Probing the Effect of Grinding Stone Strength on Rail Grinding Behavior

The strength of the grinding stone (GS) has a significant effect on the sustainable operational capacity and grinding efficiency of grinding car, thus probing the effect of grinding stone strength on grinding behavior and rail surface quality will be beneficial for the selection of grinding stone on the field. According to the compressive strength of the Vossloh GS used on the field, three GSs (GS-10, 68.9 MPa; GS-12.5, 95.2 MPa and GS-15, 122.7 MPa) were prepared to carry out grinding experiments, and the corresponding characterizations were applied to analyze the surface morphologies of GSs and ground rails. The results showed that the GS-15 had a decrease of 80% on grinding volume but an increase of 88% on grinding ratio comparing with the GS-10. The results indicated that the improvement of GS strength produced a promotion of wear resistance and a reduction of grinding ability. The surface morphologies of GSs and rail samples showed that the improvement of GS strength resulted in a worse self-sharpening which caused the main grinding mechanism changing from cutting to ploughing. The results of SEM, EDS and XPS of the ground rail surface indicated that the cutting process had influences the production of grinding heat most, and the increase compressive strength of GS caused an improvement of Fe²⁺, a reduction of Fe³⁺, and a lower burning degree. However, the metallographic results viewing from the cross sections of ground rails showed that the thickness of the white etching layer and plastic deformation layer grew with the increase of the GSs’ compressive strength, causing a more severe pre-fatigue of rail. Therefore, the reasonable regulation of the strength of GS was of great significance to the improvement of grinding efficiency and rail surface quality.