Corrosion Resistant Stainless Steels with Microduplex Structure

Abstract

Stainless steels with duplex structure of ferrite and austenite are superior in some properties such as corrosion resistance and mechanical strength to austenitic stainless steels. Composition ranges of them are about 18 to 28% Cr and 2 to 10% Ni. New types of these steels have low carbon content and adjusted chemical composition to keep appropriate phase balance of ferrite and austenite. Some of them contains 1 to 3% Mo, 0.1 to 0.2% N to improve the corrosion resistance to pitting. In this paper, the following subjects of the new duplex stainless steels are mainly described:
(1) Resistance to stress corrosion cracking and pitting corrosion.
(2) Effects of heat treatments on microstructure and other properties.
(3) Examples of application.