Recrystallization Behavior of Deformed Austenite in High Strength Microalloyed Pipeline Steel

Using methods of single-hit hot compression and stress relaxation after deformation on a Gleeble 1500D thermomechanical simulator, the curves of flow stress and stress relaxation, the microstructure and the recrystallization behavior of Nb-V-Ti high strength microalloyed low carbon pipeline steel were studied, and the influence of the thermomechanical treatment parameters on dynamic and static recrystallization of the steel was investigated. It was found that microalloying elements improved the deformation activation energy and produced a retardation of the recrystallization due to the solid solution and precipitation pinning. The deformation conditions such as deformation temperature, strain, and strain rate influenced the recrystallization kinetics and the microstructure respectively. Equations obtained can be used to valuate and predict the dynamic and static recrystallizations.