Duplex stainless steel (DSS) is featured with structure of two phases (α and γ) and has characteristics of both ferritic and austenitic stainless steel. It has good corrosion resistance and high strength. It is alloyed with 18%-28% Cr and 3%-10% Ni in the condition of low C. Some steels also contain the alloy elements such as Mo, Cu, Nb, Ti and N, etc.
Specifications of Duplex Pipes
Standard | |
ASTM A789/SA789 | Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service |
ASTM A790/SA790 | Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe |
ASTM A928 (ASME SA928) | Standard Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal |
Duplex 2507 (UNS S32750) | |
Steel Grade | |
Duplex 2507 (UNS S32750) | is a super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel designed. |
Duplex 2205 (UNS S31803) | or Avesta Sheffield 2205 is a ferritic-austenitic stainless steel. |
SUPER DUPLEX UNS S32760 | is a super duplex stainless steel, so-called due to its higher Chromium and Molybdenum content. |
ASTM Referenced Standards | |
A450 A450M | Specification for General requirements for carbon, Ferritic Alloy, and Austenitic alloy steel tubes. |
A480 A480M | Specification for general requirements for flat-rolled stainless and heat-resisting steel plate, sheet, and strip. |
A941 | Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys. |
E527 | Practice for numbering metals and alloys (UNS). |
ASTM A789 A789M | Covers Grades of nominal wall thickness, stainless steel tubing for services requiring general corrosion resistance, with particular emphasis on resistance to stress corrosion cracking. |
List Of Duplex Pipe Types
Duplex Pipe Composition Standard
Steel designation | Number | C, max | Si | Mn | P, max | S, max. | N | Cr | Cu | Mo | Ni | Other |
X2CrNiN22-2 | 1.4062 | 0.03 | ≤1.00 | ≤2.00 | 0.04 | 0.010 | 0.16 to 0.28 | 21.5 to 24.0 | - | ≤0.45 | 1.00 to 2.90 | - |
X2CrCuNiN23-2-2 | 1.4669 | 0.045 | ≤1.00 | 1.00 to 3.00 | 0.04 | 0.030 | 0.12 to 0.20 | 21.5 to 24.0 | 1.60 to 3.00 | ≤0.50 | 1.00 to 3.00 | - |
X2CrNiMoSi18-5-3 | 1.4424 | 0.03 | 1.40 to 2.00 | 1.20 to 2.00 | 0.035 | 0.015 | 0.05 to 0.10 | 18.0 to 19.0 | - | 2.5 to 3.0 | 4.5 to 5.2 | - |
X2CrNiN23-4 | 1.4362 | 0.03 | ≤1.00 | ≤2.00 | 0.035 | 0.015 | 0.05 to 0.20 | 22.0 to 24.5 | 0.10 to 0.60 | 0.10 to 0.60 | 3.5 to 5.5 | - |
X2CrMnNiN21-5-1 | 1.4162 | 0.04 | ≤1.00 | 4.0 to 6.0 | 0.040 | 0.040 | 0.20 to 0.25 | 21.0 to 22.0 | 0.10 to 0.80 | 0.10 to 0.80 | 1.35 to 1.90 | - |
X2CrMnNiMoN21-5-3 | 1.4482 | 0.03 | ≤1.00 | 4.0 to 6.0 | 0.035 | 0.030 | 0.05 to 0.20 | 19.5 to 21.5 | ≤1.00 | 0.10 to 0.60 | 1.50 to 3.50 | - |
X2CrNiMoN22-5-3 | 1.4462 | 0.03 | ≤1.00 | ≤2.00 | 0.035 | 0.015 | 0.10 to 0.22 | 21.0 to 23.0 | - | 2.50 to 3.50 | 4.5 to 6.5 | - |
X2CrNiMnMoCuN24-4-3-2 | 1.4662 | 0.03 | ≤0.70 | 2.5 to 4.0 | 0.035 | 0.005 | 0.20 to 0.30 | 23.0 to 25.0 | 0.10 to 0.80 | 1.00 to 2.00 | 3.0 to 4.5 | - |
X2CrNiMoCuN25-6-3 | 1.4507 | 0.03 | ≤0.70 | ≤2.00 | 0.035 | 0.015 | 0.20 to 0.30 | 24.0 to 26.0 | 1.00 to 2.50 | 3.0 to 4.0 | 6.0 to 8.0 | - |
X3CrNiMoN27-5-2 | 1.4460 | 0.05 | ≤1.00 | ≤2.00 | 0.035 | 0.015 | 0.05 to 0.20 | 25.0 to 28.0 | - | 1.30 to 2.00 | 4.5 to 6.5 | - |
X2CrNiMoN25-7-4 | 1.4410 | 0.03 | ≤1.00 | ≤2.00 | 0.035 | 0.015 | 0.24 to 0.35 | 24.0 to 26.0 | - | 3.0 to 4.5 | 6.0 to 8.0 | - |
X2CrNiMoCuWN25-7-4 | 1.4501 | 0.03 | ≤1.00 | ≤1.00 | 0.035 | 0.015 | 0.20 to 0.30 | 24.0 to 26.0 | 0.50 to 1.00 | 3.0 to 4.0 | 6.0 to 8.0 | W 0.50 to 1.00 |
X2CrNiMoN29-7-2 | 1.4477 | 0.03 | ≤0.50 | 0.80 to 1.50 | 0.030 | 0.015 | 0.30 to 0.40 | 28.0 to 30.0 | ≤0.80 | 1.50 to 2.60 | 5.8 to 7.5 | - |
X2CrNiMoCoN28-8-5-1 | 1.4658 | 0.03 | ≤0.50 | ≤1.50 |
| 0.010 | 0.30 to 0.50 | 26.0 to 29.0 | ≤1.00 | 4.0 to 5.0 | 5.5 to 9.5 | Co 0.50 to 2.00 |
X2CrNiCuN23-4 | 1.4655 | 0.03 | ≤1.00 | ≤2.00 | 0.015 | 0.015 | 0.05 to 0.20 | 22.0 to 24.0 | 1.00 to 3.00 | 0.10 to 0.60 | 3.5 to 5.5 | - |
Duplex Pipes Mechanical properties
Grade | Tensile strength, min., ksi [MPa] | Yield strength, min., ksi [MPa] | Elongation in 2 in., or 50mm, min, % | Hardness, MaxBrinell |
S31803 | 90 [620] | 65 [450] | 25 | 290 |
S32205 | 95 [655] | 70 [485] | 25 | 290 |
S31500 | 92 [630] | 64 [440] | 30 | 290 |
S32550 | 110 [760] | 80 [550] | 15 | 297 |
S31200 | 100 [690] | 65 [450] | 25 | 280 |
S31260 | 100 [690] | 65 [450] | 25 | 290 |
S32001 | 90 [620] | 65 [450] | 25 | 290 |
S32304 | 100 [690] | 65 [450] | 25 | 290 |
S32750 | 116 [800] | 80 [550] | 15 | 310 |
S32760 | 109 [750] | 80 [550] | 25 | 300 |
S32950 | 100 [690] | 70 [480] | 20 | 290 |
S32520 | 112 [770] | 80 [550] | 25 | 310 |