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.

Product Features

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.

Common Applications

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

Typical Size Range

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.

Chemical Composition of ASTM A335 P9 Base Tube

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.

Mechanical Properties of ASTM A335 P9 Base Tube

Property	Value
Tensile Strength	≥ 585 MPa
Yield Strength	≥ 415 MPa
Elongation	≥ 20%

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Beslagen Buis

Solid Fin Tube

Getande Finned Buis

G Fin Tube ingebed

Uitgedreven Vinbuis

Wondenvinnenbuis

Lange vinnenbuis

Vierkantvinnenbuis

Langeafstandsvinnenbuis

Verbeterde warmteoverdrachtbuis

Steun van de vinnenbuis

Terugkeerkromming

Warmtewisselaar

De Buis van de roestvrij staalWarmtewisselaar

De duplexbuis van de Roestvrij staalWarmtewisselaar

Super-duplex-warmtewisselaar van roestvrij staal

Nickel legering staal warmtewisselaar buis

Ruimtewisselaar van koperen staal

Titanium legering staal warmtewisselaar buis

Lijststaal warmtewisselaar

U BEND HETTE-UITwisselbuis

De Buizen van de KoolstofstaalWarmtewisselaar

Boilerbuis

Nikkellegeringsstaalketelbuis

Roestvrijstalen ketelbuis

Duplex ketelbuis van roestvrij staal

De Boilerbuis van het legeringsstaal

De buis van de koolstofstaalboiler

Verwarmingsonderdelen

Keerschot

Tubesheet

details van de producten

Beslagen Buis

Solid Fin Tube

Getande Finned Buis

G Fin Tube ingebed

Uitgedreven Vinbuis

Wondenvinnenbuis

Lange vinnenbuis

Vierkantvinnenbuis

Langeafstandsvinnenbuis

Verbeterde warmteoverdrachtbuis

Steun van de vinnenbuis

Terugkeerkromming

Warmtewisselaar

De Buis van de roestvrij staalWarmtewisselaar

De duplexbuis van de Roestvrij staalWarmtewisselaar

Super-duplex-warmtewisselaar van roestvrij staal

Nickel legering staal warmtewisselaar buis