Carbon Steel A106 GR.B Spiral Finned Tube For Reheater and Economizer

1. A106 Gr.B Spiral Finned Tube working principle

• High temperature stability: It can operate at 425℃ for extended periods and can withstand short-term exposure to 565℃.
• High thermal conductivity: The thermal conductivity of carbon steel substrate is about 50 W/m·K, and the heat transfer efficiency is improved by 3–8 times after combining with fins.
• High pressure resistance: Seamless structure + thick-walled design (such as SCH80) with a pressure-bearing capacity of over 20 MPa.
• Process compatibility: Supports secondary processes such as bending (3D–10D curvature) and welding (requiring controlled carbon equivalent CE≤0.5%).

2. A106 Gr.B Spiral Finned Tube Characteristics and working principle

Finned tubes efficiently transfer the heat of fluids (such as steam, flue gas, etc.) to the external environment (such as air) or another fluid by expanding the heat transfer surface area. For example:

• Boiler economizer: flue gas → finned tube → heating feedwater.
• Air cooler: High-temperature fluid inside the tube → heat dissipation through fins → air cooling.

3. A106 Gr.B Spiral Finned Tube Applications

• Energy and Power: Economizer and superheater pipelines of utility boiler. The secondary water supply system of the nuclear power plant (attention should be paid to FAC corrosion control).
• petrochemical industry: Heat exchanger, condenser, and reactor heating coil.
• Industrial manufacturing: Waste heat recovery system (such as waste heat utilization of flue gas in steel plants). Drying equipment, industrial kiln heat exchange module.

4. A106 Gr.B Spiral Finned Tube Advantages

• Economics: The cost is lower than that of stainless steel, offering high cost-effectiveness throughout its lifecycle.
• Mature technology: Good consistency in mass production of seamless tubes, and mature fin processing technology.
• Easy maintenance: convenient welding repair (requires preheating to 150℃ to prevent cracking).

5. A106 Gr.B Spiral Finned Tube Frequently Asked Questions (FAQ)
Q: What is the maximum operating temperature for ASTM A106 Gr.B finned tubes?
A: For long-term service, the temperature should not exceed 425℃, while for short-term service (such as start-stop), it can reach up to 565℃.
Q: Is it suitable for corrosive media?
A: It is suitable for use in weakly corrosive environments; in strong acid/alkali or high-velocity (>15 m/s) media, it is recommended to use low-alloy steel containing Cr (such as A672 Gr.B60).
Q: What special precautions should be taken during welding?
A: Control the carbon equivalent (CE=%C+%Mn/6+...≤0.5%), preheat to 150–200℃ before welding, and slow down the cooling after welding.
Q: How to detect quality defects of finned tubes?
A: The mandatory inspection items include hydrostatic testing (or non-destructive testing UT/ET), wall thickness tolerance (≥ 87.5% of the nominal value), and chemical composition retesting.
Q: What is the correspondence with domestic materials?
A: There is no direct equivalent grade, but the mechanical properties are close to those of 20# steel in GB 8163 (note that 20# steel has weaker high-temperature properties).