Extruded Finned Tube

What Is an Extruded Finned Tube?

Extruded finned tubes, base material ASTM A179, fin material aluminum 6063.

An extruded finned tube is a high‑efficiency heat transfer tube widely used in heat exchangers. It is manufactured by mechanically extruding an outer metal sleeve over a base tube so that the sleeve forms integral fins that are tightly bonded to the tube wall. Because the fins and tube are metallurgically and mechanically bonded, extruded fin tubes provide excellent heat transfer performance, high fin efficiency, and long service life.

Compared with other finned tube types (such as L‑type, LL‑type, or G‑type fin tubes), extruded fin tubes offer superior resistance to corrosion, better mechanical strength, and stable performance under demanding operating conditions.

Manufacturing Process for Extruded Finned Tubes

The extruding equipment for the production of extruded finned tubes.

The manufacturing process of extruded fin tubes is a precise and highly controlled mechanical operation designed to ensure excellent bonding and thermal performance. First, the base tube—commonly carbon steel, stainless steel, copper, or alloy steel—is thoroughly cleaned and inspected to ensure surface quality and dimensional accuracy. Next, a thick outer sleeve, usually aluminum or copper, is assembled tightly over the base tube. The tube assembly is then processed on a specialized cold extrusion machine, where extremely high pressure causes the outer sleeve material to plastically deform and flow, forming continuous fins while being simultaneously pressed into the surface of the base tube. During this cold-working process, the fins become an integral part of the tube structure, achieving a 100% mechanical bond with minimal thermal resistance between fin and tube. After extrusion, the finned tubes are cut to the required lengths, straightened, and subjected to dimensional inspection, fin integrity checks, and bonding quality control to ensure consistent performance and long-term reliability.

Classification of Extruded Fin Tubes

Extruded finned tubes are mainly classified by material combination. In commercial supply, the base tube and fins are usually made of different materials to balance pressure resistance, corrosion performance, heat transfer efficiency, and cost. Same-material extruded fin tubes are available but are typically limited to specific applications.

• Carbon Steel Tube + Aluminum Fins: Base tube according to ASTM A179 / ASME SA179 or ASTM A192, with aluminum fins made from Al 1060 / AA 3003 / AA 6063 in accordance with ASTM B221. This is the most economical solution for air coolers, economizers, and industrial heat exchangers.
• Stainless Steel Tube + Aluminum Fins: Base tube manufactured to ASTM A213 / ASME SA213 (TP304 / TP316), combined with aluminum extruded fins per ASTM B221, offering improved corrosion resistance for petrochemical and industrial applications.
• Stainless Steel Tube + Stainless Steel Fins: Both tube and fins made from stainless steel grades such as 304 or 316, based on ASTM A213 / ASME SA213, suitable for high-temperature and highly corrosive service conditions.
• Copper or Copper-Nickel Tube + Aluminum or Copper Fins: Base tubes conforming to ASTM B111 (CuNi 90/10 or 70/30) or pure copper standards, with aluminum or copper fins, commonly used in marine and seawater heat exchangers.
• All-Aluminum One-Piece Extruded Finned Tubes: Integral finned tubes fully extruded from aluminum alloy such as AA 6063, manufactured according to ASTM B221, widely applied in HVAC systems, radiators, and lightweight heat exchangers.

Applications and Industrial Uses

Extruded finned tubes are an essential component in industrial heat transfer systems. Known for their high thermal efficiency, strong fin-to-tube bonding, and long service life, they are widely used across multiple industries where reliable heat transfer is critical.

• Heat Exchangers: Extruded fin tubes are extensively applied in shell-and-tube heat exchangers. The integral fin design ensures superior heat transfer efficiency and mechanical strength, delivering stable performance in long-term operations under high temperature and high pressure conditions.
• Air Coolers: Air-cooled heat exchangers benefit from the large external surface area of extruded fin tubes. They are ideal for oil coolers, gas coolers, and industrial air cooling systems, providing efficient heat dissipation and consistent thermal performance.
• Power Plants: Power generation facilities use extruded fin tubes in condensers, economizers, and auxiliary cooling equipment. Their robust construction and high thermal conductivity make them reliable for continuous operation and critical power plant applications.
• Petrochemical Industry: In refineries and chemical plants, extruded fin tubes are used in process heaters, gas coolers, and heat recovery units. They perform effectively under high temperatures, high pressures, and corrosive environments, ensuring safe and efficient industrial processes.
• HVAC Systems: Extruded fin tubes are widely used in HVAC systems, including air handling units, chillers, and refrigeration condensers. Their compact design, excellent thermal conductivity, and durability improve overall system efficiency while reducing equipment size.
• Waste Heat Recovery: Extruded fin tubes are ideal for waste heat recovery systems, allowing industries to reclaim heat from exhaust gases. This application enhances energy efficiency, reduces operating costs, and supports sustainable industrial operations.