ASTM A213 TP347H HFW Solid Finned Tube with 11-13Cr Fins For Superheaters
The ASTM A213 TP347H HFW Solid Finned Tube with 11-13% Cr Fins is a specialized high-performance heat exchanger tube designed for high-temperature and corrosive environments. Below is a detailed breakdown of its components and applications:
1. Base Tube: ASTM A213 TP347H
(1). Chemical Composition (ASTM A213 TP347H)
The composition meets ASTM A213 and ASME SA213 specifications. Key elements include:
| Element | Composition (% Weight) | Purpose |
| Chromium (Cr) | 17.0 – 20.0 | Corrosion/oxidation resistance |
| Nickel (Ni) | 9.0 – 13.0 | Austenite stability, high-temp strength |
| Carbon (C) | 0.04 – 0.10 | High-temperature creep resistance |
| Niobium (Nb) | 10×C – 1.0 | Stabilization (prevents carbide precipitation) |
| Manganese (Mn) | ≤ 2.0 | Improves hot workability |
| Silicon (Si) | ≤ 0.75 | Deoxidizer, strength at high temps |
| Phosphorus (P) | ≤ 0.045 | Impurity control |
| Sulfur (S) | ≤ 0.030 | Impurity control |
| Iron (Fe) | Balance | Base metal |
Notes:
"H" designation: Higher carbon (0.04–0.10%) for improved creep strength at elevated temps.
Niobium (Nb): Binds carbon to prevent chromium carbide formation (sensitization), enhancing weldability and corrosion resistance.
(2). Mechanical Properties (Room Temperature)
| Property | Value | Remarks |
| Tensile Strength | ≥ 515 MPa (75 ksi) | Minimum required |
| Yield Strength (0.2% offset) | ≥ 205 MPa (30 ksi) | Minimum required |
| Elongation (% in 50 mm) | ≥ 35% | Ductility indicator |
| Hardness (Brinell) | ≤ 192 HB | Typical annealed condition |
(3). High-Temperature Properties
TP347H is designed for service up to ~700°C (1292°F):
- Creep Strength: Excellent due to Nb stabilization and controlled carbon content.
- Oxidation Resistance: Forms a protective Cr₂O₃ layer at high temps.
- Thermal Expansion: Higher than ferritic steels (similar to other austenitics like 304H).
(4). Key Advantages of TP347H
✅ Nb stabilization reduces sensitization risk during welding.
✅ High creep strength at temps above 600°C.
✅ Good oxidation resistance in steam and flue gas environments.
2. Manufacturing Process: HFW (High-Frequency Welded)
HFW Tube: The base tube is made using High-Frequency Welding, a process that ensures a strong, consistent seam.
More cost-effective than seamless tubes but with comparable strength for many applications.
Suitable for high-pressure/temperature service if properly heat-treated.
3. Fins: Solid Fins with 11-13% Cr
- Fin Material: Typically a martensitic or ferritic stainless steel (e.g., AISI 409, 410, or similar).
- 11-13% Cr provides moderate heat and corrosion resistance while maintaining durability.
- Lower Cr than the base tube (TP347H) but sufficient for fin applications where mechanical strength is prioritized over extreme corrosion resistance.
- Fin Type: Solid fins (as opposed to serrated or embedded fins) offer:
- Better mechanical strength and heat transfer efficiency.
- Resistance to abrasion and oxidation in high-gas-flow environments.
4. Why This Combination?
- Base Tube (TP347H): Handles high temps/pressure + corrosion resistance.
- Fins (11-13% Cr): Provides cost-effective durability for extended surfaces exposed to flue gases/abrasion.
- HFW Process: Balances performance and affordability.
Comparison with Alternatives
| Feature | TP347H + 11-13Cr Fins | TP304H + Al Fins | Inconel 625 Finned Tubes |
| Max Temp | ~700°C | ~650°C | ~900°C |
| Corrosion Resistance | Excellent (base) / Moderate (fins) | Good | Outstanding |
| Cost | Moderate | Lower | Very High |
| Typical Use | Power plants, refineries | General heat exchangers | Extreme environments (e.g., chemical processing) |
Key Considerations
- Fin Bonding Method: Ensure fins are welded or tension-wrapped securely to avoid detachment under thermal cycling.
- Oxidation Resistance: 11-13% Cr fins may require protective coatings in highly oxidizing environments.
- Inspection: HFW tubes should be tested for seam integrity (e.g., hydrostatic, eddy current).
Conclusion
This tube is a cost-optimized solution for high-temperature heat transfer where the base tube handles harsh conditions while the fins provide durable, efficient heat exchange. For even harsher environments, higher-Cr/Ni fins or clad tubes might be used.
Primary Applications of ASTM A213 TP347H HFW Solid Finned Tube with 11-13% Cr Fins:
1. Power Generation (Coal, Gas, Waste Heat Recovery)
- Superheaters & Reheaters:
- The TP347H base tube withstands high-pressure steam (up to ~700°C) in boilers, while the 11-13% Cr fins resist oxidation from flue gases.
- Used in coal-fired plants and combined-cycle gas turbines (CCGT).
- Heat Recovery Steam Generators (HRSGs):
- Recovers waste heat from turbine exhaust gases, where fins enhance heat transfer efficiency.
2. Petrochemical & Refining
- Fired Heaters & Process Heat Exchangers:
- Resists sulfur-containing gases (e.g., in crude oil refining) due to TP347H’s corrosion resistance.
- Catalytic Reformer Units:
- Handles high temps (500–600°C) and corrosive hydrocarbon streams.
3. Waste Incineration & Biomass Plants
- Economizers & Air Heaters:
- The 11-13% Cr fins endure abrasive ash and acidic flue gases (e.g., from burning waste/biomass).
4. Chemical Processing
- Sulfuric/Nitric Acid Production:
- TP347H resists acidic condensation, while fins tolerate moderate corrosion.
5. Steel & Cement Industries
- Preheaters & Exhaust Gas Ducts:
- Fins withstand high-dust environments; base tube handles thermal cycling.
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ASTM A213 TP347H HFW Solid Finned Tube With 11-13Cr Fins For Superheaters Images
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