A magnetic particle detector connection assembly and a magnetic particle detection device

Abstract

The present invention discloses a magnetic particle detector connection assembly and a magnetic particle detection device, which relate to the technical field of non-destructive flaw detection. The magnetic particle detector connection assembly includes: a parallel mounting rod capable of simultaneously passing through the mounting hole in the middle of the upper side of two magnetic particle detector bodies, for connecting the two magnetic particle detector bodies; a linkage portion capable of simultaneously contacting the upper ends of the start buttons on the two magnetic particle detector bodies; a connection portion, one end of which is hinged to the middle of the parallel mounting rod and the other end is fixedly connected to the parallel mounting rod, capable of parallel mounting the two magnetic particle detector bodies and ensuring the synchronization of the operation of the two magnetic particle detector bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke poles and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants. The magnetic particle detection device includes the aforementioned magnetic particle detector connection assembly and two magnetic particle detector bodies.

Description

Technical Field

[0001] The present invention relates to the technical field of non-destructive flaw detection, and in particular to a magnetic particle detector connection assembly and a magnetic particle detection device. Background Art

[0002] After removing temporary attachments that served as guides for the steel lining modules of a nuclear power plant, the removed areas required 100% penetrant or magnetic particle inspection. These attachments were primarily removed mechanically or thermally. Mechanically, an angle grinder with a 2.5mm-thick grinding wheel was used, while thermal cutting employed oxyacetylene. However, due to tool limitations, the temporary attachments would always remain at least 5mm above the parent material during cutting.

[0003] The steel lining was coated and concrete poured after the surface quality was hidden and qualified. That is, the inner side of the 6mm wall panel was fully coated with two coats of primer or paint, with a dry film thickness of about 280 microns. The concrete on the outside except for the dome has been poured. The back side of the wall panel is in an unreachable state and does not meet the conditions for initial non-destructive testing. Conventional VT (visual testing), PT (penetrant testing), and RT (radiographic testing) are no longer applicable.

[0004] Furthermore, the inventors discovered that while UT testing (ultrasonic testing) can effectively penetrate the aforementioned panels, due to the presence of the back angle steel, numerous rivets, and the concrete and other dielectric contours, normal echoes are emitted from all locations, making it difficult to effectively distinguish and display the back echo, making it impossible to effectively judge the scanning echo. Furthermore, the yoke penetration depth of existing magnetic particle detectors is only 4-4.5mm, making it incapable of detecting defects on the outer wall of a 6mm panel. Summary of the Invention

[0005] In response to the technical problem that existing non-destructive testing devices are unable to effectively detect the above-mentioned steel lining wall panels, the present invention provides a magnetic particle detector connection assembly and a magnetic particle detection device, which can install two magnetic particle detector bodies together and ensure the synchronization of the operation of the two magnetic particle detector bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke poles and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0006] The present invention is achieved through the following technical solutions:

[0007] In the first aspect, the present invention provides a magnetic particle detector connection assembly, comprising: a parallel mounting rod, which can simultaneously pass through the mounting holes in the middle of the upper sides of two magnetic particle detector bodies, and is used to connect the two magnetic particle detector bodies; a linkage part, which can simultaneously abut against the upper ends of the start buttons on the two magnetic particle detector bodies; a connecting part, one end of which is hinged to the middle of the parallel mounting rod, and the other end is fixedly connected to the linkage part.

[0008] Before nondestructive testing (NDT), the steel-lined panels of existing nuclear power plants are already covered with a protective layer on the inside and concrete poured on the outside. Conventional visual inspection, penetrant testing, and radiographic testing are no longer applicable. Furthermore, due to the presence of angle steel, rivets, and concrete on the outside of the panels, ultrasonic NDT is unable to detect defects. Furthermore, the magnetic field penetration depth of the yoke of existing magnetic particle detectors is only 4-4.5 mm (the maximum achievable depth under current technical conditions), making it impossible to detect defects on the outer wall of a 6 mm panel.

[0009] However, non-destructive testing of defects in the steel lining panels of nuclear power plants is imminent, and people have been eager to be able to perform effective non-destructive testing on them. To this end, the inventor adopted the method of increasing the magnetic field strength of a single magnetic particle detector. Although this increased the penetration depth of its magnetic field yoke, the operation was extremely unstable and it was very easy to burn the magnetic particle detector, resulting in the inability to conduct non-destructive testing normally. However, due to the structure of the nuclear power plant, most of the wall panels are relatively high, and the internal operating space available for non-destructive testing is small. If a larger magnetic field generator is used for testing, it is difficult to ensure the temperature of the magnetic particle detector, which not only affects the accuracy of the test results, but also easily bumps and damages the wall panel surface. Therefore, the technical problem of being unable to perform effective non-destructive testing on the steel lining wall panels of the nuclear power plant in this state has long plagued the builders of the nuclear power plant.

[0010] After being stuck for a long time, the inventor tried to use two magnetic particle detectors to work together. However, when the two magnetic particle detectors were working, the synthetic magnetic flux was extremely unstable and fluctuated. The reason was that it was impossible to ensure that the two magnetic particle detectors generated magnetic fields synchronously.

[0011] Therefore, the magnetic particle detector connection assembly provided by the present application, the mounting rod can simultaneously pass through the mounting hole in the middle of the upper side of the two magnetic particle detector bodies, so that the two magnetic particle detector bodies of the same specifications can be fixed together in parallel (with the same magnetic field direction) through the mounting rod, so that the ends of the two magnetic particle detector bodies are on the same plane, and the linkage part can simultaneously contact the upper ends of the start buttons on the two magnetic particle detector bodies. One end of the connecting part is hinged to the middle of the mounting rod, and the other end is fixedly connected to the linkage part, so that when the linkage part is pressed down, the two magnetic particle detector bodies mounted in parallel by the mounting rod can be started at the same time, which can ensure the synchronization of the operation of the two magnetic particle detector bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke pole, and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0012] In an optional embodiment, the assembling rod fixes the two magnetic particle detector bodies through a threaded connection, so as to facilitate the rapid assembly of the two magnetic particle detector bodies.

[0013] In an optional embodiment, one end of the parallel mounting rod is provided with an end cap and the other end is threadedly connected with a fastening nut, further ensuring the quickness of parallel mounting of the two magnetic particle detector bodies.

[0014] In an optional embodiment, the linkage part is in the shape of a flat plate, so as to simplify the structural shape of the linkage part and facilitate processing while ensuring that the linkage part can press down the start buttons of two magnetic particle detector bodies at the same time.

[0015] In an optional embodiment, a connecting ring is provided at one end of the connecting portion, and the connecting ring is movably sleeved on the middle part of the parallel mounting rod to ensure that the connecting portion can rotate freely relative to the parallel mounting rod.

[0016] In an optional embodiment, two connecting parts are provided at intervals to ensure the stability of the linkage part during the pressing process, and further improve the synchronization of the movements of the two magnetic particle detector bodies.

[0017] In an optional embodiment, the connecting portion includes an arc segment and an oblique rod segment connected in sequence, the arc segment is connected to the parallel rod, and the oblique rod segment is connected to the linkage portion, so that when the start buttons of the two magnetic particle detector bodies are pressed down, the linkage portion always exerts a force downward.

[0018] In an optional embodiment, the oblique rod section is tilted downward along the length direction of the connecting portion to ensure that the linkage portion and the start buttons of the two magnetic particle detector bodies can fit well in an unactivated state.

[0019] In an optional embodiment, along the length direction of the parallel rod, the oblique rod section is inclined toward the corresponding end of the parallel rod, further improving the smoothness of the linkage movement and preventing the linkage from tilting toward one end when pressed down.

[0020] In the second aspect, the present invention provides a magnetic particle detection device, including the above-mentioned magnetic particle detector connection assembly and two magnetic particle detector bodies; the parallel mounting rod passes through the mounting hole in the middle of the upper side of the magnetic particle detector body, and fixes the two magnetic particle detector bodies in parallel; the linkage part simultaneously contacts the upper ends of the start buttons on the two magnetic particle detector bodies under the action of its own weight.

[0021] The magnetic particle inspection device provided by the present invention has two magnetic particle inspection instrument bodies of the same specifications fixed together in parallel at the same working position, so that the ends of the two magnetic particle inspection instrument bodies are on the same plane, and the linkage portion can simultaneously abut the upper ends of the start buttons on the two magnetic particle inspection instrument bodies. One end of the connecting portion is hinged to the middle part of the parallel mounting rod, and the other end is fixedly connected to the linkage portion. When the linkage portion is pressed down, the two magnetic particle inspection instrument bodies connected by the parallel mounting rod can be simultaneously started (with the magnetic field directions being consistent), which can ensure the synchronization of the operation of the two magnetic particle inspection instrument bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke pole and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects

[0023] 1. The magnetic particle detector connection assembly provided by the present invention has a parallel mounting rod that can simultaneously pass through the mounting hole in the middle of the upper side of two magnetic particle detector bodies, so that two magnetic particle detector bodies of the same specification can be fixed together in parallel through the parallel mounting rod, so that the ends of the two magnetic particle detector bodies are on the same plane, and the linkage part can simultaneously abut the upper ends of the start buttons on the two magnetic particle detector bodies. One end of the connecting part is hinged to the middle of the parallel mounting rod, and the other end is fixedly connected to the linkage part, so that when the linkage part is pressed down, the two magnetic particle detector bodies connected by the parallel mounting rod can be started simultaneously, which can ensure the synchronization of the operation of the two magnetic particle detector bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke pole and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0024] 2. In the magnetic particle inspection device provided by the present invention, two magnetic particle inspection instrument bodies of the same specifications are fixed together in parallel at the same working position, so that the ends of the two magnetic particle inspection instrument bodies are on the same plane, and the linkage part can simultaneously abut the upper ends of the start buttons on the two magnetic particle inspection instrument bodies. One end of the connecting part is hinged to the middle part of the parallel mounting rod, and the other end is fixedly connected to the linkage part, so that when the linkage part is pressed down, the two magnetic particle inspection instrument bodies installed in parallel by the parallel mounting rod can be started simultaneously, which can ensure the synchronization of the operation of the two magnetic particle inspection instrument bodies, thereby enhancing the local magnetic flux of the electromagnetic yoke pole and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0026] In the attached figure:

[0027] Figure 1 This is a structural diagram of a connection assembly of a magnetic particle detector according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic side structural diagram of a connecting portion according to an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the structure of a magnetic particle detection device according to an embodiment of the present invention;

[0030] Figure 4 This is a diagram of the original state of the surface crack of the front crack test block after welding according to an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of a simulated test piece without coating and the penetration depth of the magnetic field of a DC electromagnetic yoke according to an embodiment of the present invention;

[0032] Figure 6 Schematic diagram of a coating simulation test piece showing the depth of magnetic field penetration of a DC electromagnetic yoke according to an embodiment of the present invention;

[0033] Figure 7 This is a diagram showing the results of penetration testing of a front crack test block according to an embodiment of the present invention;

[0034] Figure 8 This is a diagram showing the results of magnetic particle testing of cracks on a front crack test block according to an embodiment of the present invention;

[0035] Figure 9 This is a diagram of the state of the front crack test block after sandblasting treatment in an embodiment of the present invention;

[0036] Figure 10 This is a diagram showing the results of a penetration test on a front crack test block after sandblasting according to an embodiment of the present invention;

[0037] Figure 11 This is a diagram showing the magnetic particle inspection results of a front crack test block after sandblasting treatment according to an embodiment of the present invention;

[0038] Figure 12 This is a diagram showing the magnetic particle inspection results of a front crack test block after sandblasting and paint coating according to an embodiment of the present invention;

[0039] Figure 13 This is a magnetic trace diagram of a low-sensitivity test piece detected by magnetic particle inspection according to an embodiment of the present invention;

[0040] Figure 14 This is a magnetic trace diagram of the sensitivity test piece detected by magnetic particle inspection in an embodiment of the present invention;

[0041] Figure 15 This is a magnetic trace diagram of a high-sensitivity test piece detected by magnetic particle inspection according to an embodiment of the present invention;

[0042] Figure 16 This is a diagram showing the magnetization test results of a coated DC electromagnetic yoke with a grooved back surface of a test block according to an embodiment of the present invention;

[0043] Figure 17 This is a magnetic trace pattern obtained by magnetic particle testing of a back-grooved test block arranged at 5, 6, and 7 mm from the steel plate surface according to an embodiment of the present invention;

[0044] Figure 18 This is a magnetic trace image of the groove detection on the back of the 6mm steel lining wall panel according to the embodiment of the present invention;

[0045] Figure 19 The size of the test block is intended to verify the embodiment of the present invention;

[0046] Figure 20 The magnetic particle detection device of the embodiment of the present invention is Figure 19 Schematic diagram of the results of magnetic particle testing on the test block shown.

[0047] Markings and corresponding parts names in the accompanying drawings:

[0048] 10-magnetic particle detector body, 20-parallel mounting rod, 21-end cap, 22-fastening nut, 30-linkage part, 40-connecting part, 41-connecting ring, 42-arc segment, 43-oblique rod segment. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0051] In the description of the embodiments of the present application, the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] Example 1

[0053] Combine Figure 1 This embodiment provides a magnetic particle detector connection assembly, including: a parallel mounting rod 20, which can simultaneously pass through the mounting holes in the middle of the upper sides of the two magnetic particle detector bodies 10, and is used to connect the two magnetic particle detector bodies 10 ( Figure 3 ); the linkage portion 30 can simultaneously abut against the upper ends of the start buttons on the two magnetic particle detector bodies 10; the connecting portion 40, one end of which is hinged to the middle of the parallel mounting rod 20, and the other end is fixedly connected to the linkage portion 20.

[0054] Typically, the assembling rod 20 secures the two magnetic particle detector bodies 10 via a threaded connection, facilitating quick assembly of the two magnetic particle detector bodies 10. The threaded connection between the assembling rod 20 and the magnetic particle detector body 10 can be achieved by providing threaded ends at both ends of the assembling rod 20 and fitting corresponding nuts, or by directly connecting the assembling rod 20 to the magnetic particle detector body 10.

[0055] In this embodiment, one end of the assembling rod 20 is provided with an end cap 21 and the other end is threadedly connected to a fastening nut 22. During installation, it is only necessary to insert the rod portion of the assembling rod 20 into the corresponding mounting holes on the two magnetic particle detector bodies 10 (the bolt mounting holes on the magnetic particle detector bodies 10) and then tighten the fastening nut 22, thereby further ensuring the quick installation of the two magnetic particle detector bodies 10.

[0056] Continue to combine Figure 1 The linkage part 30 is in the shape of a flat plate, so as to simplify the structural shape of the linkage part 30 while ensuring that the linkage part 30 can press the start buttons of the two magnetic particle detector bodies 10 at the same time, and facilitate processing.

[0057] Combine Figure 2 A connecting ring 41 is provided at one end of the connecting portion 40 , and the connecting ring 41 is movably sleeved on the middle of the parallel mounting rod 20 to ensure that the connecting portion 40 can rotate freely relative to the parallel mounting rod 20 .

[0058] It is understandable that two connecting parts 40 are provided at intervals to ensure the stability of the linkage part 30 during the pressing process, and further improve the synchronization of the actions of the two magnetic particle detector bodies 10.

[0059] Continue to combine Figure 2 Specifically, the connecting portion 40 includes an arc segment 42 and an oblique rod segment 43 connected in sequence. The arc segment 42 is connected to the parallel rod 20, and the oblique rod segment 43 is connected to the linkage portion 30, so that when the start buttons of the two magnetic particle detector bodies 10 are pressed down, the linkage portion 30 always exerts a downward force.

[0060] Preferably, along the length direction of the connecting portion 40, the oblique rod section 43 is inclined downward to ensure that the linkage portion 30 and the start buttons of the two magnetic particle detector bodies 10 can fit well in the unactivated state.

[0061] Preferably, the oblique rod section 43 is inclined toward the corresponding end of the assembling rod 20 along the length of the assembling rod 20, further improving the smoothness of the movement of the linkage portion 30 and preventing the linkage portion 30 from tilting toward one end when pressed downward. In other words, the distance between the ends of the two connecting portions 40 connected to the linkage portion 30 is greater than the distance between the ends of the two connecting portions 40 connected to the assembling rod 20.

[0062] It should be noted that before non-destructive testing of the steel lining panels of existing nuclear power plants, the inner side of the panels has been covered with a protective layer and the outer side has been poured with concrete. Commonly used visual inspection, penetration testing and radiographic testing are no longer applicable. At the same time, due to the presence of angle steel, rivets and concrete on the outer side of the panels, ultrasonic non-destructive testing cannot detect defects. The magnetic field penetration depth of the yoke of the existing magnetic particle detector is only 4 to 4.5 mm (the maximum detection depth achievable under existing technical conditions), which cannot detect defects on the outer wall of the 6 mm panel.

[0063] However, non-destructive testing of defects in the steel lining panels of nuclear power plants is imminent, and people have been eager to be able to perform effective non-destructive testing on them. To this end, the inventor adopted the method of increasing the magnetic field strength of a single magnetic particle detector. Although this increased the penetration depth of its magnetic field yoke, the operation was extremely unstable and it was very easy to burn the magnetic particle detector, resulting in the inability to conduct non-destructive testing normally. However, due to the structure of the nuclear power plant, most of the wall panels are relatively high, and the internal operating space available for non-destructive testing is small. If a larger magnetic field generator is used for testing, it is difficult to ensure the temperature of the magnetic particle detector, which not only affects the accuracy of the test results, but also easily bumps and damages the wall panel surface. Therefore, the technical problem of being unable to perform effective non-destructive testing on the steel lining wall panels of the nuclear power plant in this state has long plagued the builders of the nuclear power plant.

[0064] After being stuck for a long time, the inventor tried to use two magnetic particle detectors to work together. However, when the two magnetic particle detectors were working, the synthetic magnetic flux was extremely unstable and fluctuated. The reason was that it was impossible to ensure that the two magnetic particle detectors generated magnetic fields synchronously.

[0065] Therefore, combined Figure 3 In the magnetic particle detector connection assembly provided in this embodiment, the assembling rod 20 can simultaneously pass through the mounting hole in the middle portion of the upper side of two magnetic particle detector bodies 10, so that two magnetic particle detector bodies 10 of the same specification can be fixed together in parallel at the same working position through the assembling rod 20 (the connection should ensure that the magnetic field direction is consistent), so that the ends of the two magnetic particle detector bodies 10 are on the same plane, and the linkage portion 30 can simultaneously abut the upper ends of the start buttons on the two magnetic particle detector bodies 10. One end of the connecting portion 40 is hinged to the middle portion of the assembling rod 20, and the other end is fixedly connected to the linkage portion 30. When the linkage portion 30 is pressed downward, the two magnetic particle detector bodies 10 connected by the assembling rod 20 can be simultaneously started, which can ensure the synchronization of the operation of the two magnetic particle detector bodies 10, thereby enhancing the local magnetic flux of the electromagnetic yoke pole and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0066] Example 2

[0067] Combine Figure 3 This embodiment provides a magnetic particle inspection device, comprising the magnetic particle detector connection assembly described in Example 1 and two magnetic particle detector bodies 10. The parallel mounting rod 20 passes through the mounting hole in the middle of the upper side of the magnetic particle detector bodies 10 and securely connects the two magnetic particle detector bodies 10 in parallel (the connection should ensure that the magnetic field directions are consistent). The linkage portion 30, under its own weight, simultaneously abuts against the upper ends of the start buttons on the two magnetic particle detector bodies 10. In this embodiment, the magnetic particle detector bodies 10 are DC magnetic yokes.

[0068] In addition, the verification steps of the magnetic particle detection device provided in this embodiment include:

[0069] S10. Preparation of simulated specimens.

[0070] Specifically, the simulated specimens were made from Q265HR steel plate, the same material as the steel lining, and were divided into two types: front-side cracked specimens and back-side grooved specimens.

[0071] The front crack test block was a comparative test block made to verify whether the known open crack defects in the simulated test piece can be effectively detected when the paint thickness on the inner side of the steel lining wall exceeds the standard requirement of 0.05mm. In this embodiment, the simulated test piece has a size of 370×270×10mm. A weld was welded in the middle of the test plate using the same welding process as the on-site steel lining. A crack was formed in the weld. The original state of the surface crack after welding is as follows: Figure 4 shown.

[0072] The purpose of the back-grooved test block is to verify the effective penetration depth of the magnetic field when the DC electromagnetic yoke is used to magnetize from the inside of the steel lining wall panel, and to identify the effective magnetic traces formed by the back-side machined grooves.

[0073] The DC electromagnetic yoke magnetic field penetrates the simulated specimen. In this embodiment, the simulated specimen has a size of 200x45x17mm. The test block is uncoated ( Figure 5 ) and coated ( Figure 6 ) in two forms, with the bottom of the groove being 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, and 8mm from the steel plate surface respectively. They are mainly used to test the effective penetration depth of the magnetic field after the DC electromagnetic yoke is electrified;

[0074] A simulated specimen with a 6mm steel lining and grooved wall panel was used. In this embodiment, the specimen had specifications of 500×100×6mm (the wall thickness of the simulated specimen was measured at three points and was 6.08mm, 6.13mm, and 6.07mm, with an average thickness of 6.09mm). One side of the front of the specimen was painted consistent with the on-site painting process, while the other side was sandblasted after the paint was removed to compare the effect of the paint coating on the magnetic particle testing results of the DC electromagnetic yoke. The back of the specimen was machined with grooves, with a spacing of 30mm between each groove and a groove depth of 2mm, 1.5mm, 1.3mm, 0.8mm, and 0.5mm, respectively.

[0075] S20. Verification of sensitivity of AC electromagnetic powder test on the inner wall of the paint coating of the front crack test block.

[0076] Specifically, it includes the following sub-steps:

[0077] S21. Perform non-destructive testing on the front crack test piece before spraying paint.

[0078] After the front crack test block is completed, the surface inspection methods required by the standard (NB / T20002.6-2013, Chapter 7.2.6) are used to inspect the front crack simulation specimens respectively by penetration and magnetic particle inspection to determine the inspection results of the simulated crack on the surface of the tested specimen under the original state.

[0079] Defects on the test blocks were confirmed using penetrant testing. This was primarily to confirm the location, shape, and size of the cracks on the front cracked test blocks, and to compare them with subsequent magnetic traces in the coated and uncoated states. Solvent-removal dye penetrant testing was used, and the penetrant testing process parameters are shown in Table 1.

[0080]

[0081] Table 1

[0082] Combine Figure 7 After imaging, a crack with a length of 43 mm is formed, and its position, shape and size are consistent with its original state.

[0083] In this state, magnetic particle testing was performed on the front crack specimen to verify the consistency between the magnetic traces of the simulated crack and the defects revealed by the penetrant testing. The magnetic particle testing process parameters are shown in Table 2.

[0084]

[0085] Table 2

[0086] Combined with the actual working conditions on site, the test block was magnetized by the portable AC electromagnetic yoke wet continuous method. The simulated crack magnetic traces showed as follows: Figure 8 As shown. Figure 7 and Figure 8 It can be determined that the position and length of the magnetic traces of the known crack defects here are consistent with the cracks formed by the penetration test.

[0087] S22. Verify the sandblasting process status of the front crack test block before coating.

[0088] In order to simulate the actual process of steel lining 6mm wall panel, the surface of the front crack test block was sandblasted using the workshop sandblasting process. The state of the test block after sandblasting is as follows Figure 9 shown.

[0089] Since the sandblasting process will cause the sealing and closing of open defects on the surface of the test block, in order to verify the actual state of the known crack defects of the front crack test block after sandblasting, it is necessary to conduct penetrant testing on the front crack test block after sandblasting to confirm the changes of the known crack defects. The same penetrant testing process (Table 1) was used to conduct penetrant testing on the simulated test piece after sandblasting, and the same magnetic particle testing process (Table 2) was used to conduct magnetic particle testing. The penetrant test results show that Figure 10 As shown, magnetic traces are shown as Figure 11 shown.

[0090] The inspection results show that for known crack defects treated by sandblasting, the penetrant inspection can no longer form an effective crack defect image display, while the magnetic particle inspection can still obtain the same magnetic trace display as before sandblasting, thereby effectively detecting the known simulated crack defect at that location.

[0091] S23. Prepare a paint coating on the front crack test piece.

[0092] Specifically, the front crack test block was painted using the same coating process as the steel lining. The painting process was strictly carried out in accordance with the painting process of the physical construction of the steel lining, which was two layers of primer plus one layer of topcoat.

[0093] The paint thickness of the steel-lined siding was measured, revealing a maximum thickness of approximately 280µm. To verify the effectiveness of magnetic particle inspection when coated, the paint applied to the front crack test piece was thicker than the paint thickness measured on the siding. After the paint process, the front crack test piece was measured using a coating thickness gauge at nine points along the edges of known crack defects. The measured values were all greater than 300µm, exceeding the actual paint coating thickness on the steel-lined siding.

[0094] S24. Conduct magnetic particle inspection on the front crack test piece with coating.

[0095] Combine Figure 12 After the test block was painted, the same magnetic particle inspection process (Table 2) was used to detect the known crack defects of the front crack test block, and clear magnetic traces were still obtained. The position and size were consistent with the previous test results, which proved the feasibility and effectiveness of the magnetic particle inspection method for the current coating thickness and coated state of the steel lining wall panel.

[0096] S25. Test the sensitivity of the coated magnetic particle test on the front crack test piece.

[0097] Attach low, medium and high sensitivity sensors at regular intervals to the remaining material of the steel lining wall panels, and use the same painting process as the steel lining wall panels to spray and dry the paint coating.

[0098] A DURLSCOPE coating thickness gauge was placed directly above pre-mapped high-, medium-, and low-sensitivity test strips to measure coating thickness. The coating thicknesses at the three sensitivity test strips were 308, 382, and 382 microns, exceeding the actual maximum thickness of 280 microns measured for the steel lining panel. Magnetization tests were then conducted using a portable electromagnetic yoke, alternating current, and wet continuous methods to verify that the magnetization sensitivity under these conditions met the magnetic trace indication requirements for the medium-sensitivity standard test strip specified in the NB / T20003 standard.

[0099] Combine Figure 13-15The low-sensitivity test piece (A1: 60 / 100 microns) shows the clearest magnetic traces. The medium-sensitivity test piece (A1: 30 / 100 microns) shows a fainter magnetic trace than the low-sensitivity test piece, but it can still be effectively identified. The high-sensitivity test piece (A1: 15 / 100 microns) shows a fainter magnetic trace, forming the circular grooves and vertical grooves in the magnetization direction of the standard test piece, making it difficult to discern. This means that the magnetic trace identification and verification method for magnetization inspection meets the medium sensitivity (A1: 30 / 100 microns) requirement specified in the NB / T20003.5 magnetic particle inspection standard. It can be applied to magnetic particle inspection and verification of quality on 6mm steel lining panels, where temporary attachments have been removed, while the coating is still in place.

[0100] S30. Verify the sensitivity of the coated DC electromagnetic yoke to the outer wall of the back grooved test block.

[0101] Specifically, a portable electromagnetic yoke was selected to perform wet continuous method testing and verification using direct current, and its process parameters are shown in Table 3.

[0102]

[0103] Table 3

[0104] The specific steps are:

[0105] S31. Select the back-grooved test blocks arranged at 2, 3, 4, 5, 6, 7, and 8 mm from the left side of the steel plate surface to conduct a penetration depth test to verify the electromagnetic energization of the DC electromagnetic yoke; and conduct DC electromagnetic energization on the test blocks.

[0106] The magnetization test results are as follows Figure 16 In the figure, starting from the right side, the grooves are 2, 3, 4, 5, and 6 mm, respectively, and they can all form clear and discernible effective magnetic traces in turn. Among them, the magnetic trace image at the 7 mm groove is relatively faint.

[0107] S32. Verify the depth of the DC electromagnetic yoke magnetic field penetrating into the coated simulated specimen

[0108] Specifically, a back-grooved test block arranged at 5, 6, and 7 mm from the steel plate surface was selected, and the surface was subjected to a brush coating process consistent with the steel lining wall coating. After confirming that the coating thickness of the back-grooved test block was greater than the actual measured coating thickness of the steel lining, a DC electromagnetic yoke was used to verify the penetration depth of the electromagnetic field. The test results were as follows: Figure 17Starting from the right, the 5mm and 6mm grooves each produce clear and discernible magnetic traces, while the 7mm groove shows a fainter magnetic trace. This is consistent with the magnetic trace test results of the uncoated specimen. This indicates that the DC electromagnetic yoke achieves sufficient magnetization penetration depth into 6mm thick plate, making the magnetic particle inspection method effective and feasible for verifying the quality of the temporary attachment removal area on the outer wall of the steel lining.

[0109] S33, simulate the groove on the back of the steel lining 6mm wall panel

[0110] It is understandable that in order to better fit the actual working conditions of the steel lining, the feasibility and effectiveness of the magnetic particle inspection process for the temporary attachment removal part on the outer side of the steel lining was verified by using the DC electromagnetic yoke wet continuous method, and the groove simulation specimen was made using the steel lining cutting residue.

[0111] After the sensitivity of the magnetic particle inspection system is confirmed to be correct, a contrast enhancer is applied to the uncoated area of the simulated specimen, and then the grooved simulated specimen is sprayed with magnetic suspension while being electromagnetized to obtain effective magnetic trace display. Figure 18 From the left, the corresponding grooves on the back of the wall are 2, 1.5, 1.3, 0.8, and 0.5 mm deep.

[0112] Depend on Figure 18 As can be seen, grooves with depths of 2, 1.5, 1.3, and 0.8 mm, distributed sequentially on the simulated specimen, all produce clearly discernible magnetic traces. Only the grooves at a depth of 0.5 mm produce a perceptible magnetic concentration, but the magnetic traces are less clear. This magnetization method is particularly advantageous for identifying and observing the magnetic traces displayed by DC magnetization, especially when alternating between on and off magnetization. Therefore, the skills of certified operators are highly demanding, and practice with actual measurements using the simulated specimens listed above is necessary before actual testing.

[0113] Theoretically, the reason the 0.5mm grooved area fails to produce magnetic trace aggregation and effective magnetic trace display after electromagnetization is that the groove lines are narrow and shallow at this location. This results in a small leakage magnetic field, which leads to less magnetic concentration and, consequently, difficulty in forming an effective magnetic trace display between the poles on the back side of the groove. Furthermore, due to the relatively small manufacturing characteristics of the portable electromagnetic yoke's pole coils, the magnetic field strength formed between the poles is limited during electromagnetization, and the magnetic lines of force are significantly weakened when they pass through the 6mm wall and reach the 0.5mm deep groove. These two factors combined make it difficult to form clear magnetic traces on the magnetized side of the poles.

[0114] Therefore, two electromagnetic yokes of the same model and specification were assembled together (the magnetic powder detection device provided in this embodiment), and the same magnetization process (Table 3) as in the above test process was used to test the magnetic powder detection device. Figure 19The test block shown in the figure was tested. The test block was grooved with depths of 0.2, 0.4, 0.6, 0.8 and 1 mm from the left. Before the experiment, the non-grooved surface of the test block was painted in the same way as the steel lining. The wall thickness values of the test block corresponding to the three grooves of 0.2mm, 0.4mm and 0.6mm were measured to be 6.83mm, 6.83mm and 6.87mm respectively. Then the vertical magnetic pole spacing of the magnetic particle detection device provided in the embodiment was electromagnetically energized by DC across the three grooves of 0.2mm, 0.4mm and 0.6mm and the test results were obtained as shown below. Figure 20 As shown in the figure (from the left, the 0.2, 0.4, and 0.6 mm grooves show magnetic traces). Except for the 0.2 mm groove, which shows a fainter magnetic trace (but still discernible), the 0.4 mm and 0.6 mm grooves both produce clear and discernible magnetic traces. Therefore, they can be used for nondestructive testing of 6 mm thick steel lining panels in nuclear power plants.

[0115] However, the two electromagnetic yokes are heavy when bundled together, which brings great inconvenience to the actual MT inspection operation on site. Considering that walkway boards and scaffolding are laid according to the parts to be inspected, the horizontal scaffolding above the parts to be inspected can be used as support and suspension points, and the magnetic particle inspection device provided in this embodiment can be bundled and fixed with an anti-falling rope. This can prevent the risk of falling and reduce the labor intensity of the inspection personnel's hand-held operation, ensuring the required inspection convenience and efficiency.

[0116] In summary, in the magnetic particle detection device provided by this embodiment, two magnetic particle detector bodies 10 of the same specifications are fixed together in parallel at the same working position, so that the ends of the two magnetic particle detector bodies 10 are on the same plane, and the linkage part 30 can simultaneously resist the upper ends of the start buttons on the two magnetic particle detector bodies 10. One end of the connecting part 40 is hinged to the middle part of the parallel mounting rod 20, and the other end is fixedly connected to the linkage part 30, so that when the linkage part 30 is pressed down, the two magnetic particle detector bodies 10 installed in parallel through the parallel mounting rod 20 can be started at the same time, which can ensure the synchronization of the operation of the two magnetic particle detector bodies 10, thereby enhancing the local magnetic flux of the electromagnetic yoke pole, and effectively increasing the penetration depth of the leakage magnetic field in the magnetized area to more than 6 mm, so as to effectively perform non-destructive testing on the steel lining wall panels of nuclear power plants.

[0117] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetic particle detector connection assembly, characterized in that: include: A parallel mounting rod (20) is capable of simultaneously passing through the mounting holes in the middle of the upper sides of the two magnetic particle detector bodies (10) and is used to connect the two magnetic particle detector bodies (10). One end of the parallel mounting rod (20) is provided with an end cap (21) and the other end is threadedly connected with a fastening nut (22). In the installed state, the rod portion of the parallel mounting rod (20) passes through the corresponding mounting holes on the two magnetic particle detector bodies (10) to fix the two magnetic particle detector bodies (10) in parallel. The linkage part (30) is in the shape of a flat plate and can simultaneously abut against the upper ends of the start buttons on the two magnetic particle detector bodies (10); The connecting portion (40) has one end hinged to the middle of the parallel rod (20) and the other end fixedly connected to the linkage portion (30). The connecting portion (40) comprises an arc segment (42) and an oblique rod segment (43) connected in sequence, the arc segment (42) is connected to the parallel rod (20), and the oblique rod segment (43) is connected to the linkage portion (30); In the installed state, the linkage part (30) simultaneously contacts the upper ends of the start buttons on the two magnetic particle detector bodies (10) under the action of its own weight.

2. The magnetic particle detector connection assembly according to claim 1, characterized in that: A connecting ring (41) is provided at one end of the connecting portion (40), and the connecting ring (41) is movably sleeved on the middle portion of the assembling rod (20).

3. The magnetic particle detector connection assembly according to claim 1 or 2, characterized in that: Two connecting portions (40) are arranged at intervals.

4. The magnetic particle detector connection assembly according to claim 1, characterized in that: Along the length direction of the connecting portion (40), the oblique rod section (43) is inclined downward.

5. The magnetic particle detector connection assembly according to claim 4, characterized in that: Along the length direction of the parallel rod (20), the oblique rod section (43) is arranged to be inclined toward the end portion corresponding to the parallel rod (20).

6. A magnetic particle detection device, characterized in that: It comprises a magnetic particle detector connection assembly as claimed in any one of claims 1 to 5 and two magnetic particle detector bodies (10); The parallel mounting rod (20) passes through the mounting hole in the middle of the upper side of the magnetic particle detector body (10) and fixes and connects the two magnetic particle detector bodies (10) in parallel; The linkage part (30) simultaneously contacts the upper ends of the start buttons on the two magnetic particle detector bodies (10) under the action of its own weight.

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