L Type Spiral Wound Finned Tube (ASTM A179 + Aluminum Fins) for Air Cooled Heat Exchangers

High-Efficiency L-Foot Tension Wound Finned Tubes – ASTM A179 Carbon Steel Base with Aluminum Fins

Our L-type (L-footed / tension wound) finned tubes combine a robust ASTM A179 seamless carbon steel base tube with high-conductivity aluminum fins. This design delivers excellent heat transfer performance in air-cooled and gas-flow applications while providing cost-effective corrosion protection to the base tube.

As a specialized manufacturer and exporter of finned heat exchanger components, we produce premium L-type finned tubes that meet international standards. These tubes are ideal for moderate-temperature environments, offering an optimal balance of performance, durability, and economics.

Product Material Specifications

Base Tube Material: ASTM A179 / ASME SA179 Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger Tubes Fin Material: Aluminum (typically AL 1060, 1100, or equivalent)

Chemical Composition

ASTM A179 Base Tube Chemical Composition (wt.%):

Aluminum Fin Material Chemical Composition (Typical for 1060/1100 Grade): Aluminum ≥ 99.60% (1060) or ≥ 99.00% (1100), with trace elements (Fe, Si, Cu, etc.) tightly controlled for excellent thermal conductivity, formability, and corrosion resistance.

L Type Finned Tube Structure and Manufacturing Process

Our L-type finned tubes use the tension wound / L-footed wrapping process:

• Base Tube: ASTM A179 seamless low-carbon steel tube provides high pressure resistance and excellent weldability for heat exchanger assemblies.
• Fins: Aluminum strip is formed into an L-shape (foot) and helically wound under controlled tension around the base tube. The L-foot creates a broad contact area that protects the tube surface from atmospheric corrosion.
• Winding Process: The aluminum fin strip is spirally wrapped with tension, mechanically locking the fin foot tightly to the tube. This creates a strong mechanical bond without welding or embedding, ensuring good thermal contact while allowing for thermal expansion differences between steel and aluminum.

The L-type design is particularly suitable for operating temperatures up to approximately 150°C (302°F), offering moderate mechanical strength and good atmospheric corrosion resistance.

Dimensions and Tolerances

We offer flexible manufacturing with tight tolerances to meet customer drawings and international standards.

Typical Dimensions (Customizable):

• Base Tube OD: 16 mm – 63 mm (common sizes: 19 mm, 25 mm, 38 mm, 50 mm, etc.)
• Fin Height: 6 mm – 25 mm
• Fin Thickness: 0.3 mm – 0.6 mm
• Fin Density: 8 – 16 Fins Per Inch (FPI) / 3 – 11 fins per 25.4 mm
• Tube Length: Up to 12–18 meters

Dimensional Tolerances (Standard Ranges):

• Base Tube OD: ±0.08 mm to ±0.15 mm
• Wall Thickness: ±10% or per ASTM A179
• Fin Height: ±0.5 mm
• Fin Pitch (Spacing): ±1–2%
• Fin Bond: Tight tension wrap with no gaps

All products undergo strict quality inspection, including dimensional checks, bond integrity testing, and hydrostatic testing where required.

Performance Advantages

• Enhanced Heat Transfer: The spirally wound aluminum fins significantly increase the external surface area (typically 3–8 times that of bare tubes), improving air-side heat transfer efficiency.
• Lightweight & High Conductivity: Aluminum fins provide excellent thermal conductivity while reducing overall weight.
• Corrosion Protection: The L-foot design covers and protects the carbon steel base tube from direct atmospheric exposure.
• Cost-Effective: More economical than extruded or embedded types for moderate temperature applications.
• Good Thermal Contact: Tension winding ensures consistent fin-to-tube contact pressure for reliable performance.
• Flexibility: Suitable for bending and assembly in large air-cooled heat exchanger bundles.

Detailed Application Fields

Our ASTM A179 L-type aluminum finned tubes are widely used in:

• Air-Cooled Heat Exchangers (ACHE): Condensers, coolers, and radiators in refineries and petrochemical plants.
• Power Generation: Air preheaters, steam condensers, and auxiliary cooling systems.
• Petrochemical & Chemical Processing: Process gas coolers, overhead condensers, and heat recovery units.
• HVAC & Refrigeration: Large-scale air handling units, dry coolers, and commercial cooling systems.
• Oil & Gas: Compressor coolers and equipment cooling in upstream and downstream operations.
• Other Industries: Metallurgy, food processing, and general industrial heat recovery where moderate temperatures and air cooling are required.

These tubes perform best in gas-to-liquid heat exchange where the gas side (air) is the controlling resistance.

Why Choose Us? Our Advantages and Expertise

With extensive experience in finned tube manufacturing and global export, we differentiate ourselves through:

• Advanced Production Technology: Precision tension winding machines for consistent fin quality and tight bonding.
• Material Assurance: Sourced ASTM A179 tubes and high-purity aluminum fin stock, with full Material Test Certificates (MTC).
• Customization Capability: Tailor-made dimensions, fin densities, lengths, and configurations according to client specifications.
• Quality Control: ISO-compliant processes, third-party inspection support (SGS, BV, TUV, etc.), and complete traceability.
• Export Expertise: Proven delivery to Europe, Middle East, Southeast Asia, and the Americas. We handle professional export packaging, documentation, and Incoterms.
• Technical Support: Engineering assistance for thermal design, material selection, and system optimization.
• Competitive Value: Direct factory pricing combined with reliable lead times and superior after-sales service.

Contact us today for quotations, technical datasheets, samples, or custom engineering support. Our L-type finned tubes (A179 base + AL fins) provide dependable, high-performance solutions for your air-cooled heat transfer needs.