I guess I really knew the answers before I asked. Just looking to confirm my suspicions.
And, no, there was no purge gas used as it was a socket weld. In hindsight, It should have been purged with inert gas even so. I don't think there was actual sugaring present, just the possibility...
I know this has been gone over before.
I have recently had a piping failure with an acid system for ph level control. The piping is 316 stainless. The original piping appeared to be 1/2" socket weld but had a repair/replacement with threaded ball valves which were subsequently welded over the...