L-Footed Fin Tubing (Carbon Steel) for Industrial Radiators

Material Overview

This product is a helical finned tube featuring an “L-foot” style fin (also called L-type/wrap-on fin) wound around a carbon steel base tube. The fin foot forms an L-shaped contact on the tube surface, providing robust mechanical contact between fin and tube and hence enhanced heat transfer and corrosion resistance.
It is used as a heat‐exchange element in industrial radiators, air coolers, condensers, waste heat recovery units, etc., where a fluid (liquid or gas) inside the tube transfers heat to air or another external medium via the finned outer surface.

Specifications

Typical specification ranges (for L-foot / L-type fin tubes) are as follows:

• Tube outside diameter (OD): ~ 19 mm to ~ 51 mm (≈ ¾″ to 2″)

• Wall thickness of base tube: depends on OD but for carbon steel heat exchanger tube, e.g. ASTM A179 seamless cold-drawn, typical minimum wall ~2.4 mm for 25.4 mm OD.

• Fin height: typically 10 mm to 16 mm (≈0.4″ to 0.63″)

• Fin thickness: typically ~0.3 mm to ~0.5 mm (≈0.012″ to 0.02″)

• Fin pitch (spacing): e.g., 3 FPI to 11 FPI (fins per inch) ≈ 100 to 433 fins per meter.

• Tube length: up to 22 000 mm (≈72 ft) in some manufacturers.

• Typical base tube carbon steel grades: SA179, SA192, SA210A1/C, SA106Gr.B.

Major Features

• High heat‐transfer efficiency: The L-foot fin significantly increases outer surface area and creates a strong bond with the base tube, enhancing conduction from tube to fin and convection from fin to outside medium.

• Compact design: Because the fin increases surface area, fewer tubes (or smaller radiator volume) can achieve required heat duty compared to bare tubes.

• Enhanced bonding & durability: The “L” foot provides stronger mechanical attachment of fin to tube than simple welded or wrapped fins, better resisting fin loosening under thermal cycling or vibration.

• Good corrosion/erosion resistance on outer fin foot: The fin foot wraps securely around the base tube and helps protect the tube from outer‐side attack in some installations.

• Flexibility for industrial radiator applications: Suitable for fluids such as hot water, steam, thermal oil, and gases cooled by ambient air, fans, or ducts.

Our Advantages

Here are key customer concerns and how our offering addresses them:

• Concern: Heat transfer performance / surface area
  Advantage: Our L-foot finned tubes maximize the fin-foot contact area and ensure consistent fin geometry (height, thickness, pitch) which translates to higher outer surface area per unit length and stronger conduction to the fin. This yields measurable efficiency improvements compared to standard wrapped fins.

• Concern: Long‐term fin integrity under thermal cycling / vibration
  Advantage: The mechanical interlock of the L-foot design resists fin loosening and fatigue better. Our manufacturing uses tight process control to maintain fin bond strength and alignment, reducing maintenance and downtime.

• Concern: Corrosion / coating / environment aggressiveness
  Advantage: We offer carbon steel base tube with L-foot fins of options (aluminum, or carbon steel fin material) and can also provide protective coatings or surface treatments. The L-foot design assists in protecting the tube outer surface. For more aggressive environments we can recommend LL-type, KL-type or other advanced fin types.

• Concern: Custom geometry and radiator integration (tube length, fin height, spacing)
  Advantage: We support flexible customization of diameter, wall thickness, fin height/pitch, plain ends, U-bends, lengths up to ~22 m, based on your radiator layout or exchanger module design.

• Concern: Standards & quality assurance
  Advantage: Our base tube material meets known standards (e.g., ASTM A179) with documented chemical and mechanical properties, and the finning process is traceable. We provide material certificates, test reports (flattening, flaring, hydrostatic, hardness) as required under the relevant standards.

Chemical Composition

* Exact composition ranges vary with sub-grades.

Mechanical Properties

Applicable Standards

• ASTM A179 / ASME SA179 — Seamless cold-drawn low-carbon steel tubes for tubular heat-exchangers and condensers.

• EN 10216-1 / EN 10216-2 — Seamless steel tubes for pressure purposes.

• GB/T 3087 — Seamless steel tubes for heat-exchangers.

• Additional manufacturing and NDT standards depending on customer requirements (flattening, flaring, hydrostatic, eddy-current, visual inspection).

Application Areas

Overview

This type of carbon steel L-foot finned tubing is suitable for a variety of industrial radiator and heat-exchange applications where one side is a process fluid (hot liquid, steam, thermal oil) and the other side is ambient or forced air.

Specific Uses

• Industrial radiators for hot water/steam heating.

• Air coolers and after-coolers in petrochemical and refinery installations.

• Waste heat recovery units such as economisers and air pre-heaters.

• HVAC and large-building heating/cooling systems.

• Process drying and hot-air systems in textile, printing, chemical and food industries.