Welded Square Fin Tubes Manufacturer in India
Welded Square Fin Tubes, also known as H Fin Tubes or Square Finned Tubes, are designed for waste heat recovery applications where gas streams contain dust, ash, or other fouling particles. Their rigid fin construction provides the durability required for demanding industrial heat-transfer service. Amardeep Steel Centre supplies custom-built Welded Square Fin Tubes manufactured to ASME and EN heat exchanger standards. Tube dimensions, fin geometry, pitch spacing, materials, and other specifications can be customized to suit individual heat exchanger and boiler requirements.
Send us your tube bank drawing for a rapid engineering review. Our technical team will verify the design requirements and provide a detailed quotation within one working day.
What Are Welded Square Fin Tubes
A Welded Square Fin Tube is manufactured from a plain bare tube fitted with two rectangular fin plates on opposite sides. The inner edge of each fin plate is pre-cut with a curved profile matching the tube's outer diameter, allowing the plates to sit securely against the tube before welding. The fin plates are joined to the tube using resistance welding, where electrical current generates localized heat at the contact points while pressure is applied to form the joint. This produces a strong metallurgical bond with a relatively small heat-affected zone.
The finished tube has an H-shaped cross section, which is why it is commonly called an H Fin Tube. A standard tube with this configuration is referred to as a Square Fin Tube. For applications requiring additional structural rigidity or heat-transfer surface, two tubes can be combined with the fins positioned between them, creating a double H Fin Tube or twin-tube configuration.
Technical Data
Specifications of Welded Square Fin Tubes
| Parameter | Specification |
|---|---|
|
Fin Type |
Square, H type, resistance welded |
|
Base Tube Material |
Carbon Steel, Alloy Steel, Stainless Steel |
|
Fin Material |
Carbon Steel, Alloy Steel, Stainless Steel, matched to base tube |
|
Bare Tube Outer Diameter |
25 mm to 65 mm, larger sizes available on request |
|
Minimum Tube Wall Thickness |
3 mm |
|
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, exact pitch confirmed against tube bank drawing |
|
Tube Configuration |
Single tube square fin, or twin tube double H fin |
|
Documentation |
Mill Test Certificate supplied with every order |
Chemical Composition of Welded Square Tubes
| Grade | C | Mn | Si | Cr | Ni | Mo | P | S |
|---|---|---|---|---|---|---|---|---|
|
Carbon Steel A179 |
0.06% to 0.18% |
0.27% to 0.63% |
0.035% max |
0.035% max |
||||
|
Alloy Steel A213 T11 |
0.05% to 0.15% |
0.30% to 0.60% |
0.50% to 1.00% |
1.00% to 1.50% |
0.44% to 0.65% |
0.025% max |
0.025% max |
|
|
Stainless Steel TP304 (A213) |
0.08% max |
2.00% max |
0.75% max |
18.00% to 20.00% |
8.00% to 10.50% |
0.045% max |
0.030% max |
|
|
Stainless Steel TP316 (A213) |
0.08% max |
2.00% max |
0.75% max |
16.00% to 18.00% |
10.00% to 14.00% |
2.00% to 3.00% |
0.045% max |
0.030% max |
Carbon steel A179 base tubes suit clean flue gas service at moderate temperatures. Alloy steel T11 base tubes hold up better at higher boiler duty temperatures thanks to the added chromium and molybdenum. TP304 and TP316 stainless steel base tubes are worth specifying wherever the flue gas condensate turns corrosive, with TP316 giving the extra margin where chlorides are present.
Mechanical Properties of Welded Square Finned Tubes
| Grade | Tensile Strength | Yield Strength | Elongation |
|---|---|---|---|
|
Carbon Steel A179 |
325 MPa min |
205 MPa min |
35% min |
|
Alloy Steel A213 T11 |
415 MPa min |
205 MPa min |
30% min |
|
Stainless Steel TP304 |
515 MPa min |
205 MPa min |
35% min |
|
Stainless Steel TP316 |
515 MPa min |
205 MPa min |
35% min |
Dimension Chart of Welded Finned Tubes
| Bare Tube OD | Fin Size (each side) | Fin Thickness | Fin Spacing |
|---|---|---|---|
|
25 mm to 38 mm |
50 mm to 75 mm |
2 mm to 3 mm |
12.7 mm to 20 mm |
|
42 mm to 51 mm |
75 mm to 95 mm |
3 mm to 4 mm |
15 mm to 25 mm |
|
51 mm to 65 mm |
95 mm to 130 mm |
3 mm to 4 mm |
20 mm to 30 mm |
Match your bare tube diameter against this chart to get a rough sense of the fin geometry you will need. Fin size and spacing are always confirmed against the actual tube bank or economizer layout before production starts, since these tubes are built to the equipment, not pulled off a standard stock list. Share your drawing with our team and we will confirm exact dimensions for your project.
Welded Square Fin Tube Working Pressure and Operating Temperature
| Parameter | Typical Rating |
|---|---|
|
Maximum Operating Temperature |
Up to 300 deg C |
|
Atmospheric Corrosion Resistance |
Good, improves further with a stainless steel base tube |
The exact pressure rating for your Welded Square Fin Tube order depends on the base tube material, wall thickness and the design code your economizer or boiler is built to. Send us your process conditions and we will confirm the working pressure and temperature rating before you finalise the tube bank design.
How Welded Square Fin Tubes Differ from H Fin Tubes and G Fin Tubes
| Feature | Welded Square Fin Tubes / H Fin Tubes | G Fin Tubes |
|---|---|---|
|
Product Construction |
Resistance-welded fin forming an H-shaped cross section |
Fin is embedded into a helical groove machined into the tube |
|
Fin Attachment |
Fin is welded directly onto the tube surface |
Fin is mechanically locked into the grooved tube |
|
Cross-Section |
H-shaped |
G-shaped / grooved construction |
|
Manufacturing Method |
Resistance welding |
Helical grooving and mechanical embedding |
|
Product Equivalence |
Welded Square Fin Tube and H Fin Tube describe the same product |
Different construction from welded/H fin tubes |
|
Temperature Range |
Suitable for applications requiring welded fin construction |
Offers a different temperature range due to its mechanically embedded fin design |
|
Typical Application |
Better suited to fouling flue gas duty |
Better suited to continuous-duty air-cooled service |
|
Fin Stability |
Fin is securely attached through resistance welding |
Fin is mechanically secured within the tube groove |
|
Suitable Service |
Industrial heat transfer applications, particularly fouling flue gas environments |
Continuous air-cooled heat transfer applications |
|
When to Choose |
Choose when your equipment specification calls for H Fin Tubes or welded square fin tubes |
Choose when the application requires G Fin Tube construc |
Applications of Welded Square Fin Tubes
- Economizers in coal and oil fired boiler units
- Utility and industrial boilers
- Heat Recovery Steam Generator (HRSG) systems
- Ship and marine power plant boilers
- Industrial kilns and furnaces
- Dust laden or fouling flue gas service, where the straight gas paths between fins are easier to clean than a spiral wound fin
Welded Square Fin Tubes are frequently specified alongside heat exchanger tubes and condenser tubes in the same waste heat recovery system, since the economizer section and the condenser section often share a common tube bank layout.
Available Materials
Welded Square Fin Tubes from Amardeep Steel Centre are available in the following base tube materials, matched to your flue gas composition and operating temperature:
Frequently Asked Questions
What are Welded Square Fin Tubes?
Welded Square Fin Tubes are finned tubes made by resistance welding two rectangular fin plates onto opposite sides of a bare tube, forming an H shaped cross section that gives the tube its alternative name, H Fin Tube.
How are Welded Square Fin Tubes different from H Fin Tubes?
They are the same product. Welded Square Fin Tube and H Fin Tube both describe a resistance welded fin forming an H shaped cross section, and the two names are used interchangeably across the industry.
How are Welded Square Fin Tubes different from G Fin Tubes?
A Welded Square Fin Tube has its fin welded onto the tube surface. A G Fin Tube has its fin embedded into a machined groove in the tube and mechanically locked in place. The two constructions suit different duties, with square fin tubes built for fouling flue gas service and G fin tubes built for continuous duty air cooled service.
What is the difference between a single square fin tube and a double H fin tube?
A single square fin tube uses one bare tube with fins welded on both sides. A double H fin tube welds fins between two bare tubes, giving extra structural rigidity for longer tube rows.
What is the maximum operating temperature for Welded Square Fin Tubes?
Welded Square Fin Tubes are typically rated for continuous service up to 300 deg C. Exact ratings depend on the base tube material, wall thickness and the design code your equipment is built to, so confirm project specific figures with our team.
Which materials are Welded Square Fin Tubes available in?
Amardeep Steel Centre supplies Welded Square Fin Tubes in Carbon Steel A179, Alloy Steel A213 T11, and Stainless Steel TP304 and TP316, matched to your process fluid and flue gas composition.
What industries use Welded Square Fin Tubes?
Welded Square Fin Tubes are widely used in economizers, utility and industrial boilers, HRSG systems, marine boilers, industrial kilns and furnaces, and any dust laden or fouling flue gas application where straight fin channels are easier to keep clean.
Does Amardeep provide Mill Test Certificates with Welded Square Fin Tubes?
Yes, every order of Welded Square 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
- G fin tubes
- finned tubes
- crimped finned tubes
- helical serrated finned tubes
- helical solid finned tubes
- helically wound high fin tubes
- shoulder tension finned tubes
Request a quote for Welded Square Fin Tube
For a wider look at our tube range, see our finned tubes hub page and heat exchanger tubes product line. Get in touch with our team with your process conditions, or send an enquiry directly for a quote on Welded Square Fin Tubes built to your specification.
