RU2351925C1 - Method of automated nondestructive quality check of pipes and device for its realisation - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: in the presence of ultrasonic contact with pipe the echo-pulse signals reflected from flaws are accepted by transformers located along the pipe, converse to codes which are selected on temporary parameters, parameter of amplitude (phase), and are logically summarised and compared to rejection measure, thus in the course of the control simultaneously traversal and dilatational ultrasonic oscillations and eddy current (magnetic) oscillations are radiated.

EFFECT: increase of informativeness and reliability of results of pipes control.

8 cl, 11 dwg

Description

The invention relates to non-destructive testing methods and means that implement the immersion echo-pulse defectoscopy method, and can be used to control the quality (body continuity and pipe wall thickness) of seamless steel pipes in production lines at pipe plants and before operation.

The pulse echo method of ultrasonic flaw detection is widely known (Shreiber D.S. Ultrasonic flaw detection. M: Metallurgy, 1965, pp. 171-173), based on sending short pulses of elastic vibrations to the controlled product, amplification and recording of the intensity and time of arrival of the echo Signals reflected from defects. By moving the transducer along the surface of the product and observing the picture on the screen of the flaw detector, it is possible to monitor the products for defects and determine their coordinates.

Known ultrasonic echo-method (method) of control (Non-destructive testing and diagnostics. Reference. VV Klyuev, FR Sosnin, VN Filippov and others. Edited by VV Klyuev. - M.: Mechanical Engineering , 1995, p.154, 172), which consists in the emission of pulses of ultrasonic vibrations, the reception and registration of echoes reflected from defects.

Such methods and devices that implement them (Passy S.Kh., Chegorinskaya ON, Shumila LN Information on the main means of ultrasonic non-destructive testing of mass production. Defectoscopy, 1984, No. 8, p. 93) are used to control pipe quality.

The disadvantages of these methods is the relatively low productivity, reliability and reliability of control.

The closest in technical essence to the proposed method of control (prototype) is the ultrasonic method of control of products and materials, RF patent No. 2179313, G01N 29/04, BIPM No. 4, 02/10/2002. Control by this method is carried out by the echo method and consists in scanning the ultrasound transducer along the product profile, registering the amplitudes and coordinates of the echo signals, processing the data on a computer, receiving two-dimensional ultrasound images during B and C scanning, summing up into one image, when the presence of a defect, all ultrasound images of this group are scanned, by which the size of the defect is estimated.

Accepted by a known method, the defect signals are converted into images that are displayed by the flaw detector. Human participation in decision making reduces the reliability of the control process due to the possibility of subjective errors. When using the known method for pipe control in continuous production, the degree of control automation is not high enough.

When receiving random interference signals, it is necessary to view all the images in the group and if the information is ambiguous, re-check the products in order to exclude their re-processing, therefore the method is not sufficiently noise-resistant and, as a result, is not reliable enough.

During pipe inspection, the following types of defects are possible: on the external and internal surfaces of the pipe (foams, sunsets, longitudinal and transverse cracks); subsurface (metal stratification); exit of wall thickness beyond tolerance. Obtaining this information is necessary for making a decision about the possibility of repairing defective pipes or translating them into inappropriate products.

When using the known method for controlling the quality of pipes in a stream, it is not possible to automatically, in the process of monitoring a moving pipe, select defects by their types, i.e. the known method is not sufficiently informative and reliable.

One of the main criteria of the procedure of immersion ultrasonic testing in dynamic mode (when the transducer or control object is moving) is the presence of acoustic contact between the transducer and the controlled product.

The known method does not take this factor into account, which, when monitoring pipes, can lead to the omission of defects in case of violation of acoustic contact (for example, when the transducer or object of control is skewed) and ultimately to a decrease in the reliability of control.

Known automated device for ultrasonic pipe quality control, RF patent No. 2209426, G01N 29/04, BIPM No. 21, 07.27.2003, which implements the known echo control method. It contains a control mechanism, consisting of a base, a bracket, on the free end of which a spring-loaded immersion bath is installed, connected by a spring-loaded telescopic rod with the axis of attachment of the bracket, the latter is connected to the lifting unit of the immersion bath, the opposite side of the immersion bath is connected through the guides to the guide frame, on the guides cams with inserts are installed, electro-acoustic transducers (EAP) of flaw detectors and thickness gauge are installed in the immersion bath, information The outputs of the flaw detectors and the thickness gauge are connected to the inputs of the adapter, the outputs of which through the coprocessor are connected to the computer and through the control unit with the lifting unit of the immersion bath and actuators.

A disadvantage of the known device is the inability to select defects according to their types, insufficient information content, lack of control of the presence of acoustic contact, insufficient reliability of the control results.

The aim of the invention (method and device) is to obtain the following technical result: increasing the information content, reliability and reliability of pipe inspection results.

This technical result is achieved by the fact that in the method of automated non-destructive testing of pipe quality, which consists in the emission of ultrasonic pulsed transducers by transducers, reception, amplification and registration of reflected echo-pulse oscillations in the presence of acoustic contact with the pipe and reflected echo-pulse signals from defects, the latter are accepted transducers located along the pipe are converted into codes that are selected by time parameters, amplitude (phase) parameter, logically ummiruyutsya and compared with the acceptance criteria, and the process control are emitted simultaneously longitudinal and transverse ultrasonic vibrations and eddy current (magnetic) oscillations.

When controlling the thickness (delamination) of the pipe wall by longitudinal ultrasonic vibrations, gates synchronized by surface pulses are formed in the time interval between the surface and bottom pulses; if there are defect signals in the time interval between gates, these signals are compared with the rejection criterion; if the latter is exceeded, the defect signals are summed and exceeding the permissible number of defect signals, a reject signal is generated.

The proposed method is implemented by a device for automated non-destructive quality control of pipes, containing a control mechanism consisting of a base, a bracket, a spring-loaded immersion bath mounted on the free end of the tub, connected by a spring-loaded telescopic rod to the bracket mounting axis, the latter is connected to the immersion bath lift assembly, the opposite side of the immersion bath through the guides it is connected to the guide frame, cams with inserts are installed on the guides, in immersion Acoustic transducers are installed in the bathtub, the outputs of which are connected to the inputs of the flaw detector and thickness gauge blocks, the information outputs of the flaw detector, thickness gauge and pipe presence sensors are connected to the adapter inputs, the outputs of which are connected to the computer through the controller and through the control unit with the immersion bath lifting unit and actuators , in the immersion bath are installed cassettes of electro-acoustic transducers of multichannel flaw detector units and thickness gauge, above the controlled pipe opposite the immersion bath, eddy current (magnetic) transducers are installed in a spring-loaded in the vertical plane and connected to the frame frame with stops, which is connected in the horizontal plane by another spring-loaded rod with a frame fixed on the axis to the control mechanism body, the outputs of the cassettes of electroacoustic and eddy current (magnetic) transducers connected to multi-channel blocks of an ultrasonic flaw detector, thickness gauge and eddy current (magnetic) flaw detector.

где Р - шаг контроля, L - ширина одного элемента преобразователя.Electro-acoustic and eddy current (magnetic) transducers are made in the form of cassettes, each of which consists of N elements, while

where P is the control step, L is the width of one element of the Converter.

The cassette of electro-acoustic transducers for controlling wall thickness and delaminations is placed parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe.

Cassettes of electro-acoustic transducers for detecting longitudinal defects are placed symmetrically at angles (10-20) ° to the horizontal diametrical plane of the pipe.

Cassettes of electro-acoustic transducers for detecting transverse defects are placed symmetrically and radially to the pipe surface at angles (30-45) ° to the vertical diametrical plane of the pipe.

The cassette of eddy current (magnetic) transducers is placed on top of the controlled pipe parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe.

Comparative analysis with the prototype shows that the claimed method and device have significant distinguishing features and meets the criterion of novelty. The joint use in the proposed method and device of known and distinctive features allows you to get a new technical result, which consists in increasing the reliability and reliability of the results of pipe inspection.

On figa shows a sounding circuit of the controlled pipe by transverse ultrasonic vibrations to detect longitudinal external defects, on figb - time chart.

On figa shows a sounding circuit of the controlled pipe by transverse ultrasonic vibrations to detect longitudinal internal defects, on fig 2b is a timing chart.

Figure 3 shows the timing diagram of the signals when monitoring bundles in a controlled pipe.

Figure 4 shows the electrical structural diagram for implementing the proposed method and device.

Figure 5, 6, 7 shows the control mechanism, front view, top, side, respectively.

On Fig is a diagram of the location of the cassettes of the transducers in the immersion bath, top view.

Figure 9 shows the layout of the cassettes of the transducers, side view.

Figure 10, 11 shows samples of the printout of the protocols of the results of ultrasonic and eddy current inspection of the pipe, respectively.

The method of automated non-destructive quality control of pipes is as follows. Transverse and longitudinal ultrasonic vibrations and eddy-current (or magnetic) vibrations are simultaneously emitted into the moving tube. In the presence of an acoustic contact, signals from defects are received by the corresponding transducers, amplified, and converted into codes. The criterion for the presence of acoustic contact is the presence of bottom pulses in the channels of the thickness gauge block. The presence of an acoustic contact is displayed on the computer monitor. Codes from defect signals of a multichannel ultrasonic flaw detector are selected by time parameters - defects are classified as external or internal.

Temporary selection is as follows. When emitting ultrasonic vibrations, using the reflected signal from the external and internal longitudinal artificial defects P (Fig. 1a, 2a) on the reference tube, during the setup process, the temporary position of the gates C1, C3 (Fig. 1b, 2b) is set so that the signal from the external artificial defect Dn was near the gate C3 on the left side (Fig.1b), the signal from the internal artificial defect was near the gate C1 on the right side (Fig.2b). Gate C2 is set in the middle of the time interval between gates C1, C3. In pipe inspection, defect signals located in the C1-C3 time interval are classified as external, defect signals located in the C1-C2 interval are classified as internal. Depending on the priority of the classification of defects (external or internal), when setting, the strobe C2 can be shifted left or right. The described principle of temporary selection is the same when detecting longitudinal and transverse defects.

Temporary selection for the control of delamination in the pipe is as follows. When longitudinal ultrasonic vibrations are emitted, pulses are formed in the tube reflected from the outer surface (Fig. 3, surface impulse P) and the inner surface (Fig. 3, bottom impulse D). In the presence of a surface pulse, gates C1, C2 are formed synchronously with it (Fig. 3) with a delay equal to t ₁ = C1-P, t ₂ = C2-P. The delay time is adjustable. When more signals of rejection criterion B appear between the gates C1, C2, the summation of these signals is performed, and when the number of signals P exceeds the allowable value K, the reject signal is generated. The summation is made if the signals P appear during the next consecutive K probing pulses. The permissible number of signals K is determined by the allowable standards for pipes with the defect area. The thickness tolerances are set at time intervals t _1p = C1-P, t _2p = D-C2.

Codes from defect signals of the eddy current flaw detector are logically summed

where C is the output signal of the defect;

H _i - the presence of a signal of heterogeneity on the pipe in the i-th channel;

M = 2 ... N - the number of adjacent channels from which the summation of the signals;

N is the total number of working channels.

Signal processing can be performed according to the parameters of amplitude or phase. Defect signals in adjacent M channels should be summed provided that they appear simultaneously, or with a temporary shift of signals between the first and last of the M channels, not more than T.

Time T is determined by the geometric location of the length of the defect in relation to the longitudinal axis of the pipe, the area of the defect and is formed by the corresponding gates.

The structural diagram of a device that implements the proposed method is shown in Fig.4. The proposed device contains a control mechanism 1, in which there is an immersion bath 2 with cassettes of electroacoustic transducers (EAP) 3 of a multichannel unit of an ultrasonic flaw detector 4 and a cassette of an EAP 5 of a multichannel unit of an ultrasonic thickness gauge 6. Above the controlled tube in mechanism 7 is an eddy current transducer 8 of a multichannel eddy current flaw detector 9. The outputs of the blocks of a multichannel ultrasonic flaw detector 4, thickness gauge 6, eddy current flaw detector 9 through an adapter 10 and cont the scooter 11 is connected to the computer 12. Other inputs of the adapter 10 are connected to the outputs of the sensors for the presence of the pipe 13, 14. The outputs of the adapter 10 are also connected to the control unit 15, the outputs of which are connected to the actuators 16, with the lifting unit 17 of the immersion bath 2, with the lowering unit 18 eddy current transducer mechanism 7.

The control mechanism 1 (FIGS. 5, 6, 7) consists of a base 19, on which an arm 21 is mounted on the axis 20. An immersion bath 2 is mounted on it on spring fingers 22. On one side, the immersion bath 2 is connected via an spring rod 23 to the axis 20. On the opposite side, the immersion bath 2 is connected through the guides 24 to the guide frame 25. Cams 26 are installed on the guide 24 with guide inserts 27 made of wear-resistant material along which the controlled pipe 28 moves. The lower part of the bracket 21 is connected to the lifting unit ma 17 immersion bath 2.

In the immersion bath 2 mounted on ball bearings:

- cassettes combined EAA 3a, 3b (Fig. 8), the outputs of which are connected to the inputs of the multi-channel block of an ultrasonic flaw detector 4;

- cassettes combined EAP 5 (Fig.8), the outputs of which are connected to the inputs of the multichannel unit of the ultrasonic thickness gauge 6.

A cassette of eddy current transducers 8 (Fig. 8) is installed above the pipe in the housing 29, the outputs of which are connected to the multichannel eddy current flaw detector 9. The housing 29 is connected to stops 30 on which inserts 31 of wear-resistant material are mounted. The housing 29 through spring fingers 32 is connected to the frame 33, which is attached to the rack 35 on the axis 34. A counterweight 36 is installed at the end of the rack 35. The housing 29 is connected through the other spring rod 37 to the axis 40, which is located on the frame 33. The rear of the frame 33 connected by the lowering unit 18 of the mechanism 7 of the eddy current transducer 8. Thus, the mechanism 7 consists of a housing 29, stops 30, frame 33.

5, 6, 7, the immersion bath 2 is shown in the raised position, the eddy current transducer mechanism 7 is in the lowered position.

EAP and eddy current transducers are made in the form of cassettes consisting of N elements. The number of cartridge elements is determined by the expression:

where P is the control step;

L is the width of one element of the Converter.

то будет контролироваться менее 100% площади трубы, что может привести к пропуску дефектов.If

less than 100% of the pipe area will be controlled, which may lead to the omission of defects.

EAP cassette 5 (Fig.9) control the wall thickness and delamination of the pipe is placed parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe.

EAP cassettes 3a (Fig.9) for the detection of longitudinal defects are placed at angles β = (10-20) ° to the horizontal diametrical plane of the pipe. The values of the angles β are selected from the condition for the optimal formation of transverse ultrasonic waves (oscillations) in the pipe body. With decreasing angle β less than 10 °, longitudinal waves will form in the pipe body, with increasing angle β more than 20 ° surface waves will form in the pipe body, which will lead to disruption of the control process.

EAP cassettes 3b (Fig. 9) for detecting transverse defects are placed radially to the pipe surface at angles α = (30-45) ° to the vertical diametrical plane of the pipe. The values of the angles α are selected from the condition of optimal placement of the EAP 3b cassettes in the immersion bath 2. The angle α less than 30 ° is prevented by the location of the EAP 3a cassettes. If the angle α is increased above 45 °, the functioning of the EAP 3b cassettes will be affected by the surface of the water filling the immersion bath 2, which will lead to disruption of the control process. The EAP of the cartridge 3b emits ultrasonic vibrations at an angle of (10-20) ° relative to the longitudinal axis of the controlled pipe to create shear waves in the pipe body.

The cassette of the eddy current transducer 8 (Fig.9) is placed on top of the controlled pipe parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe.

The device operates as follows. The control mechanism 1 is installed in the production line. In the initial position, the immersion bath 2 is in the lower position, the eddy current transducer mechanism 7 is in the upper position. Controlled pipes move at a constant speed in the production line along the rolling table translationally-rotationally. When the front end of the pipe approaches the sensor 13, the latter generates the corresponding signal through the adapter 10 and the controller 11 in the computer 12, where the countdown of time t ₁ begins before the signal from the sensor 14 arrives. The sensors 13 and 14 are located at a fixed distance L, the value of which is stored in the memory Computer 12. After the signal from the sensor 14, the computer 12 calculates the speed of the pipe, which is necessary to measure the length of the pipe and the location of the defects.

After the signal from the sensor 14 appears after a time t ₂ necessary for the front end of the moving pipe to reach the edge of the immersion bath 2 far in the direction of the pipe, the controller 11 through the adapter 10 and the control unit 15 issues a command to the lifting unit 17 of the immersion bath 2 and lowering unit 18 the mechanism 7 of the eddy current transducer 8. The bracket 21 rises and presses the immersion bath 2 to the pipe 28. The frame 33 lowers and presses the housing 29 with the eddy current transducer 8 to the pipe 28. The controlled pipe 28 moves through the immersion 2 nd bath semisubmerged in the water situation. EAP cassettes 3a (Fig. 8, 9) emit ultrasonic vibrations in two opposite directions around the pipe circumference, EAP cassettes 3b emit ultrasonic vibrations in two opposite directions along the pipe axis. The signals from the EAP cassettes 3, 5, the eddy current transducer 8 enter the blocks of a multichannel flaw detector 4, a thickness gauge 6 and an eddy current flaw detector 9, respectively, then to the adapter 10, where they are converted to digital form, and through the data bus enter the controller 11.

The time between the reflected surface and bottom pulses with an EAP 5 in the thickness gauge 6 is converted into a pulse duration, which is proportional to the thickness of the pipe wall. These pulses are supplied to the adapter 10, where they are converted into codes that are supplied to the controller, where the primary processing of information takes place. Information on defects in the pipe body and pipe wall thickness is highlighted. Based on the application program stored on the computer hard drive 12, digital processing of information is carried out, real-time results are displayed on the computer screen 12 and the processed information is stored in a database. Before control, the computer 12 enters the necessary initial data: date, workshop numbers, shifts, pipe lots, pipes, melts, average pipe diameter and wall thickness, operating mode, display scale of information on the monitor, digital filtering coefficients, repetition of defects, thickness tolerances pipe walls.

After the rear end of the monitored pipe passes the sensor for the presence of pipe 14, after time t from the adapter 10 through the control unit 15, a command is issued to the lifting unit 17 of the immersion bath 2 and lowering unit 18 of the mechanism 7, by which the immersion bath 2 is lowered, and the mechanism 7 rises. As the next pipe approaches, the control process repeats.

If there is a defect in the pipe body or the pipe wall thickness falls outside the tolerance field in the controller 11, the corresponding codes are generated, which enter the adapter 10, where they are converted into the corresponding commands, which are transmitted to the actuators 16 through the control unit 15. The latter mark the rejected places with paint on a controlled pipe and include a pipe ejector in the scrap pocket. Information about each monitored pipe is recorded in the computer database 12. An appropriate monitoring protocol is printed out for each pipe.

The proposed device is manufactured and tested in pipe rolling workshops of OJSC "Taganrog Metallurgical Plant". As EAP 3 cassettes of a flaw detector, combined piezoelectric four-channel transducers with a width of 10 mm and a length of 25 mm each were used. As a cartridge 5 thickness gauge used combined piezoelectric eight-channel transducers of a cylindrical shape with a diameter of 10 mm

As units of a flaw detector 4, a thickness gauge 6, an eddy current flaw detector 9, electronic components were used: generators of clock pulses, radio pulses, receiving and amplifying paths made on transistors and microcircuits. The adapter 10 and controller 11 are made in the form of nodes on microcircuits. The control unit 15 represents a set of thyristors for generating control commands. Actuators 16 are paint strippers and pneumatic cylinders for controlling pipe ejectors.

The device was tested on several batches of pipes 12 m long, with a diameter from 73 mm to 273 mm with three-shift operation of the production line. Figure 10, 11 shows samples of the printout of the results of ultrasonic and eddy current control of a reference pipe with three longitudinal external artificial defects, one internal longitudinal defect and thinning in the middle of the pipe.

The test results confirmed the information content, reliability and reliability of pipe quality control of the proposed device.

Claims (8)

1. A method of automated non-destructive quality control of pipes, which consists in the emission of ultrasonic pulsed transducers by transducers, reception, amplification and registration of reflected echo-pulse oscillations, characterized in that in the presence of acoustic contact with the pipe and reflected echo-pulse signals from defects, the latter are received by the transducers, located along the pipe, are converted into codes that are selected by time parameters, the amplitude (phase) parameter, are logically summed and compared the acceptance criteria, the process control are emitted simultaneously longitudinal and transverse ultrasonic vibrations and eddy current (magnetic) oscillations. 2. The method according to claim 1, characterized in that when controlling the thickness (delamination) of the pipe wall by longitudinal ultrasonic vibrations, gates synchronized by surface pulses are formed in the time interval between the surface and bottom pulses, if there are defect signals in the time interval between the gates, these signals are compared with defective criterion, if the latter is exceeded, the defect signals are summed and if the allowable number of defect signals is exceeded, the defect signal is generated. 3. A device for automated non-destructive quality control of pipes, comprising a control mechanism consisting of a base, an arm, on the free end of which a spring-loaded immersion bath is installed, connected by a spring-loaded telescopic link to the axis of attachment of the arm, the latter is connected to the lifting unit of the immersion bath, the opposite side of the immersion bath through the guides are connected to the guide frame, cams with inserts are installed on the guides, electroacoustic elements are installed in the immersion bath sound transducers, the outputs of which are connected to the inputs of the flaw detector and thickness gauge blocks, the information outputs of the flaw detector, thickness gauge and pipe presence sensors are connected to the adapter inputs, the outputs of which are connected to the computer through the controller and through the control unit with the immersion bath lifting unit and actuators, characterized in that in the immersion bath are installed cassettes of electro-acoustic transducers of multichannel flaw detector units and thickness gauge, above the controlled pipe opposite and eddy current (magnetic) transducers are installed in the mercer bath in a vertically spring-loaded and connected to the frame frame with stops, which is connected in the horizontal plane by another spring-loaded rod with a frame mounted on an axis to the control mechanism housing, the outputs of the electroacoustic and eddy-current (magnetic) transducers are connected with multichannel units of an ultrasonic flaw detector, thickness gauge and eddy current (magnetic) flaw detector. 4. The device according to claim 3, characterized in that the electroacoustic and eddy current (magnetic) transducers are made in the form of cassettes, each of which consists of N elements, while

where P is the control step, L is the width of one element of the Converter. 5. The device according to claim 3, characterized in that the cassette of electro-acoustic transducers for controlling wall thickness and bundles is placed parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe. 6. The device according to claim 3, characterized in that the cassettes of electro-acoustic transducers for detecting longitudinal defects are placed symmetrically at angles of 10-20 ° to the horizontal diametrical plane of the pipe. 7. The device according to claim 3, characterized in that the cassettes of electro-acoustic transducers for detecting transverse defects are placed symmetrically and radially to the surface of the pipe at angles of 30-45 ° to the vertical diametrical plane of the pipe. 8. The device according to claim 3, characterized in that the cassette of eddy current (magnetic) transducers is placed on top of the monitored pipe parallel to the horizontal section of the pipe coaxially with the vertical diametrical plane of the pipe.

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