Effect of temperature on deformation and fracture behaviour of high strength rail steel

• Temperature-dependence of KIc on entire cross section of high strength rail steel.
• True stress–strain curve of rail steel under uniform and non-uniform deformation.
• Experimental and numerical study of temperature effect on Vickers indentation tests.

Fracture toughness (KIc), Vickers hardness, and constitutive equation under tensile loading for high strength rail steel were determined at −40, −10 and 23 °C. KIc and hardness were directly determined from experimental testing, while the constitutive equation also relying on finite element (FE) modelling because of the non-uniform deformation during the necking process. The constitutive equation was verified by enabling the FE model of tensile specimen to regenerate the experimentally measured load–elongation curve and cross-section reduction, and applied to the FE model of Vickers indentation to mimic the load–depth relationship. This paper also discusses relevance of the results with those reported in literature.