The Use of Volumetric Reflectors for Adjusting Ultrasonic Testing Parameters

In ultrasonic flaw detection, lateral cylindrical drilling is traditionally used to adjust and check equipment parameters. Other volumetric reflectors such as vertical drilling or spherical pores are rarely used. In this article, it is noted that volumetric reflectors of various types are convenient for use as a model of internal and surface defects of welds. Moreover, drillings of various orientations are easy to manufacture. For a long time, the limitations on using drilling for modeling in ultrasonic nondestructive testing were related to the noise caused by diffraction effects as elastic waves bypass cylindrical cavities. It is noted that these effects are currently well studied. They can be used to identify the type of defects and measure their size. The present paper describes the results of experiments on the observation of scattering of longitudinal and transverse waves with various polarization by cylinders and spheres and provides typical examples of the manifestation and use of these diffraction effects. The expediency of using not only drilling but also spherical pores is also noted. Experiments with scattering of ultrasonic waves by pores were performed on transparent glass samples for clarity. Comparative data are presented showing how diffraction effects manifest themselves on various volumetric cavities. In particular, it is noted that a focusing of signals that envelope spherical pores is observed. Limitations on the pulse duration of ultrasonic waves are noted in which diffraction signals can be used to increase information content in the detection of defects. It is recommended to expand the use of lateral drilling with a diameter of 2 mm in samples to adjust sensitivity during ultrasonic monitoring with an echometer.