What Is Duplex Stainless Steel Pipe

Duplex steel is also called duplex steel. A steel consisting of two phases of martensite or austenite and ferrite matrix. Generally speaking, the steel composed of ferrite and austenite phase structure is called duplex stainless steel, and the steel composed of ferrite and martensite phase structure is called duplex steel. Due to the characteristics of two-phase structure, the duplex stainless steel has the advantages of both ferritic stainless steel and austenitic stainless steel through the correct control of chemical composition and heat treatment process. It combines the excellent toughness and weldability of austenitic stainless steel with the high strength and chloride stress corrosion resistance of ferritic stainless steel, which makes the duplex stainless steel superior Can, as a weldable structural material, develops rapidly.

Duplex stainless steel pipe has good welding performance. Compared with ferritic stainless steel and austenitic stainless steel, it is neither like the HAZ of ferritic stainless steel, because of the grain coarsening, the plastic toughness is greatly reduced, nor like austenitic stainless steel, it is more sensitive to welding hot cracks.

The main characteristic of duplex stainless steel is that its yield strength can reach 400-550mpa, which is twice that of ordinary stainless steel, so it can save materials and reduce equipment manufacturing cost. In the aspect of corrosion resistance, especially in the condition of bad medium environment (such as seawater, high chloride ion content), the pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance and corrosion fatigue performance of duplex stainless steel are obviously superior to that of ordinary austenitic stainless steel, which can be compared with high alloy austenitic stainless steel.

Due to its special advantages, duplex stainless steel pipe is widely used in petrochemical equipment, seawater and wastewater treatment equipment, oil and gas pipelines, papermaking machinery and other industrial fields. In recent years, it has also been used in the field of bridge bearing structure, which has a good development prospect.