激光离散淬火钢轨的滚动接触疲劳磨损性能

采用激光离散处理对钢轨表面进行了强化,旨在提高钢轨的使用寿命。研究了3种不同分布形式的激光离散淬火工艺,利用滚动接触疲劳磨损试验机测定了钢轨的疲劳磨损性能,并对磨损表面形貌、截面形貌以及磨损机理进行了分析。结果表明:未处理钢轨试样表面发生塑性变形和疲劳剥落,产生严重的波磨,磨损量1.102 g;激光离散淬火强化后,波磨消失,磨损量显著降低,但是在试样边缘和淬火区界面有裂纹产生;当淬火区以间隔1 mm、倾斜60°分布时,试样中心的界面裂纹得到有效控制,磨损量最低,相比未处理试样减少了63%;通过缩小淬火区间隔,增大淬火区倾斜角度,可以有效提高激光离散淬火层的裂纹抗性和磨损性能。

Rolling contact fatigue property of laser dispersed quenched steel rail

Laser dispersed quenched process was carried out on steel rail surface in order to improve the service life of the rail. Three different distribution patterns for the laser dispersed quenched were used, and rolling contact fatigue wear test machine was used to measure the fatigue wear property of the rail, and the wear surface morphology, cross-sectional morphology and wear mechanism were analyzed. The results show that the wear loss of original state specimen is 1.102 g, and fatigue spall and plastic deformation with severe corrugation occur on the surface of the original specimen. After laser dispersed quenched process, the corrugation is eliminated, and the wear loss of rail specimen reduces significantly, but cracks occur at the edge of contact zone and the interface of laser hardened region. The cracks at the center of contact zone can be effectively removed when the hardened regions are distributed with 1 mm spacing and 60° inclination, and the lowest wear loss is acquired at this condition, which decreases by 63% compared with that of the original state specimen. It can effectively improve the cracking resistance and wear property of the laser dispersed hardened layer by combination of reducing the spacing and increasing the tilt angle of laser hardened region.