ASTM A335 P9 High Frequency Welded Finned Tube for Heat Recovery Steam Generators (HRSG)
ASTM A335 P9 High Frequency Welded (HFW) Finned Tubes are engineered for demanding heat transfer applications in Heat Recovery Steam Generators (HRSGs), where elevated temperatures, thermal cycling, and high-pressure operation require reliable performance. The combination of an ASTM A335 P9 alloy steel base tube and carbon steel (CS) fins provides an effective balance between mechanical strength and heat transfer efficiency.
Using high-frequency resistance welding, the fin is continuously bonded to the tube with a full metallurgical weld, creating excellent thermal conductivity while minimizing contact resistance. This manufacturing process also ensures consistent fin attachment, high production efficiency, and dependable long-term performance under cyclic operating conditions.
These finned tubes are widely supplied for new HRSG installations, combined-cycle power plants, and replacement projects where high heat recovery efficiency and extended service life are required.
- Manufactured using high-frequency resistance welding technology.
- ASTM A335 P9 alloy steel tube provides excellent high-temperature strength and oxidation resistance.
- Carbon steel fins offer an economical solution with efficient heat transfer performance.
- Continuous metallurgical bond between tube and fin improves thermal efficiency.
- Uniform fin geometry supports consistent airflow and heat exchange.
- Suitable for continuous operation under elevated pressure and temperature.
- Compatible with automatic tube bending, expansion, and header welding processes.
- Manufactured according to customer drawings or project specifications.
ASTM A335 P9 HFW finned tubes are commonly used in:
- Heat Recovery Steam Generators (HRSG)
- Combined Cycle Power Plants (CCPP)
- Gas Turbine Exhaust Heat Recovery Systems
- Economizers
- Boiler Heat Recovery Sections
- Waste Heat Boilers
- Industrial Heat Recovery Units
- Cogeneration Plants
- Petrochemical Heat Recovery Equipment
- Power Generation Boilers
| Item | Standard Range |
|---|---|
| Base Tube Outside Diameter | 25.4–63.5 mm (1"–2-1/2") |
| Tube Wall Thickness | 2.5–10.0 mm |
| Tube Length | Up to 24,000 mm |
| Fin Height | 8–25 mm |
| Fin Thickness | 0.8–2.0 mm |
| Fin Pitch | 3–12 FPI (approximately 2.1–8.5 mm pitch) |
| Bare Tube End | According to customer requirements |
| Fin Material | Carbon Steel (CS) |
| Tube Material | ASTM A335 P9 |
Custom dimensions are available upon request.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.15 max |
| Manganese (Mn) | 0.30–0.60 |
| Phosphorus (P) | 0.025 max |
| Sulfur (S) | 0.025 max |
| Silicon (Si) | 0.25–1.00 |
| Chromium (Cr) | 8.00–10.00 |
| Molybdenum (Mo) | 0.90–1.10 |
Chemical composition is based on ASTM A335 requirements.
| Property | Value |
|---|---|
| Tensile Strength | ≥ 585 MPa |
| Yield Strength | ≥ 415 MPa |
| Elongation | ≥ 20% |
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