THE BEHAVIOR OF CORROSION-RESISTANT STEELS IN SEAWATER - A REVIEW

Research on stainless steels in seawater carried out during the last decade is briefly reviewed. With natural seawater it is shown that the formation of a biofilm on the surface has an important influence on the local corrosion initiation tendency and propagation rate at temperatures up to 30-40-degrees-C. In chlorinated seawater the tendency to local corrosion initiation is even stronger, but the propagation rate is typically less than in natural seawater. Ageing of the surface is shown to have a distinct influence on the initiation tendency, and this observation may be utilized during the start-up of a chlorinated seawater handling system in order to minimize the risk of local corrosion. Finally, testing methods for corrosion in welds and crevices are briefly discussed and some typical results from such testing are shown. The critical corrosion initiation temperature and a lower critical repassivation temperature for crevices are dealt with.