Effect of Fatigue Load on High-Temperature Tensile Properties of P92 Steel

The strain controlled fatigue tests at 650℃ for different cycles, followed by the tensile property tests at 650℃, were conducted on P92 steel. The effects of fatigue load on the high-temperature tensile properties of the steel were investigated. The results show that after fatigue testing for different cycles, the high-temperature tensile properties of P92 steel decreased. When the number of cycles reached 20%N_f (N_f refers to fatigue life), the tensile strength and yield strength decreased by 19.1% and 38.6%, respectively. When the number of cycles was higher than 20%N_f, the tensile strength and yield strength tended to be stable. The tensile fractures of the fatigue tested specimens illustrated ductile fracture characteristics. The dimples on the tensile fracture changed from small and deep to big and shallow when the number of cycles increased from 0 to 20%N_f, while changed little when the number of cycles reached higher than 20%N_f.