Calibrating Coating-Material Acoustical Velocity - GE MFE DMS 2 Operating Manual

8.4.4

Calibrating Coating-Material Acoustical Velocity

To accurately measure material and coating thickness in
T-COAT mode, the acoustic velocity of the coating must be
entered in the DMS 2. The default value of coating acoustical
velocity is 0.0935 inch/µsec. We recommend that you use the
following procedure to determine the acoustical velocity of
coatings.
Step 1: Obtain a calibration standard of known thickness with
coating on only one side. Be sure that your coated standard is
coated with the same type of coating as your test piece. (See
Figure 8-4 for a typical coated calibration standard design.)
FIGURE 8-4—These are typical examples of coated calibration standards. Note that the base-metal
thickness must be the same throughout the length of the block.
DMS 2 Operating Manual
8. Application Notes and Optional Features
Step 2: Press
and follow the on-screen procedure first
coupling to the probe zero block, then the velocity reference
block.
Step 3: Couple the probe to the uncoated side of the coated
calibration standard . Press
the displayed thickness matches the material thickness (do not
include the coating thickness) of the coated-calibration
standard.
below the THICK selection until
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