ASTM A376 TP347H solid Spiral High Frequency weld HFW Fin Tube With 11Cr
This is a fintube that uses ASTM A376 TP347H austenitic stainless steel bare tube as the base tube and is covered with 11% chromium (11Cr) low-alloy steel fins.
The base tube has excellent high-temperature strength, creep resistance and corrosion resistance, and is suitable for high-pressure and high-temperature conditions (such as power station boiler superheaters); 11Cr steel fins are low-cost and have a certain resistance to high-temperature oxidation, and are often used for contact with external flue gas/airflow.
This design optimizes costs while meeting the stringent requirements of the internal medium, but it is necessary to be vigilant about the electrochemical corrosion that may occur between the stainless steel base tube and the low-alloy steel fins in a humid/electrolyte environment, and ensure that the operating temperature of the fin does not exceed its oxidation resistance limit (about 650℃). It is mainly used in high-temperature heat exchangers, waste heat boilers and other equipment.
Element | 347 | 347H |
Chromium | 17.00 min.-19.00 max. | 17.00 min.-19.00 max. |
Nickel | 9.00 min.-13.00 max. | 9.00 min.-13.00 max. |
Carbon | 0.08 | 0.04 min.-0.10 max. |
Manganese | 2.00 | 2.00 |
Phosphorus | 0.045 | 0.045 |
Sulfur | 0.03 | 0.03 |
Silicon | 0.75 | 0.75 |
Columbium & Tantalum | 10 x (C + N) min.-1.00 max. | 8 x (C + N) min.-1.00 max. |
Iron | Balance | Balance |
Yield Strength 0.2% Offset | Ultimate Tensile Strength | Elongation in 2 in. | Hardness | ||
psi (min.) | (MPa) | psi (min.) | (MPa) | % (min.) | (max.) |
30,000 | 205 | 75,000 | 515 | 40 | 201 Brinell |
Application
Power station boilers: economizers, air preheaters, using flue gas waste heat to preheat air/feed water.
Waste heat generator (HRSG): Recover gas turbine exhaust heat to improve overall energy efficiency.
Heating furnace convection section: Increase the preheating temperature of crude oil, heavy oil and other media (e.g. atmospheric pressure furnace, reduced pressure furnace).
Catalytic cracking unit: Regeneration flue gas waste heat recovery (high wear and corrosion resistance requirements).
Natural gas processing: acid gas (H₂S/CO₂) heat exchanger (requires sulfur-resistant materials such as N08825/duplex steel).
Industrial boilers and heating, high-efficiency condensing boilers