ASTM A213 TP347H (UNS S34709) Stainless Steel Seamless Tube
ASTM A213 TP347H Stainless Steel Tube (UNS S34709) are high-performance, high-carbon austenitic stainless steel tubes specially designed for elevated-temperature and high-pressure service. As the “H” designation indicates, TP347H contains an increased carbon percentage, enhancing creep resistance, stress-rupture strength, and structural stability during prolonged exposure to temperatures beyond 600°C. The grade is stabilized with niobium/columbium, which prevents carbide precipitation, enabling superior intergranular corrosion resistance, especially during welding and continuous heating cycles.
These tubes are widely used in demanding industrial setups such as superheaters, boilers, petrochemical heaters, furnace tubes, and heat-exchange systems. With excellent resistance to oxidation, sulfidation, and thermal fatigue, TP347H seamless tubes ensure long-term durability in harsh, high-temperature environments. They offer exceptional dimensional precision, smooth internal surfaces for improved heat transfer, and excellent mechanical properties, making them a trusted choice across various heavy industries.
Key Features
- High-carbon content ensures superior creep and rupture strength
- Niobium/columbium stabilization prevents carbide formation
- Outstanding thermal stability and oxidation resistance
- Supports continuous service in high-temp & high-pressure environments
- Smooth interior enhances heat transfer efficiency
- Excellent weldability and formability for fabrication
- Ideal for long-term exposure to temperatures up to 870°C
Equivalent Grades
| Standard | Grade |
|---|---|
| EN | X6CrNiNb18-10 (High Carbon Variant) |
| WNR | 1.4912 |
| UNS | S34709 |
Available Sizes
- OD: 6 mm to 101.6 mm
- Wall Thickness: 1.0 mm to 12.7 mm
- Length: Up to 12 meters (custom available)
ASTM A213 TP347H Chemical Composition
| Element | % |
|---|---|
| Carbon (C) | 0.04–0.10 |
| Chromium (Cr) | 17–19 |
| Nickel (Ni) | 9–13 |
| Niobium (Nb/Cb) | 10×C min – 1.00 max |
| Manganese (Mn) | ≤2.00 |
| Silicon (Si) | ≤0.75 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.030 |
| Nitrogen (N) | ≤0.10 |
ASTM A213 TP347H Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥550 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥35% |
| Hardness | ≤192 HB |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ |
| Melting Range | 1398–1454°C |
| Thermal Conductivity | 16 W/m-K |
| Elastic Modulus | 193 GPa |
| Electrical Resistivity | 0.73 µΩ-m |
Type of ASTM A213 TP347H Tube
- Seamless Boiler Tubes
- Seamless Superheater Tubes
- Heat Exchanger Tubes
- Pressure Tubes
Applications
- Power Plant Boilers
- Superheaters & Reheaters
- Petrochemical Heaters
- Refinery Furnace Tubes
- High-Temperature Steam Lines
- Chemical & Thermal Processing Units
- Heat Exchanger Assemblies
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