SU1631400A1 - Method for cheking material quality by ultrasonics - Google Patents

Abstract

This invention relates to acoustic methods of non-destructive testing. The aim of the invention is to increase the reliability of control by obtaining more accurate information about the change in the spectrum of the echo pulses reflected by the sample material as a result of changes in its physical and mechanical properties. Broadband pulses of ultrasonic sound oscillations emitter 3 to intermediate element 5 are emitted and receiver 4 receive reflected echo pulses. The temporal selector 10 extracts an echo pulse once reflected by the free surface of element 5 and measures its spectrum by block 18. Then install element 5 on sample 6 of the material being monitored, pulses again and receive echo pulses. - sample 6 and the bottom surface of the sample, the echo signals and measure their spectra. To the input of the second channel of the selector 10, signals are sent from the splitter 14, which are transformed by the block 19 into frequency labels. Using the measured spectra, the quality of the material is determined. 2 sec. item f-ly, 2 ill. & About CJ N O O

Description

The invention relates to acoustic methods of non-destructive testing and can be used in the study and control of the physical and mechanical properties of materials.

The purpose of the invention is to increase the reliability of control by obtaining more accurate information about the change in the spectrum of echo pulses reflected by a sample of a material as a result of a change in its physicomechanical properties.

FIG. 1 is a block diagram of a device for ultrasonic quality control of materials; FIG. 2 - spectra of echo pulses, obtained by implementing the method of ultrasonic quality control of materials on duralumin samples.

The method of ultrasonic quality control of materials is as follows.

Pulses of broadband ultrasonic vibrations emit into a solid intermediate element and receive echo pulses reflected by it. The spectrum of the echo pulse once reflected by the free surface of the intermediate element is measured. Then, the broadband oscillation pulses emit through the intermediate element into the sample of the material being monitored and also receive reflected echo pulses. The received echo pulses are recorded at two time intervals and the spectra of the single reflection from the interface of the intermediate element and the sample and the bottom surface of the sample echo pulses are measured.

The quality of the monitored material is determined from the spectra of echo pulses that are once reflected by the interface of the intermediate element and the sample and the bottom surface of the sample, taking into account the previously obtained spectrum of the echo pulse once reflected by the free surface of the intermediate sample.

A device for ultrasonic quality control of materials contains a series-connected sync generator 1 and a generator of 2 pulses. The device also contains a transmitting radiating transducer comprising an emitter 3 and a receiver 4, and an intermediate element 5 of solid sound-transparent material on which the emitter 3 and receiver 4 are mounted. At position 6 (Fig. 1) is a sample of the monitored material.

In addition, the device contains a broadband amplifier 7, a two-channel time selector 8 and a two-channel indicator 9. The device also includes a second two-channel time selector 1JD,

the switch 11, the second generator of 12 pulses, a digital meter 13, a divider-driver of 14 short pulses, a two-channel block of 15 time shifts,

block 16 programs, the second switch 17, block 18 analysis of the spectrum with the recorder 19 and the recorder 20 time lines.

The output of the amplifier 7 is connected to the inputs of the selector 8, the indicator 9 and the selector

0 10, the second inputs of which through the switch 11 are connected to the generator 12 and the divider-former 14. The synchronizer 1 is also connected to the generator 12, the divider-former 14 and the block 16. The generators 2 and 12 are connected to the meter 13. Block 16 programs connected to a block of 15 time shifts. The output of the block 15 is connected to the selectors 8 and 10.

From the outputs of the selector 8 signals through

0, the switch 17 can be fed to the input of the recorder 20. From the outputs of the selector 10 through the switch 17, signals can be fed to the input of the spectrum analyzing unit 18 and lane to the recorder 19. The output of the generator 2 is connected to the radiator 3, and the input of the amplifier 7 is connected to the receiver 4. During the control, the delay line is set on sample 6.

The method of ultrasonic quality control of materials is implemented as follows.

0 way.

Synchronizer 1 provides external start of generator 2, for example, G5-54, which excites emitter 3. Initially, element 5 is in an unloaded state and echo pulse reflected from its free surface through receiver 4 and amplifier 7 is fed to the inputs of the first indicator channels 9, for example C1-99, and selectors 8 and 10, for example C10 70/3.

The signal probed by the selector 8 through the switch 17 is fed to the input of the recorder 20, which records the time trace with the reflected free surface of the element by an echo pulse on the chart tape. The second inputs of the indicator 9 and the selector 8 are fed by rectangular pulses generated by the generator 12, for example, G5-60. Prostrated

0 by the selector 10, the signal through the switch 17 is fed to the input of the spectrum analysis unit 18, for example, SCCH-56. The registrar 19 on the chart tape record the spectrum of the element reflected by the free surface.

5 5 echo pulse. Then the element 5 under a certain pressure is connected with the test sample 6 and the spectrum of the interface 5 element - sample b is recorded and the bottom surface of the sample 6 is echo pulses,

Using indicator 9, the informative portion of the time trace of the reflected signal is visually set for recording and the location of the strobe pulses is selected. The recorder 20 records on a paper tape a selected section of the time trace, time stamps and strobe pulses, which ensure the selection of echo pulses for spectral analysis, which allows one to document the control process. From the output of the divider 14, for example, G5-72, pulses of nanosecond duration are fed to the input of the second channel of the selector 10, with the result that at the output of the second channel of the selector 10 a sequence of pulses is formed, which is fed to the input of block 18.

From the frequency components of the spectrum of the pulses that are within the viewing range established for block 18, responses are recorded, recorded by the recorder 19 in the form of calibration frequency marks. Block 16 of the programs, for example, the G5-75, moves in a discrete strobe-pulse step along the time path. The use of block 16 is most effective when frequent changes are required during monitoring the location of the strobe pulses. The block 16 is connected in series with the block 15, made, for example, in the form of a GD- 56 wood-driven impulse generator, which triggers the sweep of the selectors 8 and 10.

A meter 13, for example, 43-47A, helps determine the time intervals between the clock pulse of generator 2 and the leading edge of the strobe pulse generated by generator 12. The material of element 5 is chosen to provide impedance matching of delay line 5 with receiver 4 and radiator 3, which is possible Receive high-resolution echo and reduce noise. As a result, when the method is implemented, the following are measured: FI (UJJ) is the spectrum of the echo pulse from the free surface of element 5; F2M - the spectrum of the echo pulse from the interface element 5 - sample 6; Pz (s) is the spectrum of the echo pulse from the bottom surface of sample 6 (Fig. 2),

Using the measured values, the reflection coefficient K0tr (w) F2 (w) I Fi (w) is determined; conditional transmission coefficient Tnp (w) РЗ (Й) / Fi (&); loss factor Q (co) Pz (w) / Fz (w) and the parameter of the parameter PSr K0tr (d) Tpr (m) Q (o),

As an example (Fig. 2), the spectra obtained by monitoring duralumin samples F2 (Pz1 (&) spectra obtained on a reference sample) are shown. In this case, P21 ((o) and Pz1 ((a) should not differ in their values, since this parameter characterizes the state

contact surfaces of samples. If there is a mismatch, it is necessary to bring the sample surface to the appropriate reference. The spectra Ps (w), Fs (o) depend on the state of the material and their degree of divergence is determined by the technical conditions. Typically, a certain threshold is established for the Pz (w) spectrum. Samples that form the Pz spectrum ((a) below this threshold are rejected. The quality of the material can be assessed, for example, using the expression APSr PSR-PSR, where PPS is the medium parameter of the reference sample.

Improving the accuracy of control is determined both by the use of a complex value as a criterion for rejection, and by excluding the possibility of influencing the results of monitoring resonant unsteady interference generated in the contact layer, and by recording with an indicator

spectrum frequency tags.

Claims (2)

1. The method of ultrasonic quality control of materials, which consists in emitting broadband pulses of oscillations into a sample of a material, receiving oscillations reflected by a sample of pulses, fixing received pulses during two time intervals, measuring spectrum of recorded pulses and determining the quality of the material from the measured spectra, characterized in that, in order to increase the control accuracy, the emission of broadband vibration pulses into a material sample is carried out through a solid intermediate element, into which broadband vibration pulses are emitted, are reflected by the intermediate element oscillation pulses and measure the spectrum of the echo pulse, once reflected by the free surface of the intermediate element, measure the spectra of one warfare reflected boundary of the intermediate element and the sample and the bottom surface of the sample of the echo pulses, which determine the quality of the material, taking into account the spectrum of the once reflected free surface of the intermediate element of the echo pulse. 2. A device for ultrasonic quality control of materials, containing a series-connected synchronizer, pulse generator, and a radiation transmitter a transducer and amplifier, a time selector and a spectrum analysis unit with an indicator, characterized in that, in order to increase the reliability of the control, it is provided with an intermediate element acoustically connected to the receiving-emitting transducer solid sound-transparent material and a divider-shaper of short pulses, the time selector is made two-channel, the input of the form-divider is connected to the synchronizer output, and the output is connected to the input of the second channel of the time selector. W about FIG. 2 3.2 M, PHz