Super Duplex Round Bar
Super duplex 2507, Zeron 100 and Ferralium 255 round bar from Ø 8 mm to Ø 350 mm to ASTM A276 / A479 and NORSOK M-630 — 550 MPa yield, PREN above 40 and ASTM G48 testing at 50 °C.
What is Super Duplex Round Bar?
Super duplex round bar is a high-alloy duplex bar with a pitting resistance equivalent number above 40, giving it seawater and sour-service performance well beyond standard 2205. Steelco stocks UNS S32750 (2507 / F53), S32760 (Zeron 100 / F55) and S32550 (Ferralium 255) from Ø 8 mm to Ø 350 mm to ASTM A276 / A479 and NORSOK M-630, with 550 MPa minimum yield, 795 MPa minimum tensile and ASTM G48 Method A testing at 50 °C.
All grades we stock in super duplex round bar.
Click any grade for its full chemical composition, mechanical properties, equivalents and typical applications. Every grade ships with EN 10204 3.1 / 3.2 certification from our Mumbai stockyard.
Why Choose Super Duplex Round Bar
PREN above 40
Chromium 25 %, molybdenum 4 % and nitrogen 0.27 % give a PREN of 41–43 — resistant to pitting in warm seawater.
550 MPa minimum yield
More than twice the yield of 316L, allowing lighter shafting, bolting and manifold components offshore.
NORSOK M-630 compliant
Supplied to the North Sea material data sheets with ferrite count, hardness mapping and G48 corrosion testing.
Sour-service qualified
NACE MR0175 / ISO 15156 compliance with hardness limited to 32 HRC for downhole and wellhead trim.
Full bar conditions
Hot-rolled, peeled, cold-drawn, ground and forged bar, straightened to 0.5 mm/m for direct machining.
Cryogenic toughness
Charpy V-notch impact testing at –46 °C, and –101 °C on request for LNG and Arctic projects.
Technical Specifications
| Attribute | Details |
|---|---|
| Standards | ASTM A276 · A479 · A182 F53 / F55 · EN 10088-3 (1.4410 / 1.4501) · NORSOK M-630 |
| Grades Stocked | SDSS 2507 (S32750) · Zeron 100 (S32760) · Ferralium 255 (S32550) |
| Diameter Range | Ø 8 mm to Ø 350 mm (forged to Ø 600 mm on order) |
| Length | 3000 to 6000 mm; cut to length from 20 mm |
| Condition | Hot-rolled annealed & pickled · peeled · cold drawn · ground · forged |
| Yield Strength | 550 MPa minimum (80 ksi) |
| Tensile Strength | 795–1000 MPa (115–145 ksi) |
| Hardness | ≤ 310 HB · ≤ 32 HRC for NACE MR0175 service |
| PREN | ≥ 40 (typical 41–43) |
| Ferrite Content | 35–55 % verified per ASTM E562 |
| Testing | ASTM G48 Method A at 50 °C · ASTM A923 · Charpy at –46 °C · PMI · micro examination |
| Certification | EN 10204 3.1 standard · 3.2 with TÜV, SGS, BV, Lloyd's or DNV witness |
Grade availability by diameter band
| Grade | UNS | 8–25 mm | 25–75 mm | 75–150 mm | 150–250 mm | 250–350 mm |
|---|---|---|---|---|---|---|
| SDSS 2507 / F53 | S32750 | |||||
| Zeron 100 / F55 | S32760 | — | ||||
| Ferralium 255 | S32550 | — | — | |||
| Ground bar h9 | S32750 | — | — |
Note: Diameters above 350 mm, hollow bar and forged blanks are produced against order on a 4–8 week lead time.
Use our free metal weight calculator — bars, sheets, plates, pipes and sections.
Grade chemistry and mechanical properties supplied in super duplex round bar.
Chemical composition and mechanical properties are grade properties, not form properties — the same grade keeps the same chemistry whether it is supplied as sheet, plate or coil. The tables below list the specified limits for each grade we stock in super duplex round bar, tested and certified to ASTM A276 / A479 / A182 F53, F55. Values are weight percent (maximum unless a range is shown); mechanical values are minima in the annealed condition.
Chemical composition (weight %)
| Grade | C | Cr | Ni | Mo | N | Cu | Mn | P | W |
|---|---|---|---|---|---|---|---|---|---|
| Super Duplex 2507UNS S32750 | 0.030 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | 0.50 | 1.20 | 0.035 | — |
| Zeron 100UNS S32760 | 0.030 | 24.0–26.0 | 6.00–8.00 | 3.00–4.00 | 0.20–0.30 | 0.50–1.00 | 1.00 | — | 0.50–1.00 |
Balance iron. Single figures are maximum limits. Mill test certificates to EN 10204 3.1 are issued with every dispatch.
Mechanical properties (annealed, minimum)
| Grade | Tensile Strength (min) | Yield Strength (0.2%) | Elongation in 50 mm | Hardness (Rockwell C) | PREN |
|---|---|---|---|---|---|
| Super Duplex 2507 | 795 MPa (116 ksi) | 550 MPa (80 ksi) | 15% min | 32 max (NACE MR0175) | — |
| Zeron 100 | 750 MPa (109 ksi) | 550 MPa (80 ksi) | 25% min | — | 40 minimum |
Typical annealed values; actual results are stated on the heat-specific mill test certificate.
Application Sectors
Offshore Oil & Gas
Manifold bolting, valve stems and choke trim in sour and seawater service.
Subsea Systems
Connector bodies, hubs and clamp components to NORSOK M-630.
Desalination
High-pressure RO pump shafts, energy-recovery parts and brine piping supports.
Marine
Propulsion shafting, seawater lift pumps and firewater system parts.
Chemical Processing
Agitators and reactor internals in hot chloride and acid service.
Pulp & Paper
Bleach plant shafts and rolls resisting chloride dioxide attack.
Fasteners
Studbolts and nuts to ASTM A479 / A193 for offshore structural connections.
Power Generation
Seawater-cooled condenser components and FGD system hardware.
Cut, finished and certified to your drawing.
Material leaves our Mumbai facility finished to your specification — not as raw stock.
Why buy from Steelco.
Steelco Metal & Alloys is a Mumbai-based stockist, importer and exporter of stainless steel and nickel alloys, shipping certified material worldwide.
Quality & testing on every dispatch
- EN 10204 3.1 mill test certificate on every dispatch
- 3.2 certification with TÜV / SGS / BV / Lloyd's / IRS / IBR witness on request
- Positive Material Identification (PMI) with portable XRF / OES
- Dye-penetrant (DPT), ultrasonic (UT) and hydro testing on request
- NACE MR0175 / ISO 15156 compliance for sour service
- PED 2014/68/EU compliance for pressure equipment
- Heat-number stencilling and marking for full traceability
Deep ready stock
Super duplex bar held in Mumbai in 2507, Zeron 100 and Ferralium 255 from Ø 8 mm to Ø 350 mm — stocked sizes cut and dispatched within 48–96 hours with G48 and NACE documentation.
Mill-direct sourcing
Approved supply from Jindal, JSL, Outokumpu, Aperam, Acerinox, Sandvik and leading Japanese and Korean mills — every item traceable to a named producer.
Full certification
EN 10204 3.1 mill test certificate as standard, 3.2 with TÜV, SGS, BV, Lloyd's, IRS or IBR witness, plus PMI, DPT and UT reports on request.
On-time worldwide delivery
Regular export shipments to the GCC, Africa, Southeast Asia, Europe, Latin America and the USA via Nhava Sheva (JNPT), Mundra and Mumbai ports.
How your material is packed and shipped.
Every consignment leaves our Mumbai facility protected for transit and documented for customs, whether it moves by road within India or by sea to an overseas port.
Domestic & export packing
- Bundled in hessian with steel strapping, or in wooden cases
- VCI film and end caps on ground and machined bar
- Heat number stencilled and colour-coded on every bar
- Seaworthy crates with moisture barrier for export
Global shipments
- HS Code: 7222 (bar) · 7218 (semi-finished)
- FOB / CFR / CIF terms via Nhava Sheva (JNPT), Mundra and Mumbai ports
- Documentation: commercial invoice, packing list, MTC, bill of lading, COO, insurance
- Regular exports to the GCC, Africa, Southeast Asia, Europe, Latin America and the USA
Ready to price your requirement?
Share grade, size and quantity — our Mumbai desk responds with pricing, stock position and lead time, usually the same working day.
Frequently asked questions.
Answers to the questions our Mumbai desk is asked most often.
What is the difference between duplex 2205 and super duplex 2507?
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Super duplex 2507 carries more chromium, molybdenum and nitrogen, lifting the PREN from about 35 to above 40 and the minimum yield from 450 MPa to 550 MPa. 2507 is specified for warm seawater, high-chloride brine and severe sour service, where 2205 would pit.
Is Zeron 100 the same as 2507?
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Both are super duplex grades with PREN above 40, but Zeron 100 (S32760) adds copper and tungsten, which improve resistance in reducing acids and are often specified by North Sea operators. Steelco stocks both and dual certifies where the mill test allows.
What corrosion testing is done on super duplex bar?
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ASTM G48 Method A ferric chloride pitting test at 50 °C for 24 hours with no pitting and weight loss below 4.0 g/m², plus ASTM A923 Method B or C to confirm freedom from intermetallic phases.
Can super duplex bar be used in sour service?
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Yes, within NACE MR0175 / ISO 15156 limits. Hardness is controlled to 32 HRC maximum and the solution-annealed condition is verified, with hardness mapping reported on the certificate.
How should super duplex be machined?
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Use rigid setups, sharp carbide tooling, positive rake, lower cutting speeds than 316L and generous coolant. The alloy work-hardens quickly, so avoid dwelling and take consistent, deep cuts rather than light passes.