Characterization of the compression properties of rail steels at high temperatures and strain rates

Abstract

This paper describes a study of the mechanical behaviour of several rail steels at elevated temperatures and strain rates exceeding 10 3 s −1. Dynamic compression testing was performed at high strain rates on several plain carbon and low alloy eutectoid rail steels in the temperature range 25–680 °C using a modified version of the direct impact Hopkinson bar to generate adiabatic stress-strain curves. It was found that the flow stress dependences on the initial testing temperature and interlamellar spacing of pearlite at high strain rates and 25 °C follow the same established trends reported for the low strain rate regime. Impacts at low deformation temperatures (25–180 °C) were found to induce localized catastrophic shearing at the strain rate tested in steels with a fine pearlitic structure.