KL Type Finned Tubes for Air-Cooled Heat Exchangers – ASME SA179 Carbon Steel Tubes
Product Overview
KL Type Finned Tubes manufactured with ASME SA179 material are widely used heat transfer components designed for air-cooled heat exchangers (ACHE), industrial coolers, condensers, and process heat exchange equipment. The product combines a seamless cold-drawn low-carbon steel ASME SA179 base tube with an aluminum L-foot fin that is mechanically locked onto a specially knurled tube surface.
The KL finning process creates a stronger mechanical connection between the tube and fin compared with conventional L-type fin tubes. The knurled tube surface increases contact pressure and improves fin stability, making KL finned tubes suitable for applications involving thermal cycling, vibration, and continuous outdoor operation.
ASME SA179 KL finned tubes are commonly selected for refineries, petrochemical plants, natural gas facilities, power generation systems, HVAC equipment, and industrial cooling units where efficient air-side heat transfer and reliable long-term performance are required.
Key Features and Benefits
Enhanced Mechanical Fin Bonding
The KL fin design utilizes:
- Precision knurling on the tube surface
- Helically wrapped L-shaped aluminum fin strip
- Mechanical locking between fin foot and tube
This structure provides improved resistance against fin loosening caused by temperature fluctuations and equipment vibration.
High Heat Transfer Efficiency
The extended fin surface increases the external heat transfer area, allowing air-cooled heat exchangers to achieve higher thermal performance with reduced equipment footprint.
Excellent Formability of ASME SA179 Tube
ASME SA179 low-carbon steel tubes offer:
- Excellent ductility for finning operations
- Uniform wall thickness
- Reliable mechanical strength
- Good thermal conductivity
- Stable performance in heat exchanger service
Cost-Effective Heat Transfer Solution
KL finned tubes provide a balance between performance and economy, making them one of the preferred fin tube designs for medium-temperature air-cooled applications.
Main Applications
ASME SA179 KL finned tubes are widely used in:
Air-Cooled Heat Exchangers (ACHE)
- Refinery air coolers
- Petrochemical process coolers
- Gas compressors after-coolers
- Natural gas cooling systems
- Chemical process cooling units
Condensers and Heat Exchangers
- Hydrocarbon condensers
- Steam condensers
- Oil coolers
- Lubricating oil heat exchangers
- Shell-and-tube heat exchanger bundles
Industrial Cooling Systems
- Power plant auxiliary cooling
- HVAC condenser units
- Refrigeration systems
- Waste heat recovery equipment
Common Specifications and Size Range
| Item |
Typical Specification |
| Base Tube Material |
ASME SA179 Seamless Cold-Drawn Low Carbon Steel |
| Fin Type |
KL Type (Knurled L-Foot Wrapped Fin) |
| Fin Material |
Aluminum 1060 / Aluminum 1100 / Copper (optional) |
| Tube Outside Diameter |
12.7 mm – 38.1 mm (1/2" – 1-1/2") |
| Tube Wall Thickness |
1.0 mm – 3.5 mm |
| Tube Length |
3,000 mm – 18,000 mm |
| Fin Height |
8 mm – 19 mm |
| Fin Thickness |
0.25 mm – 0.50 mm |
| Fin Pitch |
1.5 mm – 3.5 mm (approximately 7–17 fins/inch) |
| Maximum Service Temperature |
Typically up to 250°C depending on fin material and operating conditions |
Customized KL fin tube dimensions can be produced according to customer drawings, thermal design requirements, and heat exchanger manufacturer specifications.
ASME SA179 Chemical Composition
ASME SA179 specifies seamless cold-drawn low-carbon steel tubes for tubular heat exchangers, condensers, and similar heat transfer equipment.
Typical chemical composition:
| Element |
Requirement |
| Carbon (C) |
0.06 – 0.18% |
| Manganese (Mn) |
0.27 – 0.63% |
| Phosphorus (P) |
≤0.035% |
| Sulfur (S) |
≤0.035% |
The controlled low-carbon composition provides excellent machinability, cold working performance, and resistance to cracking during the KL finning process.
ASME SA179 Mechanical Properties
Typical mechanical requirements:
| Property |
Minimum Requirement |
| Tensile Strength |
325 MPa |
| Yield Strength |
180 MPa |
| Elongation |
35% |
| Hardness |
Maximum 72 HRB |
These mechanical properties ensure that the tube can withstand manufacturing processes and maintain structural reliability during heat exchanger operation.
Manufacturing Process
1. Raw Tube Inspection
ASME SA179 seamless tubes are inspected for:
- Chemical composition
- Outer diameter accuracy
- Wall thickness
- Surface condition
- Straightness
2. Tube Knurling
The external tube surface is mechanically processed with a knurled pattern to increase the bonding area between tube and fin.
3. Fin Winding
An aluminum L-shaped fin strip is continuously wrapped around the knurled tube, forming a tight mechanical connection.
4. Fin Compression and Calibration
The fin foot is pressed firmly against the tube surface to improve contact quality and heat transfer efficiency.
5. Final Quality Inspection
Finished KL finned tubes are checked for dimensional accuracy, fin attachment quality, and surface condition.
Inspection and Testing Methods
To ensure compliance with ASME SA179 requirements and customer specifications, KL finned tubes undergo comprehensive inspection:
Base Tube Testing
- Chemical composition analysis by optical emission spectrometer
- Tensile strength testing
- Yield strength testing
- Elongation testing
- Hardness testing
- Flattening test
- Flaring test
- Hydrostatic pressure test
- Eddy current examination
- Ultrasonic testing (when specified)
Finished KL Finned Tube Inspection
- Tube diameter measurement
- Tube length verification
- Fin height inspection
- Fin pitch measurement
- Fin thickness inspection
- Fin bonding examination
- Straightness checking
- Visual surface inspection
Quality Documents
Available documentation includes:
- ASME SA179 material certificates
- EN 10204 3.1 inspection certificates
- Mechanical test reports
- Non-destructive testing reports
- Dimensional inspection records
Industries Served
| Industry |
Typical Equipment |
| Oil & Gas |
Air coolers, process condensers |
| Petrochemical |
Gas coolers, hydrocarbon exchangers |
| Chemical Processing |
Heat recovery systems |
| Power Generation |
Cooling equipment |
| HVAC & Refrigeration |
Condensing units |
| Industrial Manufacturing |
Process cooling systems |
Why Select ASME SA179 KL Finned Tubes?
ASME SA179 KL finned tubes provide a reliable solution for air-cooled heat exchanger applications requiring efficient heat transfer, secure fin attachment, and economical operation. The combination of a high-quality seamless carbon steel tube and mechanically locked aluminum fins delivers stable performance in demanding industrial environments.
With excellent manufacturability, proven heat transfer capability, and broad application flexibility, KL finned tubes remain a preferred choice for engineers designing air coolers, condensers, and industrial heat exchanger systems.
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