Failure Mechanism of Hadfield Steel Crossing

In this paper failed Hadfield (high manganese austenite) steel crossing in railway system was acted as the research object, the microstructure changes in the worn surface layer of the crossing were investigated by using optical microscopy, X-ray diffraction (XRD) and transmission electron microscope (TEM). The micro-properties of the worn surface and subsurface layers of the crossing were tested by means of nanoindenter equipment. In the mean time, the worn failure mechanism of the crossing was discussed. The results indicated that the microstructure in the worn surface of the Hadfield steel crossing changed to nanocrystalline. The nanocrystalline layer improved the wear resistance of the Hadfield steel. The failure of the Hadfield steel crossing included three stages, that was plastic deformation and wear in the first served stage before the passing trough loads of 1∼2×107 tons, wear in the medial stage among the passing trough loads from 1×107 to 9×107 tons, and fatigue spalling in the final served stage after the passing trough loads of 8∼9×107 tons. Accordingly, some new methods were put forward, which leaded to increase the lifetime of the crossing and enhance the safety of the railway system.