Dakota Ultrasonics DFX-7 plus MANUAL1 - Manual (Page 81)

DFX-7 Ultrasonic Flaw Detector
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DVK (Curvature Correction): If a V1/K1 or V2/K2 (A2/A4, IIW/Kidney) calibration
standard is used as a reference reflector, the curved surface offers additional focus
normally resulting in greater signal output. DVK is a correction to the gain, in order to
simulate the amplitude generated from a flat back wall. This will typically result in an
overall gain increase.
Material Loss: Used to correct for the attenuation (loss) of sound energy in the test
material; in units of dB/in. or dB/meter. Should be considered during inspections
where the sound has to travel long distances, or the material is very attenuative.
Reference Loss: Used to correction for the attenuation (loss) of sound energy in the
calibration/reference standard; in units of dB/in. or dB/meter.
Transfer Loss: Correction factor to account for the loss of sound energy from
surface condition/roughness or inadequate coupling between the transducer and test
specimen. The surface condition of calibration/reference standards and actual
material being tested in the field will typically vary. This is generally approximated
based on the inspectors experience in the field. Units are dB/in., or dB/meter.
10.6 Creating a DGS Curve
This section provides a step by step procedure to create a TCG curve. Note: a two
point calibration should be done prior to proceeding. Refer to Chapter Five for the
calibration procedures. Also, if the TRIG function will be used, it should be setup
prior to proceeding. Refer to Chapter Six for the setup procedure.
Setting DGS Parameters