Effects of rail materials and axle loads on the wear behavior of wheel/rail steels

Abstract

Four kinds of rail steels were tested to investigate the wear behaviors of wheel-rail materials under three kinds of axle loads. Results indicate that the increase in axle load not only significantly enlarges the wear loss but also enlarges the depth and the length of the fatigue cracks. However, with the decreases in the hardness ratios, some ripples are exhibited on the surface, and the wear surfaces become much rougher; the subsurface analyses deliver the presence of extremely rough surface, and the deformation depths are irregular. The relationship between the total wear loss of the wheel/rail system and the hardness ratio indicates that the hardness ratio of wheel/rail steels has slight impact on the total wear loss at a low axle load; however, the decrease in the hardness ratio enlarges the total wear loss significantly at a high axle load. In summary, a quenched rail should be chosen for the heavy-haul railway, and the hardness of the wheel steel should be raised to a degree close to the rail. However, a hot rolled rail is much suitable for the high-speed railway, and the wheel hardness should be smaller than the rail.

Dry Rolling/Sliding Wear of Bainitic Rail Steels under Different Contact Stresses and Slip Ratios

“…Therefore, besides the influence of the contact pressure, rolling velocity and slip ratio, the friction coefficient could also be affected by the microstructural properties of materials. In the present study, it is proved that the bainitic steel behaves a lower friction coefficient at the large axle load, which may be opposite with the results in pearlitic steels [ 37 ]. The influence of microstructural features, such as work hardening behavior, surface roughness or elastic-plastic deformation behaviors, on the friction coefficient should be deeply studied in the future work.…”

“…Comparison with the wear behaviors of pearlite rail steels in paper [ 37 ], the authors found that the increases in axle loads enlarged the friction coefficient significantly, and the values were about 0.36, 0.42, and 0.53 for the axle loads of 16, 21, and 25 t, respectively. However, based on the research of Chen et al [ 38 ], the influence of the axle load on the adhesion of wheel and rail was not proportional, but the adhesion depended on the surface roughness and the running speed of a vehicle.…”

Modeling of braking thermal effect for wheel-rail contact parameters

“…Load, contact pressure and shear stress for solo thermal loading as well as for equivalent mechanical load for different temperatures of wheel due to braking can be obtained using equations (15). The values obtained by these equations and by FEA are in good agreement.…”

“…Properties of CL60-wheel, U71Mn50-rail materials. 14,15 Modulus of elasticity (GPa): corresponding dimensions of contact patch, deformation and contact stresses at the interface. Figure 6 shows the contact patch at the interface due to combined thermal and mechanical loading.…”

Research of the Defective Frog Wing of 1/11 Mark

“…8). To determine the chemical composition of the metal, an ARC-MET 8000 Mobile Lab optical emission analyzer was used [12]. Measurements were made at three different points, three times, at the top, in the web and at the base of the wing.…”