Investigation on hot deformation behavior of 00Cr23Ni4N duplex stainless steel under medium–high strain rates

The hot deformation behavior of 00Cr23Ni4N duplex stainless steel under medium–high strain rates (5–50 s− 1) has been analyzed using the Zener–Hollomon parameter and processing maps, which is based on compression tests made at temperatures ranging from 900 to 1150 °C. The results display the significant influence of high strain rate and high temperature on hot deformation behavior of 00Cr23Ni4N duplex stainless steel. A classical hyperbolic sine equation is applied to reveal the relations between the peak stress, strain rate and deformation temperature, in which the activation energy, Q and stress exponent, n are 263.4 kJ/mol and 2.6, respectively. The Zener–Hollomon parameters at low and high temperatures are calculated respectively to reflect the microstructural evolutions. Based on the processing map obtained, an ideal hot working condition for commercial processing is in the temperature range between 1075 and 1150 °C with a strain rate of 10 to 30 s− 1. Under such condition, both ferrite and austenite dynamic re-crystallizations can be obtained and the corresponding Zener–Hollomon parameter is relatively low. Furthermore, the unstable domains are indicated by the processing map.

Research Highlights
► We investigate the hot deformation behavior of 00Cr23Ni4N duplex stainless steel under medium-high strain rates (5–50 s− 1).
► The methods of Z parameter and processing map are used.
► High strain rate and sufficiently high temperature are benefit to hot deformation.
► The dynamic re-crystallization in ferrite is observed at high strain rates.
► The optimun hot working zone of strain rate range of 10–30 s− 1 and temperature range of 1075–1150 °C is proposed for commercial processing.