Mill Tolerance
Mill Tolerance
(OP)
Good Morning everyone,
My question is, why do we use the 12.5% mill tolerance for seamless pipes in ASME B31.3 only while it is absent in B31.4 & B31.8 for seamless pipes ?
My question is, why do we use the 12.5% mill tolerance for seamless pipes in ASME B31.3 only while it is absent in B31.4 & B31.8 for seamless pipes ?





RE: Mill Tolerance
Thus while all other pipeline codes and many piping ones as well add the tolerance to the calculated wall thickness, in some cases they allow a higher design factor than 32.4 or 31.8.
How this came to pass is not clear to me, but has been in existence for a long time so it has in effect passed into the realms of proven by longevity not to be a significant failure issue.
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RE: Mill Tolerance
RE: Mill Tolerance
RE: Mill Tolerance
That may be true for Pipeline codes such as ASME B31.4 but mill tolerance has to be included in ASME B31.3.
RE: Mill Tolerance
The answer: The mill tolerance is included in the design factor and so doesn't need to be included
RE: Mill Tolerance
Ans: B31.3, 4 & 8 codes were each written by different engineering committes. B31.4 and 8 committes believed in keeping things as simple as possible.