SU1298655A1 - Ultrasonic shadow immersion flaw detector - Google Patents

Abstract

The invention relates to the field of non-destructive testing of materials and can be used for automated ultrasonic testing of hot rolled metallurgical products, in particular sheets. The aim of the invention is to increase the reliability of monitoring by providing the possibility of an objective determination of the threshold level of registration of defects. When the flaw detector is in operation, the receiving transducer senses pulses that have passed through both the controlled product 26 and the immersion liquid, in the absence of a controlled product 26 between converters 2 and 3. At the output of the first BAN 10 circuit, there are only waiting pulses of 9 rectangular pulses corresponding to sending ultrasonic signals to a controlled product i (L to s 00 a JV SL

Description

26, The second and third binary decimal counters 14 and 19 count the number of ultrasonic pulses transmitted through the monitored item 265 whose amplitudes (after amplification) exceed the threshold values U, and U, respectively. The second BAN 22 scheme together with the serial shift register 21 emits pulses, corresponding to the beginning of the emissions of the amplitude envelope of the transmitted pulses beyond the threshold U. ,, The number of these emissions is counted by a quarter binary counter of 23 pulses. Total amount

The invention relates to non-disruptive control of materials and can be used for automated ultrasonic testing of hot rolled metallurgical products, in particular sheets.

The purpose of the invention is to increase the reliability of control by providing the possibility of an objective determination of the threshold level of registration of defects.

Figure 1 shows the block diagram of the ultrasonic shadow immersion flaw detector; 2 shows timing diagrams for his work.

The ultrasonic shadow immersion flaw detector contains series-connected high-frequency pulse generator 1, acoustically coupled radiating 2 and receiving 3 transducers, amplifier 4, first controlled amplitude discriminator 5 and recorder 6, amplitude discriminator 7 connected between the output of amplifier 4 and the second input of recorder 6, connected to the second output of the generator 1 high-frequency pulses in series connected block 8 of the delay, the generator 9 of rectangular pulses, the first scheme BAN 10, the first pulse counter 11, the first trigger 12, the first AND circuit 13, the second pulse counter 14 and the first digital indicator 15, the second controlled amplitude drive K of the pulses being analyzed are determined by the capacity of the first pulse counter 11, which overflows on the first digital indicator 15 shows the number of pulses N ,, npeBbimamLi ix threshold U, on the second digital indicator 20 - the number of pulses N, j, the threshold above and, and on the third digital indicator 24 - the number of emissions of the N envelope of the amplitudes of the pulses per level. and From the data obtained, the average value and coefficient of variation of the amplitudes are determined, from which the working registration threshold is calculated. 2 or

the criminator 16 connected between the output of the amplifier 4 and the second input of the first circuit AND 13, connected to the output of the amplifier 4 are connected in series the third controlled amplitude discriminator 17, the second circuit AND 18, the third pulse counter 19 and the second digital indicator 20 connected to the second output of the generator 1 high-frequency pulses, serially connected serial shift register 21, the second BANE 22, the fourth counter of 23 pulses and the third digital

Ind Ikator 24, the second trigger 25, the output connected to the second input of the first trigger and the reset inputs of the four counters 11, 14, 19 and 23 pulses, the output of the first trigger 12

connected to the second input of the second circuit And 18, the output of the first BREAD 10 circuit is connected to the third inputs of the first 13 and second 18 And circuits, the first input of the second counter 11 pulses, the second inputs of the serial shift register 21 and the second BAN circuit 22 are combined, the second input of the first circuit BAN 10 is connected to the second output of the amplitude discriminator 7.

Ultrasonic shadow immersion flaw detector works as follows.

After the start signal, the first trigger 12 goes to

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1 and a high voltage level at its output prepares the first 13 and second 18 circuits for signaling. The high-frequency pulse generator 1 periodically voids the radiating transducer 2 (Fig. 2a) and, in the immersion liquid and the controlled product 26, ultrasonic pulses received by the receiving transducer 3 and amplified by the amplifier 4 (Fig. 2b) propagate. The first amplitude-controlled discriminator 5 compares the amplitudes of these pulses with a constant voltage and generates signals about the presence or absence of a defect, which are recorded by the recorder 6. At the same time, the amplitude discriminator 7, analyzing the amplitude take it

signal, decides on the absence or presence of the controlled product 26 between the converters 2 and 3. In the first case, the output of the signal 1, in the second - the signal O (Fig, 2c). These signals are fed to the control input of the first BAN 10 circuit.

Simultaneously with the sending of pulses, the generator 1 of high-frequency pulses through block 8 of the delay starts the waiting generator 9 of rectangular pulses, which produces pulses (Fig. 2d). The delay time in the delay block 8 should not be less than the propagation time of the ultrasonic pulses from the radiating to the receiving transducer in the absence of the monitored product 26. The pulse of the 9-square pulse generator is fed to the signal input of the first BANE 10. The output pulse will only be when there is a controlled product between converters 2 and 3, i.e. the output of the amplitude discriminator 7 is low (figd). The pulses from the output of the first BANGE 10 circuit are applied to the counting input of the first counter of 11 pulses, which counts the specified number N of packets into the counter.

a workable product 26. At the same time, pulses from the output of amplifier 4 are fed to the inputs of the second and third controlled amplitude discriminators 16 and 17,

At the output of the second controlled amplitude discriminator 16, the pulse is scanned only if

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O

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five

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0

five

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Plyuda received signal exceeds the level and (Fig, 2e). These pulses are fed to the second input of the first circuit AND 13. If they coincide with the pulses at the output of the first BANECH circuit 10, then the pulses appear at the output of the first circuit AND 13 (Fig. 2g). These signals correspond to ultrasound pulses that have passed through the test item 26 and are superior in amplitude to the level and ,. Their number N is counted by the second pulse counter 14 and indicated by the first digital indicator 15. Similarly, the third controls the amplitude discriminator 17, the second AND 18 circuit, the third counter 19 of pulses and the second digital indicator 20 counts and indicates the number N of pulses, the signal O , and in 1, (figs, 2i).

N pulses outputting the level U, Simultaneously the pulses from the output of the first circuit And 13 are fed to the signal inputs of the serial shift register 21 and the second circuit BANGE 22. The information in the serial register 21 is advanced by the clock pulses produced in the generator 1 of high frequency pulses, the output signal level the sequential shift register 21 corresponds to a signal at its input delayed by a clock (FIG. 2h).

Signal 1 at the output of the second prohibition, BAN 22, appears only in the case when, in the previous clock cycle at the end of X5), the circuit AND 13 is a given clock signal - i.e. the envelope of the amplitude of the signals starts to be released for the level U. The number Nj of pulses from the output of the second BAN circuit 22 is counted by the fourth counter of 23 pulses and indicated by the third digital indicator 24. After the specified number N of ultrasonic pulses passed through the test article, the first counter of 11 pulses is analyzed overflows, the overflow pulse enters the input of the first trigger 12 and transfers it. At the first input of the first circuit, And 13 and the second input of the second circuit, And 18, a low voltage level prohibits the passage of signals through them. Digital indicators 15, 20 and 24 show the numbers N ,, N .j N3, from which the necessary parameters that characterize the fluctuations of the signal amplitudes are calculated, and the value of the operating threshold is selected from them. With fixed values of U, and U, these calculations can be done in advance and presented in the form of graphs or tables, according to which the measured parameters are determined from the measured N, N, Ng. It is advisable to carry out the operation of determining the fluctuation parameters on the first of a batch of sheets of the same type that are subject to control.

The invention makes it possible to improve the metrological properties of the flaw detector due to a more accurate setting of the working threshold for registering defects, taking into account the actual parameters of the fluctuations of the receive signals in dx signals on the defect-free areas of monitored products.

Claims (1)

Invention Formula Ultrasonic shadow immersion flaw detector containing series-connected high-frequency pulse generator, acoustically coupled emitting and receiving transducers, amplifier, first controlled amplitude discriminator and recorder, amplitude discriminator connected between the amplifier output and the second input of the recorder, connected to the second output of the high-frequency pulse generator sequentially coupled delay unit and square pulse generator, characterized by five By the fact that, in order to increase the reliability of the control, it is equipped with connected to the generator output of rectangular pulses sequentially connected by the first BAN circuit, the first pulse counter, the first trigger, the first And circuit, the second pulse counter and the first digital indicator, the second controlled amplitude a discriminator connected between the output of the amplifier and the second input of the first circuit AND connected to the output of the amplifier connected in series by a third controlled amplitude discriminator, the second circuit And I, the third pulse counter and the second digital indicator connected to the second output of the high-frequency pulse generator are serially connected by a sequential shift register, the second prohibition scheme, the fourth pulse counter and the third digital indicator, the second trigger, the output connected to the second input of the first trigger and the reset inputs four pulse counters, the output of the first trigger is connected to the second input of the second circuit, And the output of the first, the BAN circuit connected to the third inputs of the first and second c and m, the first counter input of the second pulse, the second inputs of the serial shift register circuit and a second inverted obedi5 Nena and the second input of the first inverted Scheme connected to the second output of the amplitude discriminator. 0 Water Hum but P P P  to. 2 Editor M. Blanan Compiled by K. Leonov Tehred L. Serdyukova. Corrector; L, Patay 882/46 Circulation 777 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, .g. Uzhgorod, st. Project, 4 Above . Bbftue P P P P P