Abstract: High-temperature tensile tests were conducted on 17Cr-2Ni-2Mo-0.2N-xMn (x=2, 3, 4) duplex stainless steel at 900-1300 ℃ and 1 s^-1, and thermal compression tests were conducted with 50%, 60%, and 70% deformation at 900-1300 ℃ and 1 s^-1, respectively, to investigate the effect of Mn content on its high-temperature mechanical properties. The results indicate that at a deformation temperature of 900 ℃, ferrite undergoes dynamic recrystallization, while austenite only undergoes partial dynamic recrystallization. At a deformation temperature of 1200 ℃, ferrite mainly undergoes dynamic recovery, while austenite undergoes dynamic recrystallization. All specimens exhibit varying degrees of dynamic recovery or dynamic recrystallization during high-temperature deformation, with secondary hardening occurring in the final stage of the thermal compression test. In the thermal compression test, when the Mn content increases from 2% to 4%, the dynamic recrystallization behavior of 17Cr duplex stainless steel first intensifies and then slows down in the temperature range of 900-1100 ℃. However, at deformation temperatures of 1200 ℃ and higher, the effect of Mn content on the dynamic recrystallization behavior is relatively small. At the temperature range of 1150-1200 ℃, the thermal tensile deformation resistance decreases initially and then increases with the rise of manganese content, with 3% manganese providing the best hot working performance.

Key words: lean duplex stainless steel, Mn, thermal deformation, dynamic recrystallization, strain hardening rate