In theory, when the stress of the pipeline exceeds the yield strength, and then removing any loading , back to the initial loading conditions, the pipe system would happen self-cold-spring.

However, the B31.3 code allows the stress in operation codition exceeds the yield strength ,when the termperature go back to the amibent condition,does the pipe system happen self cold spring?

If so, the spring selection and the nozzle checking would be different from what the program does.
If not, why?
can anyone give me a clear interpreting?