The crystal orientation in the surface layer of a rail was analyzed by means of X-ray inverse pole figure measurement and EBSP analysis for rail used in service on a narrow-gauge line to an accumulated service tonnage of 160 MGT and damaged by repeated rolling contact with wheels of rolling stock. A specific condition that the {111} crystallographic plane of constituent grains is oriented parallel to the running surface in the surface layer of the rail 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 reaching a maximum at about 100 μm from the surface. Based on these results, the 111 axis density is thought to be a potential parameter to evaluate the degree of the rolling contact damage accumulated in the surface layer of rails used in service.

Copyright (c) 2004 Railway Technical Research Institute