L Type Fin Tube (L-Finned Tube) Manufacturer & Exporter
L Type Fin Tubes, commonly called L finned tubes, are tension wound heat transfer components built for low- to medium temperature air cooled heat exchangers, radiators, and HVAC equipment. An aluminum or copper fin strip is mechanically formed into an L shape under precise tension and spirally wrapped tightly around the outer wall of the base tube. The broad horizontal foot of the L profile overlaps continuously with the adjoining fin foot, completely covering the base tube's outer surface and giving it atmospheric corrosion protection alongside a much larger thermal surface area. Amardeep Steel manufactures precision-engineered L-type fin tubes in a wide spectrum of material combinations, offering durable thermal performance and exact dimensional consistency for industrial applications worldwide.
Technical Data
L Fin Tube Technical Specifications
| Component | Standard Specifications / Material Grades |
|---|---|
Base Tube Materials |
• Carbon Steel: ASTM A179 / ASME SA179, ASTM A106 Grade B, ASTM A210 Grade A1 • Stainless Steel: ASTM A249 / A269 TP304/304L, TP316/316L • Copper & Copper Alloys, Duplex & Super Duplex Steel, Titanium |
Fin Strip Materials |
Aluminum (Al 1050, Al 1100, Al 6063), Copper (C11000) |
Manufacturing Standard |
ISO 12244, API 661 (Air-Cooled Heat Exchangers), Manufacturer/Client Drawings |
Chemical Composition of L Shaped Fin Tube Base Materials
| Material Grade | Carbon (C) | Manganese (Mn) | Phosphorus (P) Max | Sulfur (S) Max | Silicon (Si) | Chromium (Cr) | Molybdenum (Mo) | Nickel (Ni) |
|---|---|---|---|---|---|---|---|---|
ASTM A179 |
0.06 to 0.18 |
0.27 to 0.63 |
0.035 |
0.035 |
0.25 max |
|||
ASTM A106 Gr B |
0.30 max |
0.29 to 1.06 |
0.035 |
0.035 |
0.10 min |
0.40 max |
0.15 max |
0.40 max |
SS 304L |
0.030 max |
2.00 max |
0.045 |
0.030 |
0.75 max |
17.5 to 19.5 |
8.0 to 12.0 |
|
SS 316L |
0.030 max |
2.00 max |
0.045 |
0.030 |
0.75 max |
16.0 to 18.0 |
2.00 to 3.00 |
10.0 to 14.0 |
Mechanical Properties of L Shaped Fin Tube Base Materials
| Material Grade | Yield Strength Min (MPa) | Tensile Strength Min (MPa) | Elongation Min (%) | Hardness Max |
|---|---|---|---|---|
ASTM A179 |
180 |
325 |
35 |
72 HRB |
ASTM A106 Gr B |
240 |
415 |
30 |
79 HRB |
SS 304L |
170 |
485 |
40 |
201 HBW |
SS 316L |
170 |
485 |
40 |
217 HBW |
L Fin Tube Standard Dimensional Ranges
Our L type fin tubes are available in standard dimensional ranges covering most air cooler and radiator designs.
| Specification Parameter | Standard Dimensional Range | Metric / Imperial Units |
|---|---|---|
Base Tube Outer Diameter (OD) |
12.7 mm to 38.1 mm |
0.50 inch to 1.50 inch |
Base Tube Wall Thickness |
1.24 mm to 3.5 mm |
0.049 inch to 0.138 inch |
Fin Height |
9.5 mm to 15.8 mm |
0.375 inch to 0.625 inch |
Fin Thickness |
0.33 mm to 0.50 mm |
0.012 inch to 0.020 inch |
Fin Density / Pitch |
7 to 11 fins per inch (FPI) |
275 to 433 fins per meter |
Maximum Tube Length |
Up to 18,000 mm |
Up to 59 ft |
L Type Finned Tube Working Temperature & Pressure Limits
L type fin tubes are designed for low-to-medium temperature operating windows where surface protection is required.
| Parameter / Metric | Operating Limit | Operational Considerations |
|---|---|---|
Maximum Operating Temperature |
150 degrees Celsius |
Above 150 degrees Celsius, differential thermal expansion between the aluminum fin and the steel tube can reduce contact tension |
Base Tube Pressure Rating |
Up to 250 bar (3,625 psi) |
Internal working pressure rating depends on base tube material grade and wall thickness |
Atmospheric Resistance |
High |
The overlapping L foot protects the tube's outer surface from corrosive ambient air |
Vibration Tolerance |
Moderate |
Best suited to steady, moderate velocity forced air streams |
Comparison: L-Type vs. LL-Type vs. Embedded (G-Type) Fin Tubes
| Feature / Metric | L Type Fin Tube | Double L (LL) Fin Tube | Embedded (G-Type) Fin Tube |
|---|---|---|---|
Fin Base Geometry |
Single L-shaped foot overlap |
Double overlapping L-foot |
Machined groove inside tube wall |
Max Working Temp |
150 degrees Celsius |
180 degrees Celsius |
400 degrees Celsius |
Corrosion Protection |
Good (Complete tube coverage) |
Excellent (Double lap seal) |
Moderate (Exposed base tube) |
Mechanical Bond Strength |
Tension-bound |
High tension-bound |
Mechanical groove lock |
Cost Profile |
Economical & cost-effective |
Moderate |
Higher machining cost |
Key Industrial Applications of L Type Finned Tube
- Air Cooled Heat Exchangers (ACHE): Used in oil refineries, gas processing plants, and chemical manufacturing for cooling ambient process fluids.
- Radiators & Air Coolers: Industrial machinery cooling units, engine radiators, and generator set cooling systems.
- HVAC & Refrigeration Systems: Large-scale commercial air conditioning condensers and air-chilling evaporators.
- Compressor Gas Cooling: Intercoolers and aftercoolers in gas compressor stations, paired with rugged boiler pipes and headers.
Frequently Asked Questions: L Type Fin Tubes
1. What is the main difference between an L Type Fin Tube and a KL Fin Tube?
L Type relies purely on mechanical tension over a smooth tube, whereas KL Fin Tubes knurl micro-grooves into the base pipe before wrapping to create a mechanical interlock.
2. What are the maximum operating temperatures for L Type Fin Tubes?
L Type Fin Tubes handle operating temperatures up to 150 degrees Celsius. Beyond this limit, thermal expansion differences can loosen fin contact.
3. How do L-shaped fin feet protect the base tube from atmospheric corrosion?
The horizontal leg of each L-fin overlaps the foot of the adjacent fin, creating a continuous metal barrier that seals the base tube against moisture and air.
4. Which fin and base tube materials are most commonly paired together?
High-conductivity aluminum or copper fins are wrapped around carbon steel ASTM A179, stainless steel TP316L, or alloy tubes.
5. Can L Type fin tubes be cleaned using high-pressure water washing?
Yes, but sprays must be directed parallel to fins under controlled pressure to prevent bending the thin aluminum or loosening the tension bond.
6. When should I select L Type fins over Embedded (G-Type) or Extruded Fin Tubes?
Choose L Type fins for lightweight, budget-sensitive air cooling systems under 150 degrees Celsius that require full outer tube corrosion protection without grooving the pipe wall.
7. How are the bare ends of L Type Fin Tubes prepared for tube sheet integration?
Fin wrapping stops short of the tube ends per client drawings. The fin ends are mechanically clamped or metal-sprayed to prevent unravelling, leaving clean bare pipe for welding into header sheets or attaching ASME ANSI B16.5 weld neck flanges.
8. Can L Type Fin Tubes withstand cyclic thermal shocks without losing thermal contact?
While they perform reliably within continuous 150 degrees Celsius limits, frequent, extreme thermal cycling can gradually reduce tension grip over time. For high-shock services, KL or embedded fins are recommended.
9. How do you calculate total heat transfer area for an L Type Fin Tube bundle?
The total heat transfer area combines the external surface area of all vertical fin legs plus the exposed bare tube ends, providing up to 8 to 12 times the primary surface area of a smooth tube.
Request a Technical Quote & Custom Size Estimate
Looking for high-efficiency L-type fin tubes for your heat exchanger build or bundle replacement project? For a wider look at our tube range, see our finned tubes hub page and heat exchanger tubes product line or send an enquiry directly for a quote on L Type Fin Tube built to your specification.
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