Evaluation of Crevice Corrosion Resistance of Duplex and Super Duplex Stainless Steels for Seawater Pumps

Crevice corrosion resistance of duplex and super duplex stainless steels used for seawater pumps was evaluated by comparing the results of immersion tests conducted using actual seawater in the Middle East (Arabian Gulf and Red Sea) and Tokyo Bay with the pitting potential of the stainless steels in artificial seawater.  The crevice corrosion occurrence rate in actual seawater decreased as the pitting resistance equivalent (PRE) of the materials became higher; the crevice corrosion occurrence rate varied depending on the material preparing method (rolled, cast, or aged).  The pitting potential in artificial seawater correlated well with the crevice corrosion occurrence rate.  This fact suggests that the crevice corrosion resistance of the stainless steels may be roughly evaluated by measuring their pitting potential in artificial seawater.