Fig. 1 Complete experimental procedures for hot deformation of SIMP steel

Fig.2 True stress-strain curves of the SIMP steel deformed at 900 °C a, 1000 °C b, 1050 °C c, 1100 °C d, 1200 °C e

Fig.3 Microstructures of SIMP steel deformed at a 900 °C, 0.1 s-1, b 1000 °C, 0.1 s-1, c 1100 °C, 0.1 s-1, d 1200 °C, 0.1 s-1, e 900 °C, 10 s-1, f 1000 °C, 10 s-1, g 1100 °C, 10 s-1, h 1200 °C, 10 s-1

Fig. 4 Strain hardening rate plots for SIMP steel (σc: critical stress)

Fig. 5 Flow stress dependence of $- \partial \theta /\partial \sigma$ for SIMP steel (The inset shows the minimum point of the second numerical derivative of flow curves as a function of stress at the inflection point of work hardening curve. This unique minimum point gives a good estimate of the critical stress)

Fig. 6 Plots of $\ln \dot{\varepsilon } - \ln \sigma_{\text{c}}$ and $\ln \dot{\varepsilon } - \ln [\sinh (\alpha \sigma_{\text{c}} )] $for calculation of hot working constants for SIMP steel

Fig. 7 Linear relationship of ln[sinh(ασc)] versus (1/nRT)

Fig. 8 Linear relationship of ln[sinh(ασp)] versus (1/nRT)

Fig. 9 Curves of lnεc and lnεp versus lnZ

Fig. 10 Curves of lnσc and lnσp versus lnZ

Fig. 11 Instability and processing maps in strain range of 0.1-0.9 for SIMP steel