Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175 / ISO 15156-2
- NORSOK M-650 Qualified
- API 6A Certified
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Werkstoff 1.4410, X2CrNiMoN25-7-4 (EN 10088-3)
Werkstoff 1.4410 is the European Material Number for super duplex stainless steel under EN 10088-3. The full EN designation is X2CrNiMoN25-7-4, where X means low-carbon, 2 means 0.02 percent carbon nominal, Cr-Ni-Mo-N are the alloying elements, and 25-7-4 are the nominal weight percents (25 percent chromium, 7 percent nickel, 4 percent molybdenum). Nitrogen percentage is implicit in the X-prefix nomenclature; the actual nitrogen window is 0.24 to 0.32 percent.
1.4410 is the European registry equivalent of UNS S32750 in the American Unified Numbering System. The chemistry windows in EN 10088-3 and ASTM A479 / A790 are identical within negligible tolerance, and mill test certificates routinely cite both designations. Mill trademarks for the same chemistry include SAF 2507 (Sandvik), UR 52N+ (Industeel ArcelorMittal) and Avesta 2507 (Outokumpu).
Designation Breakdown
EN 10088-3 uses two parallel designation systems:
- Werkstoff Nummer (Material Number): 1.4410. The "1" is the steel group, the "4" is the stainless category, and "410" is the unique grade identifier.
- Steel name: X2CrNiMoN25-7-4. The "X" denotes high-alloy steel; "2" is 0.02 percent carbon; "CrNiMoN" lists the principal alloying elements; "25-7-4" gives the nominal weight percents of chromium, nickel and molybdenum.
Composition (EN 10088-3)
| Element | EN 10088-3 Min % | EN 10088-3 Max % | Typical Mill Heat |
|---|---|---|---|
| Carbon (C) | (no min) | 0.030 | 0.020 |
| Manganese (Mn) | (no min) | 2.00 | 0.80 |
| Phosphorus (P) | (no min) | 0.035 | 0.025 |
| Sulfur (S) | (no min) | 0.015 | 0.001 |
| Silicon (Si) | (no min) | 1.00 | 0.40 |
| Chromium (Cr) | 24.0 | 26.0 | 25.0 |
| Nickel (Ni) | 6.0 | 8.0 | 7.0 |
| Molybdenum (Mo) | 3.0 | 5.0 | 3.8 |
| Nitrogen (N) | 0.24 | 0.35 | 0.28 |
| Copper (Cu) | (no min) | 0.50 | 0.20 (residual, not intentional) |
| PREN | 41 to 43 (Cr + 3.3 times Mo + 16 times N) | ||
The 1.4410 chemistry matches UNS S32750 within negligible tolerance. The slightly wider nitrogen ceiling (0.35 percent in EN vs 0.32 percent in ASTM A479) reflects historical differences between European and American standards. Most mills supply 1.4410 / S32750 dual-certified to both standards.
International Equivalents
| Region or Standard | Designation |
|---|---|
| Europe (EN 10088-3) | 1.4410 / X2CrNiMoN25-7-4 |
| USA (UNS) | S32750 |
| USA (ASTM forgings) | ASTM A182 F53 |
| USA (ASTM bar) | ASTM A479 UNS S32750 |
| USA (ASTM pipe) | ASTM A790 UNS S32750 |
| USA (ASTM fittings) | ASTM A815 WP-S32750 |
| Norway (NORSOK MDS) | NORSOK M-630 MDS D55, D57 |
| Sandvik trademark | SAF 2507 |
| Industeel ArcelorMittal trademark | UR 52N+ |
| Outokumpu trademark | Avesta 2507 |
Mechanical Properties (EN 10088-3)
| Property | 1.4410 Minimum | Test Standard |
|---|---|---|
| Yield strength (0.2 percent offset) | 530 MPa (longitudinal), 480 MPa (transverse) | EN ISO 6892 |
| Tensile strength | 730 to 930 MPa | EN ISO 6892 |
| Elongation | 20 percent | EN ISO 6892 |
| Hardness | 270 HB max | EN ISO 6506 |
| Charpy V-notch at minus 40 degrees Celsius | 60 J min | EN ISO 148-1 |
EN Standards Covering 1.4410
| Standard | Scope |
|---|---|
| EN 10088-1 | Stainless steels: list of stainless steels |
| EN 10088-2 | Sheet, plate and strip for general purposes |
| EN 10088-3 | Bars, rods, wire, sections, semi-finished products (where 1.4410 is registered) |
| EN 10216-5 | Seamless steel tube for pressure purposes (stainless) |
| EN 10217-7 | Welded steel tube for pressure purposes (stainless) |
| EN 10222-5 | Forgings for pressure purposes (martensitic, austenitic and duplex) |
| EN 10272 | Stainless steel bars for pressure purposes |
| EN ISO 3506-1 | Mechanical properties of stainless steel fasteners |
1.4410 Product Forms
1.4410 / S32750 is supplied across the full duplex product range. TorqBolt holds 2507 stock at the Mumbai warehouse certified to both EN 10088-3 (1.4410) and ASTM A479 (S32750), with Type 3.1 mill test certificates per EN 10204 standard, and Type 3.2 third-party-witnessed certificates available on request.
- Bar (round, hex, flat, square, forged, hollow, cold-finished)
- Sheet, plate, pipe, tube, welded pipe, wire and welding wire
- Buttweld fittings, flanges, forgings
- Fasteners: hex bolts, heavy hex bolts, stud bolts, eye bolts, U-bolts, hex nuts, heavy hex nuts, lock nuts, washers, flat washers, lock washers, socket head cap screws
Werkstoff 1.4410 Frequently Asked Questions
What is Werkstoff 1.4410?
Werkstoff 1.4410 is the European Material Number for super duplex stainless steel registered in EN 10088-3 with the steel name X2CrNiMoN25-7-4. The chemistry is 25 percent chromium, 7 percent nickel, 4 percent molybdenum, 0.24 to 0.32 percent nitrogen, with no intentional copper or tungsten. PREN sits at 41 to 43.
Is 1.4410 the same as UNS S32750?
Yes. Werkstoff 1.4410 (European EN 10088-3) and UNS S32750 (American Unified Numbering System) refer to the same super duplex stainless steel chemistry within negligible tolerance. Mill test certificates routinely cite both designations as dual certification.
What does X2CrNiMoN25-7-4 mean?
The "X" denotes a high-alloy steel. The "2" indicates 0.02 percent carbon nominal. "Cr-Ni-Mo-N" lists the principal alloying elements (chromium, nickel, molybdenum, nitrogen). "25-7-4" gives the nominal weight percents of chromium (25), nickel (7) and molybdenum (4). Nitrogen percentage is implicit in the prefix.
Which mills produce 1.4410?
European mills producing 1.4410 include Sandvik (under SAF 2507), Industeel ArcelorMittal (UR 52N+), Outokumpu (Avesta 2507), Salzgitter, and ThyssenKrupp. The chemistry is identical to UNS S32750 from American producers.
What standards cover 1.4410?
EN 10088-3 (bar, rod, wire, sections), EN 10088-2 (sheet, plate, strip), EN 10216-5 (seamless tube), EN 10217-7 (welded tube), EN 10222-5 (forgings), EN 10272 (bar for pressure), EN ISO 3506-1 (fasteners). 1.4410 is also dual-certified to ASTM A479, A790, A815 and A182 F53 for international project compliance.
Is 1.4410 available with NORSOK M-630 compliance?
Yes. 1.4410 is supplied to NORSOK M-630 MDS D55 (forgings, bar, plate) and D57 (pipe and tube), with PREN 40 minimum requirement, ferrite content 35 to 55 percent in base metal, and Charpy 45 J minimum at minus 46 degrees Celsius. NORSOK M-650 manufacturer qualification (QTR) is required for Norwegian Continental Shelf supply.
Is 1.4410 acceptable for sour service?
Yes, qualified per NACE MR0175 / ISO 15156-3 with hardness restricted to 28 HRC maximum and ferrite content within 35 to 65 percent. Specific H2S partial pressure and chloride limits depend on the application zone classification under ISO 15156. TorqBolt supplies 1.4410 fasteners and forgings with NACE compliance certification on request.
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