Section 6: Selected Applications & Techniques

The second step in the inspection involves using an angle beam transducer
to inspect the actual weld. Angle beam transducers use the principles of
refraction and mode conversion to produce refracted shear or longitudinal
waves in the test material. [Note: Many AWS inspections are performed using
refracted shear waves. However, material having a large grain structure, such
as stainless steel may require refracted longitudinal waves for successful
inspections.] This inspection may include the root, sidewall, crown, and heataffected
zones of a weld. The process involves scanning the surface of the
material around the weldment with the transducer. This refracted sound wave
will bounce off a reflector (discontinuity) in the path of the sound beam. With
proper angle beam techniques, echoes returned from the weld zone may
allow the operator to determine the location and type of discontinuity.