Duplex Stainless Steel (DSS) refers to ferrite and austenite each accounting for about 50%, generally less phase content at least 30% stainless steel. In the case of low C content, Cr content is 18%~28%, Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N.

This type of steel has the characteristics of both austenitic and ferritic stainless steel, compared with ferritic, plasticity, toughness, no room temperature brittleness, intergranular corrosion resistance and welding performance are significantly improved, while maintaining the 475 °C brittleness and high thermal conductivity of ferritic stainless steel, with superplasticity and other characteristics. Compared with austenitic stainless steels, it has high strength and resistance to intergranular corrosion and chloride stress corrosion is significantly improved. Duplex stainless steel has excellent pore resistance and is also a nickel-saving stainless steel.