RU194298U1 - Device for sequential non-destructive testing of the weld zone - Google Patents

Abstract

The invention relates to a welding technique, namely, devices for automated non-destructive testing of a weld zone. The preferred field of application of this technical solution is ultrasonic testing (UZK) of pipe metal products. The installation contains flaw detectors, a weld sensor, individual power drives of the converters and a controller. Converters are installed in a row. The output of the weld sensor is connected to the input of the controller. The controller outputs are connected to the control inputs of the power drives. The technical result of the utility model is to provide independent adjustment of the position of each transducer with respect to the seam line and to increase the reliability of the control of the weld zone. 2 s.p. f-ly, 6 ill.

Description

The invention relates to a welding technique, namely, devices for automated non-destructive testing of a weld zone. The preferred field of application of this technical solution is ultrasonic testing (UZK) of pipe metal products.

Production requirements for welded metal products include tolerances for the offset axis of the weld. For pipe metal products, the deviation of the weld line from the straight line in practice reaches ± 50 mm. In addition, there are designed curved welds, for example in welded pipes with spiral seams. In both of these cases, automated control of the weld zone is difficult without continuous monitoring of the seam line during the operation of flaw detection equipment and the necessary correction of the motion curve of the non-destructive testing sensor, as otherwise control errors, including skipping the defect or incorrect determination of its location, are possible .

From patent document GB1415389 A of 11.26.1975, an automatic ultrasonic (ultrasonic) flaw detector for a non-destructive ultrasonic inspection of a weld is known. The known device includes several flaw detection channels with separate flaw detectors and electronics units for processing measurement information placed on a self-propelled trolley to move along the control object. The converters are mounted on a common holder in a row. In this case, the flaw detector contains an optical, electrical or mechanical weld sensor, as well as a hydraulic actuator for horizontal adjustment of the holder position in order to follow the weld line, controlled by a controller in the form of a hydraulic actuator pressure regulator. However, due to the fact that the device contains a single power drive for horizontal adjustment of the holder position common to all ultrasonic transducers, it is not possible to independently adjust the spatial position of each flaw detector separately, which can lead to mismatch between the weld zone and the working zone of some transducers when scanning the object of control, and therefore to measurement errors. For example, if you combine the trajectory of the movement of the first along the path of the ultrasonic transducer with the line of the weld, then all subsequent transducers will move with increasing advancing the actual change in the shape of the seam line, since the transducers are rigidly connected to each other by the holder and the movement of the first of them causes an immediate movement and other converters. As a result, inspection of a weld by a known device cannot be considered reliable.

The technical problem to be solved is the approximation of the motion paths of all the flaw detectors of the device to the line shape of the longitudinal axis of the controlled weld. The technical result provided by this useful model is to increase the reliability of the sequential non-destructive testing of the weld zone.

The technical result is achieved due to the fact that the device for sequential non-destructive testing of the weld zone contains flaw detectors for non-destructive testing of the weld zone and a functional tracking unit with a weld sensor. At the same time, the functional tracking unit also includes individual power drives of flaw detectors and a controller. Moreover, flaw detectors are installed in a row, and the weld seam sensor is connected to all power drives through the controller.

In the particular case of the implementation of the utility model, the controller includes a storage device with a tracking buffer configured to store the coordinates of the weld line.

In another particular case, the functional tracking unit includes delay lines through which the power drives of the flaw detectors are connected to the controller.

The essence of the device for sequential non-destructive testing of the weld zone is illustrated by drawings, diagrams and graphs, which show, as an example, the preferred design of the ultrasonic testing machine.

FIG. 1-3: installation of ultrasonic testing, plan view and front view.

FIG. 4: electrical block diagram of a tracking unit.

FIG. 5: the installation operation algorithm in one cycle.

FIG. 6: conditional graphs of the line shape of the longitudinal axis of the weld and the trajectories of the flaw detectors of the installation.

The ultrasonic testing device contains a supporting element 1, electro-acoustic flaw detectors 2-4, an electronic unit for processing measurement information, a functional tracking unit, which includes a profiler scanner 5, a path sensor 6, individual power drives 7-9, a controller 10, guides 11 and holder 12 (Figs. 1-3).

Flaw detector 2 is designed to detect transverse defects of the test object, is made separately-combined, contains a pair of separate acoustically isolated primary electromagnetic-acoustic or piezoelectric transducers 13 and 14, the first of which is used for radiation, and the second for receiving ultrasonic waves. The working areas of the primary transducers 13, 14 form the common working area of the acoustic system of the transducer 2. The flaw detectors 3 and 4 have a similar design, include primary transducers 15, 16 and 17, 18, designed to detect longitudinal defects and delaminations, respectively, during complex non-destructive testing zones of the longitudinal weld. If it is necessary to search for defects of other types or to duplicate control, the design of the installation is supplemented by other flaw detectors, including those based on different physical effects, for example, flux-gate or eddy-current ones. To increase the reliability of control, the installation is performed with the possibility of duplication of the work of part of flaw detectors. The outputs of flaw detectors 2-4 are connected to the input of the electronic unit for processing measurement information.

Each power drive 7-9 consists of a fixed and moving parts, contains an electromechanical actuator and a position sensor of the actuator.

Flaw detectors 2-4 are structurally connected with the moving parts of the corresponding power drives 7-9. The fixed parts of the actuators 7-9 are connected to the supporting element 1.

Converters 2-4 are installed in a row so that in the normal position the centers of their working areas are projected on one straight line (Fig. 1). The distances Y ₁ , Y ₃ between the transducers 2-4 can be set in the range of 700-1000 mm and are equal to each other. These converters are installed with the possibility of mutually parallel movement along linear guides 11, mainly in one plane, parallel to the axis of the control object. In this case, the guides 11, together with the drives 7-9, perform the function of a technical means for moving flaw detectors relative to the supporting element 1 at a constant distance Z from the control object. In alternative embodiments of the technical solution, the guides 11 are curved or the transducers 2-4 are connected to the carrier 1 through a swing mechanism to ensure that the transducers 2-4 are rotated relative to the center of the pipe 19 so as to ensure a constant gap between the working surfaces of the transducers 2-4 and the outer surface pipe walls 19.

The profiler scanner 5 is a weld sensor, is an optical measuring device with a laser emitting element and a receiving video camera. The design of the scanner body of the profiler 5, the supporting element 1 and the holder 12 are selected from the location of the working area of the weld sensor on the axis of a number of flaw detectors 2-4 to enable measurement of the profile of the reinforcement bead of the weld and the adjacent heat-affected zone of the test object. The profiler scanner 5 is fixed at a distance of Y ₁ from the transducer 2. Alternatively, a detector for changing the characteristics of the magnetic field can be used as a weld sensor, however, an optical sensor is preferable because it can provide a more accurate determination of the center of the seam, and the accuracy of determining the center of the seam do not affect the temperature and geometry of the seam. In addition, the optical sensor has a larger range of surface capture, can be located at a distance from the pipe surface, which eliminates the risk of damage during inspection. Due to the location of the optical profiler scanner 5 in the front of the installation, away from the first flaw detector 2, the profiler scanner 5 is not susceptible to optical interference from liquid, steam or dust that accompany the work, for example, a piezoelectric type transducer, which increases the reliability control.

The path sensor 6 contains a tracking roller connected to a multi-turn incremental encoder. The sensor 6 is duplicated by an identical sensor located on the opposite end of the supporting element 1 to enable the control of the edge zone of the pipe 19 and increase the reliability of the device, and therefore increase the reliability of the sequential non-destructive testing of the weld zone.

The controller 10 includes a logic device, a control action generation unit for power drives 7-9, a memory device with a tracking buffer located on a common bus. The output of the profiler scanner 5 is electrically connected to the first measuring input of the controller 10 (Fig. 4). A path sensor 6 is connected to the second measuring input of the controller 10, and a backup path sensor is connected to the third measuring input. The controller 10 is configured to reduce the readings of the track sensors to one number based on the magnitude of the center distance of their followers. The outputs of the controller 10 are connected to the control inputs of the drives 7-9. Electrical connections are made by connecting cables. In addition, the controller 10 is configured to input external data, in particular, the speed V of the installation of the ultrasonic testing device relative to the pipe 19 or the readings of the path sensor when it is performed as a separate device. The controller 10 in conjunction with the sensors 5, 6 and the actuators 7-9 forms a multi-channel tracking unit.

The supporting element 1 is made in the form of a plate. An alternative implementation of this element in the form of a platform or frame is possible. The profiler scanner is rigidly connected to the supporting element 1 through the holder 12 or directly attached to this element. The guides 11, the fixed part of the actuators 7-9, the sensor 6, the controller 10 and the electronic unit for processing measurement information are connected to the supporting element 1 by means of fasteners.

All of the listed parts of the device are interconnected by assembly operations, which provide constructive unity and the implementation by this device of general functional purpose for consistent non-destructive testing of the weld zone.

The present technical solution operates automatically as follows.

The metal pipe 19 is placed in the control zone, weld up. The weld zone covers the weld itself and the adjacent heat-affected zones. The width of the weld reinforcement roller and the width of the heat-affected zones in practice are 10-35 and 50-100 mm, respectively. When the installation is pre-configured, the transducers 2-4 are placed relative to the center of the weld at a distance determined by the calculation based on the coverage of the scanning zone so as to ensure that ultrasonic vibrations emitted by one of the primary transducers can be reflected from defects in the weld zone and hit to the receiving primary converter. The mutual placement of the transducers determines their working area, which should coincide with the control zone of the weld.

The installation of ultrasonic testing is brought to the initial operating position on the edge of the pipe 19. In this case, the roller of the path sensor 6 is in close proximity to the end of the pipe 19 in close contact with the outer surface of its wall. The initial reading of the path sensor 6 is taken as the coordinate of the beginning of the pipe 19 along the longitudinal axis Y. The profiler scanner 5 is oriented towards the weld reinforcement roller, the coordinate of the profiler scanner 5 along the Y axis at the initial time is equal to the coordinate of the beginning of the pipe 19 along the same axis.

The profiler scanner 5 sends a flat laser beam to the surface of the tube 19 and registers the optical radiation reflected from the control object using a video camera. The device analyzes the surface profile from the received image and finds, taking into account the known distance of the center of the working area of the profiler scanner 5 from the bearing element 1, the coordinates of the edges and the middle of the protruding bead of the weld relative to the bearing element 1 along the transverse axis X.

After that, the flaw detection equipment is turned on and the ultrasonic testing device is progressively moved along the longitudinal axis of the pipe 19 with a given constant speed V. During operation of the device, the transducers 2-4 sequentially pass over the same section of the control object. In this case, the sensor 6 provides data on the current installation position at the monitoring object along the Y axis. After stopping the roller of the sensor 6, the coordinate of the end of the pipe 19 is determined, and up to this point, an infinitely large value is taken as the specified coordinate. In the process of movement of the pipe 19, the controller 10 checks a number of conditions and, if necessary, feeds control actions to the power drives of flaw detectors 2-4 (Fig. 5).

First, the logic device of the controller 10 verifies the fulfillment of condition (1).

Where:

Y _c - current reading of the path sensor;

Y _b - coordinate of the beginning of the pipe;

Y _e is the coordinate of the end of the pipe.

If condition (1) is true, then a pair of values контроллера X _c , Y _c 〉 characterizing the actual spatial position of the weld point of the weld is placed in the tracking buffer of controller 10, where X _c is the current coordinate of the middle of the weld along the transverse axis, and Y _c is the current reading track sensor along the longitudinal axis. In a similar way, data on the coordinates of the line of the weld in a length from the scanner profiler 5 to the last flaw detector 4 is gradually accumulated in the tracking buffer.

In the process, the controller 10 also checks the validity of the conditions (2).

Where:

Y _c - current reading of the track sensor;

Y _i is the coordinate of the flaw detector i relative to the path sensor, and i = 1, 2, ..., N, where N is the total number of flaw detectors;

Y _b - coordinate of the beginning of the pipe;

Y _e is the coordinate of the end of the pipe.

For installation with three flaw detectors 2, 3 and 4, expression (2) leads to the following set of independent inequalities:

The first inequality relates to transducer 2, the second inequality relates to transducer 3, and the third inequality relates to transducer 4. When the inequality is met with respect to the corresponding flaw detector, the controller 10 calculates a quantity ΔX ₁ characterizing the deviation of the center of the working area of this transducer from the normal position X ₀ , taken as the beginning of the X axis. For example, to calculate ΔX _{3 of the} transducer 4 (Fig. 2), first determine its coordinate Y _j as the difference between the current reading yes the path 6 and the sum of the values Y ₁ , Y ₂ and Y ₃ , then in the tracking buffer find a pair 〈X _j , Y _j 〉 by the key value Y _j and extract the value X _j , after which the difference X _j -X _{0 is} calculated and accepted her for ΔX ₃ . The set of values ΔX ₃ (t), where t is the time, characterizes the motion curve of the transducer 4. The logic device sends a command to the input of the control actions generation unit, the output signal of which is fed to the input of the power drive 9 to offset the transducer 4 by the amount ΔX ₃ with the aim of correction of the position of the axis of the center of its working area so that this axis coincides with the geometric line of the weld. Similar actions are performed with respect to converters 2 and 3.

As a result of independent control of the position of flaw detectors 2-4 by individual power drives 7-9 during the sequential non-destructive testing of the weld zone, the location of all these converters relative to the line of the weld is ensured that the paths of all flaw detectors of the device coincide with the line shape of the longitudinal axis of the controlled weld, due to which a high reliability of consistent control depleting the weld zone, even if the spatial distance between the working areas penetrant transducers greatly exceeds the amount of deviation from the desired weld seam line.

In an alternative embodiment, the installation of a multi-channel tracking node instead of a buffer contains three delay lines, for example digital. In this case, the actuators 7-9 are connected to the control actions generating unit of the controller 10 through the indicated delay lines. In the control process, ΔX is calculated for the weld at the point under the profiler scanner 5. At time t _{0, the} weld at the level of the profiler scanner 5 deviates from a straight line and takes the form of curve A (Fig. 6), and the ΔX value becomes excellent from zero. The controller 10 provides control actions to the actuators 7-9 for correcting the movement of the transducers 2-4 by the same value ΔX, but with different time delays, the values of which are calculated as the ratio of the distance between the profiler scanner 5 and the corresponding flaw detector to the known constant speed V of the installation relative to object of control. As a result, the motion path B of the transducer 2 begins to exactly repeat the shape of the longitudinal axis of the weld at time t ₁ , and the path C, D of the transducers 3, 4 at times t ₂ and t _3, respectively. Thus, each pair of primary electro-acoustic transducers will be shifted in the transverse direction at the moment when it is in the region of the change in the position of the weld. As a result, the transverse position of each transducer 2-4 at each moment of movement along the weld on the pipe 19 corresponds to the axis of the weld at this point, which ensures the coincidence of the working area of the flaw detector and the zone of the weld.

A variant of the device with a tracking buffer is preferable, since the determination of the value of the corrective movement does not depend on the speed V of the installation relative to the test object, which eliminates errors caused by the deviation of the speed V during the control from the set value and achieves the maximum possible reliability of the inspection.

Claims (3)

1. A device for sequential non-destructive testing of the weld zone, containing flaw detectors for non-destructive testing of the weld zone and a functional tracking unit with a weld sensor, characterized in that the functional tracking unit includes individual power drives of the flaw detectors and a controller, the flaw detectors being installed in row, and the weld sensor is connected to all power drives through the controller. 2. The device according to claim 1, characterized in that the controller consists of a storage device with a tracking buffer, configured to store the coordinates of the line of the weld. 3. The device according to claim 1, characterized in that the power drives of the flaw detectors of the functional unit are connected to the controller via delay lines.

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