ASTM A312 TP304H Serrated Finned Tubes with 304H Fins Applied For Fired Heaters

ASTM A312 TP304H Serrated Finned Tubes with 304H Fins Applied For Fired Heaters

In simple terms, ASTM A312 TP304H Serrated finned tubes is a high-performance heat exchanger tube designed for extreme conditions. It's made of a special stainless steel pipe with fins on the outside that have a serrated (notched) edge to maximize heat transfer efficiency.

Here are some detailed breaksowns:

1. Base tube: ASTM A312 TP304H seamless tubes

(1). Chemical Composition

The composition is shown in percentage (%) by weight. The following are the required limits.

Note: The product analysis tolerance rules of ASTM A999 apply, meaning individual samples may vary slightly from these limits.

(2). Mechanical Properties

These are the minimum required properties for the finished pipe after final heat treatment (solution annealing).

2. Serrated Finned Tubes

The primary purpose of fins is to drastically increase the external surface area of the tube. This allows for much more efficient heat transfer from the hot gas or air outside the tube to the fluid (usually water or steam) inside the tube.

• Serrated Fins: This is a specific, high-performance design.The fins are not continuous solid strips. Instead, they have tiny, regular notches or serrations cut into their edges.
• Key Advantage: These serrations disrupt the boundary layer of gas flowing over the fins, creating turbulence. This turbulence significantly improves the heat transfer coefficient compared to solid (plain) fins. While they may cause a slightly higher pressure drop, the gain in heat transfer efficiency is substantial.

3. 304H Fins

This is important for compatibility and performance:

• Thermal Expansion: The tube and fins expand and contract at the same rate when heated and cooled, preventing stress and loosening at the bond.
• High-Temperature Strength: The fins themselves maintain their strength and oxidation resistance at high temperatures, preventing sagging, deformation, or degradation.
• Corrosion Resistance: Provides excellent resistance to the flue gases and external environment.

4.Key Characteristics & Advantages of ASTM A312 TP304H Serrated finned tubes with 304H fins

• Excellent High-Temperature Strength: The "H" grade of both tube and fins is the standout feature, making it suitable for superheaters and reheaters.
• Superior Heat Transfer Efficiency: The serrated fin design maximizes heat pickup from hot gases.
• Strong Metallurgical Bond: The HFW process ensures a permanent, low-resistance connection.
• Good Corrosion & Oxidation Resistance: Suitable for a wide range of flue gas environments.
• Durability: Resists thermal fatigue and mechanical damage.

Primary Application: Heat Recovery Steam Generators (HRSGs)

This is the most common and critical application. In combined cycle power plants, HRSGs capture waste heat from gas turbine exhaust to produce steam that drives a steam turbine, significantly increasing plant efficiency.

Within the HRSG, they are specifically used in the highest-temperature sections:

• Superheater: Heats saturated steam to a higher temperature ("superheated steam"), which dramatically improves the efficiency and power output of the steam turbine. This is a classic application for TP304H due to the high metal temperatures.
• Reheater: Takes steam that has already passed through the high-pressure section of the steam turbine, reheats it, and returns it to the intermediate/low-pressure section of the turbine. This also faces very high temperatures.

Application: Industrial & Utility Boilers

In large-scale coal, biomass, or waste-fired boilers, these tubes are used in similar high-heat-duty sections.

• Superheater and Reheater Sections: Just like in HRSGs, these are the sections of the boiler where steam temperatures are the highest, making TP304H the material of choice.
• Economizers (in corrosive environments): While often made of carbon steel, an economizer in a plant burning corrosive fuels (e.g., biomass with high chlorine content) might use 304H tubes for its superior corrosion resistance.

Application: Process Heaters & Fired Heaters

In refineries and petrochemical plants, fired heaters are used to heat process fluids to very high temperatures.

• Convection Section Tubes: The convection section, where hotter flue gases preheat the process fluid, often uses finned tubes to improve efficiency. When the process fluid or flue gas conditions are demanding (high temperature/corrosion), TP304H serrated finned tubes are specified.

Application: Waste Heat Boilers (WHBs)

• In various industrial processes (e.g., chemical production, metallurgy), waste heat boilers capture heat from process off-gases.