ASTM A335 P22 Seamless Alloy Steel Studded Fin Tube For HVAC Systems
ASTM A335 P22 Seamless Studded Fin Tube
I. Product Overview
ASTM A335 P22 seamless studded fin tubes are designed for demanding applications that require maximum heat transfer under high temperature, high pressure, and high-fouling conditions. Made from P22 chromium-molybdenum alloy steel (2.25Cr-1Mo), the tubes offer outstanding resistance to oxidation, creep, and sulfur corrosion at elevated temperatures.
Unlike conventional helical fins, this tube features a series of individually welded studs (pins) on its outer surface. This studded design promotes intense turbulence, disrupts thermal boundary layers, and helps minimize ash or particulate buildup—resulting in higher, more sustainable thermal efficiency. The seamless base tube provides strong pressure containment, while the welded studs ensure a solid, integral bond.
Well-suited for radiant sections of heaters, boiler water walls, and severe-service waste heat recovery units, these tubes can be customized in dimensions and stud layout (pitch, height, diameter) to meet specific process needs.
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 | 2.25Cr-1Mo / T22 |
IV. Comparison: P22 Studded Fin Tube vs. P11 & P91 Alloys
|
Property / Grade |
P11 |
P22 |
P91 |
|
Material Type |
Heat-resistant ferritic alloy steel |
Ferritic alloy steel (seamless tube) |
Martensitic alloy steel |
|
Key Characteristics |
Excellent corrosion & oxidation resistance; Good weldability. |
High elasticity & tensile strength; Crack-resistant; Good thermal conductivity. |
High creep strength & thermal resistance at elevated temperatures. |
|
Typical Applications |
Power generation, chemical plants, high-pressure & high-temperature environments. |
High-pressure steam systems, boilers, heat exchangers in petrochemical plants. |
State-of-the-art power generation systems, advanced boilers, ultra-supercritical steam turbines. |
|
Chemical Composition (Key) |
C: 0.05-0.15% |
(Focused on physical properties) |
Cr: 8.00-9.50% |
|
Mechanical Properties (Min.) |
Tensile Strength: ≥415 MPa |
Tensile Strength: ≥415 MPa Yield Strength: ≥205 MPa |
Tensile Strength: ≥585 MPa |
V. Key Applications
● Refinery & Petrochemical Heaters: Radiant wall and shield tubes in cracking furnaces, reformer heaters, and coker heaters exposed to direct flame impingement and coking.
● Power Generation Boilers: Membrane water-walls in coal-fired, biomass, and waste-to-energy boilers to maximize heat absorption and minimize slagging.
● Syngas & Process Gas Coolers: Quench coolers and waste heat boilers in chemical plants (e.g., ethylene, methanol) handling dusty or fouling gases.
● Carbon Black & Incineration Plants: Heat exchanger tubes in reaction furnaces and off-gas cooling sections with heavy particulate loading.
● High-Temperature Fluidized Bed Systems: In-bed heat exchanger tubes requiring abrasion resistance and optimized heat pick-up.
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