Duplex stainless steels have a ferritic-austenitic microstructure with approximately equal proportions of 50% ferrite and 50% austenite.

Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, significantly improved intergranular corrosion resistance and welding performance, and also maintains 475°C brittleness and high thermal conductivity of ferritic stainless steel, with superplasticity and other characteristics.

Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chloride stress corrosion. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.

Duplex stainless steels combine many attractive properties of ferritic and austenitic stainless steels, which allows duplex steels to provide better resistance to corrosion, especially stress corrosion and pitting corrosion. This microstructure provides higher strength than standard austenitic stainless steels such as Type 304 or 316. In recent years, duplex stainless steels have become increasingly popular. Various models are available such as Duplex 2205, Superduplex 2507 or lean duplex steel with a lower nickel content.