Comparative Sensitivity of the Acoustic Technique Testing to Internal Defects of Rolled Product Using Longitudinal and Transverse Waves

Samples of rod stock in the form of cylinders made from steel grades 38KhGM and 05Kh16 with real internal defects were investigated. For measurements, an experimental setup was used featuring a specialized through-type EMA transducer for transverse waves with axial polarization at a working frequency of 2.5 MHz, as well as an ultrasonic flaw detector DIO-1000 PA equipped with a piezoelectric converter for longitudinal waves based on flexible PVDF piezo film installed circumferentially via contact liquid, operating at a frequency of 10 MHz. The probabilistic-statistical characteristics of multiple reflection pulse series were analyzed. Their analysis shows that the detectability coefficient parameter is most stable in terms of detecting defects using bulk waves.