ASTM A213 T22 U Bend Alloy Steel HF Welding Solid Finned Tubes For Boiler Superheaters

ASTM A213 This specification covers seamless ferritic and aus-tenitic steel boiler, superheater, and heat-exchanger tubes, designated Grades T5,T9,T11,T22,TP304,TP316L, etc.

Chemical Composition (%)

Mechanical Properties

ASTM A213 T22 (2.25Cr-1Mo) U-bend high-frequency welded solid finned tube is a high-temperature, high-pressure, and corrosion-resistant heat exchange element. It combines the high-temperature creep strength of T22 alloy, the compact structure of the U-bend, and the high efficiency of high-frequency welded solid fins, enabling it to perform critical heat exchange tasks in harsh industrial environments, especially in petroleum refining and large power plant projects.

Compared to straight pipes, the U-shaped bend design not only saves 30-40% of space, but also alleviates thermal stress, as the U-shape absorbs the heat generated during expansion/contraction cycles. The U-shaped bend design also allows for more uniform flow between the inside and outside of the pipe, reducing uneven temperature distribution.

In short, ASTM A213 T22 U‑bend HF welded solid finned tubes are the optimal choice for high‑temperature, high‑pressure boiler superheaters, balancing performance, reliability, and cost.

Which Sections of Boiler Superheaters Adopt U-Bend Alloy Steel Finned Tubes

1. Final / Secondary Superheater (Core Application Zone):This area has the highest temperature and pressure within the boiler flue gas system.

Reasons for selecting U-shaped bent alloy steel finned tubes: The alloy base tube is resistant to high-temperature creep and corrosion; high-frequency welded integral fins significantly improve heat exchange efficiency;The U-shaped bend structure can release thermal expansion stress, preventing pipe cracking under high-temperature alternating conditions.

2.Screen-type superheater:it is located in the upper part of the furnace, in the transition zone between radiation and convection.

It withstands the dual effects of radiant heat transfer and high-speed flue gas scouring; it experiences severe thermal expansion and contraction and complex stress conditions; it employs U-shaped bent alloy finned tube bundles to achieve a compact arrangement, stress compensation, and enhanced heat transfer.

3.High-Temperature Deep Zone After Convection Superheater and Flue Gas

Deep within the convection shaft, the flue gas waste heat temperature is high; the heat load is concentrated, and the heat absorption is large; ordinary carbon steel cannot withstand the high tube wall temperature for extended periods; this area is equipped with U-shaped bent alloy steel finned tubes to enhance waste heat recovery capacity and prevent overheating failure.

Key Application

1.Power Generation (Thermal & Nuclear):

Supercritical/Subcritical Boiler Superheaters/Reheaters

Economizers & Air Preheaters

2.Petrochemical & Refining:

Ethylene Cracking Furnaces

Reformers & Hydrogen Plants

Hydrocracking/Hydrotreating Units

3.Waste Heat Recovery & Energy-from-Waste:

Waste Heat Recovery Boilers (WHRB)

Biomass/MSW Incineration Boilers

Cement/Steel Plant Waste Heat