Rectangular finned tubes are the twin tube configuration of the H fin construction, built by resistance welding fin plates across two base tubes positioned side by side instead of one. The result is an H-shaped cross section repeated across both tubes, giving a wider, more rigid finned section than a single tube can offer on its own. This construction is also known as a Double H Fin Tube or HH type finned tube, three names for the same product used interchangeably across the industry.
Amardeep Steel Centre manufactures the single tube version of this same H-fin construction on ourWelded Square Fin Tubes page. Choose rectangular finned tubes when a tube row needs the extra rigidity a twin tube build provides, particularly on longer runs where a single tube section would flex under its own length.
Technical Data
Specifications of Rectangular Finned Tubes
Parameter | Specification |
|---|---|
Fin Type | Rectangular, twin tube H fin (Double H), resistance welded |
Base Tube Material | Carbon Steel A179, A192, A210; Alloy Steel A213 T5, T11, T22; Stainless Steel TP304, TP316 |
Fin Material | Carbon Steel, Alloy Steel, Stainless Steel, matched to base tube |
Bare Tube Outer Diameter | 25 mm to 65 mm per tube, twin tube configuration |
Fin Size | Approximately 2 times the bare tube diameter on each side |
Fin Thickness | 2 mm to 4 mm |
Fin Spacing | 12.7 mm minimum, confirmed against tube bank drawing |
Documentation | Mill Test Certificate supplied with every order |
Chemical Composition of Rectangular Fin Tube
Grade | Carbon (C) | Manganese (Mn) | Chromium (Cr) | Molybdenum (Mo) |
|---|---|---|---|---|
Carbon Steel A179 | 0.06% to 0.18% | 0.27% to 0.63% | — | — |
Alloy Steel A213 T11 | 0.05% to 0.15% | 0.30% to 0.60% | 1.00% to 1.50% | 0.44% to 0.65% |
Stainless Steel TP304 | 0.08% max | 2.00% max | 18.00% to 20.00% | — |
Stainless Steel TP316 | 0.08% max | 2.00% max | 16.00% to 18.00% | 2.00% to 3.00% |
Mechanical Properties of Rectangular Finned Tubes
Grade | Tensile Strength (Min) | Yield Strength (Min) | Elongation (Min) |
|---|---|---|---|
Carbon Steel A179 | 325 MPa | 180 MPa | 35% |
Alloy Steel A213 T11 | 415 MPa | 205 MPa | 30% |
Stainless Steel TP304 | 515 MPa | 205 MPa | 35% |
Stainless Steel TP316 | 515 MPa | 205 MPa | 35% |
Rectangular Finned Tubes Dimension Chart
Bare Tube OD (per tube) | Fin Size (each side) | Fin Thickness |
|---|---|---|
25 mm to 38 mm | 50 mm to 75 mm | 2 mm to 3 mm |
42 mm to 51 mm | 75 mm to 95 mm | 3 mm to 4 mm |
51 mm to 65 mm | 95 mm to 130 mm | 3 mm to 4 mm |
Match your bare tube diameter against this chart for the standard fin size pairing.Share your drawing with our team if your project falls outside these ranges.
Applications of Rectangular Finned Tubes
- Economizers: coal and oil fired boiler units running long tube rows that benefit from the added rigidity.
- Waste Incinerator Heat Recovery: recovering heat from combustion gas in waste-to-energy plants.
- Utility and Industrial Boilers: tube banks where a single tube section would need extra support.
- Marine Power Plant Boilers: shipboard boiler applications requiring a compact, rigid finned section.
- Dust Laden or Fouling Flue Gas Service: the straight gas paths between fins resist fouling the same way the single tube version does.
Frequently Asked Questions
What is a rectangular finned tube?
A rectangular finned tube is the twin tube configuration of the H fin construction, built by welding fin plates across two base tubes positioned side by side, giving a wider and more rigid finned section than a single tube build.
What is the difference between a rectangular finned tube and a double H fin tube?
There is no difference. Rectangular Finned Tube, Double H Fin Tube, and HH-type Finned Tube are all names used across the industry for the same twin tube H fin construction. Amardeep's own Welded Square Fin Tubes page covers the single tube version of the same construction.
When should I choose a twin-tube rectangular finned tube instead of a single tube square fin tube?
Choose the twin tube version when your tube row is long enough that a single tube section would need additional structural support, or when the application specifically calls for the extra rigidity a Double H build provides, such as long economizer rows or waste incinerator heat recovery banks.
What is the maximum operating temperature for rectangular finned tubes?
Rectangular finned tubes are typically rated up to 300 degrees Celsius. The exact figure for your order depends on the base tube material, wall thickness, and the design code your equipment is built to.
Which materials are available for rectangular finned tubes?
Amardeep Steel Centre supplies rectangular finned tubes in carbon steel A179, A192, and A210; alloy steel A213 T5, T11, and T22; and stainless steel TP304 and TP316, matched to your process fluid and flue gas composition.
Does Amardeep provide Mill Test Certificates with Rectangular Finned Tubes?
Yes, every order of rectangular finned tubes ships with a mill test certificate covering the chemical and mechanical properties of the base tube and fin material used.
Request a quote for rectangular finned tubes
Get in touch with our team with your project specification, orsend an enquiry directly for a quote on Rectangular Finned Tubes built to your requirement.
Request a QuoteSimilar Products
Welded Square Fin Tubes, H Fin Tubes, G Fin Tubes, Finned Tubes, Heat Exchanger Tubes, and Condenser Tubes
