Experimental study on fatigue damage of wheel rail contact surface caused by solid lubricants

Purpose This study aims to explore the role of solid lubricants in reducing material wear and delaying fatigue failure of subway wheel rail, revealing the competitive relationship between macroscopic wear and microscopic damage and providing theoretical support for optimizing wheel rail maintenance strategies. Design/methodology/approach This study is based on an improved GPM-60 friction and wear testing machine, and constructs a simulation test platform for subway wheel rail contact conditions. The effects of three solid lubricants on the surface wear morphology, crack propagation and fatigue damage of the wheel rail were systematically evaluated. Findings Experiments have shown that both MoS2 and graphite based solid lubricants can significantly suppress macroscopic wear. Under lubrication conditions, the average width of wear marks on the wheel rail surface is reduced by 50.0%, 34.2% and 40.8% compared to the control group D, with an overall decrease of 41.67%; However, microscopic analysis shows that the use of lubricants accelerates the initiation and propagation of fatigue cracks in the sub surface layer of the contact surface, indicating a clear competitive mechanism between material loss and fatigue damage. Originality/value By improving the testing machine, synchronous observation of multi-scale damage (macro wear micro fatigue) between wheel and rail was achieved, revealing the dual effect of solid lubricants in reducing wear while exacerbating fatigue damage. This provides a new perspective and methodological basis for the full life cycle management of subway wheel rail and the collaborative design of anti-wear and anti-fatigue for high-wear mechanical components.