碳、硅含量对重载车轮钢显微组织的影响

Effect of C and Si Contents on Microstructure of Wheel Steel for Heavy Haul Trains

利用金相显微术、扫描电镜、透射电镜以及X射线衍射测量技术研究碳、硅含量对重载车轮钢显微组织的影响。结果表明:重载车轮钢的显微组织由珠光体和少量先共析铁素体组成,适当降低碳含量、增加硅含量不仅使珠光体含量减少,而且导致珠光体的片层间距增大;与珠光体团内层片状组织相比,珠光体团界处的渗碳体不再呈片状、而是以颗粒状不连续分布,同时渗碳体含量相对较少。

The effect of C and Si contents on the microstructure of heavy haul wheel steels was investigated by means of metallographic microscopy, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD） mersurement technique. It is found that the microstructure of wheel steel for heavy haul trains is composed of pearlite and minor proeutectoid ferrite. The decrease of C content and increase of Si content leads to not only a decline in pearlite amount but also an enlargement of pearlite interlaminar spacing. Compared with the lamellar microstructure in pearlite colonies, granular cementite particles distribute discontinuously along the boundaries of pearlite colonies instead of cementite lamellae. In contrast, the amount of cementite near the boundaries is less than that in pearlite colonies.