Austenitic-ferritic duplex stainless steels are stainless steels in which austenitic and ferritic structures account for about half of each. In the case of low C content, the Cr content is 18%~28%, and the Ni content is 3%~10%.

Some steels also contain Mo, Cu, Si, Nb, Ti, N and other alloying elements. This type of steel has both the characteristics of austenitic and ferritic stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, significantly improved intergranular corrosion resistance and welding performance, while maintaining iron The 475 ℃ brittleness of the element stainless steel, the high thermal conductivity and the superplasticity.

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.