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480 views
09:26 Sep-19-1996

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1199
TOFD Probes

Most probes used for TOFD are circular or nearly square.
Would it be feasible or practical to use a rectangular
shaped element to effectively increase the energy input
to a thick test piece? e.g. a 6mm x 18mm element. The
small vertical dimension (6mm) would be intended to
preserve the increased divergence angle needed for TOFD.

If so, would the receiver probe need to be of the same
dimension?




 
09:17 Sep-20-1996
Rathgeb/Meier
Re: TOFD Probes : Most probes used for TOFD are circular or nearly square.
: Would it be feasible or practical to use a rectangular
: shaped element to effectively increase the energy input
: to a thick test piece? e.g. a 6mm x 18mm element. The
: small vertical dimension (6mm) would be intended to
: preserve the increased divergence angle needed for TOFD.

: If so, would the receiver probe need to be of the same
: dimension?

Many thanks for your question.

Siemens does not have so much experience in TOFD-technique,but
we asked experts from AEA in England. AEA did some investigations
to this problem and have bad experience with squared ore rectangular
shaped probes: The parallel edges of squared or rectangular probes
cause interferencies due to diffraction at the crystal edges.
This will reduce your signal to noise ratio and should therefore
be avoided. AEA experience is, that in case of steel material the
diameter of the probe is not so much limited.

If you do need an increase of energy and want to get a smaler
beam width in the horizontal direction, you should better use
elliptical transducers.

To cover a maximal area of inspection, the beam width of the
transmitter and the receiver should correspond.




 


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