ASTM A106 Gr B High Frequency Welded Fin Tube For Air Cooler Heat Exchanger

Base Pipe Material Strength (ASTM A106 Gr.B):

• Minimum Yield Strength (YS): 240 MPa (35,000 psi)
• Minimum Tensile Strength (TS): 415 MPa (60,000 psi)
• These values are the absolute minimums required by the ASTM A106 standard. Actual tested values from the pipe mill are typically 10-20% higher.
• Material: Carbon steel (C-Mn) with controlled chemistry for strength and weldability at elevated temperatures.

A106 Gr.B HFW Fin Tube Application

• Heat Recovery Steam Generators (HRSGs)

• Boilers (Economizers, Air Heaters)

• Process Heaters & Furnaces (Convection Sections)

• Air Coolers & Heat Exchangers for high-temp/pressure fluids

• Thermal Oil Heaters

A106 Gr.B HFW Fin Tube Strength

1. Base Tube Distortion: Applying fins (especially via embedded/G-fin or welded methods) involves significant mechanical force or localized heating. Reputable manufacturers carefully control processes to minimize distortion, ovality, or wall thinning of the base A106 Gr.B HFW tube.
2. Localized Annealing (Welded Fins): If fins are attached via resistance welding (L-foot, LL-foot), the localized heat input can cause slight annealing (softening) in tiny spots directly under the welds. This does not significantly reduce the overall longitudinal strength of the tube. The primary concern is the integrity of the fin bond, not base tube strength degradation.
3. Residual Stresses: Both mechanical finning (embedded) and thermal finning (welded) can introduce localized residual stresses. Good manufacturing practice aims to minimize these.
4. Fin Strength ≠ Tube Strength: The fins themselves (typically aluminum or steel) contribute negligibly to the pressure-containing strength of the assembly. Their function is purely thermal enhancement. The pressure-retaining capability relies entirely on the strength of the A106 Gr.B HFW base tube.

ASTM A106 Gr.B High Frequency Welding Fin Tube For Air Cooler Heat Exchanger

• "A106 HFW" Nuance: While the base material meets A106 Gr.B specs, strictly speaking, the ASTM A106 standard itself covers only seamless pipe. Tubes meeting A106 Gr.B chemistry/mechanics but made via HFW are often specified as "A106 Gr.B HFW" or "ERW" to be precise. They might also fall under other welded pipe specs like ASTM A672 (which is commonly used for welded boiler tubes) but with chemistry matching A106 Gr.B.
• Fin Specification: The description doesn't specify the fin type (e.g., embedded, welded), fin material (e.g., Al, steel), fin height, fin density (fins per inch), or fin thickness. These are critical design parameters for the specific heat transfer application.
• Temperature Limits: Ensure the maximum operating temperature of the finned tube assembly (considering base tube, fins, and attachment method) is suitable for the application, staying within A106 Gr.B limits and fin material/attachment limits.