ASTM A106 Gr.B Studded Tubes Finned Tubes For Convection Sections of Fired Heaters

ASTM A106 Gr.B Studded Tubes Finned Tubes For Convection Sections of Fired Heaters

ASTM A106 / ASME SA106 Grade B seamless carbon steel pipe serves as the "workhorse" material for high-temperature, pressure-bearing applications in the refining and petrochemical industries. Its selection is driven not merely by cost considerations, but by several critical factors:

Exceptional high-temperature performance.A106 Grade B steel maintains stable mechanical properties in high-temperature operating environments, such as those found in process furnaces. It retains reliable creep resistance and high-temperature strength under conditions where the performance of standard carbon steel would otherwise degrade.
The pipes are manufactured using a seamless process (entirely free of welds), ensuring the absence of longitudinal seams—which are typically the weakest points in components subjected to thermal cycling.
Consistent quality and full traceability. The chemical composition and mechanical properties of the material are strictly controlled. Every heat of steel is traceable and certified, with comprehensive documentation available in accordance with EN 10204 3.1/3.2 standards, meeting project-specific requirements for end-to-end traceability.
As the primary load-bearing component, the base pipe withstands internal pressure and process temperatures, while external systems—such as fins or studs—facilitate heat transfer. A robust foundation of this nature is essential for ensuring that enhanced heat-transfer surfaces continue to deliver value throughout the entire service life of a process furnace.

Chemical Composition (%)

Mechanical Properties

Advantages of Studded Tubes in Convection Sections of Fired Heaters

In the convection section, the high-temperature flue gas exiting the radiant section carries a significant portion of the recoverable heat from the process heater. However, because flue gas has poor thermal conductivity and moves at a relatively low velocity, it tends to form a "stagnant boundary layer" along the tube walls, which acts as an insulating barrier. Plain tubes (tubes without fins or studs) are ineffective at capturing this thermal energy.

Studded tubes (or pin tubes) feature multiple rows of robust studs welded onto the outer surface—typically applied individually via resistance welding—which increases the surface area to approximately 2–3 times that of a plain tube. Furthermore, these studs disrupt the boundary layer, thereby enhancing the convective heat transfer coefficient. This design is well-suited for environments involving dust-laden, fouling-prone, or corrosive gases, as well as temperatures exceeding approximately 450°C—conditions commonly encountered in process heaters fired by fuel oil or heavy residual oil.

Application 

Convection sections of fired heaters — crude heaters, reformers, coker and cracking furnaces, recovering heat from flue gas before stack discharge

Waste-heat boilers and economisers — downstream of gas turbines, incinerators and process furnaces

CFB and biomass boilers — where abrasive bed material would erode unprotected tubes

Waste-to-energy plants — resisting chloride- and ash-laden flue gas in water walls and superheaters

Available Sepecification Max Operating Temperature 500℃