ASME SA179 KL Type Aluminum Finned Tube for Economizer and Heat Recovery
KL Type Wound Finned Tube – ASTM A179 Carbon Steel Base Tube with Aluminum Fins
Product Introduction
KL Type Wound Finned Tubes (also known as Knurled L-Foot Tension Wound Finned Tubes) are high-efficiency heat transfer components designed for air-cooled heat exchangers, economizers, and industrial cooling systems.
This product features a seamless cold-drawn ASTM A179 / ASME SA179 carbon steel base tube combined with high-purity aluminum (AL1060 / AL1100) fins. The unique knurled L-foot tension-winding process creates a strong mechanical interlock between the fin foot and the base tube surface, delivering superior heat transfer performance, improved vibration resistance, and reliable operation up to 250–260°C.
Finned Tube Structure – ASTM A179 Base Tube + Aluminum Fins
1. Base Tube Material: ASTM A179 / ASME SA179 Carbon Steel
Seamless cold-drawn low-carbon steel tube manufactured to ASTM A179 / ASME SA179 standards. The outer surface is precisely knurled before finning to enhance mechanical bonding.
2. Fin Material: Aluminum (AL1060 / AL1100)
High-purity aluminum strip is formed into an L-shape and tension-wound onto the knurled base tube. After winding, the L-foot is further knurled into the tube surface, locking the fin securely in place.
3. Embedding / Manufacturing Process
- Base tube outer surface is knurled
- Aluminum strip is continuously formed into L-profile and tightly wound under controlled tension
- Fin foot is simultaneously knurled into the tube surface
- Both ends of the tube are left bare (unfinned) for welding or tube-sheet insertion
- Tubes are cleaned, dried, and anti-rust protected at ends
This process increases metal-to-metal contact area by approximately 30–50% compared with standard L-type fins, resulting in lower thermal resistance and better long-term performance under thermal cycling.
Chemical Composition – ASTM A179 Base Tube Material
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.06 – 0.18 |
| Manganese (Mn) | 0.27 – 0.63 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
Mechanical Properties of ASTM A179 Base Tube
| Property | Value |
|---|---|
| Tensile Strength | ≥ 325 MPa |
| Yield Strength | ≥ 180 MPa |
| Elongation | ≥ 35% |
| Hardness | ≤ 72 HRB |
Chemical Composition – Aluminum Fin Material (AL1060)
| Element | Content (%) |
|---|---|
| Aluminum (Al) | ≥ 99.6 |
| Silicon (Si) | ≤ 0.25 |
| Iron (Fe) | ≤ 0.35 |
| Copper (Cu) | ≤ 0.05 |
| Manganese (Mn) | ≤ 0.03 |
| Zinc (Zn) | ≤ 0.05 |
| Others (each) | ≤ 0.03 |
| Others (total) | ≤ 0.10 |
Dimensional Range & Tolerance – ASTM A179 + Aluminum KL Finned Tube
| Parameter | Standard Range | Typical Tolerance |
|---|---|---|
| Base Tube Outside Diameter (OD) | 15.88 – 50.8 mm (5/8" – 2") | ±0.1 mm |
| Base Tube Wall Thickness | 1.0 – 3.0 mm (min. 1.65 mm recommended) | As per ASTM A179 |
| Fin Height | 6.35 – 25.4 mm (common 10 – 16 mm) | ±0.5 mm |
| Fin Thickness | 0.3 – 0.5 mm (typical 0.4 mm) | ±0.03 mm |
| Fin Pitch / FPI | 2.1 – 6.0 mm / 7 – 11 FPI | ±0.2 mm per 100 mm |
| Tube Length | Up to 18,000 mm | Customized |
| Unfinned Ends | As required (usually 50 – 150 mm each end) | — |
Performance Advantages
- Excellent heat transfer efficiency due to increased contact area from knurled L-foot design
- Maximum continuous operating temperature: 250–260°C
- Maximum working pressure: up to 3.2 MPa
- Good atmospheric corrosion resistance (fin foot protects base tube)
- High resistance to vibration and thermal cycling
- Lightweight aluminum fins reduce overall equipment weight
- Cost-effective alternative to extruded or G-type finned tubes for medium-temperature applications
- Fully mechanical bonding – no welding or brazing required
Application Fields
KL Type ASTM A179 + Aluminum Finned Tubes are widely used in:
- Air-cooled heat exchangers (ACHE) in petrochemical and oil & gas plants
- Economizers and air heaters in power generation and waste-heat recovery systems
- Compressor coolers and gas coolers
- HVAC and industrial dry coolers
- Refrigeration and air-conditioning systems
- Chemical and fertilizer plant process coolers
- Incineration and flue-gas heat recovery units
Our Advantages & Experience
As a specialized manufacturer and exporter of finned tubes, we offer:
- Full production capability for L, LL, KL, G, and extruded finned tubes
- Strict quality control according to ASTM, ASME, and customer specifications
- Mill Test Certificates (EN 10204 3.1 / 3.2) provided with every shipment
- Custom sizes, bare ends, and packaging available
- Extensive export experience to Europe, Middle East, Southeast Asia, and South America
- Competitive pricing with reliable lead times and professional technical support
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.