Overview
Super Duplex 2507 Stainless Steel (UNS S32750) is a high-alloy super duplex stainless steel designed for the most demanding corrosive environments. It features a balanced microstructure of approximately 50% Austenite and 50% Ferrite, combining extremely high mechanical strength with exceptional corrosion resistance.
Super Duplex 2507 offers superior resistance to:
- Chloride Pitting Corrosion
- Crevice Corrosion
- Stress Corrosion Cracking (SCC)
- Seawater Corrosion
- Acidic Chemical Attack
Due to its outstanding performance, Super Duplex 2507 is extensively used in offshore oil & gas, subsea systems, desalination plants, marine engineering, chemical processing, pressure vessels, heat exchangers, and high-performance industrial equipment.
Compared with Duplex 2205, Super Duplex 2507 provides significantly higher corrosion resistance and strength, making it one of the highest-performing stainless steels commercially available.
Material Specification
| Property | Value |
|---|---|
| Material Designation | Super Duplex 2507 |
| Material Family | Super Duplex Stainless Steel |
| UNS Number | S32750 |
| EN Grade | 1.4410 |
| Density | 7.80 g/cm³ |
| Magnetic Property | Slightly Magnetic |
| Standard Forms | Plate, Sheet, Coil, Pipe, Tube, Bar, Forgings |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| 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) | ≤0.03 |
| Manganese (Mn) | ≤1.20 |
| Silicon (Si) | ≤0.80 |
| Phosphorus (P) | ≤0.035 |
| Sulfur (S) | ≤0.020 |
| Copper (Cu) | ≤0.50 |
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥800 MPa |
| Yield Strength | ≥550 MPa |
| Elongation | ≥15% |
| Hardness | ≤310 HB |
| Elastic Modulus | 200 GPa |
Strength Comparison
| Material | Yield Strength |
|---|---|
| Super Duplex 2507 | ≥550 MPa |
| Duplex 2205 | ≥450 MPa |
| SS316L | ≥170 MPa |
| SS304L | ≥170 MPa |
Super Duplex 2507 provides approximately 3 times the yield strength of SS316L.
Physical Properties
| Property | Value |
|---|---|
| Density | 7.80 g/cm³ |
| Melting Point | 1350–1450°C |
| Thermal Conductivity | 14.0 W/m·K |
| Electrical Resistivity | 0.80 μΩ·m |
| Thermal Expansion Coefficient | 13.5 × 10⁻⁶/K |
| Specific Heat Capacity | 460 J/kg·K |
Corrosion Resistance
Corrosion Performance
| Environment | Performance |
|---|---|
| Seawater | Exceptional |
| Offshore Environment | Exceptional |
| Chloride Exposure | Exceptional |
| Salt Spray | Exceptional |
| Acidic Solutions | Excellent |
| Sulfuric Acid | Excellent |
| Chemical Processing | Exceptional |
PREN Value (Pitting Resistance Equivalent Number)
| Material | PREN |
|---|---|
| SS304 | 18–20 |
| SS316L | 24–26 |
| Duplex 2205 | 34–36 |
| Super Duplex 2507 | 40–45+ |
A PREN value above 40 classifies Super Duplex 2507 as a true Super Duplex Stainless Steel.
Stress Corrosion Cracking Resistance
Super Duplex 2507 provides outstanding resistance to:
- Chloride Stress Corrosion Cracking (SCC)
- Pitting Corrosion
- Crevice Corrosion
- Erosion Corrosion
- Corrosion Fatigue
- Intergranular Corrosion
This makes it one of the best materials available for seawater and offshore applications.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | Super Duplex 2507 |
| UNS | S32750 |
| EN (Europe) | 1.4410 |
| DIN (Germany) | X2CrNiMoN25-7-4 |
| JIS (Japan) | SUS329J4L |
| GB/T (China) | 022Cr25Ni7Mo4N |
| ISO | X2CrNiMoN25-7-4 |
Available Forms
| Product Type | Availability |
|---|---|
| Stainless Plate | Yes |
| Stainless Sheet | Yes |
| Coil | Yes |
| Pipe | Yes |
| Tube | Yes |
| Round Bar | Yes |
| Forgings | Yes |
| Flanges | Yes |
| Pressure Vessel Components | Yes |
Typical Applications
Offshore Oil & Gas Industry
- Offshore Platforms
- Subsea Equipment
- Manifolds
- Flowlines
- Risers
- Pressure Control Systems
Marine Engineering
- Seawater Piping
- Shipbuilding Components
- Marine Fasteners
- Propulsion Systems
- Offshore Structures
Desalination Industry
- Reverse Osmosis Systems
- High Pressure Pumps
- Seawater Intake Equipment
- Brine Handling Systems
Chemical Processing Industry
- Heat Exchangers
- Reactors
- Storage Tanks
- Process Piping
- Chemical Transfer Systems
Power Generation
- Cooling Water Systems
- Flue Gas Desulfurization Equipment
- Condensers
- Heat Recovery Units
Pulp & Paper Industry
- Bleaching Systems
- Digesters
- Chemical Recovery Equipment
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Good |
| CNC Milling | Good |
| Laser Cutting | Excellent |
| Waterjet Cutting | Excellent |
| Bending | Good |
| Forming | Good |
| TIG Welding | Excellent |
| MIG Welding | Excellent |
| Plasma Cutting | Excellent |
| Polishing | Good |
Advantages
Exceptional Corrosion Resistance
Among the highest corrosion-resistant stainless steels available.
Outstanding Mechanical Strength
Higher strength than Duplex 2205 and austenitic stainless steels.
Superior SCC Resistance
Ideal for chloride-rich environments.
Weight Reduction Potential
Allows thinner wall designs due to high strength.
Long Service Life
Reduces maintenance and lifecycle costs.
Alternative to Nickel Alloys
Provides excellent performance at significantly lower cost than many nickel-based alloys.
Limitations
Higher Material Cost
More expensive than Duplex 2205 and SS316L.
More Difficult Machining
Requires rigid setups and optimized tooling.
Strict Welding Procedures Required
Heat input and cooling rates must be controlled.
Not Recommended Above 300°C Continuous Service
Duplex phase balance may deteriorate at elevated temperatures.
Comparison with Other Stainless Steels
| Property | Super Duplex 2507 | Duplex 2205 | SS316L | SS904L | SS304L |
|---|---|---|---|---|---|
| Yield Strength | Outstanding | Excellent | Medium | Medium | Medium |
| Corrosion Resistance | Exceptional | Outstanding | Excellent | Outstanding | Good |
| SCC Resistance | Exceptional | Outstanding | Moderate | Excellent | Poor |
| Pitting Resistance | Exceptional | Excellent | Good | Excellent | Moderate |
| Marine Applications | Outstanding | Excellent | Good | Excellent | Limited |
| Cost | Very High | High | Medium | High | Medium |
Comparison with High-Performance Alloys
| Material | Yield Strength (MPa) | PREN | Marine Use |
|---|---|---|---|
| Super Duplex 2507 | ≥550 | 40–45+ | Outstanding |
| Duplex 2205 | ≥450 | 34–36 | Excellent |
| SS904L | ≥220 | 35 | Excellent |
| Titanium Grade 2 | ≥275 | N/A | Outstanding |
| Inconel 625 | ≥460 | N/A | Outstanding |
| Hastelloy C276 | ≥355 | N/A | Outstanding |
Available Surface Finishes
Mill Finishes
- No.1 Finish
- Hot Rolled Finish
- Pickled Finish
- Annealed Finish
Decorative Finishes
- Satin Finish
- Brushed Finish
- Mirror Polish
- Glass Bead Finish
Functional Finishes
- Passivation
- Electropolishing
- Pickling
- Shot Blasting
- Anti-Corrosion Surface Treatment
Frequently Asked Questions (FAQ)
What is Super Duplex 2507 stainless steel?
Super Duplex 2507 is a high-alloy duplex stainless steel designed for extreme corrosion resistance and high-strength applications.
What is Super Duplex 2507 used for?
Typical applications include:
- Offshore Platforms
- Subsea Equipment
- Seawater Systems
- Desalination Plants
- Chemical Processing Equipment
- Pressure Vessels
Is Super Duplex 2507 stronger than Duplex 2205?
Yes.
| Property | Super Duplex 2507 | Duplex 2205 |
|---|---|---|
| Yield Strength | ≥550 MPa | ≥450 MPa |
| Tensile Strength | ≥800 MPa | ≥620 MPa |
What is the difference between Duplex 2205 and Super Duplex 2507?
| Property | Duplex 2205 | Super Duplex 2507 |
|---|---|---|
| Chromium | 22–23% | 24–26% |
| PREN | 34–36 | 40–45+ |
| Corrosion Resistance | Excellent | Exceptional |
| Strength | High | Higher |
Is Super Duplex 2507 marine grade?
Yes. It is considered one of the best stainless steels for marine and offshore environments.
Is Super Duplex 2507 magnetic?
Yes. Like all duplex stainless steels, it is slightly magnetic.
Can Super Duplex 2507 be welded?
Yes. Proper welding procedures are required to maintain phase balance and corrosion resistance.
Why is Super Duplex 2507 widely used offshore?
Because it combines:
- Exceptional Corrosion Resistance
- Outstanding Strength
- Superior SCC Resistance
- Long Service Life
making it ideal for aggressive seawater applications.
Is Super Duplex 2507 better than SS316L?
For offshore, marine, and chloride environments, Super Duplex 2507 significantly outperforms SS316L.
Does GCNOV provide custom manufacturing services for Super Duplex 2507?
Yes. GCNOV provides:
- CNC Machining
- CNC Turning & Milling
- Precision Welding
- Pipe Fabrication
- Pressure Vessel Components
- Offshore Equipment Manufacturing
- Surface Finishing
- Prototype Development
- Low-Volume Production
- Mass Production