SU1716426A2 - Ultrasonic shadow immersion flaw detector - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to control hot rolled sheet products in the metallurgical, engineering and other industries. The purpose of the invention is to increase the reliability of monitoring sheet metal by detecting defects such as floken. The sheet metal rolling is performed by the shadow method with the registration of defects such as delaminations. The information obtained at the same time is the main one and is used for the checkout of sheets. At the same time, it is controlled by the echo-through method with high sensitivity, fixing defects only in the middle third of the sheet thickness and registering on the digital indicators the percentage of the additional number of echoes from the defect to the total number of pulses transmitted through the sheet. The information obtained in this case is additional and makes it possible to judge the presence or absence of flocs. 2 Il.

Description

The invention relates to non-destructive ultrasonic testing, which can be used to control rolled metal products in the metallurgical, engineering and other industries and is an improvement on the known device according to the author. Mg 1234768.

Known ultrasonic immersion flaw detector used to control hot rolled sheet metal with a thickness of 20-160 mm, which records defects with a sensitivity of -8 ...- 20 T, according to GOST 22727-88. This device contains a series-connected probe pulse generator, an emitting transducer, a receiving transducer and an amplifier, a time discriminator, a memory unit, a divider, three amplitude-time discriminators, the first inputs of which are connected to the amplifier output, and the second ones - to the output of the probe pulses and the trigger threshold of the second amplitude-time discriminator is set by the output voltage of the divider, and the recorder, consisting of a series connection of the circuit support, the driver of the polling pulse, the circuit And and two electronic keys.

In addition, the flaw detector contains the first trig

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rep, whose two inputs are connected to the output of the first and second amplitude-time discriminators,

a differentiating circuit, an OR circuit, a second trigger, the output of which is connected to the recorder input, and a third trigger, connected between the third amplitude-time discriminator and the second input of the OR circuit. The probes of the memory unit, all triggers, the delay circuit and the second electronic key are also connected to the probe pulse generator.

A disadvantage of the known device is the low reliability of detecting internal discontinuities of the type of flocs (thin tortuous cracks) arising in the process of converting the hydrogen dissolved in the metal to atomic when the rolled metal is cooled.

The aim of the invention is to increase the reliability of the control of sheet metal by detecting defects of the type of floken.

The goal is achieved by the fact that the ultrasonic shadow immersion defectoscope is additionally equipped with a second amplifier, a fourth amplitude-time discriminator, a generator of probing pulses, a second divider, a fourth and fifth triggers, a second delay block, the first and second BREAK schemes, a reset circuit, the first, second and third counters, a generator of counting pulses, a dividing circuit and a display circuit, the input of the second amplifier connected to the output of the first amplifier, and its output - to the first input of the fourth The second amplitude-time discriminator, the input of the generator of the probing pulses is connected to the second output of the generator of the probing pulses, and the output is connected to the second input of the fourth amplitude-time discriminator. The input of the second divider is connected to the output of the memory unit, and its output is connected to the third input of the fourth amplitude-time discriminator, the output of which is connected to the input of the second delay unit. The first input of the first BREED is connected to the output of the delay unit, its second input is connected to the output of the second trigger, and the output is connected to the first input of the first counter, the output of which is connected to the first input of the fifth trigger. In addition, the output of the third trigger is connected to the first inputs of the fourth trigger and the second BAN circuit. The output of the fourth trigger is connected to the first inputs of the dividing circuit, the third counter, the reset circuit and to the second input of the fifth trigger, and the output of the poller of the recorder of the recorder to the second inputs

the fourth trigger, the second BAN circuit and the reset circuit. The output of the counting pulse generator is connected to the second inputs of the dividing circuit and the first counter. The first input of the second counter is connected to the output of the second BREAD scheme, its second passage to the output of the reset circuit, its digital output to the digital input of the division circuit, the output of which is connected to the second input of the third counter. The output of the fifth trigger is connected to the input of the generator of counting pulses and to the third input of the reset circuit. The digital input of the indication circuit is connected to the digital output of the third counter. .

Figure 1 presents the block diagram of the instrument; Fig. 2 shows temporary diagrams explaining his work.

The essence of the invention is the introduction of an additional to the shadow method of the recording channel by the echo-through method, which allows to realize the increased sensitivity of the control. In this case, the echo pulses are recorded not in the full time interval between the first Gui and the second II pulses passed through the product, but only in the time interval corresponding to the central third of the sheet thickness. In the same way as in the DUET equipment, the echo signals are recorded with respect to the amplitude of the first pulse passed through the product, which significantly reduces the effect of signal fluctuations on the control results ....

However, in contrast to the DUET equipment, the signal processing and indication circuit used in the additional device allows you to fix the ratio. N / M in percent: the number N of echo signals exceeding a predetermined threshold level in amplitude (determining the required sensitivity of the control through the echo-through method) and due to defects located in: the middle of the thickness of the part of the sheet and not triggering the shadow channel of the main device to the total number of pulses M passed through the sheet,

The ultrasonic shadow immersion flaw detector contains a series-connected probe pulse generator 1, an acoustically coupled radiating and receiving transducer 2 and 3, a main amplifier 4, a first amplitude-time discriminator 5, a second input connected to the second input of the probe pulse generator 1, the first trigger 6, which differentiates circuit 7, the circuit OR 8, the second trigger 9 and the recorder 10, made of series-connected first delay circuit 11, the driver 12 of the polling pulse, the first circuit AND 13, ervogo and second electronic switches 14 and 15. The second input of the first AND circuit 13 is input to registrar 10. The second input of the second electronic switch 15 and the input of the delay circuit 11 are combined and connected to the output of the generator 1, the probing pulse. The flaw detector also contains a second amplitude-time discriminator 16, the first input of which is connected to the output of amplifier 4, the second input to the third output of the probe pulse generator 1, the output of the second amplitude of the time discriminator 16 connected to the second input of the first trigger 6, connected in series to the third amplitude -time discriminator 17 and the third trigger 18, the output connected to the second input of the circuit OR 8. The first input of the third amplitude-time discriminator is connected to the output of the amplifier 4, its second input d-generator output to the fourth one of the probing pulses. The third input of the first trigger 6, the second inputs of the second and third flip-flops 9 and 18 are combined and connected to the fifth output of the generator 1 of the probe pulses. Serially connected time discriminator 19, block 20 and divider 21 are connected to the output of amplifier 4, the second input of discriminator 19 is connected to the second output of oscillator 1 of probe pulses, the second input of memory block 20 is connected to the fifth output of oscillator 1 of probe pulses. The output of the divider 21 is connected to the third input of the second amplitude-time discriminator 16.

Position 22 denotes a test item. In addition, the flaw detector contains a second amplifier 23, a fourth amplitude-time discriminator 24, a second divider 25, a strobe pulse generator 26, a fourth 27 and fifth 28 triggers, a second delay unit 29, the first 30 and second 31 BAN circuits, circuit 32 reset, the first 33, the second 34 and the third 35 counters, the generator 36 counting pulses, the circuit 37 division and the circuit 38 of the display.

The input of the second amplifier 23 is connected to the output of the first amplifier 4, and its output is connected to the first input of the fourth amplitude-time discriminator 24. The gate generator 26 is connected to the second output of the probe pulse generator, and the output is connected to the second output of the fourth amplitude-time discriminator 24 The input of the second divider 25 is connected to the output of block 20

memory, its output - to the third input of the fourth amplitude-time discriminator 24, the output of which through the second delay block 29 is connected to the first input of the first circuit 30 BAN, the second input of which is connected to the output of the second trigger 9, and its output to the first input first counter 33,

The output of the first counter 33 is connected to the first input of the fifth flip-flop 28. In addition, the output of the third flip-flop 18 is connected to the first outputs of the fourth flip-flop 27 and the second circuit 31 of the BAN. The output of the fourth trigger 27 is connected to the first inputs of dividing circuit 37, the third counter 35, reset circuit 32 and to the second input of the fifth trigger 28, and the output of the driver 12 of the polling pulse of the recorder unit 10 to the second inputs of the fourth trigger 27, and the second BAN circuit 31 and reset circuit 32. The output of the generator 36 counting pulses connected to the second input of the circuit 37 dividing and with the second input of the first counter 33. The first input of the second counter 34 is connected to the output of the second circuit 31 BANCH, its second input to the output of the circuit 32 reset and its digital output - to digital th input dividing circuit 37, whose output is connected to a second input of the third counter 35 the output of the fifth flip-flop 28 is connected to the input of the generator 36 and the count pulses with a third input of the circuit 32 is reset. The digital input of the display circuit 38 is connected to the digital output of the third counter 35.

The flaw detector works as follows.

The probe pulse generator 1 excites the radiating transducer 2 (Fig. 2a) and the elastic oscillations propagate in the acoustic path. Two options are possible: the first is when there is no product between converters 2 and 3; the second is when there is a controlled product between converters 2 and 3.

Figure 2 shows the temporary defectograms of the ultrasonic flaw detector in the following sequence of alternation; product is absent; the product is present; the product is again missing. At the output of the amplifier will be the next sequence of pulses (figv). The pulses from the output of the first amplifier arrive at the first 5, second 16, and third 17 amplitude-time discriminators (AEDs) and to the time discriminator 19. The first, second, and third AEDs receive pulses, respectively, as building signals (Fig. 2d, e, l). At the output of the AED a pulse occurs only if

the signal falls into the time interval specified by the gating pulse, and its amplitude exceeds the set threshold level.

The time discriminator 19 selects the first pulse transmitted through the product. The maximum amplitude of this pulse is memorized in memory block 20, divided by the first divider 21 and fed as a threshold level to the second AVD 16, which is compared with the amplitude of the second pulse passed through the product.

The first AVD 5 serves to isolate the first pulse transmitted through the product and to compare its amplitude with a predetermined threshold. The second AVD 16 serves to isolate the amplitude of the second pulse transmitted through the product and compare it with the threshold specified from the output of the first divider 21. The third AVD 17 - serves to isolate the amplitude of the pulse transmitted through the immersion liquid (in the absence of the product) and compare it with in advance given threshold.

Further, the signals from the first, second and third AEDs arrive at the processing circuit consisting of the first 6, second 9 and third 18 flip-flops, differentiating circuit 7 and the OR 8 circuit, which is designed so that there is a multiple of a defect in the controlled product. shadow control method can be judged by the signal from the output of the second trigger 9 (fig.2p). It is seen that in the presence of a defect in the product, the signal from the output of the trigger 9 (fig.2p) has a high level. The presence between the converters 2 and 3 of the tested product can be judged by the signal from the output of the third trigger 18 (fig.2n). With a product, this signal is low.

Fig. 2p shows the pulse from the output of the polling pulse generator 12, which is generated in each monitoring cycle and delay relative to the generator pulse by a certain amount of delay / sufficient for all the monitored pulses to arrive at the receiving transducer 3.

Additionally, the shadow immersion flaw detector is provided with a recording channel using an echo-through control method. The signals from the output of the first amplifier 4 are fed to the input of the second amplifier 23, where they are amplified to the required value. These signals, similar to those in Fig. 2c, arrive at the fourth AVD 24. The gating pulse generator 26 generates a pulse of Fig. 2t, the duration of which corresponds to the central third of the sheet thickness, and the second divider 25, the threshold of the fourth AVD 24,

The trigger threshold, as can be seen from the structural scheme, is formed depending on the amplitude of the first pulse passing through the product and is equal to U g / K, where K is the division factor of the second divider 25; Ui is the amplitude of the first transmitted pulse. Thus, at the output of the fourth of that AVD 24 there will be a pulse (fig 2u) only when the amplitude of the pulses Uiit and Uiv. in the time interval determined by the selective pulse (FIG. 2t) will exceed the threshold

5 Ui / K. This pulse is delayed by the second delay unit 29 by a certain amount 1b and fed to the first BANE circuit 30. The second input of the first BANE circuit 30 receives a signal (Fig. 2n) from the output of the second trigger 9 and a pulse occurs at its output (Fig. 2p) only when the defect is fixed only through the echo through channel, and not repeatedly through the multiple-shadow one. In the process of monitoring, the number N of these pulses (fig.2f) is considered the first reversible counter 33. At the output of the second BAN 31, there are pulses (fig 2) only when there is a controlled product between converters 2 and 3. This number of pulses (Figure 2x) is considered the second counter 34.

The fourth trigger 27 forms a time interval (FIG. 2c) proportional to the time the product has been between converters 2 and 3. A fifth trigger 28 is sent from the output of the fourth trigger 27, which sets the counting interval (FIG. 2sh)

0 and starts the generator 36 counting pulses. From this point on, the first counter 33 begins to subtract, and when it deducts to zero, an impulse is formed at its output (FIG. 2h), which will transfer the fifth trigger

5 28 to the initial state and thereby stops the counting pulse generator (Fig. 2e). Thus, if before the start of the counting, the first counter 33 counted the number of pulses M, then it will subtract up to the moment when NR 0, where R is the number of pulses (fig 2e) that came from the generator of counting pulses 36. Since for indication the N / M ratio in percent, it is necessary that the number of pulses R N-100 go to the dividing circuit 37 at 5, then the first counter 33 is designed in such a way that at its output a signal is generated (FIG. 2h) when the number R of pulses from the generator output counting pulses 36 is equal to the number N of pulses registered x through the echo through channel multiplied by 100, i.e. R N-100 or

R N- upb 0. The division scheme 37 divides

the number of pulses R N 100 100 per M number which is fed to its digital inputs from the digital outputs of the second counter 34, and outputs the number of pulses

N100 -M- cat ° P ° e is considered third

counter 35 and is displayed by display circuit 38. A signal (Fig. 2b) from the output of the first flip-flop 28 triggers the third counter 35. At the output of the reset circuit 32, pulses are generated (FIG. 2c), which reset the counter 34 when there is no product between the converters 2 and 3 and the end of the count.

Thus, using the proposed device, it is possible to carry out the rolling method of rolling by the shadow method with the sensitivity required by GOST 22727-88 and the registration of defects (mainly delamination) on the defectogram, which is a 1:10 scale dash line - a drawing of a sheet printed on him contours of defects. The information obtained in this case is basic and is used for the checkout of sheets. At the same time, the monitoring is carried out by an echo-through method with high sensitivity, fixing defects only in the middle third of the sheet thickness and recording the percentage N / M ratio on the digital indicators. The information obtained in this case is additional, which makes it possible to judge with a high degree of probability whether there is or no flakes at the box office if the ratio is N / M A, where A is a threshold parameter.

Claims (1)

Claims of the invention Ultrasonic shadow immersion flaw detector according to auth.St. No. 1234768, characterized in that, in order to increase the reliability of controlling sheet metal by detecting defects of the type of flocans, it is additionally equipped with a second amplifier, a fourth amplitude-time discriminator, strobe pulse generator, second divider, fourth and fifth triggers, second delay block, first and second BANKS, reset circuit, first, second and third counters, counting pulse generator, dividing circuit and display circuit, the second input the amplifier is connected to the output of the first amplifier, and its output is connected to the first input of the fourth amplitude-time discriminator, the input of the gating pulse generator is connected to the second output of the probe pulse generator, and the output is from the second the input of the fourth amplitude-time discriminator, the input of the second divider is connected to the output of the memory unit, and its output is connected to the third input of the fourth amplitude-time discriminator, the output of which is connected to the input of the second delay unit, the first input of the first BREW circuit is connected to the output of the unit delays, its second input to the output of the second trigger, and the output to the first input of the first counter, the output of which is connected to the first input of the fifth trigger, in addition, the output of the third trigger is connected to the first inputs of the fourth trigger pa and the second BREAK scheme, the output of the fourth trigger is connected to the first inputs of the dividing circuit, the third counter and the reset circuit and the second input of the fifth trigger, and the output of the poller of the recorder of the recorder block to the second inputs of the fourth trigger, the second BREAK circuit and the reset circuit, output the generator of counting pulses is connected to the second inputs of the dividing circuit and the first counter, the first input of the second counter is connected to the output of the second BAN circuit, its second input to the output of the reset circuit, and its digital output to the digital input of the dividing circuit The output of which is connected to the second input of the third counter — the output of the fifth trigger is connected to the input of the counting pulse generator and to the third input of the reset circuit; the digital input of the display circuit is connected to the digital output of the third counter. with s-