Evaluation of local strength via microstructural quantification in a pearlitic rail steel deformed by simultaneous compression and torsion
Journal article, 2018

Pearlitic steels are commonly used for railway rails because they combine good strength and wear properties. During service, the passage of trains results in large accumulation of shear strains in the surface layer of the rail, sometimes leading to crack initiation. Knowledge of the material properties versus the shear strain in this layer is therefore important for fatigue life predictions. In this study, fully pearlitic R260 rail steel was deformed using a bi-axial torsion-compression machine to reach different shear strains. Microstructural parameters including interlamellar spacing, thickness of ferrite and cementite lamellae and dislocation density in the ferrite lamellae, as well as hardness were quantitatively characterized at different shear strain levels. Based on the microstructural observations and the quantification of the microstructural parameters, the local flow stresses were estimated based on boundary strengthening and dislocation strengthening models. A good agreement was found between the estimated flow stresses and the flow stresses determined from microhardness measurements.

Pearlitic rail steel

Strengthening mechanisms


Dislocation density



Dimitrios Nikas

Chalmers, Industrial and Materials Science, Engineering Materials

X. Zhang

Technical University of Denmark (DTU)

Johan Ahlström

Chalmers, Industrial and Materials Science, Engineering Materials

Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

0921-5093 (ISSN)

Vol. 737 341-347

Subject Categories

Applied Mechanics

Other Materials Engineering

Metallurgy and Metallic Materials



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