H/HH Type High Frequency Welded Finned Tubes for Heat Exchangers with High Thermal Efficiency and Low Wear and Fouling
Product Details
High Thermal Efficiency Finned Tubes
,Low Wear Heat Exchanger Tubes
,Low Fouling H/HH Type Fin Tube
H/HH Type High-Frequency Welded Fin Tubes for Heat Exchangers
H/HH type high-frequency welded finned tubes are rectangular (H-shaped) or double-rectangular (HH) plate-finned tubes used as compact, high-efficiency heat-transfer elements in economizers, air preheaters and other gas-to-fluid heat exchangers. Two steel plates are resistance-welded to opposite sides of a round base tube, forming an “H” cross-section that greatly increases external surface area while creating straight flue-gas channels with low pressure drop and good soot-blowing accessibility.
Specifications
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Base tube OD: 25–63 mm (other diameters on request)
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Base tube wall thickness: ≥ 3.0 mm for boiler service
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Maximum length: up to about 18 m per tube (depends on grade and handling limits)
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Fin height: up to approx. 200 mm
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Fin thickness: 1.5–3.5 mm
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Fin spacing (pitch): typically 8–30 mm
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Base tube materials: carbon steel, low-alloy steel, Cr-Mo alloy steel, austenitic stainless steel
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Fin materials: carbon steel, low-alloy steel or stainless steel to match service conditions
Key Advantages
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High thermal efficiency in a compact bundle
The rectangular H/HH plate fins provide several times the heating surface of a plain tube economizer of the same diameter and length, enabling much smaller, lighter heat-exchanger banks. -
Low wear, low fouling in dusty flue gas
H-type fin tubes are widely used for coal-fired units, CFB boilers and waste-incinerator economizers because the straight channels and expanded gas-flow area help reduce gas velocity, erosion and ash deposition compared with smooth or spiral-finned tubes. -
Robust high-frequency welded fin-to-tube bond
Automatic high-frequency resistance welding produces a continuous metallurgical bond along the fin edge with minimal heat-affected zone, giving high tensile strength at the joint and excellent resistance to vibration, thermal cycling and soot-blowing.
Chemical Composition
| Grade | Standard | C (wt%) | Si (wt%) | Mn (wt%) | P max (wt%) | S max (wt%) | Notes |
|---|---|---|---|---|---|---|---|
| A179 | ASTM A179/A179M | 0.06–0.18 | not specified | 0.27–0.63 | 0.035 | 0.035 | Low-carbon seamless heat-exchanger tube |
| A192 | ASTM A192/A192M | ≤0.08 | ≤0.25 | 0.30–0.60 | 0.035 | 0.025 | Carbon steel boiler tube for high-pressure service |
| A210 Gr. A1 | ASTM A210/A210M | ≤0.27 | ≥0.10 | ≤0.93 | 0.035 | 0.035 | Seamless medium-carbon boiler and superheater tube |
| 20G | GB 5310 | 0.17–0.23 | 0.17–0.37 | 0.35–0.65 | 0.025 | 0.015 | Chinese high-pressure boiler tube steel |
| P235GH | EN 10216-2 (1.0345) | ≤0.16 | ≤0.35 | ≤1.20 | 0.025 | 0.020 | Non-alloy pressure-tube steel for elevated temperature |
Values are ladle analysis limits from the respective standards; actual mill test results are typically within these ranges.
Mechanical Properties
| Grade | Condition / Product form | Tensile strength Rm (MPa) | Yield strength Re / Rp0.2 (MPa) | Elongation A (%) |
|---|---|---|---|---|
| A179 | Seamless, cold-drawn tube | ≥325 | ≥180 | ≥35 |
| A192 | Seamless boiler tube | ≥325 | ≈205 (typical minimum) | ≥30 (8 in) / ≥25 (2 in) |
| A210 Gr. A1 | Seamless boiler tube | ≥415 | ≥255 | ≥30 |
| 20G | Normalized tube | 410–550 | ≥245 | ≥24 |
| P235GH | Normalized tube, T ≤ 16 mm | 360–500 | ≥235 | ≥25 |
Applicable Standards
Base tubes for H/HH finned tubes are typically produced to:
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ASTM / ASME: A179, A192, A210, A213 series for boiler and heat-exchanger tubes
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EN: EN 10216-2 grades such as P235GH, P265GH for pressure service at elevated temperature
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GB: GB/T 5310 high-pressure boiler tubes (e.g., 20G)
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JIS / GOST: Equivalent boiler and pressure-tube grades as required by project specifications
Typical Applications
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Power and industrial boilers: economizers, low-temperature economizers, air preheaters, waste-heat boilers
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Waste-heat recovery: tail-flue gas coolers on coal-fired, oil-fired and waste-incineration units, CFB boilers and process furnaces
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Process and marine sectors: fired-heater convection sections, process-gas coolers and marine exhaust-gas economizers using dust-laden, high-temperature gases
Q: Are you trading company or manufacturer ?
A: manufacturer,also can do trading.
Q: How long is your delivery time?
A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,
it is according to quantity.
Q: Do you provide samples? is it free or extra ?
A: Yes, we could offer the sample for free charge but need pay the cost of freight.
Q: What is your terms of payment ?
A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.
If you have another question, pls feel free to contact with me.
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