L-Foot Finned Tube (Alloy Steel Spiral-Wound) for Heat Exchangers

Material

This product is a finned heat-exchanger tube where an alloy steel base (core tube) is wound helically with a fin strip whose foot is shaped into an “L” profile, hence the term “L-foot fin”. The fins are under tension, tightly pressed onto the core tube surface, forming a continuous spiral fin around the outer circumference.

Specifications

Typical ranges and features:

• Core tube material: seamless alloy steel (e.g., grades such as ASTM A213 T11, T22; EN 13CrMo4-5; JIS STBA22; GB 12Cr1MoVG)

• Outer diameter (OD) of base tube: about 16 to ~50.8 mm (≈⅝″ to 2″) for many air-cooler finned tubes.

• Fin material: typically aluminium or copper strip, sometimes steel, wound in an L-foot geometry.

• Fin height: up to ~16.5 mm (max) in many cases.

• Fin thickness: about 0.4 mm to 0.6 mm typical for aluminium fin strips.

• Fin pitch (spacing): minimum around 2.1 mm (≈12 FPI) and up depending on design.

• Typical tube length: up to ~18,000 mm (18 m) for some manufacturers.

• Operating temperature (fin-side): up to ~150-230 °C typical for L-foot finned tubes.

Key Features

• The L-foot fin geometry ensures the fin foot lies flat on the tube surface, improving thermal contact and thus enhancing heat transfer.

• The spiral winding provides continuous coverage around the tube, dramatically increasing the external surface area available for heat transfer compared to bare tubes.

• The design allows the fin to act as a protective cover for the tube wall (on the ambient/external side), offering some corrosion protection from the air side.

• Because the fins are tension-wound rather than extruded into grooves, the core tube can be thinner or use more expensive alloy steel with less modification of the base tube.

Our Advantages

1. Will the fins remain firmly attached under thermal cycling and high-velocity air vibration?
Our L-foot finned tubes use controlled tension in the fin strip winding to ensure tight foot contact on the tube and minimize loosening under start-stop cycling, vibration, or thermal shocks.

2. Is the L-foot fin the right choice (vs LL, KL, embedded types) for my duty?
Yes—if your air-side fin temperature is moderate (e.g., up to ~230 °C) and you want a cost-effective solution with high surface area, the L-foot design offers excellent performance. For more severe duties (higher temperatures, very aggressive atmospheres) we can advise upgraded fin types (LL/KL) or alternate materials.

3. How about corrosion resistance, air-side life, and maintenance?
The fin serves to shield the tube wall, reducing direct exposure of the tube to ambient air and therefore reducing corrosion potential. Also, by increasing heat-transfer efficiency, fewer tubes are required for the same duty, reducing bundle volume and associated structure/fan cost.

4. Traceability and material-grade compliance for high-temperature service?
Our core tubes are sourced using recognized standards (ASTM/EN/JIS/GB) with full mill test certificates, and we can apply non-destructive testing (ultrasonic, eddy-current) or hydrostatic pressure tests as specified.

Why choose us?

• We supply alloy steel base tubes suitable for elevated-temperature service (Cr–Mo steels) with high reliability.

• Our fin winding process assures tight fin-to-tube contact and uniform geometry for optimal heat-transfer.

• We offer standard and custom dimensions, fin geometries, and surface-coating options to match air-cooler and heat-exchanger duties.

• We support full documentation, testing, and customization to align with your project specification and quality plan.

Chemical Composition

Mechanical Properties

Applicable Standards

• ASTM / ASME: ASTM A213 / ASME SA213

• EN: EN 10216-2

• JIS: JIS G3462

• GB: GB/T 5310

• Industry compliance: API 661 for air-cooled heat exchangers

Application Areas

General Application Field

These L-foot spiral-wound finned tubes are primarily used in air-cooled and gas-to-liquid heat-exchangers, where one fluid flows inside the tube and air or gas flows over the fins on the outside to extract or reject heat.

Specific Usage Examples

• Air-cooled heat-exchanger bundles in petrochemical plants

• Charge-air coolers or intercoolers in gas-compression systems

• After-coolers for gas-turbine or mechanical-drive units

• Condensers and evaporators with air-side limitations

• Heat-recovery economisers handling flue-gas

• Outdoor air-cooled units in power-plant auxiliary systems

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.