ASTM A789 UNS S39274 Super Duplex Stainless Steel Tubes
ASTM A789 UNS S39274 Super Duplex Stainless Steel Tubes are engineered for highly corrosive and high-pressure service conditions. UNS S39274 is a premium super duplex grade enriched with chromium, molybdenum, nitrogen, and tungsten, offering exceptional pitting and crevice corrosion resistance, especially in chloride-rich and seawater environments.
These tubes deliver superior strength, structural stability, and long-term service performance, making them ideal for offshore engineering, desalination plants, chemical processing, power generation, and petrochemical industries. With outstanding durability and reduced maintenance requirements, S39274 provides a reliable solution for the most demanding industrial applications.
Key Features
- Exceptional pitting and crevice corrosion resistance
- High tensile and yield strength suitable for severe environments
- Excellent resistance to chloride stress corrosion cracking
- Enhanced thermal conductivity and low thermal expansion
- Suitable for high-pressure, high-temperature applications
- Long-lasting durability with superior metallurgical stability
Equivalent Grade
| Standard |
Grade |
| UNS |
S39274 |
| EN / DIN |
1.4658 |
| Trade Name |
Hyper Duplex Grade (Manufacturer Specific) |
| ISO |
Equivalent Super Duplex Category |
ASTM A789 UNS S39274 Chemical Composition
| Element |
Percentage (%) |
| Chromium (Cr) |
25.0 – 27.0 |
| Nickel (Ni) |
6.5 – 8.5 |
| Molybdenum (Mo) |
3.5 – 4.5 |
| Tungsten (W) |
1.0 – 2.0 |
| Nitrogen (N) |
0.30 – 0.40 |
| Manganese (Mn) |
≤ 1.0 |
| Silicon (Si) |
≤ 1.0 |
| Carbon (C) |
≤ 0.03 |
| Phosphorus (P) |
≤ 0.03 |
| Sulfur (S) |
≤ 0.01 |
| Iron (Fe) |
Balance |
UNS S39274 Mechanical Properties
| Property |
Value |
| Tensile Strength |
≥ 800 MPa |
| Yield Strength (0.2% Proof) |
≥ 550 MPa |
| Elongation |
≥ 25% |
| Hardness |
≤ 300 HB |
UNS S39274 Physical Properties
| Property |
Value |
| Density |
7.80 g/cm³ |
| Thermal Conductivity |
14 W/m·K |
| Electrical Resistivity |
0.80 µΩ·m |
| Elastic Modulus |
200 GPa |
| Melting Point |
1350 – 1450°C |
Type of UNS S39274 Tubes
- Seamless Super Duplex Tubes
- Welded Super Duplex Tubes
- ERW Tubes
- EFW Tubes
- Heat Exchanger Tubes
- Hydraulic Tubes
- Instrumentation Tubes
Application
- Offshore Oil & Gas Structures
- Subsea Pipelines & Flowlines
- Marine & Seawater Cooling Systems
- Desalination Plants
- Chemical & Petrochemical Equipment
- Pulp & Paper Processing
- Heat Exchangers & Condensers
- Power Plant Systems
- High-Chloride and High-Pressure Environments
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