Abstract: The tested 00Crl8Nil0N steel (/% ：0. 018C,0.41Si, 1. 68Mn, 18. 18Cr, 10. 38Ni,0. 16N) is melted by 1 t EAF-AOD-ESR process, forged to Φ30 mm bar and solid-solution-treated at 1 050℃ . The axial high-cycle fatigue properties of 00Crl8Nil0N steel with two stress-concentration coefficients (SCs) ( smooth: K_t= 1, notch:K_t=3 ) at 200 ~ 600 ℃. are studied. The fatigue S-N curve is obtained, the fatigue limits of two SCs are calculated and the typical fracture morphologies of fatigue specimens are observed by SEM. The results show that fatigue limits of the smooth specimens decrease with increasing of test temperature, and the fatigue limits of the notch specimens are not sensitive to the change of test temperature. When SCs rises from K _t=1 to K_t = 3, the 10⁷ cycles fatigue limits of 00Crl8Nil0N steel at 200 , 400, and 600 ℃ decreases respectively from 530、506、410 MPa to 323、370、392 MPa. It shows that the 00Crl8Ni10N steel has obvious fatigue limit stress concentration sensitivity at elevated temperatures, and the stress concentration sensitivity decreases with increasing of test temperature. The fracture of the fatigue specimen is composed of three parts： the fatigue source zone, the fatigue crack propagation zone and the instant fracture zone. The fatigue originates from the discontinuous positions of the surface machined tool marks and exhibits a ductile-fracture characteristic.

Key words: Austenitic Stainless Steel 00Crl8Nil0N, Elevated Temperature, , Fatigue Limit, Fatigue Lifetime, Fracture Analysis, Stress Concentration