Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

3.17.4 B Scan Block diagram:
B-scan display is a plot of time versus distance, in which
• one orthogonal axis on the display corresponds to elapsed time (depth),
• while the other axis represents the position of the transducer along a line
on the surface of the test piece relative to the position of the transducer at
the start of the inspection.
Echo intensity is not measured directly as it is in A-scan inspection, but is
often indicated semi quantitatively by the relative brightness of echo
indications on an oscilloscope screen. A B-scan display can be likened to an
imaginary cross section through the test piece where both front and back
surfaces are shown in profile. Indications from reflecting interfaces within the
test piece are also shown in profile, and the position, orientation, and depth of
such interfaces along the imaginary cutting plane are revealed.