Experimental study of the effects of temperature and humidity on the wear and damage behavior of U71Mn rail steel

Wheel-rail interfaces operating in open systems are constantly affected by environmental factors, such as water, relative humidity, temperature, leaves, and sand. In this study, a twin-disc rolling-sliding friction and wear test device with a controlled environmental chamber was used to conduct experiments to study the influence of high temperature and humidity on the wear and damage behavior of U71Mn rail steel. The results showed that surface oxidation of rails increased with increasing temperature and humidity. The surface oxides and very humid air provided lubrication that could reduce wear. With increasing temperature and humidity, the trend of the friction coefficient of the rail samples was basically consistent with that of the plastic deformation layer. The wear of rail samples first decreased and then increased with increasing humidity. However, with increasing temperature, the wear of the rail samples first increased and then decreased. With increasing temperature and humidity, the crack length on the rail surface gradually increased and extended to the center of the material, which made the competition between wear and rolling contact fatigue more intense. When the wear was less than rolling fatigue, rail surfaces underwent severe cracking and peeling, which resulted in the loss of a large amount of surface material.