Abstract Scope |
Low-cycle fatigue characteristics of complex phase steel CP800 was investigated at constant strain amplitudes from ±0.2% to ±1.0% after different amount uniaxial tensile prestraining (0%, 2%, 4%, 6%) with or without baking at 170℃ for 20min. Fatigue curves of different states were fitted by Coffin-Manson and Basquin equation. The phenomenon of firstly cyclic hardening and subsequently cyclic softening was presented in the whole fatigue process. The microstructure and fatigue fracture morphology of speimens were observed by SEM and the evolution of dislocation density was analyzed by XRD technique via Williamson-Hall method. Work hardening and bake hardening produced by pretreatment enhance the deformation resistance at the beginning, provide better fatigue performance to the material, and specimens prestraining to 2% emerge the best low-cycle fatigue performance. |