"SR" Stamp on Pressure Tank from 1954 2

[grumpiefool]

Does anyone have what "SR" stamp on a data plate would stand for? The tank was built back in 1954 by Chicago Bridge and Iron, but was not registered with the National Board. I assume it stands for Stress Relief, but I do not have a copy of the Code that goes that far back.
Thanks in Advance!

 

[jte]

grumpie-

From the 1952 ASME VIII UG-116(f)(1): The letters SR shall be applied under the Code symbol when the whole vessel has been stress-relieved.

This is the same as the current UG-116(f)(1) except that "SR" has been replaced by "HT" and "stress relieved" has been replaced by "postweld heat treated as provided in UW-10."

jt