S32707 is a hyper duplex grade with approximately 50% ferrite and 50% austenite. Its high chromium, molybdenum, and nitrogen content delivers a PREN above 49 and yield strength near 700 MP (significantly higher than standard and super duplex grades).
ASTM A790 S32707 Hyper Duplex Seamless Tube
S32707 Hyper Duplex Seamless Tube is a ferritic-austenitic stainless steel product manufactured and supplied by Zhejiang Xintongda Special Steel (XTD). These tubes are also known as UNS S32707, SAF 2707 HD, or simply hyper duplex stainless steel. The alloy contains approximately 26–29% Cr, 5.5–9.5% Ni, 4–5% Mo, and 0.30–0.50% N. Production follows ASTM A790 / A928 standards, using cold rolling, cold drawing, annealing, pickling, and straightening. This combination of chromium, molybdenum, and nitrogen gives the tube a PREN above 49 (among the highest among all duplex grades), along with strong resistance to chloride stress corrosion cracking and pitting. The operating temperature ranges from -50°C to 300°C. We run an annual production capacity of 25,000 tons. Stock items typically ship within one week. Custom production orders are fulfilled in 15 to 60 days, depending on specifications.
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Standard
ASTM A790
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OD Range
6-457 mm
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Thickness
1-65 mm
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Length
≤ 18 m
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How S32707 Hyper Duplex Seamless Tube is Produced
We ensure high-quality S32707 hyper duplex seamless tube by adhering to strict manufacturing procedures. The process starts with a hyper duplex stainless steel ferritic-austenitic ingot. This is then formed into a seamless tube through hot extrusion or piercing. Cold drawing, cold rolling, or pilgering brings the tube to its final, precise dimensions. Solution annealing is used to restore the correct microstructure, and pickling cleans the surface. After straightening, every tube goes through eddy-current testing and a hydrotest. Final steps include cut-to-length and packaging. To know more about the manufacturing process, visit our page.
Key Features of S32707 Hyper Duplex Seamless Tube
6 important characteristics of UNS S32707 seamless tubes are explained below.
- Highest PREN Among Duplex Grades: With PREN above 49, S32707 surpasses Super duplex grades S32750 and S32760 (both at PREN 42) for pitting resistance in chloride environments. This makes it the preferred choice when those grades start to fail.
- Exceptional Strength-to-Weight Ratio: Yield strength of approximately 700 MPa allows for thinner wall designs without compromising structural integrity. This leads to measurable weight reduction in subsea and desalination piping systems.
- Outstanding Chloride Stress Corrosion Resistance: The duplex microstructure and high nitrogen content prevent stress corrosion cracking caused by chlorides at temperatures where regular austenitic grades usually fail.
- Excellent Fatigue Resistance: S32707 has higher fatigue strength than Super Duplex grades. This is useful in cyclic-loaded applications like subsea risers and offshore pipelines where material fatigue is a real concern.
- Good Weldability with Controlled Heat Input: The grade is weldable using matching or overmatching duplex filler metals. Heat input must be carefully controlled to maintain the right balance between ferrite and austenite phases post-weld.
- High Critical Pitting Temperature: According to ASTM G48 Method A, the critical pitting temperature (CPT) is usually higher than 90°C. This means that S32707 can handle much more than what standard and super duplex grades can handle in places where pitting is common.
ASTM A790 S32707 Hyper Duplex Seamless Tube Equivalent Materials
S32707 Hyper Duplex is specified across industries globally. Having clear international equivalents makes procurement more straightforward for engineering projects that span multiple regions.
| GRADE | S32707 Hyper Duplex |
| UNS | S32707 |
| DIN/EN | 1.4658 |
100% Certified Testing & Documentation
Every shipment of S32707 Hyper Duplex seamless tube leaves our facility with complete documentation confirming chemical composition, mechanical performance, corrosion behaviour, and dimensional accuracy. Ferrite content and impact test results at -46°C are included where applicable. Below is a list of the certificates and test reports we provide:
- EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
- Raw Materials Certificate
- 100% PMI (Positive Material Identification)
- Heat Treatment Charts
- Third-Party Inspection Report (TPI / TUV / BV / SGS)
- Surface roughness and dimensional measurement
- Manufacturer Test Certificate (Impact, Flattening, Flare, Bend, Hardness, Intergranular, Pitting Corrosion, Grain Size, ET, UT, HT)
- Laboratory Test Certificate from Government-Approved Lab
S32707 Hyper Duplex Seamless Tube Industrial Applications
S32707 tubes are used in some of the most demanding environments across oil and gas, chemical processing, desalination, and power industries, where standard duplex grades are not adequate.
Subsea Oil and Gas Flowlines
We provide S32707 tubes for subsea manifolds, jumpers, and flowlines that work in deep-water chloride environments at pressures higher than 15,000 psi. Because of its high PREN and mechanical strength, it is the best choice for these conditions.
Deep-Water Offshore Risers
Our S32707 tubes serve offshore production risers and tiebacks. Fatigue and chloride stress corrosion cracking resistance are the primary design requirements here, and SAF 2707 HD tube handles both reliably in umbilical service.
Desalination Plant High-Pressure Piping
We provide S32707 for reverse-osmosis high-pressure headers, energy-recovery devices, and brine-concentrate piping. These lines handle seawater at elevated temperatures, where pitting resistance is a hard requirement.
Chlor-Alkali Plant Piping
Our tubes are used in wet chlorine, hypochlorite, and concentrated brine service inside chlor-alkali facilities. Standard duplex grades are generally not adequate for these conditions.
Mining and Hydrometallurgical Autoclaves
S32707 is used in pressure oxidation autoclaves and acid-chloride leach circuits in copper, nickel, and gold recovery operations where aggressive chemical environments are the norm.
Industrial FGD Absorbers
Our tubes serve limestone and seawater FGD absorbers, where chloride pitting is the primary mechanism limiting service life. The high CPT of S32707 is a direct advantage in these systems.
Frequently Asked Questions
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What is S32707 hyper duplex Stainless Steel?
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How does S32707 compare to Super Duplex grades?S32707 has a yield strength that is almost 15% higher and a pitting resistance that is much higher than S32750 and S32760. It can handle environments with more aggressive chlorides and allows thinner walls in subsea and chemical piping.
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What is the upper service temperature of S32707?The upper temperature of S32707 is approximately 300°C to avoid sigma and chi-phase precipitation. Above this, the ferrite phase becomes unstable, and both corrosion resistance and toughness degrade.
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What testing is required for S32707 Pipes?Compliance with ASTM A790 is the base requirement. Industry practice includes ferrite count per ASTM E562, ASTM G48 Method A pitting test above 50°C, and ASTM A923 detrimental-phase screening using Methods A, B, and C.