Features of the Development of Calibration Specimens for Monitoring Ultra-Acoustic Flaw Detectors. Part 1. General Principles for the Construction of Calibration Specimens

Special features in the use of calibration specimens (certified reference materials) in nondestructive testing are considered. It is shown that calibration specimens are articles for which the coupling parameters, which express the dependence of the information signal of the nondestructive testing instruments on the geometry of the defect models and the physical properties of the test material, should be normalized. It is established that calibration specimens for use in control of the nonlinearity of the electroacoustic channel of an ultra-acoustic flaw detector do not presently exist and that it is necessary to create a new group of calibration specimens, for example, in the form of a multi-element solid-state construction containing defect models of the same type. Through the use of such calibration specimens, it will become possible to identify poor-quality ultra-acoustic flaw detectors.