Oliver recommends Brinell testing for hardness of steel plate, rather
than Rockwell, although we can provide either upon request. A range
of 40 points in Brinell hardness or 4 points of Rockwell is required
for heat treating to a specified hardness. When hardness is requested
in addition to tensile test results, the hardness is for informational
This standardized test for mechanical properties can be done on any
steel. Certain grades, such as A36, A572, A516, or A514, are required
by specification to have certain mechanical properties and these
are reported on the test certificate. C1045, 4140, 4340, and 8620
are chemistry-only grades; they need to be heat treated in order
to guarantee tensile test results.
This is generally done for products going into cold weather applications
but can be done on any steel. Most commonly, A516, A572, and 4340
may require Charpy Impact testing. Usually, thermal treatment in
the form of normalizing or quench-and-temper is necessary to ensure
specific impact test results.
It is often thought that ultrasonic testing (UT) will guarantee internal
soundness of a plate by verifying that there are no internal voids
or impurities. This is inaccurate. A UT procedure scans the plate
using a specified scan or sampling interval, and looks for inconsistencies
in internal structure. If the procedure finds no inconsistencies
that exceed what is allowed by the UT specification, the plate passes.
The choice of UT spec used should be determined by what is acceptable;
the tighter the spec, the more expensive the testing and the more
expensive the material.