What is Super Duplex 2507?

Super Duplex 2507 (UNS S32750, Werkstoff 1.4410, X2CrNiMoN25-7-4) is a nitrogen-enhanced super duplex stainless steel with a balanced 50 to 50 austenite-ferrite microstructure. Nominal composition is 25Cr-7Ni-3.5Mo-0.3N with no intentional copper and no intentional tungsten. PREN above 41 qualifies the alloy as super duplex per NORSOK M-630. The alloy is solution annealed at 1040 to 1100 degrees Celsius and water quenched, with no precipitation hardening or aging step.

What is Super Duplex 2507 equivalent to?

Super Duplex 2507 is registered as UNS S32750 in the Unified Numbering System and as Werkstoff 1.4410 / X2CrNiMoN25-7-4 in EN 10088-3. Mill trademarks for the same UNS S32750 chemistry include SAF 2507 (Sandvik), UR 52N+ (Industeel ArcelorMittal) and Avesta 2507 (Outokumpu). It is covered by ASTM A479 (bar), A789 (tube), A790 (pipe), A815 (fittings, designation WP-S32750), A276 (shapes), and A182 grade F53 (forgings, flanges, forged fittings).

Is Super Duplex 2507 the same as Zeron 100?

No. Both are super duplex stainless steels with PREN above 40, but they are different alloys. Zeron 100 (UNS S32760) contains nominal 0.7 percent each of copper and tungsten. Super Duplex 2507 (UNS S32750) contains neither. The forging spec for 2507 is ASTM A182 F53; for Zeron 100 it is ASTM A182 F55. The two are not drop-in substitutes when a project specification names one or the other by UNS number.

What is the PREN of Super Duplex 2507?

Super Duplex 2507 has a PREN of approximately 41 to 43, calculated using the formula Cr + 3.3 times Mo + 16 times N. A typical mill heat with 25 percent chromium, 3.8 percent molybdenum, and 0.28 percent nitrogen yields PREN about 42. NORSOK M-630 requires PREN of 40 or above for super duplex classification.

What is the heat treatment of Super Duplex 2507?

Solution annealing at 1040 to 1100 degrees Celsius followed by rapid water quench. There is no precipitation hardening, no aging, no temper. The water quench must drive the material rapidly through the 600 to 1000 degrees Celsius band to avoid sigma-phase formation, which would cut Charpy toughness by 80 percent or more and compromise pitting resistance.

Is Super Duplex 2507 acceptable for sour service?

Yes, Super Duplex 2507 is qualified for sour service per NACE MR0175 and 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. TorqBolt supplies 2507 fasteners and forgings with NACE compliance certification on request.

Why does Super Duplex 2507 have no copper or tungsten?

The defining chemistry of UNS S32750 is 25Cr-7Ni-3.5Mo-0.3N with no intentional copper or tungsten addition. Adding either changes the alloy. Zeron 100 (S32760) adds about 0.7 percent each. Ferralium 255 (S32550) adds copper. Mixing these chemistries on a 2507 page is incorrect and creates a chimeric specification that does not exist in any mill datasheet or ASTM standard.

Which welding filler is correct for Super Duplex 2507?

ER2594 (overmatching, slightly higher PREN than the base) is the most common choice per AWS A5.9. ER2553 (matching) is also acceptable for less aggressive service. Both are nitrogen-enhanced fillers. Heat input should remain between about 0.5 and 2.5 kJ per millimetre, with interpass temperature below 150 degrees Celsius to avoid sigma-phase precipitation in the heat-affected zone.

What is Super Duplex 2507 used for?

Super Duplex 2507 is used in seawater service (velocities up to 6 metres per second), oil and gas downhole and surface (NACE MR0175 sour service), desalination plants (MSF, MED, RO), marine and subsea hardware (manifolds, christmas trees, jumpers), chemical processing (dilute HCl, H2SO4, HF), pulp and paper bleach plants (chlorine dioxide service), and flue gas desulfurization (WFGD absorber, quencher, outlet duct). Service temperature range is approximately minus 50 to 250 degrees Celsius continuous; sigma-phase risk above 300 degrees Celsius limits long-term high-temperature service.

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Super Duplex Stainless Steel

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SAF 2507, Sandvik Super Duplex Stainless Steel

Name: Super Duplex 2507 (UNS S32750 / EN 1.4410)
Brand: TorqBolt
SKU: TB-2507
Availability: InStock

SAF 2507 is the registered Sandvik trademark for the super duplex stainless steel chemistry registered as UNS S32750 in the American Unified Numbering System and Werkstoff 1.4410 (X2CrNiMoN25-7-4) in EN 10088-3. Sandvik (now part of Alleima following the 2022 spin-off) was the original developer of the 2507 chemistry in the early 1970s, and the SAF 2507 designation is widely cited in oil and gas, seawater and chemical processing project specifications worldwide.

The "SAF" prefix stands for "Sandvik Austenitic-Ferritic" and is used across Sandvik's duplex range (SAF 2205, SAF 2304, SAF 2507, SAF 2707 HD, SAF 3207 HD). The 2507 suffix encodes the nominal chemistry: 25 percent chromium, 0 percent intentional copper, 7 percent nickel. SAF 2507 carries the same chemistry, mechanical properties and corrosion resistance as UNS S32750 from any other producer; it is dual-certified to ASTM A479 / A790 / A815 / A182 F53 and EN 10088-3.

Sandvik Trademark and Provenance

SAF 2507 is a registered trademark of Sandvik AB (and now Alleima AB after the 2022 spin-off of Sandvik Materials Technology). Sandvik's mill in Sandviken, Sweden, holds the original development pedigree for the 2507 chemistry, which was introduced commercially in the early 1970s. The grade was the first super duplex stainless steel to be widely adopted in offshore oil and gas service, particularly on the Norwegian Continental Shelf.

SAF 2507 Composition (Sandvik Datasheet)

Element	Sandvik Typical %	UNS S32750 Window %
Carbon (C)	0.020 max	0.030 max
Chromium (Cr)	25.0	24.0 to 26.0
Nickel (Ni)	7.0	6.0 to 8.0
Molybdenum (Mo)	4.0	3.0 to 5.0
Nitrogen (N)	0.27	0.24 to 0.32
Copper (Cu)	0.50 max (residual, not intentional)	0.50 max (residual, not intentional)
PREN	42.5 typical	41 to 43

Sandvik's published datasheet for SAF 2507 sits at the centre of the UNS S32750 chemistry window, delivering consistent PREN of approximately 42.5 in mill heats.

SAF 2507 Product Range

Sandvik (now Alleima) supplies SAF 2507 in:

Seamless tube and pipe (Sandvikens primary product line)
Welded tube
Bar (round, hex, square)
Wire and welding wire (filler designation Sandvik 25.10.4.L for matching welding)
Strip and coil
Tube and pipe fittings (selected sizes)

Standards SAF 2507 Meets

Standard	Designation
UNS	S32750
EN 10088-3	1.4410 / X2CrNiMoN25-7-4
ASTM A479 (bar)	UNS S32750
ASTM A790 (pipe)	UNS S32750
ASTM A815 (fittings)	WP-S32750
ASTM A182 (forgings)	F53
NORSOK M-630	MDS D55, D57
NORSOK M-650	Manufacturer qualification (QTR)
NACE MR0175 / ISO 15156	Sour service compliance

TorqBolt Sourcing of SAF 2507

TorqBolt sources SAF 2507 from Sandvik / Alleima authorised distributors for project supplies that specifically call out the SAF 2507 trademark. Mill test certificates show the Sandvik mill heat number and full traceability back to the Sandviken or other licensed Sandvik mill of origin. For projects that accept any UNS S32750-compliant material, TorqBolt also stocks UNS S32750 from other licensed mills (Industeel UR 52N+, Outokumpu Avesta 2507) at the Mumbai warehouse.

SAF 2507 Frequently Asked Questions

What is SAF 2507?

SAF 2507 is the registered Sandvik trademark for super duplex stainless steel with chemistry identical to UNS S32750 (American) and Werkstoff 1.4410 (European). Composition is 25Cr-7Ni-4Mo-0.27N nominal, with no intentional copper or tungsten. PREN is approximately 42.5. The grade was developed by Sandvik in the early 1970s and is widely cited in oil and gas project specifications.

Who owns the SAF 2507 trademark?

SAF 2507 is a registered trademark of Sandvik AB. Following the 2022 spin-off of Sandvik Materials Technology, the trademark is now held by Alleima AB. The original mill in Sandviken, Sweden, retains development pedigree and continues to supply SAF 2507 worldwide.

Is SAF 2507 the same as UNS S32750?

Yes. SAF 2507 is the Sandvik trademark for the chemistry registered as UNS S32750 (American) and Werkstoff 1.4410 (European). The chemistry, mechanical properties and corrosion resistance are identical to UNS S32750 from other licensed mills. Mill test certificates show dual UNS / EN designation as standard.

What does the "SAF" in SAF 2507 mean?

SAF stands for Sandvik Austenitic-Ferritic, indicating the duplex (austenite-plus-ferrite) microstructure. The "2507" suffix encodes the nominal chemistry: 25 percent chromium, 0 percent intentional copper, 7 percent nickel. The SAF prefix is used across Sandvik's duplex grade range (SAF 2205, SAF 2304, SAF 2507, SAF 2707 HD, SAF 3207 HD).

Can SAF 2507 be substituted with UR 52N+ or Avesta 2507?

Functionally, yes. SAF 2507 (Sandvik), UR 52N+ (Industeel ArcelorMittal) and Avesta 2507 (Outokumpu) all certify to UNS S32750 / 1.4410. Mill chemistry, mechanical properties and corrosion resistance are equivalent. However, project specifications that name SAF 2507 by trademark may not accept material from other mills without engineering approval. Always check the project material requisition.

Which standards does SAF 2507 meet?

UNS S32750, EN 10088-3 (1.4410), ASTM A479 (bar), A790 (pipe), A815 (fittings WP-S32750), A182 F53 (forgings), NORSOK M-630 MDS D55 / D57, NORSOK M-650 (QTR), NACE MR0175 / ISO 15156-3 (sour service), API 6A and API 17D (wellhead and subsea).

Where is SAF 2507 manufactured?

The primary mill for SAF 2507 is in Sandviken, Sweden. Sandvik / Alleima also operates licensed production at additional sites worldwide. All SAF 2507 carries the Sandvik mill heat number and full traceability on the EN 10204 Type 3.1 mill test certificate. Type 3.2 third-party-witnessed certification is available on request.

Standards

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

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