ASTM A789 UNS S39277 Duplex Stainless Steel Tubes
ASTM A789 UNS S39277 is a high-performance duplex stainless steel grade designed for demanding applications that require exceptional strength, superior corrosion resistance, and excellent stress corrosion cracking resistance. The high chromium, molybdenum, and nitrogen content makes UNS S39277 ideal for aggressive environments such as seawater systems, chemical processing, petrochemical plants, and offshore structures.
This duplex stainless steel grade offers a balanced microstructure of austenite and ferrite, providing higher mechanical strength than standard stainless steels along with better pitting and crevice corrosion resistance. UNS S39277 Tubes under ASTM A789 are widely used for heat exchangers, hydraulic systems, desalination plants, and high-pressure services.
Key Features
- High resistance to pitting, crevice corrosion, and chloride stress corrosion cracking
- Excellent performance in seawater and chloride-rich environments
- Good weldability and formability
- Suitable for high-pressure and high-temperature applications
- Designed for enhanced durability and long service life
Equivalent Grades of UNS S39277
| Standard | Equivalent Grade |
|---|---|
| UNS | S39277 |
| EN | 1.39277 (Approx.) |
| WNR | Available on request |
| Other Trade Names | Super Duplex Variant |
Available Sizes
| Parameter | Range |
|---|---|
| Outside Diameter (OD) | 6 mm to 219 mm |
| Wall Thickness | 0.5 mm to 20 mm |
| Length | Up to 12 meters |
| Customized Sizes | Available upon request |
ASTM A789 UNS S39277 Chemical Composition
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 4.5 |
| Nitrogen (N) | 0.30 – 0.45 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 |
| Carbon (C) | ≤ 0.030 |
| Phosphorus (P) | ≤ 0.030 |
| Sulfur (S) | ≤ 0.020 |
| Iron (Fe) | Balance |
Grade UNS S39277 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 750 MPa |
| Yield Strength | ≥ 550 MPa |
| Elongation | ≥ 25% |
| Hardness | ≤ 290 HBW |
Grade UNS S39277 Physical Properties
| Property | Value |
|---|---|
| Density | 7.80 g/cm³ |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity | ~15 W/m·K |
| Electrical Resistivity | 0.85 µΩ·m |
| Melting Range | 1350–1450°C |
Types of ASTM A789 UNS S39277 Tubes
- Seamless Tubes
- Welded Tubes
- ERW Tubes
- EFW Tubes
- Heat Exchanger Tubes
- Instrumentation Tubes
- Hydraulic Tubes
- U-Bend Tubes
- Coiled Tubes
Applications
- Offshore Platforms
- Marine & Seawater Systems
- Desalination Plants
- Chemical & Petrochemical Processing
- Oil & Gas Refineries
- Heat Exchangers and Condensers
- Pulp & Paper Industry
- Power Generation Plants
- High-pressure Hydraulic Lines
- Structural and Mechanical Components




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