European designation reference for the Cu-bearing super duplex stainless steel UNS S32550
EN 1.4507 (Werkstoff 1.4507) is the European Standard material number for the Cu-bearing super duplex stainless steel commercially known as Ferralium 255. The corresponding EN steel name X2CrNiMoCuN25-6-3 follows the EN 10027-1 nomenclature convention: X (high-alloy steel), 2 (carbon × 100, so max 0.02% nominal C, actual cap 0.040%), CrNiMoCuN (the principal alloying elements in descending atomic-percent order), 25-6-3 (the chromium-nickel-molybdenum nominal percentages rounded). The 1.4507 number cross-references to UNS S32550 in the North American system. The grade is covered by EN 10088-3 (long products), EN 10088-2 (flat products), EN 10222-5 (forgings for pressure purposes), EN 10272 (bar for pressure purposes), and EN 10216-5 (seamless pressure pipe).
| EN standard | Product form | USA equivalent |
|---|---|---|
| EN 10088-2 | Flat products (plate, sheet, strip) for general use | ASTM A240 |
| EN 10088-3 | Long products (bar, rod, wire, sections) for general use | ASTM A479, A276 |
| EN 10222-5 | Forgings for pressure purposes | ASTM A182 grade F61 |
| EN 10272 | Bar for pressure purposes | ASTM A479 |
| EN 10216-5 | Seamless pressure pipe | ASTM A790 |
| EN 10217-7 | Welded pressure pipe | ASTM A928 / A790 welded |
| EN 10204 type 3.2 | Inspection certificate (third-party witnessed MTC) | (EN-only, no direct ASTM equivalent) |
| EN ISO 15156-3 | Sour-service material qualification | NACE MR0175 (harmonised) |
| Element | Min % | Max % |
|---|---|---|
| Carbon (C) | none | 0.030 |
| Manganese (Mn) | none | 2.00 |
| Phosphorus (P) | none | 0.035 |
| Sulphur (S) | none | 0.015 |
| Silicon (Si) | none | 1.00 |
| Chromium (Cr) | 24.0 | 27.0 |
| Nickel (Ni) | 4.5 | 6.5 |
| Molybdenum (Mo) | 2.9 | 3.9 |
| Copper (Cu) | 1.5 | 2.5 |
| Nitrogen (N) | 0.10 | 0.25 |
The EN 10088-3 limits are slightly tighter than ASTM A479 on the impurity elements (P, S) reflecting the European emphasis on per-cast traceability for pressure-vessel service. Production heats typically meet both specs simultaneously and the MTC dual-certifies to ASTM A479 + EN 10088-3 / EN 10272.
