Base Tube Material: ASTM A179

Type: Seamless cold-drawn low-carbon steel tubes.

Excellent thermal conductivity (good for heat transfer).

Good corrosion resistance in boiler feedwater and steam condensate environments.

Smooth internal bore (minimizes pressure drop and fouling).

High pressure and temperature capability.

Relatively cost-effective compared to alloy steels.

Typical Applications: Ideal for tubesheets in shell-and-tube heat exchangers handling water, steam, and condensate.

Fin Type: Embedded (G-Fin)

Manufacturing Process: A strip of fin material (usually carbon steel or sometimes stainless steel for corrosion resistance) is fed into a precision machine. The machine uses hardened steel wheels or tools to simultaneously cut a helical groove into the base tube wall and physically deform the fin strip into this groove under high pressure. The fin base becomes mechanically locked ("embedded") into the groove.

Key Characteristics (G-Type specifically):

• Strong Mechanical Bond: The fin is physically anchored into the base tube metal, creating a robust, integral connection. This is crucial for thermal performance and durability under thermal cycling and vibration.
• Excellent Heat Transfer: The embedded fin creates a continuous, uninterrupted metal path from the base tube to the fin tip. This minimizes contact resistance, maximizing heat transfer efficiency. The bond is often metallurgically tight enough to approach the efficiency of an extruded fin.
• Good Contact Ratio: The groove ensures a large surface area contact between the fin base and the tube wall.
• Durability: Highly resistant to fin loosening ("lifting") due to thermal cycling or handling.
• Fin Geometry: Typically produces helical fins with a rectangular or near-rectangular cross-section. The "G" designation often implies a specific profile or groove depth/width ratio optimized by a particular manufacturer or standard practice. Fins per inch (FPI) and fin height can be customized.
• Base Tube Integrity: While material is displaced to form the groove, the process is carefully controlled to maintain the base tube's pressure integrity. The groove depth is a significant percentage of the wall thickness.

Advantages of A179 Embedded G-Type Fin Tubes:

• High Thermal Efficiency: Excellent bond minimizes thermal resistance.
• Robust & Reliable: Strong mechanical bond withstands thermal stress, vibration, and cleaning.
• Good Corrosion Resistance (Base Tube): Suitable for common boiler/heat recovery applications.
• High Pressure Capability: Seamless A179 base tube combined with the controlled groove depth maintains pressure integrity.
• Customizable: Fin height, thickness, and FPI can be tailored to the application.
• Suitable for Dirty Gases: The robust fin attachment resists damage from soot blowing or mechanical cleaning better than some welded fins.

Typical Applications:

1. Heat Recovery Steam Generators (HRSGs): Economizers and evaporator sections.
2. Boilers (Firetube & Watertube): Economizers and air heaters.
3. Process Heaters & Air Heaters: Where efficient gas-to-liquid heat transfer is needed.
4. Exhaust Gas Heat Recovery Systems.

In Summary:

An A179 Embedded G-Type Fin Tube combines a seamless low-carbon steel base tube (ASTM A179), chosen for its thermal conductivity, pressure capability, and water/steam corrosion resistance, with high-performance helical fins mechanically locked into grooves machined into the tube wall. The "Embedded G" process creates an exceptionally strong bond, resulting in highly efficient and durable heat transfer, making it a premium choice for demanding applications like heat recovery boilers and economizers. The "G-Type" refers to the specific profile and method of the embedded fin groove.