Technical Test Requirements; Limitations Of Testing; Ultrasonic Wall Thickness Measurement - GE SpotChecker Operating Manual

Important information on ultrasonic testing

Technical test requirements

Every ultrasonic test is subject to specifi c technical
test requirements. The most important ones are:
❚
the defi nition of the scope of inspection,
❚
the choice of the appropriate test method,
❚
the consideration of material properties,
❚
the determination of the limits for recording and
evaluation.
It is the task of those with overall responsibility for
testing to ensure that the inspector is fully informed
about these requirements. The best basis for such in-
formation is experience with identical test objects. It is
also essential that the relevant test specifi cations are
clearly and completely understood by the inspector.
GE Sensing & Inspection Technologies organizes spe-
cialized training courses in the fi eld of ultrasonic test-
ing at regular time intervals. The scheduled dates for
these courses will be given to you on request.
SpotChecker

Limitations of testing

The information obtained from ultrasonic tests only re-
fers to those parts of the test object which are covered
by the sound beam of the probe used.
Any conclusions from the tested parts to be applied to
the untested parts of the test object should be made
with extreme caution.
Such conclusions are generally only possible in cases
where extensive experience and proven methods of
statistical data acquisition are available.
The sound beam can be completely refl ected from
boundary surfaces within the test object so that fl aws
and refl ection points lying deeper remain undetected.
It is therefore important to make sure that all areas to
be tested in the test object are covered by the sound
beam.

Ultrasonic wall thickness measurement

All ultrasonic wall thickness measurements are based
on a time-of-fl ight measurement. Accurate measure-
ment results require a constant sound velocity in the
test object. In test objects made of steel, even with
Issue 02, 03/2009
Introduction
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