What is a High Frequency Welded Solid Finned Tube
High Frequency Welded Solid Finned Tubes are specialized heat exchange components that combine a base tube with external fins through high-frequency welding technology. These tubes are designed to significantly enhance heat transfer efficiency by increasing the surface area available for thermal exchange. The high-frequency welding process creates a strong metallurgical bond between the fins and the base tube, making them suitable for demanding industrial applications. This process leverages the skin effect to generate localized heating at the fin-tube interface, achieving temperatures of 800-1300°C within 0.1-0.5 seconds. The subsequent pressure welding creates a molecular-level bond with >95% weld integrity.
The Key Features of a High Frequency Welded Solid Finned Tube
Structure:
- Base Tube: Typically carbon steel tubes, stainless steel tubes, or alloy steel tubes.
- Fins: Solid metal strips (not hollow) welded tightly to the tube.
- Bonding Method: High-frequency welding creates a metallurgical bond between the fin and tube, ensuring minimal thermal resistance.
How It Works:
- High-frequency electrical currents generate localized heat, melting the fin and tube surfaces.
- Pressure is applied to fuse the materials, forming a seamless and durable joint.
One of the key design features of high-frequency welded solid fin tubes is the continuous weld line that runs along the entire length of the fin-to-tube interface. This creates a strong, uniform bond that can withstand thermal cycling and mechanical stresses better than other attachment methods. The fins are usually spaced closely together to maximize surface area while maintaining adequate flow channels for the heat transfer medium.
The Manufacturing Process of A High Frequency Welded Solid Finned Tube
Material Preparation
- Base Tube Selection: Carbon steel pipes, stainless steel pipes (304/316), or seamless steel pipes are selected for their mechanical strength and compatibility with high-frequency welding.
- Fin Strip Material: Aluminum fins or steel strips (0.3–1.2 mm thickness) are precision-cut to match the base tube dimensions.
Pre-Treatment
- Surface Cleaning: Base tubes undergo degreasing and pickling to remove oxides, ensuring optimal welding surface conditions.
- Fin Strip Alignment: Strips are helically wound around the base tube with controlled tension to maintain uniform spacing.
High-Frequency Welding
- Induction Heating: High-frequency current (100–400 kHz) generates localized heat at the fin-tube interface, melting the fin strip edge and bonding it to the base tube.
- Pressure Rolling: Simultaneous mechanical pressure (10–30 MPa) ensures metallurgical bonding without filler materials.
Rapid Cooling
- Water cooling is typically employed, where water at 20–30°C is sprayed (flow velocity of 1.5–2 m/s) to achieve rapid cooling. The cooling time is controlled within 1–3 seconds to ensure the molten metal solidifies quickly.
How to Control the Quality of A High Frequency Welded Solid Finned Tube
Quality Control of Raw Materials
- Before finning, steel tubes and fin strips shall be visually inspected for identification and to check if any defects incompatible with finning operations still remain.
Welding Control of Finned Tubes
- Welding should be carried out in accordance with the WPS and PQR approved by the customer.
- During the welding, finned tubes shall be random controlled in order to check the welding quality and the geometrical characteristics. Spot examination shall be carried out at least on one out of 10 tubes. If anomaly is detected, the 9 previous tubes shall be examined again. Examination shall be extended if anomaly and/or defects are confirmed.
Visual and Dimension Check of Finned Tubes
- the following dimensions shall be checked: straightness of finned tube, total length of finned tube, bare length of finned tube, pitch of finned tube, fin height, fin thickness, fin perpendicularity, etc.
The Advantages of A High Frequency Welded Solid Finned Tube
Superior Thermal Conductivity
- The solid metallurgical bond between fin and base tube eliminates the thermal resistance found in mechanically attached fins, resulting in higher heat transfer efficiency.
High Temperature Resistance
- The welded construction allows these tubes to operate at much higher temperatures than fin types that rely on mechanical interference or adhesives.
Mechanical Strength
- The fins are securely attached and can withstand vibration, thermal cycling, and other mechanical stresses better than other fin types.
Long-Term Reliability
- Unlike fin types that may loosen or degrade over time, high-frequency welded fins maintain their performance characteristics throughout the service life of the equipment.
Design Flexibility
- The process allows for a wide range of fin heights, thicknesses, and materials to be used, enabling customization for specific applications.
Compact Design
- The high heat transfer efficiency allows for more compact heat exchanger designs, saving space and material costs.
Corrosion Resistance
- When made from appropriate materials, these tubes offer excellent resistance to various corrosive environments common in industrial applications.
Performance studies have shown that properly designed high-frequency welded solid finned tubes can increase heat transfer rates by 30-50% compared to bare tubes of the same size, while maintaining reasonable pressure drop characteristics. This makes them an excellent choice for applications where space and weight constraints are important considerations.
The Disadvantages of A High Frequency Welded Solid Finned Tube
Limited Material Compatibility
- Base tubes and fins must have similar melting points and thermal expansion coefficients (e.g., steel-steel or steel-copper). Aluminum fins are challenging to weld to steel due to metallurgical incompatibility.
Mechanical Stress Sensitivity
- Residual stresses from localized heating weaken fin roots, risking fatigue cracks under cyclic thermal loads (common in boilers and heat exchangers).
High Equipment Costs
- High-frequency power generators and precision alignment systems raise upfront investment (20–30% higher than extrusion or embedded fin methods).
Fin Height Restrictions
- Max fin height typically ≤20 mm due to uneven heat distribution during welding. Exceeding this limit reduces bond strength by 15–20%.
Process Complexity
- Strict parameter control (e.g., 200–400 kHz frequency, 10–30 MPa pressure) is required. Minor deviations cause defects like porosity or incomplete fusion.
Sizes and Materials of Our High Frequency Welded Solid Finned Tubes
| Base Tube Diameter | 16 to 350 mm | 3/8″ to 14″ NPS |
| Base Tube Wall Thickness | 2 to 30 mm | 0.08″ to 1.18″ |
| Base Tube Length | ≤32,000 mm | ≤92 ft |
| Base Tube Material | Carbon Steel (A106B, P235GH, A179, A210, A192, etc.) Alloy Steel (P5, T5, P9, T9, T11, T22, etc.) Stainless Steel (TP304, TP316, TP347, B407 800H/HT, etc.) | |
| Fin Pitch | 39 to 277 FPM | 1 to 7 FPI |
| Fin Height | 8 to 35 mm | 0.31″ to 1.38″ |
| Fin Thickness | 0.5 to 3 mm | 0.02″ to 0.12″ |
| Fin Material | Carbon Steel, 2.25Cr-1Mo, 5Cr-0.5Mo, 11-13Cr (409, 410), 18Cr-8Ni (SS 304), 25Cr-20Ni, aluminum | |
| Fin Type | Solid | |
For other customized requirements, please contact us.
What is the Price of A High Frequency Welded Solid Finned Tube
Please contact our sales manager Allen@sanesteel.com.
Our Production Capacity of High Frequency Welded Solid Finned Tubes
Total four high frequency welded spiral finned tube machines, monthly production capacity is 1200 tons in total.
High Frequency Welded Solid Finned Tubes Uses
High Frequency Welded Solid Finned Tubes find widespread use in various industrial heat exchange applications where efficient thermal transfer is critical:
Power Generation: These finned tubes are extensively used in finned tube boilers, finned tube economizers, finned tube condensers, finned tube radiators, finned tube evaporators, and finned tube air preheaters in power plants. Their ability to withstand high temperatures and pressures makes them ideal for steam generation and power cycle equipment.
Petrochemical Industry: In refineries and chemical plants, they are employed in finned tube process heaters, finned tube reformers, and waste heat recovery systems where corrosion resistance and thermal efficiency are paramount.
HVAC Systems: Large commercial and industrial heating, ventilation, and air conditioning systems utilize these tubes in finned tube air coolers and finned tube chillers for their compact design and high heat transfer rates.
Waste Heat Recovery: Finned tubes play a crucial role in capturing and utilizing waste heat from industrial processes, improving overall energy efficiency and reducing environmental impact.
Marine Applications: Shipboard finned tube boilers and finned tube heat exchangers benefit from the durability and compactness of high-frequency welded solid finned tubes in the challenging marine environment.
One particularly important application is in Heat Recovery Steam Generators (HRSGs) used in combined cycle power plants. Here, these finned tubes help maximize energy recovery from exhaust gases, significantly improving plant efficiency. Their performance in such critical applications has driven continuous improvements in design and manufacturing techniques.
Comparison with Other Finned Tubes
| Type | Bonding Method | Fin Type | Typical Use |
| HFW Solid Spiral Finned Tube | Welded (HF current) | Solid metal | High-stress environments |
| HFW Serrated Spiral Finned Tube | Welded (HF current) | Serrated metal | High-stress environments |
| Laser Welded Finned Tube | Welded (Laser) | Solid metal | High-stress environments |
| Extruded Finned Tube | Mechanically bonded | Hollow fins | Moderate-temperature use |
| Embedded Finned Tube | Rolled into grooves | G/L-shaped fins | Low-pressure systems |
Maintenance and Operational Considerations
To ensure optimal performance and longevity of High Frequency Welded Solid Finned Tubes in service, several maintenance and operational practices should be followed:
Regular Inspection: Periodic visual and non-destructive inspection of finned tubes can help identify issues such as corrosion, fouling, or mechanical damage early.
Cleaning Protocols: Depending on the application, appropriate cleaning methods (mechanical, chemical, or thermal) should be employed to remove deposits that could impair heat transfer.
Operational Parameters: Operating within the designed temperature and pressure limits is crucial to prevent premature failure of the finned tubes.
Corrosion Protection: In corrosive environments, implementing proper corrosion protection measures can significantly extend service life.
Repair Techniques: For damaged finned tubes, specialized repair techniques may be available to restore functionality without full replacement.
Properly maintained high-frequency welded solid finned tubes can provide many years of reliable service, making them a cost-effective solution for industrial heat exchange needs despite their higher initial cost compared to some alternatives.
Why Choose Us
- a 16-year finned tube manufacturer. We are experts.
- solutions for all finned tube prouducts
- the highest product quality
- the low lead times
- excellent customer service
