HFW U Bend Finned Tube ASME SA106 GR.B with Carbon Steel Fins For
Waste Heat Boiler
The A106 GR.B HFW U Bend Finned Tube refers to a specialized type
of heat exchanger tube with specific material, manufacturing, and
design characteristics.
Here's a breakdown of its components:
1. A106 GR.B
- Material Specification: ASTM A106 Grade B is a carbon steel pipe
standard for high-temperature service.
- Properties: Good strength, weldability, and resistance to oxidation
at elevated temperatures.
2. HFW (High-Frequency Welded)
- Manufacturing Process: The tube is formed from a steel strip and
welded using high-frequency induction or resistance welding,
ensuring a strong, consistent seam.
- Advantages: Cost-effective, good dimensional accuracy, and suitable
for moderate pressures/temperatures.
3. U Bend
- Design Feature: The tube is bent into a U-shape, allowing compact
heat exchanger designs (common in shell-and-tube heat exchangers).
- Purpose: Facilitates thermal expansion/contraction and simplifies
tube bundle assembly.
4. Finned Tube
- Enhanced Heat Transfer: Fins (either externally attached or
integrally formed) increase the surface area, improving heat
exchange efficiency.
- Applications: Used in air-cooled heat exchangers, boilers, or
economizers where gas-to-liquid heat transfer is needed.
Key Considerations
- Temperature/Pressure Limits: A106 GR.B is suitable for moderate
conditions (up to ~450°C).
- Fin Types: Could be helical, longitudinal, or serrated, depending
on the application.
- Bend Radius: Critical to avoid deformation; typically customized
per design requirements.
Chemical Composition of ASTM A106 Grade B (Weight %)
| Element | Composition (Max %) |
| 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 (≥ 0.10%) |
| Chromium (Cr) | 0.40% max (if specified) |
| Copper (Cu) | 0.40% max (if specified) |
| Molybdenum (Mo) | 0.15% max (if specified) |
| Vanadium (V) | 0.08% max (if specified) |
Notes:
A106 Gr. B is a carbon steel pipe with no significant alloying
elements.
Silicon must be ≥ 0.10% for deoxidation.
Residual elements (Cr, Cu, Mo, V) are limited if specified for
weldability.
Mechanical Properties of ASTM A106 Grade B
| Property | Value |
| Tensile Strength (min) | 415 MPa (60,200 psi) |
| Yield Strength (min) | 240 MPa (35,000 psi) |
| Elongation (min) | ≥ 30% (for 50mm gauge length) |
| Hardness (max) | 179 HB (Brinell) or 90 HRB (Rockwell B) |
Notes:
Elongation varies with wall thickness (thinner pipes may have
higher elongation).
Suitable for high-temperature service (up to 450°C / 840°F).
Commonly used in power plants, refineries, and boilers.
Comparison with Other Grades (A106 Gr. A & C)
| Grade | Tensile (MPa) | Yield (MPa) | Carbon (Max %) |
| A106 Gr. A | 330 min | 205 min | 0.25% |
| A106 Gr. B | 415 min | 240 min | 0.30% |
| A106 Gr. C | 485 min | 275 min | 0.35% |
Key Applications of A106 Gr. B Finned Tubes
1. Heat Exchangers & Boilers
- Shell-and-Tube Heat Exchangers:
The U-bend design allows thermal expansion/contraction, reducing
stress in fixed-tube setups
Fins enhance heat transfer between fluids (e.g., hot flue gas →
water/steam).
- Waste Heat Recovery Units (WHRU):
Captures waste heat from exhaust gases (e.g., in refineries,
chemical plants).
Preheats boiler feedwater using flue gas, improving energy
efficiency in power plants.
2. Power Generation
- Air-Cooled Condensers (ACC):
Finned tubes dissipate heat from steam to air (common in
dry-cooling power plants).
- Superheaters & Reheaters:
A106 Gr.B’s high-temperature resistance suits steam generation (up
to 450°C).
3. Petrochemical & Oil Refining
Transfers heat to hydrocarbons in cracking units or distillation
columns.
Uses finned tubes to heat crude oil before distillation, reducing
viscosity.
4. HVAC & Industrial Heating
Circulates hot oil through finned tubes for uniform heating in
industrial processes.
Finned tubes accelerate heat transfer in air dryers (e.g., paper,
food processing).
5. Renewable Energy Systems
Resists corrosion from flue gases while maximizing heat recovery.
Auxiliary heating with finned tubes ensures consistent energy
output.
