| With the technology of the high-speed railway developing, the construction of the high-speed railway in our country is carrying on. Compared with the other countries, the construction technique of the high-speed railway in our country is not perfect. So, it is especially important for the development of our country's high-speed railway to analyze the damages of rails of high-speed sections and determine the damage style and failure mechanism. It has been investigated in detail in the paper that the failure mechanism of PD3 and U71Mn rail from the Guangzhou-Shenzhen railway. It has beenanalyzed in detail by means of by means of optical microscopy (OM),hardnesstester, and scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. The experiments of rolling contact fatigue of three kinds of railmaterials have been carried on by using JD-1 rail-wheel tribology simulating machine. The formation mechanism of crack of rail material has been analyzed in detail by means of by means of optical microscopy (OM), hardnesstester, and scanning electron microscopy (SEM). Main conclusions are drawn as follows: 1. When the trains run on the curve rail, the sliding and impact behaviors ofthe wheel/rail system resulted in a mass of the frictional heat energy. Moreover, the repeated cycles of tension and compression stresses between the contact surfaces would result in the initiation of cracks. Most of the cracks would propagate along the direction of plastic flow into the inside of the rail. 2. The plastic deformation of U71Mn is bigger than the PD3's, which had been paved on the Guangzhou-zhengzhen rial line. As well as U71Mn's poor performance on resisting wear, the tiny cracks would be wiped off by the wear of rail, or polished by the rail grinding. So, the U71Mn rail behaves the better resistance to fatigue. On the contrary, the plastic deformation of PD3 is smaller due to its high strength character. Moreover, the angle between the surface of the...
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