2D and 3D characterization of rolling contact fatigue cracks in manganese steel wing rails from a crossing

• Published in: Wear 2019-10, Vol.436-437, p.202959, Article 202959
• Main Authors: Dhar, S., Danielsen, H.K., Fæster, S., Rasmussen, C.J., Juul Jensen, D.
• Format: Article
• Language: English
• Subjects: 2D & 3D crack network; 3D X-Ray tomography; Contact stresses; Crack propagation; Deformation; Dislocation density; Fatigue cracks; Fatigue failure; Fracture mechanics; Manganese steel; Manganese steels; Metal fatigue; Microstructure; Plastic deformation; Rails; Rolling contact; Rolling contact fatigue (RCF); Structural steels; Switches; Switches and crossings (S&Cs)
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2019.202959

Rail wheel contact at switches and crossings (S&Cs) induces impact stresses along with rolling contact stresses, resulting in plastic deformation and eventually crack formation. Damaged and deformed wing rails of a manganese steel crossing are studied and the microstructure, hardness and 3D crack network within the steel are characterized. It is found that the surface of the rail receives the maximum deformation resulting in a hardened top layer. The deformation is manifested by a high density of twins and dislocation boundaries in the microstructure. A complex crack network is revealed in high resolution by X-ray tomography. •For Manganese steel, damage in the wing rail is similar to that in the nose rail.•The depth of work hardening reaches a depth of 10 mm and 600Hv at the surface.•It can be assumed the impact from the wheel causes the crack formation.•3D mapping of the crack network reveal presence of surface and sub-surface cracks.•The crack network appears similar to that of normal straight track pearlitic steel.