Serrated Fin Tubes for Fired Heaters – ASTM A213 TP304 Stainless Steel

Our serrated fin tubes for fired heaters are engineered heat-transfer components designed to improve thermal efficiency in industrial fired-heater convection sections. Manufactured using ASTM A213 TP304 austenitic stainless-steel base tubes, these products combine corrosion resistance, reliable mechanical properties, and an enlarged external heat-transfer surface.

Serrated fins are formed with regularly spaced cuts or slots along the fin edge. This segmented configuration helps disrupt the flue-gas boundary layer, promote turbulence, and improve heat transfer compared with a plain tube under suitable operating conditions. It also provides a practical balance between heat-transfer performance, mechanical strength, and material consumption.

These tubes can be supplied for new fired-heater construction, convection-bank replacement, heater revamping, and customized heat-recovery projects. Dimensions, fin geometry, and manufacturing details are tailored to the customer's engineering drawings and operating requirements.

Product highlights

• ASTM A213 TP304 seamless stainless-steel base tubes.

• Serrated fin geometry for enhanced gas-side heat transfer.

• Suitable for selected fired-heater convection-section applications.

• Customized fin height, pitch, thickness, and serration pattern.

• Options for different tube lengths, configurations, and end preparations.

• Inspection and material traceability documentation available.

Serrated fin tubes are primarily used where heat must be recovered from hot flue gas and transferred to process fluids flowing inside the tubes.

Typical applications include:

• Fired-heater convection sections: Recovering heat from combustion gases before they leave the heater.

• Petroleum refineries: Process heating systems, crude-oil preheaters, and selected refinery heater applications.

• Petrochemical plants: Feed preheating and process-fluid heating systems.

• Chemical processing facilities: Heat recovery and process heating equipment.

• Industrial furnaces: Customized convection banks and waste-heat recovery arrangements.

• Heater revamping projects: Replacing existing heat-transfer elements to improve thermal performance.

The final suitability of TP304 depends on actual metal temperature, flue-gas composition, oxidation and corrosion conditions, design pressure, and the applicable engineering code. For high-temperature radiant-section service or severe creep conditions, a higher-temperature alloy may be required.

A serrated fin tube consists of a pressure-bearing base tube and external metallic fins arranged helically around the tube surface.

The base tube carries the process fluid, while the external fins increase the heat-transfer area exposed to the hot flue gas. The serrated edges divide the fin into segments, disturbing the gas-side flow and helping reduce the thickness of the thermal boundary layer.

The resulting heat-transfer improvement depends on gas velocity, fin geometry, tube arrangement, fouling tendency, and operating temperature. The design must also account for gas-side pressure drop and cleaning requirements.

Main components

• Base tube: ASTM A213 TP304 seamless stainless steel.

• Fin material: TP304 stainless steel or another project-approved material.

• Fin configuration: Helically wound serrated strip.

• Fin attachment: Welding or another approved attachment method, according to the design.

• Tube ends: Plain, beveled, or otherwise prepared as specified.

The following dimensions are indicative manufacturing ranges, not mandatory dimensions prescribed by ASTM A213. Final dimensions should be confirmed against the customer's drawings, heat-transfer calculations, and fired-heater design requirements.

Other dimensions can be manufactured according to project specifications.

Available customization

• Different base tube diameters and wall thicknesses.

• Serration depth, width, and spacing.

• Fin height, pitch, and thickness.

• Right-hand or left-hand helical winding, where required.

• Customized tube lengths and end configurations.

• Special requirements for heater bundles and replacement assemblies.

ASTM A213 TP304 is an austenitic chromium-nickel stainless steel commonly identified by UNS S30400. Its chromium and nickel content provides general corrosion resistance and good fabrication characteristics.

Typical specification limits are shown below. Values are weight percentages (%).

The chemical composition of each production heat is verified against the applicable ASTM specification and reported in the material test certificate.

Important grade distinction: TP304 is not the same as TP304L or TP304H. TP304L has a lower maximum carbon content, while TP304H has a controlled higher carbon range and is intended for specified high-temperature applications. These grades should not be substituted without engineering approval.

The following are commonly specified minimum mechanical requirements for TP304 seamless tubing.

These values apply to the base tube under the relevant specification and test conditions. They should not automatically be treated as guaranteed properties of the finished finned assembly after fin attachment and fabrication.

Our serrated fin tubes are manufactured through a controlled production process to ensure dimensional consistency, fin attachment quality, and reliable performance.

Step 1 – Base tube selection

Seamless ASTM A213 TP304 tubes are selected according to the specified outside diameter, wall thickness, length, and material requirements.

Step 2 – Incoming material inspection

Material certificates, heat numbers, dimensions, surface condition, and material identification are checked before production.

Step 3 – Fin strip preparation

Stainless-steel fin strip is prepared to the specified thickness and width. Serrations are formed using controlled cutting or slitting operations.

Step 4 – Helical fin forming

The serrated strip is wound helically around the base tube according to the required fin height, pitch, and winding configuration.

Step 5 – Fin attachment

The fin is attached using the specified welding or approved manufacturing process. Welding parameters and workmanship are controlled to achieve consistent attachment quality.

Step 6 – Final inspection

Finished tubes are inspected for dimensions, fin alignment, attachment integrity, surface defects, and compliance with the approved drawings.

Step 7 – Cleaning and packaging

Products are cleaned as required, identified, protected against handling damage, and packed for transportation.

Quality control is performed at both the base-tube stage and the finished finned-tube stage. Inspection requirements are agreed according to ASTM A213, the applicable general requirements, and the customer's purchase specification.

ASTM A213 requires specified mechanical tests and either a nondestructive electric test or hydrostatic test for the base tubing. The precise inspection plan for the completed finned product should be defined in the purchase order. Additional weld examinations or fin-attachment tests may be agreed for critical service.

Improved heat-transfer performance

The increased external surface area provides more opportunity for heat exchange between flue gas and the process fluid. Serrated edges can also promote gas-side turbulence.

More effective convection-section heat recovery

Properly designed serrated fin tubes can help recover additional thermal energy from flue gas, supporting improved heater efficiency.

Corrosion resistance

TP304 stainless steel offers useful resistance to many atmospheric and process-related corrosive environments. Actual suitability must be evaluated against flue-gas contaminants and operating conditions.

Flexible engineering design

Fin height, pitch, thickness, serration pattern, tube diameter, and length can be adjusted to meet project requirements.

Suitable for replacement and revamping

Customized dimensions and configurations allow serrated fin tubes to be considered for fired-heater maintenance, replacement, and performance-improvement projects.

Depending on the purchase order, the following documentation can be supplied:

• Material Test Certificate (MTC), normally EN 10204 3.1 when requested.

• Chemical composition and mechanical test reports.

• Base-tube inspection records.

• Non-destructive testing reports, where applicable.

• Dimensional and fin geometry inspection reports.

• Fin attachment and welding inspection records.

• PMI reports, when specified.

• Product identification and traceability records.

• Packing list and certificate of conformity.

To obtain a quotation or technical proposal for serrated fin tubes for fired heaters, please provide:

1. Base tube material and applicable standard.

2. Tube outside diameter and wall thickness.

3. Tube length and required quantity.

4. Fin material and fin thickness.

5. Fin height, pitch, and serration dimensions.

6. Fin attachment or welding requirements.

7. Operating temperature, pressure, and process-fluid information.

8. Applicable inspection, testing, and documentation requirements.

9. Project drawings or technical specifications, if available.

Our technical team can review the supplied specifications and propose a manufacturing arrangement suitable for the intended fired-heater application.

Q1: What is a serrated fin tube used for in a fired heater?

Serrated fin tubes are generally installed in convection sections to increase the external heat-transfer area and improve heat recovery from hot flue gas.

Q2: What is the base tube material of this product?

The base tube is ASTM A213 TP304 seamless stainless steel. Alternative grades can be considered when required by the operating conditions and project specification.

Q3: Are serrated fin tubes suitable for high-temperature fired heaters?

They can be suitable for selected convection-section duties. However, TP304 is not automatically suitable for every high-temperature heater application. Metal temperature, creep strength, oxidation, carburization, and flue-gas chemistry must be evaluated before material selection.

Q4: Can you manufacture serrated fin tubes according to customer drawings?

Yes. Base tube dimensions, fin height, pitch, thickness, serration geometry, tube length, and attachment requirements can be customized according to approved drawings.

Q5: What is the difference between plain fin tubes and serrated fin tubes?

Plain fin tubes have continuous fin edges, while serrated fin tubes have segmented or cut fin edges. Serrations can disturb gas flow and improve heat-transfer characteristics, although the actual benefit depends on the design and operating conditions.

Q6: What inspection documents are available?

Material certificates, chemical and mechanical test reports, dimensional inspection records, and applicable NDT or fin-attachment inspection reports can be provided according to the order requirements.