【作者】 钟雯；

【导师】 刘启跃；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2011， 博士

【摘要】 随着我国重载与高速铁路的快速发展,轮轨由于滚动接触疲劳与磨损引起的失效损伤变得越来越严重,已成为影响铁路运输安全的重要因素。列车速度的提高,促使接触疲劳裂纹更易萌生和扩展。而铁路运量和轴重的增加,钢轨磨损日益严重。所以减轻钢轨损伤的已成为迫切需要研究的重要课题。本文通过对现场钢轨的损伤分析和JD-1轮轨模拟试验研究,来研究钢轨的损伤行为和材料选用方式。论文讨论了轮轨滚动接触过程中疲劳和磨损的相互作用关系,分析了钢轨损伤的机理；目的在于为高速和重载铁路钢轨材料的选择提供了理论依据。本文取得的主要结果和结论如下：1、通过对广深铁路现场钢轨的测试分析可知,U75V钢轨具有较高的强度与硬度,但U75V钢轨裂纹扩展消耗能量小,它的裂纹扩展速率要大于U71Mn钢轨裂纹扩展速率,所以U71Mn钢轨抗疲劳裂纹扩展性能优于U75V钢轨,更适合高速铁路铺设使用。2、JD-1轮轨模拟试验表明,车速越高导致钢轨磨损越轻微,塑性流动减弱。但是车速越高,疲劳裂纹扩展越严重。轴重越大钢轨磨损越严重,塑性流动越强,且出现了较深的沟槽。但随着轴重的增加,磨损表面的微裂纹更容易被较大的磨损量所磨去,疲劳损伤轻微。曲率半径越小,钢轨的磨损量越大,塑性流动增越强,且表面容易出现掉快。3、模拟实验发现硬度越小的材料,磨损表面的加工硬化程度越强,塑性变形层就越厚。随着材料硬度的增加,疲劳裂纹随之扩展加剧。因为高速钢轨损伤主要以疲劳为主,而U71Mn热轧钢轨有较好的抗疲劳性能,所以U71Mn更适合于高速铁路铺设使用。因为重载钢轨损伤主要以磨损为主,而U75V淬火钢轨有较好的抗磨损性能,所以U75V更适合于重载铁路铺设使用。更多还原

【Abstract】 The railway transportation in China has been developed rapidly during the first decade of the 21st century. With the increase of train speed and axle load, wheel-rail is bearing ever heavier tribological load and its rolling contact fatigue (RCF) and wear become more and more serious. Various damages of wheel-rail have occurred in some railway lines in China.Laboratory research has been carried out to study the occurrence of wear and rolling contact fatigue damage of rail material using JD-1 wheel/rail simulation facility. The interrelationship between fatigue and wearing during the rolling contact of wheel/rail is discussed and the damage mechanism of the rail is analyzed to provide theoretical basis for the selection of rail materials used in high-speed and heavy-load railway. The main achievements and conclusions are as follows:1. The analysis of testing for the rails on Guangzhou-Shenzhen Railway shows that U75V rail has higher intensity and hardness, but the energy consumption of its crack propagation is low. The rate of crack propagation for U75V rail is higher than that of U71Mn rail. Therefore, the performance of antifatigue crack propagation of U71Mn rail is better than that of U75V rail and U71Mn rail is more applicable to the high-speed railway.2. Laboratory research results indicate that with speed increasing, the wear volume of rail is reduced, as well as many oblique cracks initiate and contact fatigue becomes severer.With axle load increasing, the plastic deformation becomes severer, increasing of wear volume and fatigue failure become slight due to removing of micro-cracks partly. The wear volume of rail roller increases rapidly and fatigue failure become severer with the curve radius decreasing. Furthermore, the rail rollers appear the obvious plastic flow.3. For the rail material with a higher hardness, the wear volume is less and plastic deformation layer is thinner after the rolling test. However, its crack propagation is more significant and the fatigue damage is severer with better wear resistance. Meanwhile, for the rail material with a lower hardness, the wear volume is larger and the plastic deformation layer is thicker. In addition, high wear rate reduces the rolling contact fatigue damage by constantly removing surface cracks. The analysis shows that U75V quenched rail with better wear resistance is suitable for heavy haul railway and U71Mn hot rolled rail with better fatigue resistance is more suitable for the high-speed railway.更多还原