高速铁路新材料

通过研究表面超声滚压不同加工参数对DZ2车轴钢表面完整性及表面性能的影响规律，为DZ2车轴钢超声表面滚压处理选取最优工艺方案。研究结果表明：通过超声表面滚压处理后，DZ2试样的表面状态得到改善，表面性能得到大幅度提高。试样表面粗糙度降低，表面显微硬度增加，轴向表面残余提升；周向的表面残余应力变化幅度较小。表层出现明显的塑性流变，同时表层组织中发生铁素体晶粒的拉长以及渗碳体的碎化现象。不同的工艺参数对材料表面状态影响不同，随着主轴转速的增加，表面粗糙度值逐渐减小，表面轴向残余应力得到大幅度提高；随着静压力的增大，表面硬度的数值不断增大。通过合理组合不同的加工参数，可以使得DZ2车轴钢表面完整性及表面性能得到较好的改善，提出最佳优化参数组合建议。

By studying the influence of different processing parameters of ultrasonic surface rolling on the surface integrity and surface properties of DZ2 axle steel, the optimal process scheme for ultrasonic surface rolling treatment of DZ2 axle steel was selected. The results show that: the surface state of DZ2sample is improved and its surface properties are greatly improved after ultrasonic surface rolling treatment. The surface roughness decreases and the surface microhardness increases. The axial surface residual is increased, the circumferential surface residual stress changes slightly. There is obvious plastic rheology on the surface, and the ferrite grain elongation and cementite fragmentation in the surface tissue.Different process parameters have different effects on the surface state of the material. With the increase of the spindle speed, the surface roughness value decreases gradually, and the axial residual stress on the surface increases greatly. With the increase of static pressure, the value of surface hardness increases.By reasonable combination of different processing parameters, surface integrity and surface properties of DZ2 axle steel can be improved, and the optimal parameter combination is proposed.