TO ASSESS THE RATIO OF ECHO SIGNAL LEVELS AND STRUCTURAL NOISE DURING ULTRASONIC TESTING OF CERTAIN TYPES OF STEEL USED IN THE MANUFACTURE OF NUCLEAR POWER PLANT EQUIPMENT

Abstract

Based on computer modeling, the signal-to-noise ratio estimates are made for models of reflectors in the form of a side drilled hole and a round flat bottom hole small size during ultrasonic method by an angle probe of products made of a number of types of steel used in the manufacture of equipment for nuclear power plants. It is shown that for steels of types 20, 12X1MF and 10GN2MFA, the ratio of the levels of the echo signal and structural noise (signal/noise) for both models with a large margin satisfy the criterion of Prof. I. N. Ermolov reliable detection of a useful echo signal. For steel of type 15X2MFA-A, due to a sufficiently large value of the average grain size and, accordingly, an increased level of structural noise, the signal-to-noise ratio may not meet the criterion of Prof. I. N. Ermolov, which necessitates an increase in this ratio, for example, by increasing the damping of the piezoelectric plate of the angle probe. To increase the signal-to-noise ratio and increase the amplitude of the echo signal, it may be advisable to use a angle probe with a composite piezoelectric plate.