ASTM A213 TP347H HFW Finned Tube with Carbon Steel Solid Fins For Fired Heaters

ASTM A213 TP347H HFW Finned Tube with Carbon Steel Solid Fins For Fired Heaters

An ASTM A213 TP347H HFW Solid Finned Tube with Carbon Steel Fins is a high-performance heat exchanger tube. It's essentially a core tube made of a special, heat-resistant stainless steel, to which carbon steel fins are permanently bonded to increase its surface area. This design drastically improves heat transfer efficiency in high-temperature and high-pressure environments, like those found in boilers and heaters. It uses a high-temperature stainless steel tube (TP347H) for strength and corrosion resistance in the primary fluid stream, and cost-effective carbon steel fins to maximize heat exchange with the secondary fluid (usually air or gas).

Please see the below detailed breakdowns:

1. Base Tube: ASTM A213 TP347H seamless tube

(1). Chemical Composition (Weight %)

The composition is critical for achieving the desired corrosion resistance and high-temperature strength. The "H" grade has stricter controls on carbon content.

Note on Niobium (Nb): The minimum Niobium content is calculated as 8 times the Carbon content, but not less than 0.40%. This ensures there is enough Niobium to fully combine with the Carbon, preventing the formation of chromium carbides.

(2). Mechanical Properties

These properties are typically measured at room temperature on a sample of the finished tube.

Important Note on High-Temperature Properties: The primary reason for using the "H" grade is its guaranteed elevated temperature performance (specified in ASTM A213). While room-temperature properties are listed above, the tube is designed for service where creep strength (resistance to deformation under stress at high temperatures over time) is the critical factor. This performance is verified through mandatory high-temperature testing.

2. Fin Type: HFW Solid Fins in Carbon Steel

It means the tube starts as a strip of steel (skelp) that is rolled into a cylindrical shape and then the seam is welded using a high-frequency electric current. This process is efficient and produces a high-quality weld. For this application, the weld is typically heat-treated to ensure its properties match the base metal.

Why use a different material? Carbon steel is chosen because it is:

• Cost-Effective: Significantly cheaper than stainless steel.
• Good Thermal Conductor: It has higher thermal conductivity than stainless steel, which helps transfer heat efficiently.
• Adequate for the Environment: The fins operate at a lower temperature than the core tube and are often in a less corrosive environment (e.g., hot air or flue gas). Using carbon steel keeps the overall product cost down without compromising performance.

3. Key Characteristics of ASTM A213 TP347H HFW Solid Finned Tube with Carbon Steel Fins

• High-Temperature Strength: The TP347H core tube can withstand extreme pressures and temperatures.
• Corrosion/Oxidation Resistance: The stainless steel core resists oxidation and corrosive flue gases.
• Excellent Heat Transfer: The carbon steel fins maximize heat dissipation or absorption.
• Cost-Effective Design: The combination of a high-performance core with economical fins optimizes value.

Primary Application: Heat Recovery Steam Generators (HRSGs)

This is the most classic and widespread application for this exact tube specification. HRSGs are the large boilers attached to gas turbines in combined cycle power plants. They capture ("recover") waste heat from the turbine's hot exhaust to produce steam, which then drives a steam turbine for additional electricity generation.

Within the HRSG, this finned tube is typically used in the Superheater and sometimes the Evaporator sections.

Other Key Applications:

1. Process Heaters (Fired Heaters) in Refineries & Petrochemical Plants:

These are large furnaces that heat process fluids (e.g., crude oil, hydrocarbons) to very high temperatures.

The finned tubes are used in the convection section of the heater, where heat is recovered from the flue gas before it goes to the stack.

The TP347H tube handles the high-pressure, high-temperature hydrocarbon fluid inside, while the carbon steel fins efficiently absorb heat from the combustion flue gas.

2. Waste Heat Boilers (WHBs) in Chemical and Industrial Processes:

Similar to HRSGs, these units capture heat from industrial process streams (e.g., chemical reactor effluent, furnace off-gas) that would otherwise be wasted.

The specific material (TP347H) is selected when the process gas being cooled is sufficiently hot and/or corrosive to require a high-grade stainless steel for the tube.

3. Superheaters in Industrial Boilers:

Any industrial boiler system that requires superheated steam (saturated steam heated to a higher temperature) for process use or power generation might use these tubes in the superheater section if the temperature and pressure ratings demand it.