GE SpotChecker, Руководство по эксплуатации

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The ultrasonic wave is attenuated in any material. This
sound attenuation is very low, e.g. in parts made of
fi ne-grained steel, likewise in many small parts made
of other materials. However, if the sound wave travels
larger distances through the material, a high cumula-
tive sound attenuation can result even with small at-
tenuation coef
fi cients. There is then a danger that
echoes from natural fl aws appear too small. For this
reason, an estimate must always be made of the ef-
fects of attenuation on the evaluation result and taken
into account if applicable.
If the test object has a rough surface, part of the inci-
dent sound energy will be scattered at its surface and
is not available for the test. The larger this initial scat-
tering, the smaller the
fl aw echoes appear, and the
more errors occur in the evaluation result.
It is therefore important to take the effect of the test
object’s surfaces on the height of the echo into ac-
count ( transfer correction).
Limitations of software
Based on the present state of the art, software cannot
be completely free of faults. Any software-controlled
equipment should therefore be checked before and af-
ter use in order to ensure that the necessary functions
operate perfectly.
Always carry out a check by means of a calibration
standard both before and after the test.
Introduction
Important information on ultrasonic testing
14
Issue 02, 03/2009 SpotChecker