Classification of Finned Tubes and Materials and Specifications That Can Be Produced

What is a finned tube?

Finned tubes are heat exchange elements composed of metal tubes and fins. The fins are usually fixed to the surface of the metal tube by welding, rolling, winding, etc., forming a series of raised parts, which are the fins. The main function of finned tubes is to increase the heat exchange area, promote the rapid transfer of heat, and achieve efficient and energy-saving heat exchange effects.

Finned tubes can be systematically classified based on manufacturing processes, fin geometry, and material homogeneity, providing versatility for industrial applications like heat exchangers and boilers. Below is a structured overview of the key classifications, with all types expressed in English for clarity.

By Manufacturing Process

This classification focuses on how the fins are attached or formed to the base tube:

• ‌Extruded fin tube‌: Fins created through die extrusion, ideal for lightweight designs
• ‌Welded fin tube‌: Includes subtypes like high-frequency welded and submerged arc welded, offering strong joints for high-pressure environments
• ‌Rolled fin tube‌: Formed via rolling techniques, ensuring uniform fin distribution
• ‌Set-mounted fin tube‌: Assembled by mounting fins onto the tube surface, commonly for modular systems
• ‌Cast fin tube‌: Produced by casting methods, suitable for complex shapes
• ‌Tension-wrapped fin tube‌: Fins wound under tension for secure bonding
• ‌Embedded fin tube‌: Fins mechanically embedded into the tube, enhancing durability
• ‌Wound fin tube‌: Spirally wound fins around the tube, optimizing surface area

By Fin Geometry

This categorizes tubes based on the shape and orientation of the fins:

• ‌Square finned tube‌: Fins with a square profile, improving turbulence in flow
• ‌Circular finned tube‌: Circular cross-section fins, used for uniform heat distribution
• ‌Spiral finned tube‌: Helical fins wrapped around the tube, enhancing fluid mixing
• ‌Longitudinal finned tube‌: Fins aligned parallel to the tube axis, reducing flow resistance
• ‌Corrugated finned tube‌: Wavy or ripple-shaped fins, increasing contact area
• ‌Helical serrated finned tubes‌: Notched fins to disrupt boundary layers, ideal for dusty environments
• ‌Pin finned tube‌: Short, pin-like projections for localized heat transfer
• ‌Plate fin tube‌: Flat plate-style fins, often used in compact heat exchangers
• ‌Inner finned tube‌: Fins inside the tube bore, boosting internal heat exchange

By Material Homogeneity

This division considers whether the base tube and fins share the same material:

• ‌Single-metal finned tube‌: Base and fins made of identical material, such as all-aluminum or all-steel, for consistent thermal properties

This classification system integrates industry standards to guide selection based on operational needs like corrosion resistance or thermal efficiency. For instance, spiral finned tubes are prevalent in waste heat recovery, while embedded types suit HVAC systems.

Here’s a structured table summarizing the production processes, materials, and typical specifications of finned tubes:

‌Notes‌:

• ‌Extruded tubes‌: Standard OD starts from 25mm (por exemplo,, DN25)2, while HVAC/copper tubes may use smaller diameters (8–32mm).
• ‌Large diameters‌: Up to DN200 (200mm) for industrial applications.
• ‌Custom sizes‌: Laser-welded and rolled tubes often follow project-specific requirements.