Hot Compression Behavior of 18Cr–11Mn–0.06Ni–0.19N High‐Mn Ultralow Nickel Duplex Stainless Steel under Large Deformation

Abstract

To enhance the rolling production efficiency of high‐manganese low‐nickel duplex stainless steel (DSS) and optimize hot compression parameters, hot compression with a range of 0.01–10 s−1/850–1150 °C and deformations of 70% is used to investigate the hot deformation behavior of 18Cr–11Mn–0.06Ni–0.19 N DSS, which reveals the differences in the recrystallization mechanism of two phases and their thermoplastic properties. The results show that strain partitioning and softening occur first in the ferrite phase, with the austenite phase undergoing complex and incomplete softening. Most ferrite experiences continuous dynamic recrystallization and develops a <001>//ND texture when deformed at 0.1–10 s−1/950 °C, with higher temperatures facilitating the merging of high‐angle grain boundaries. A deformation‐induced phase transformation from δ to γ occurs in ferrite when deformed at 0.01 s−1/850–950 °C. However, austenite softening is dominated by discontinuous dynamic recrystallization, enhanced by twinning‐induced strain‐induced boundary migration when deformed at 0.1 s−1/950 °C; dynamic recovery controlled by dislocations is enhanced when deformed at 0.1 s−1/1150°C and 10 s−1/950 °C. A strain‐compensated constitutive model with an average absolute relative error value of 7.8% is established to better predict the flow stresses. Experimental DSS displays optimal hot workability in the parameter ranges of 0.1 s−1/950–1050 °C.