The weld never stops. High-frequency current concentrates heat into a narrow line where fin strip meets tube, fusing the two continuously as the tube spins past at production speed: no filler metal, no groove, and a steel-to-steel bond running the whole helix. That continuous weld is why HF finned tubes own the hottest strip-fin duties, fired heater convection sections, HRSGs, and waste heat boilers, where wrapped and embedded fins let go long before. USA Piping Solution supplies high frequency welded finned tubes in solid and serrated form on carbon, alloy, and stainless base tube. The full fin construction map is on our Finned Tubes page.
Specifications
| Specification | Details |
|---|---|
| Base Tube | Carbon steel (A106/A192/A210), alloy steel (A213 T11/T22/T91 on request), stainless (A213/A249) |
| Fin Material | Carbon steel, alloy steel, or stainless strip, matched to duty |
| Fin Forms | Helical solid · helical serrated (segmented) |
| Base Tube OD | Typically 25 – 219 mm |
| Fin Geometry | Height commonly 9 – 25 mm, thickness 0.8 – 3 mm, 2 – 7 fins per inch |
| Service | Set by base tube and fin alloy; the weld itself is not the limiting element |
Why the HF Weld Matters
A fin joint is only as good as its worst service day. Tension-wound fins (L type) relax with heat; embedded fins (G type) hold to roughly 400°C. The HF weld is a true metallurgical bond with no foreign filler, so the fin-to-tube joint carries whatever the base metals carry, which puts HF finned tube into fired heater and boiler convection duty that no mechanical attachment survives. It also welds fin alloys that match the duty: carbon steel fin on carbon tube, alloy on alloy, stainless on stainless.
Applications
- Fired Heater Convection Sections: refinery and petrochemical process heaters.
- HRSGs: heat recovery steam generators behind gas turbines, serrated fin's signature duty.
- Boiler Economizers & Air Heaters: utility and industrial units; bare pressure parts on Boiler & Heat Exchanger Tubes.
- Waste Heat Recovery Units: high-temperature industrial exhaust.
For ash so heavy that even solid HF fin plugs, the geometry change is H fin; for studs instead of fins entirely, see Stud Welded Tubes.
Send Fuel, Gas Temperature & Bank Layout →
Testing, Certification & Availability
Base tube ships to its ASTM standard with mill certification and heat traceability; fin weld continuity, pull-off strength, and geometry are inspected on the finned product; our Quality Policy page covers the program. Send base tube spec, fin form and geometry, and quantities for lead time.
Related Products
- Finned Tubes (all types)
- H Fin Tubes
- Stud Welded Tubes
- Carbon Steel Finned Tubes
- Stainless Steel Fin Tubes
Frequently Asked Questions
Is HF welded the same as ERW finned tube?
Same principle, high-frequency electric resistance welding, applied to the fin-to-tube joint. Specifications may write it as HF, HFW, or high frequency resistance welded finned tube; all describe this product.
Solid or serrated for an HRSG?
Serrated, almost always: gas turbine exhaust is clean, so serrated's extra turbulence buys a more compact bank with no fouling penalty. Solid earns its place when the fuel brings ash.
Can the fin be a different alloy than the tube?
Yes, within weldable combinations: carbon fin on alloy tube is common in economizers, stainless fin on carbon tube where gas-side corrosion outpaces the fluid side. State both sides of the duty and we'll match the pair.