EN10217-7 1.4301 Extrudded Finned Tube with Al1060 Fins for HRSGs System
EN10217-7 1.4301 Extrudded Finned Tube with Al1060 Fins for HRSGs System
EN10217-7 1.4301 Extruded Finned Tube with Al1060 Fins is a high-performance, pressure-rated heat exchanger tube where:
- The inner pressure-bearing tube is made of stainless steel AISI 304 (1.4301), manufactured and tested according to the strict pressure vessel tube standard EN 10217-7. This makes it suitable for steam, hot water, or other process fluids under pressure.
- The outer heat transfer fins are made of high-conductivity, commercially pure aluminum (Al1060).
- The fins are extruded from a sleeve, creating a durable, monolithic finned structure with no gaps or weak joints.
Here are some detailed breakdowns:
1. Base Tube:
(1) EN 10217-7 1.4301 (AISI 304) – Chemical Composition
The composition is specified for the steel product (tube). Values are maximum percentages unless a range is given.
| Element | Standard Range / Max (%) | Typical Value / Notes |
| Carbon (C) | ≤ 0.07% | Low carbon for improved weldability and corrosion resistance. |
| Silicon (Si) | ≤ 1.00% | Typically around 0.3-0.6%. |
| Manganese (Mn) | ≤ 2.00% | Typically around 1.0-1.5%. |
| Phosphorus (P) | ≤ 0.045% | Impurity, kept low. |
| Sulfur (S) | ≤ 0.015% | Impurity, kept very low for weldability. |
| Chromium (Cr) | 17.5 - 19.5% | Primary corrosion-resistant element. |
| Nickel (Ni) | 8.0 - 10.5% | Stabilizes the austenitic structure, adds toughness. |
| Nitrogen (N) | ≤ 0.11% | Typically specified max. |
| Iron (Fe) | Balance | Remaining composition. |
Key Point: The 1.4301 grade is synonymous with AISI 304. For seamless/welded pressure tubes under EN 10217-7, the specific limits above are mandated to ensure consistent performance.
(2) EN 10217-7 1.4301 (AISI 304) – Mechanical Properties
Properties are specified for the finished tube in the delivery condition (typically annealed). The standard defines minimum requirements.
| Property | Requirement (EN 10217-7) | Typical Value (Annealed) |
| Yield Strength (Rp0.2) | ≥ 210 MPa | ~250 - 300 MPa |
| Tensile Strength (Rm) | 500 - 700 MPa | ~540 - 600 MPa |
| Elongation at Fracture (A) | ≥ 35% (on 5.65√S₀) | ~45 - 55% |
| Hardness (HV10) | Not typically specified in EN 10217-7, but common for material check. | ~150 - 180 HV |
| Proof Test Pressure | As per standard calculation (based on dimensions & SMYS). | Applied during manufacturing per EN 10217-7 requirements. |
| Non-Destructive Testing (NDT) | Mandatory. Each tube must be tested (e.g., eddy current). | Ensures absence of harmful defects. |
2. Fins: Al1060 Extruded Fin
"Extruded" Process: A specialized machine uses tremendous pressure to roll or extrude the aluminum sleeve, forcing the aluminum to flow and form a tight, continuous helical fin from the aluminum itself. This creates a strong, integral, metallurgical bond between the fin and the tube with excellent heat transfer characteristics.
Al1060: This is a designation for commercially pure aluminum (at least 99.6% aluminum).
Key Properties:
- Excellent Thermal Conductivity: Aluminum is chosen primarily for this reason—it transfers heat from the base tube to the fin surface very efficiently.
- Good Corrosion Resistance: Forms a protective oxide layer.
- High Formability/Malleability: Essential for the extrusion process.
- Lightweight & Cost-Effective: Compared to making the fins from stainless steel.
3. Key Advantages of This Specific Combination:
- Corrosion Resistance (Internal): The 1.4301 tube resists corrosion from the internal fluid.
- Pressure Integrity: The tube meets a recognized pressure equipment standard.
- High Efficiency: The aluminum fins provide outstanding heat dissipation.
- Robust Bond: The extruded fin ensures long-term thermal performance without loosening.
- Cost Optimization: Using expensive stainless steel only where needed (for pressure/corrosion) and cheaper, more conductive aluminum for the fins.
Core Application Principle
This tube is designed for industrial heat exchangers where a pressurized fluid (liquid or gas) inside the tube needs to reject heat to ambient air (or another gas/air stream) flowing over the fins.
By Industry & Application
1. Power Generation
- Heat Recovery Steam Generators (HRSGs): Capturing exhaust heat from gas turbines to produce steam for a secondary steam turbine. These tubes often form the evaporator or economizer sections.
- Air-Cooled Condensers (ACCs): Condensing exhaust steam from a turbine in power plants located in water-scarce regions. The 1.4301 tube handles the steam/condensate, while Al fins maximize heat rejection to air.
- Feedwater Heaters & Deaerators: Pre-heating boiler feedwater using extracted steam. The pressure rating (EN10217-7) is critical here.
2. Oil, Gas & Petrochemical
- Process Fluid Coolers (Fin-Fan Coolers / Air Coolers): Cooling process streams (hydrocarbons, water, etc.) after distillation, cracking, or other reactions. The 1.4301 (304 SS) resists corrosion from many process chemicals and cooling water.
- Gas Compression Aftercoolers: Cooling hot compressed gases (e.g., natural gas) before they enter pipelines or next stages.
- Lube Oil & Seal Oil Coolers: Maintaining optimal oil temperature for large rotating equipment like turbines and compressors.
3. HVAC-R (Large Scale Industrial)
- Industrial Chiller Condensers: Rejecting heat from refrigerant to atmosphere.
- Heat Pump Coils: For large commercial or district heating/cooling systems.
- Thermal Storage Systems: As part of heat exchangers for large-scale energy storage.
4. Marine & Offshore
- Central Cooling Water Coolers: Using ambient air to cool the central fresh water loop that cools shipboard engines and equipment. The 1.4301 offers good resistance to marine atmospheres.
- LNG Heat Exchangers: In auxiliary systems for liquefied natural gas facilities.
5. General Industrial
- Waste Heat Recovery Units: Capturing and reusing heat from furnace exhausts, ovens, or dryers.
- Hydraulic Oil Coolers: For heavy machinery in steel mills, plastic injection molding, etc.
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