ASTM A335 P9 HFW Solid Finned Tube With CS Fins For Boilers and Economizers
ASTM A335 P9 HFW Solid Finned Tube with CS Fins refers to a specialized type of heat exchanger tube designed for high-temperature and high-pressure applications. Here's a breakdown of its components and features:
1. ASTM A335 P9
This is a standard specification for seamless ferritic alloy-steel pipes for high-temperature service.
(1). Chemical Composition of ASTM A335 P9 (Weight %)
| Element | Composition (%) |
| Carbon (C) | 0.15 max |
| Manganese (Mn) | 0.30 – 0.60 |
| Phosphorus (P) | 0.025 max |
| Sulfur (S) | 0.025 max |
| Silicon (Si) | 0.50 – 1.00 |
| Chromium (Cr) | 8.00 – 10.00 |
| Molybdenum (Mo) | 0.90 – 1.10 |
| Nickel (Ni) | 0.40 max (residual) |
| Vanadium (V) | 0.18 max (residual) |
Notes:
The alloy is 9% Cr-1% Mo, providing oxidation & creep resistance at high temperatures.
Low carbon content helps with weldability.
(2). Mechanical Properties of ASTM A335 P9
| Property | Value |
| Tensile Strength (min) | 415 MPa (60,000 psi) |
| Yield Strength (min) | 205 MPa (30,000 psi) |
| Elongation (min, %) | 30% (in 50 mm) |
| Hardness (max) | 179 HB (Brinell) / 90 HRB (Rockwell) |
| Allowable Stress (at 600°C / 1112°F) | ~30 MPa (varies by code) |
Notes:
Suitable for high-temperature service (up to ~600°C / 1112°F).
Good creep strength due to chromium-molybdenum content.
(3). Comparison with Other Grades (P11, P22, P91):
- P9 has higher Cr than P11 (1.25% Cr) but lower than P91 (9% Cr with V & Nb).
- Better oxidation resistance than carbon steel but less than stainless steels.
2. HFW (High-Frequency Welded)
- The tube is manufactured using High-Frequency Welding, a process that ensures a strong, consistent weld seam.
- HFW tubes are more cost-effective than seamless tubes while maintaining good mechanical properties.
3. Solid Finned Tube
- Fins are extended surfaces welded or attached to the tube to enhance heat transfer efficiency.
- Solid fins (as opposed to serrated or embedded fins) are continuous and robust, improving durability in harsh conditions.
4. CS (Carbon Steel) Fins
- The fins are made of carbon steel, which provides good thermal conductivity and mechanical strength
- Carbon steel fins are often used when corrosion resistance is less critical than cost and heat transfer efficiency.
5. Design Advantages:
- High-temperature strength (P9 material withstands up to ~600°C / 1112°F).
- Improved heat transfer due to finned design.
- Cost-effective compared to fully alloy-finned tubes.
Primary Applications of ASTM A335 P9 HFW Solid Finned Tube with CS Fins:
1. Power Plants & Boilers
- Superheaters & Reheaters – Withstands high steam temperatures (~600°C / 1112°F).
- Economizers – Recovers waste heat from flue gases.
- Heat Recovery Steam Generators (HRSG) – Used in combined-cycle power plants.
2. Petrochemical & Refineries
- Fired Heaters & Process Furnaces – Resists oxidation in high-temperature hydrocarbon environments.
- Catalytic Cracking Units – Handles corrosive gases and thermal cycling.
3. Chemical Processing
- Sulfur Recovery Units (Claus Process) – Resists acidic corrosion.
- Hydrogen Reformers – Operates under high-pressure hydrogen environments.
4. Waste Heat Recovery Systems
- Exhaust Gas Boilers – Recovers heat from industrial exhaust streams (e.g., cement, steel plants).
- Air Preheaters – Preheats combustion air to improve boiler efficiency.
5. District Heating & HVAC Systems
- High-Temperature Hot Water (HTHW) Systems – Used in large-scale heating networks.
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ASTM A335 P9 HFW Solid Finned Tube With CS Fins For Boilers Economizers Images
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