YUSHI INSTRUMENTS
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4.2.3 Measurement of the Sound Velocity of the Material
1. Set the approximate sound velocity of the material on the sound velocity submenu under the
parameter menu;
2. Couple the probe to the known calibration position of the calibration block (the sound path is known),
open Gate A, adjust the start position of the gate to let Gate A catch the primary echo; open Gate B and
adjust the start position of the gate to let Gate B to catch the second echo.
3. On the gate menu, set the display as Sba, at this point, there appears a ba sign on the screen.
4. Increase or decrease the sound velocity value of the material till the ba value on the screen is equal to
the sound path distance of the calibration block, at this point, the sound velocity is the sound velocity of
the material.
4.3 Calibration of the Angle Beam Probe
Concerning the contact detection by angle beam probe, distance calibration is a must before any
detection task. There are various kinds of angle beam probes with different structures and sizes, and
different detection objects require different K values, thus the sound paths in wedge blocks are not same,
in other words, the front edge length of each angle beam probe of transverse wave should be measured to
decide the zero-bias value. Along with the probe abrasion during the usage, the angle beam probe need
recalibration after a period time of usage.
4.3.1 Calibration Procedures
Set the sound velocity and sound path of the material known on the parameter menu, primary echo is
adopted generally.
Calibration of the front edge of the probe;
Calibration of the zero of the probe;
Calibration of the probe K value (angle).
Figure 4-3
