F51 (UNS S31803)
USExact matchASTM/ASME · ASTM A182/A182M (ASME SA-182)
Austenitic-ferritic (duplex) chromium-nickel-molybdenum-nitrogen stainless steel, the most widely used grade in the duplex family. Extensively used in offshore oil & gas piping and flanges for its resistance to pitting and stress-corrosion cracking in seawater/chloride environments, with a yield strength roughly double that of standard austenitic stainless steels (304/316). Not recommended above 300°C (embrittlement) or below -50°C (ductile-to-brittle transition).
| Grade | Region | Standard | Re (MPa) | Rm (MPa) | Delta |
|---|---|---|---|---|---|
| F51 (UNS S31803) | US | ASTM A182/A182M (ASME SA-182) | 450 | ≥620 | reference |
| 1.4462 (X2CrNiMoN22-5-3) | EU | EN 10222-5 | 450 | 640–920 | 0% |
| F60 (UNS S32205) | US | ASTM A182/A182M (ASME SA-182) | 450 | ≥655 | 0% |
| Insufficient mechanical data to compare | |||||
| SUS329J3L | JP | JIS G4304 / G4303 / G3459 | — | — | — |
| STS329J3L | KR | KS D 3706 | — | — | — |
| X2CrNiMoN22-5-3 | ISO | ISO 15510 | — | — | — |
| Grade | C | Mn | Si | P | S | Cr | Ni | Mo | N |
|---|---|---|---|---|---|---|---|---|---|
| F51 (UNS S31803) | ≤0.03 | ≤2 | ≤1 | ≤0.03 | ≤0.02 | 21–23 | 4.5–6.5 | 2.5–3.5 | 0.08–0.2 |
| 1.4462 (X2CrNiMoN22-5-3) | ≤0.03 | ≤2 | ≤1 | ≤0.035 | ≤0.015 | 21–23 | 4.5–6.5 | 2.5–3.5 | 0.1–0.22 |
| F60 (UNS S32205) | ≤0.03 | ≤2 | ≤1 | ≤0.03 | ≤0.02 | 22–23 | 4.5–6.5 | 3–3.5 | 0.14–0.2 |
| SUS329J3L | ≤0.03 | ≤2 | ≤1 | ≤0.04 | ≤0.03 | 21–24 | 4.5–6.5 | 2.5–3.5 | 0.08–0.2 |
| STS329J3L | ≤0.03 | ≤2 | ≤1 | ≤0.04 | ≤0.03 | 21–24 | 4.5–6.5 | 2.5–3.5 | 0.08–0.2 |
| X2CrNiMoN22-5-3 | ≤0.03 | ≤2 | ≤1 | — | — | 21–23 | 4.5–6.5 | 2.5–3.5 | 0.1–0.22 |
Note: The historical and most-cited reference for forged duplex 2205 flanges/fittings/valves (forged form confirmed by the brief). Slightly wider composition range than F60 (minimum nitrogen 0.08% vs. 0.14%), which explains why S31803/S32205 coexist under the same commercial name "2205".
Values compiled from public sources for guidance only — always verify against the official standard before use in design or fabrication.