ASTM A335 P11 Alloy Steel Serrated Finned Tubes for Heat Recovery Steam Generator

ASTM A335 P11 Alloy Steel Serrated Finned Tubes for Heat Recovery Steam Generator

Chemical Composition (%) Maximum

Mechanical Properties

ASTM A335 P11 seamless Cr‑Mo alloy steel  pipes designed for high temperatures,high pressure service.P11 exhibits continuous creep and oxidation resistance at temperatures up to 550–570°C, and good thermal cycling stability. P11 also demonstrates excellent resistance to sulfides and high-temperature hydrogen corrosion.

Serrated fin characteristics:

Helical serrated fins breaks the gas boundary layer, increasing heat transfer coefficient by 10%~40% compared to smooth solid fins.Self-cleaning turbulence reduces ash/dust buildup in flue gas conditions.Balanced thermal area and acceptable gas-side pressure drop, suitable for large convection jets.

Core Advantages of Alloy Steel Serrated Finned Tubes for Heat Recovery Steam Generator

1. ASTM A335 P11 base tubes possess superior high-temperature and high-pressure performance:

The material composition (1.25Cr-0.5Mo seamless alloy steel) conforms to ASME SA-335 standards and is specifically designed for continuous high-temperature steam operation within HRSG tubes, with long-term operating temperatures reaching 550–570°C.

It exhibits excellent creep resistance and thermal fatigue resistance, resisting deformation, cracking, and wall thinning under frequent gas turbine load fluctuations and typical start-stop thermal cycles of combined cycle HRSGs.

Excellent resistance to hydrogen corrosion and sulfide corrosion effectively resists trace sulfides and steam oxidation from turbine exhaust gas, extending service life in flue gas recovery environments.

Maintaining stable mechanical strength under high operating pressures: Matching the design of the HRSG's high-pressure evaporator, superheater, and reheater circuits, eliminating the risk of pressure leakage.

2. Superior Heat Transfer Performance from Serrated Fin Structure:

The serrated cuts break up the stagnant thermal boundary layer on the fin surface, increasing the flue gas heat transfer coefficient by 20%–40% compared to solid smooth finned tubes.

Its compact waste heat boiler layout, with a higher heat exchange area per unit length, reduces the overall footprint of the convection tube, thereby lowering investment and space requirements for power plant skid-mounted equipment.

Excellent anti-fouling and self-cleaning effects: Turbulent flue gas continuously washes the fin surface, inhibiting the adhesion of ash, dust, and condensate from the turbine exhaust, reducing scaling thermal resistance, and maintaining stable waste heat recovery efficiency over the long term.

3. Comprehensive Operational and Economic Advantages of Waste Heat Boiler Systems:

Can maximize the capture of waste heat from high-temperature gas turbine exhaust, increasing steam output and power generation capacity without additional fuel input.

The dual advantages of the P11 alloy's corrosion resistance and the anti-fouling properties of the serrated fins minimize downtime for cleaning and tube replacement, thereby reducing power plant operating and maintenance costs.

The excellent metallurgical bond between the fins and the base tube, achieved through high-frequency resistance welding, results in a tight connection with negligible contact thermal resistance, preventing fin peeling or detachment under the thermal shock and vibration of the waste heat boiler.

Suitable for all core convection sections of the waste heat boiler—economizer, evaporator, superheater, and reheater components—and compatible with variable load operation of the gas turbine at both partial and full loads.

With a long service life, exhibiting resistance to oxidation, thermal fatigue, and media corrosion, matching the design life of the waste heat boiler's pressure components and reducing capital replacement expenditures throughout its life cycle.