Duplex Stainless Steels: Grades, Properties, and Applications

Duplex stainless steels are a unique class of alloys that offer exceptional strength and corrosion resistance, making them highly suitable for a range of industrial and commercial applications. Their unique properties, which arise from a combination of ferrite and austenite phases, provide an excellent balance of mechanical strength and ductility, making duplex steels suitable for various manufacturing processes. This article explores the different grades of duplex stainless steels, their key properties, and the various applications where they are used.

Grades, Properties, and Applications of Duplex Stainless Steels:

14Cr18Ni11Si4AlTi

Due to the presence of Si, the strength is improved by the two-phase strengthening of α+β, and the surface oxide silicon film is formed in concentrated nitric acid and fuming nitric acid, thereby improving the corrosion resistance to concentrated nitric acid. It is used for making parts and equipment that withstand high-temperature concentrated nitric acid media.

022Cr19Ni5Mo3Si2N (S31500)

It has good resistance to stress corrosion cracking and its resistance to pitting corrosion is similar to that of 00Cr17Ni14Mo2 (316L stainless steel). It has higher strength and is suitable for environments containing chloride ions. It is used in the petroleum, chemical, and other industries for making heat exchangers and condensers.

12Cr21Ni5Ti

It can replace 06Cr18Ni11Ti (321 stainless steel) with better mechanical properties, especially higher strength. It is used in aerospace equipment and other applications.

022Cr22Ni5Mo3N (S31803)

It has high strength, good resistance to stress corrosion, pitting corrosion, and good welding properties. It has a wide range of applications in the fields of petrochemicals, shipbuilding, paper making, seawater desalination, nuclear power, and other industries.

022Cr23Ni5Mo3N (S32205, 2205)

It belongs to low alloy duplex stainless steel with high strength. It can replace S30403 and S31603 and is suitable for use in boilers and pressure vessels, as well as pipelines in chemical plants and refineries.

022Cr23Ni4MoCuN (S32304, 2304)

It has a duplex structure, excellent resistance to stress corrosion cracking and other forms of corrosion resistance, as well as good weldability. It is mainly used in the petroleum and petrochemical industries, paper making, seawater desalination, and other industries.

022Cr25Ni6Mo2N (S31200)

It has significantly better corrosion fatigue resistance than S31603 (urea grade), making it an important reference material for selecting the materials of urea formaldehyde pump bodies that operate under low stress and low frequency cyclic load conditions. It is mainly used in the fields of chemicals, fertilizers, and petrochemicals, and is often used to make heat exchangers and evaporators. It is also widely used in China for urea facilities and other corrosion-resistant parts.

03Cr25Ni6Mo3Cu2N (S32550, 255)

This steel has excellent mechanical properties and resistance to local corrosion, especially wear corrosion resistance, which is superior to that of general stainless steels. It is an ideal material for use in seawater environments and is suitable for applications such as ship propellers, shafts, and submarine seals. It is also widely used in the chemical, petroleum, gas, pulp, and paper industries.

022Cr25Ni7Mo4N (S32750, 2507)

It is the best steel in duplex stainless steels for local corrosion resistance, especially spot corrosion resistance. It also has high strength, chloride stress corrosion resistance, and weldability. It is well-suited for heat exchange equipment in the chemical, petroleum, and power industries where water, groundwater, and seawater are used as cooling media.

022Cr25Ni7Mo4WCuN (S32760)

By adding W and Cu to the 022Cr25Ni7Mo3N steel, the performance of the Cr25 duplex steel is improved. In particular, its resistance to chloride pitting and crevice corrosion is better, making it suitable for heat exchange equipment with water (including seawater and brine) as the medium.

022Cr21Ni3MoN (S32003)

With 1.5% Mo content, the corrosion resistance is improved by combining Cr and N, making it more corrosion-resistant than 022Cr17Ni12Mo2 (316L stainless steel) and similar to 022Cr19Ni13Mo3 (317L stainless steel). It is an ideal replacement for 022Cr17Ni12Mo2 (316L stainless steel). At the same time, this steel also has high strength, making it suitable for applications in chemical storage tanks, pulp paper making, building roofs, bridges, and other fields.

03Cr22Mn5Ni2MoCuN (S32101)

With low Ni and high N content, it has high strength, good corrosion resistance, and weldability, while significantly reducing manufacturing costs. This steel has better corrosion resistance than 022Cr19Ni10 (304L stainless steel) and similar to that of 022Cr17Ni12Mo2 (316L stainless steel). It is an ideal replacement for 06Cr19Ni10 (304 stainless steel) and 022Cr19Ni10 (304L stainless steel), and is widely used in the fields of petrochemicals, shipbuilding, paper making, nuclear power, seawater desalination, and construction.

022Cr21Mn5Ni2N (S32001)

The Ni and Mo content in the alloy is significantly reduced, and it contains a higher N content, which provides high strength, good corrosion resistance, weldability, and lower costs. This steel has corrosion resistance similar to that of 022Cr19Ni10 (304L stainless steel) and can be used as a replacement for 06Cr19Ni10 (304 stainless steel) and 022Cr19Ni10 (304L stainless steel) in applications such as construction, transportation, and petrochemicals.

022Cr21Mn3Ni3Mo2N (S81921)

With 1% to 2% Mo and higher N content, it has good corrosion resistance, weldability, and is cost-effective due to the replacement of Mn and N for Ni. This steel has corrosion resistance similar to or better than that of 022Cr17Ni12Mo2 (316L stainless steel), with significantly improved stress corrosion resistance. It is an ideal replacement for 022Cr17Ni12Mo2 (316L stainless steel) and is used in construction, storage tanks, paper making, petrochemicals, and other fields.

022Cr22Mn3Ni2MoN (S82011)

With higher Cr and N content, this material has better resistance to pitting corrosion and uniform corrosion than 022Cr19Ni10 (304L stainless steel), which is comparable to 022Cr17Ni12Mo2 (316L stainless steel). It also has significantly improved stress corrosion resistance and good weldability. It can replace 022Cr19Ni10 (304L stainless steel) and 022Cr17Ni12Mo2 (316L stainless steel) and is used in construction, storage tanks, petrochemicals, energy, and other fields.

022Cr23Ni2N (S32202)

With higher N replacing Ni and lower Mo content, the cost is significantly reduced. Due to the approximately 23% Cr and approximately 0.2% N content, the material has corrosion resistance similar to or even higher than that of 022Cr17Ni12Mo2 (316L stainless steel). It has significantly improved stress corrosion resistance and excellent weldability, making it an ideal replacement for 022Cr17Ni12Mo2 (316L stainless steel) and suitable for applications in construction, storage tanks, and petrochemicals.

022Cr24Ni4Mn3Mo2CuN (S82441)

With higher N and Mn replacing Ni and lower Cr content, the cost is reduced. With approximately 24% Cr and approximately 0.25% N, the material has higher corrosion resistance to pitting and uniform corrosion than 022Cr17Ni12Mo2 (316L stainless steel) and is similar to that of 022Cr19Ni13Mo3 (317L stainless steel). It has significantly improved stress corrosion resistance and excellent weldability, making it an ideal replacement for both 022Cr17Ni12Mo2 (316L stainless steel) and 022Cr19Ni13Mo3 (317L stainless steel) and suitable for applications in petrochemicals, paper making, construction, storage tanks, and other fields.

Conclusion

Thank you for reading our article and we hope it can help you to have a better understanding of the grades, properties, and applications of duplex stainless steels. If you want to learn more about duplex stainless steels, we would advise you to visit Sino Stainless Steel for more information.

As a leading supplier of stainless steel products across the world, Sino Stainless Steel provides customers with high-quality duplex stainless steels, stainless steel strips, stainless steel coils, stainless steel plates, stainless steel sheets, stainless steel bars, and stainless steel tubes at a very competitive price.