Creep Deformation of Type 2205 Duplex Stainless Steel and its Constituent Phases

The creep deformation of type 2205 duplex stainless steel in industrial continuous annealing conditions was analyzed and compared with the creep behavior of its constituent phases, ferrite and austenite. The bulk ferrite phase deformed by viscous glide. The deformation of the bulk austenite phase was by lattice diffusional creep at low applied stress and by dislocation climb at higher applied stress. Grain boundary sliding was the rate controlling mechanism of creep deformation of duplex stainless steel. The value of the stress exponent and the grain size exponent of the creep rate equation both strongly support the possibility that cold rolled type 2205 duplex stainless steel deforms superplastically during recrystallization annealing in industrial continuous annealing furnaces.