A new accelerated test method was developed for crevice corrosion presenting the most important of the problems. Regarding the corrosion resistance of stainless steels in sea water. The effects of alloying elements and microstructure on the crevice corrosion sensitivity were investigated by the method. The corrosion resistance and several service results of a newly developed duplex stainless steel 25Cr-7Ni-3Mo, are also reported.