ASME SA106 GR.B ASTM A106 GR.B STUDDED FIN TUBE FOR BOILERS HEAT EXCHANGERS AND FIRED HEATERS
A studded fin tube is a type of heat exchanger tube designed to enhance heat transfer efficiency. It consists of a seamless carbon steel base tube with small studs or fins resistance-welded onto its outer surface. These studs increase the surface area of the tube, allowing for improved heat transfer between the fluid inside the tube and the surrounding environment. The studs also create turbulence in the fluid flow, which helps to break up the boundary layer and further enhance heat transfer. This design is commonly used in applications where high heat transfer rates are required, such as in boilers, air coolers, fired heaters, economizers, and heat exchangers.
ASME SA106 Gr.B / ASTM A106 Gr.B is a specification for seamless carbon steel pipe intended for high-temperature service. The "Gr.B" grade signifies a minimum yield strength of 35,000 psi (240 MPa) and a minimum tensile strength of 60,000 psi (415 MPa), making it suitable for elevated temperature and pressure applications. When SA106 Gr.B material is used to fabricate studded fin tubes, it ensures high strength, corrosion resistance, and reliable performance in demanding conditions such as oil and gas, power generation, and refinery services.
Base Tube Material – ASME SA106 / ASTM A106 Grade B
ASME SA106 / ASTM A106 Grade B is a seamless carbon steel pipe specification for high-temperature service. It is widely used in power plants, refineries, petrochemical plants, and boiler applications where elevated temperatures and pressures are encountered. The seamless manufacturing process ensures a pipe with uniform composition and strength throughout its length.
Chemical Composition of SA106 Gr.B (per ASME SA106 / ASTM A106)
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.30 max |
| Manganese (Mn) | 0.29 – 1.06 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.035 max |
| Silicon (Si) | 0.10 min |
| Chromium (Cr) | 0.40 max |
| Copper (Cu) | 0.40 max |
| Molybdenum (Mo) | 0.15 max |
| Nickel (Ni) | 0.40 max |
| Vanadium (V) | 0.08 max |
Mechanical Properties of SA106 Gr.B (per ASME SA106 / ASTM A106)
| Property | Requirement |
|---|---|
| Tensile Strength, min | 415 MPa (60,000 psi) |
| Yield Strength, min | 240 MPa (35,000 psi) |
| Elongation in 50 mm (Longitudinal), min | 30% |
| Heat Treatment Temperature, min | 650°C (1200°F) |
Temperature and Pressure Tolerance
Operating Temperature Range: –29°C to 565°C, suitable for both low and high-temperature applications. Pressure Handling: Capable of withstanding high-pressure environments, making it ideal for boilers, heat exchangers, and fired heaters.
Studded Fin Tube – Design and Features
The studded fin design features radial or helical studs welded onto the outer surface of the base tube. This design significantly increases the heat transfer surface area, improving thermal efficiency in applications such as heat recovery systems, boilers, and fired heaters. The studs are attached through resistance welding techniques, ensuring minimal thermal distortion and strong, reliable bonds. Studded tubes are typically applied in the convection chamber of heating furnaces in the petrochemical industry to increase the heat transfer coefficient on the flue gas side. The surface area of studded tubes is two to three times that of bare tubes.
Manufacturing Process
The manufacturing of studded fin tubes involves the automated welding of studs onto the tube surface using electric resistance welding techniques. The welding process is controlled by PLC program, with feeding motors and graduation using servo motors to ensure precision and quality. Key steps include:
Tube Preparation – ASTM A106 Gr.B tubes are cleaned and inspected prior to finning
Stud Welding – Studs are automatically welded to the tube by electric resistance welding machine; welding parameters such as number of studs, pitch, and compensation coefficient are controlled by PLC
Quality Control – Welding precision is ensured through stepper motor control for stud division and linear guide for machine head slide
Base Tube Specifications for SA106 Gr.B Studded Fin Tube
| Parameter | Specification |
|---|---|
| Tube Material | Carbon Steel (SA106 Gr.B, SA53-B), Alloy Steel, Stainless Steel |
| Tube Outside Diameter | 20 mm to 219 mm (customizable) |
| Tube Wall Thickness | 2 mm to 16 mm |
| Tube Length | Up to 15,000 mm (customizable) |
| Bare Length (Unfinned Ends) | 50 mm / 50 mm (or as customer specified) |
Stud Specifications for SA106 Gr.B Studded Fin Tube
| Parameter | Specification |
|---|---|
| Stud Material | Carbon Steel, Stainless Steel, Alloy Steel |
| Stud Height | 5 mm to 35 mm (0.25" to 1.5") |
| Stud Diameter | 5 mm to 20 mm (standard 12.7 mm / 0.5") |
| Stud Pitch (Spacing) | 8 mm to 30 mm (standard 15.875 mm / 63 studs per meter) |
| Stud Shape | Cylindrical, Elliptical (customizable) |
Quality Control and Testing
Each studded fin tube undergoes inspection and testing in accordance with applicable standards and customer specifications:
Hydrostatic Test – Performed on base tube per ASME SA106 requirements
Non-Destructive Examination (NDE) – Ultrasonic Testing (UT), Eddy Current Testing (ET) as specified
Dimensional Inspection – Verification of tube OD, wall thickness, stud height, stud diameter, stud pitch, and overall length
Material Verification – Positive Material Identification (PMI) and full traceability to mill certificates
Visual Inspection – Surface finish, weld quality, and stud integrity
Welding Process Control – PLC-controlled welding parameters ensure consistent stud attachment quality
Typical Applications for ASME SA106 Gr.B Studded Fin Tube
Studded fin tubes are widely used in applications requiring high heat transfer efficiency in demanding environments:
Boilers – High-pressure boilers for power plants and industrial heating systems
Heat Exchangers – Petrochemical and chemical processing industries
Fired Heaters and Furnaces – Convection chamber heating in petrochemical industry
Economizers – Waste heat recovery in power plants
Superheaters – Power generation and steam systems
Air Preheaters – Coal-fired power plants and industrial heating
Waste Heat Recovery – Heat recovery steam generators (HRSG) and flue gas heat exchange
Air Coolers, Condensers, and Vaporizers
Studded tubes are particularly suited for applications where the surface is exposed to corrosive environments and where dirty gas streams require frequent or aggressive cleaning. They are a cost-effective choice for medium temperature and low corrosion waste heat recovery systems, especially for coal-fired power plants and petrochemical plants.
Advantages of ASME SA106 Gr.B Studded Fin Tubes
Enhanced Heat Transfer – The studded fins increase surface area by two to three times compared to bare tubes, improving thermal efficiency
High Strength and Durability – The base material's high tensile and yield strength ensure longevity even under cyclic thermal stresses
Corrosion Resistance – Carbon steel offers excellent resistance in various industrial environments
Cost-Effective – ASTM A106 Gr.B carbon steel offers excellent performance at a competitive price
High Thermal Conductivity – Carbon steel has high thermal conductivity, making it an efficient material for heat transfer applications
Easy Fabrication and Welding – Carbon steel is easy to fabricate and weld, allowing for customization to meet specific project requirements
Documentation
Each shipment is supplied with complete documentation including:
Mill Test Certificates (EN 10204 Type 3.1)
Heat treatment records
Dimensional inspection reports
Hydrostatic test reports
NDE reports (if applicable)
Welding procedure specifications (WPS) and procedure qualification records (PQR)
For a rapid quotation on ASME SA106 Gr.B Studded Fin Tube, please provide the following information:
Quantity (number of pieces or weight)
Base tube outside diameter, wall thickness, and length
Stud material, height, diameter, and pitch/spacing
Finned length and unfinned sections (bare ends)
End preparation (plain ends or beveled ends)
Delivery period required
