Investigation on Hot Compression Precipitation and Recrystallization Behavior of 23.7Cr–2.2Ni–1.3Mo–14Mn–0.26N High‐Manganese Low‐Nickel Duplex Stainless Steel

Abstract

Isothermal compression deformation studies for 23.7Cr–2.2Ni–1.3Mo–14Mn–0.26 N low‐nickel duplex stainless steel (DSS) are investigated under deformation conditions of 800–1150 °C/0.01–10 s−1. The flow curve and deformation microstructure analysis show that deformation softening changes from ferrite dynamic recrystallization (DRX) to austenite DRX, with increasing temperature from 800 and 900 °C to 1050 °C deformed at 0.01–1 s−1. The sigma (σ) precipitate formation is mainly affected by the interaction of deformation temperature and strain rate. In addition to deformation time controlled by strain rate, the refining microstructure of ferrite DRX accelerates σ precipitate formation due to the increase in diffusion channels deformed at 900 °C/0.01 s−1 and 900 °C/1 s−1. The hot deformation activation energy is calculated as 367.03 kJ mol−1, and the relationship between the critical conditions for DRX initiating and Zener–Hollomon parameters is established. The decreasing Z value contributes to deformation softening at low strain, and the DRX softening effect is enhanced deformed at 800–900 °C/0.01–0.1 s−1. Meanwhile, the modified dynamic crystallization kinetics model of tested DSS at a strain rate of 1 s−1 is established.