Investigation On Matching Tests Of Wheel/U71Mn Rail Materials

As an important traffic tool in modern transportation, railway occupies irreplaceable important position in national economic development. For this reason, the development of railway is currently under unprecedented attention in many countries. However, when the railway around the world is developing towards high-speed and heavy-haul, some key technical issues are emerging and need to be further resolved. Among these issues, the reasonable matching of wheel-rail materials in wheel-rail relationship is the most important and fundamental and has not been given sufficient attention. Especially in recent years, facing the new environment of the development of high-speed and heavy-haul, the problem of the wheel-rail wear and fatigue damage is becoming more serious, which will seriously affect the safety and reliability of trains, increasing the maintenance time and costs, reducing economic and social benefits of rail transportation. Therefore, test research on matching of wheel-rail materials in laboratory condition will be significant to reduce wheel-rail damnification and to make the railway transportation develop faster and better.According to the Hertz contact theory, using MMS-2A computer-controlled friction and wear testing machine, the matching of three fabricated materials ER7, AAR-B and AAR-C on heat-treated U71Mn rail studied in different simulated load condition. Combining with the optical microscopy(OM), Vickers hardness tester(MVK-H21), scanning electron microscopy(SEM) and energy spectrum analyzer(EDX) surface analysis testing equipment, the rolling contact fatigue and wear behavior of different wheel-rail materials matching in dry friction condition has been studied, and the mechanism that wear affects fatigue crack damage during the wheel-rail rolling has been analysised. The main results and conclusions are as follows:1.The tests have demonstrated three kinds of wheel materials have good abrasion resistance, and the more the carbon content of material, the higher the hardness and the smaller the wear volume is under the same load, meantime, the wear volume of rails increased slightly.2. With the increase of the load, the plastic deformation of the simulated wheel-rail become heavier, and they present quite different wear morphology between different wheel-rail hardness ratios.3. Tests have proved that there is a obvious competition interaction between the wheel-rail performance of wear and fatigue damage resistance. While the wear is serious, the fatigue damage is often slight. On the contrary, while the fatigue damage is serious, the wear is relatively slight.