ASTM A335 P22 Studded Finned Tube with 13Cr Studs
for High-Temperature Radiant Sections & Waste Heat Recovery in Fired Heaters and Boilers

This studded finned tube is designed for continuous high-temperature and high-heat-flux service in the radiant sections of fired heaters, process heaters, and waste heat recovery boilers. The ASTM A335 P22 (2.25Cr-1Mo) seamless base tube provides excellent creep strength and structural integrity under elevated pressure and temperature, while the 13Cr (11-13% Chromium) studs deliver superior oxidation and sulfidation resistance on the gas side.

In petrochemical fired heaters and power-plant waste heat boilers, this combination solves three critical operational problems: rapid degradation of carbon-steel studs in high-temperature flue gas, insufficient heat absorption leading to tube overheating, and reduced service life caused by oxidation scaling and thermal fatigue.

ASTM A335 P22 Base Tube + 13Cr Stud Structure

The product consists of a seamless ASTM A335 P22 alloy steel base tube with solid 13Cr studs resistance-welded or arc-welded onto the external surface in a controlled density pattern (in-line or staggered).

The studs are attached by automated stud welding, creating a strong metallurgical bond that maintains integrity under thermal cycling and high heat flux. Unfinned (bare) ends are left as specified for welding or tube-sheet connection. The dense stud arrangement significantly increases the external heat-transfer surface area while remaining robust against abrasion and fouling.

Chemical Composition – ASTM A335 P22 Base Tube

Chemical Composition – 13Cr Studs (Typical)

Dimensional Tolerances – ASTM A335 P22 Studded Tube with 13Cr Studs

Performance Advantages in High-Temperature Service

• Excellent creep and rupture strength of ASTM A335 P22 base tube at elevated temperatures and pressures
• 13Cr studs provide significantly better oxidation and sulfidation resistance than carbon-steel studs in flue-gas environments
• High stud density increases external heat-transfer surface area by several times compared with bare tubes
• Strong metallurgical bond between stud and tube wall maintains heat conduction under thermal cycling
• Robust stud geometry resists abrasion, erosion, and mechanical damage better than thin fins
• Suitable for continuous operation in radiant and convection sections of fired heaters and waste heat boilers

Application Fields – ASTM A335 P22 + 13Cr Studded Finned Tube

• Radiant coils and process heaters in petrochemical and refining plants
• Waste heat recovery boilers (WHRB) and heat recovery steam generators (HRSG)
• Fired heater tubes in reformers and cracking furnaces
• High-temperature economizers and convection sections in power and industrial boilers
• Catalytic reformer and delayed coker heaters requiring oxidation-resistant extended surface

Packaging & Logistics

Finished studded tubes are cleaned, protected against corrosion, and packed in wooden cases or steel-frame crates with end protectors. Bundles are securely fastened to prevent movement during ocean transport.

Standard export packing is suitable for container shipment. Custom packing arrangements (including desiccant or additional protective wrapping) are available upon request.

Certificates & Quality Control

• Mill Test Certificates (EN 10204 3.1) for both base tube and stud material
• Dimensional inspection report covering tube and stud geometry
• Visual examination and weld integrity checks
• Optional non-destructive testing (PT, UT) and hydrostatic testing of the base tube
• Full material traceability from heat numbers to finished product

Commercial Terms

• MOQ: 500 meters or 1 metric ton (whichever is greater)
• Price Basis: FOB Shanghai / Ningbo / Tianjin
• Lead Time: 30–45 days after order confirmation and deposit (depending on quantity and specifications)
• Payment: T/T or L/C at sight