ASTM A213 TP348 Stainless Steel Tubes ( UNS S34800 )
ASTM A213 TP348 Stainless Steel Tubes (UNS S34800) are stabilized austenitic stainless steel tubes designed specifically for high-temperature, high-pressure service in heat exchanger, boiler, and superheater systems. TP348 is similar to TP347, but with a more controlled and balanced composition, offering enhanced resistance to intergranular corrosion, especially after welding or exposure to temperatures between 425°C and 870°C—zones prone to carbide precipitation.
The stabilization is achieved through the addition of columbium/niobium, which binds carbon and prevents chromium carbide formation. This makes TP348 an ideal choice for environments involving high-temperature steam, corrosive flue gases, and thermal cycling conditions. With excellent strength, oxidation resistance, creep performance, and surface finish, TP348 seamless tubes ensure long service life in energy, chemical, and petrochemical sectors. These tubes are widely preferred for demanding industrial applications where stable performance under continuous heating is critical.
Key Features
- Niobium-stabilized to prevent carbide precipitation
- Superior resistance to intergranular corrosion
- Excellent creep strength and stress-rupture resistance
- High-temperature oxidation and scaling resistance
- Smooth internal surface for efficient heat transfer
- Excellent weldability and fabrication performance
- Suitable for continuous steam and high-temperature operations
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | S34800 |
| WNR | 1.4551 |
| EN | X6CrNiNb18-10 (Variant) |
Available Sizes
- OD: 6 mm to 114.3 mm
- Wall Thickness: 1.0 mm to 12.7 mm
- Length: Single Random, Double Random & Custom Cut Lengths
ASTM A213 TP348 Chemical Composition
| Element | % |
|---|---|
| Carbon (C) | ≤0.08 |
| Chromium (Cr) | 17.0–19.0 |
| Nickel (Ni) | 9.0–13.0 |
| Niobium/Columbium (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 TP348 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥515 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥35% |
| Hardness | ≤192 HB |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ |
| Melting Point | 1398–1454°C |
| Thermal Conductivity | 16 W/m-K |
| Elastic Modulus | 193 GPa |
| Electrical Resistivity | 0.73 µΩ-m |
Types of ASTM A213 TP348 Tubes
- Seamless Boiler Tubes
- Seamless Superheater Tubes
- Heat Exchanger Tubes
- Pressure Tubes
- Polished Instrumentation Tubes
Applications
- Power Plant Boilers & Reheaters
- High-Temperature Superheaters
- Petrochemical Furnace Tubes
- Thermal & Chemical Processing Units
- Heat Exchanger Assemblies
- Refinery Steam and Heater Lines
- Industrial High-Pressure Piping Systems
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