RE: MILL TOLERANCE

From: <Christopher>
Date: Wed Apr 21 2004 - 12:12:00 EDT

>My interest
>is if these limits are truly required by the pipemakers or if they are just
>historical numbers and the makers aim at the lower limit.
That's been my understanding. Given that the weight tolerance is lower than the thickness tolerance, my guess is that concentricity and out-of-roundness is the culprit. There's also a provision in Section VIII that allows opening reinforcement calculations to use the nominal thickness, so I assume all the required metal is somewhere in the cross section.

I've been told that a 12.5% mill tolerance is obsolete because of newer methods of fabrication, but mention of the tolerance still exists in Section VIII. I don't have an up-to-date collection of ASTM Specs, but the last time I looked it was still in specs for carbon steel.

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=PbiU5xf7rNc7t9znMmQdWIAh-cqLipezPKBspEAP3Zwsca8cvo-KKQ79RMXTgifxq77It9uPPS96szb2RQ">chrisw@skypoint.com</a> | this distance" (last words of Gen.

___________________________| John Sedgwick, Spotsylvania 1864)

<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a> Received on Wed Apr 21 12:12:00 2004