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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UR 52N+, Industeel ArcelorMittal Super Duplex

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

UR 52N+ is the registered Industeel ArcelorMittal 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. The "UR" prefix stands for "Ugitech Reference" (legacy naming from the original Creusot-Loire Industeel works in France); the 52N+ suffix encodes the alloy class and the nitrogen-enhanced chemistry.

UR 52N+ 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. Industeel is a wholly-owned subsidiary of ArcelorMittal, with primary super duplex production from the Le Creusot mill in France and the Charleroi mill in Belgium. UR 52N+ is widely cited in oil and gas, seawater and desalination project specifications worldwide.

Industeel Trademark and Provenance

UR 52N+ is a registered trademark of Industeel Belgium SA / Industeel France SA, both wholly-owned subsidiaries of ArcelorMittal. The "UR" prefix dates back to the Ugitech / Creusot-Loire heritage of the Industeel mills, which were merged into the Usinor group in the 1990s and subsequently into ArcelorMittal. Industeel is one of the major European suppliers of duplex and super duplex stainless steel plate and forging stock, with particular strength in heavy plate (above 50 millimetres) for pressure vessel and offshore service.

UR 52N+ Composition (Industeel Datasheet)

Element	Industeel 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)	3.8	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 typical	41 to 43

Industeel's published datasheet for UR 52N+ sits at the centre of the UNS S32750 chemistry window, delivering consistent PREN of approximately 42.0 in mill heats.

UR 52N+ Product Range

Industeel supplies UR 52N+ in:

Heavy plate (Industeel's primary product line, including thicknesses above 100 millimetres)
Forging stock (round bar, ingot for downstream forging)
Strip and coil
Welding wire and consumables

Industeel's heavy plate strength is particularly relevant for offshore pressure vessels, subsea manifolds, and large-diameter pipe rolling. Mill capability covers single plates above 5 metres wide and 25 metres long in super duplex.

Standards UR 52N+ Meets

Standard	Designation
UNS	S32750
EN 10088-3	1.4410 / X2CrNiMoN25-7-4
ASTM A240 (plate)	UNS S32750
ASTM A479 (bar)	UNS S32750
ASTM A182 (forgings)	F53
NORSOK M-630	MDS D55, D57
NORSOK M-650	Manufacturer qualification (QTR)
NACE MR0175 / ISO 15156	Sour service compliance
EN 10222-5	Forgings for pressure purposes

TorqBolt Sourcing of UR 52N+

TorqBolt sources UR 52N+ from Industeel ArcelorMittal authorised distributors for project supplies that specifically call out the UR 52N+ trademark. Mill test certificates show the Industeel mill heat number and full traceability back to the Le Creusot or Charleroi mill of origin. UR 52N+ is particularly relevant for projects requiring heavy plate above 50 millimetres, where Industeel's mill capability is well suited. For projects that accept any UNS S32750-compliant material, TorqBolt also stocks UNS S32750 from other licensed mills (Sandvik SAF 2507, Outokumpu Avesta 2507) at the Mumbai warehouse.

UR 52N+ Frequently Asked Questions

What is UR 52N+?

UR 52N+ is the registered Industeel ArcelorMittal trademark for super duplex stainless steel with chemistry identical to UNS S32750 (American) and Werkstoff 1.4410 (European). Composition is 25Cr-7Ni-3.8Mo-0.27N nominal, with no intentional copper or tungsten. PREN is approximately 42.0. The grade is widely cited in offshore oil and gas project specifications.

Who owns the UR 52N+ trademark?

UR 52N+ is a registered trademark of Industeel Belgium SA and Industeel France SA, both wholly-owned subsidiaries of ArcelorMittal. The "UR" prefix is from the legacy Ugitech Reference / Creusot-Loire Industeel naming convention.

Is UR 52N+ the same as UNS S32750?

Yes. UR 52N+ is the Industeel 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.

What does the "UR" in UR 52N+ mean?

"UR" stands for Ugitech Reference, a legacy naming convention from the original Creusot-Loire Industeel works in France. The "52" relates to the alloy class number, "N" indicates nitrogen-enhanced chemistry, and "+" denotes the upgraded super duplex variant.

Where is UR 52N+ manufactured?

Industeel's primary super duplex mills are at Le Creusot in France and Charleroi in Belgium. Industeel is particularly strong in heavy plate (above 50 millimetres) and forging stock. All UR 52N+ carries the Industeel 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.

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

Functionally, yes. UR 52N+ (Industeel), SAF 2507 (Sandvik) 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 UR 52N+ by trademark may not accept material from other mills without engineering approval. Always check the project material requisition.

Which standards does UR 52N+ meet?

UNS S32750, EN 10088-3 (1.4410), ASTM A240 (plate), A479 (bar), A790 (pipe), A815 (fittings WP-S32750), A182 F53 (forgings), EN 10222-5 (forgings for pressure), 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).

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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