UNS S32760|1.4501|S32760 Seamless Super Duplex Steel Tube
Featuring an exceptionally high Pitting Resistance Equivalent Number (PREN ≥ 41), our S32760 tubes provide superior resistance to pitting and crevice corrosion in aggressive chloride environments. The addition of tungsten and copper enhances its stability in both organic and inorganic acids, making it a superior choice for sour gas (H2S) services, desalination, and subsea infrastructure. Through advanced cold-drawing and precise solution annealing, XinZhe ensures every tube maintains optimal phase balance and unmatched mechanical strength, even in the most demanding offshore applications.
PREN =%Cr + 3.3X(%Mo + 0.5X%W) + 16X%N≥ 41
What Is a Seamless Super Duplex S32760 Tube?
UNS S32760, widely known as Zeron 100, is a super duplex stainless steel with a balanced 50:50 austenite-ferrite microstructure. The combination of high chromium, molybdenum, nitrogen and a deliberate tungsten addition gives it a PREN above 40, making it a standard choice for subsea manifolds, seawater systems and sour oil and gas service where both strength and corrosion resistance are critical.
High-Performance Tubing for Extreme Corrosion and High-Pressure Environments
A Seamless Super Duplex Steel S32760 tube is a high-alloy stainless steel tube specifically engineered for extremely aggressive industrial environments. These tubes are produced through hot piercing and cold drawing processes from a solid billet, creating a fully homogeneous metallurgical structure without weld seams.
Compared with welded pipes, seamless S32760 tubing eliminates the risk of weld-line corrosion and heat-affected zones, providing superior structural reliability in critical applications.
The alloy is commonly designated as UNS S32760, also known as F55, a premium grade within the Super Duplex Stainless Steel family.
Super duplex steels are characterized by a balanced 50/50 austenitic–ferritic microstructure, combining the corrosion resistance of austenitic stainless steels with the mechanical strength of ferritic grades.
The chemical composition of S32760 includes elevated levels of:
and additional alloying elements such as:
This optimized chemistry results in a Pitting Resistance Equivalent Number (PREN) greater than 40, placing S32760 among the most corrosion-resistant stainless steels available for industrial use.
Key Features and Technical Advantages
Super Duplex S32760 tubing provides exceptional resistance to localized corrosion mechanisms such as pitting and crevice corrosion. It performs reliably in high-chloride environments and sour gas conditions where conventional grades like 316L stainless steel or even Duplex 2205 stainless steel may fail.
S32760 offers approximately twice the yield strength of standard austenitic stainless steels, allowing engineers to design thinner wall structures while maintaining high pressure capability. This property significantly reduces structural weight in offshore and subsea installations.
The ferritic phase of the duplex microstructure provides strong resistance to chloride-induced stress corrosion cracking (SCC), making the alloy particularly suitable for seawater and desalination systems.
Outstanding Pitting and Crevice Corrosion Resistance
Super Duplex S32760 tubing provides exceptional resistance to localized corrosion mechanisms such as pitting and crevice corrosion. It performs reliably in high-chloride environments and sour gas conditions where conventional grades like 316L stainless steel or even Duplex 2205 stainless steel may fail.
High Mechanical Strength
S32760 offers approximately twice the yield strength of standard austenitic stainless steels, allowing engineers to design thinner wall structures while maintaining high pressure capability. This property significantly reduces structural weight in offshore and subsea installations.
Excellent Stress Corrosion Cracking Resistance
The ferritic phase of the duplex microstructure provides strong resistance to chloride-induced stress corrosion cracking (SCC), making the alloy particularly suitable for seawater and desalination systems.
Enhanced Fatigue and Pressure Performance
The seamless manufacturing process eliminates heat-affected zones, ensuring uniform burst strength and improved fatigue resistance under cyclic pressure conditions.
Reliable Low-Temperature Toughness
S32760 maintains excellent impact toughness even at sub-zero temperatures, allowing it to perform reliably in Arctic offshore projects and cryogenic service environments.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Super Duplex Steel UNS S32760.
The composition of UNS S32760 is carefully balanced to achieve its superior corrosion resistance and high strength.
| Grade | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu | Others |
| 31803 | ≤0.03 | ≤2.00 | ≤0.03 | ≤0.02 | ≤1.00 | 4.50-6.50 | 21.00-23.00 | 2.50-3.50 | 0.08-0.20 | … | … |
| 32205 | ≤0.03 | ≤2.00 | ≤0.03 | ≤0.02 | ≤1.00 | 4.50-6.50 | 22.00-23.00 | 3.00-3.50 | 0.14-0.20 | … | … |
| 31500 | ≤0.03 | 1.20-2.00 | ≤0.03 | ≤0.03 | 1.40-2.00 | 4.3-5.2 | 18.00-19.00 | 2.50-3.00 | 0.05-0.10 | … | … |
| 32550 | ≤0.04 | ≤1.50 | ≤0.04 | ≤0.03 | ≤1.00 | 4.50-6.50 | 24.00-27.00 | 2.90-3.90 | 0.10-0.25 | 1.50-2.50 | … |
| 32750 | ≤0.03 | ≤1.20 | ≤0.035 | ≤0.02 | ≤0.80 | 6.00-8.00 | 24.00-26.00 | 3.00-5.00 | 0.24-0.32 | ≤0.50 | … |
| 32760 | ≤0.03 | ≤1.00 | ≤0.030 | ≤0.01 | ≤1.00 | 6.00-8.00 | 24.00-26.00 | 3.00-4.00 | 0.20-0.30 | 0.50-1.00 | W 0.50 -1.00 |
| 32950 | ≤0.03 | ≤2.00 | ≤0.035 | ≤0.01 | ≤0.60 | 3.50-5.20 | 26.00-29.00 | 1.00-2.50 | 0.15-0.35 | … | … |
| 32906 | ≤0.03 | 0.80-1.50 | ≤0.030 | ≤0.03 | ≤0.50 | 5.80-7.50 | 28.00-30.00 | 1.50-2.60 | 0.30-0.40 | ≤0.80 | … |
NOTE: PREN:Cr+3.3*(Mo+0.5*W)+16*N≥41 |
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥750 MPa | ≥550 MPa | ≥25% | ≤270 HBW |
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
|---|---|---|---|---|---|
| 7.8 g/cm³ | 1450 °C approx. | 13.5 µm/m·°C (20-100°C) | 15.0 W/m·K (20°C) | 200 GPa | 0.85 x 10⁻⁶ Ω·m (20°C) |
| Specified Outside Diameter (OD) (Inches) | Permissible Variations in OD (± Inches) |
| 1⁄2 to 1 | ±0.005 |
| Over 1 to 1-1⁄2 | ±0.008 |
| Over 1-1⁄2 to 2 | ±0.010 |
| Over 2 to 2-1⁄2 | ±0.012 |
| Over 2-1⁄2 to 3-1⁄2 | ±0.014 |
| Over 3-1⁄2 to 5 | ±0.020 |
| Specified Outside Diameter (OD) (Inches) | Specified Wall Thickness (WT) (Inches) | Permissible Variation (± Inches) |
| 1⁄2 to 1 (Inclusive) | 0.025 to 0.065(Inclusive) | ±0.010 |
| Over 0.065to 0.134 (Inclusive) | ±0.012 | |
| Over 1 to 1-1⁄2 (Inclusive) | 0.025 to 0.065 (Inclusive) | ±0.010 |
| Over 0.065 to 0.134 (Inclusive) | ±0.012 | |
| Over 1-1⁄2 to 2 (Inclusive) | 0.025 to 0.049 (Inclusive) | ±0.011 |
| Over 0.049 to 0.083 (Inclusive) | ±0.012 | |
| Over 0.083 to 0.148 (Inclusive) | ±0.014 | |
| Over 2 to 2-1⁄2 (Inclusive) | 0.032 to 0.065 (Inclusive) | ±0.013 |
| Over 0.065 to 0.109 (Inclusive) | ±0.015 | |
| Over 0.109 to 0.165 (Inclusive) | ±0.017 | |
| Over 2-1⁄2 to 3-1⁄2 (Inclusive) | 0.032 to 0.165 (Inclusive) | ±0.020 |
| Over 0.165 to 0.220 (Inclusive) | ±0.025 | |
| Over 3-1⁄2 to 5 (Inclusive) | 0.083 to 0.165 (Inclusive) | ±0.025 |
| Over 0.165 to 0.220 (Inclusive) | ±0.030 |
- Positive Material Identification (PMI)
- Full traceability of raw materials
Mechanical and Corrosion Testing
- Tensile and hardness testing
- Charpy V-Notch impact testing
- Intergranular corrosion testing (IGC)
Metallurgical Analysis
- Ferrite phase balance verification
- ASTM G48 pitting corrosion testing
Property | Duplex 2205 (S31803 / S32205) | Super Duplex S32760 (F55) |
Microstructure | Dual-phase Austenite/Ferrite | Enhanced Dual-phase with W and Cu |
PREN | 34 – 36 | ≥ 41 |
Yield Strength | Approx. 450 MPa | Approx. 550 MPa |
Chloride Resistance | Excellent in seawater | Superior in hot brine and sour gas |
Critical Pitting Temperature | ~35°C | >50°C |
Dimensional Standards and Tolerances
S32760 super duplex seamless tubes are supplied to the dimensional tolerances of ASTM A789 / A1016 unless a tighter project specification applies.
- For Specific Cut Lengths, the standard tolerance is +1⁄8 in. [3 mm], -0 in. [0 mm].
Important Note: The values presented here are based on the common tables in the ASTM A789 standard. The full specification, particularly the referenced ASTM A1016/A1016M (General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes), contains other essential requirements like straightness and details for tubes with ODs outside of this range. Always consult the latest official standard for design and procurement.
Common Industrial Applications
Oil and Gas Production
- Subsea manifolds and jumpers
- Sour service flowlines
- High-pressure wellhead equipment
Desalination and Water Treatment
- Reverse osmosis high-pressure piping
- Brine heater tubing
- Seawater intake lines
Chemical and Petrochemical Processing
- Reactors and heat exchangers
- Chloride-bearing process piping
- Acid handling equipment
Marine and Offshore Engineering
- Seawater cooling systems
- Firewater and ballast lines
- Offshore platform pipework
Quality Assurance and Manufacturing Process
Certification
All Super Duplex S32760 tubes are supplied to ASTM A789 / ASME SA789 and ASTM A790 / ASME SA790 with EN 10204 3.1 mill test certificates. Third-party inspection (SGS, BV, TUV, Lloyd's), PMI reports and full heat-number traceability can be provided on request.
Non-Destructive Testing (NDT)
Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing (UT) and dye-penetrant inspection (PT) are available for critical service, with records retained for each production lot.
Material Verification
Positive Material Identification (PMI) and spectrometric analysis confirm that the chemical composition matches the ordered grade and that the ferrite/austenite balance is within the specified range.
Mechanical Testing
Tensile, yield, elongation and hardness tests are carried out per heat. Impact testing can be supplied at the project design temperature for subsea and low-temperature service.
Dimensional Inspection
Outside diameter, wall thickness, ovality and straightness are measured against ASTM A1016 / A1016M or ASTM A789 tolerances. Length, square-cut ends and end-finish conditions are verified before packing.
S32760 (Zeron 100) vs S32750 (2507) – Technical Comparison
S32760 and S32750 are the two most widely specified super duplex grades. Their compositions are close, and the difference comes down to tungsten and copper additions.
Chemical Composition
- S32760 (Zeron 100): ~25% Cr, ~3.5% Mo, ~0.7% Cu, ~0.7% W, ~0.25% N
- S32750 (2507): ~25% Cr, ~4% Mo, ~0.3% N, no deliberate Cu or W
- Both have PREN above 40 and a balanced 50:50 microstructure
Corrosion Resistance
The tungsten and copper additions in S32760 widen the corrosion envelope slightly, particularly in reducing acids and in environments where erosion-corrosion matters. In straightforward seawater and chloride service the two grades perform comparably.
Availability and Specification
S32750 is the more widely stocked grade and appears in more project specifications by name. S32760 is frequently specified in subsea and offshore projects where its particular chemistry is recognised by the operator standard.
Selection Guide
- Choose S32760 where the project specification names Zeron 100 or where the tungsten-copper chemistry is preferred
- Choose S32750 for the broadest availability and the largest body of service experience
- Both allow roughly the same wall-thickness reduction against austenitic grades
Frequently Asked Questions
What is S32760 super duplex tube?
UNS S32760, widely known as Zeron 100, is a super duplex stainless steel tube with a balanced 50:50 austenite-ferrite microstructure. Its chromium, molybdenum, nitrogen, tungsten and copper contents give a PREN above 40.
What is the difference between S32760 and S32750?
The compositions are close, both with PREN above 40. S32760 adds tungsten and a small copper addition, which slightly widens the corrosion envelope in reducing acids and erosion-corrosion service. S32750 is more widely stocked and appears in more project specifications by name.
What standard covers S32760 tube?
S32760 seamless tube is supplied to ASTM A789 / ASME SA789 for tubing and ASTM A790 / ASME SA790 for pipe, with dimensional tolerances per ASTM A1016 / A1016M.
What is S32760 tube used for?
S32760 is used for subsea manifolds and jumpers, sour service flowlines, reverse-osmosis high-pressure piping, and offshore seawater systems where both high strength and corrosion resistance are critical.
Ready to Request a Quotation?
Send your Seamless Super Duplex S32760 Tube enquiry with grade, application, size (OD and wall thickness or schedule), quantity, length, end finish and inspection requirements including any ferrite content limits or third-party witnessing.
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