Microstructure and mechanical properties of the running band in a pearlitic rail steel: Comparison between biaxially deformed steel and field samples

The large deformations occurring in the surface layer of rail heads strongly influence the material behavior. Cracks typically develop from this critical region. However, conventional material testing of this layer is not possible due to the large gradients. A method for obtaining a similar material through predeformation is therefore investigated. Subsequent analyses of the obtained material can improve our understanding of the material behavior close to the running band. Hardness, shear lines and cementite lamella orientation distributions are compared in order to determine whether the obtained material is similar to that of the field samples extracted from rails that have been in service for several years. The predeformation method produces a consistent material, which is representative of the material in the rail field samples that have accumulated large shear strains.