Super Duplex 2507 Tube Fittings (UNS S32750 / W.Nr. 1.4410, 25Cr Super Duplex Stainless)
Super Duplex 2507 tube fittings are mechanical-grip compression fittings machined from UNS S32750 super-duplex stainless steel, a nominal 25Cr-7Ni-4Mo-N grade with a two-phase austenite-plus-ferrite microstructure and a Pitting Resistance Equivalent Number above 42. One or two ferrules swage onto the tube's outside diameter for a leak-tight, gas-tight seal and a firm mechanical grip. That combination is exactly why engineers reach for a 2507 fitting on offshore topside and subsea instrument lines, seawater cooling, desalination, and sour (H₂S) service, the warm-chloride duty where 316 pits and stress-corrosion-cracks, and where even standard Duplex 2205 is under-alloyed. Crestflo carries these fittings from 1/8-inch through 2-inch (50 mm) tube OD, in both single and double (twin) ferrule versions, imperial and metric. They are qualified to ASTM F1387 and offered to NACE MR0175 / ISO 15156 for sour service. Standard items ship from ready stock; specials are built to order, with delivery running 6-8 weeks. Request a quote to price out your configuration.
SAF™ 2507 is a trademark of Alleima (formerly Sandvik); Zeron® 100 is a trademark of Rolled Alloys. Crestflo supplies UNS S32750 and UNS S32760 to standard chemistry and is not affiliated with or endorsed by either company.
What Super Duplex 2507 Compression Tube Fittings Are
A Super Duplex 2507 compression tube fitting is built for fluid-system instrumentation work: a body, a nut, and one or two ferrules that bite onto the tube's outer diameter as the nut is pulled up. The joint comes apart and goes back together without losing integrity. No flaring, no welding, no elastomer seal sitting in the leak path. The seal is metal-to-metal, so the service window comes from the alloy itself, not from an O-ring giving out first.
Scope matters here. These are instrumentation compression tube fittings in S32750 super-duplex stainless, not mill plate, not structural bar, not plumbing pipe fittings, and not electrical wire ferrules. They land on small-bore instrument tubing for transmitters, analyzers, sample lines, chemical-injection systems, and process taps on platforms, subsea hardware, and seawater systems, anywhere warm chlorides, seawater, or wet H₂S push austenitic stainless out of the running.
Also Known As: UNS S32750, 1.4410, Alloy 2507, SD2507 & F53
Buyers and specifiers write this grade several ways, but they all point to the same 25Cr super-duplex stainless. On drawings and in material call-outs it shows up as Super Duplex 2507, 2507 super duplex, Alloy 2507, Duplex 2507, SD2507, and super duplex stainless steel 2507. Its formal designations are UNS S32750 and EN / Werkstoff 1.4410 (EN steel name X2CrNiMoN25-7-4); in forged and fitting form it maps to ASTM A182 Grade F53. SAF™ 2507 is Alleima's trade name for the same S32750 grade, referenced here for identification only. Zeron® 100 (UNS S32760) is a closely related 25Cr super-duplex grade that Crestflo also supplies, distinct in UNS number and not an exact equivalent of S32750, but specified for the same warm-chloride and seawater duty.
| Designation type | Value |
|---|---|
| Common names | Super Duplex 2507, Alloy 2507, Duplex 2507, SD2507 |
| UNS number | 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) |
| Related but distinct grade | Zeron® 100 (UNS S32760) |
Because these names all point to the same product, asking for "Alloy 2507 tube fittings," "2507 ferrule fittings," or "UNS S32750 tube fittings" gets you exactly what's described on this page. The terms are interchangeable.
Why Choose Super Duplex 2507 for Instrumentation Tube Fittings
Super Duplex 2507 is a nitrogen-enhanced super-duplex stainless, nominally 25% chromium, 7% nickel, 4% molybdenum, with controlled nitrogen, and its roughly 50/50 ferrite-austenite structure is what makes it the right pick for a fitting in warm chloride service. Two properties drive the choice. First, corrosion: with a PREN above 42, 2507 resists chloride pitting and crevice corrosion well beyond 316L (≈24) or standard Duplex 2205 (≈35), and its duplex structure gives it strong immunity to chloride stress-corrosion cracking, the failure mode that limits austenitic stainless in seawater and hot brine. Second, strength: the grade's minimum yield is roughly double that of annealed 316/316L, so a fitting body and ferrule hold their rated pressure with less wall, which matters on compact offshore manifolds and subsea assemblies.
One limit to respect when you specify 2507 for a fitting: continuous service is generally capped at 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 a high-temperature alloy, keep it in the warm-chloride, seawater, and sour-service window where it excels.
For the full metallurgical picture, composition, mechanical and physical properties, phase behavior, and corrosion-by-media data, see the Super Duplex 2507 grade page. The reference composition is summarized below for convenience when writing specs. Values follow the applicable ASTM/EN specification and can be customized 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 |
The high chromium, molybdenum, and nitrogen together drive the pitting resistance, while balanced nickel keeps the ferrite-austenite ratio near 50/50. The key strength and corrosion figures that make 2507 a fitting-grade super duplex are summarized here.
| 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 |
| PREN (Cr + 3.3×Mo + 16×N) | > 42 (typically ≈ 42.5 min) | |
| Max continuous service temperature | ≈ 316 °C | ≈ 600 °F |
For the head-to-head against standard duplex, see 2205 vs 2507 and duplex vs super duplex; for the lower-alloy option, see Duplex 2205.
Super Duplex 2507 Tube Fitting Sizes (1/8-inch to 2-inch OD): Imperial & Metric
Crestflo machines S32750 tube fittings in both imperial fractional and metric tube-OD series, with end connections up to 2-inch (50 mm) OD. The chart below covers the standard range. Working pressure for any given fitting depends on size, wall thickness, and temperature; it comes from standard tube-fitting pressure data for the tube OD and wall, following ASTM/ASME practice, and the exact rated pressure for your configuration is confirmed on the quotation. Super duplex earns part of its keep here, its high yield strength lets a given wall carry more pressure than a 316 fitting of the same geometry. Values follow the applicable standard and can be customized to requirement.
| Tube OD, imperial | Tube OD, metric | Availability |
|---|---|---|
| 1/8", 1/4", 3/8", 1/2" | 6 mm, 8 mm, 10 mm, 12 mm | Standard range |
| 5/8", 3/4", 1" | 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 25 mm | Standard range |
| up to 2" (50 mm) | up to 50 mm | Made-to-order |
Super Duplex 2507 Tube Fitting End & Thread Connections: NPT, BSPP, JIC & Weld
Fittings come with tube-OD compression ends, tapered or parallel threads, or weld ends. All are available in national, international, and custom thread types.
| End type | Thread / connection standards |
|---|---|
| Tube-OD (compression) | Fractional inch and metric OD |
| Male / female tapered thread | NPT, NPTF, BSPT |
| Male / female parallel thread | BSPP, ISO parallel, SAE ORB |
| Flare / port | JIC 37°, SAE ORB |
| Weld end | Socket-weld, butt-weld, orbital |
Single vs Double Ferrule & Hardened vs Non-Hardened Options
S32750 fittings come in single-ferrule and double (twin) ferrule designs, with hardened or non-hardened ferrules supplied depending on the job. This choice shapes gripping action, vibration resistance, and how many times a fitting can be reassembled. Super duplex is already a high-strength, relatively hard base alloy, so ferrule selection and surface treatment are worth getting right, Crestflo applies anti-galling measures such as silver plating on request where repeated make-up or high torque is expected.
| Configuration | Description | When it is used |
|---|---|---|
| Double (twin) ferrule | Front ferrule seals, back ferrule grips | General instrumentation, vibration, gas-tight service |
| Single ferrule | One ferrule seals and grips | Simpler assemblies, certain hydraulic and OEM designs |
| Hardened ferrule | Case-hardened grip surface | Harder tube materials, maximum hold |
| Non-hardened ferrule | Softer grip surface | Thin-wall or softer tubing |
For guidance on making the right choice, see single vs double vs ferrule-less fittings and hardened vs non-hardened ferrules. Replacement nuts and ferrules are stocked separately, and so are single-ferrule fittings and double-ferrule fittings.
Available Super Duplex 2507 Fitting Shapes & Connectors
S32750 covers the full geometry range, so you can build a complete instrument run in a single material:
- Union, elbow, tee, cross, and reducer fittings
- Male connectors, female connectors, and adapters for joining mismatched threads
- Bulkhead unions, port connectors, caps, and plugs for sealing off unused lines
- Weld connectors (socket, butt, and orbital)
Super Duplex 2507 comes in related fitting families too, including 37° JIC flare fittings and DIN 2353 bite-type fittings, all combinable within the same instrument tubing system. For the full geometry range and ferrule design, start at the tube-fittings product hub.
Corrosion & Service: Seawater, Warm Chlorides, Subsea & Sour (H₂S) Duty
What a fitting actually sees in service is the whole reason to specify Super Duplex 2507 over 316 or 2205. The table below sums up how S32750 behaves against the media that drive fitting selection. These are the grade's published, standard-referenced characteristics, not a per-fitting rating; the corrosion allowance and suitability for a specific stream stay the specifier's call.
| Media / service | Super Duplex 2507 behavior | Note |
|---|---|---|
| Warm seawater / chlorides | Excellent | PREN >42, out-performs 2205 and 316L on pitting & crevice attack |
| Chloride stress-corrosion cracking | High resistance | Duplex structure vs austenitic 316, the key offshore advantage |
| Subsea / offshore topside | Excellent | High strength plus chloride resistance in a single fitting material |
| 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 |
| Above ≈ 600 °F (316 °C) | Not recommended | Sigma-phase / 475 °C embrittlement, 2507 is not a high-temp grade |
Where the driver is even higher chloride temperature or acid resistance, a super-austenitic grade may be the better fit, compare 2507 vs 254 SMO vs AL-6XN. Where it is strongly reducing or oxidizing acid service, a nickel alloy is usually the call.
Standards, Testing & NACE MR0175 Sour-Service Compliance
Crestflo qualifies its compression tube fittings to ASTM F1387, the performance standard for mechanically attached fittings. That's the basis for the dimensional interchange and mechanical-integrity claims below. For sour service, S32750 fittings are offered to NACE MR0175 / ISO 15156 with hardness controlled to the ≤ 32 HRC ceiling the standard requires. The grade's product-form specifications cover ASTM A789 (seamless tube), A815 (wrought fittings), A182 F53 (forgings), and A479/A276 (bar); we hold the standard approvals that apply to instrumentation tube fittings.
| Standard / certification | Scope | Applies here |
|---|---|---|
| ASTM F1387 | Mechanically attached fitting performance | Yes |
| NACE MR0175 / ISO 15156 | Sour-service materials (≤ 32 HRC) | Yes |
| EN 10204 MTC 3.1 / 3.2 | Material test certification | Yes |
| ASTM A789 / A815 / A182 F53 | Super-duplex tube, wrought-fitting & forging feedstock | As applicable |
| ISO 9001 / 14001 / 45001 & PED | Quality, environmental, safety, pressure | Certified |
These fittings go through a wide battery of tests. Hydraulic proof, burst, and impulse come first. Then pneumatic, flexure-fatigue, rotary-flex, vibration, and thermal-cycling work, plus pull-out and vacuum checks. Positive material identification (PMI) confirms the alloy on every piece, important on a super-duplex, where chemistry controls the phase balance and the corrosion performance. NDT is standard and done in-house. Destructive testing goes out to labs accredited under ISO/IEC 17025. Third-party inspection is available on request.
Material Traceability & Certification
Every S32750 part is marked with its own heat/lot number. Each shipment comes standard with an EN 10204 MTC 3.1 certificate, and 3.2 is available on request. PMI confirms grade at the part level, every time. That documentation backs solid audit trails for offshore, subsea, seawater, and sour-service work, the jobs where a mis-specified or under-alloyed fitting is not a small problem. Datasheets and CAD models are available to customers on request.
Drop-In Interchange with Swagelok, Parker & Hy-Lok
Crestflo S32750 fittings are built as dimensional interchange / equivalent fittings for the major instrumentation brands, and that claim rests on ASTM F1387 performance qualification, not on marketing language. These aren't "compatible" or "intermix" parts. Brand names such as Swagelok®, Parker®, and Hy-Lok® remain trademarks of their respective owners, and Crestflo is not affiliated with them; the interchange is strictly dimensional. We don't publish a part-number table. Instead, we prepare interchange references per project: request your cross-reference, and our engineering team will map your existing part numbers to Crestflo Super Duplex 2507 equivalents.
Origin & US-Serving Positioning
Crestflo manufactures for the US market. Standard product comes from India; US or European melt is available on request, with full material traceability. Parts are engineered as US drop-in replacements and ship in 6-8 weeks. TAA/DFARS and domestic-melt requirements are handled straight, no hedging, on our US-origin compliance page. If a project calls for a specific melt origin, just specify it on the RFQ.
Applications & Industries for Super Duplex 2507 Tube Fittings
Super Duplex 2507 fittings show up wherever warm chlorides, seawater, and wet H₂S defeat 316 and standard 2205:
- Offshore and subsea oil & gas, topside instrument and hydraulic lines, subsea control hardware, and produced-water systems, where chloride SCC immunity and high strength both count.
- Seawater cooling and desalination, seawater lift, cooling, and RO systems where pitting and crevice resistance decide service life.
- Marine and shipboard systems, high-chloride instrument and sample lines.
- Sour oil and gas, H₂S-bearing instrumentation qualified to NACE MR0175 / ISO 15156, hardness controlled.
- Petrochemical and chemical, chloride-bearing process and sampling lines, including flue-gas desulphurisation.
Crestflo supplies S32750 instrumentation components into offshore and subsea and oil and gas applications, among others.
Why Crestflo for Super Duplex 2507 Tube Fittings
Crestflo operates as the instrumentation division of an export house with four decades behind it and formal recognition from the Government of India. That parent company has a proven delivery record across the Middle East. Its backing grounds a new, focused instrumentation brand built on a handful of clear advantages:
- Lead time of 6-8 weeks versus 20+ weeks typical of the majors.
- ASTM F1387 drop-in interchange proof that mill and trading suppliers rarely publish.
- Small MOQ and private label for distributors and OEMs.
- Both imperial and metric on every fitting, single or double ferrule, hardened or non-hardened.
- Heat-number marking plus MTC 3.1/3.2 on every order, PMI-confirmed.
- Cost-competitive after US duties and tariffs, ISO 9001 / 14001 / 45001 & PED certified.
We Engineer Confidence.
Request a Quote for Super Duplex 2507 Fittings
Give us the details: size, shape, ferrule, thread, and quantity. We'll price it out and get your order scheduled:
- Request a quote, the fastest path to pricing and lead time.
- Request a sample for qualification.
- Become a distributor for line-card and stocking programs.
Datasheets and CAD models are available to customers on request. Reach Crestflo's US sales desk at sales@crestflousa.com or +1 346 594 9005 (Houston, TX). Round out your system with the related Super Duplex 2507 instrumentation valves and Super Duplex 2507 tubing, and serve the corrosion-critical lines in offshore and subsea and oil and gas.
Frequently Asked Questions
Are Alloy 2507 and Super Duplex 2507 the same?
Yes. "Alloy 2507," "Duplex 2507," "SD2507," and "Super Duplex 2507" all point to the same material: UNS S32750, also listed as EN / Werkstoff 1.4410 (X2CrNiMoN25-7-4), a 25Cr-7Ni-4Mo-N super-duplex stainless steel. In forged and fitting form it maps to ASTM A182 F53. SAF™ 2507 is Alleima's trade name for the same grade. Zeron® 100 (UNS S32760) is a closely related super-duplex grade that Crestflo also supplies, but it is a distinct UNS number, not an exact equivalent of S32750.
Why use Super Duplex 2507 tube fittings instead of 316 or 2205?
Super Duplex 2507 is the better choice where the stream is warm seawater, high in chlorides, subsea, or sour (H₂S). With a PREN above 42, it resists pitting and crevice corrosion well beyond 316L (≈24) and standard Duplex 2205 (≈35), and its duplex structure gives strong immunity to the chloride stress-corrosion cracking that limits austenitic stainless offshore. Its yield strength is roughly double that of 316, so thinner walls hold the same pressure. For milder chloride service, 2205 may be enough; 2507 is the step up when 316 or 2205 is under-alloyed.
How much do Super Duplex 2507 tube fittings cost?
As a super-duplex, 2507 fittings cost more than 316 or 2205, and the price shifts with size, shape, ferrule type, and quantity ordered. Crestflo stays cost-competitive against a full nickel alloy for the same chloride or sour duty, and against the majors after US duties and tariffs, but it quotes per configuration. There's no live pricing posted anywhere. Request a quote to get a firm number.
What are Super Duplex 2507 tube fittings used for?
They handle corrosion-critical instrumentation lines wherever warm chlorides, seawater, or H₂S rule out 316: offshore topside and subsea oil-and-gas systems, seawater cooling and desalination, marine and shipboard lines, sour oil and gas service, and chloride-bearing petrochemical process and sampling lines. In instrumentation terms, that's the fittings on seawater, chloride, and sour analyzer, sampling, and process runs.
Are Crestflo Super Duplex 2507 fittings NACE-compliant?
Yes. Crestflo offers S32750 fittings to NACE MR0175 / ISO 15156 for sour H₂S service, with hardness controlled to the ≤ 32 HRC ceiling and material traceability backing project qualification. Confirm the certified hardness and environmental limits in the standard against your application.
Do they interchange with Swagelok, Parker, or Hy-Lok fittings?
They're built as dimensional interchange and equivalent fittings, with performance backed by ASTM F1387 qualification. We don't call them "compatible" or "intermix," and every brand name mentioned belongs to its respective owner; Crestflo is not affiliated. Send us your cross-reference request and we'll map your part numbers.
What sizes are available?
Tube-OD sizes run from 1/8-inch up to 2-inch (50 mm), covering both imperial fractional and metric series, in single or double ferrule. Standard sizes span 1/8" to 1" and 6 mm to 25 mm; anything larger is made to order.
What is the maximum service temperature for a Super Duplex 2507 fitting?
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, keep it in the warm-chloride, seawater, and sour-service window.
Are single and double ferrule versions both offered?
Yes. Both single-ferrule and double (twin) ferrule designs are available, with hardened or non-hardened ferrules supplied depending on what's required. Because super duplex is a high-strength, relatively hard base alloy, anti-galling measures such as silver plating are offered on request where repeated make-up or high torque is expected.
What material certification comes with the fittings?
Standard practice is an EN 10204 MTC 3.1 certificate, though 3.2 is available on request. Every part gets a heat/lot number stamped on it, and PMI confirms the alloy is genuinely S32750, which matters on a super-duplex, where chemistry controls the phase balance and corrosion performance.
Are these made in the USA?
Crestflo manufactures for the US market. Standard product comes from India, though US or European melt is available on request, complete with full material traceability. It's engineered for a US drop-in fit and ships in 6-8 weeks. For TAA and origin specifics, see the US-origin compliance page.
What thread and end connections are available?
Tube-OD compression ends come standard, alongside NPT, NPTF, BSPT, BSPP, and ISO parallel threads. JIC 37° and SAE ORB fittings round out the lineup, and weld ends are available in socket, butt, and orbital styles. National, international, or custom thread, they're all supported.
What is the minimum order and lead time?
Small minimum order quantities apply, and lead time for US orders runs 6 to 8 weeks. Standard items ship from ready stock; specials are made to order. Private-label and custom or made-to-print options are also available.