Is heat treatment required for welding stainless steel heat exchange tubes to the tube sheet?
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For refrigeration evaporators using ammonia as the working medium, is heat treatment required for welding the stainless steel (SS304) heat exchange tubes to the tube sheet?
It is not specified by standards; it is determined by the designer, and heat treatment is generally not applied
It is said that welding stainless steel and carbon steel does not require heat treatment.
This post was last edited by gn_1984 on 2015-9-17 at 13:14. Is the floor panel made of carbon steel? To avoid welding of dissimilar steels, it is advisable to use a tube sheet cladding structure for the floor main tube sheet; in this case, the weld joints between the tube sheet and the heat exchange tubes do not require heat treatment. However, if the tube sheet is made of carbon steel and the heat exchange tubes are made of stainless steel, in order to avoid post-weld heat treatment, the person in charge of the selection should have high requirements regarding the welding materials; for specific details, they can refer to the requirements specified in HG/T20581-2011.
It seems there is ammonia stress corrosion, so heat treatment is required. The original poster, please check.
The heat treatment of austenitic stainless steel is generally solution treatment or stabilization treatment, which is difficult for container manufacturers to carry out. Therefore, such heat treatment should be avoided as much as possible.
Stainless steel generally does not require stress-relief heat treatment after welding, and stabilization and solution treatment are also not practiced
Stainless steel undergoes solution treatment or stabilization treatment at the time of production; no heat treatment is required after subsequent welding
Typically, the tube sheet is made of carbon steel; to avoid welding of dissimilar metals, a cladding structure is used for the tube sheet, in which case the welding joint between the tube sheet and the heat exchange tubes does not require heat treatment.