Why should spin-formed heads not be used for low-temperature vessels?
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I have a question: In the technical agreement for a newly acquired contract, there is a provision regarding low-temperature end caps. I’d like to know why
To share my opinion, for heads formed by spinning, repeated spinning at the arcuate areas leads to relatively high stress concentrations. Moreover, the dimensions of some finished products differ significantly from the theoretical values, making such method unsuitable for low-temperature materials.
Low-temperature vessels, or the materials used in such vessels, are quite sensitive to stress, such as welding stress and processing stress. In some technical requirements, further processing must take place only after the stress has been eliminated; spinning to form vessel heads inevitably generates cold-working stress!
Learn* it. Whether the head is spun or stamped, it still goes through a solution treatment process, right? Is your requirement related only to stress specifications or also to size requirements? The spinning dimensions are not easy to ensure. Expert answer. . . .
I think stress is the main factor; the dimensional deviation can be within the range allowed for elliptical head deviations.
It is a requirement mentioned in the project specifications provided by Party A; and to clarify, does it apply to stress or dimensions? I personally speculate that it is close to the values for the two people on the 1st and 3rd floors, and it is likely related to the stress involved.