Abstract
The rail/wheel rolling contact affects the microstructure of rail steel in the surface layer of rail. The microstructure was investigated from a point of view of the crystal orientation by means of X-ray inverse pole figure measurement and EBSP analysis. The specific condition that the {111} crystallographic plane of the constituent grains is oriented in parallel to the running surface in the surface layer of a rail used in service for 16 years is confirmed through the analysis of X-ray inverse pole figure and EBSP orientation image map. The degree of orientation evaluated by the axis density of the 111 crystallographic axis varies in the direction of depth from the running surface giving a maximum at about 100 μm from the surface. Based on the results, it is conceivable that the 111 axis density could be a potential parameter to evaluate the degree of rolling contact damage accumulated in the surface layer of used rails.
