Device for detecting damage to coated metal substrates based on two-dimensional array magnetic field sensors and its operation method

Abstract

This invention provides a device and its operation method for detecting damage to coated metal substrates based on a two-dimensional array magnetic field sensor. The method includes setting multiple magnetic field sensors at the test site, arranging excitation coils around the sensors, and forming a two-dimensional array magnetic field sensing unit from all the sensors. The number of sensors required is determined based on the area of ​​the test site, and the sensors are placed in holes in a non-metallic substrate directly above the test site, ensuring that the effective detection surfaces of all sensors completely cover the test site. The excitation signal frequency of a multi-frequency eddy current excitation signal generator is set. This invention can acquire magnetic field data images of the test piece at different excitation frequencies over a long period, facilitating the simultaneous acquisition of damage data images of a large area at different low excitation frequencies. This significantly reduces operational difficulty and simplifies the operation steps, while also improving detection efficiency and range.

Description

Technical Field

[0001] This invention belongs to the technical field of metal damage detection instruments, specifically relating to a device for detecting damage to a coated metal substrate based on a two-dimensional array magnetic field sensor and its operating method. The coated metal substrate refers to a metal substrate with a protective coating on its surface. Background Technology

[0002] Alternating current can be used to generate eddy currents at a certain depth on the surface of a base metal material. When the base metal has cracks or corrosion damage, the eddy currents change, and the magnetic field generated by the eddy currents also changes. By using a magnetic field sensor to detect the changes in the magnetic field generated by the eddy currents, the damage condition of the base metal surface can be determined.

[0003] However, the existing magnetic field detection sensors have a very small effective detection area. In actual operation, the operator needs to control the magnetic field detection sensor to move linearly at a uniform and slow speed (usually the speed should be controlled at 1mm / s) along a preset path. This places very high demands on the operator. If the control is not stable, the detection data will be distorted. At the same time, there are problems such as low detection efficiency, cumbersome operation and high operation difficulty. Summary of the Invention

[0004] The purpose of this invention is to provide a device for detecting damage to a coated metal substrate based on a two-dimensional array magnetic field sensor and its operation method, which at least solves the technical problems of high operational difficulty and cumbersome operation process in existing metal substrate damage detection.

[0005] The technical solution adopted in this invention is as follows.

[0006] A device for detecting damage to a coated metal substrate based on a two-dimensional array magnetic field sensor includes an excitation coil and a magnetic field sensor. Multiple magnetic field sensors are arranged in an array at the part to be measured, and an excitation coil is arranged outside the magnetic field sensors. All the magnetic field sensors together constitute a two-dimensional array magnetic field sensing unit.

[0007] Preferably, the two-dimensional array magnetic field sensing unit consists of an excitation coil and multiple magnetic field detection sensors arranged in an array within the excitation coil, with the spacing between adjacent magnetic field detection sensors not exceeding 1 mm.

[0008] Preferably, the two-dimensional array magnetic field sensing unit consists of multiple excitation coils and multiple magnetic field detection sensors, with one magnetic field detection sensor arranged in each excitation coil, and the spacing between adjacent excitation coils is no more than 1 mm.

[0009] To further reduce the difficulty of operation and facilitate flexible and rapid adjustment of the effective detection area, each excitation coil is embedded in the hole edge of the non-metallic substrate. All connection lines of the excitation coil are buried in the non-metallic substrate. A step is provided on the hole edge of each non-metallic substrate and inside the excitation coil. The step is used to place the magnetic field detection sensor, and the wiring terminal that cooperates with the magnetic field detection sensor is located on the surface of the step.

[0010] Furthermore, the terminal block has a sheet-like structure, and the surface of the terminal block is flush with the surface of the stepped platform.

[0011] Furthermore, all the connection lines of the excitation coils are embedded on a non-metallic substrate to form an integrated circuit board structure.

[0012] This invention also includes a multi-frequency eddy current excitation signal generator, a magnetic field data acquisition unit, a data processing module, and a display. The multi-frequency eddy current excitation signal generator generates a multi-frequency excitation signal and forms a magnetic field at the measured location, simultaneously generating a frequency marker signal and transmitting it synchronously to the magnetic field data acquisition unit. A two-dimensional array magnetic field sensing unit detects magnetic field data at different excitation frequencies, records and extracts the magnetic field data at different excitation frequencies, and transmits the magnetic field data to the magnetic field data acquisition unit. The magnetic field data acquisition unit acquires the magnetic field data and the frequency marker signal, matches and stores the magnetic field data and the frequency marker signal, and feeds it back to the data processing module. The data processing module generates a magnetic field data graph from the read magnetic field data and outputs it.

[0013] Preferably, the multi-frequency excitation signal has a frequency of 0.05Hz-200kHz, and the multi-frequency excitation signal includes a first frequency emitted sequentially during a first millisecond time period T1, a second frequency emitted during a second millisecond time period T2, and so on, during the Kth millisecond time period T... K The Kth frequency emitted within the range has a total duration of all millisecond-level time intervals controlled within one second; the detection thickness range corresponding to the first frequency is 0-h1 mm, the detection thickness range corresponding to the second frequency is 0-h2 mm, and the detection thickness range corresponding to the Kth frequency is 0-h... K mm, 0 mm indicates the detection reference surface, h1 mm indicates the depth h below the detection reference surface. K The position of mm, h1 < h2 < h K In this invention, the multi-frequency eddy current excitation signal generator can continuously generate multiple different frequencies within a second-level time period. A programmable signal generator can be used, and these required frequency levels can be set by those skilled in the art through programming.

[0014] An operating method using the aforementioned metal substrate damage detection device includes the following steps:

[0015] Step 1: Place the non-metallic substrate with the excitation coil on the surface of the part of the metal substrate to be tested;

[0016] Step 2: Determine the number of magnetic field sensors to be placed based on the area of ​​the part to be measured, and place the magnetic field sensors in the holes of the non-metallic substrate directly above the part to be measured, ensuring that the effective detection surface of all magnetic field sensors can completely cover the part to be measured.

[0017] Step 3: Based on the material and thickness of the metal substrate being tested, set the excitation signal frequency of the multi-frequency eddy current excitation signal generator;

[0018] Step 4: Turn on the multi-frequency eddy current excitation signal generator, keep the non-metallic substrate and magnetic field detection sensor stationary for the set time, and then perform damage detection on the next part to be tested after the set time is over.

[0019] In step 2, placing the magnetic field detection sensor in the hole of the non-metallic substrate involves placing the magnetic field detection sensor stably on the surface of the stepped platform.

[0020] Beneficial effects: Compared with existing technologies, the present invention adopts a combination of two-dimensional array magnetic field sensing units and variable excitation frequency, which allows the magnetic field detection sensor to be placed directly on the sample surface. It can acquire magnetic field data images of the test piece at different excitation frequencies for a long time, eliminating the need for long-term scanning operations and multiple frequency-changing scans of linear magnetic field sensors. This facilitates the acquisition of damage data images of a large area of ​​the test site at different low excitation frequencies in one go, which not only greatly reduces the difficulty of operation and simplifies the operation steps, allowing ordinary technicians to master the operation process in a short time, but also improves detection efficiency and detection range. More importantly, it eliminates the problem of detection data distortion and improves the accuracy of detection results. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the interaction between the excitation coil and the magnetic field detection sensor of the metal substrate damage detection device in the embodiment;

[0022] Figure 2 This is a schematic cross-sectional view of the excitation coil and the magnetic field detection sensor in the embodiment.

[0023] Figure 3 This is a schematic diagram showing the disassembled state of the excitation coil and the magnetic field detection sensor in the embodiment;

[0024] Figure 4 This is a schematic diagram showing the removal of a magnetic field detection sensor from the metal substrate damage detection device in the embodiment.

[0025] Figure 5 for Figure 4Enlarged view of section G (diagram of the internal structure of the hole);

[0026] Figure 6 This is a schematic diagram of the bottom structure of the non-metallic substrate of the metal substrate damage detection device in the embodiment;

[0027] Figure 7 This is a block diagram showing the connections of various parts of the metal substrate damage detection device in the embodiment;

[0028] Figure 8 This is a schematic diagram of the damage morphology detected by the metal matrix damage detection device in the embodiment. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings. Example

[0030] Combination Figures 1 to 8 As shown, a device for detecting damage to a coated metal substrate based on a two-dimensional array magnetic field sensor includes an excitation coil 20 and magnetic field detection sensors 21. Multiple magnetic field detection sensors 21 are arranged in an array at the area to be measured. An excitation coil 20 is arranged outside the magnetic field detection sensors 21. All the magnetic field detection sensors 21 together constitute a two-dimensional array magnetic field sensing unit. Each two-dimensional array magnetic field sensing unit consists of 64*64, 128*128, 256*256, 512*512, or 1024*1024 magnetic field detection sensors 21, and this number can be flexibly adjusted according to the object being detected. The two-dimensional array magnetic field sensing unit is composed of multiple excitation coils 20 and multiple magnetic field detection sensors 21. Figure 1 The diagram only schematically shows 24 magnetic field detection sensors 21 and 24 small coils. One magnetic field detection sensor 21 is arranged in each excitation coil 20, and the distance between adjacent excitation coils 20 is no more than 1 mm.

[0031] In this embodiment, combined with Figure 2 , Figure 5 As shown, each excitation coil 20 is embedded in the hole edge portion of the non-metallic substrate 22, and the connection lines of all excitation coils 20 are buried on the non-metallic substrate 22. The connection lines of the excitation coils 20 buried on the non-metallic substrate 22 form an integrated circuit board structure. Each excitation coil 20 is provided with a holding part 25 on its top. A step 23 is provided on the hole edge of each non-metallic substrate 22 and located inside the excitation coil 20. The step 23 is used to place the magnetic field detection sensor 21. The wiring terminal 24 that cooperates with the magnetic field detection sensor 21 is located on the surface of the step 23. The wiring terminal 24 has a sheet structure and the surface of the wiring terminal 24 is flush with the surface of the step 23.

[0032] In this embodiment, combined with Figure 7As shown, the metal matrix damage detection device also includes a multi-frequency eddy current excitation signal generator, a magnetic field data acquisition unit, a data processing module, and a display. The multi-frequency eddy current excitation signal generator generates multi-frequency excitation signals and forms a magnetic field at the measured location, simultaneously generating a frequency marker signal and transmitting it to the magnetic field data acquisition unit. A two-dimensional array magnetic field sensing unit detects magnetic field data at different excitation frequencies, records and extracts the data, and transmits it to the magnetic field data acquisition unit. The magnetic field data acquisition unit acquires the magnetic field data and the frequency marker signal, matches and stores the magnetic field data and the frequency marker signal, and feeds it back to the data processing module. The data processing module generates a magnetic field data graph from the read magnetic field data and outputs it. The multi-frequency eddy current excitation signal generator can continuously generate multiple different frequencies within a second-level time period. A programmable signal generator can be used, and these required frequency levels can be set by those skilled in the art through programming. In one scheme: the multi-frequency excitation signal generated by the multi-frequency eddy current excitation signal generator includes a first frequency (40kHz) emitted in the first millisecond time period T1 (0-100ms), a second frequency (30kHz) emitted in the second millisecond time period T2 (100-200ms), ... and a fourth frequency (10kHz) emitted in the fourth millisecond time period T4 (300-400ms), with the total duration of all millisecond time periods (400ms) within one second; the detection thickness range corresponding to the first frequency is 0-h1 mm (e.g., h1=0.5mm), the detection thickness range corresponding to the second frequency is 0-h2 mm (e.g., h2=1mm), and the detection thickness range corresponding to the fourth frequency is 0-h K mm (e.g., h4=2mm), the position of 0 mm represents the detection reference surface, and the position of h1 mm represents the depth h below the detection reference surface. K The position of mm, h1 < h2 < h K .

[0033] Among them, the frequency of the multi-frequency eddy current excitation signal generator is adjustable, and the frequencies of each range belong to an arithmetic sequence (0.05kHz, 20.05kHz, 50.05kHz, ... 200kHz).

[0034] The operation method of the metal substrate damage detection device in this embodiment includes the following steps:

[0035] Step 1: Place the non-metallic substrate 22 with the excitation coil 20 on the surface of the test area of ​​the metal substrate;

[0036] Step 2: Determine the number of magnetic field detection sensors 21 to be placed based on the area of ​​the part to be measured, and place the magnetic field detection sensors 21 in the holes of the non-metallic substrate 22 directly above the part to be measured (place the magnetic field detection sensors 21 stably on the surface of the step 23) to ensure that the effective detection surface of all magnetic field detection sensors 21 can completely cover the part to be measured.

[0037] Step 3: Based on the material and thickness of the metal substrate being tested, set the excitation signal frequency of the multi-frequency eddy current excitation signal generator;

[0038] Step 4: Turn on the multi-frequency eddy current excitation signal generator, keep the non-metallic substrate 22 and magnetic field detection sensor 21 stationary for the set time, and then perform damage detection on the next part to be tested after the set time is over. Figure 8 The gray area schematically illustrates the transverse morphology of a certain damaged area as detected.

[0039] Because multiple magnetic field detection sensors 21 are arranged in an array, and each magnetic field detection sensor 21 can be placed directly on the surface of the step 23, it is possible to flexibly and quickly install an appropriate number of magnetic field detection sensors 21 according to the area of ​​the part being measured during use, which is especially suitable for detecting irregularly shaped parts.

[0040] Compared to existing technologies, this solution combines a two-dimensional array magnetic field sensing unit with a variable excitation frequency. This allows the magnetic field sensor to be placed directly on the sample surface, enabling long-term (5 or 10 minutes) acquisition of magnetic field data images of the test piece at different excitation frequencies. It eliminates the need for lengthy scanning operations and multiple frequency changes required by linear magnetic field sensors, facilitating the acquisition of large-area (4096 mm²) data at different low excitation frequencies in a single operation. 2 -1048576mm 2 The damage data images of the tested area not only greatly reduce the difficulty of operation and simplify the operation steps, but also allow ordinary technicians to master the operation process in a short time. In particular, the operation of picking up and putting away the magnetic field detection sensor as needed is very simple and convenient. At the same time, it can improve the detection efficiency and detection range. More importantly, there is no problem of detection data distortion, which improves the accuracy of the detection results.

Claims

1. A coating-substrate-under metal damage detection device based on a two-dimensional array of magnetic field sensors, comprising an excitation coil (20) and a magnetic field detection sensor (21), characterized in that: A plurality of magnetic field detection sensors (21) are arranged in an array at the measured site, and an excitation coil (20) is arranged outside the magnetic field detection sensors (21), and the magnetic field detection sensors (21) together form a two-dimensional array magnetic field sensing unit; The two-dimensional array magnetic field sensing unit is composed of an excitation coil (20) and a plurality of magnetic field detection sensors (21) arranged in an array inside the excitation coil (20), and the spacing between adjacent magnetic field detection sensors (21) is not greater than 1mm; Each excitation coil (20) is embedded at the hole edge of a non-metal substrate (22), the connecting lines of all excitation coils (20) are buried on the non-metal substrate (22), a step (23) is arranged at the hole edge of each non-metal substrate (22) and inside the excitation coil (20), and the step (23) is used for placing the magnetic field detection sensor (21); and a wiring terminal (24) matched with the magnetic field detection sensor (21) is arranged on the surface of the step (23); It also includes a multi-frequency eddy current excitation signal generator, a magnetic field data collector, a data processing module and a display; wherein the multi-frequency eddy current excitation signal generator is used to generate a multi-frequency excitation signal and form a magnetic field at the measured site, and synchronously generate a frequency marker signal and transmit the marker signal to the magnetic field data collector; the two-dimensional array magnetic field sensing unit is used to detect the magnetic field data under different excitation frequencies, and record and extract the magnetic field data under different excitation frequencies, and transmit the magnetic field data to the magnetic field data collector; the magnetic field data collector is used to acquire the magnetic field data and the frequency marker signal, match and store the magnetic field data and the frequency marker signal, and feed back to the data processing module; the data processing module is used to generate a magnetic field data graph from the read magnetic field data and output the graph. The multi-frequency excitation signal has a frequency of 0.05 Hz-200 kHz, and the multi-frequency excitation signal comprises a first frequency emitted in a first millisecond period T1, a second frequency emitted in a second millisecond period T2, and a Kth frequency emitted in a Kth millisecond period T K K; the total time length of all the millisecond periods is controlled within one second; the detection thickness interval corresponding to the first frequency is 0-h1 mm, the detection thickness interval corresponding to the second frequency is 0-h2 mm, and the detection thickness interval corresponding to the Kth frequency is 0-h K K mm; the position at 0 mm represents a detection reference surface, the position at h1 mm represents a position with a depth of h1 mm below the detection reference surface, and the position at h2 mm represents a position with a depth of h2 mm below the detection reference surface. K K ​​ 2. The metal matrix damage detection apparatus of claim 1, wherein: The two-dimensional array magnetic field sensing unit is composed of a plurality of excitation coils (20) and a plurality of magnetic field detection sensors (21), and one magnetic field detection sensor (21) is arranged in each excitation coil (20), and the spacing between adjacent excitation coils (20) is not greater than 1mm.

3. The metal matrix damage detection apparatus of claim 2, wherein: The wiring terminal (24) is in a sheet structure, and the surface of the wiring terminal (24) is flush with the surface of the step (23).

4. The metal matrix damage detection apparatus of claim 3, wherein: The connecting lines of all excitation coils (20) are buried on the non-metal substrate (22) to form an integrated circuit board structure.

5. A method of operating the metal matrix damage detection apparatus of claim 4, wherein the steps of It includes: Step 1: Place the non-metal substrate (22) with the excitation coil (20) on the surface of the measured site of the metal base; Step 2: Determine the number of magnetic field detection sensors (21) needed according to the area of the measured site, and place the magnetic field detection sensors (21) in the holes of the non-metal substrate (22) directly above the measured site, to ensure that the effective detection surface of all magnetic field detection sensors (21) can completely cover the measured site; Step 3: Set the excitation signal frequency of the multi-frequency eddy current excitation signal generator according to the material and thickness of the measured metal base; Step 4: Turn on the multi-frequency eddy current excitation signal generator, keep the non-metal substrate (22) and the magnetic field detection sensor (21) still for a set time, and then perform damage detection on the next measured site after the set time is over.

6. The method of operation of claim 5, wherein: The magnetic field detecting sensor (21) is placed in the hole of the nonmetal substrate (22) and is smoothly placed on the surface of the step (23).

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