ASTM A269 TP347 Stainless Steel Tubes (UNS S34700)
ASTM A269 TP347 (UNS S34700) Stainless Steel Tubes are stabilized austenitic stainless steel tubes alloyed with niobium (columbium), offering excellent resistance to intergranular corrosion after welding and high-temperature exposure. TP347 is designed to perform in environments where temperatures exceed 425°C (800°F), making it superior to TP304 and TP321 in high-temperature creep strength and stress rupture resistance. These tubes are widely used in the chemical processing, refinery, aerospace, and high-temperature piping industries.
Key Features
- Superior Intergranular Corrosion Resistance due to niobium (Nb/CB) stabilization.
- Enhanced High-Temperature Strength especially above 425°C.
- Excellent Stress Rupture & Creep Resistance compared to 304/321 grades.
- High Oxidation Resistance up to 870°C (1600°F).
- Improved Weldability without the risk of carbide precipitation.
- Excellent Mechanical Strength in elevated as well as sub-zero temperatures.
- Ideal for High-Temperature Chemical & Petrochemical Applications.
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | S34700 |
| WNR | 1.4550 |
| EN | X6CrNiNb18-10 |
| BS | 347S31 |
| JIS | SUS 347 |
Available Sizes
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Outer Diameter (OD): 3.2 mm – 114.3 mm
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Wall Thickness: 0.5 mm – 12 mm
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Length: Up to 12 meters
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Custom sizes available upon request
ASTM A269 TP347 Chemical Composition
| Element | % Composition |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 0.75 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.0 – 19.0 |
| Nickel (Ni) | 9.0 – 13.0 |
| Niobium + Tantalum (Nb + Ta) | 10 × C to 1.0 |
| Nitrogen (N) | ≤ 0.10 |
ASTM A269 TP347 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Proof) | ≥ 205 MPa |
| Elongation | ≥ 35% |
| Hardness (Rockwell B) | ≤ 92 HRB |
| Density | 8.0 g/cm³ |
ASTM A269 TP347 Physical Properties
| Property | Value |
|---|---|
| Melting Point | 1400 – 1425°C |
| Thermal Conductivity | 16.3 W/m-K (at 100°C) |
| Electrical Resistivity | 0.72 µΩ-m |
| Thermal Expansion | 16.6 × 10⁻⁶ /°C |
| Modulus of Elasticity | 193 GPa |
Types of ASTM A269 TP347 Tubes
- Seamless Stainless Steel Tubes
- Welded Stainless Steel Tubes
- Bright Annealed (BA) Tubes
- Electropolished Tubes
- Heat Exchanger Tubes
- Condenser Tubes
- Instrumentation Tubes
- Capillary Tubes
- U-Bent Tubes
- Hydraulic Tubes
Applications
- Chemical Processing Equipment
- Oil & Gas Refinery Units
- Heat Exchangers & Condensers
- High-Temperature Furnace Components
- Power Generation Boiler Tubing (Non-Pressure)
- Exhaust Manifolds & Hot Gas Ducts
- Food Processing & Pharmaceutical Equipment
- Aerospace High-Temperature Components
- Thermal Oxidizers & Petrochemical Piping
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