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:

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)

(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

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.