Mechanical properties of metastable austenite in low-alloy steels

Abstract

The mechanical properties of metastable austenite in three low-alloy steels have been examined in the temperature range 500–950°C. In general, behaviour typical of an fcc metal has been found with, for example, the yield strength being less dependent on temperature than the tensile strength. In the Cr–Mo–Ni steel (817 M 40) examined yield points were found on the austenite stress–strain curves after static strain aging. These have been attributed to precipitation taking place during the strain aging. While the flow stress of 817 M 40 metastable austenite was found to be independent of strain rate in the normal ausforming temperature range, the other two steels examined, Fe–5Cr–0·2C and Fe–4Cr–1V–0·2C, were both found to be strain-rate sensitive with dynamic strain aging being evident at low strain rates.