Duplex 2205® Stainless Steel Bar

UNS S31803/UNS S32205

UNS S31803 and UNS S32205 are commonly referred to as Duplex 2205® material, whose “Duplex” name is derived from the mixed microstructure which contains about equal portions of ferrite and austenite. Developed more than 70 years ago in Sweden precisely for the sulfite paper industry where the Duplex’s were used to combat corrosion problems caused by chloride-bearing cooling waters and other aggressive chemical products. Since then there have been advancements in the composition such as the deliberate addition of nitrogen as an alloying agent, which afterwards quickly made Duplex the “workhorse” of stainless steels.

Generally, UNS S31803 has been solely designated to the Duplex 2205® grade. More recently, it has been available complying with the higher corrosion resistant composition UNS S32205. The only difference in the UNS numbers is that UNS S32205 contains a higher nitrogen content which guarantees better corrosion resistance. Composed of between 21% to 23% chromium, 4.5% to 6.5% nickel, 5% to 3.5% molybdenum, 2% manganese, and 1% silicon, with the balance being iron. Also found in Duplex Stainless Steel are trace amounts of carbon, phosphorus, sulfur and nitrogen.

Benefits of Duplex include: good weldability and workability, high resistance to corrosion fatigue, stress corrosion cracking (especially chloride stress corrosion cracking), erosion, and high energy absorption. Other advantages of Duplex are higher heat conductivity and low thermal expansion compared to austenitic stainless steels, high strength, good resistance to sulfide stress corrosion, and high resistance to pitting and crevice to corrosion. Duplex 2205® accounts for over 80% of the total usage of Duplex stainless steels throughout the world because of its superior workability as well as corrosion resistance.

Industries that use Duplex include:

  • Chemical
  • Desalination
  • Material handling
  • Oil and Gas extraction
  • Pulp and Paper
  • Petrochemical

Products partially or completely constructed of Duplex include:

  • Augers
  • Cargo tanks
  • Couplings
  • Diaphragm seals
  • Fans
  • Fasteners
  • Heat exchangers
  • Hubs
  • Instrumentation tubes
  • Pipe fittings
  • Press rolls
  • Pressure vessels
  • Rotors
  • Screw conveyors
  • Shafts
  • Valve parts
Stocking Diameters 1/2” to 14”
Material Lengths Up to 24’
Bar Specifications
Uns Type Ams Astm Federal Characteristics
S31803/S32205 Duplex
A-276
A-479
Roughly double the strength of standard austenitic stainless steels, designed to improve resistance in many applications such as chloride environments and sulfide stress corrosion.
Chemistry Analysis
C MN P S SI CR NI MO CU OTHER M/NM
.03 2. .03 .02 1. 21. – 23. 4.5 – 6.5 2.5 – 3.5 N .08 – .2 INQUIRE

2205® is a trademark of Sandvik Steel and is sold only through authorized distributors.
The information above is not warranted, guaranteed, or for design purposes.

The information above is not warranted, guaranteed, or for design purposes.

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