Effects of temperature and load on sliding wear between wheel and rail steels

The contact between railway wheels and rails experiences high mechanical stresses, leading to surface defects that compromise performance, reliability, and safety. Pin-on-disk tests, simulating various conditions with different loads (150 N, 300 N, and 600 N) and temperatures (25 °C and 300 °C), revealed an average friction coefficient of 0.6 at25°C and 0.3 at 300°C. Wear rates for disks were 1.4 × 10^-1 mm³/m at 25 °C and 2.6 × 10^-2 mm³/m at 300 °C, while for pins, they were 2.2 × 10^-2 mm³/m and 3.3 × 10^-3 mm³/m, respectively. For the surface and cross-sectional characterization of the disk samples, macrography, 3D profilometry, scanning electron microscopy, and optical microscopy were used, allowing for the analysis of the worn surface and the characteristics of the tribologically transformed layer. Wear at 25 °C was mostly plastic, while oxidative wear prevailed at 300 °C. High temperatures led to solid lubricating oxides, reducing friction and wear rates, while high loads caused seizure.