I-type longitudinal fin tubes are heat transfer tubes fitted with straight fins running parallel to the tube axis. The fin strip is attached directly to the outer surface of the base tube, normally by resistance welding along the tube length. This construction increases the external heat transfer area while maintaining a simple and practical fin arrangement.
The straight fin design is suitable for applications where longitudinal heat transfer surfaces are required without the additional forming of a folded channel. I-type longitudinal fin tubes are commonly considered for double pipe heat exchangers, multi-pipe heat exchangers, fired heaters, gas coolers, gas heaters, and tank heating systems.
Amardeep Steel Centre supplies I-type longitudinal fin tubes with attention to fin geometry, weld attachment, dimensional consistency, and material documentation. Each requirement can be reviewed against the intended heat transfer application before production and dispatch.
Technical Data
Specifications of I-Type Longitudinal Fin Tubes
| Parameter | Specification |
|---|---|
|
Fin Type |
I-Type longitudinal, resistance welded, single straight strip |
|
Base Tube Materials |
Carbon steel A106, A179, A192 and A210; stainless steel TP304, TP316, TP321 and TP310S |
|
Fin Materials |
Carbon steel or stainless steel, matched to the base tube |
|
Fin Arrangement |
Longitudinal fins running parallel to the tube axis |
|
Number of Fins |
2 to 24 fins per tube, confirmed against thermal design |
|
Base Tube Outer Diameter |
25 mm to 219 mm |
|
Fin Height |
12 mm to 50 mm |
|
Fin Thickness |
2 mm to 4 mm |
|
Tube Orientation |
Horizontal or vertical service |
|
Tube Length |
Cut length per project drawing |
|
Documentation |
Mill Test Certificate and inspection documents as specified |
Longitudinal I-Type Finned Tubes Chemical Composition
The chemical composition depends on the selected base tube grade. The following values represent commonly specified grades and should be confirmed against the applicable material standard and Mill Test Certificate for each order.
| Grade | Carbon C | Manganese Mn | Chromium Cr | Nickel Ni | Molybdenum Mo |
|---|---|---|---|---|---|
|
ASTM A179 |
0.06% to 0.18% |
0.27% to 0.63% |
Not specified |
Not specified |
Not specified |
|
ASTM A106 Grade B |
0.30% max |
0.29% to 1.06% |
0.40% max |
0.40% max |
0.15% max |
|
ASTM TP304 |
0.08% max |
2.00% max |
18.00% to 20.00% |
8.00% to 10.50% |
Not specified |
|
ASTM TP316 |
0.08% max |
2.00% max |
16.00% to 18.00% |
10.00% to 14.00% |
2.00% to 3.00% |
Mechanical Properties of I-Type Longitudinal Finned Tubes
Mechanical properties are governed by the base tube material and applicable product standard. Typical minimum values for commonly specified grades are shown below.
| Grade | Tensile Strength Minimum | Yield Strength Minimum | Elongation Minimum |
|---|---|---|---|
|
ASTM A179 |
325 MPa |
180 MPa |
35% |
|
ASTM A106 Grade B |
415 MPa |
240 MPa |
30% |
|
ASTM TP304 |
515 MPa |
205 MPa |
35% |
|
ASTM TP316 |
515 MPa |
205 MPa |
35% |
I-Type Longitudinal Fin Tube Dimension Chart
| Base Tube OD | Fin Height | Fin Thickness |
|---|---|---|
|
25 mm to 50 mm |
12 mm to 20 mm |
2 mm to 3 mm |
|
50 mm to 114 mm |
20 mm to 35 mm |
3 mm to 4 mm |
|
114 mm to 219 mm |
35 mm to 50 mm |
3 mm to 4 mm |
Applications of I-Type Longitudinal Fin Tubes
I-type longitudinal fin tubes are selected where straight longitudinal heat transfer surfaces are useful for the equipment design.
- Double Pipe Heat Exchangers: The straight fin arrangement is suitable for tube-in-tube heat exchanger construction.
- Multi-Pipe Heat Exchangers: Used where several finned tubes are installed within a larger heat transfer assembly.
- Fired Heaters: Longitudinal fin tubes can increase external heat transfer area in selected heater designs.
- Gas Coolers and Heaters: Suitable for equipment requiring greater external surface area for gas-side heat transfer.
- Tank Heaters: Used for heating process fluids where longitudinal fin surfaces suit the equipment arrangement.
- Chemical and Petrochemical Plants: Applied in process heat transfer equipment subject to project-specific material requirements.
- Oil and Power Equipment: Used in selected heat exchangers and thermal systems.
Frequently Asked Questions
What is an I-Type Longitudinal Fin Tube?
An I-Type Longitudinal Fin Tube has a straight fin strip welded directly to the base tube and running parallel to the tube axis.
How does an I-type longitudinal fin tube differ from an L-type or U/T-type tube?
I-Type uses a single straight strip. L-type adds an angled foot for wider weld contact. U-type and T-type constructions fold the strip into a channel that produces a pair of opposing fins from one weld pass, giving a higher fin count at a higher cost. See the comparison table above for the full breakdown.
Why choose longitudinal fins for a double pipe heat exchanger?
Longitudinal fins suit tube-in-tube arrangements because they run along the tube length and fit naturally inside the annular space between two tubes, providing an additional heat transfer area while maintaining a continuous flow channel.
What is the maximum operating temperature for I-Type longitudinal fin tubes?
Carbon steel base tubes are typically rated up to 450 degrees Celsius, and stainless steel base tubes up to 600 degrees Celsius. The exact figure depends on wall thickness, working pressure, and the design code your equipment is built to, so confirm project-specific ratings with our team.
Which materials are available for I-type longitudinal fin tubes?
Common options include carbon steel (A106, A179, A192, A210) and stainless steel (TP304, TP316, TP321, TP310S), with the combination selected according to temperature, corrosion conditions, and thermal requirements.
Does Amardeep provide Mill Test Certificates with I-Type Longitudinal Fin Tubes?
Yes, every order ships with a mill test certificate and inspection documentation covering the chemical and mechanical properties of the material used.
Request a Quote for I-Type Longitudinal Fin Tubes.
Share your tube grade, tube OD, wall thickness, tube length, fin height, fin thickness, fin count, operating temperature, working pressure, and quantity for a project-specific quotation.
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