Ultrasonic inspection of austenitic cladded steel

A summary of important properties or characteristics associated with the ultrasonic inspection of austenitic cladded materials is presented. These characteristics include attenuation differences, angle beam mis-direction, and zero degree angle beam reflections. The latter characteristic appears as a false 3/8 node shear wave signal, when testing at an angle of 45 degrees. This signal is shown to originate in the unusual grain structure of austenitic cladding. The relative amplitude of the false shear wave indication is shown to vary inversely with the size of the search unit (area) and directly with the test frequency. It is further noted that this effect is sensitive to the direction of clad welding; being significantly greater if the ultrasonic beam is directed perpendicularly to the welding direction. Figures depicting the above conditions are presented together with suggestions for dealing with these adverse testing properties