Super Duplex 2507 (UNS S32750) Instrumentation Fittings, Valves & Tubing
Super Duplex 2507 (UNS S32750, EN 1.4410) is a 25% chromium super-duplex stainless steel with a roughly 50/50 ferrite-austenite microstructure, a PREN above 42, and close to twice the yield strength of standard 316, engineered for warm-chloride, seawater, and sour-service instrumentation where austenitic grades pit and stress-corrosion-crack. Crestflo supplies Super Duplex 2507 as finished instrumentation hardware: compression tube fittings, instrumentation valves, and tubing, not mill plate or structural bar.
On this page, Super Duplex 2507, the super duplex 2507 material also written super duplex grade 2507 or grade 2507, means UNS S32750 super-duplex stainless for fluid-system instrumentation components. It is a distinct grade from standard Duplex 2205 (S31803/S32205) and from Zeron 100 (S32760); this page does not cover structural plate, bar mill stock, or welding consumables. Ready stock for standard items, made-to-order for specials, 6-8 week delivery. Request a quote for your bill of materials.
What Is Super Duplex 2507 (UNS S32750) Stainless Steel?
Super Duplex 2507 is a nitrogen-enhanced super-duplex stainless steel whose two-phase austenite-plus-ferrite structure combines the chloride-pitting resistance and strength of duplex metallurgy with high alloy content, nominally 25% chromium, 7% nickel, 4% molybdenum, and controlled nitrogen. The "super" prefix denotes a Pitting Resistance Equivalent Number (PREN) above 40, which places 2507 between standard Duplex 2205 and the nickel-based alloys in the corrosion-resistant-alloy hierarchy. Its balanced duplex phase ratio gives it a minimum yield strength roughly double that of an austenitic 316/316L, so thinner walls carry the same pressure and instrumentation assemblies resist deformation and chloride stress-corrosion cracking in service where 316 or 2205 is under-alloyed. Yes, 2507 is a stainless steel, a super-duplex stainless, not a nickel alloy, and it is a fully weldable, machinable engineering grade for offshore, seawater, petrochemical, and sour-gas fluid systems.
Super Duplex 2507 Designations: UNS S32750, EN 1.4410, ASTM F53 & SAF 2507
Across catalogs, drawings, and material call-outs, this grade is specified under several names. It is written as Super Duplex 2507, 2507 super duplex, Alloy 2507 or 2507 alloy, Duplex 2507 or 2507 duplex, SD2507, and super duplex stainless steel 2507. Its formal designations are UNS S32750 and EN / Werkstoff 1.4410 (EN name X2CrNiMoN25-7-4). In forged and fitting form it maps to ASTM A182 Grade F53, the F53 super duplex forging grade. SAF™ 2507 is Alleima's (formerly Sandvik's) trademark for the same S32750 grade and is referenced here for identification only; Crestflo is not affiliated with Alleima. Zeron® 100 (UNS S32760, a Rolled Alloys trademark) is a closely related super-duplex grade but is a distinct UNS number, not an exact equivalent of S32750.
| Designation system | Super Duplex 2507 designation |
|---|---|
| UNS | S32750 |
| EN / Werkstoff (W.Nr.) | 1.4410 |
| EN steel name | X2CrNiMoN25-7-4 |
| ASTM forged / fitting grade | A182 F53 |
| Trade name (attributed) | SAF™ 2507 (Alleima) |
| Common / shop names | Alloy 2507, Duplex 2507, SD2507 |
| Related but distinct grade | Zeron® 100 (UNS S32760) |
Super Duplex 2507 Chemical Composition (25Cr-7Ni-4Mo-N)
The composition below reflects the standard published limits for UNS S32750; the high chromium, molybdenum, and nitrogen together drive the grade's pitting resistance, while the balanced nickel keeps the ferrite-austenite ratio near 50/50. Values are per the applicable ASTM/EN specification and are customizable to requirement; actual per-heat chemistry is reported on the material test certificate that ships with each order.
| Element | Min % | Max % |
|---|---|---|
| Chromium (Cr) | 24.0 | 26.0 |
| Nickel (Ni) | 6.0 | 8.0 |
| Molybdenum (Mo) | 3.0 | 5.0 |
| Nitrogen (N) | 0.24 | 0.32 |
| Carbon (C) | — | 0.030 |
| Manganese (Mn) | — | 1.20 |
| Silicon (Si) | — | 0.80 |
| Copper (Cu) | — | 0.50 |
| Phosphorus (P) | — | 0.035 |
| Sulfur (S) | — | 0.020 |
Super Duplex 2507 Mechanical & Physical Properties
Super Duplex 2507's headline mechanical advantage is strength: a minimum 0.2% yield around 80 ksi (550 MPa), roughly twice that of annealed 316/316L, which lets instrumentation carry higher pressure at a given wall thickness. Hardness is held at or below 32 HRC, about 310 Brinell (HBW), the ceiling required for sour-service (NACE MR0175 / ISO 15156) hardware. Properties below are standard published values for annealed S32750, per the applicable standard and customizable to requirement.
| Property | Value (SI) | Value (US) |
|---|---|---|
| Yield strength (0.2%, min) | 550 MPa | 80 ksi |
| Tensile strength (min) | 795 MPa | 116 ksi |
| Elongation (min) | 15% | 15% |
| Hardness (max) | ≈ 310 HBW | 32 HRC |
| Density | 7.8 g/cm³ | 0.281 lb/in³ |
| Microstructure | ≈ 50/50 ferrite-austenite duplex | |
| Max continuous service temperature | ≈ 316 °C | ≈ 600 °F |
Super Duplex 2507 Corrosion Resistance, PREN & Chloride Behavior
The Pitting Resistance Equivalent Number for Super Duplex 2507 is above 42 (typically about 42.5 minimum), calculated as PREN = Cr + 3.3×Mo + 16×N. That is well above standard Duplex 2205 (≈35) and 316L (≈24), which is why 2507 resists pitting and crevice corrosion in warm chlorides and seawater where those grades fail. Its duplex structure also gives high resistance to chloride stress-corrosion cracking, the failure mode that limits austenitic stainless in hot chloride service. Continuous service is generally limited to about 600 °F (316 °C); above that range, sigma-phase and 475 °C embrittlement degrade toughness and corrosion resistance, so 2507 is not a high-temperature grade.
| Environment | Super Duplex 2507 behavior | Note |
|---|---|---|
| Warm seawater / chlorides | Excellent pitting & crevice resistance (PREN >42) | Out-performs 2205 and 316L |
| Chloride stress-corrosion cracking | High resistance | Duplex structure vs austenitic 316 |
| Sour service (wet H₂S) | Suitable to NACE MR0175 / ISO 15156 | Hardness controlled ≤ 32 HRC |
| Dilute organic / mild acids | Good | Verify concentration and temperature |
| Strong reducing acids | Limited | Consider a nickel alloy for these media |
When to Choose Super Duplex 2507 vs 2205, 254 SMO, AL-6XN & 316
Choose Super Duplex 2507 when a service is too aggressive for 316/316L or standard Duplex 2205 (S32205), warm chlorides, seawater, subsea, or sour gas, but a full nickel alloy would be over-specified for cost. Where the driver is even higher chloride temperature or acid resistance, the 254 SMO (6Mo) super-austenitic or AL-6XN alternatives may be the better fit. Use the comparison guides for a full side-by-side.
| Alloy | Approx. PREN | Choose when |
|---|---|---|
| 316 / 316L | ≈ 24 | General service, mild chlorides |
| Duplex 2205 | ≈ 35 | Moderate chlorides, higher strength than 316 |
| Super Duplex 2507 | > 42 | Warm chlorides, seawater, subsea, sour service |
| 254 SMO | ≈ 43 | Hot chlorides, higher acid resistance |
| AL-6XN | ≈ 47 | Severe chloride / seawater, maximum pitting margin |
Compare the full decisions in 2205 vs 2507, duplex vs super duplex, and 2507 vs 254 SMO vs AL-6XN, or see the full PREN comparison table.
Super Duplex 2507 Standards, Sour Service (NACE MR0175) & Material Traceability
Super Duplex 2507 instrumentation hardware from Crestflo is supplied to NACE MR0175 / ISO 15156 for sour H₂S service, with hardness controlled to the ≤ 32 HRC ceiling. Compression tube fittings are performance-qualified to ASTM F1387; instrumentation valves qualify to the applicable ASME B16.34 and API valve standards rather than F1387, which is a compression-fitting standard. The grade's product-form specifications cover ASTM A789 seamless tube, ASTM A790 pipe, ASTM A479 and A276 bar, and ASTM A182 F53 forgings; NORSOK M630 material data sheets and the related NORSOK M650 manufacturing-qualification standard apply in offshore work.
Crestflo is ISO 9001 / 14001 / 45001 and PED certified. Every part carries a heat/lot number for full traceability, and each order ships with an EN 10204 material test certificate, 3.1 as standard, 3.2 on request. In-house testing covers hydrostatic proof, burst and impulse, pneumatic, and positive material identification, with 100% seat and shell leak testing on manifolds; destructive testing is performed at ISO/IEC 17025-accredited laboratories, and third-party inspection is available on request. See material traceability & MTC for the full documentation package. Datasheets and CAD models are available to customers on request.
Super Duplex 2507 Instrumentation Forms: Tube Fittings, Valves & Tubing
Crestflo offers Super Duplex 2507 as finished instrumentation components, not mill plate, sheet, or structural bar. Available forms:
- Super Duplex 2507 tube fittings, single and double-ferrule compression tube fittings, end connections up to 2" (50 mm) OD, imperial and metric, F1387-qualified.
- Super Duplex 2507 instrumentation valves, needle, ball, check, manifold (2/3/5-way), and bleed valves, 1/16" to 1", threaded or tube-fitting ends, to ASME B16.34 / API.
- Super Duplex 2507 instrumentation tubing, seamless and welded instrumentation tubing to ASTM A789/A790.
These build on Crestflo's broader compression tube fittings program. Seamless pipe, plate, and mill bar are outside the US instrumentation scope; tubing is the supplied linear form.
Super Duplex 2507 Applications: Offshore, Seawater, Marine, Petrochemical & Sour Gas
Super Duplex 2507 applications cluster wherever warm chlorides, seawater, and wet H₂S defeat 316 and standard 2205. Typical uses for 2507 instrumentation hardware span offshore and subsea platforms, seawater and desalination service, marine and shipboard systems, petrochemical and chemical plants, sour oil and gas production and downstream refining, flue-gas desulphurisation (FGD), and hydrogen systems. Across these applications the driver is the same set of properties: a high chloride-pitting margin (PREN >42), strong resistance to chloride stress-corrosion cracking, and NACE-controlled hardness for sour duty, supplied as a finished fitting, valve, or tube rather than mill stock.
Super Duplex 2507 Price & Lead Time
Super Duplex 2507 is priced on a project basis, there is no fixed list price, because cost depends on the form, size, ferrule hardening, finish, and quantity. Crestflo quotes Super Duplex 2507 pricing on request against your bill of materials: request a quote for a firm price and lead time. As a super-duplex, 2507 costs more than 316 or 2205 but stays cost-competitive against a full nickel alloy for the same chloride or sour duty. Ready stock for standard items, made-to-order for specials, 6-8 week delivery.
Order Super Duplex 2507 Fittings & Valves: Request a Quote
Whether you are a distributor building a line card, an OEM needing a private-label program, an engineer sending a made-to-print drawing, or an end user specifying a sour-service assembly, Crestflo routes every inquiry to a quote, no dead ends. Super duplex grade 2507 fittings and valves are for sale through our RFQ model, no online cart or live pricing; to buy grade 2507 hardware, send your bill of materials and we quote by return. Ready stock for standard items, made-to-order for specials, 6-8 week delivery. To match a Swagelok®, Parker®, or Hy-Lok® part to a 2507 equivalent, request your cross-reference from our engineering team. Request a quote with your bill of materials to get started.
Why Crestflo: Your US-Serving Super Duplex 2507 Supplier & Manufacturer
As a US-serving manufacturer and supplier of Super Duplex 2507 instrumentation hardware, Crestflo is the instrumentation division of a four-decade-old, Government-of-India-recognized export house with a long Middle-East delivery track record, engineering depth applied to a focused US instrumentation line. Super Duplex 2507 hardware ships as F1387-qualified drop-in fittings and B16.34/API-qualified valves, in both imperial and metric, with heat-number traceability and EN 10204 MTC 3.1/3.2. Lead time is 6-8 weeks against the 20-plus weeks typical of the majors, with small MOQ and private-label options. Standard product is of Indian origin; US or European melt is available on request, with full material traceability, where domestic-melt or TAA requirements apply, handled transparently on origin & compliance. We Engineer Confidence.
Frequently Asked Questions About Super Duplex 2507
What is the equivalent of Super Duplex 2507?
Super Duplex 2507 is designated UNS S32750 and EN 1.4410 (X2CrNiMoN25-7-4); in forged and fitting form it maps to ASTM A182 F53. SAF™ 2507 is Alleima's trademark for the same grade. Zeron® 100 (UNS S32760) is a related but distinct super-duplex grade, not an exact equivalent of S32750.
Is 2507 a stainless steel?
Yes. Super Duplex 2507 is a super-duplex stainless steel with an approximately 50/50 ferrite-austenite structure, nominally 25% chromium, 7% nickel, 4% molybdenum, and controlled nitrogen, a stainless steel, not a nickel alloy.
Is there a difference between duplex and super duplex?
Yes. "Super" duplex grades such as 2507 have a PREN above 40 (versus about 35 for standard duplex 2205), giving markedly higher resistance to chloride pitting and crevice corrosion. See the full comparison in duplex vs super duplex.
What is the PREN of Super Duplex 2507?
The PREN of Super Duplex 2507 is above 42 (typically about 42.5 minimum), calculated as Cr + 3.3×Mo + 16×N, among the highest of the duplex family and well above 2205 (≈35) and 316L (≈24).
Is Super Duplex 2507 NACE compliant for sour service?
Yes. Crestflo supplies Super Duplex 2507 instrumentation hardware to NACE MR0175 / ISO 15156 for sour H₂S service, with hardness controlled to ≤ 32 HRC, heat-number traceability, and EN 10204 MTC 3.1/3.2. See NACE MR0175 / ISO 15156.
What is the maximum service temperature of Super Duplex 2507?
Continuous service is generally limited to about 600 °F (316 °C). Above that range, sigma-phase and 475 °C embrittlement degrade the grade's toughness and corrosion resistance, so 2507 is not intended for high-temperature service.
What forms of Super Duplex 2507 does Crestflo supply?
Crestflo supplies instrumentation tube fittings (up to 2" OD, single and double ferrule, F1387-qualified), instrumentation valves (1/16"–1", to ASME B16.34 / API), and instrumentation tubing, not mill plate, sheet, or structural bar.
Where is Crestflo's Super Duplex 2507 made and is it TAA compliant?
Standard Super Duplex 2507 product is of Indian origin; US or European melt is available on request, with full material traceability, where domestic-melt or TAA-eligible requirements apply. Origin and compliance are handled transparently on the origin & compliance page.
What is the lead time for Super Duplex 2507 fittings and valves?
Ready stock for standard items, made-to-order for specials, and 6-8 week delivery, against the 20-plus weeks typical of the majors, with small MOQ and private-label options. Request a quote for your BOM.
Related Super Duplex 2507 Resources
- All instrumentation fitting materials
- Super Duplex 2507 tube fittings
- Super Duplex 2507 instrumentation valves
- Super Duplex 2507 instrumentation tubing
- 2205 vs 2507 · duplex vs super duplex · 2507 vs 254 SMO vs AL-6XN
- Sour-service alloy selection · offshore & chloride selection
- Offshore & subsea instrumentation · petrochemical service · hydrogen service
- 6-8 week lead time · request a quote