ASTM A312 TP304H Helical Serrated Fin Tube with 304H Fins For HRSG Evaporators

ASTM A312 TP304H Helical Serrated Fin Tube with 304H Fins For HRSG Evaporators

ASTM A312 TP304H Helical Serrated Fin Tube with 304H Fins for HRSG Evaporators is a specialized heat exchanger component used in Heat Recovery Steam Generators (HRSGs) —the systems that capture waste heat from gas turbine exhaust to produce steam for power generation or industrial processes.

In simple terms, it is a stainless steel tube wrapped with a toothed, spiral metal strip. Its job is to efficiently transfer heat from hot flue gases (on the outside) to water/steam (flowing inside the tube) inside the HRSG's evaporator section.

Unlike plain solid spiral fin tubes widely circulated on supplier catalogs, our segmented serrated fin profile cuts continuous boundary airflow layers when hot exhaust passes over fin surfaces. The slotted fin structure generates consistent micro-turbulence across the extended heat exchange surface, pushing overall heat transfer performance far higher than standard non-serrated alternatives without creating excessive flue gas pressure drop that burdens system blowers.

Breaking Down the Name

Key Design & Functional Features

Base Tube (TP304H): Handles high internal pressure and temperature, while resisting corrosion from steam/water and flue-gas condensates.

Helical Serrated Fins (304H):

• Increase the external surface area by 5–10 times compared to a bare tube.
• Improve the overall heat transfer coefficient by promoting turbulence on the gas side.
• The serrations make the fins self-cleaning to some extent—important in flue gases that may carry ash or particulates.

Firm Bond: The fins are attached via high-frequency resistance welding, creating a continuous metallurgical bond for reliable thermal conduction.

Core Material Advantages Targeted for HRSG Evaporator Service

1. Uniform 304H Stainless Steel Construction (Tube + Fins) TP304H features controlled elevated carbon content to deliver superior creep resistance and tensile stability under long-duration operating temperatures up to 600°C. Matching fin material eliminates differential thermal stress, a common failure point seen when dissimilar stainless grades are mismatched on conventional fin tube products. The alloy’s inherent oxidation and acid-flue-gas corrosion resistance drastically cuts maintenance downtime and extends evaporator service lifespan.

2. ASTM A312 Certified Seamless Base Tube Raw seamless tubing undergoes full third-party material certification with complete heat lot traceability, meeting ASME power boiler standards for pressure-bearing evaporator circuit operation. Wall thickness, outer diameter and straightness can be fully customized to match client HRSG module layout parameters.

Primary Application: Waste Heat Recovery & Power Generation

This is the core and most critical use of this product—capturing and utilizing waste heat from high-temperature industrial exhaust gases.

• Heat Recovery Steam Generators (HRSGs) – This is the dominant application. In combinedcycle gas turbine (CCGT) power plants, these finned tubes are installed inside the HRSG to recover heat from gas turbine exhaust (typically 500–600°C) and generate steam. This steam then drives a steam turbine, significantly boosting overall plant efficiency (often reaching 55–60%).
  • Key Locations: Within the HRSG, these tubes are most often placed in the highesttemperature sections, such as the superheater and reheater, where steam quality and temperature are maximized.
• Other Heat Recovery Equipment – They are also widely used in:
  • Waste Heat Boilers (e.g., in cement, glass, or steel plants)
  • Economizers (to preheat feedwater
  • Air Preheaters (to preheat combustion air)

All of these recover heat from process off-gases in chemical, metallurgical, and other heavy industries.

Other Important Industrial Applications

Beyond heat recovery, this finned tube serves other heavy industries that demand both hightemperature resistance and efficient heat exchange:

• Petrochemical & Refining Industry – Used in the convection sections of process fired heaters (furnaces) to heat crude oil or chemical feedstocks. Also found in various hightemperature reactors and shellandtube heat exchangers.
• Conventional Boilers & Power Plants – Apart from HRSGs, they are used in traditional fossilfuel power plant boilers, especially in superheater and reheater sections where steam temperatures exceed 540°C.