The effect of white etching layer patches on a larger rail defect

Abstract

Manufacturing defects such as porosity that formed in the rail could result in catastrophic failure if it remain in service. In this study, a crack that initiated from a large void was modelled using boundary element model to investigate the effect of white etching layer patches on larger defects in rail. The configuration studied represents a large defect in the rail that was observed from a rail removed from service. These investigation has provided a better understanding of how a crack initiated from a larger defect grows under the effect of white etching layer. The results highlight that a continuous white etching layer region will dominates the growth of the crack compared to a patches white etching layer region for a smaller crack size while patches of white etching layer will accelerates the crack growth for a larger crack size. The crack growth predicted in this study for a small crack size is at least 6 times higher than the wear rate mentioned in the literature and will increase further if the expansion of a transformed layer is considered making it impossible to be removed by natural wear.