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What Is Duplex Stainless Steel?
Time: 2023-12-21
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Duplex stainless steel is a stainless steel that contains a two-phase microstructure consisting of an austenite (or face-centered cubic) phase and a ferrite (or body-centered cubic) phase. This unique phase combination gives duplex stainless steel a range of advantages, making it a popular choice for a variety of applications in industries such as oil and gas, chemical processing and offshore engineering. This blog post will take you through what duplex stainless steel is and its characteristics, physical properties, uses, etc.

What is Duplex Stainless Steel?

Duplex stainless steel (DSS for short) refers to stainless steel in which ferrite and austenite each account for about 50%. Generally, the content of the smaller phase must be at least 30%. In the case of low C content, the Cr content is 18%~28% and the 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 steels.

Compared to ferritic, it has higher plasticity and toughness, no brittleness at room temperature, and significantly improved intergranular corrosion resistance and weldability. At the same time, it retains the 475°C brittleness and high thermal conductivity of ferritic stainless steel and has superplasticity. Features.

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

Physical Property:

  • Thermal expansion coefficient: The thermal expansion coefficient of this stainless steel is lower than austenitic stainless steel in most applications.
  • Density: Its density is slightly lower than austenitic stainless steel.
  • Resistivity: This stainless steel has a higher resistivity than austenitic stainless steel.
  • Thermal conductivity: Its thermal conductivity is slightly higher than austenitic stainless steel.
  • Magnetism: This stainless steel is magnetic.

In addition, duplex stainless steel 2205 is a composite stainless steel composed of 22% chromium, 2.5% molybdenum and 4.5% nickel-nitrogen alloy. It not only has high strength, but also has good impact toughness and good overall and local stress corrosion resistance.


This stainless steel has been widely used in various industrial fields, such as pulp and paper, onshore and offshore oil and gas industry, chemical processing industry, transport industry (chemical ships and tankers), pharmaceutical and food industry, and construction industry. It is usually used as a reaction vessel, a variety of industrial equipment and transport pipelines.

In addition, duplex stainless steel is also commonly used in the manufacture of heat exchangers, condensers and other equipment.

Quanshuo Metal Materials is a manufacturer that has passed ISO9001:2015, TUV, SGS, and CE certification. It mainly produces Stainless Steel, etc., with an annual output of 300,000 tons. Looking forward to your inquiry.

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