In modern industries where extreme pressure, aggressive environments, and structural strength are daily challenges, Super Duplex Stainless Steel stands out as an essential material. Combining superior corrosion resistance, mechanical strength, and ease of maintenance, super duplex stainless steel is the go-to solution for industrial applications like offshore platforms, chemical plants, desalination, and high-pressure piping systems.
If you’re sourcing super duplex stainless steel sheets, plates, super duplex flanges, or looking for easy-to-maintain super duplex pipe options, this guide dives deep into its properties, applications, grades, and buying insights.
What Is Super Duplex Stainless Steel?
Super Duplex Stainless Steel, a high-alloy material, comprises approximately 50% austenite and 50% ferrite in its microstructure, which enhances its performance characteristics. This duplex structure provides excellent corrosion resistance against chloride pitting and crevice corrosion, particularly in corrosive environments.
Common Designations:
- UNS S32750
- UNS S32760
- EN 1.4410
- ASTM A240 (for plates/sheets)
- ASTM A182 (for flanges)
Super Duplex Chemical Composition (UNS S32750/S32760)
| Element | Typical Range (%) |
| Chromium (Cr) | 24 – 26 |
| Nickel (Ni) | 6 – 8 |
| Molybdenum (Mo) | 3 – 5 |
| Nitrogen (N) | 0.24 – 0.32 |
| Manganese (Mn) | ≤ 1.2 |
| Carbon (C) | ≤ 0.030 |
| Iron (Fe) | Balance |
Mechanical Properties of Super Duplex Steel
| Property | Value |
| Density | 7.8 g/cm³ |
| Tensile Strength | 770–850 MPa |
| Yield Strength | ≥ 550 MPa |
| Elongation | ≥ 15% |
| Hardness | ≤ 32 HRC |
| Impact Toughness | Excellent (even at -50°C) |
Where Is Super Duplex Stainless Steel Used?
| Industry | Applications |
| Oil & Gas | Subsea pipelines, heat exchangers, separators |
| Petrochemical | Pressure vessels, scrubbers, heat exchangers |
| Desalination | Evaporator tubes, brine heaters |
| Marine | Propeller shafts, hull reinforcements |
| Pulp & Paper | Digesters, bleach washers |
| Power Plants | Superheaters, water treatment lines |
Common Product Forms of Super Duplex Steel
| Form | Standard/Spec | Application |
| Super Duplex Stainless Steel Sheets and Plates | ASTM A240 | Structural panels, tanks, pressure vessels |
| Super Duplex Flanges | ASTM A182 F53/F55 | Piping connections in high-pressure systems |
| Super Duplex Pipes | ASTM A790 / A928 | Oil & gas piping, marine exhaust |
| Super Duplex Fittings | ASTM A815 | Pipe couplings, reducers, elbows |
| Super Duplex Round Bars | ASTM A479 | Shafts, valve stems, fasteners |
Super Duplex Grades Overview
| Grade | UNS Number | PREN | Common Use |
| S32750 | UNS S32750 | >41 | Oil & gas pipelines |
| S32760 | UNS S32760 | >42 | Desalination & marine |
| S39274 | UNS S39274 | >45 | Aggressive sour service |
| F53 | ASTM A182 | >40 | High-pressure flanges |
| F55 | ASTM A182 | >42 | Offshore and chemical plants |
Why Choose Super Duplex for Industrial Use?
1. Strength and Durability:
2. Corrosion Resistance:
3. Cost-Effective Over Life Cycle:
4. Easy to Maintain:
Super Duplex vs Other Stainless Steels
| Property | 316L | Duplex 2205 | Super Duplex S32750 |
| Yield Strength (MPa) | 290 | 450 | 550–600 |
| PREN | ~24 | ~35 | >41 |
| Chloride SCC Resistance | Moderate | Good | Excellent |
| Cost | Low | Medium | High (but value-rich) |
| Lifespan in Aggressive Environments | Short | Medium | Long |
Installation & Maintenance Tips
- Use matching filler metals (ER2594 or ENiCrMo-3) for welding.
- Avoid prolonged exposure above 250°C to prevent embrittlement.
- Post-weld heat treatment is not always required—it reduces fabrication costs.
- Use pickling and passivation for surface protection post-installation.
Need Super Duplex Stainless Steel Products?
Looking for certified super duplex stainless steel sheets, plates, flanges, or pipes?
Connect with verified Indian suppliers offering:
- ASTM and ASME standard-compliant materials
- Custom fabrication and cut-to-length services
- Export-ready packaging and logistics support
- Third-party inspection approvals
Enhance your industrial infrastructure with materials engineered for extreme environments and lasting performance.
Final Thoughts
Super Duplex Stainless Steel is not just another alloy—it’s an industrial workhorse designed for extreme environments where strength, corrosion resistance, and long-term value matter most. Whether you’re sourcing super duplex flanges for a petrochemical pipeline or easy to maintain super duplex pipe for a desalination plant, the material’s reliability pays dividends in performance and durability.
Always choose reputed super duplex stainless steel suppliers with certifications for your project compliance.