The lower temperature tolerance range of stainless steel heat exchange tubes is determined by the material type! There are significant differences in the performance of heat exchange tubes made of different materials in low-temperature environments.
304 stainless steel heat exchange tube:
It can maintain good toughness in extremely low temperature environments of -196 ℃ and is suitable for cryogenic equipment such as liquefied natural gas (LNG) storage tanks.
Its austenitic structure is not easily brittle at low temperatures, but attention should be paid to controlling the carbon content below 0.08% to avoid intergranular corrosion risks.
316L stainless steel heat exchange tube:
Due to the addition of molybdenum element (2% -3%), its low-temperature performance is similar to that of 304, but it is more suitable for low-temperature environments containing chloride ion media (such as seawater desalination systems), with a minimum tolerance temperature of -196 ℃.
For a liquid helium temperature environment of -269 ℃, ultra-low carbon austenitic stainless steel (such as 304L) or nickel based alloy heat exchange tubes should be used, which conventional stainless steel may not be able to meet the requirements.
In practical applications, it is necessary to comprehensively evaluate the corrosiveness of the medium, pressure, and thermal cycle frequency. It is recommended to verify the applicability under specific working conditions through low-temperature impact testing.