2507 Super Duplex Stainless Steel
2507 Super Duplex Stainless Steel (UNS S32750 / EN 1.4410)
2507 Super Duplex Stainless Steel (UNS S32750 / EN 1.4410) is a high-performance super duplex stainless steel combining an approximately balanced austenitic-ferritic microstructure with high levels of chromium, molybdenum, and nitrogen.
This alloy provides an excellent combination of very high mechanical strength and outstanding corrosion resistance, particularly in chloride-containing and marine environments. It offers excellent resistance to pitting corrosion, crevice corrosion, and chloride-induced stress corrosion cracking.
Compared with conventional austenitic grades such as 316L and standard Duplex 2205, 2507 Super Duplex generally provides higher strength and superior localized corrosion resistance. It is therefore widely selected for demanding applications where both mechanical performance and corrosion resistance are critical.
2507 Super Duplex Stainless Steel is commonly used in oil & gas, offshore, petrochemical, marine, desalination, chemical processing, water treatment, and power-generation industries.
Emirerri Steel supplies 2507 Super Duplex Stainless Steel in sheets, plates, pipes, tubes, round bars, flanges, and pipe fittings for projects across Tunisia, Algeria, Morocco, Libya, and international markets.
Key Features
- Austenitic-ferritic duplex microstructure
- Very high mechanical strength
- Excellent general corrosion resistance
- Excellent pitting corrosion resistance
- Excellent crevice corrosion resistance
- Excellent chloride-induced stress corrosion cracking resistance
- Excellent resistance to chloride-containing environments
- Excellent seawater resistance
- Good erosion and abrasion resistance
- Good fatigue resistance
- Good weldability with qualified procedures
- High strength-to-weight ratio
- Long service life
Specifications
| Specification | Details |
|---|---|
| Grade | Super Duplex Stainless Steel 2507 |
| UNS | S32750 |
| Werkstoff Number | 1.4410 |
| EN Designation | X2CrNiMoN25-7-4 |
| Type | Super Duplex Stainless Steel |
| Microstructure | Austenite + Ferrite |
| Common Standards | ASTM A240, ASTM A276, ASTM A790, ASTM A789, ASTM A182, EN 10088 |
| Supply Condition | Solution Annealed |
| Surface Finishes | No.1, 2B, BA, No.4, Mirror |
| Product Forms | Sheet, Plate, Pipe, Tube, Round Bar, Flanges, Pipe Fittings |
Equivalent Grades of 2507 Super Duplex
| Standard | Equivalent Grade |
|---|---|
| ASTM / UNS | S32750 |
| EN | 1.4410 |
| EN Designation | X2CrNiMoN25-7-4 |
| DIN | X2CrNiMoN25-7-4 |
| JIS | SUS329J4L* |
| ISO | X2CrNiMoN25-7-4 |
*Equivalent grades should be verified according to product form and the applicable project standard.
Available Sizes
2507 Sheets & Plates
- Thickness: 0.5 to 100 mm
- Width: Up to 2500 mm
- Length: Up to 12000 mm
2507 Pipes & Tubes
- Outside Diameter: 6 to 610 mm
- Wall Thickness: 0.5 to 40 mm
2507 Round Bars
- Diameter: 6 to 500 mm
Actual availability depends on product form, applicable standard, manufacturing method, supply condition, and project requirements.
2507 Super Duplex Chemical Composition
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 5.0 |
| Nitrogen (N) | 0.24 – 0.32 |
| Carbon (C) | ≤ 0.030 |
| Manganese (Mn) | ≤ 1.20 |
| Silicon (Si) | ≤ 0.80 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.020 |
| Copper (Cu) | ≤ 0.50 |
| Iron (Fe) | Balance |
2507 Super Duplex Mechanical Properties
Values can vary according to product form and applicable specification.
| Property | Typical Minimum Value |
|---|---|
| Tensile Strength | ≥ 795 MPa |
| Yield Strength (0.2% Offset) | ≥ 550 MPa |
| Elongation | ≥ 15% |
| Hardness | ≤ 310 HB |
| Modulus of Elasticity | ≈ 200 GPa |
The high yield strength of 2507 allows it to withstand significant mechanical loads and can potentially reduce component thickness in suitably designed applications.
2507 Super Duplex Physical Properties
| Property | Approximate Value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting Range | ≈ 1350 – 1400°C |
| Thermal Conductivity | ≈ 15 W/m·K |
| Specific Heat Capacity | ≈ 500 J/kg·K |
| Modulus of Elasticity | ≈ 200 GPa |
| Magnetic Permeability | Higher than austenitic grades |
Because of its ferritic phase, 2507 Super Duplex Stainless Steel is magnetic.
Types of 2507 Super Duplex Stainless Steel Products
2507 Sheets & Plates
Used in pressure vessels, storage tanks, offshore structures, desalination plants, chemical equipment, and heavy industrial fabrication.
2507 Pipes & Tubes
Suitable for offshore piping, seawater systems, oil & gas facilities, chemical processing, and highly corrosive fluid-handling systems.
2507 Heat Exchanger Tubes
Used in heat exchangers, condensers, and cooling systems exposed to seawater and high-chloride fluids.
2507 Round Bars
Used for shafts, pumps, valves, fasteners, bolts, machined components, and high-strength mechanical parts.
2507 Flanges & Pipe Fittings
Used in high-pressure piping systems and highly corrosive industrial environments.
Corrosion Resistance
Corrosion resistance is one of the most important advantages of 2507 Super Duplex Stainless Steel.
It provides excellent resistance to:
- General corrosion
- Pitting corrosion
- Crevice corrosion
- Chloride-induced stress corrosion cracking
- Seawater corrosion
- High-chloride environments
- Marine atmospheres
- Many aggressive chemical environments
- Erosion-corrosion
2507 typically has a PREN (Pitting Resistance Equivalent Number) above 40, indicating excellent resistance to localized corrosion.
It is commonly selected when conventional austenitic grades or Duplex 2205 cannot provide the required corrosion performance.
Heat Resistance
2507 Super Duplex Stainless Steel offers good oxidation resistance and retains high mechanical strength at moderate temperatures.
However, prolonged exposure to certain elevated temperatures can cause precipitation of undesirable intermetallic phases, particularly sigma phase, which can significantly reduce toughness and corrosion resistance.
Therefore, 2507 is generally not intended for continuous service at very high temperatures.
For high-temperature applications, the actual operating temperature, exposure time, thermal cycles, and applicable design code should be evaluated before material selection.
Heat Treatment
Solution Annealing
2507 Super Duplex Stainless Steel is generally solution annealed at approximately:
1025 – 1125°C
followed by rapid cooling.
Objectives
- Restore the austenite-ferrite balance
- Dissolve undesirable intermetallic phases
- Optimize corrosion resistance
- Improve ductility
- Relieve internal stresses
Careful control of heat treatment is essential because the duplex microstructure is sensitive to thermal exposure.
Welding
2507 has good weldability when suitable and qualified welding procedures are used.
Recommended Welding Processes
- GTAW / TIG
- GMAW / MIG
- SMAW
- SAW
- FCAW
- Orbital Welding
Important Welding Considerations
Careful control of:
- Heat input
- Interpass temperature
- Cooling rate
- Ferrite/austenite balance
is essential to maintain the required mechanical and corrosion properties.
Improper welding can result in:
- Excessive ferrite
- Reduced toughness
- Reduced corrosion resistance
- Formation of undesirable intermetallic phases
Welding procedures should therefore be qualified according to applicable standards and project requirements.
Fabrication
Machining
- Turning
- Milling
- Drilling
- Threading
Due to its high strength and work-hardening characteristics, 2507 can be more difficult to machine than conventional austenitic stainless steels.
Forming
- Bending
- Roll forming
- Cold forming
- Deep drawing
- Press forming
Higher forming forces may be required because of its high yield strength.
Cutting
- Laser cutting
- Plasma cutting
- Waterjet cutting
- Mechanical sawing
Surface Finishing
- Pickling
- Passivation
- Mechanical polishing
- Electropolishing
Applications
Oil & Gas Industry
- Offshore piping
- Production equipment
- Separators
- Pressure equipment
- Process systems
- Subsea components
Petrochemical Industry
- Heat exchangers
- Storage tanks
- Process piping
- Chemical processing equipment
Desalination
- Reverse osmosis equipment
- Seawater piping
- Pumps
- Heat exchangers
- Desalination systems
Marine & Offshore
- Seawater piping
- Offshore structures
- Marine equipment
- Shipbuilding components
Chemical Industry
- Chemical reactors
- Storage tanks
- Process piping
- Pressure vessels
Power Generation
- Cooling systems
- Heat exchangers
- Industrial piping
- Auxiliary equipment
2507 Super Duplex Stainless Steel in Tunisia, Algeria, Morocco & Libya
2507 Super Duplex Stainless Steel is particularly suitable for industrial projects across Tunisia, Algeria, Morocco, and Libya where exceptional corrosion resistance and high mechanical strength are required.
It is well suited to oil & gas, petrochemical, desalination, water treatment, marine, offshore, chemical processing, and power-generation applications.
For North African projects exposed to seawater, high chloride concentrations, aggressive process fluids, or demanding mechanical loads, 2507 can be selected when conventional stainless steel or Duplex 2205 does not provide the required performance.
2507 Super Duplex vs Duplex 2205
| Property | Super Duplex 2507 | Duplex 2205 |
|---|---|---|
| Microstructure | Austenite + Ferrite | Austenite + Ferrite |
| Chromium | 24–26% | 22–23% |
| Molybdenum | 3–5% | 3–3.5% |
| PREN | > 40 | > 30 |
| Yield Strength | ≥ 550 MPa | ≥ 450 MPa |
| Tensile Strength | ≥ 795 MPa | ≥ 620 MPa |
| Chloride Resistance | Excellent | Very Good |
| Seawater Resistance | Excellent | Very Good |
| Pitting Resistance | Excellent | Very Good |
| Alloy Level | Very High | High |
Conclusion
2507 Super Duplex Stainless Steel (UNS S32750 / EN 1.4410) is a high-performance duplex stainless steel combining very high mechanical strength with outstanding corrosion resistance.
Its high levels of chromium, molybdenum, nitrogen, and nickel provide excellent resistance to pitting, crevice corrosion, chloride-induced stress corrosion cracking, and aggressive marine environments.
Available in sheets, plates, pipes, tubes, round bars, flanges, and pipe fittings, 2507 Super Duplex Stainless Steel is a reliable solution for demanding applications in oil & gas, petrochemical, desalination, marine, chemical processing, water treatment, offshore, and power-generation industries across Tunisia, Algeria, Morocco, Libya, and international markets.
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