X2CrNiMoN25-7-4 · S32750 · Super Duplex 2507 · EN 10253-4 Type B
Maximum pitting resistance among duplex grades — PRE ≥40. 25Cr-7Ni-4Mo-N. The specification for deep subsea, seawater desalination high-pressure circuits, and the most aggressive offshore chloride environments. Yield strength ≥530 MPa.
Super duplex 2507 has a higher sigma phase formation rate than standard duplex 2205 due to its higher Cr and Mo content. Solution annealing at 1080°C min followed by rapid water quench is required after any hot forming or welding that involves prolonged time in the 600–1000°C range. All EN 10253-4 fittings from Arshya are supplied in the solution-annealed condition. Sigma formation in service is prevented by keeping operating temperature below approximately 280°C.
Super duplex 2507 steps up from duplex 2205 in three ways: Cr is raised from 22% to 25%, Mo from 2.5–3.5% to 3.0–5.0%, and N from 0.10–0.22% to 0.24–0.32%. The combined effect pushes PRE from ≥35 to ≥40, and yield strength from ≥450 MPa to ≥530 MPa. This combination is specifically engineered for the most aggressive seawater environments — deep subsea where chloride concentrations and pressures are extreme, desalination concentrate circuits, and offshore produced-water treatment where standard duplex pits.
The tradeoff is tighter process windows: forming temperatures are narrower, sigma phase sensitisation is faster, and heat input control in welding is more critical. Solution annealing after forming is non-negotiable.
| Element | 1.4462 (Duplex 2205) | 1.4410 (Super Duplex 2507) |
|---|---|---|
| Chromium (Cr) | 21.0–23.0% | 24.0–26.0% |
| Nickel (Ni) | 4.5–6.5% | 6.0–8.0% |
| Molybdenum (Mo) | 2.5–3.5% | 3.0–5.0% |
| Nitrogen (N) | 0.10–0.22% | 0.24–0.32% |
| PRE (typical) | ≥35 | ≥40 |
| Yield strength | ≥450 MPa | ≥530 MPa |
| Filler | ER2209 | ER2594 |
| EN number | 1.4410 |
| EN designation | X2CrNiMoN25-7-4 |
| UNS | S32750 |
| PRE (min) | ≥40 |
| Yield strength | ≥530 MPa |
| NACE MR0175 | Compliant |
| Max service temp | ≤280°C |
| Filler (GTAW) | ER2594 |
| Supply condition | Solution annealed + quenched |
| Standard | EN 10253-4 Type B |
| Certificate | EN 10204 3.1 standard |
NACE MR0175 hardness certificate. EN 10204 3.1. PMI on every order. Solution annealed and water quenched. 3.2 (Lloyd's / DNV / BV) available.
Get QuoteDN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.
| Size | OD (mm) |
|---|---|
| DN 15 | 21.3 |
| DN 20 | 26.9 |
| DN 25 | 33.7 |
| DN 32 | 42.4 |
| DN 40 | 48.3 |
| DN 50 | 60.3 |
| DN 65 | 76.1 |
| DN 80 | 88.9 |
| DN 100 | 114.3 |
| DN 125 | 139.7 |
| DN 150 | 168.3 |
| DN 200 | 219.1 |
| DN 250 | 273.0 |
| DN 300 | 323.9 |
| DN 350 | 355.6 |
| DN 400 | 406.4 |
| DN 450 | 457.0 |
| DN 500 | 508.0 |
| DN 600 | 610.0 |
2507 has higher pitting resistance (PRE at least 40 vs 35) and higher minimum yield strength (530 MPa vs 450 MPa), for deep subsea, desalination high-pressure circuits and the most aggressive chloride service.
Hot forming can leave harmful phases in the microstructure, so the fittings are solution annealed at 1080°C minimum and rapidly water quenched.
Service up to about 280°C; ER2594 filler for GTAW.
Supplying an Indian boiler or ASME B16.9 project? The equivalent grade is listed on our group site ibrfittings.com: Super Duplex 2507 fittings.
