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

Research on stainless steels in seawater carried out during the last d ecade is briefly reviewed. With natural seawater it is shown that the formation of a biofilm on the surface has an important influence on th e local corrosion initiation tendency and propagation rate at temperat ures up to 30-40-degrees-C. In chlorinated seawater the tendency to lo cal corrosion initiation is even stronger, but the propagation rate is typically less than in natural seawater. Ageing of the surface is sho wn to have a distinct influence on the initiation tendency, and this o bservation may be utilized during the start-up of a chlorinated seawat er handling system in order to minimize the risk of local corrosion. F inally, testing methods for corrosion in welds and crevices are briefl y discussed and some typical results from such testing are shown. The critical corrosion initiation temperature and a lower critical repassi vation temperature for crevices are dealt with.