Duplex & super duplex / UNS S31803 / S32205
Duplex 2205 is a 22% chromium, 5% nickel, 3% molybdenum ferritic-austenitic stainless steel with about twice the yield strength of 316L and far better resistance to chloride stress-corrosion cracking. S32205 is the tighter, higher-nitrogen variant.
- UNS S31803 / S32205
- W.Nr. 1.4462
- Spec ASTM A240 (S31803)
- Density 7.8 g/cm³
Also known as / equivalents
| System | Designation |
|---|---|
| UNS | S31803 / S32205 |
| W.Nr. | 1.4462 |
| EN | X2CrNiMoN22-5-3 |
| JIS | SUS329J3L |
| Also known as | 2205, F51, F60, S31803, S32205, 1.4462, SUS329J3L |
Chemical composition
| Element | Min % | Max % |
|---|---|---|
| C | — | 0.030 |
| Mn | — | 2.00 |
| P | — | 0.030 |
| S | — | 0.020 |
| Si | — | 1.00 |
| Cr | 21.0 | 23.0 |
| Ni | 4.5 | 6.5 |
| Mo | 2.5 | 3.5 |
| N | 0.08 | 0.20 |
| Fe | Bal. | — |
| Element | Min % | Max % |
|---|---|---|
| C | — | 0.030 |
| Mn | — | 2.00 |
| P | — | 0.030 |
| S | — | 0.020 |
| Si | — | 1.00 |
| Cr | 22.0 | 23.0 |
| Ni | 4.5 | 6.5 |
| Mo | 3.0 | 3.5 |
| N | 0.14 | 0.20 |
| Fe | Bal. | — |
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength (min) | 620 MPa (89.9 ksi) |
| Yield strength, 0.2% offset (min) | 450 MPa (65.3 ksi) |
| Elongation in 50 mm (min) | 25 % |
| Hardness | 293 HB max |
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.8 g/cm³ | 0.282 lb/in³ |
| Magnetic response | Magnetic (ferritic-austenitic) | — |
Available forms & specifications
| Form | Specification | Size range |
|---|---|---|
| Sheets, plates & coils | ASTM A240 / ASME SA240 | 0.3 mm – 6 mm |
| Seamless & welded pipe | ASTM A790 / A928 | 1/8" – 24" NB |
| Tubes | ASTM A789 | 1/8" – 24" NB |
| Bars & rods | ASTM A276, A479 | 3 mm – 500 mm |
| Flanges & forgings | ASTM A182 / ASME SA182 (F51, F53, F55, F60, F61, F44) | 1/2" – 48" NB (larger on request) |
| Buttweld fittings | ASTM A815 | 1/2" – 48" NB |
Corrosion & temperature resistance
Duplex grades combine high strength with resistance to chloride pitting, crevice corrosion and stress-corrosion cracking; super duplex grades (PREN ≥ 40) are used for seawater and aggressive brines. Service is normally limited to about 250–300 °C because of embrittlement at higher temperatures.
Applications
Duplex 2205: Offshore piping, heat exchangers, tanks. Offshore and subsea piping, desalination, chemical tankers, pulp bleaching, heat exchangers and pressure vessels where weight saving matters.
Duplex 2205 vs Super Duplex 2507
| Duplex 2205 | Super Duplex 2507 | |
|---|---|---|
| UNS | S31803 / S32205 | S32750 |
| Key property | 2× strength of 316L, chloride-SCC resistant | PREN > 40, seawater grade |
| Typical use | Offshore piping, heat exchangers, tanks | Seawater systems, desalination, subsea |
| Cr (wt %) | 21.0–23.0 | 24.0–26.0 |
| Ni (wt %) | 4.5–6.5 | 6.0–8.0 |
| Mo (wt %) | 2.5–3.5 | 3.0–5.0 |
| C (wt %) | ≤ 0.030 | ≤ 0.030 |
| Tensile / yield (min, MPa) | 620 / 450 | 795 / 550 |
Frequently asked questions
What is the UNS number of Duplex 2205?
Duplex 2205 is designated UNS S31803 / S32205 (W.Nr. 1.4462, EN X2CrNiMoN22-5-3).
What is Duplex 2205 used for?
2× strength of 316L, chloride-SCC resistant. Typical uses: offshore piping, heat exchangers, tanks.
Is Duplex 2205 magnetic?
Magnetic (ferritic-austenitic).
In which forms can I buy Duplex 2205 from Rajkamal Metals?
Coils & Strips, Sheets & Plates, Pipes & Tubes, Round Bars & Rods, Structural Sections, Flanges, Buttweld Fittings, Socket Weld & Threaded Fittings, Fasteners, Ferrule / Instrumentation Fittings, Dish Ends, Custom Orders. Sizes as per standard; other sizes on request.
Do you supply a Mill Test Certificate with Duplex 2205?
Yes. Actual values are given in the Mill Test Certificate (EN 10204 3.1) supplied with each order.
What is the difference between Duplex 2205 and Super Duplex 2507?
Duplex 2205: 2× strength of 316l, chloride-scc resistant. Super Duplex 2507: pren > 40, seawater grade. See the comparison table on this page.
Last updated: 30 October 2026. Grade names identify the supply range; designations are not engineering equivalents. Availability, make, origin and documentation are confirmed at quotation.
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