WELDED FINNED TUBE

High Frequency Welded Finned Tubes

Reliable. Durable. Proven Since 1964.

At Petromarsh, we proudly offer Spiro-Gills’ High Frequency Welded Finned Tubes, trusted by global industries for use in boilers, air-cooled heat exchangers, and thermal process systems. These tubes are manufactured using a continuous, high-frequency electric resistance welding (ERW) process, ensuring an exceptionally strong bond between the fin and the tube for long-term performance—even under the most demanding conditions.

Our Trusted Partner: Spiro-Gills Products Ltd

World-Class Manufacturer of Welded Finned Tubing

At Petromarsh, we are proud to partner with Spiro-Gills Products Ltd, the UK’s largest and most respected manufacturer of extended surface finned tubing. Spiro-Gills has a global reputation for engineering excellence, supplying high-performance welded finned tubes to over 100 countries worldwide.

Global Expertise in Heat Transfer Technology

Spiro-Gills’ finned tubes are critical components in:

Heat recovery systems for boilers and gas turbines
Power generation facilities
Petrochemical and furnace applications
Air-cooled heat exchangers and waste heat recovery units

Manufactured using precision high-frequency welding techniques, the fins are helically wound around the tube to maximize heat transfer efficiency. Fin types are available in plain or serrated configurations, tailored to the thermal and mechanical demands of your application.

Decades of Proven Performance

With roots dating back to 1945 and continuous innovation in welded fin tube manufacturing since 1964, Spiro-Gills brings more than 50 years of unmatched industry experience. Their equipment and solutions are found across virtually every major industrial sector—from offshore energy platforms to inland power plants.

Why Choose Spiro-Gills Through Petromarsh?

Short production lead times to minimize downtime
Wide selection of material combinations for demanding environments
ISO-compliant quality control and full traceability
Customization options to meet exact thermal specifications

Whether you're sourcing for a new build or replacing aging components, Petromarsh and Spiro-Gills deliver finned tube solutions that combine efficiency, durability, and reliability at competitive pricing.

THE TYPES OF FINNED TUBE

SERRATED FIN

Fin Height: 0.5–1.5” (12.7–38.1mm)

(higher on application)

Fin Thickness: 0.036–0.05” (0.9–1.27mm)

Fin Spacing: 1–7 per inch (39–276 per metre)

Tube Outside Diameter: 0.75–8” (19.05–219.1mm) Segment Width: 5/32, 5/16” (4.5, 8.0mm)

PLAIN FIN (SOLID FIN)

Fin Height: 0.25–1.0” (6.4–25.4mm)

(higher on application)

Fin Thickness: 0.036–0.098” (0.9–2.5mm)

Fin Spacing: 1–7 per inch (39–276 per metre)

Tube Outside Diameter: 0.75–8” (19.05–219.1mm)

High-Frequency Resistance Welding (HFRW) for Finned Tubes

Advanced Welding Technology for Superior Heat Transfer Efficiency

At Petromarsh, we utilize advanced high-frequency resistance welding (HFRW)—a process that operates at frequencies around 450,000 Hz—to deliver exceptional quality finned tube assemblies for demanding heat exchanger applications.

How It Works: Precision Welding for Performance

In this method, a helical (edge-wound) fin is continuously wrapped around the tube while a high-frequency electric current is applied. The resistance at the contact interface between the fin and tube generates localized heat. This heat, combined with applied pressure, forges the fin to the tube, producing a strong metallurgical bond with excellent heat transfer characteristics.

Key Advantages of HFRW

Wide Contact Surface: The welding process slightly upsets (widens) the fin base, resulting in a broader contact area than the fin thickness, which maximizes thermal conductivity.
Full-Surface Heat Transfer: Heat is conducted across the entire fin-to-tube interface, not just the weld seam, reducing thermal resistance.
Localized Heating: The high-frequency current targets only the fin edge and tube surface, minimizing the heat-affected zone (HAZ) and preserving material integrity.
Thicker Fin Capability: HFRW supports the welding of thicker fins previously limited to more expensive MIG, TIG, or stud welding methods.
Continuous Cooling: Water cooling around the tube during welding keeps the material temperature low outside the weld zone, preventing distortion or metallurgical degradation.

Material Compatibility and Metallurgical Stability

The HFRW process is compatible with most carbon steel, stainless steel, and alloy tubing. It maintains minimal grain structure changes in the tube wall, preserving mechanical properties.

⚠️ Note: Some chromium steels (3% to 9% Cr) may experience a transition from ferritic to martensitic microstructure in the HAZ, which can lead to increased hardness. Special consideration should be taken during material selection.

Why Choose HFRW Finned Tubes from Petromarsh?

Improved durability under thermal stress
High-speed, high-precision production
Cost-efficient vs. traditional welding methods
Reliable heat transfer performance over time
Minimal distortion, even with complex material pairings

Our investment in McElroy and Thermatool high-frequency welding equipment ensures consistent, repeatable, and industry-leading weld quality.

Looking for a quote or technical advice?
Our thermal and mechanical engineers can guide you through the right fin geometry, tube material, and welding method to match your heat exchanger design.

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Weld Quality in Finned Tube Manufacturing

Precision Welding for Maximum Heat Transfer and Durability

At PetroMarsh, we combine advanced high-frequency resistance welding (HFRW) technology with deep operator expertise to deliver finned tubes of exceptional quality. While automated welding processes have enhanced productivity and consistency, the skill of the technician remains critical, particularly when dealing with complex alloys and demanding specifications in the power generation, chemical, and petroleum sectors.

Indicators of Weld Integrity

During visual inspection, several features indicate a high-quality weld:

Oxide Expulsion: Achieving proper fusion requires displacement of oxide layers from both the fin and tube. This typically results in slight oxide expulsion along both fin edges, a sign that strong metallurgical bonding has occurred.
Base Corrugation: Excessive corrugation at the base of the fin is a sign of poor weld tooling setup and can compromise thermal efficiency. At PetroMarsh, our custom tooling designs minimize corrugation to maintain optimal contact and performance.
Serrated Fin Option: For applications where weld quality is paramount, we recommend serrated or segmented fins, which eliminate many forming and bonding challenges associated with plain helical fins. These also enhance turbulence and heat transfer.

Minimizing Pressure Drop Across Finned Tubes

Engineered for Efficient Airflow and Low Resistance

The shape and placement of the fin directly affect pressure drop, especially in air-cooled heat exchangers. Poorly aligned or deformed fins can restrict airflow and lead to increased operational costs.

To ensure optimal performance, our finned tubes are designed to:

Maintain perpendicularity: The fin must stand upright relative to the tube. Leaning fins block airflow, reducing the free-flow area and increasing pressure drop. We manufacture to tight tolerances, adhering to strict quality standards.
Minimize base corrugation: A smooth fin-to-tube transition ensures minimal turbulence and flow disruption. Our tooling and process control are optimized to suppress corrugation.
Use serrated fins where applicable: In challenging geometries or corrosive environments, segmented fins maintain flow uniformity and structural integrity with less susceptibility to distortion.

UK’s Leading Manufacturer of Finned Tubes

PetroMarsh, in partnership with Spiro-Gills Products, is the only UK manufacturer of both welded and applied finned tubes. We produce high-specification tubes from 25mm to 219mm diameter, suitable for:

Process and engine cooling systems
Waste heat boilers and economizers
Petrochemical furnace applications
Power generation and refinery heat recovery

Need a custom solution or urgent delivery?
We offer short lead times, a full range of materials (carbon steel, stainless, alloy), and rapid turnaround for planned shutdowns or emergency requirements.

Let PetroMarsh help you optimize heat transfer while minimizing operational losses. Contact us today for a detailed quote or engineering consultation.

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