ASTM A790 S32750, also known as Super Duplex 2507 or UNS S32750 (Werkstoff Nr. 1.4410, F53), is a super duplex (austenitic-ferritic) stainless steel with a balanced dual-phase microstructure (approximately 50% austenite and 50% ferrite). This unique microstructure combines the best properties of both austenitic and ferritic stainless steels, delivering an exceptional balance of mechanical strength and corrosion resistance.
Compared to standard duplex grades such as S31803 (2205), Super Duplex 2507 features higher chromium (24.0–26.0%), molybdenum (3.0–5.0%), and nitrogen content, enabling outstanding performance in aggressive, chloride-rich environments such as seawater, brine, and chemical processing fluids. The material also offers a high Pitting Resistance Equivalent Number (PREn) typically exceeding 40, guaranteeing superior resistance to pitting and crevice corrosion.
Key Features:
| Feature | Advantage |
| Dual-phase (austenite + ferrite) microstructure | Superior strength with excellent corrosion resistance |
| High Cr, Mo & N content | Excellent resistance to pitting, crevice corrosion and SCC |
| >40 PREn | Guarantees high resistance to localized corrosion |
| 25% Cr, 7% Ni, 4% Mo nominal composition | Suitable for highly corrosive chloride-rich environments |
| High mechanical strength (≥800 MPa tensile) | Allows use of thinner wall thicknesses without compromising performance |
| Good weldability | Compatible with standard welding processes |
Technical Specifications
1.Standard and Equivalent Specifications
| Standard | Designation |
| ASTM | A790 (Pipe), A789 (Tube) |
| ASME | SA790 |
| UNS | S32750 |
| EN | 1.4410 (X2CrNiMoN 25-7-4) |
| DIN | 17458, 17456 |
| GOST | 9941-81, 9940-81 |
| Trade Names | Super Duplex 2507 |
2. Chemical Composition (wt%)
| Element | Cr | Ni | Mo | N | C | Mn | Si | P | S | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| S32750 | 24.0-26.0 | 6.0-8.0 | 3.0-5.0 | 0.24-0.32 | ≤0.03 | ≤1.20 | ≤0.80 | ≤0.035 | ≤0.02 | Balance |
3.Mechanical Properties
| Property | Value (min) |
| Tensile Strength | ≥116 ksi (≥800 MPa) |
| 0.2% Yield Strength | ≥80 ksi (≥550 MPa) |
| Elongation (2" or 50mm) | ≥15% |
| Hardness (Brinell HBW) | ≤300 |
| Hardness (Rockwell HRC) | ≤32 |
4. Dimensional Specifications
Outer Diameter (OD): 1/8" - 36" (DN10 - DN914mm)
Wall Thickness: SCH 5S - SCH XXS (0.3mm - 50mm)
Length: Random length (5-7m) or customized fixed length
Tolerance: Strictly per ASME B36.10M / ASTM A790
Dimensional Ranges (Seamless Pipe & Tube)
| Parameter | Range |
| Outer Diameter (OD) | 1/8" to 24" NPS (seamless); 3.18 mm to 31.75 mm for precision tubing |
| Wall Thickness | SCH 5 to SCH 160 (all schedules available) |
| Lengths | Single Random Length (SRL), Double Random Length (DRL), or Cut-to-length |
| End Preparation | Plain ends, beveled ends, threaded ends |
| Surface Finish | 2B, No.1, No.4, No.8 Mirror Finish, Pickled & Annealed, Bright Annealed, Polished |
5. Heat Treatment
| Parameter | Requirement |
| Annealing Temperature | 1025–1125°C (1880–2060°F) |
| Quenching Method | Rapid cooling in air or water (solution annealed) |
| Surface Condition | Pickled free of scale (bright annealing may eliminate need for pickling) |
Applications
1. Oil & Gas (Offshore/Onshore)
- Subsea flowlines, offshore platform piping (seawater cooling, fire suppression)
- Acidic gas/oil production (H₂S-containing media), hydraulic umbilicals
2. Marine & Desalination
- Seawater reverse osmosis (RO) pressure vessels, high-pressure intake/outlet lines
- Shipbuilding piping, coastal infrastructure, seawater heat exchangers
3. Chemical & Petrochemical
- Chloride-rich process piping, heat exchanger tubes, reactor internals
- Sulfuric/hydrochloric acid service, hydrocarbon processing units
4. Power & Environmental
- Flue Gas Desulfurization (FGD) systems, waste heat recovery exchangers
- Geothermal well piping (high-salinity brines), nuclear power plant auxiliary systems
5. Pulp & Paper
- Bleach plant piping, black liquor recovery systems, corrosive chemical handling
China's Main Export Markets
China is a leading global manufacturer of 2507 super duplex seamless pipes, with mature production technology and large-scale capacity. Key export markets include:
- Middle East: UAE, Saudi Arabia, Kuwait (desalination, offshore oil/gas projects)
- Europe: UK, Germany, Norway (offshore platforms, chemical processing)
- North America: USA, Canada (oil sands, coastal infrastructure)
- Asia-Pacific: Singapore, Australia, South Korea (marine engineering, petrochemicals)
- Latin America: Brazil, Mexico (offshore oil, desalination)
China's Price Advantage
China's 2507 seamless pipes offer unmatched cost competitiveness without compromising quality:
2025 Price Range: USD 2,800-6,000 per metric ton (FOB China)
vs. Europe: 30-40% lower than European mills (USD 4,000-9,000/ton)
vs. USA: 40-50% lower than US suppliers (USD 4,500-12,000/ton)
Key Cost Drivers:
Lower raw material premiums (domestic Cr/Mo/Ni supply chain)
Advanced manufacturing (cold drawing + solution annealing, high automation)
Large-scale production (economies of scale, reduced unit costs)
Flexible MOQ & fast delivery (7-10 days for standard sizes)
FAQ
FQ1: What is the difference between 2507 (S32750) and 2205 (S31803)?
2507 (Super Duplex): Higher Cr (25%), Mo (4%), N (0.27%); PREN >40; higher strength (550MPa yield); better for extreme chloride/high-temperature environments.
2205 (Standard Duplex): Lower Cr (22%), Mo (3%), N (0.15%); PREN 30-35; lower strength (450MPa yield); suitable for moderate corrosion environments.
Q2: Can 2507 pipes be welded on-site?
Yes. Use E2594 filler metal; avoid prolonged high-temperature exposure (prevents harmful sigma phase precipitation). No post-weld heat treatment required.
Q3: What is the maximum operating temperature for 2507?
Continuous: -50°C to 300°C; Intermittent: Up to 350°C. Avoid 300-500°C long-term (sigma phase risk).
Q4: Are China-made 2507 pipes certified for international projects?
Yes. All products comply with ASTM A790, ASME SA790, API 5L; certified by ISO 9001, PED, CE; full material test reports (MTR) available.
Q5: What is the typical lead time for orders?
Standard Sizes: 7-10 days (stock available)
Custom Sizes: 15-20 days (production + inspection)
Shipping: FOB Shanghai/Ningbo (global delivery via sea/air)
Why Choose Our ASTM A790 S32750 (2507) Pipes?
Premium Quality: Strict quality control (100% UT/RT/PT, PMI testing)
Competitive Pricing: China factory direct sales (no middlemen)
Customization: Tailored sizes, lengths, certifications per project needs
Global Service: 24/7 technical support, fast delivery, reliable after-sales service
Our address
Rm1406,14th/F No 208, Hongqi Road, Nankai Dist, Tianjin City ,China
Phone Number (WhatsApp/Wechat)
+86 16622033809
alisa@tjshenzhoutong.com
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