Investigating the performance of rail steels

This study focusses on aiding the understanding of how various material properties affect rolling the contact fatigue (RCF) and wear of rail steels. This will support the future development of RCF prediction models, and in the identification of rail damage mechanisms. Tensile tests were conducted on several rail steel samples and compared to wear, and RCF data available in literature (Burstow, 2009), to try and meet the aim of this research. The findings from this study support the statements that hardness is a good indicator of ultimate tensile strength and that steel samples from the head and foot of rails have quite different yield strengths (max 24% difference). The strongest outcome of this research is data supporting claims that a ratio of the product of young’s modulus squared and percentage elongation to hardness cubed ((E2*Pe)/H3) had a much better correlation (R2=0.98) to wear data than just hardness (R2=0.89). As well as this, new ideas for characterizing Mark Burstow’s whole life rail model have been presented in this study, due to the importance of understanding how material properties impact rolling contact fatigue and wear. It is suggested in this study that the Tγ Threshold and Tγ Balance of a material could be calculated using ultimate tensile strength (UTS) and not hardness, due to findings showing a higher correlation between the number of cycles to RCF initiation and UTS (R2 = 1.0), than with hardness (R2 = 0.975).