Pipe nipple from Bar stock

[kevlar49]

We are in the middle of a refinery turnaround. A vendor is stating that they can provide 1.25Cr pipe nipples from bar stock, but they not from pipe. Are there any concerns with this? I am not even sure if it is allowed by B31.3.

One concern that came to mind was if the bar was not forged sufficiently and some cast structure is still left, then I may have a potentially weaker material.

Does anyone else have any concerns/experience with this?

 

[metengr]

kevlar49;
Yes, pipe nipples shall not be manufactured from bar. The pipe nipples should be furnished under an ASTM specification, like A 335, and not machined from bar for ASME B31 Power Piping applications.

 

[metengr]

kevlar49;
There is one option that you may consider. If you review ASTM A 336, it is possible to have pipe nipples manufactured from forged bar ordered under the A 335 specification. It would designated as F11 material.