Duplex S31803 (2205) & Super Duplex S32750 (2507)

Duplex-grade stainless steel alloys have ferritic/austenitic properties, giving these materials superior strength and excellent resistance to oxidation. While the duplex-grade family includes a wide range of specific formulations, duplex S31803 (2205) and super duplex S32750 (2507) stainless steel are two of the most common. These stainless steel products are extremely versatile, with many applications in the oil and gas, petrochemical, and chemical processing industries.

Duplex S31803 and Super Duplex S32750 Performance

Duplex S31803, also known as stainless steel grade 2205, is a standardized formulation that conforms to UNS specification regulations. Its temperature range is typically listed as -50° to 300° C (-58° to 572° F); outside of this range, its performance characteristics degrade. Specifically, duplex S31803's micro-components experience precipitation with prolonged exposure to high temperatures, and ductility suffers with immersion in extremely cold environments.

Its general capabilities include:

  • Excellent oxidation resistance
  • Outstanding performance in marine/sea water environments
  • Low thermal expansion coefficients
  • High heat conductivity

Super duplex S32750 (2507) is a variant stainless steel alloy that is primarily used in the oil and gas industry, particularly for offshore platforms, heat exchangers, structural components, and architectural components. Along with very high tensile and yield strength ratings, super duplex S32750 resists stress corrosion cracking extremely well and is pitting resistant, highly weldable, and very versatile.

If you would like further information on the performance characteristics of duplex-grade stainless steel products, or have other inquiries, please contact a Ram Alloys team member. We offer more than 100 years of combined industry experience, and are available to answer all questions about steel alloys and their condition variants.


Chemical Composition Table

UNS: S31803 

Min           21.0 4.5 0.08 2.5
Max 0.030 2 0.030 0.020 1.00 23.0 6.5 0.20 3.5



UNS: S32750

Min           24.0 6.0 0.24 3.0  
Max 0.030 1.20 0.035 0.020 0.80 26.0 8.0 0.32 5.0 0.50


Duplex® and SuperDuplex® are registered trademarks of Sandvik AB, and the information herein is independent of Sandvik AB, and is not authorized by, endorsed by, sponsored by, affiliated with or otherwise approved by Sandvik AB. Monel® and Inconel® are registered trademarks of Special Metals Corp., and the information herein is independent of Special Metals Corp., and is not authorized by, endorsed by, sponsored by, affiliated with or otherwise approved by Special Metals Corp. 

Need more information? click here for a quote or call us at 713.466.1890 to speak with a Ram Alloys representative.