高速动车组新材质车轮性能研究

摘要

为提高高速铁路动车组车轮的强度、硬度,同时兼顾其韧性,进行新材质车轮的成分设计及试样制备;对试样的化学成分、拉伸性能、断面硬度、断裂韧性、淬透性进行测试,对其金相组织、微观组织和析出物进行观测,综合分析新材质车轮的性能,并与ER8车轮进行对比.结果表明:与ER8车轮相比,新材质车轮中C的质量分数相同,Mn的质量分数按常规设定,但提高Si的质量分数并添加V,使其抗拉强度提高9％,屈服强度提高12％,硬度提高15 HBW,断裂韧性提高10％,断后伸长率、冲击韧性和淬透性相当;相同踏面深度下,新材质车轮珠光体团更细、珠光体片层间距更小、先共析铁素体体积分数更高;提高Si的质量分数并添加V,还使新材质车轮的微观组织结构和分布发生改变,是其具有更高的强度、硬度和断裂韧性的直接原因.%In order to improve the strength and hardness of wheels for high speed EMU,taking into account the toughness at the same time,the chemical composition design of new material wheel and the preparation of samples were carried out.The chemical composition,tensile property,section hardness,fracture toughness and hardenability of the sample were tested.The metallographic structure,microstructure and precipitates were observed.The performance of the new material wheel was analyzed and compared with the ER8 wheel.Results show that,by means of increasing the mass fraction of Si and adding V in the new material wheel with the same mass fraction of C and the mass fraction of Mn as usual,compared with the ER8 wheel,the values of tensile strength,yield strength,hardness and fracture toughness of new material wheel are increased about 9％,12％,15 HBW and 10％ respectively.The values of elongation,impact toughness and hardenability are equal to those of the ER8 wheel.Under the same tread depth,the pearlite colony of the new material wheel is finer,the pearlite lamellar spacing is smaller and the volume fraction of the proeutectoid ferrite is higher.Increasing the mass fraction of Si and adding V in the new material wheel can also change its microstructure and distribution,which is the direct reason for its higher strength,hardness and fracture toughness.