Distribution of tensile properties of high-speed rail wheels and its correlation with microstructure

Abstract The tensile strength of railway wheels is a crucial mechanical property in the quality assessment and safe service of wheels. Conventional tensile testing imposes strict requirements on specimen size and can only test one specimen in each experiment, hindering its application to the characterization of the tensile strength distribution of train wheels with complex structures. In this study, six-channel mechanical testing of miniature specimens was applied to characterize the tensile properties of high-speed rail wheel rims, enabling analysis of the correlations between micro-zone tensile properties and microstructures of high-speed rail wheels. The results showed that micro-zone tensile strength gradually decreased as the depth of the micro-zone increased from the tread surface to the radial interior. Moreover, both micro-zone tensile strength and plastic extension strength also gradually decreased as the pearlite lamellar spacing and ferrite area fraction increased. Micro-zone tensile strength and plastic extension strength showed good correlations with pearlite lamellar spacing and ferrite area fraction, with polynomial best-fit curves presenting correlation coefficients >0.95. The results of this study could serve as a technical reference for studying the tensile properties of high-speed rail wheel steel.