Comparative Study on Dry Sliding Wear Behavior of Various Railroad Steels

Understanding the wear behavior of various railroad steels used in different components such as rails, wheels, crossings, and curves has a direct impact on the performance of the rail-wheel system in railroad technology. In the present investigation, the wear behavior of steels having varying microstructures (pearlite, ferrite-pearlite, austenite, and bainite) and different chemical compositions has been studied, utilizing a ball-on-disk sliding tribometer under prototypic load and dry conditions. Results indicate that the wear performance of the steel and the mechanism responsible for its wear are significantly governed by the microstructure as well as changes that occur in the contact region during sliding. The formation of tribo-particles comprising oxides of Fe and their possible smearing resulted in high wear resistance in pearlitic steels with considerable plastic deformation of ferrite lamellae compared with austenitic and bainitic steels. In the case of bainitic steel, the absence of any significant smearing of oxide debris, combined with the presence of some distributed tungsten from the ball, contributed to severe wear. On the other hand, in the case of austenitic steel, third-body abrasion by debris particles, comprising a mix of hard metallic and oxide particles, contributed to severe wear despite its high work-hardening ability. On the whole, the pearlitic steel exhibited superior wear resistance with a lower friction coefficient compared with the bainitic and austenitic steels.