CN116448870A

CN116448870A - Electromagnetic detection method and system for judging weld defects of nuclear engineering equipment

Info

Publication number: CN116448870A
Application number: CN202310389901.3A
Authority: CN
Inventors: 王宇欣; 高宇; 袁新安; 姚琳; 马迎兵; 郑岳山; 郭利峰; 李伟; 董安; 霍小东; 张耀春; 赵建明; 郭城湘; 梁潇茹; 刘帅; 包博宇; 张白茹
Original assignee: China University of Petroleum East China; China Nuclear Power Engineering Co Ltd
Current assignee: China University of Petroleum East China; China Nuclear Power Engineering Co Ltd
Priority date: 2023-04-12
Filing date: 2023-04-12
Publication date: 2023-07-18

Abstract

The application discloses an electromagnetic detection method and system for judging weld defects of nuclear engineering equipment. The method comprises the steps of detecting and using a non-defective area of a standard test block to obtain a reference Bx signal to carry out signal base value zeroing, detecting a designated defective area of the standard test block, determining a threshold line according to the Bx signal in the designated defective area, judging whether a weld joint to be detected, of which the first Bx signal does not exceed the threshold line, is qualified or marking the position, of which the first Bx signal exceeds the threshold line, as a suspected defective position, and detecting a suspected defective position area again to judge a false signal. According to the electromagnetic detection method for judging the weld defects of the nuclear engineering equipment, the base metal is not required to be thinned or damaged, the detection result can be obtained more conveniently, rapidly, accurately and efficiently, the characteristic signals can be distinguished, and further the accurate detection of the weld defects of the nuclear engineering equipment is realized, so that the safe and stable operation of the nuclear engineering equipment is ensured.

Description

Electromagnetic detection method and system for judging weld defects of nuclear engineering equipment

Technical Field

The application relates to the technical field of nuclear engineering, in particular to an electromagnetic detection method and system for judging weld defects of nuclear engineering equipment.

Background

With the continuous development of society, the demand for electric power energy is increasing. From the concrete application of the nuclear engineering at the present stage, the nuclear energy is taken as a clean energy source, and the ideal effect is shown in the practical application process. Reliable, stable and safe operation of nuclear fuel equipment becomes an important influencing factor for influencing whether nuclear engineering can operate efficiently in practical application. The new/spent fuel transport vessel plays an important role in the nuclear industry circulation system as an important special equipment for transporting the nuclear fuel assembly. The lifting lugs and tie lugs of the new/spent fuel transport vessel are subjected to load detection periodically (e.g., every two years) in accordance with transport vessel regulatory regulations. In addition, weld defects such as air holes, slag inclusions, undercut, unfused weld defects and the like are difficult to completely avoid in the welding process of the lifting lug and the bolt lug, and the degree of influence of the weld defects with different degrees on the weld quality is different. Therefore, in order to meet different requirements of different pressure-bearing members on the quality of the welding line, the defect degree of the welding line of the lifting lug and the bolt lug needs to be evaluated by a nondestructive testing method before and after a load test, so that the quality of the welding line is evaluated.

The current general nondestructive detection means are liquid penetration detection and magnetic powder detection. The magnetic powder detection is a method for observing defects by taking magnetic powder as a display medium. Patent CN102645485 discloses a method for magnetic powder inspection of small-sized tube seats of boiler headers, carried out by means of an open coil, comprising: magnetic powder is firstly applied around the fillet weld between the tube seat and the boiler header, then the longitudinal defect of the fillet weld is detected, then the transverse defect of the weld is detected, and the bidirectional perpendicular magnetization is formed by a coil magnetization method and an electrified magnetization method, so that the defect detection of the diagonal weld is realized. The liquid penetration test is to penetrate the surface defect of the member with a liquid having high permeability, and then to make the member show the defect. Patent CN110530767 discloses a remote automatic penetration inspection device and method for a control rod driving mechanism, the device is provided with a penetrating agent applying module, a monitoring camera and an illumination module, and penetrating agent applying operation can be carried out on omega welding seams at the lower part of the control rod driving mechanism through the penetrating agent applying module so as to realize the nondestructive inspection function of remote liquid penetration. However, the method needs polishing to remove the surface paint, which may bring thinning or damage to the base material, and the product is not easy to clean and demagnetize after detection, which is time-consuming and labor-consuming, so that the detection efficiency is low and the detection effect is poor.

Disclosure of Invention

The object of the present application is to solve the above technical problems.

To achieve the above object, a first aspect of the present application proposes an electromagnetic detection method for determining a weld defect of a nuclear engineering device, including:

step S1: detecting a defect-free area of a standard test block to obtain a reference Bx signal, and carrying out signal base value zeroing by using the reference Bx signal;

step S2: detecting a designated defect area of a standard test block, and determining a threshold line according to a Bx signal in the designated defect area;

step S3: detecting the weld joint to be detected to obtain a first Bx signal, if the first Bx signal does not exceed a threshold line, judging the weld joint to be detected to be qualified, and ending the detection; if the first Bx signal exceeds the threshold line, marking the position of the first Bx signal exceeding the threshold line on the weld to be detected as a suspected defect position, and performing step S4;

step S4: re-detecting the weld joint to be detected by taking the position of the suspected defect as a midpoint and the width of 15-25mm in front and back to obtain a second Bx signal, and if the obtained second Bx signal is a false signal, judging the weld joint to be detected as qualified and ending detection.

Further, in step S4, a second Bz signal and a second butterfly pattern are also obtained, and if the second Bx signal obtained in step S4 is not a dummy signal, step S5 is performed,

step S5: if the second Bx signal, the second Bz signal and the second butterfly graph are all complete, judging the weld joint to be detected as unqualified and ending detection; otherwise, go to step S6;

step S6: if the second Bz signal or the second butterfly graph is incomplete, and the second Bx signal does not exceed the threshold line, judging the weld joint to be detected as qualified, and ending detection; otherwise, go to step S7;

step S7: if the second Bx signal is an uncorrelated signal, recording the type of the uncorrelated signal and ending detection; otherwise, go to step S8;

step S8: if the second Bx signal is not the uncorrelated signal, judging the weld joint to be detected as unqualified and ending detection.

Further, the standard test block is manufactured by adopting the same materials and welding methods as those adopted by the nuclear engineering equipment.

Further, in step S1, 8-12 reference Bx signals are acquired and averaged in a defect-free area to perform signal base value zeroing.

Further, in step S2, an interface of the Bx signal is framed, and two threshold lines symmetrical to the zero value are set at the interface, so that the threshold value corresponding to the two threshold lines is a, the absolute value of the maximum value or the minimum value of the Bx signal in the defect area is b, and the absolute values of a and b conform to the following relationship:

80％≤a/b≤100％；

the distance between the threshold lines is 30-40% of the interface height.

Further, step S3 includes step S3-1 and step S3-2,

step S3-1: the nuclear engineering equipment comprises two or more welding lines to be detected, all the welding lines to be detected are detected respectively to obtain pre-detection Bx signals, and if the pre-detection Bx signals of one or more welding lines to be detected do not exceed a threshold line, the corresponding welding lines to be detected are judged to be qualified; if the pre-detection Bx signal of one or more welds to be detected exceeds the threshold line, performing step S3-2;

step S3-2: and (4) re-detecting one or more welds to be detected of which the pre-detected Bx signals exceed the threshold line to obtain a first Bx signal, marking the position of the first Bx signal exceeding the threshold line on the weld to be detected as a suspected defect position, and performing step S4.

Further, the welding seam of the nuclear engineering equipment is the welding seam of the lifting lug of the nuclear engineering container.

By applying the technical scheme, at least the following technical effects are realized:

1. according to the electromagnetic detection method, by setting the threshold line, whether the height of the maximum distortion of the Bx signal at the side deviating from the zero amplitude reaches the height of the threshold line can be conveniently observed, so that the detection result can be obtained more conveniently, rapidly, accurately and efficiently.

2. The electromagnetic detection method can comprehensively, conveniently and accurately acquire the magnetic field signal generated by the base magnetic field through signal base value zeroing, thereby realizing signal base value zeroing and providing accurate data support for subsequent defect judgment.

3. According to the electromagnetic detection method, the steps of calibrating the defect position of the suspected signal appearing again and checking the defect position are added on the basis of sectionally detecting the suspected signal, so that the condition that the defect position exceeds a threshold line due to the problems of detection misoperation and the like can be prevented from being judged to be unqualified in a welding line, meanwhile, the distinction between a false signal and a defect signal can be realized, the probability of missing detection and false detection is effectively reduced, and the detection result is more reliable.

4. The electromagnetic detection method is based on characteristic signal rechecking, increases the judging flow when individual signals in the characteristic signals are incomplete, effectively reduces the probability of missing detection and false detection, ensures that the detection result is more reliable, can distinguish false signals, irrelevant signals and defect signals, and further realizes the accurate detection of defects such as weld surface pores, slag inclusion, cracks and the like of equipment for nuclear engineering.

6. Compared with magnetic powder detection, the electromagnetic detection method does not need the processes of magnetizing the detected test piece, applying magnetic powder and the like, and can enable the detection operation to be simpler and more convenient.

7. Compared with the conventional penetration detection technology, the electromagnetic detection method can detect the internal defects of the carbon steel welding seam, so that the detection accuracy is higher.

8. Compared with the ray detection technology, the electromagnetic detection method has no radiation and does not need a special time window, so that the detection efficiency is higher.

In order to achieve the above purpose, the second aspect of the application provides an electromagnetic detection system for judging the weld defects of nuclear engineering equipment, which comprises an upper computer and an electromagnetic detection probe, wherein the electromagnetic detection probe is used for detecting the weld to be detected, the upper computer is used for controlling and displaying data of the electromagnetic detection probe,

the electromagnetic detection probe comprises a probe shell, a magnetic field sensor, a probe cover and a connector, wherein the probe shell comprises supporting legs and a through groove, the bottoms of the supporting legs are provided with arc structures, the arc structures are matched with the radian of the nuclear engineering container, the magnetic field sensor is located the through groove, the probe cover is detachably connected to the top of the probe shell, and the connector is detachably connected to the top of the probe cover.

Further, connecting grooves are formed in two sides, perpendicular to the travelling direction of the electromagnetic detection probe, of the top of the probe shell, connecting protrusions are arranged at the bottom of the probe cover, and the connecting grooves are matched with the connecting protrusions to realize detachable connection of the probe cover and the probe shell.

Further, the electromagnetic detection probe further comprises a magnetic core and an excitation coil, the inside of the probe shell is provided with a long groove and four-corner grooves, the four-corner grooves are respectively arranged in the long groove and the through groove, the magnetic core is arranged in the long groove, and the excitation coil is wound on the magnetic core and is positioned in the four-corner grooves.

Further, the electromagnetic detection probe also comprises a signal processing circuit, and the signal processing circuit is arranged in the probe shell.

Further, the electromagnetic detection probe further comprises a nut and a washer, and the joint is detachably connected to the probe cover through the nut and the washer.

1. compared with magnetic powder detection, the electromagnetic detection system does not need to magnetize a detected test piece, magnetic powder is applied and other processes, so that the detection operation is simpler and more convenient.

2. Compared with the conventional penetration detection technology, the electromagnetic detection system can detect the internal defects of the carbon steel welding seam, so that the detection accuracy is higher.

3. Compared with the ray detection technology, the electromagnetic detection system has no radiation and does not need a special time window, so that the detection efficiency is higher.

4. According to the electromagnetic detection system, the arc structure of the electromagnetic detection probe is matched with the radian of the nuclear engineering container to be detected, so that the electromagnetic probe can be further attached to the welding line to be detected during detection, and the accurate detection of the welding line to be detected is realized.

5. This electromagnetic detection system sets up long groove structure and four corners groove structure through setting up electromagnetic detection probe through the cooperation, can be with electromagnetic detection probe and nuclear engineering equipment firm laminating to realize the accurate acquisition of the welding seam magnetic field signal that awaits measuring.

Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

FIG. 1 illustrates a flow chart of an electromagnetic detection method for weld defect determination for nuclear engineering equipment according to one embodiment;

FIG. 2 (a) shows a top view of a standard test block of one embodiment;

FIG. 2 (b) shows a front view of a standard block of one embodiment;

FIG. 2 (c) shows a side view of a standard test block of one embodiment;

FIG. 3 illustrates a characteristic signal diagram after Bx signal contribution to one embodiment has been zeroed;

FIG. 4 illustrates a flow chart of a first Bx signal determination for a weld under test, according to one embodiment;

FIG. 5 is a characteristic signal diagram of a Bx signal interface for detecting defects according to one embodiment;

FIG. 6 illustrates a characteristic signal plot resulting from lift-off for one embodiment;

FIG. 7 illustrates a plot of signature signals resulting from dithering for one embodiment;

FIG. 8 illustrates a graph of characteristic signals due to edge effects for one embodiment;

FIG. 9 illustrates a characteristic signal diagram of one embodiment resulting from a chassis not being powered on;

FIG. 10 illustrates a characteristic signal diagram generated by a sudden chassis outage for one embodiment;

FIG. 11 illustrates a flowchart of another embodiment electromagnetic detection method for weld defect determination for nuclear engineering equipment;

FIG. 12 illustrates a characteristic signal plot after review of the defect locations of one embodiment;

FIG. 13 shows a characteristic signal diagram of Bz signal loss in one embodiment;

FIG. 14 illustrates a diagram of a signature missing from a butterfly graph in one embodiment;

FIG. 15 illustrates a characteristic signal plot resulting from weld surface undulations of an embodiment;

FIG. 16 illustrates a graph of a characteristic signal resulting from undercut for one embodiment;

FIG. 17 illustrates a characteristic signal plot resulting from flash for one embodiment;

FIG. 18 illustrates a flowchart of an electromagnetic detection method for weld defect determination for nuclear engineering equipment, in accordance with one embodiment;

FIG. 19 shows an exploded view of an electromagnetic field detection probe of one embodiment;

FIG. 20 shows a block diagram of the bottom of an electromagnetic detection probe housing of one embodiment;

FIG. 21 shows a block diagram of the top of an electromagnetic detection probe housing of one embodiment;

FIG. 22 illustrates a block diagram of an electromagnetic detection probe cover of one embodiment;

fig. 23 shows a structural diagram of the inside of an electromagnetic detection probe housing of an embodiment.

Description of the drawings: 10. a probe housing; 101. support legs; 102. a through groove; 103. four corner grooves; 104. a long groove; 105. a connection groove; 20. a magnetic field sensor; 30. a magnetic core; 40. an exciting coil; 50. a signal processing circuit; 60. a probe cover; 601. a connection protrusion; 602. a joint hole; 70. a nut; 80. a gasket; 90. and (3) a joint.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The present application is described in further detail below in conjunction with specific embodiments, which should not be construed as limiting the scope of the claims.

The following describes a flowchart method and a system of an electromagnetic detection method for judging weld defects of nuclear engineering equipment according to an embodiment of the present application with reference to the accompanying drawings.

FIG. 1 is a flowchart of an electromagnetic detection method for weld defect determination for nuclear engineering equipment according to one embodiment of the present application, as shown in FIG. 1, the method comprising the steps of:

and S1, detecting a defect-free area of the standard test block to obtain a reference Bx signal, and carrying out signal base value zeroing by using the reference Bx signal.

The standard test block refers to a test block having the same material type, the same specification, the same welding method, the same automation level and other standard requirements as the tested equipment, and is shown in fig. 2 (a) -2 (c) in a specific embodiment.

Specifically, in the defect-free area of the standard test block, 8-12 reference Bx signals are collected and averaged to perform signal base value zeroing.

In one embodiment, the characteristic signals of the alternating electromagnetic field include Bx signals, bz signals, and butterfly patterns. Generally, the direction parallel to the scanning direction is defined as the X direction, the direction perpendicular to the scanning direction and parallel to the surface of the device under test is defined as the Y direction, and the direction perpendicular to the surface of the device under test is defined as the Z direction. Further, the Bx signal is defined as a magnetic field component in the X direction and is in direct proportion to the current density in the Y direction of the surface of the device to be tested; bz signal is defined as the magnetic field component in the Z direction, positive to the current deflection curvature of the X-Y plane; the butterfly graph is defined as an X-Y plane graph of the Bx signal and the Bz signal, where the X-axis is the Bz signal and the Y-axis is the Bx signal.

The Bz signal only has higher sensitivity to cracks and larger round holes, and the Bx signal has higher detection sensitivity to the round holes and the cracks, so that the Bx signal is selected to provide more comprehensive and accurate data support for subsequent electromagnetic signal processing and defect judgment.

In addition, for the alternating current magnetic field detection technology, a magnetic field signal acquired by a Bx signal is composed of a base magnetic field and a disturbance magnetic field caused by a defect. As shown in fig. 3, by collecting the first 10 magnetic field signals in the defect-free area of the standard test block weld, and subtracting the average value of the first ten data from the data collected later, the Bx signal generated by the base magnetic field can be eliminated, the Bx signal can be zeroed, so as to obtain the Bx signal generated by the disturbance magnetic field, and the error can be further reduced by taking the average value.

Through the process, the magnetic field signal generated by the base magnetic field can be comprehensively, conveniently and accurately obtained, so that the signal base value is zeroed, and accurate data support is provided for subsequent defect judgment.

And S2, detecting a designated defect area of the standard test block, and determining a threshold line according to a Bx signal in the designated defect area.

Specifically, an interface of the Bx signal is framed, two threshold lines symmetrical to a zero value are set at the interface, so that the threshold value corresponding to the two threshold lines is a, the absolute value of the maximum value or the minimum value of the Bx signal in the defect area is b, and the a and the b meet the following relation: a/b is more than or equal to 80% and less than or equal to 100%. Meanwhile, the distance between the threshold lines accounts for 30-40% of the interface height.

In one embodiment, the threshold line range may be set by setting a/b=100%, so that the greater of the maximum value or the minimum value of the Bx signal matching the standard block defect region can be corresponded.

In one embodiment, first, bx signal distortion values specifying defects in a standard test block are obtained. The specified defect is a defect type and a defect size, and is preset based on past data and personnel experience. And then, the Bx signal interface is framed in a certain range, so that the height of the maximum distortion of the Bx signal, which deviates from one side of the zero amplitude, is not less than 15% of the height of the Bx signal interface, two threshold lines are symmetrically arranged on the upper side and the lower side of the zero amplitude, and the height of a region clamped by the two threshold lines accounts for 30% of the height of the Bx signal interface.

In the above process, after the Bx signal generated by the base magnetic field is zeroed in step S1, the distortion of the Bx signal caused by the defect can be more intuitively displayed in a visual manner by framing the interface and setting the threshold line, so that the worker can more clearly, quickly, conveniently and accurately identify the defect, and in addition, the ratio of the distance between the threshold lines to the height of the interface is set to be not less than 30%, so that the defect can be effectively prevented from being missed.

Step S3, detecting a weld joint to be detected to obtain a first Bx signal, if the first Bx signal does not exceed a threshold line, judging the weld joint to be detected to be qualified, and ending the detection; if the first Bx signal exceeds the threshold line, marking the position of the first Bx signal exceeding the threshold line on the weld to be detected as a suspected defect position, and performing step S4.

In one embodiment, as shown in fig. 4, step S3 specifically includes the following steps:

and step S3-1, if the nuclear engineering equipment comprises two or more weld joints to be detected, respectively detecting all the weld joints to be detected, and sequentially obtaining pre-detection Bx signals. If the pre-detection Bx signal of one or more welds to be detected does not exceed the threshold line, the corresponding welds to be detected are judged to be qualified. If the pre-detection Bx signal of one or more welds to be detected exceeds the threshold line, step S3-2 is performed.

And S3-2, re-detecting one or more welds to be detected of which the pre-detection Bx signals exceed the threshold line to obtain a first Bx signal, marking the positions of the first Bx signals exceeding the threshold line on the welds to be detected as suspected defect positions, and performing step S4.

In one embodiment, after calibration of the standard test block is completed, detection of each segment is completed in sequence according to intermittent weld joints of the nuclear engineering equipment, and detection data and results of each segment are stored. And if the deformation of the Bx signal detected by the whole section does not exceed the threshold line, judging that the welding line is qualified. When the distortion of the Bx signal exceeds a threshold line, a characteristic signal diagram shown in fig. 5 appears, and the scanning is continued at a constant speed until the detection of the segmentation is completed. Then, a next step of determination is performed, including: and (3) keeping the detection parameters of the alternating-current electromagnetic field unchanged, and precisely scanning the segments with suspected signals (namely the first Bx signals) according to the same speed and the same scanning direction. When the suspected defect signal (namely the second Bx signal) appears again, the scanning of the probe is stopped, and the suspected defect position is marked.

Because a certain error can be generated when the signal is abnormal through a manual judgment mode, the process detects the weld to be detected, carries out fine scanning on the suspected signal again to calibrate the defect position where the suspected signal appears again so as to carry out subsequent rechecking detection, does not directly judge that the weld to be detected is unqualified, can avoid judging the condition that the weld to be detected exceeds a threshold line due to the problems of detection misoperation and the like as the weld is unqualified, can avoid missing detection by adding a certain distance before and after, effectively reduces the probability of missing detection and false detection, ensures that the detection result is more reliable, is beneficial to further judging the defect condition and the category aiming at the defect position, and provides data analysis support for solving the problem of welding operation and improving the welding technology.

And S4, re-detecting the weld joint to be detected by taking the suspected defect position as a midpoint and a width of 15-25mm before and after the suspected defect position to obtain a second Bx signal, and judging the weld joint to be detected as qualified and ending detection if the obtained second Bx signal is a false signal.

In one embodiment, the weld area is scanned with the suspected defect as a midline, and each of the anterior and posterior increases of 20mm to review the location of the defect. And if the signal is a false signal in rechecking, judging that the welding line area is qualified.

As shown in fig. 6-10, the pseudo signals include characteristic signals that the Bx signal distortion exceeds a threshold line due to non-to-be-measured weld quality problems such as lift-off, jitter, edge effect, and the like, and abnormal characteristic signals caused by the case not being powered on and the case suddenly powering off.

According to the process, the false signal and the defect signal can be distinguished by rechecking and detecting the defect position, so that the probability of missing detection and false detection is effectively reduced, and the detection result is more reliable.

In another embodiment, as shown in fig. 11, if the second Bx signal obtained in step S4 is not a dummy signal, the method further includes the following steps:

step S5: if the second Bx signal, the second Bz signal and the second butterfly graph are all complete, judging the weld joint to be detected as unqualified and ending detection; otherwise, step S6 is performed.

In one embodiment, if the characteristic signal diagram shown in fig. 12 is obtained after 20mm of the weld joint area is scanned before and after the step S4, and the second Bx signal, the second Bz signal and the second butterfly diagram in the diagram are all complete, the weld joint to be detected is judged to be unqualified, and the detection is finished.

Step S6: if the second Bz signal or the second butterfly graph is incomplete, and the second Bx signal does not exceed the threshold line, judging the weld joint to be detected as qualified, and ending detection; otherwise, step S7 is performed.

In one embodiment, a Bz signal missing feature signal is shown in fig. 13, and a butterfly signal missing feature signal is shown in fig. 14.

in one embodiment, as shown in fig. 15-17, the uncorrelated signal refers to a characteristic signal that the Bx signal distortion exceeds a threshold line due to problems of surface relief, undercut, flash, etc. of the weld being inspected.

On the basis of characteristic signal rechecking, the process increases the judging flow when individual signals in the characteristic signals are incomplete, effectively reduces the probability of missed detection and false detection, ensures more reliable detection results, realizes the distinction of false signals, irrelevant signals and defect signals, and provides data analysis support for solving the problems of welding operation and improving the welding technology.

It is worth noting that the nuclear engineering equipment weld may be the weld of the lifting lug of the nuclear engineering container.

In one embodiment, as shown in fig. 2 (a) -2 (c), a standard test block containing circular hole defects with diameters of 2mm and 1mm in the weld is taken as an example, and a circular hole defect with a minimum defect alarm size of 1mm in diameter is set.

As shown in fig. 18, the method specifically comprises the following steps:

and S101, calibrating a standard test block.

Specifically, calibration of a standard test block is performed first, an alternating current electromagnetic field detection probe is placed in a weld defect-free area of the standard test block, the first ten numbers are collected, and the average value of the first ten data is subtracted from data collected later, so that the return to zero of a Bx signal basic value is achieved, and a characteristic signal is shown in fig. 3.

Step S102, setting a threshold line.

Specifically, an alternating current electromagnetic field detection probe is scanned at a constant speed along a welding line of a standard test block, and the distortion of a 1mm diameter round hole defect Bx signal in the standard test block is obtained. The Bx signal interface is framed in the range of-50 to +50, so that the height of the maximum distortion of the Bx signal at the side deviating from the zero amplitude is not less than 15% of the height of the Bx signal interface, two threshold lines are symmetrically arranged above and below the zero amplitude, and the height of a region clamped by the two threshold lines accounts for 30% of the height of the Bx signal interface.

Step S103, segment detection.

Specifically, after calibration of the standard test block is completed, detection of each segment is completed in sequence according to intermittent weld joints of the lifting lugs. And if the deformation of the Bx signal detected by the whole section does not exceed the threshold line, judging that the welding line is qualified. When the distortion of the Bx signal exceeds a threshold line, the scanning is continued at a constant speed until the detection of the segment is completed, as shown in fig. 5, and then the next step of judgment is performed.

Step S104, accurate scanning.

Specifically, the detection parameters of the alternating current electromagnetic field are kept unchanged, and the segments with suspected signals are accurately scanned according to the same speed and the same scanning direction. And when the suspected defect signal appears again, stopping scanning of the probe, and marking the suspected defect position.

Step S105, checking detection.

Specifically, the suspected defect is taken as a central line, and the welding seam area of the strip is scanned by increasing 20mm before and after each line so as to recheck the position of the defect. If the signal is false during rechecking, as shown in fig. 6-10, the weld area is judged to be qualified. If the complete Bx signal, bz signal and butterfly graph appear in the rechecking process and the positions are consistent, as shown in fig. 12, the weld joint area is judged to be unqualified.

In step S106, the uncorrelated signal is determined.

Specifically, if the Bz signal or the butterfly pattern is missing in the review detection signal, as shown in fig. 13 and 14, it should be first observed whether the Bx signal distortion exceeds the threshold line. If the welding line area is not exceeded, the welding line area is judged to be qualified. If so, checking whether the signal is an uncorrelated signal. If the signal is not the irrelevant signal, the weld joint area is judged to be unqualified. If the signal is an uncorrelated signal, as shown in fig. 15-17, the type of uncorrelated signal is recorded.

Through the embodiment, the detection result can be obtained more conveniently, rapidly, accurately and efficiently, the false signal, the uncorrelated signal and the defect signal can be distinguished, and further, the defects such as air holes, slag inclusion and cracks on the surface of a welding line of the equipment for nuclear engineering are accurately detected, so that data analysis support is provided for solving the problem of welding operation and improving the welding technology, and further, the safe and stable operation of the nuclear engineering equipment is ensured.

In order to achieve the above embodiment, the application further provides an electromagnetic detection system for judging the weld defect of the nuclear engineering equipment, which comprises an upper computer and an electromagnetic detection probe. The electromagnetic detection probe is used for detecting the weld joint to be detected, and the upper computer is used for controlling and displaying data of the electromagnetic detection probe.

In the present embodiment, as shown in fig. 19 and 20, the electromagnetic detection probe includes a probe case 10, a magnetic field sensor 20, a probe cover 60, and a joint 90. The probe shell 10 comprises a supporting leg 101 and a through groove 102, wherein the bottom of the supporting leg 101 is provided with an arc structure, the arc structure is matched with the radian of the nuclear engineering container, and therefore the electromagnetic probe can be attached to a welding line to be detected during detection, and accurate detection of the welding line to be detected is achieved. In addition, the magnetic field sensor 20 is located in the through slot 102 for rapidly acquiring and transmitting a magnetic field signal at the weld to be measured. In addition, the probe cover 60 is detachably coupled to the top of the probe case 10, and the joint 90 is detachably coupled to the top of the probe cover 60, thereby enabling flexible installation and removal of individual components.

Further, in this embodiment, as shown in fig. 21 and 22, connecting grooves 105 are formed on two sides of the top of the probe case 10 perpendicular to the traveling direction of the electromagnetic detection probe, connecting protrusions 601 are formed on the bottom of the probe cover 60, and the connecting grooves 105 cooperate with the connecting protrusions 601 to realize detachable connection of the probe cover 60 and the probe case 10.

Further, in the present embodiment, as shown in fig. 23, the electromagnetic detection probe further includes a magnetic core 30, an excitation coil 40. In addition, the probe shell 10 is internally provided with a long groove 104 and four quadrangle grooves 103, and the quadrangle grooves 103 are respectively arranged in the long groove 104 and the through groove 102. The magnetic core 30 is disposed in the long groove 104, and the exciting coil 40 is wound around the magnetic core 30 and is positioned in the quadrangular groove 103. Therefore, the electromagnetic detection probe can be firmly attached to the nuclear engineering equipment, and the accurate acquisition of the magnetic field signal of the weld joint to be detected is realized.

Further, as shown in fig. 19, the electromagnetic detection probe further includes a signal processing circuit 50, and the signal processing circuit 50 is provided in the probe case 10.

Further, as shown in fig. 19, the electromagnetic detecting probe further includes a nut 70 and a washer 80, and a joint 90 is detachably connected to the probe cover 60 through the nut 70 and the washer 80. As shown in fig. 22, a joint hole 602 is further provided in the middle of the probe cover 60, and the joint hole 602 is fixed on the probe cover 60, so that the joint 90 can be connected with the probe cover 60 through the nut 70, the washer 80 and the joint hole 602.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.

It should be noted that in the description of the present specification, descriptions of terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Claims

1. An electromagnetic detection method for judging weld defects of nuclear engineering equipment is characterized by comprising the following steps:

step S2: detecting a designated defect area of the standard test block, and determining a threshold line according to a Bx signal in the designated defect area;

step S3: detecting a weld joint to be detected to obtain a first Bx signal, if the first Bx signal does not exceed the threshold line, judging the weld joint to be detected to be qualified, and ending the detection; if the first Bx signal exceeds the threshold line, marking the position of the first Bx signal exceeding the threshold line on the weld to be detected as a suspected defect position, and performing step S4;

2. The method according to claim 1, wherein in the step S4, a second Bz signal and a second butterfly pattern are also obtained, and if the second Bx signal obtained in the step S4 is not a dummy signal, step S5 is performed,

step S6: if the second Bz signal or the second butterfly diagram is incomplete, and the second Bx signal does not exceed the threshold line, judging the weld joint to be detected as qualified, and ending detection; otherwise, go to step S7;

step S8: if the second Bx signal is not an uncorrelated signal, judging the weld joint to be detected as unqualified and ending detection.

3. The method of claim 2, wherein the standard test block comprises the same material and welding method as the nuclear engineering equipment.

4. A method according to claim 3, wherein, in step S1,

and in the non-defect area, 8-12 reference Bx signals are acquired and averaged to carry out signal base value zeroing.

5. The method according to claim 4, wherein, in said step S2,

an interface of a Bx signal is framed, two threshold lines symmetrical to a zero value are arranged on the interface, so that a threshold value corresponding to the two threshold lines is a, the absolute value of the maximum value or the minimum value of the Bx signal of the defect area is b, and the a and the b conform to the following relation:

80％≤a/b≤100％；

the distance between the threshold lines accounts for 30-40% of the height of the interface.

6. The method of claim 4, wherein the step S3 comprises a step S3-1 and a step S3-2,

step S3-1: the nuclear engineering equipment comprises two or more than two welding lines to be detected, all the welding lines to be detected are detected respectively to obtain pre-detection Bx signals, and if the pre-detection Bx signals of one or more than one welding line to be detected do not exceed the threshold line, the corresponding welding lines to be detected are judged to be qualified; if the pre-detection Bx signal of one or more weld joints to be detected exceeds the threshold line, performing step S3-2;

step S3-2: and (4) re-detecting one or more welds to be detected of which the pre-detection Bx signals exceed the threshold line to obtain a first Bx signal, and marking the position of the first Bx signal exceeding the threshold line on the weld to be detected as a suspected defect position, wherein the position is used as a step S4.

7. The method of any of claims 1-5, wherein the nuclear engineering plant weld is a weld of a lifting lug of a nuclear engineering container.

8. An electromagnetic detection system for judging weld defects of nuclear engineering equipment is characterized by comprising an upper computer and an electromagnetic detection probe, wherein the electromagnetic detection probe is used for detecting a weld to be detected, the upper computer is used for controlling and displaying data of the electromagnetic detection probe,

the electromagnetic detection probe comprises a probe shell (10), a magnetic field sensor (20), a probe cover (60) and a joint (90), wherein the probe shell (10) comprises supporting legs (101) and a through groove (102), the bottoms of the supporting legs (101) are provided with arc structures, the arc structures are matched with the radian of the nuclear engineering container, the magnetic field sensor (20) is located in the through groove (102), the probe cover (60) is detachably connected to the top of the probe shell (10), and the joint (90) is detachably connected to the top of the probe cover (60).

9. The system according to claim 8, wherein connecting grooves (105) are formed in two sides, perpendicular to the traveling direction of the electromagnetic detection probe, of the top of the probe shell (10), connecting protrusions (601) are formed in the bottom of the probe cover (60), and the connecting grooves (105) are matched with the connecting protrusions (601) to achieve detachable connection of the probe cover (60) and the probe shell (10).

10. The system of claim 8, wherein the electromagnetic detection probe further comprises a magnetic core (30) and an excitation coil (40), a long groove (104) and four-corner grooves (103) are formed in the probe shell (10), the four-corner grooves (103) are formed in the long groove (104) and the through groove (102), the magnetic core (30) is arranged in the long groove (104), and the excitation coil (40) is wound on the magnetic core (30) and is located in the four-corner grooves (103).

11. The system of claim 8, wherein the electromagnetic detection probe further comprises a signal processing circuit (50), the signal processing circuit (50) being disposed in the probe housing (10).

12. The system of claim 8, wherein the electromagnetic detection probe further comprises a nut (70) and a washer (80), the fitting (90) being removably coupled to the probe cover (60) by the nut (70) and washer (80).