ASTM A335 P9 Alloy Steel HFW Solid Fin Tube
I. Product Overview
We manufacture this ASTM A335 P9 alloy steel fin tube from seamless ferritic alloy steel—specifically designed for high-temperature and high-pressure service. The P9 grade contains approximately 9% chromium and 1% molybdenum, offering excellent resistance to oxidation, corrosion, and creep under elevated temperatures.
The base tube is manufactured in accordance with ASTM A335, ensuring tight tolerances and consistent mechanical properties. Fins are attached using high-frequency welding (HFW), creating a robust metallurgical bond that enhances heat transfer efficiency while maintaining structural integrity under thermal cycling and mechanical stress.
This product is widely used in heat exchangers, boilers, superheaters, and process piping in industries such as petrochemical, power generation, and refining. Its extended surface area significantly improves thermal performance, making it an ideal choice for demanding heat recovery and heat exchange applications.
II. Chemical & Mechanical Properties
Base Tube Chemical Composition (%)
| Element |
C |
Mn |
P (max) |
S (max) |
Si |
Cr |
Mo |
| Range |
≤0.15 |
0.30–0.60 |
0.025 |
0.025 |
0.25–1.00 |
8.0–10.0 |
0.90–1.10 |
Mechanical Properties (Base Tube)
| Tensile Strength (min) |
Yield Strength (min) |
Elongation (min) |
| 415 MPa |
205 MPa |
30% |
III. Equivalent Material of ASTM A335 P9
| ASTM/AISI |
UNS NO |
EN |
ISO |
JIS |
GB |
| A335 P9 |
S50400 |
1.7386 |
X11CrMo9-1 |
STBA26 |
10Cr9Mo1VNb |
IV. Comparison: A335 P9 vs A335 P11 / P22 Alloy Steel
● High-Temperature Performance:
P9 offers higher creep strength and oxidation resistance than P11 or P22 due to its higher chromium and molybdenum content. It is particularly suited for service temperatures up to 650°C.
● Chemical Composition:
P9 contains 8–10% Cr and 0.9–1.1% Mo, while P11 has 1–1.5% Cr and 0.44–0.65% Mo, and P22 has 2–2.5% Cr and 0.87–1.13% Mo. The higher alloy content in P9 provides superior resistance to high-temperature corrosion.
● Applications:
P9 is preferred for severe service conditions such as refinery heaters, hydrocrackers, and high-temperature steam lines.
P11 and P22 are more commonly used in moderate-temperature applications like power plant piping and heat exchangers.
● Cost & Availability:
P9 is more expensive due to its higher alloy content and specialized heat treatment requirements.
P11 and P22 are more economical and widely available for general high-temperature applications.
V. Key Applications
● Power Generation: Superheater and reheater tubes in fossil fuel power plants, heat recovery steam generators (HRSG), and combined cycle systems.
● Petrochemical & Refining: High-temperature process piping, reformer units, hydrodesulfurization reactors, and delayed coker heaters.
● Industrial Boilers & Heaters: Convection sections in industrial boilers, thermal oil heaters, and waste heat recovery units.
● Metallurgical Industry: Heat exchangers in annealing furnaces, hot blast stoves, and gas cooling systems.
● Chemical Processing: High-temperature synthesis loops, catalytic reforming units, and ethylene cracking furnaces.
Product Tags:
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ASTM A335 P9 Seamless HFW Solid Fin Tube For Fired Heater Images
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