Super duplex steel pipe earns its place where 316L and standard 2205 duplex start to pit. Seawater injection, desalination brine and chloride rich gas processing streams are typical examples. Grades UNS S32750 and S32760 handle this service with roughly 25% chromium, 7% nickel, high molybdenum and added nitrogen, giving a PREN of 40 or more. They are also strong. A minimum yield of 550 MPa lets engineers design thinner walls and lighter spools for offshore and onshore plants across the GCC and other export markets. Metinox Overseas supplies ASTM A790/A789 super duplex steel UNS S32750 / S32760 pipes and tubes - seamless pipes, welded pipes and ERW pipes, plus seamless and welded tubes as part of our pipes and tubes range.
Have a material specification or a line list ready? Send it with your grade, OD, wall, quantity and destination port, and our team will check it against ASTM A790 before quoting.
Table of Contents
- Super Duplex Steel Pipes & Tubes at a Glance
- Choosing Between UNS S32750 and S32760 Super Duplex Steel Pipes and Tubes
- ASTM A790 Super Duplex Steel UNS S32750 / S32760 Pipe Specification
- Types of Super Duplex Steel Pipe: Seamless, Welded and Rectangular
- Super Duplex Steel Pipe Dimensions and Schedule Chart (ASME B36.19M)
- Super Duplex Steel Pipes Chemical Composition (ASTM A790)
- Super Duplex Steel Pipe Mechanical Properties and Hardness Limits
- Physical Properties of Super Duplex Stainless Steel Pipe
- Equivalent Grades for Super Duplex Steel UNS S32750 and S32760 Pipes
- Duplex vs Super Duplex Steel Pipe: Which Grade to Specify
- Where Super Duplex Steel Pipes Are Used: Industry Applications
- Super Duplex Steel Pipe Price: What Affects Your Quotation
- Packing and Site Conditions for Super Duplex Steel Pipe Exports
- Request a Quotation for Super Duplex Steel Pipe
- Complete the System: Super Duplex Fittings and Flanges
- Super Duplex Steel Pipes & Tubes Exporter in India: Buyer FAQs
Super Duplex Steel Pipes & Tubes at a Glance
Super duplex stainless steel has a mixed microstructure of roughly equal austenite and ferrite. The term covers duplex grades with a Pitting Resistance Equivalent Number (PREN = %Cr + 3.3 %Mo + 16 %N) of 40 or higher. Two grades make up most orders:
- UNS S32750 (2507) is the most widely specified super duplex grade. It has the highest molybdenum allowance of the two and a minimum tensile strength of 800 MPa in pipe to ASTM A790.
- UNS S32760 (often sold as Zeron 100) adds copper and tungsten. Some operators specify it for firewater and seawater systems. Its heat treatment window and toughness requirements differ from S32750, so the two grades should not be treated as interchangeable without engineering approval.
For the lower alloyed family, see our duplex steel pipes. For a side by side comparison, read duplex vs super duplex stainless steel pipes.
Choosing Between UNS S32750 and S32760 Super Duplex Steel Pipes and Tubes
| Selection factor | UNS S32750 | UNS S32760 |
|---|---|---|
| Pipe and tube standards | ASTM A790 pipe, A789 tube | ASTM A790 pipe, A789 tube |
| Common names | 2507, SAF 2507 | Zeron 100 |
| EN number | 1.4410 | 1.4501 |
| Typical PREN | ≥ 41 | ≥ 40 (spec minimum often cited) |
| Copper and tungsten | Cu 0.50 max, no W requirement | Cu 0.50 to 1.00, W 0.50 to 1.00 |
| Minimum tensile, A790 pipe | 800 MPa (116 ksi) | 750 MPa (109 ksi) |
| Matching flange grade | ASTM A182 F53 | ASTM A182 F55 |
| Matching fitting grade | ASTM A815 WPS32750 | ASTM A815 WPS32760 |
| Typical choice | Process piping, heat exchangers, offshore topsides | Seawater, firewater, desalination piping |
ASTM A790 Super Duplex Steel UNS S32750 / S32760 Pipe Specification
| Parameter | Detail |
|---|---|
| Pipe standard | ASTM A790 / ASME SA790 |
| Tube standard | ASTM A789 / ASME SA789 |
| Welded large diameter pipe | ASTM A928 (electric fusion welded, with filler metal) |
| Grades | UNS S32750, UNS S32760 |
| Dimensional standard, pipe | ASME B36.19M (Sch 5S to 80S); ASME B36.10M for heavier walls such as Sch 160 and XXS |
| Tube wall tolerance | Per ASTM A1016, for example ±10% on average wall for seamless tube |
| Tube forms | Straight lengths, U-bent tubes, coiled instrument tubing |
| Size Range (Pipe) | Seamless: 1/8" to 12" NB | Welded / ERW: 1/2" to 24" NB | EFW (A928): 8" to 48" NB |
| Size Range (Tube) | 6.35 mm to 50.8 mm OD, 0.5 mm to 5 mm wall |
| Product forms | Seamless, welded, ERW type, EFW, rectangular and square hollow sections to drawing |
| End finish | Plain end, bevelled end (ASME B16.25), threaded |
| Length | Single random (5 to 7 m), double random (11 to 13 m), 5.8 m / 11.8 m for containers, cut to length |
| Heat treatment | Solution annealed and water quenched, per A790 / A789 temperature range |
| Certificate | EN 10204 3.1; 3.2 with third-party inspection on request |
Types of Super Duplex Steel Pipe: Seamless, Welded and Rectangular
Super Duplex Steel Seamless Pipes
Made from pierced billet or extruded hollow and then cold finished. Specify seamless for high pressure process lines, hydraulic and instrument service, and where the design code or operator specification excludes welded product.
Super Duplex Steel Seamless Tubes
ASTM A789 tubing is ordered by actual OD and wall instead of NPS. It is used in heat exchangers, umbilicals, and hydraulic and instrumentation lines. Coiled lengths and U-bent tubes are available for instrument tubing and exchanger bundles.
Super Duplex Steel EFW Pipe
Large-bore pipe from about 8" NB upward is electric fusion welded from plate with filler metal to ASTM A928, then solution annealed. It is the usual choice for seawater intake, firewater ring mains and desalination brine headers where seamless sizes run out.
Super Duplex Steel Welded Pipes & Tubes
Welded A790 pipe and A789 tube are formed from plate or strip and welded without filler. They are then solution annealed, which restores the phase balance in the weld zone. Welded pipe is usually more economical in larger diameters and thinner walls.
Super Duplex Steel Rectangular Pipes
Square and rectangular hollow sections are usually supplied to the buyer's drawing for structural and architectural use in marine settings.
Super Duplex Steel Pipe Dimensions and Schedule Chart (ASME B36.19M)
Outside diameter and wall thickness for common sizes. Wall thicknesses are nominal; tolerances follow ASTM A790 and ASME B36.19M.
| NPS | DN | OD (mm) | OD (in) | Sch 5S (mm) | Sch 10S | Sch 40S | Sch 80S |
|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 21.3 | 0.840 | 1.65 | 2.11 | 2.77 | 3.73 |
| 3/4 | 20 | 26.7 | 1.050 | 1.65 | 2.11 | 2.87 | 3.91 |
| 1 | 25 | 33.4 | 1.315 | 1.65 | 2.77 | 3.38 | 4.55 |
| 1 1/4 | 32 | 42.2 | 1.660 | 1.65 | 2.77 | 3.56 | 4.85 |
| 1 1/2 | 40 | 48.3 | 1.900 | 1.65 | 2.77 | 3.68 | 5.08 |
| 2 | 50 | 60.3 | 2.375 | 1.65 | 2.77 | 3.91 | 5.54 |
| 2 1/2 | 65 | 73.0 | 2.875 | 2.11 | 3.05 | 5.16 | 7.01 |
| 3 | 80 | 88.9 | 3.500 | 2.11 | 3.05 | 5.49 | 7.62 |
| 4 | 100 | 114.3 | 4.500 | 2.11 | 3.05 | 6.02 | 8.56 |
| 5 | 125 | 141.3 | 5.563 | 2.77 | 3.40 | 6.55 | 9.53 |
| 6 | 150 | 168.3 | 6.625 | 2.77 | 3.40 | 7.11 | 10.97 |
| 8 | 200 | 219.1 | 8.625 | 2.77 | 3.76 | 8.18 | 12.70 |
| 10 | 250 | 273.1 | 10.750 | 3.40 | 4.19 | 9.27 | 12.70 |
| 12 | 300 | 323.8 | 12.750 | 3.96 | 4.57 | 9.53 | 12.70 |
Weights: Super duplex has a density close to that of austenitic stainless, so our stainless steel pipe weight chart gives a fair estimate. Confirm final weights on the mill certificate. For schedule definitions, see the pipe schedule chart.
Need a size or schedule not listed? Send OD, wall and quantity and we will confirm stock and price within one working day. Request a Quote
Super Duplex Steel Pipes Chemical Composition (ASTM A790)
| Element | UNS S32750 | UNS S32760 |
|---|---|---|
| Carbon (C) | 0.030 | 0.030 |
| Manganese (Mn) | 1.20 | 1.00 |
| Phosphorus (P) | 0.035 | 0.030 |
| Sulphur (S) | 0.020 | 0.010 |
| Silicon (Si) | 0.80 | 1.00 |
| Nickel (Ni) | 6.0 to 8.0 | 6.0 to 8.0 |
| Chromium (Cr) | 24.0 to 26.0 | 24.0 to 26.0 |
| Molybdenum (Mo) | 3.0 to 5.0 | 3.0 to 4.0 |
| Nitrogen (N) | 0.24 to 0.32 | 0.20 to 0.30 |
| Tungsten (W) | - | 0.50 to 1.00 |
| Copper (Cu) | 0.50 | 0.50 to 1.00 |
Super Duplex Steel Pipe Mechanical Properties and Hardness Limits
| Property | S32750 pipe (A790) | S32750 tube (A789) | S32760 pipe (A790) | S32760 tube (A789) |
|---|---|---|---|---|
| Tensile strength, min | 800 MPa (116 ksi) | 800 MPa (116 ksi) | 750 MPa (109 ksi), max 895 MPa (130 ksi) | 750 MPa (109 ksi) |
| Yield strength (0.2% offset), min | 550 MPa (80 ksi) | 550 MPa (80 ksi) | 550 MPa (80 ksi) | 550 MPa (80 ksi) |
| Elongation in 50 mm, min | 15% | 15% | 25% | 25% |
| Hardness, max | 300 HBW / 32 HRC | 310 HBW / 32 HRC | 300 HBW | 300 HBW |
| Solution anneal temperature | 1025 to 1125 °C (1880 to 2060 °F) | 1025 to 1125 °C (1880 to 2060 °F) | 1100 to 1140 °C (2010 to 2085 °F) | 1100 to 1140 °C (2010 to 2085 °F) |
| Typical tube tests | - | Flattening, flaring, reverse bend for welded tube, hydrostatic or eddy current | - | Flattening, flaring, reverse bend for welded tube, hydrostatic or eddy current |
Physical Properties of Super Duplex Stainless Steel Pipe
| Property | Typical value |
|---|---|
| Density | 7.8 g/cm³ (0.28 lb/in³) |
| Modulus of elasticity at 20 °C | 200 GPa (29,000 ksi) |
| Thermal expansion, 20 to 100 °C | 13.0 µm/m·°C |
| Thermal conductivity at 20 °C | 14 to 15 W/m·K |
| Typical upper service temperature | About 250 to 300 °C, because of 475 °C embrittlement; check the design code |
Equivalent Grades for Super Duplex Steel UNS S32750 and S32760 Pipes
| UNS | EN number | EN name | Common names |
|---|---|---|---|
| S32750 | 1.4410 | X2CrNiMoN25-7-4 | 2507, SAF 2507 |
| S32760 | 1.4501 | X2CrNiMoCuWN25-7-4 | Zeron 100 |
Duplex vs Super Duplex Steel Pipe: Which Grade to Specify
| Property | Duplex 2205 (S32205) | Super duplex 2507 (S32750) | Super duplex (S32760) |
|---|---|---|---|
| Cr / Ni / Mo (%) | 22 / 5 / 3 | 25 / 7 / 4 | 25 / 7 / 3.5 + Cu, W |
| PREN (typical) | 34 to 36 | ≥ 40 | ≥ 40 |
| Yield strength, min (A790) | 450 MPa | 550 MPa | 550 MPa |
| Tensile strength, min (A790) | 655 MPa | 800 MPa | 750 MPa |
| Typical service | Brackish water, moderate chlorides | Seawater, brine, high-chloride process | Seawater, sour service, firewater |
Specify super duplex when chloride levels, temperature or seawater exposure push 2205 past its pitting limit. For milder service, our duplex steel pipes cost less and are available in the same size range.
Where Super Duplex Steel Pipes Are Used: Industry Applications
- Upstream oil and gas and offshore: produced water, seawater injection, topside process piping.
- Gas processing and LNG: chloride bearing cooling water and utility systems,plus heat exchanger and condenser tubing.
- Desalination and power and water: high pressure RO piping, brine lines, seawater intake and firewater.
- Refining and petrochemicals: overhead condenser piping with chlorides.
- Chemical processing and fertilizer: acid and chloride service.
Super Duplex Steel Pipe Price: What Affects Your Quotation
We do not publish a fixed price for super duplex. Nickel and molybdenum markets move often, and every enquiry differs in the following:
- Grade and heat (S32750 or S32760, and any mill preference)
- Seamless or welded, and the OD, wall and length
- Quantity, and whether the order comes from stock or a mill order
- Certification level (EN 10204 3.1 or 3.2)
- Third party inspection, PMI and extra tests such as A923, impact, HIC or SSC
- Incoterm and destination port
For a fast quotation, send: grade, standard, OD, wall, length, quantity, end finish, certification, inspection requirements, destination port and required date.
Packing and Site Conditions for Super Duplex Steel Pipe Exports
- Plastic end caps on plain ends, bevel protectors on bevelled ends
- Bundled with non metallic strapping, or packed in wooden boxes for small sizes
- Kept apart from carbon steel during handling and storage, which prevents iron contamination and surface rust staining
- Covered laydown in hot, humid or sandy sites. Coastal chloride deposits should be washed off before fabrication.
Request a Quotation for Super Duplex Steel Pipe
Send your enquiry with the grade, size, quantity and destination port, and attach any operator or project material specification. We will reply with a quotation and confirm the lead time.
Request a QuoteComplete the System: Super Duplex Fittings and Flanges
- Super duplex pipe fittings (ASTM A815 WPS32750 / WPS32760)
- ASTM A815 S32750 fittings and ASTM A815 S32760 fittings
- Duplex and super duplex flanges
- Super duplex 2507 flanges (F53) and super duplex 32760 Zeron 100 flanges (F55)
- Tubing: UNS S32750 tubes and UNS S32760 tubes
Super Duplex Steel Pipes & Tubes Exporter in India: Buyer FAQs
Yes, within limits. NACE MR0175 / ISO 15156-3 allows solution annealed super duplex in sour service within set limits on temperature, H2S partial pressure, chloride and hardness. Check your operating envelope against the standard and your operator's specification.
Both have about 25% chromium and 7% nickel. S32760 adds 0.5 to 1.0% copper and 0.5 to 1.0% tungsten, and has a slightly lower minimum tensile strength in ASTM A790. Matching flanges are F53 for S32750 and F55 for S32760.
ASTM A790 covers pipe, which is ordered by NPS and schedule. Large welded pipe made with filler metal is covered by ASTM A928. Tubing ordered by actual OD and wall is covered separately by ASTM A789.
Lengths are cut to your order. 5.8 m and 11.8 m lengths fit 20 ft and 40 ft containers.
Send the grade, standard, OD, wall, length, quantity, end finish, certification, inspection requirements, destination port and required date.
Choose seamless for high-pressure process, hydraulic and sour service lines, or where your operator specification excludes welded product. Welded pipe to ASTM A790 or A928 is the economical choice for large-bore seawater, firewater and cooling water lines, usually from 8" NB upward.
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