Hot deformation behavior of a Ni-free, Fe-17Cr-12Mn-0.28N-0.06C (wt. %) austenitic stainless steel (ASS), hereinafter coded as FeCrMnN, was investigated using hot compression tests conducted under different deformation conditions comprising temperature ranges of 800 – 1200 °C and strain rates of 0.01 – 10 s -1 , respectively. While the hot deformation at high strain rate and low temperatures (e.g. 10 s -1 and 800 or 900 °C) showed essentially dynamic recovery (DRV), resulting in a pancake shaped microstructure, most of the other conditions exhibited occurrence of dynamic recrystallization (DRX). Increasing deformation temperature and decreasing strain rate showed a decrease in the critical stress and strain for initiating DRX. In general, DRX resulted in extensive microstructural reconstitution and grain refinement. For instance, hot deformation at 1000 °C / 0.01 s -1 resulted in a fully recrystallized fine-grained microstructure with an average grain size of about 15 ?m in comparison to the initial grain size of 60 µm. Increasing temperature enhanced grain growth, but an increase in strain rate resulted in a finer grain structure. The amount of delta ferrite in the present steel was changed under different conditions of deformation such that the lowest amount of delta ferrite was observed at 1000 °C. The activation energy of deformation (Q def ) for the present FeCrMnN steel with the initial grain size of 60 µm was estimated to be about 502 kJ/mole, which is higher than those of the conventional austenitic stainless steels. Keywords: Hot deformation; Nitrogen-bearing Ni-free austenitic stainless steel; Dynamic recrystallization; Activation energy of deformation
