Duplex stainless steels: requirements, challenges, and solutions

The article addresses the key challenges faced by developers, manufacturers, and consumers of cast austenitic-ferritic (duplex) steel products for the oil, gas, and petrochemical industries. It examines the main issues associated with the increased content of alloying elements, which lead to a higher risk of unfavorable secondary phase formation, as well as complications in the production process and in controlling steel purity from harmful impurities. It is shown that existing standards impose varying requirements on chemical composition, macro- and microstructure, as well as mechanical and corrosion properties, making it difficult to ensure the quality control of cast duplex stainless steels (DSSs). The paper discusses the lack of domestic standards and provides solutions implemented by Russian enterprises. Real examples of cast DSSs quality optimization from the authors’ experience are also presented.