SUPER DUPLEX 2507 (UNS S32750) FASTENERS — TECHNICAL DATASHEET & ANALYSIS
Super Duplex 2507 is a high-performance austenitic-ferritic stainless steel designed for service in highly corrosive environments that demand exceptional mechanical strength. Composed of 25% chromium, 4% molybdenum, and 7% nickel, it features a balanced dual-phase microstructure that combines the best properties of both austenitic and ferritic steels.
This metallurgical synergy results in a material with yield strengths nearly double those of conventional 300-series stainless steels, while providing superior resistance to chloride-induced pitting, crevice corrosion, and stress corrosion cracking (SCC).
■ Product Overview
Grade 2507 is characterized by its high energy absorption and low coefficient of thermal expansion, offering significant design advantages for weight-sensitive infrastructure.
| Material Category | Super Duplex Stainless Steel (Austenitic-Ferritic) |
|---|---|
| UNS Designation | S32750 |
| Common Trade Names | SAF 2507, Alloy 2507, 25Cr Duplex |
| Density | 7.8 g/cm³ (0.281 lb/in³) |
| Melting Range | 1350°C – 1460°C (2460°F – 2660°F) |
| Modulus of Elasticity | 200 GPa (29 × 10⁶ psi) |
| Thermal Conductivity | 15 W/m·K at 20°C (8.6 BTU·ft/ft²·hr·°F) |
| Magnetic State | Slightly magnetic (due to ferritic phase) |
■ Proprietary Datasheet Download
Access high-fidelity engineering data for Super Duplex 2507, including CPT/CCT Charts, elevated temperature mechanicals, torque charts, and iso-corrosion curves.
Super Duplex 2507 / UNS S32750 — Complete Technical Datasheet
Detailed dry and lubricated torque-tension values, performance modeling in H2SO4 and HCl acids, and critical pitting data in 1M NaCl and 10% FeCl3.
⬇ DOWNLOAD DATASHEET■ Chemical Composition
The alloy's exceptional performance is driven by its high nitrogen content, which enhances structure stability in the heat-affected zone (HAZ) and increases pitting resistance.
| Element | Content (%) |
|---|---|
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 5.0 |
| Nitrogen (N) | 0.24 – 0.32 |
| Manganese (Mn) | 1.20 max |
| Silicon (Si) | 0.80 max |
| Copper (Cu) | 0.50 max |
| Carbon (C) | 0.030 max |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.020 max |
| Iron (Fe) | Balance |
■ Mechanical Properties
Mechanical properties of 2507 are typically 50-100% higher than standard austenitic stainless steels, allowing for leaner designs in load-bearing applications.
| Mechanical Property | Minimum Value |
|---|---|
| Ultimate Tensile Strength (UTS) | 795 – 1000 MPa (116 ksi) |
| 0.2% Yield Strength | 550 – 850 MPa (80 ksi) |
| Elongation (% in 50mm) | 15% – 25% |
| Hardness (Rockwell C) | 32 HRC max |
| Hardness (Brinell HBW) | 290 – 310 HBW max |
| Impact Toughness (-50°C) | > 100 J |
■ Equivalent Grades
Super Duplex 2507 is cross-referenced across global standards to ensure international interchangeability for large-scale EPC projects.
| Standard / System | Equivalent Grade |
|---|---|
| UNS (USA) | S32750 |
| EN Number (Europe) | 1.4410 |
| EN Name | X2CrNiMoN 25-7-4 |
| AFNOR (France) | Z3 CN 25.06 Az |
| SS (Sweden) | 2328 |
| ASTM | Grade F53 |
| DIN (Germany) | W.Nr. 1.4410 |
■ Applications & Industries
Grade 2507 is utilized where standard duplex grades (like 2205) or austenitic grades (like 316L) reach their corrosion or strength limits.
- Offshore Oil & Gas: Subsea umbilicals, risers, firewater systems, and ballast water systems.
- Chemical Processing: Heat exchangers, pressure vessels, and piping for organic and inorganic acids.
- Desalination Plants: High-pressure RO plants, brine piping, and seawater intake systems.
- Marine Engineering: Propellers, shafts, and structural fixings exposed to high-chloride environments.
- Power Industry: Flue gas desulfurization (FGD) systems, scrubbers, and ducting.
■ Fastener Types Available
Ananka Group provides a comprehensive inventory of Super Duplex 2507 fasteners, ranging from micro-sizes to heavy-duty industrial components.
- Bolts: Hex bolts, heavy hex bolts, carriage bolts, U-bolts, eye bolts, and socket head bolts.
- Nuts: Hex nuts, jam nuts, lock nuts, nylock nuts, wing nuts, and coupling nuts.
- Screws: Machine screws, self-tapping screws, set screws, and socket cap screws.
- Washers: Flat washers, spring washers, lock washers, and square washers.
- Studs: Fully threaded rods, double-end studs, tap-end studs, and weld studs.
■ Standards & Specifications
Fasteners are manufactured to meet the most stringent international engineering codes for pressure and safety integrity.
- ASTM/ASME: ASTM A479, A276, A182 (Grade F53), A193, A194.
- Dimensional Standards: DIN 931, 933, 934, 975, 125 / ASME B18.2.1, B18.2.2.
- Threads: UNC, UNF, Metric Coarse, Metric Fine, and BSW.
- Size Range: Metric M3 to M100 | Imperial 1/4" to 4".
- Coatings: PTFE (Xylan), Zinc-Nickel, Hot Dip Galvanized, and Cadmium plating.
■ Material Test Certificate (MTC)
Reliability in critical infrastructure depends on full material traceability. Ananka Group ensures that every fastener batch is accompanied by authenticated Material Test Certificates (MTC).
- EN 10204 Type 3.1: This standard certificate, issued by the manufacturer, confirms specific test results (chemical/mechanical) for the unique heat (batch) of steel.
- EN 10204 Type 3.2: For high-risk applications like subsea hardware or nuclear power, an independent third-party inspector witnesses the testing and provides a co-signed certificate for maximum assurance.
■ Why Choose Ananka Group?
Ananka Group is a manufacturing-driven organization in Mumbai specializing in exotic alloy metallurgy for critical industrial sectors.
- PED 2014/68/EU Certified: Approved for manufacturing fasteners for high-pressure equipment by TÜV Rheinland.
- Integrated Quality Systems: Operations audited under ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018.
- In-House Manufacturing: Capabilities including hot forging (for large diameters up to M100), cold thread rolling, and precision CNC machining.
- Exotic Metallurgy: Beyond 2507, Ananka specializes in Hastelloy, Inconel, Monel, and Titanium grades.
- Global Logistics: Proven export record to the USA, UK, Europe, and Middle East from Mumbai and Kalamboli ports.
■ Frequently Asked Questions
1. Is Super Duplex 2507 magnetic?
Yes, 2507 is slightly magnetic. While austenitic steels (like 316) are typically non-magnetic, 2507 contains a significant ferritic phase (typically 35–55%), which exhibits magnetic behavior.
2. What is the maximum service temperature for 2507?
The recommended upper limit is 600°F (315°C). Prolonged exposure to temperatures above 300°C (572°F) can lead to the formation of secondary phases that cause embrittlement and a loss of corrosion resistance.
3. What is the significance of the PREN value for this grade?
The Pitting Resistance Equivalent Number (PREN) for 2507 is typically > 42. Calculated as $PREN = \%Cr + 3.3 \times \%Mo + 16 \times \%N$, this value confirms 2507's superior performance against localized pitting compared to Duplex 2205 (PREN 35) and 316L (PREN 24).
4. How does 2507 compare to Duplex 2205?
2507 offers significantly higher strength and corrosion resistance due to its increased chromium, molybdenum, and nitrogen content. While 2205 is more cost-effective for general industrial use, 2507 is preferred for aggressive seawater and high-pressure subsea environments.
5. Are special filler metals required for welding 2507?
Yes, to maintain the dual-phase structure and corrosion resistance in the weld, over-alloyed filler metals like E2594 or ER2594 are mandatory.
6. Can 2507 fasteners be used for cryogenic applications?
Yes, Super Duplex 2507 maintains good impact toughness at room and cryogenic temperatures (down to -50°C), making it versatile for diverse climate conditions.
For project-specific technical support or to receive a custom quote for Super Duplex 2507 fasteners, please contact the Ananka Group Sales Team at sales@anankafasteners.com or via WhatsApp at +91 86557 47687. Ensure the integrity of your high-pressure systems with PED-certified components.