DE2837343A1 - ULTRASONIC PROCESS FOR MATERIAL TESTING AND EQUIPMENT FOR REALIZATION - Google Patents

Description

Vsesojuzny nauchno-issledovatelsky institut po razrabotke nerazrushajuschikh. raetodov i sredstv kontrolya kach.estva materialov

ULTRASONIC PROCESS FOR THE WERiCSO] OPi ¹ PEUMJNG UNi) EIESIGHTUNG FOR THE REALIZATION OF THESSELBEN

The invention relates to methods and means for non-destructive material testing and concerns in particular an ultrasonic method for material testing and a facility to realize the same.

The method according to the invention and the device to realize the same are for use in devices and systems for ultrasonic testing of materials and Products in the metallurgy, mechanical engineering industry, the energy industry and the aircraft construction industry for detection determined by local errors. The invention can are also used in information measuring devices and systems, where pulse signals serve as information carriers.

It is an ultrasonic method for material testing

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known (see for example A.K. Gurwitsch, I.N. Jermolow "Ultrasonic testing of sc jaws sewing". Publishing house "Technika", Kiev, 1972, pp. 66-69), which is involved in the emission of ultrasonic vibrations in the material in which the reception and "processing of the reflected ultrasonic vibrations, in the setting of a level of noise isolation, in the isolation of the signals from the disturbances at the selected level and registration of the test results This procedure is used to set the level of interference separation manually on the basis of the visual observation of the interference level in the range of the maximum test sensitivity.

It is a facility for ultrasonic material testing known who realized this method, in which the output of an ultrasonic generator, whose input with a the outputs of a synchronizer is connected to the input of an ultrasonic transducer, which is acoustically connected to the material to be tested is connected, while the output of the ultrasonic transducer is electrically connected one with a unit for receiving and processing the reflected ultrasonic vibrations in series unit to separate the signals from the interference with the first input of a signal registration unit, the second Input is applied to the second output of the synchronizer, is connected. In the known device, the Unit for separating the signals from the interference is a detector designed with semiconductor diodes with interference separation, the separation level being due to the size

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manually by the operator depending on the ■ Interference level of the material to be tested, the reference voltage set is determined.

As a result of an inhomogeneity of the material structure as well Inadequate acoustic contact can cause even nearby areas of the material of the same test object Interference levels differ significantly from one another.

This is more complicated when testing products Shape and variable thickness made from modern alloys, characterized by a variable structure are the case. Such products include, for example, reactors and pipelines for nuclear power plants.

During the testing of these products, manual adjustment of the noise isolation level is carried out with the known one Establishment of a change in this level in the event of a change in the interference level of the material is not guaranteed.

In addition, optimal test sensitivity is not achieved, because the operator is usually the case with manual settings selects the separation level above the maximum interference value.

Since the level of interference separation is chosen subjectively and errors are missed in the test either because of an excessively high interference separation level or because of a too high level of interference low interference separation levels false defects are registered, the test integrity of the known device degraded.

The test performance for products with sections that

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different structure have noise levels, is also, not high, since from section to section a change in the level of separation and a repeated examination of the section, which differs from the previous one in terms of structural disturbance is required.

It is no less complicated and labor-intensive Adjustment of the facility in the transition to another test item, which s i with regard to the structure interference level differs significantly.

The invention is based on the object of an ultrasound method to specify for material testing and to create a facility for the implementation of the same, in which by perfecting the adjustment of the noise isolation level optimal test sensitivity and security as well as a high test performance in the determination of defects in materials that have different structural noise levels have, is secured.

This is achieved by the fact that in the ultrasonic method for material testing, which is in the radiation of Ultrasonic vibrations in the material, in the absorption and processing of the reflected ultrasonic vibrations, in setting a level of interference isolation in the Area of maximum test sensitivity, in the partition the signals from the disturbances at the selected level and in the registration of the test results, according to of the invention the mentioned level of interference separation for

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each period of ultrasound radiation equal to the mean one

area
Interference power is ^{automatically set during a time interval selected in the v of} the maximum test sensitivity of the previous ultrasonic radiation period.

It is useful in the method in the event that the time interval is in the range of the signals in the presence of interference is selected before setting the noise isolation level in this area a time selection of these disturbances from the signals on a known in advance to set the maximum interference level and to set the separation level according to the level of the selected interference.

This is also achieved in that at the ultrasonic -Werkst off testing device, which the invention Process realized, the output of an ultrasonic generator, whose input is connected to one of the outputs of a synchronizer, to the input of an ultrasonic transducer, which is acoustically coupled to the material to be tested is placed, while the output of the ultrasonic transducer electrically via a unit with a unit for recording and processing the reflected ultrasonic vibrations a series-connected unit for separating the signals from the interference with the first input of a signal registration unit, whose second input is connected to the second output of the synchronizer is, and according to the invention an element for measuring the mean interference power and a time selector, which is a UUD- -Link and a strobe pulse forming circuit, whose input

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gang with the third exit of the Synohronizer and their Output is connected to one of the inputs of the AND gate, the other input of which is connected to the output of the unit for recording and processing the reflected ultrasonic vibrations is placed, while the output of the AND gate is electrically connected to the input of the element for measuring the mean Interference power, its output to the control input of the unit for separating the signals from the interference and to the third input of the signal registration unit is applied, is coupled.

When setting up, it is useful to connect the output of the AND element to the input of the element for measuring the mean To connect disturbance power directly.

It is also useful to also use the time selector another St rob pulse-forming circuit, the input of which is connected to the output of the Ufi'D circuit, and with a UNu-NOT element, the first input of which is electrically connected to the Output of the AND gate is coupled and its second input to the output of the second strobe pulse forming circuit is placed, with the output of the AND-NOT gate is connected to the element for measuring the mean interference power.

It is advantageous to also use the time selector to provide a delay circuit and this between the output of the AND gate and the first input of the AND -NOT-member to switch.

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The ultrasonic method according to the invention for material testing and the device for implementing the same ensure a change in the Störungsabt in the course of the test process Detection level off when the interference level of a workpiece material changes with different structural body rules.

The use of the procedure and the facility for Ultrasonic testing of materials increases the testing performance and security and ensures optimal test sensitivity.

In the following, the invention is illustrated by the description specific exemplary embodiments explained with reference to the accompanying drawings. Show it:

.Fig. 1 shows the block diagram of a device according to the invention for the ultrasonic testing of markings with a Time selector after the first variant

"Fig. 2 is the same, with a time selector after the second execution un _ü 'sv ar iante;

Pig. 3 - the same, with a time selector according to the third variant;

Fig. 4 - Time diagrams a), b), c), d) and e) of the processes in various points of the circuit of the invention Device for ultrasonic testing of materials according to FIG. 1.

Fig. 5 - Time diagrams a), b), c), d), e) and f) of the processes in various points of the circuit of the device according to the invention for ultrasonic testing of materials

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according to i? ig. 2.

The ultrasound ν according to the invention is used for material testing ordered in the following.

Ultrasonic vibrations are radiated into the material, which are recorded reflected by the imperfections and the rear wall of the workpiece. Then these vibrations preprocessing (amplification and rectification) and for each ultrasonic radiation period it is automatically, an interference separation level equal to the average interference power in a certain time interval is set.

This time interval is either in the zone of maximum test sensitivity of the ultrasonic radiation period in the interference-free area or in the area where next to the signals also have interference is selected. These signals include the transmission pulse and that from the faults and the back wall of the test object reflected pulses. as interference-free area is a zone of the ultrasonic radiation period in which the probability of occurrence of signals that are reflected by imperfections, almost equals zero.

liach the adjustment of the noise isolation level, which takes place in the error-free area according to the interference level, the signals are separated from the interference in this area Level and a registration of the test results.

Will be the time interval in which to get the noise isolation level is selected in the area where there are also disturbances in addition to the signals, then before the setting the level of interference separation in this area

temporal selection of the disturbances from the signals made at a maximum disturbance level known in advance, whereupon the level of separation for these is set according to the level of the selected disturbances.

Then the signals are separated from the interference at this level and the test results are recorded performed.

The facility for ultrasonic testing of materials, which implements the above-mentioned method, contains an ultrasonic generator 1 (Fig.l) and one as a blocking oscillator Synchronizer 2 with three outputs, in which one of the outputs is connected to the input of the ultrasonic generator 1 connected is.

The output of the latter is to the input of an ultrasonic transducer 3 connected, which is acoustically coupled to the material of the test specimen 4 shown in section.

The output of the ultrasonic transducer 3 is via a unit 5 for receiving and processing the reflected Ultrasonic vibrations in series unit 6 for separating the signals from the interference, which is designed as a detector with interference separation, electrically with coupled to the first input of the signal registration unit 7.

The unit (5) for receiving and processing the reflekr oriented ultrasonic vibrations represents a preamplifier with time gain control. The signal registration unit 7 contains a display means 8, which has a video amplifier 9, the input of which is connected to the output of the unit 6 for

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Separation of the signals associated with the interference is one Deflection generator 10, the input of which is connected to the second output of the synchronizer 2, and a cathode ray tube 11, on their vertical deflector plates and Horizontal deflection plates each of the video amplifier 9 and the deflection generator are placed, includes.

In addition, the signal registration unit 7 includes a automatic error signal is at or 12 from a strobe pulse switch ung 15, at the input of which the second output of the syn-

c§ra
chronisators 2 is placed, a? AND element 14, in which one input is connected to the output of the strobe pulse circuit 15 and the second input is connected to the output of the unit 6 for separating the signals from the interference, and a test result indicator 15, the first input of which is connected to the output of the AND gate 14 is connected »

The test result indicator 15 has an input threshold element with adjustable response level.

The device according to the invention contains an element 16 for measuring the mean interference power, consisting of one with a t £ uadrier member 18 and a communication member 19 in Series connected input measure st member 17 and a time selector 20, an AND gate 21 and a strobe pulse forming circuit 22, the input of which is connected to the third output of the synchronizer 2, has.

The output of the strobe pulse forming circuit 22 leads to one of the inputs of the AND gate 21, the other input to the output of the unit 5 for recording and processing

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direction of the reflected ultrasonic vibrations is placed.

The output of the UItD-G-Iiedes 21 is connected to the input of the Scale link placed. The output of the averaging element is connected to the control input of the unit 6 for separating the Signals from the malfunctions and to the control input of the test result display 15 connected.

In Pig. The device shown in FIG. 2 contains, in contrast to the circuit of FIG. 1, the time selector 20 additionally a second strobe pulse forming circuit 23 (Fig. 2), the input of which is connected to the output of the AND circuit is placed, and an AND-NOT element 24, the first input of which is connected to the output of the AND element, the second input - to the output of the second strobe pulse forming circuit and the output - with the input of the scale element 1? of Element 16 for measuring the mean interference power are connected.

At the establishment according to Ji'ig. 3 contains the difference of the circuit according to FIG. 2 of the time selector 20 in addition a delay circuit 25 connected between the output of the AND element 21 and the first input of the AND-NIGHT element 24.

In Fig. 1, 2, 3 in the test piece 4 are the defects 26 and the rear wall 27 of the same are shown.

Fig. 4 shows the timing diagrams:

a) for the pulses 28 and 36 at the output of the synchronizer 2 (Fig. 1);

b) for the pulse signals 29 (Fig. 4), 30, 31, 32, 33

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and 54- in the presence of malfunctions at the output of the unit 5 (Fig.l) for recording and processing the reflected ultrasound swings;

c) for the strobe pulse 35 (Fig. 4 ·) at the output of the strobe pulse forming circuit 22 (Fig. 1);

d) for the separated faults at the output of the UHD -Link 2 (Fig. 1);

e) for the pulse signals 29 (Fig. 4-), 30, Jl, 32, 33 and 34 at the output of the unit 6 (Fig.l) for separating the Signals from the disturbances.

Fig. 5 shows the timing diagrams:

a) for the pulses 28 and 36 at the output of the synchronizer 2 (Fig. 2);

b) for the pulse signals 29 (Fig. 5), 30, 31, 32, 33 and 34- % n presence of disturbances at the output of the unit 5 (Fig. 2) for receiving and processing the reflected ultrasonic vibrations;

c) for the strobe pulse 35 (FIG. 5) at the output of the strobe pulse forming circuit 22 (Fig. 2);

d) for the pulse signals 32 (Fig. 5) and 33 in the presence of disturbances at the output of the AND circuit 21 (FIG. 2);

e) for the strobe pulses 37 and 38 at the output of the strobe pulse forming circuit 23 (Fig. 2);

f) for the separated from the signals 32 (Fig. 3) and 33 Disturbances at the output of the ÜHD-NOT circuit 24- (Fig. 2).

The device according to the invention for ultrasonic testing of materials works as follows.

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The first pulse 28 (Pig. 4, diagram a) of the synchronizer 2 (Fig.l) solves; the deflection generator 10, the Strob impulsformier circuits 13 and 22 and the ultrasonic generator 1, which excites the ultrasonic transducer 3, from. The latter changes the electrical ultrasonic vibrations into mechanical ones, which result when an acoustic contact is secured spread in its material between the surface of the ultrasonic transducer 2 and the surface of the test piece 4.

The ones from the imperfections 26 and the rear wall 2? of the test item 4 reflected elastic oscillations reach the ultrasonic transducer 3> where they are converted into electrical signals.

These signals arrive via the unit 5 for recording and processing the reflected ultrasonic vibrations at the same time to the input of the unit 6 for separating the signals from the interference and to the input of the AND element 21 of the time selector 20 Ultrasonic vibrations in the presence of interferences, the following signals are taken: the pulse signal 29 (Fig. 4, diagram b), which corresponds to the radiation moment of the ultrasonic vibrations in the material (transmission pulse) from the flaws 26 (Fig. 1) of the test object 4 reflected pulse signals JO, 31 and $ 2, and those from the rear wall 2? (Fig.l) of the test object 4 reflected pulse signals 33 and 34 (Fig. 4, diagram b).

The strobe pulse forming circuit 22 generates a pulse

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35 (Fig. 4 »Diagram c), the duration of which is equal to the time interval is, in which the mean interference power is determined, while its temporal position in the zone of the maximum Test sensitivity is selected in the defect-free area.

The strobe pulse forming circuit 22 (Fig. 1) generates the pulse 55 (Fig. 4, diagram c) at the end of the ultrasonic radiation period, by the pulse 36 (Fig. 4, diagram a) of the synchronizer 2 (IPig.l) is completed.

The strobe pulse 35 (Fig. 4, diagram g) is on the second input of the AND gate 21 (Fig.l), at the first Input faults arrive during this period, given.

The UHD member 21 is opened and leaves the disconnected Interferences (Fig. 4, diagram d) to the input of the element 16 (Fig. 1) for measuring the average interference power.

In the measuring element 16, the disturbances are converted into a DC voltage, which is the mean disturbance power in the Duration of the pulse 55 (Fig. 4, diagram c) corresponding Time interval is proportional.

This direct voltage then reaches the input of the unit 6 (FIG. 1) for separating the signals from the disturbances and the input of the test result indicator 3 15.

In the unit 6, the pulse signals 29 (Fig. 4, Diagrams e ;, 30, 31, 32, 33 and 34 in the next one The radiation period is separated from the disturbances at the level determined by the direct voltage.

The separated pulse signals 291 30, 31, 32, 33 and

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are from the output of the unit 6 (Fig. 1) to separate the signals from the interference via the video amplifier 9 to the Vertical deflection plates of the cathode ray tube 11 given, the deflection voltage being applied to the horizontal deflection plates thereof is created.

In the automatic error signaling device 12, the circuit 13 forms one under the action of the synchronizer 2 Strobe pulse, the test zone at the output of the UMD element 14 indicates.

The test result meter 15 is fixed by means of light-sound or Relay signaling the error, where it is at optimal Sensitivity caused by the DC voltage of the measuring element 16 is set out. This DC voltage determines the corresponding response threshold of the test result indicator 15th

In addition, the output signals of the test result indicator to external auxiliary information processing facilities, for example, can be output to an electronic computer system.

A similar process is repeated in each subsequent ultrasonic radiation period.

Thus takes place in the course of the test from period to period an automatic tracking of the interference level of the reflected ultrasonic vibrations takes place.

In the flawless area of the ultrasonic radiation period, the structural, reverberant and acoustic Disturbances reduced to the level of disturbances caused by other factors and thus in the formation

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the DC voltage IMMT the noise removal level best, niclit _t berücks maybe igt.

In some cases, the level of the mentioned interference components in the test zone, especially when testing Complicated products made from modern alloys significantly the level of other factors (self-noise, of the receiver and external interference) Exceed disturbances.

To increase the setting accuracy of the interference separation level is the time position of the strobe pulse 35 generated by the circuit 22 (Fig. 2) (Mg. 5> Diagram c) in contrast to the circuit according to FIG. 1 in the area of signals 29 (FIG. 5 »diagram b), 30, 31, 32, 33 and 34 in FIG Presence of interference selected.

In this specific example, this temporal position is selected in the test zone.

Here the DBD-Glled 21 (Fig. 2) leaves in the time interval, that of the duration of the pulse 35 (Fig. 5-, diagram c) corresponds to the pulse signals 32 (Fig. 5> Diagrams d) and 33 in the presence of disturbances to the inputs of the strobimpulsformierschaltung 23 (Fig. 2) and the AND-NOT gate.

The strobe pulse forming circuit 23 is set to a response threshold which corresponds to the maximum interference level D _max for the test conditions in question (FIG. 5, diagram d).

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By the action of the pulse signals 32 and 33, the circuit 23 (Pig. 2) forms strobe pulses 37 (Fig. 5 »diagram e) and 38 »their duration and temporal position of duration and temporal Position of the pulse signals 32 (Fig. 51, diagram d) and 33 corresponds to level H_.

A time selection takes place in the UIiD-NOT element 24 (FIG. 2) the interference from the signals 32 (Fig. 5 s diagram d) and 33 instead.

Get from the exit of the TJiTD-NOT gate of 24 (Fig. 2) the separated disturbances (Fig. 5j diagram f) to the input of the element 16 (Fig. 2) for measuring the mean interference power and the test process continues as described above.

With the help of Verzögrungsschaltung 25 (Fig * 3) is a compensation of the in the Strobimpulsformierschaltung 23 (Fig. 3) resulting delay of the Strobimpulse 37 (Fig "5 _S diagram e) take place, whereby the accuracy of the time selection increasing the interference of the signals , »

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Claims (6)

PATENT CLAIMS: 1. Ultrasonic method for material testing, which is in the Radiation of ultrasonic vibrations into the material, in the reception and processing of the reflected ultrasonic vibrations, in the setting of an interference separation level in the range of the maximum test sensitivity, in the separation of the signals from the interference on the selected level and in the registration of the test results consists, characterized in that the mentioned interference separation level for each ultrasonic radiation period θ equal to the mean interference power during ^ a time interval selected in the range of the maximum test sensitivity of the previous ultrasonic radiation period is set automatically. 2. Procedure according to. Claim 1, characterized in that that one if the time interval is in the range of the signals (29, 30, 31, 32, 33 and 34) in the presence of Interference is selected before setting the interference isolation level In this area a time selection of these disturbances from the signals (29, 30, 31, 32, 33 and 34) at a known maximum disturbance level (U) undertakes and after the "HÖn ^ d ^ F ^ üsge ^ sOnderteii ^ disturbances that Sets separation level. ~ ^ = ^ - = ^ .. 3. Ultrasonic materials testing device for implementing the method according to claim 1, wherein the output of a Ultrasonic generator, its input with one of the outputs 909828/0569 a synchronizer is connected to the input of an ultrasonic transducer, which acoustically with is coupled to the material to be tested, while the output of the ultrasonic transducer is electrically connected via a with a unit for recording and processing the reflected Ultrasonic vibrations in Heihe switched unit for Separation of the signals from the disturbances with the first input of a signal registration unit, the second input of which is coupled to the second output, characterized in that it an element (16) for ivies sung egg mean interference power and a time selector (20) containing an AND gate (21) and a strobe pulse forming circuit (22), whose input is connected to the third output of the synchronizer (2) and whose Output with one of the inputs of the UMD element (21) in connection stands, the other input to the output of the unit (5) for receiving and processing the reflected Ultrasonic vibration is placed while the output of the AND gate (21) electrically to the input of the element (16) for measuring the mean interference power, its output 90 9 828/0569 to the control input of the unit (6) for separating the signals from the. Malfunctions and to the third input of the signal registration unit is placed, is coupled. 4. Device according to claim 3, characterized in that that the output of the AND gate (21) to the input of the element (16) for measuring the mean Interfering power is connected directly. 5. Device according to claim 5, characterized in that that the time selector (20) also has a second St rob pulse-forming circuit (23), the input of which is applied to the output of the AND gate (21), and an AND-NOT gate (24) whose first input is electrically connected the output of the AND gate (21) is coupled and its second input to the output of the second strobe pulse forming circuit (23) is placed, while the output of the UHD-NOT element with the element (16) for measuring the middle Interfering power is related, contains. 6. Device according to claim 5 »thereby g ekennze ichnet that the time selector (20) also between the de η output of the AND gate (21) and the first Contains input of the AND-NOT gate (24) switched delay circuit (25). 909828/0569