COMPARATIVE ANALYSIS OF METHODS OF ULTRASONIC QUALITY CONTROL OF METALS

Abstract

The article presents a comparative analysis of methods of ultrasonic quality control of metals. The genesis of
ultrasonic control is revealed and the task of realization is established. The principles of ultrasonic control with separation of
the main components are revealed. It is emphasized that the ultrasonic method is based on the principle of direct piezoelectric
effect, when the emitter and receiver of ultrasonic vibrations is a plate cut from a single crystal of quartz or piezoceramic
material. The main characteristics of piezoelectric elements and methods of their interaction are given. Three methods of
ultrasonic quality control of metals are proposed for consideration: shadow, mirror-shadow and echo-pulse methods. It is
emphasized that the mirror-shadow method is based on the analysis of changes in the amplitude of the bottom signal, a sign
of the defect is a decrease in the amplitude of the bottom signal below the threshold level. The scheme of radiation distribution
at the mirror-shadow method is offered and the advantages and disadvantages of the method are determined. It is noted that
for the shadow method control, two transducers are used, which are installed on different sides of the object of control, one
transducer is an emitter, the other a receiver. The scheme of radiation distribution at mirror-shadow and shadow methods is
offered, the advantages and disadvantages of the last are resulted. The echo-pulse method is described, it is emphasized that
the principle of the echo-pulse method is that during the generation of an electric pulse, the ultrasonic transducer generates
oscillations transmitted to the object under control, the same transducer receives the echo signals that are displayed from
defects. The scheme of radiation distribution in the echo-pulse method is given and the advantages and disadvantages of the
method are formed. The diagram of the front of the ultrasonic wave passing on depth of the controlled object is offered. It is
emphasized that in the methods of ultrasonic control the main measured parameter is the amplitude of the echo signal from
the defect.