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isolated acoustically from one another by a sound-absorbing barrier between them. They are
electrically isolated as well; one serves as a transmitter, the other as a receiver. The ultrasonic
instrument must provide the capability of isolating the pulser and receiver, as does the TG400.
Practical minimum thickness resolution from a dual element transducer optimized for thickness
gaging is approximately 0.040 inch (1.0mm). Typical frequencies for thickness gaging
applications range from 2.25 to 10 MHZ, and the elements can be semi-circular or rectangular.
While again it is only possible to generalize the applications, dual elements provide a good
balance among resolution, penetration and sensitivity.
Procedures for using dual element transducers are outlined in Section 4.3.2.5.
3.3 Transducers for Non-Metallic Test Materials.
Virtually all the techniques and applications described above can be applied to a host of
non-metallic and composite materials. It is not possible to cover the numerous applications in this
manual. Transducer selection for non-metals often is much more involved. However, The TG400’s
unique design can accommodate a huge variety of transducer types. For advice, contact our
Transducer Applications Specialists. Often a transducer can he recommended on the basis of a
description of the application. If not, it may he necessary to submit samples of the test material.
3.4 Transducers for Specialized Applications.
Ultrasonic testing techniques have applications beyond those traditionally though of regarding
flaw detection and thickness gaging. There are applications in material characterization, flaw
analysis, extensometry, bondtesting, liquid level sensing, velocity measurement, and others in
more or less limited usage. In some cases, because the application is specialized, so must be
the transducers.
