Metallurgical investigation of transverse defects in worn rails in service

Abstract Transverse defects (TDs) of rails that were installed in heavy-haul railways have been investigated, and Finite Elemental Method (FEM) Analysis were conducted to clarify the mechanism of TD occurrence. From the results of metallurgical investigations and elastoplastic FEM, it is found that the central liner crack (CLC) that is initiation point of TDs occur by the tensile-type normal fatigue, and the initiation point of CLC lies at the elastic-plastic boundary which is located about 56 mm depth beneath the gauge corner, where tensile stress of about 200 MPa works cyclically in the width direction of the rail head in every passing of wheels. As there is no large non-metallic inclusions at the initiation point of the CLC, a possibility of the fatigue fracture at the elastic-plastic boundary has been discussed in connection with metallurgical and mechanical factors in rail head.