Hot Deformation and Dynamic Recrystallization Behaviour of Medium Carbon Steel in Austenite Region

Abstract

The hot deformation behaviour of a 0.47%C (JIS-S45C) steel in the stable austenite region was systematically investigated under various deformation conditions to collect fundamental data on its high-temperature deformation and microstructure evolution. The medium carbon steel showed dynamic recrystallization in a wide range of temperatures (850°C∼1150°C) and strain rates (10-3 s-1∼100 s-1) in the stable austenite region. The dynamically recrystallized grain size was monotonically decreasing with increasing steady state stress. The minimum grain size obtained through dynamic recrystallization was 8.3 μm when the S45C specimen was deformed at 850°C and 1 s-1. The stress-strain relationships were formularized based on a phenomenological model. The stress-strain curves estimated by the obtained equation were in good agreement with the experimental results.