ASTM A335 P22 Serrated Fin Tube
I. Product Overview
ASTM A335 P22 serrated fin tubes are manufactured from P22
chromium-molybdenum alloy steel, a material specifically designed
for high-temperature and high-pressure service. With a nominal
composition of 2.25% chromium and 1% molybdenum, this grade
provides excellent resistance to oxidation, creep, and sulfur
attack at elevated temperatures. The tube utilizes a seamless base
pipe combined with helically wound, serrated (notched) fins that
are securely attached through high-frequency welding or an embedded
process. The serrated fin design significantly increases turbulence
and disrupts boundary layers, enhancing heat transfer efficiency
compared to plain fins. This construction maintains robust pressure
integrity while offering superior thermal performance in demanding
environments. Suitable for high-temperature heat exchangers,
boilers, heaters, and other critical pressure equipment, it can be
supplied in custom dimensions and fin configurations to meet
specific project requirements.
II. Chemical & Mechanical Properties
Base Tube Chemical Composition (%)
| Element | C | Si (max) | Mn | P (max) | S (max) | Cr | Mo |
| Range | 0.05–0.15 | 0.50 | 0.30–0.60 | 0.025 | 0.025 | 1.90–2.60 | 0.87–1.13 |
Mechanical Properties (Base Tube)
| Tensile Strength (min) | Yield Strength (min) | Elongation (min) |
| 415 MPa | 205 MPa | 30% |
III. Equivalent Material of P22
| ASTM | EN/DIN | UNS | JIS | GB | Common Name |
| A335 P22 | 10CrMo9-10 | K21590 | STPA24 | 12Cr2MoG | T22 / 2.25Cr-1Mo |
IV. Comparison: P22 vs P11 & P5 Alloy Steels
| Property | P22 (2.25Cr-1Mo) | P11 (1.25Cr-0.5Mo) | P5 (5Cr-0.5Mo) |
| Core Advantage | Best high-temp strength | Most cost-effective | Best corrosion resistance |
| Temp Limit | 565-600°C | 540-550°C | 600°C |
| Key Application | Power generation (high temp/pressure) | General industrial heat exchangers | Refineries (high sulfur) |
| Weldability | Good | Excellent | Good |
| Cost | Medium-High | Lowest | Medium-High |
V. Key Applications
● Power Generation Boilers: Superheater and reheater tubes, economizer sections, and
high-pressure steam lines in coal-fired and thermal power plants.
● Petrochemical & Refinery Heaters: Process heater coils, convection and radiant sections in crude,
vacuum, and reformer heaters.
● Heat Recovery Steam Generators (HRSG): Evaporator and superheater coils in gas turbine co
mbined-cycle units.
● High-Temperature Heat Exchangers: Waste heat recovery units, air preheaters, and process gas
coolers in chemical and metallurgical industries.
● Industrial Boilers & Steam Systems: High-pressure steam coils, boiler bank tubes, and steam
distribution piping in pulp/paper, textile, and food processing
plants.
