U71Mn钢轨成形铣削表面完整性实验研究

Experimental investigation on the surface integrity of U71Mn rail via form-milling

  • 摘要: 钢轨成形铣削是一种典型的表面修复技术并且能显著提升轮/轨接触性能,而当前对钢轨成形铣削后的表面完整性尚缺少系统性研究。为此,基于钢轨铣削实验台研究铣削参数(铣削速度、每齿进给量和径向切削深度)对U71Mn钢轨成形铣削后表面完整性的影响。研究结果表明,铣削速度提高50%导致表面粗糙度Ra和Rz分别降低22.01%和15.24%,亚表面塑性变形层厚度减少7 μm;当每齿进给量增大到0.5 mm/z时,Ra和Rz分别增大53.43%和28.65%,亚表面塑性变形层厚度增大15 μm;将径向切削深度增大到0.3 mm导致Ra和Rz分别增大62.43%和26.85%,亚表面塑性变形层厚度增大13 μm。增大铣削速度、减小每齿进给量和径向切削深度均会提升微观形貌质量。实验参数条件下显微硬度均随着距已加工表面距离的增大呈现先降低后平稳的趋势。

     

    Abstract: Rail form-milling is a typical surface repair technique and can significantly improve wheel/rail contact performance. However, the surface integrity of rail via form-milling has not been systematically studied at present. Therefore, the influence of milling parameters (i.e., milling speed, feed per tooth and radial depth of cut) on the surface integrity of U71Mn rail after form-milling is studied based on rail form-milling test bench. The results show that the surface roughness Ra and Rz decrease by 22.01% and 15.24%, respectively, and the thickness of subsurface plastic deformation layer decreases by 7 μm when milling speed increases by 50%. When the feed rate per tooth increases to 0.5 mm/z, Ra and Rz increase by 53.43% and 28.65%, respectively, and the thickness of subsurface plastic deformation layer increases by 15 μm. Increasing the radial depth of cut to 0.3 mm results in an increase in Ra and Rz of 62.43% and 26.85%, respectively, and an increase in subsurface plastic deformation layer thickness of 13 μm. Increasing milling speed, reducing feed per tooth and radial depth of cut can improve the quality of the micro-morphology. Under the experimental parameters, the microhardness decreases at first and then remains stable with the increase of the distance from the machined surface.

     

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