ASTM A335 P22 Alloy-Steel Pipe With AS Fin Material HFW Solid Fin Tube, High-Temperature Service

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ASTM A335 P22 Alloy-Steel Pipe With AS Fin Material HFW Solid Fin Tube, High-Temperature Service

This product is a high-performance composite pipe designed explicitly for extreme high-temperature and high-pressure service. The base pipe is manufactured from ASTM A335 Grade P22 chromium-molybdenum alloy steel, known for its excellent creep resistance and high-temperature strength. The fins are also made from an alloy steel (AS - Alloy Steel) material and are integrally bonded to the base pipe via the High-Frequency Welding (HFW) process, forming a solid fin structure. This "alloy steel base pipe to alloy steel fin" combination, utilizing similar or matching materials, ensures uniform thermal expansion, superior resistance to high-temperature oxidation, and exceptional structural integrity and strength throughout the entire component under elevated temperatures. This product is primarily used in highly demanding applications such as boiler superheaters, reheaters, and high-temperature heat exchangers in the petrochemical industry, where material performance is critical.

1.Chemical & Mechanical Properties

Mechanical Properties

ASTM A335 P22 Base Tube

2. Key Features

• All-Alloy Steel Construction for Superior High-Temperature Performance

The base tube (P22) and fins (AS) are both alloy steel, ensuring matched performance of the entire assembly at high temperatures. It can operate continuously at up to 595°C and withstand short-term peak temperatures of ~650°C, far exceeding the limits of carbon steel finned tubes (typically restricted to ~480°C).

• High-Frequency Welding (HFW) for Optimal Heat Transfer & Reliability

The HFW process creates a metallurgical bond between the fin and base tube. This bond offers minimal contact resistance, ensuring maximum heat transfer efficiency, and provides high mechanical strength, excellent resistance to thermal shock and fatigue, eliminating the risk of fin loosening or detachment.

• Uniform Thermal Expansion and Exceptional Structural Integrity

The base tube and fin materials have similar coefficients of thermal expansion, allowing them to expand and contract in sync during repeated heating and cooling cycles, generating low thermal stress. This significantly reduces the risk of weld cracking and guarantees long-term structural integrity and reliability in demanding service conditions.

• Strong High-Temperature Oxidation Resistance and Long Service Life

The chromium (Cr) in P22 forms a dense, protective chromium oxide layer. The alloy steel fins also possess excellent oxidation resistance, enabling the entire finned tube (not just the base tube) to resist high-temperature scaling and corrosion, significantly extending equipment service life.

• Unbeatable Cost-Effectiveness in High-Temperature Applications

Compared to using more advanced full-alloy materials (e.g., P91, stainless steel) for the entire finned tube, this solution significantly reduces cost while meeting demanding high-temperature requirements. It represents the optimal balance between performance and price, positioned between carbon steel and premium alloy finned tubes.

3. Key Applications

Power Station Boiler Hot Sections: Superheater, Reheater

Petrochemical & Oil Refining: high-temperature heat exchangers, fluid catalytic cracking (FCC)

Industrial Boilers & Incinerators: heat recovery steam generators (HRSG)

Metallurgical Industry

HFW Solid Fin Tube vs. HFW Serrated Fin Tube

Solid Fin: Robust structure, superior resistance to temperature, corrosion, and abrasion. Ideal for harsh conditions.

Serrated Fin: Efficiency first. Dramatically enhances heat transfer via increased area and turbulence, but less robust and prone to fouling/corrosion.

Key Difference: Choose Solid for durability & reliability; choose Serrated for maximum efficiency in clean environments.