SU1385062A1 - Device for ultrasonic control - Google Patents

Abstract

This invention relates to non-regulatory control. The aim of the invention is to increase the accuracy of measuring the thickness of the bleached cast iron layers due to its layer-by-layer sounding. The device contains oppositely placed radiating 3 and receiving 6 transducers fc with acoustic screens 4 and 7, the slit openings 5 and 8 of which are displaced one relative to the other, which makes it possible to fix the moment of change in the velocity of propagation of ultrasonic waves. 1 il. 2 / Q S (L

Description

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The invention relates to non-destructive testing and can be used in ultrasonic testing, in particular, iron castings. The purpose of the invention is to improve the accuracy of measuring the thickness of the bleached cast iron due to its layer-by-layer sound.

The drawing schematically shows a device for ultrasonic testing.

The device for ultrasonic testing includes a housing 1 with immersion liquid 2, a radiating piezotransducer 3 placed on one of the walls of the housing 1, and an acoustic shield 4 with a slot opening 5 installed on the side of its working surface, as well as a receiving transducer 6 placed on the opposite side the wall of the housing 1, and an additional acoustic screen 7 with a slit hole 8 installed on the side of the working surface of the converter. 6

Screens A and 7 are rigidly interconnected and mounted with the possibility of longitudinal movement, for example, on a movable frame (not shown) moving with a micrometer screw (not shown K. Screens 4 and 7 are made of material (for example copper) acoustic impedance exceeding the acoustic impedance of the liquid 2 more than 10 times. The diaphragm slit holes 5 and 6 of screens 4 and 7 are displaced one relative to another by the value of S, corresponding to half their width. whose position is fixed.

The device for ultrasound testing works as follows.

An electrical impulse is applied to the radiating piezoelectric transducer 3 and is converted by it into an acoustic one.

pulse, which through the layer of immersion liquid 2. and through the screen 4 with a slit hole 5 is introduced into the controlled product 9. Since the acoustic resistance of the screen 4 is more than 10 times greater than the acoustic resistance of the liquid 2, the main part of the energy flows through the slit hole 5 into the product 9.

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An acoustic impulse, a passage through the product 9 is received through a layer of immersion liquid 2 and a screen 7 with a slot 8 by a piezoelectric transducer 6, where it is converted into an electrical impulse. With the help of measuring equipment (not shown), the position of the leading edge of the acoustic pulse, which is determined by the total time of passage of the pulse through the layer of liquid 2 and the product 9, is fixed.

Moving the system of screens 4 and 7 with slit holes 5 and 8, layer-by-layer sounding of the bleached, transitional and gray iron zones is carried out.

Since the speed of ultrasonic waves propagated in white iron exceeds their speed in gray iron, the boundaries of the layers are determined by the change in the acoustic impulse transit time and by the device (not shown) reading the position of the screen slots.

The rigid connection of the screens 4 and 7 between them ensures their simultaneous movement and preservation of the constant shift of the slit holes 5 and 8 of one relative to the other.

When the slit hole 8 is displaced relative to the slit hole 5 by half of their width, on the receiving piezoelectric transducer 6 the maximum amplitude of the received pulse is reached.

Thus, in use, the device for ultrasonic testing is twisted accuracy of measuring the depth of the bleached cast iron layers, which are completely in contact with the rubbing surface.

Claims (1)

Invention Formula A device for ultrasonic testing, comprising a housing with an immersion liquid, a piezotransducer placed on one of the housing walls, and an acoustic screen with a slot opening installed on the side of its working surface, characterized in that, in order to improve the accuracy of measuring the thickness of the bleached cast iron layer, it is provided the second piezo313850624 a transducer and a screen that is more than 10 times lazy now on the opposite wall of the core-exceeds acoustic resistance the screens are rigidly connected between the immersion fluid, and the gaps in themselves, installed with the possibility of screens shifted one relative longitudinal movement and made another at an amount not exceeding from the material, the acoustic resistance is half its width.