一种高强韧性高淬透性高速车轴钢,所述车轴钢的屈服强度Rp0.2≥630MPa,抗拉强度Rm≥800MPa,延伸率A≥20％,5mm缺口室温纵向冲击吸收功KU2≥80J,韧脆转变温度低于-40℃；所述钢的化学成分包括B,所述B以重量百分比计为0.0008～0.0025％。同时本发明还提供所述钢的制备方法。本发明充分发挥各元素在车轴钢中的作用,获得晶粒细小且以马氏体为主的显微组织。采用两次淬火+高温回火热处理可以获得均匀的细晶奥氏体晶粒及Nb微合金纳米第二相增强的马氏体组织,实现高强度、高韧性和高淬透性的优异匹配,最终使高速车轴具有良好的抗冲击、抗疲劳等服役性能、优异的强韧性匹配和良好的淬透性。

A high-speed axle steel with high strength and toughness and high hardenability, the yield strength of the axle steel Rp0.2≥630MPa, tensile strength Rm≥800MPa, elongation A≥ 20%,5mm notch room temperature longitudinal impact absorption work KU2≥80J, toughness and brittle-transition temperature below -40℃; The chemical composition of the steel includes B, which is 0.0008 ~ 0.0025% by weight percentage. The invention also provides a preparation method of the steel. The invention gives full play to the role of each element in axle steel and obtains fine grain and martensitic microstructure. Using two high temperature quenching and tempering heat treatment can obtain uniform fine-grain austenite grain and Nb micro alloy nano second phase enhanced martensite structure, to achieve high strength, high toughness and high hardenability of excellent match, eventually make the high-speed axle has good shock resistance, fatigue resistance and so on service performance, excellent toughness match and good hardenability.