SU1728658A1 - Method of ultrasound checking of thickness of plane parallel sample - Google Patents

Abstract

The invention relates to instrumentation technology and can be used in metallurgy, mechanical engineering and other industries to control the wall thickness of products with a coarse-grained structure with one-sided access. The goal is to improve the accuracy of measurements in samples of coarse-grained materials and to simplify the method. The goal is achieved by preliminarily calculating the average speed of ultrasonic fluctuations of Sulfur in the sample material, choosing the angle of incidence of oscillations on the surface of the specimen corresponding to an input angle of 45 & into the sample with a speed of Ser, ultrasonic vibrations in the controlled sample are excited at the same angle of incidence, and the thickness of the sample is calculated taking into account Ser. 1 il. cl

Description

The invention relates to instrumentation technology and can be used in metallurgy, mechanical engineering and other industries in the control of wall thickness of products with a coarse-grained structure with one-sided access.

The known method of ultrasonic control of the wall thickness of the products, which consists in excitation, reception of the longitudinal ultrasonic waves passing through it, measures their passage time by which the thickness is judged.

The closest technical solution is the ultrasonic control method, which consists in:

impulses of ultrasonic vibrations are introduced at an angle to its surface, echo signals reflected from the opposite surface are received, the time delay of the echo signals relative to the excited pulses is measured, and taking it into account, the sample thickness is calculated:

1st oo

ten

sl with

0.5 Wa Pi Pi +

 Cfti-tr) and (aL-aT) sinaJ

where a is the angle of entry of ultrasonic waves in the product, hail;

C is the velocity of longitudinal waves in the material of the transducers, cm / s;

ti, XT is the propagation time of longitudinal and shear waves;

ai, at are the distances from the point of entry to the point of reception, respectively, of longitudinal and shear waves.

The disadvantage of these methods is the large laboriousness and low accuracy of measurements in samples of coarse-grained materials.

The purpose of the invention is to improve the accuracy of measurements in samples of coarse-grained materials and simplify the method.

The goal is achieved by preliminarily calculating the average speed of ultrasonic fluctuations of Sulfur in the sample material, choosing the angle of incidence of ultrasonic oscillations on the surface of the specimen corresponding to an insertion angle of 45 ° into the sample with the speed of ultrasonic oscillations of Sulfur, at the same angle of incidence excite ultrasonic oscillations in the test sample The sample thickness is calculated taking Ser.

The drawing shows a diagram of the implementation of the method.

The circuit contains a transducer 1 and a receiving transducer 2 placed on sample 3. The position "denotes the angle of inclination of the acoustic axis of the transducer, T, L-rays, respectively, of shear waves, am, ai - the distance from the input point to the receive point, respectively, of shear and longitudinal waves.

The method is as follows.

To ensure a minimum measurement error, a gray is preliminarily determined when ultrasound is inserted at an angle of 45 ° in the sample with an average attenuation of ultrasound. Then excite the ultrasound under

the same angle in a controlled sample, receive echo signals reflected from the opposite surface, measure the time delay of the echo signals relative to the pulses being excited, measure ai and at - the distance between the input and reception points of the longitudinal and shear ultrasonic waves, respectively, and the thickness yut by the formula:

h 0.5

YaL

Q / tt-ti)

(aL-ar) sinaJ

Claims (1)

The invention The method of ultrasound monitoring the thickness of a plane-parallel sample, which consists in introducing pulses of ultrasonic vibrations at an angle to its surface, receiving echoes reflected from the opposite surface, measuring the time delay of the echo signal relative to the excited pulses and taking it into account calculate the sample thickness, characterized in that, in order to increase the measurement accuracy in samples of coarse-grained materials and to simplify the method, the average the speed of ultrasonic fluctuations in the sample material, choose the angle of incidence of ultrasonic vibrations on the surface of the sample corresponding to the angle of entry 45 ° in the sample with the speed of ultrasonic oscillations gray; at the same angle of incidence excite ultrasonic vibrations in the test sample, and calculate the thickness of the sample .