The crevice corrosion performance of 445M ferrite stainless steel ( % ： 0. 004 ~0. 005C

22. 4 - 22. 29Cr

1. 10 ~ 1. 65Mo

0. 015 ~0. 016P

0. 003 ~0. 004S

0. 012 -0. 016N

0. 22 - 0. 38Ti) and 316L austenite stainless steel ( % ： 0. 022C

16. 80Cr

10. 19Ni

2. 02Mo

0. 025P

0. 001S

0. 046N) in sodium chloride solution with chlorion concentration (250 - 5 000) x 10

-6

at 40 ~ 60 ℃ has been studied. Results show that the crevice corrosion resistance of 445M steel is better than that of 316L steel ； and with increasing the Mo content in 445M steel from 1. 10% to 1. 65%

the crevice corrosion resistance of steel obviously increases

it indicated that the pitting corrosion resistance equivalent- Cr +3. 3Mo is an important index to measure the pitting and crevice corrosion resistance of stainless steels.