The diagnostics and ways heat treatment optimization of a railway wheels steel

Abstract

A high resolution sensor of linear displacements has been elaborated for diagnosing the size of the crack tip opening in standard test specimens. Based on the data measured during fatigue crack growth resistance tests of a wheel steel heat treated after various modes, calculations of the strain and energy parameters of local fracture were performed for the corresponding variants of treatment, and fatigue crack growth rate diagrams were constructed using different approaches of fatigue fracture mechanics. It was established that the diagrams obtained using the strain and energy approaches are more sensitive to material microstructure and its mechanical properties than the traditional diagrams obtained using the stress approach. Based on the parameters of the fatigue crack growth resistance estimated using the strain and energy approaches, the effective diagnostics and the best heat treatment mode for the wheel steel was developed. It comprises the stages of isothermal quenching and tempering at a temperature of 500 °С, providing the highest fatigue fracture toughness of the steel.

Endurance limit of the axial-piston hydraulic machine cylinder block

“…Stresses that arise in unevenly loaded details of complex shape are often localized in small internal volumes and it is only experimentally possible to effectively determine their effect on strength and fatigue resistance. Such works were carried out for local sections of notched samples of material [7], individual structure units [8,9] and vehicles [10,11] and even for multi-storey buildings [12] on special stands. Making stands and performing experiments are requires considerable expenditure of resources and time, therefore, in modern conditions, the analysis of strength and fatigue resistance is carried out numerically more often.…”

Assessment of durability and reliability of ET41 series locomotive wheels based on laboratory tests

“…The factors that determine how competitive the railways are depend on transport time, costs, and comfort. They, in turn, depend directly on the technical condition of railroad wheels and rails [17,24].…”

“…There are also works conducted aimed at increasing the resistance of steel to wear and rolling contact fatigue of tracks, e.g. through the selection of material or heat treatment [3,24,28,29]. What also affects wheel and track wear is the design of the suspension system of bogie trucks.…”