Common Base Tube Materials for Extruded Finned Tubes

2026-04-30Leave a message

Base Tube Materials for Extruded Finned Tubes | Lordfintube

Common Base Tube Materials for Extruded Finned Tubes

The efficiency and longevity of a heat exchanger depend heavily on the synergy between the fin and the base tube. Extruded finned tubes, often referred to as "bimetallic" finned tubes, are unique because the outer aluminum muff is cold-rolled onto an inner base tube.

This process creates a mechanical bond that provides 100% contact, ensuring excellent heat transfer. At Lordfintube, we specialize in integrating various alloys to meet rigorous industrial standards.

Dominant Base Tube Materials in Modern Engineering

Choosing the right substrate is a balance between thermal conductivity, mechanical strength, and cost-effectiveness.

Carbon Steel (ASTM A179, A192, SA210)

The most common choice for air-cooled heat exchangers. It offers high structural integrity and is highly cost-effective for non-corrosive environments.

Stainless Steel (SS304, SS316L, SS321)

When the internal fluid is corrosive or requires high hygiene standards (food/chemical), stainless steel is preferred. SS316L offers superior resistance to pitting.

Copper & Alloys (C12200, C70600 CuNi 90/10)

Known for unrivaled thermal conductivity, frequently used in marine environments or HVAC systems where salt-air corrosion is a concern.

Alloy Steel (ASTM A213 T11, T22)

Specifically utilized for high-temperature power plant applications where creep resistance is vital for long-term reliability.

The Cold-Rolling Manufacturing Process

The production of an extruded finned tube involves placing an aluminum tube (sleeve) over the selected base tube. This assembly passes through three sets of multi-disc rollers. The rollers "extrude" the aluminum into high fins while simultaneously compressing the sleeve onto the base tube.

This mechanical bond is so tight that it prevents atmospheric corrosion at the interface, a common failure point in "L" or "KL" type fins. Because the base tube is never exposed to the external cooling medium, its primary job is to handle the internal pressure and process fluid chemistry.

Cold-Rolling Extrusion Visualization
Mechanical Bonding & Fin Formation

Technical Specifications

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Base Tube OD: 15.88mm to 50.8mm

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Fin Height: Up to 16mm

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Fin Pitch: 7 to 11 fins per inch (FPI)

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Max Length: Up to 18 meters for industrial applications

Industry Applications

O&G

Oil & Gas

PWR

Power Gen

MAR

Marine

BIO

Food/Pharma

Selecting the optimal base tube material extends equipment lifecycle while maintaining peak thermal efficiency.

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