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Duplex Steel

Duplex and Super Duplex stainless steels are advanced alloys known for their exceptional strength, high corrosion resistance, and superior mechanical properties. These steels have a unique dual-phase microstructure, combining both austenitic and ferritic phases, which provides enhanced toughness, increased durability, and resistance to stress corrosion cracking. Compared to conventional stainless steels, Duplex and Super Duplex offer higher strength, improved resistance to pitting and crevice corrosion, and better performance in extreme environments.
ASTM/ASME
Duplex & Super Duplex Specifications
Standard
ASTM, ASME, EN, DIN, ISO, JIS
Grades
Duplex 2205 (UNS S31803/S32205), Super Duplex 2507 (UNS S32750/S32760), UNS S32550, UNS S32950, UNS S31254
Applications
Oil & Gas, Marine, Offshore Structures, Chemical Processing, Desalination Plants, Pulp & Paper, Power Generation, Heat Exchangers, Pressure Vessels
ASTM/ASME
A182, A240, A276, A479, A789, A790, A815, A928, A995
Forms and Products
Pipes and Tubes, Buttweld Fittings, Flanges, Forged Fittings, Sheets, Plates, and Coils, Bars and Rods, Fasteners, Filler Wire, Outlet
Properties
High Strength, Excellent Corrosion Resistance, Superior Stress Corrosion Cracking (SCC) Resistance, High Pitting and Crevice Corrosion Resistance, Improved Weldability
Available in all grades
Duplex & Super Duplex Products






ASTM / ASME
Equivalent Grades
Steel Grade | Type | ASTM | EN (DIN) | BS | JIS | GOST |
---|---|---|---|---|---|---|
UNS S31803 | Duplex | A790/A815 | 1.4462 | 32205S31 | SUS329J3L | 08X18H10 |
UNS S32205 | Duplex | A790/A815 | 1.4410 | 32205S31 | SUS329J3L | 08X19H10 |
UNS S32750 | Super Duplex | A790/A815 | 1.4410 | 2507S31 | SUS329J3L | 08X22H6 |
UNS S32760 | Super Duplex | A790/A815 | 1.4501 | 2507S31 | SUS329J4L | 08X23H6 |
ASME / ASTM
Chemical Composition
Grade | C | Mn | Si | P | S | Cr | Ni | Mo | N | Fe |
---|---|---|---|---|---|---|---|---|---|---|
Duplex (UNS S31803) | ≤ 0.03 | 1.0-2.0 | 0.5-1.0 | ≤ 0.03 | ≤ 0.01 | 18.0-20.0 | 4.5-6.5 | 2.5-3.5 | 0.08-0.2 | Balance |
Duplex (UNS S32205) | ≤ 0.03 | 1.0-2.0 | 0.5-1.0 | ≤ 0.03 | ≤ 0.01 | 22.0-24.0 | 4.5-6.5 | 3.0-4.0 | 0.10-0.20 | Balance |
Super Duplex (UNS S32750) | ≤ 0.03 | 1.0-2.0 | 0.5-1.0 | ≤ 0.03 | ≤ 0.01 | 24.0-26.0 | 6.0-8.0 | 3.5-4.5 | 0.20-0.30 | Balance |
Super Duplex (UNS S32760) | ≤ 0.03 | 1.0-2.0 | 0.5-1.0 | ≤ 0.03 | ≤ 0.01 | 25.0-27.0 | 6.0-8.0 | 4.0-5.0 | 0.20-0.30 | Balance |
ASME / ASTM
Mechanical Properties
Property | Duplex (UNS S31803) | Duplex (UNS S32205) | Super Duplex (UNS S32750) | Super Duplex (UNS S32760) |
---|---|---|---|---|
Tensile Strength (MPa) | ≥ 620 | ≥ 620 | ≥ 750 | ≥ 800 |
Yield Strength (MPa) | ≥ 450 | ≥ 450 | ≥ 550 | ≥ 600 |
**Elongation (%) | ≥ 25 | ≥ 25 | ≥ 25 | ≥ 25 |
Hardness (HB) | ≤ 300 | ≤ 300 | ≤ 300 | ≤ 300 |
Impact Toughness (J) | ≥ 40 (at -40°C) | ≥ 40 (at -40°C) | ≥ 50 (at -40°C) | ≥ 50 (at -40°C) |