Strengthening Mechanisms of Rail Metal during Continuous Operation

A quantitative comparative analysis of the strengthening mechanisms for the surface layers of rails is carried out. It is based on the regularities in forming structure, phase composition, defective substructure, and properties of differentially hardened 100-m rails at different depths (up to 10 mm) and performed in the rail head along the central axis and along the symmetry axis of the fillet in the initial state and after various periods of extreme operation (with the handled tonnage of 691.8 and 1411 million gross tons). These regularities are identified using the methods of modern physical materials science. Contributions to strengthening due to friction of the matrix lattice, intraphase boundaries, dislocation substructure, the presence of carbide particles, internal stress fields, and solid solution strengthening of the pearlite constituent in the steel structure are assessed.