ASTM A335 P9 Spiral Finned Tube For Heat Transfer Equipments

We are the manufacturer of solid fin tube in China. As we have four production line of solid fin tube, we take great of our quality. We can customize the fin height, width, material and other parts according to customers' needs. Our spiral fin tube mainly used in power Plant, air preheaters, boiler, heat exchangers, inudustrial furnaces and other equipments to increase the heat exchange efficiency. And I am pleased to share following details about spiral HFW fin tube:

1. ASTM A335 P9 Base Tube

2. Manufacturing & Fabrication Processes
A. Base Tube Production

Process Flow:
Electric arc furnace → Vacuum degassing → Forging → Hot rolling (950–1050°C) → Heat treatment (normalizing at 950°C + tempering at (740–790°C) → NDT testing

Critical Steps: Precise heat treatment prevents grain coarsening and ensures uniform carbide distribution.

B. Fin Attachment via Welding

Welding Method:

GTAW (TIG) for root pass + SMAW (manual arc) for fill/cap.

Filler Materials:

TG-S9CM (TIG wire) and R707 (low-hydrogen electrode) for P9-carbon steel joints.

Pre-Weld Requirements:

Preheat: 250–350°C to prevent cracking.

Back purging with argon to shield against oxidation.

Post-Weld Treatment:

Stress relief: 300–350°C for 30 min (immediate post-heat).

Full PWHT at 740–790°C to reduce hardness and residual stresses.

3. A335 P9 Solid Fin Tube Advantage

Enhanced Heat Transfer: The solid fins provide a larger surface area, improving heat transfer efficiency in heat exchangers, economizers, and superheaters.
High Mechanical Strength: Made from ASTM A335 P9 alloy steel, these tubes withstand high pressures and temperature variations.
Durability and Reliability: Solid fin design offers increased structural integrity, resistance to damage, and longer service life.
Corrosion and Thermal Resistance: Suitable for high-temperature environments, resisting oxidation and thermal stresses.
Reduced Fouling: Smooth, continuous fin surfaces help minimize fouling and facilitate easier cleaning.
Cost-Effective: The robust design reduces maintenance costs and downtime over the operational lifespan.

4. A335 P9 Solid Fin Tube Application

Power Generation: Used in boiler superheaters, reheaters, and economizers to optimize heat transfer and improve efficiency.
Petrochemical & Refining: Employed in heat exchangers for process heating, cooling, and energy recovery.
Chemical Processing: Suitable for high-temperature process units requiring durable, efficient heat transfer solutions.
Industrial HVAC: Installed in large-scale heating systems requiring high thermal performance.
Marine and Off-shore: Applied in systems exposed to severe conditions with a need for high durability.