, Mn 0.70-1.00%, Cr 0.90-1.20%, Ni 0.70-1.30%, Mo 0.20-0.30%, Cu 0.10-0.60%, Zr 0.01-0.04% V 0.05-0.10%, Ca 0.001-0.005%, P 0.010% or below, S 0.008% or below, [N] 0.0040-0.0070%, T[O] 0.0015% or below, Als 0.015-0.045% and the balance Fe and other inevitable impurities. After special heat treatment, the plasticity and toughness of the steel are obviously better than those of commercial steel, the fatigue limit of the steel is remarkably higher that that of the commercial steel, and the steel has good strength toughness matching and excellent anti-fatigue performance. 本发明涉及种含钒动车组车轴用钢及其热处理工艺，按照重量百分比含有C：0.24～0.30，Si：0.20～0.40，Mn：0.70～1.00，Cr：0.90～1.20，Ni：0.70～1.30，Mo：0.20～0.30，Cu：0.10～0.60，Zr：0.01～0.04，V：0.05～0.10，Ca：0.001～0.005，P≤0.010，S≤0.008，[N]：0.0040～0.0070，T[O]≤0.0015，Als：0.015～0.045，余为Fe和其它不可避免的杂质；经过特殊热处理后其