Immersion Inspection is an examination method where the search unit and the material are submerged in a tank of
water (Figure 5-2 and Figure 5-3), or a water column is maintained between the search unit and material. The water
shall be free of visible air bubbles and other foreign material that could interfere with ultrasonic tests. If necessary, a
suitable corrosion inhibiting agent and a wetting agent shall be added to the water to inhibit corrosion and to reduce the
formation of air bubbles on the material and the transducer. The inhibiting and wetting agents shall have been
previously determined to be suitable for the materials to be inspected.
Figure 5-3. Immersion Method.
Ultrasonic sound beams have properties similar to light beams. For example, when an ultrasonic beam strikes an
interrupting object, sound beam energy is reflected from the surface of the interrupting object. The angle of incidence
is equal to the angle of reflection (see Figure 5-4.).