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Discover High-Quality Duplex Steel

Duplex 2205® Stainless Steel

UNS S31803 / UNS S32205

Duplex 2205® is a highly reliable stainless steel known for its balanced microstructure—containing approximately equal parts austenite and ferrite. This unique combination provides exceptional mechanical strength and corrosion resistance, especially in environments exposed to aggressive chemicals and chloride-bearing waters.

Originally developed over 70 years ago in Sweden for the sulfite paper industry, Duplex 2205® has evolved to become the go-to stainless steel in numerous industrial applications. The modern version includes deliberate additions of nitrogen, further enhancing its corrosion resistance—particularly in the UNS S32205 grade, which offers a slightly higher nitrogen content than UNS S31803.

Key Composition

  • Chromium: 21% – 23%
  • Nickel: 4.5% – 6.5%
  • Molybdenum: 2.5% – 3.5%
  • Manganese: up to 2%
  • Silicon: up to 1%
  • Balance: Iron
  • Trace elements: Carbon, Phosphorus, Sulfur, Nitrogen

Benefit

  • Excellent resistance to chloride stress corrosion cracking
  • High resistance to pitting, crevice corrosion, and erosion
  • Good weldability and workability
  • Strong mechanical properties
  • High resistance to sulfide stress corrosion
  • Better thermal conductivity and lower thermal expansion than austenitic grades
  • Over 80% of all Duplex stainless steel usage globally is Duplex 2205®—proven reliability across industries

Available Product Forms

  • Pipe: Seamless and Welded
  • Tubing: Seamless and Welded
  • Fittings: Butt Weld, Socket Weld
  • Flanges: ½” to 12” (Schedules 10s, 40s, 80s, 160 and XXH)
  • Pressure Fittings (Threaded): ¼” to 6” (150#, 300#, 3000#, 6000#)
  • Bar: Round, Flat, and Hex
  • Plate and Sheet

Specifications

  • Pipe: ASTM/ASME A/SA 790
  • Tubing: ASTM A789
  • Butt-Weld Fittings: ASTM/ASME A/SA 815
  • Sheet/Plate: ASTM A240
  • Flanges: ASTM/ASME A/SA 182
  • Bar: ASTM A276
  • Pressure Fittings: ASTM/ASME A/SA 182, A/SA 479

Chemical Composition %

C Cr Fe Mn Mo N Ni P S Si
MaxMaxMaxMaxMax
0.03021.0-23.0Bal2.02.50-3.500.08-0.204.50-6.500.030.021.0

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

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Super Duplex 2507® Stainless Steel

UNS S32750

Super Duplex 2507® is a high-performance stainless steel designed for demanding applications where superior corrosion resistance and strength are essential. It shares similarities with Duplex 2205® (UNS S31803), but offers higher chromium and nitrogen content, resulting in improved corrosion resistance and a longer service life.

With a balanced microstructure of ferrite and austenite, 2507® delivers an ideal blend of toughness and strength, along with excellent resistance to pitting, crevice corrosion, and chloride stress corrosion cracking—making it well-suited for harsh environments.

Key Composition

  • Chromium: 24% – 26%
  • Nickel: 6% – 8%
  • Molybdenum: ~3%
  • Manganese: ~1.2%
  • Balance: Iron
  • Trace Elements: Carbon, Phosphorus, Sulfur, Silicon, Nitrogen, Copper

Benefit

  • Exceptional resistance to chloride stress corrosion cracking
  • Superior protection against pitting and crevice corrosion
  • High strength and fatigue resistance
  • Good weldability and workability
  • High thermal conductivity and low thermal expansion
  • Excellent energy absorption under impact
  • Cost-effective alternative to high nickel alloys

Available From Inventory

  • Pipe: Seamless and Welded
  • Tubing: Seamless and Welded
  • Fittings: Butt Weld, Socket Weld
  • Flanges: ½” to 12”
  • Schedules: 10s, 40s, 80s, 160
  • Pressure Fittings (Threaded): ¼” to 6”
  • Ratings: 150#, 300#, 3000#, 6000#
  • Bar: Round, Flat, Hex
  • Plate and Sheet

Specifications

  • Pipe: ASTM/ASME A/SA 790
  • Tubing: ASTM A789
  • Butt-Weld Fittings: ASTM/ASME A/SA 815
  • Sheet/Plate: ASTM A240
  • Flanges: ASTM/ASME A/SA 182
  • Bar: ASTM A276
  • Pressure Fittings: ASTM/ASME A/SA 182, A/SA 479

Chemical Composition %

C Cr Mn Mo NI P S Si
MaxMaxMaxMaxMax
0.03024.0-26.01.23.0-5.06.0-8.00.0350.0200.80

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