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 o

f the notch specimens are not sensitive to the change of test temperature. When SCs rises from K

t

=1 to K

t

= 3

the 10

7

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.