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Re: ASTM A36

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On Feb 5, 2006, at 10:40 AM, Carter, Charlie wrote:

I fear the result of a project specification or drawing note that attempts to do well with a general statement like "Contractor to perform random material testing ..." but actually defines nothing about what is required, how the testing is to be performed, or what test result is acceptable.
You're right about this. Any time you specify something, you need criteria and means to resolve the discrepancy. Hard to beat the special requirements in the ASTM specs for this. You need to use your head, of course. Sometimes all it takes is a simple hardness test as part of the acceptance drill. In many cases you can accomplish the same thing with a bend test or just by checking out the results of necessary QA procedures like welder qualification tests.

A mill cert only indicates that the product to which it corresponds meets the same production-testing criteria established in a given ASTM standard.
What you're talking about is a certificate of compliance (CC), which is usually good enough, even for some levels of nuclear QA. The thing about heat analysis is that it doesn't reflect processing variables, which may be important in some cases. If you can rely on your supplier (and your purchasing manager) CC's are plenty good enough. Just be aware that if you have particular issues, like toughness or weldability or you suspect your supplier may be trying to move some previously rejected non-conforming material at a discount (it happens), it's cheaper in the long run to have some tests run as a condition of delivery. You don't want to get a call some Friday afternoon from a site welding supervisor telling you that your material isn't passing the welder qualification bend tests.
Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw(--nospam--at)skypoint.com   | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw/


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