KL Fin Tubes Manufacturer & Supplier in India
KL Fin Tubes, also known as knurled L Fin Tubes, are tension-wound fin tubes designed for applications requiring greater fin-to-tube stability than standard L Fin Tubes. The fins are positioned closely together, helping reduce exposure of the tube surface and providing improved protection against corrosion. KL Fin Tubes typically operate in the 250-degree Celsius to 320-degree Celsius range, making them suitable for applications where conventional L Fin Tubes may not provide sufficient performance. They offer an intermediate solution between standard wound fins and fully embedded or extruded fin tubes. Amardeep Steel Centre manufactures and exports KL Fin Tubes in stainless steel and other specialty tube materials for industrial heat transfer applications.
What Are KL Fin Tubes?
A KL Fin Tube is a modified L Fin Tube in which the fin foot is mechanically secured to a knurled tube surface. During manufacturing, the outer surface of the base tube is first treated with a rotating knurling tool to create a pattern of small grooves.
An L-shaped fin strip is then helically wound around the tube under controlled tension. The horizontal foot of the fin is pressed into the knurled surface, creating a mechanical interlock between the fin and the tube. This construction provides a more secure fin attachment and improved heat-transfer performance compared with a conventional surface-wound L-fin tube.
Technical Data
Specifications of KL Fin Tubes
| Parameter | Specification |
|---|---|
Fin Type | KL, Knurled L type, tension wound |
Fin Material | Aluminium, Copper |
Base Tube Material | Carbon Steel, Stainless Steel TP304, Stainless Steel TP316, Copper, Alloy Steel |
Fin Height | 6.35 mm to 25.40 mm |
Fin Thickness | 0.4 mm to 0.5 mm |
Fins Per Inch (FPI) | 7 to 11 FPI, alternate density available on request |
Tube Outer Diameter | 15.88 mm to 50.80 mm |
Minimum Tube Wall Thickness | 1.83 mm |
Tube Length | Up to 18 metres |
Documentation | Mill Test Certificate supplied with every order |
Mechanical Strength Properties of KL Fin Tube Base Materials
| Grade | Tensile Strength (Min) | Yield Strength (Min) | Elongation (Min) | Hardness (Max) |
|---|---|---|---|---|
Carbon Steel A106 Gr B | 415 MPa | 240 MPa | 30% | 137 HBW |
Stainless Steel TP304 (A213) | 515 MPa | 205 MPa | 35% | 92 HRB |
Stainless Steel TP316 (A213) | 515 MPa | 205 MPa | 35% | 95 HRB |
Copper C12200 | 220 MPa | 69 MPa | 35% | 40 HRB |
The chromium and nickel in TP304 and TP316 base tubes carry the corrosion resistance that a KL Fin Tube needs when it is running in flue gas or process water service, and the added molybdenum in TP316 is worth specifying wherever chlorides are in the stream. Carbon steel A106 Gr B stays the more economical base tube for clean, non-corrosive air-side duty.
Mechanical Properties of KL Finned Tubes
| Property | Copper | Aluminium | Steel | Stainless Steel | Brass |
|---|---|---|---|---|---|
Density (g/cm³) | 8.96 | 2.7 | 7.85 | 8.0 | 8.5 |
Thermal Conductivity (W/m·K) | 390 | 205 | 50 | 16 | 109 |
Young's Modulus (GPa) | 110–130 | 69 | 200 | 190–210 | 100 |
Yield Strength (MPa) | 70–200 | 90–140 | 250–350 | 190–350 | 200 |
Ultimate Tensile Strength (MPa) | 220–260 | 200–300 | 400–550 | 515–750 | 300–500 |
Corrosion Resistance | Excellent | Good | Poor (if uncoated) | Excellent | Good |
Specific Heat (J/g·K) | 0.385 | 0.897 | 0.49 | 0.50 | 0.377 |
Dimension Chart for KL-Type Fin Tubes
| Bare Tube OD | Fin Height | Fin Thickness | FPI |
|---|---|---|---|
15.88 mm to 19.05 mm | 6.35 mm to 12.70 mm | 0.4 mm | 7 to 9 FPI |
25.40 mm to 31.75 mm | 12.70 mm to 19.05 mm | 0.4 mm to 0.5 mm | 8 to 10 FPI |
38.10 mm to 50.80 mm | 19.05 mm to 25.40 mm | 0.5 mm | 9 to 11 FPI |
Match your bare tube diameter against this chart to get the right fin height and density for your tube sheet or heat exchanger layout. If your project falls outside these ranges, share your drawing with our team, and we will confirm what can be produced.
Working Pressure and Operating Temperature of KL Fin Tubing
| Parameter | Typical Rating |
|---|---|
Maximum Operating Temperature | 250 deg C to 320 deg C, depending on fin material and bond condition |
Maximum Working Pressure | Up to 3.2 MPa, approximately 32 bar, on the process side |
The exact figure for your order depends on the base tube material, wall thickness, and the design code your heat exchanger is built to. Send us your process conditions, and we will confirm the working pressure and temperature rating for your specific KL Fin Tube order before you finalise the design.
How KL Fin Tubes Differ from L and LL Fin Tubes
| Feature | L Fin Tube | LL Fin Tube | KL Type Fin Tube |
|---|---|---|---|
Fin Attachment | Fin is held in place by tension around the smooth base tube. | Fin foot overlaps for additional grip and protection | Fin foot is mechanically locked into the knurled surface of the base tube |
Base Tube | Smooth | Smooth | Knurled before fin winding |
Mechanical Grip | Moderate | Better than L type | Strongest of the three |
Corrosion Protection | Basic | Improved due to overlapping fin foot | Good mechanical attachment and improved protection |
Approx. Working Temperature | Up to 150°C | Up to 170°C | Approximately 250°C–320°C |
Cost | Most economical | Moderate | Higher than L and LL types |
Best Suited For | Lower-temperature applications where cost is important | Applications requiring additional grip and corrosion protection | Higher-temperature applications requiring stronger fin attachment |
Main Advantage | Low cost and simple construction | Better protection and mechanical grip than L type | Superior fin-to-tube attachment and higher temperature capability |
Tube Selection Guide
| Application Requirement | Recommended Type |
|---|---|
Lower temperature + lowest cost | L Fin Tube |
Moderate temperature + additional corrosion protection | LL Fin Tube |
Higher temperature + strong mechanical fin attachment | KL Fin Tube |
Applications of KL-Type Finned Tubes
- Chemical and petrochemical processing
- Power generation and thermal power stations
- Paper and pulp drying systems
- Food and beverage spray drying, including plant protein and starch processing
- Building and space heating systems
- Air coolers and industrial heat exchanger tubes assemblies
KL Fin Tubes are also specified in condenser tubes bundles where the process side runs hotter than a standard L fin can hold up to over the life of the exchanger.
Available Materials
KL Fin Tubes from Amardeep Steel Centre are available in the following base tube materials, matched to your process fluid and temperature:
- Stainless Steel Finned Tubes
- Carbon Steel Finned Tubes
- Alloy Steel Finned Tubes
- Copper Finned Tubes
- Aluminium Finned Tubes
- Brass Finned Tubes
Frequently Asked Questions
What are KL Fin Tubes?
KL Finned Tubes, also known as Knurled L Fin Tubes, are wound fin tubes where the base tube is knurled before the L shaped fin foot is wrapped around it and rolled into the grooves, giving a stronger mechanical bond than a plain L fin.
What does the K in KL Fin Tube stand for?
The K stands for knurled, referring to the knurling pattern cut into the base tube before the fin is wound on.
How is a KL Fin Tube different from an L Fin Tube or LL Fin Tube?
An L Fin Tube holds the fin in place with tension against a smooth tube, rated up to around 150 degrees Celsius. An LL Fin Tube overlaps the fin foot for added grip and corrosion resistance, rated up to around 170 degrees Celsius. A KL Fin Tube knurls the base tube first so the fin foot locks mechanically into the surface, taking the operating range up to 250 degrees Celsius to 320 degrees Celsius.
What is the maximum operating temperature and pressure for KL Fin Tubes?
KL Fin Tubes are typically rated for 250 degrees Celsius to 320 degrees Celsius and up to 3.2 MPa, roughly 32 bar, on the process side. Exact ratings depend on base tube material, wall thickness and the design code the heat exchanger is built to, so confirm with our team for project-specific figures.
Which materials are KL Fin Tubes available in?
Amardeep Steel Centre supplies KL Fin Tubes with Carbon Steel, Stainless Steel TP304 and TP316, Copper and Alloy Steel base tubes, with Aluminium or Copper fins.
What industries use KL Fin Tubes?
KL Fin Tubes are widely used in chemical and petrochemical processing, power generation, paper and pulp drying, food and beverage spray drying, building heating systems, and industrial air coolers.
Does Amardeep provide Mill Test Certificates with KL Fin Tubes?
Yes, every order of KL Fin Tubes ships with a mill test certificate covering the chemical and mechanical properties of the base tube and fin material used.
Related Fin Tube Types
Helical serrated finned tubes, finned tubes, crimped finned tubes, shoulder tension finned tubes, G fin tubes, H fin tubes, helical solid finned tubes and helically wound high fin tubes.
Request a quote for KL finned tubes
Match your bare tube diameter against this chart to get the right fin height and density for your tube sheet or heat exchanger layout. If your project falls outside these ranges, Request a quote from our team and we will confirm what can be produced.
