ASTM A249 TP304L L Type Finned Tube With AL1060 Fins For Waste Heat
Recovery Units
ASTM A249 TP304L L-Type Finned Tube with AL1060 Fins is a
specialized heat exchanger component designed for efficient heat
transfer in various industrial applications. Here's a detailed
breakdown:
1. Base Tube: ASTM A249 TP304L
Material: Stainless Steel 304L (low carbon variant, ≤0.03% carbon).
Standard: ASTM A249 specifies seamless and welded austenitic steel
tubes for boilers, heat exchangers, and condensers.
(1). Chemical Composition (Weight %)
The composition complies with ASTM A249/A249M and ASTM A312/A312M
(for seamless/welded pipes).
| Element | TP316L Requirements (%) | Typical Values (%) |
| Carbon (C) | ≤ 0.035 (max) | 0.02 – 0.03 |
| Manganese (Mn) | ≤ 2.00 (max) | 1.00 – 1.50 |
| Silicon (Si) | ≤ 1.00 (max) | 0.30 – 0.60 |
| Phosphorus (P) | ≤ 0.045 (max) | 0.020 – 0.040 |
| Sulfur (S) | ≤ 0.030 (max) | 0.010 – 0.020 |
| Chromium (Cr) | 16.0 – 18.0 | 16.5 – 17.5 |
| Nickel (Ni) | 10.0 – 14.0 | 10.5 – 12.5 |
| Molybdenum (Mo) | 2.0 – 3.0 | 2.2 – 2.8 |
| Nitrogen (N) | ≤ 0.10 (max) | 0.02 – 0.06 |
| Iron (Fe) | Balance | ~65 – 70 |
Key Notes:
Low Carbon (≤0.035%): Reduces carbide precipitation during welding,
improving corrosion resistance in welded structures (hence "L"
grade).
Molybdenum (2-3%): Enhances resistance to pitting and crevice
corrosion, especially in chloride environments (e.g., seawater,
chemical processing).
(2). Mechanical Properties (ASTM A249)
| Property | Requirements | Typical Values |
| Tensile Strength (MPa) | ≥ 485 | 500 – 620 |
| Yield Strength (MPa) | ≥ 170 | 200 – 300 |
| Elongation (% in 50mm) | ≥ 35 (for welded) | 40 – 50 |
| ≥ 40 (for seamless) | |
| Hardness (Rockwell B) | ≤ 95 HRB (max) | 70 – 90 HRB |
Additional Notes:
Heat Treatment: Solution annealed at 1010–1120°C (1850–2050°F)
followed by rapid cooling (quenching) to maintain corrosion
resistance.
Impact Toughness: Excellent at cryogenic temperatures due to
austenitic structure.
Weldability: Excellent (no post-weld heat treatment required).
2. L-Type Finned Tube
Fin Type: "L-Type" refers to fins that are embedded or wound into a groove on the
tube's outer surface, ensuring strong mechanical bonding.
Advantages:
- Enhanced heat transfer efficiency due to increased surface area.
- Robust fin-to-tube contact, reducing thermal resistance.
3. AL1060 Fins
Material: Aluminum 1060 (99.6% pure aluminum).
Properties:
- High thermal conductivity (~235 W/m·K), ideal for heat dissipation.
- Lightweight, corrosion-resistant, and cost-effective.
- Soft and malleable, making it easy to form into fins.
4. Key Features or Benifits
✅ Corrosion Resistance: TP304L (internal) + AL1060 (external) combo
suits harsh environments.
✅ Thermal Efficiency: Aluminum fins (235 W/m·K) enhance heat
transfer vs. steel fins.
✅ Cost-Effective: Cheaper than all-stainless-steel finned tubes
while maintaining performance.
✅ Durable Bonding: L-Type fins resist vibration/thermal expansion
loosening.
5. Why This Combination?
Cost-Effectiveness: Aluminum fins are cheaper than stainless steel
while providing superior thermal performance.
Durability: TP304L resists oxidation and pitting, while AL1060
forms a protective oxide layer.
The ASTM A249 TP304L L-Type Finned Tube with AL1060 Fins is a
high-efficiency heat transfer component widely used in industries
where corrosion resistance, thermal performance, and durability are
critical. Below are its key applications:
1. Air-Cooled Heat Exchangers (ACHEs)
- Power Plants: Cooling steam condensers, turbine exhausts, and
auxiliary systems.
- Oil & Gas: Cooling process fluids (e.g., hydrocarbons, natural gas)
in refineries and petrochemical plants.
- HVAC Systems: Used in large industrial chillers and air handlers.
2. Waste Heat Recovery Systems
- Cement & Steel Plants: Recovers heat from exhaust gases to preheat
combustion air.
- Chemical Processing: Recovers energy from hot flue gases or process
streams.
3. Refrigeration & Condensers
- Ammonia/CO₂ Refrigeration: Used in cold storage, food processing,
and industrial cooling.
- Evaporative Condensers: Enhances heat rejection in cooling towers.
4. Industrial Boilers & Economizers
- Heat Recovery Steam Generators (HRSGs): Recovers waste heat from
gas turbines.
- Boiler Exhaust Gas Cooling: Lowers flue gas temperatures before
emission treatment.
5. Marine & Offshore Applications
- Seawater Cooling Systems: Used in ship engines and offshore
platforms.
- Desalination Plants: Preheats feedwater in multi-stage flash (MSF)
or MED systems.
6. Renewable Energy Systems
- Geothermal Power Plants: Transfers heat from geothermal brine.
- Biomass Boilers: Recovers heat from combustion gases.
