Susceptibility of pearlitic rail grades to thermal white etching layer formation

Abstract

One of the most critical issues in railway engineering is the rail lifetime optimization. In track, rails suffer from various degradation forms like the head checks, squats and studs. The white etching layer (WEL) is considered as a primary stage of damage. The WEL usually appears as a metallurgical change due to the severe loading in the rail running band. This work addresses their generation based on the wheel-rail contact together with a metallurgical analysis. Influences of microstructure and stress on the austenite transformation kinetic are simulated. Consequently, the isothermal austenization diagrams for R260Mn, R350HT and R370CrHT grades under stress are discussed. It turns out that the austenitic transformation is possible within a comparable time to the wheel-rail contact duration.