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The focus has been on need for physical testing in
addition to mill certs.  I am more concerned about the
practice of accepting steel without mill certificates
as long as it passes the physical tests.

The assumption is that the steel has been manufactured
in controlled conditions and that the values in the
mill cert are representative of all of the material in
the batch.  The reality is that manufacturers have
pretty tight control of their product and we have not
had problems by relying on mill certificates.

If we are concerned that there might be breakdowns in
the QC processes of the manufacturer, some spot checks
might be of use.  The question is whether these tests
would be effective.  I believe that it would be
appropriate for AISC certified mills to do random
physical testing of the steel they purchase.  The
frequency of the tests would be calibrated to identify
systemic breakdowns in the manufacturers QC processes
and not to guarantee that all steel meets the
criteria.  These tests would be less disruptive and
easier to manage by the fabricator than individual
project testing requirements.

On the other hand if you have some steel without a
mill cert you do not know who manufactured it nor do
you know whether it all came from the same batch.  It
may also be steel that did not meet specification and
thus the manufacturer sold it on an as is basis.  In
such situations you do not have any expectations of
the variability in properties.  Thus it is
questionable to rely on a few physical tests in
accepting the material for use.  Yet this is done all
the time.  I believe that this is a more likely
problem than having falsified mill certs.

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