ASTM A335 P5 P9 P11 P22 Fin Tube High Frencuy Welding Serrated Fin
Tube , Solid Fin Tube
Serrated Fin Tube
Serrated Fin Tube is a heat transfer element that enhances heat
transfer with high efficiency. By cutting periodic serrated notches
on the edge of the fin (the depth is usually 20%-40% of the fin
height), the fluid is forced to generate turbulent vortices, which
significantly destroys the thermal boundary layer and improves the
heat transfer efficiency by 30-50% compared to smooth fin tubes.
Its serrated structure has the advantages of anti-fouling, delays
the continuous coverage of dirt, reduces the cleaning frequency and
extends the cleaning cycle. It is especially suitable for
high-viscosity, dusty or easy-to-foul media (such as residual oil,
boiler flue gas, seawater).
Typical applications include petrochemical heating furnaces,
air-cooling islands and environmental protection equipment. The
base tube can be corrosion-resistant and highly thermally
conductive. The initial cost is high, but the long-term energy
efficiency is significant.
The Difference Of Solid Fin Tube And Serrated Fin Tube
Solid Fin Tube uses continuous smooth fins to increase heat
transfer by expanding the surface area. It is suitable for clean
media (such as air and low-pressure steam) and has the advantages
of low flow resistance, high strength and low cost, but it is easy
to foul and has medium heat transfer efficiency.
Serrated Fin Tube cuts serrated notches on the edge of the fins to
increase heat transfer efficiency by 30-50% through forced
turbulence and significantly delays dirt accumulation.
It is especially suitable for high-viscosity and
particle-containing fluids (such as flue gas and residual oil), but
the pressure drop increases by 15-30% and the initial cost is
higher. Key selection principles: Use solid fin tubes for
clean/high-pressure scenarios, select serrated tubes for
dirty/high-efficiency scenarios, and needle-shaped fin tubes are
recommended for ultra-fine dust environments.
CHEMICAL COMPOSITION
Low-Alloy Steel
(Grades) | UNS
equivalent | C≤ | Mn | P≤ | S≤ | Si≤ | Cr | Mo |
| P1 | K11522 | 0.10~0.20 | 0.30~0.80 | 0.025 | 0.025 | 0.10~0.50 | – | 0.44~0.65 |
| P2 | K11547 | 0.10~0.20 | 0.30~0.61 | 0.025 | 0.025 | 0.10~0.30 | 0.50~0.81 | 0.44~0.65 |
| P5 | K41545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 |
| P5b | K51545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.00~2.00 | 4.00~6.00 | 0.44~0.65 |
| P5c | K41245 | 0.12 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 |
| P9 | S50400 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.50~1.00 | 8.00~10.00 | 0.44~0.65 |
| P11 | K11597 | 0.05~0.15 | 0.30~0.61 | 0.025 | 0.025 | 0.50~1.00 | 1.00~1.50 | 0.44~0.65 |
| P12 | K11562 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 0.80~1.25 | 0.44~0.65 |
| P15 | K11578 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.15~1.65 | – | 0.44~0.65 |
| P21 | K31545 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 2.65~3.35 | 0.80~1.60 |
| P22 | K21590 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 1.90~2.60 | 0.87~1.13 |
| P91 | K91560 | 0.08~0.12 | 0.30~0.60 | 0.02 | 0.01 | 0.20~0.50 | 8.00~9.50 | 0.85~1.05 |
| P92 | K92460 | 0.07~0.13 | 0.30~0.60 | 0.02 | 0.01 | 0.5 | 8.50~9.50 | 0.30~0.60 |
MECHANICAL PROPERTIES
| A335 Low-Alloy Pipe | UNS Number | Yield Strength ksi | Tensile Strength ksi | Elongation % | Rockwell | Brinell |
| P1 | K11522 | 30 | 55 | 30 | – | – |
| P2 | K11547 | 30 | 55 | 30 | – | – |
| P5 | K41545 | 40 | 70 | 30 | – | 207 max |
| P9 | S50400 | 30 | 60 | 30 | – | – |
| P11 | K11597 | 30 | 60 | 20 | – | – |
| P12 | K11562 | 32 | 60 | 30 | – | 174 max |
| P22 | K21590 | 30 | 60 | 30 | – | – |
| P91 | K91560 | 60 | 85 | 20 | – | – |
Application:
Power/Energy:
Air Cooling Island (ACC): To deal with dusty flue gas (≤550℃), the
anti-erosion design makes the fin life>15 years, and the heat
transfer efficiency is improved by 35% compared with smooth tubes;
Gas turbine waste heat boiler: Prevent ash blockage in
high-temperature and high-pressure flue gas, and the pressure drop
can be controlled to increase by <20%.
Petrochemical:
Residue oil heating furnace: Handle heavy oil with
viscosity>200cP, the serrated structure inhibits coking, and the
cleaning cycle is extended to 2 years (smooth tube only 6 months);
Catalytic cracking unit: Oil and gas heat exchange with catalyst
particles, 316L stainless steel base tube is resistant to sulfur
corrosion, and the heat transfer coefficient reaches 450W/m²·K.
Environmental protection engineering:
Flue gas desulfurization (FGD): In a wet flue gas environment with
pH=1~3, 2205 duplex stainless steel fins are used to resist acid
dew point corrosion, and the fouling thermal resistance is reduced
by 60%;
Seawater desalination: titanium fins + copper-nickel alloy base
tubes (C70600), with a tolerance of Cl⁻ concentration >
50,000ppm, and the evaporator efficiency is increased by 25%.
Industrial refrigeration:
Ammonia refrigeration evaporator: Aluminum serrated fins resist ice
crystal scaling at low temperatures of -40℃, and defrosting energy
consumption is reduced by 30%.
