What is the internal stress of metal bellows?

What is the internal stress of metal bellows?
Metal bellows have good compensation function, besides the design link, including manufacturing, installation and so on, which will cause the efficacy of the product and need to grasp more. Therefore, in the normal use of metal bellows, we should pay attention to the design link, and ensure the realization of its functions by selecting materials with care.
Since corrosion damage of metal bellows accounts for most of the damage, it is necessary to combine the causes of corrosive environment and the selection of corrosion-resistant materials. Corrosion of metal bellows generally includes two types of corrosion perforation and stress corrosion cracking. The condition of stress corrosion is the presence of corrosive environment and internal stress. The existence of stress is one of the conditions leading to stress corrosion cracking, the main sources of stress are: bellows processing and forming process deformation stress and residual stress; working pressure during service; improper assembly leads to excessive assembly stress, corrosion products lead to wedging stress.
Flue gas energy recovery system in low temperature conditions prone to chloride ion corrosion, in high temperature conditions prone to sulfide corrosion, the selected metal expansion joint material should be able to group can work under high temperature conditions; in addition, one should avoid producing a corrosive environment, such as the design should avoid cold wall; one should be in equipment decommissioning, cooling before quickly replacing the pipe and metal bellows within the residual flue gas medium, to eliminate the phenomenon of condensation and bellows The deposition of corrosive media inside.
Keep the pipeline dry and ventilation, to take forced ventilation, eliminate the formation and expansion of pitting conditions; one in the operating conditions, with external insulation and other methods to eliminate the environment below the dew point temperature of the working medium; another should try to eliminate stress within the bellows, such as solid solution to eliminate deformation stress and residual stress generated during the processing and forming of the bellows, as well as the metal expansion joint assembly process to avoid the generation of constraint stress etc.