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MEASUREMENT
To avoid this effect, the specimen has to be thick enough to allow the os-
cillations to attenuate before the diamond is reached. At thin blocks or
round stock, the total mass of the specimen has an effect. If the mass of
the specimen is high enough, a thickness of 8 mm for flat specimen or 10
mm for round stock is sufficient. If a specimen does not meet these re-
quirements, it can be acoustically coupled to a massive support e.g. with
a thin oil film between specimen and support. A solid steel plate is rec-
ommended as support (e.g. the precision stand comes with an appropri-
ate plate).
Small, irregular shaped parts can be embedded in plastic.
Homogeneity
As in optical Vickers hardness tests, the indentations are quite small.
Therefore the homogeneity of the specimen can possibly influence the
measurement results. To achieve reproducible hardness readings, the in-
dentation must be significantly greater than the grain size of the test ma-
terial. This may be not the case for some cast material even with a test
load of 100 N.
5.2 Measuring parameter
The measuring parameter must be set according to the demands. The
parameter are in particular:
These parameter are described in detail in chapter 6.2. Select the menu item
Measuring parameter/Edit to adjust them. If a set of measuring parameter that
meets the requirement has already been saved, you can use the menu item
Measuring parameter/Load (see 6.2.3) to reload them.
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Material
Hardness scale
Rating
Statistics
Instant printout
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