NEW AUSTENITIC AND FERRITIC STAINLESS STEELS FOR SEA WATER APPLICATIONS.

Describes the metallurgical characteristics, mechanical properties and corrosion resistance, primarily as they relate to sea water, of two newly developed stainless steels. The first is a ferritic stainless steel referred to as 29 Cr-4 Mo **(**1**) alloy, while the second is austenitic, designated 6X. The significance of these two steels lies in their pitting corrosion resistance which is superior to that of the currently known stainless steels and approaches that of some Ni-base alloys. The only metals or alloys classified as virtually immune to sea water corrosion are titanium, Inconel 625**(**2**) and Hastelloy C**(**3**). The 29 Cr-4 Mo and 6X alloys have lower alloy content and are therefore expected to be more economical than the three alloys mentioned above. Development of new alloys which meet certain engineering requirements previously satisfied only by materials with a higher alloy content has always been a prime objective of research efforts. The mechanical properties and especially the toughness of the 29 Cr-4 Mo alloy receive special emphasis in this study in view of the criticality of this property in high chromium ferritic alloys.