Abstract:A series of hot compression tests were conducted on the new heat-resistant alloy SP2215 for supercritical and ultra-supercritical power plant superheater/reheater tubes using a Gleeble 3500 thermal simulation testing machine at 1100–1250 ℃ and the deformation rate of 0.01–10 s–1 with a deformation amount of 50%. The influence of deformation temperatures and deformation rates on the rheological curve and deformation structure of the alloy was investigated. Furthermore, by modifying the rheological curve based on friction and temperature effects, we established thermal deformation Arrhenius constitutive model, Avrami dynamic recrystallization model, and Yada dynamic recrystallization average grain size model for SP2215 alloy. Additionally, Prasad-Murty-Malas hot working maps were constructed for alloys based on various rheological instability criteria. The results indicate that as the deformation temperature increases, the degree of work hardening decreases while dynamic recrystallization becomes more obvious in SP2215 alloy. Moreover, higher strain rates result in increased flow stress and work hardening rate for this alloy. The recrystallization of the lowest degree occurs at a strain rate of 1 s–1; however, without certain conditions, mixed crystal phenomenon may occur easily in this alloy. Under experimental conditions in this research, the optimal thermal deformation window for SP2215 alloy is the temperature of 1200–1250 ℃ and the strain rate of 5–10 s–1.