Super Duplex Stainless Steel 2507 (UNS S32750)
Super Duplex 2507 is a high-alloy, high-performance stainless steel designed for service in highly corrosive conditions that would compromise standard Duplex 2205. With a refined 50/50 balance of austenite and ferrite, it contains 25% Chromium, 7% Nickel, and 4% Molybdenum. This "Super" designation is earned through its exceptional Pitting Resistance Equivalent Number (PREN > 40), making it virtually immune to pitting and crevice corrosion in seawater and other aggressive halide environments.
At Aries Alloys, we supply Super Duplex 2507 for mission-critical offshore and chemical applications. It is the ultimate solution when you need the structural strength of a high-tensile steel combined with the chemical resistance of a high-end nickel alloy.
Key Performance Benefits
- Maximum Corrosion Defense: Exceptional resistance to pitting, crevice corrosion, and uniform corrosion in organic and inorganic acids.
- Extreme Mechanical Strength: Offers significantly higher yield and tensile strength than even Duplex 2205, allowing for extreme weight reduction in high-pressure systems.
- SCC Immunity: Total resistance to chloride-induced stress corrosion cracking in temperatures up to 300°F.
- Erosion & Cavitation Resistance: High hardness and surface integrity make it ideal for high-velocity fluid environments like pumps and nozzles.
- Thermal Efficiency: Lower thermal expansion and higher thermal conductivity than austenitic steels, reducing thermal fatigue in heat-exchange equipment.
Technical Profile & Composition
The Power of Nitrogen & Molybdenum:
The "Super" performance of 2507 is driven by its high Molybdenum (3-5%) and Nitrogen (0.24-0.32%) content. Nitrogen not only increases the pitting resistance but also strengthens the metal's matrix, ensuring that the 50/50 phase balance remains stable even after welding.
Mechanical & Physical Data:
- Density: 7.80 g/cm^3
- Yield Strength: ≥ 550 MPa (80,000 psi)
- Magnetic Property: Magnetic (due to the ferrite phase).
- ASME Approval: Widely used in ASME-coded pressure vessels and piping systems.
Other Notable Duplex Grades
While 2507 is the flagship, Aries Alloys also provides specialized duplex variations for specific industrial needs:
- Lean Duplex 2101 (UNS S32101): A cost-effective alternative to Type 304 and 316. It offers high strength and good corrosion resistance but uses lower nickel and molybdenum, making it ideal for structural water tanks and bridge reinforcements.
- Super Duplex 2507 (UNS S32760 / Zeron® 100): A variation of 2507 that includes additions of Tungsten and Copper. This grade is specifically designed for enhanced resistance to corrosion in hot, sour (containing H2S) environments and concentrated mineral acids.
Primary Industrial Use Cases
- Offshore Energy: Subsea umbilicals, riser pipes, manifolds, and structural components for deep-water platforms.
- Desalination: High-pressure reverse osmosis membranes, seawater intake piping, and pump housings.
- Chemical Processing: Equipment for the production of specialized chemicals, phosphoric acid, and nitric acid.
- Marine Hardware: Propeller shafts, rudders, and high-strength fasteners for naval vessels.
- Pollution Control: Scrubber systems for maritime vessels and industrial flue gas cleaning.