ABSTRACT
Two Pan-European programmes including seasonal exposure periods up to six months, have been carried out in the North Sea, Baltic Sea, English Channel, Atlantic Ocean and Mediterranean Sea. All the results showed good behaviour of high alloyed European stainless steels in natural sea water at ambient temperatures. Crevice corrosion phenomena were observed on UNS 31600 and UNS 08904 in some sea water stations. These results, together with electrochemical measurements, suggest that sea water salinity between 4.8%o and 37.7%o is not the relevant parameter for crevice corrosion, while the major parameter is found to be the sea water temperature, particularly at the beginning of the exposure time. Biofilm settlement seems to stimulate crevice corrosion, especially when rapid increase of the corrosion potential occurs at the beginning of exposure, while ageing seems to have a beneficial effect.
