Gradients of Structure, Phase Composition, and Dislocation Substructure of Rails under the Ultra Long-Term Operation

In this paper, the structure, phase composition, dislocation substructure, and carbon redistribution in differentially quenched 100-meter rails after ultra long-term operation (passed gross tonnage since 2013 — 1770 mln. tons) are studied using modern materials science engineering approaches. The regularities of main parameters variations, such as changes a relative variety different morphological structures, scalar excessive density, volume fractions cementite, atoms, identified at rail head cross section along central axis fillet rounding radius distances 0, 2, 10 mm from surface. It is suggested that decrease fraction carbide surface layer can be related to decarburization appearance atoms steel structure defects. noted transformations proceed slower relation fillet.