Data completeness: partial. Last verified 19 August 2026.
Designations
| Common name | Super duplex 2507 |
| UNS | S32750 |
| EN number | 1.4410 |
| Class | Super duplex stainless steel |
| Specified by | ASTM A240/A240M, EN 10088-2 |
A super duplex: higher chromium, molybdenum and nitrogen than 2205, and a PREN above 40, which is the conventional dividing line for seawater capability. The properties are not the reason it gets rejected — fabrication is. The phase-balance window is narrower still than 2205’s, and it is not a stock item in most thicknesses.
Properties, with what each one rests on
| Property | Value | Unit | Condition | Evidence | Source | Retrieved |
|---|---|---|---|---|---|---|
| Proof strength Rp0.2, minimum (EN) | 550 | MPa | cold rolled strip, 20 °C | E3 | EN 10088-2 via Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| Tensile strength Rm, minimum | 750 | MPa | cold rolled strip, EN 10088-2 | E3 | EN 10088-2 via Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| Elongation A80, minimum | 20 | % | cold rolled strip, EN 10088-2 | E3 | EN 10088-2 via Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| PREN | 43 | — | — | E3 | Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| Modulus of elasticity | 200 | GPa | 20 °C | E3 | Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-20 |
| Density | 7.8 | g/cm³ | 20 °C | E3 | Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| Thermal conductivity | 15 | W/(m·K) | 20 °C | E3 | Outokumpu Forta range datasheet — duplex and high-strength stainless steels | 2026-08-19 |
| Proof strength Rp0.2, minimum (ASTM plate) | not established | — | — | — | ASTM A240 is paywalled and no secondary source was checked for this grade | — |
| Composition limits | not established | — | — | — | ASTM A240 is paywalled | — |
7 sourced values, 2 gaps named. Publishing the gaps is more useful than filling them from an aggregator that does not say where its numbers came from. The routes to filling them are the standard itself, a mill datasheet, or a mill certificate for your actual heat — which supersedes both at E5.
Where the numbers come from
PREN. Reproduces from the datasheet’s own formula, PRE = %Cr + 3.3 × %Mo + 16 × %N, and its own typical composition of 25.0% Cr, 4.0% Mo and 0.27% N, which give 42.5 against the printed 43. Above 40, the conventional threshold for seawater service — which is a ranking observation, not a qualification. Crevice corrosion is not predicted by PREN and is the failure mode that usually decides seawater work.
Why we do not just copy an aggregator. Because then this page would be a worse copy of MatWeb with no way for you to tell which rows to trust, and the one thing we have that MatWeb does not is the evidence column. Our coverage and its limits.
What Super duplex 2507 is usually chosen for
Seawater and the aggressive end of chloride service, where 2205 is marginal. At the 550 MPa EN 10088-2 minimum it is also the strongest of the stainless grades on this site, so a strength-driven section in 2507 is thinner again than in 2205.
And what it is usually rejected for
Fabrication and supply, almost always. A narrower heat-input window than 2205, procedures that must be qualified specifically for it, and availability that is thin outside common thicknesses. A shop without a qualified procedure faces a new PQR and a lead time measured in weeks, and that is frequently decisive regardless of what the property table says.
The number to be more careful with than any of the above is the difference between a specified minimum and a typical value — a floor the standard guarantees, versus what a supplier’s production usually does. The full version, and the most expensive routine mistake in material data.
Compare
Super duplex 2507 vs 2205 · Super duplex 2507 vs 654smo
What this page does not cover
- The ASTM plate minimum is not established here.
- Crevice corrosion, which PREN does not predict and which usually decides seawater work.
- Elevated temperature: super duplex carries the same 475 °C embrittlement and sigma-phase constraints as 2205, and they arrive sooner. Not sourced here.
- Fatigue, fracture toughness and stress corrosion cracking.
- Cost, which is materially above 2205 and moves with alloy surcharges.
- Composition limits, not established.
Generated from data/materials/2507.yaml. Regenerate rather than editing this file by hand — edits here are lost on the next build.