Electromagnetic ultrasonic thickness measurement layering and crack integrated detection system

Abstract

The invention discloses an electromagnetic ultrasonic thickness measurement layering and crack integrated detection system, which belongs to the technical field of metal flaw detection and comprises an electromagnetic ultrasonic excitation module, a magnetic field module, a first coil, a second coil and a processing module, the electromagnetic ultrasonic excitation module is used for generating pulse current. The magnetic field module can form a static bias magnetic field. The first coil is electrically connected with the electromagnetic ultrasonic excitation module and is used for exciting the sound wave signal and receiving the echo signal. The second coil and the first coil are located in the same plane and are used for collecting pulse eddy current signals. And the processing module judges the thickness, the layering defect and the crack defect of the metal plate or the metal pipe according to the echo signal and the pulsed eddy current signal. The electromagnetic ultrasonic thickness measurement layering and crack integrated detection system provided by the invention can adapt to plates or pipes made of different metal materials, not only can measure the thickness of the materials, but also can effectively detect layering and submillimeter cracks in the metal plates or pipes.

Description

Technical Field

[0001] This invention belongs to the field of metal flaw detection technology, specifically relating to an integrated electromagnetic ultrasonic thickness measurement and crack detection system. Background Technology

[0002] In modern industrial systems, metal sheets and pipes serve as key basic components, widely used in aerospace, petrochemicals, energy transmission, and high-end equipment manufacturing. Statistics show that global direct economic losses from industrial accidents caused by defects in metal components exceed tens of billions of US dollars annually, with bottom surface cracks and internal delamination defects accounting for over 37% of these accidents, highlighting the urgent need for efficient detection technologies.

[0003] Traditional nondestructive testing (NDT) techniques face multiple challenges in addressing such defects. Eddy current testing is limited by the skin effect; for non-ferromagnetic materials such as aluminum-magnesium alloys, its effective detection depth is typically less than 1 mm, failing to meet the requirements for detecting deep defects in plates thicker than 5 mm. While magnetic flux leakage testing is sensitive to surface defects in ferromagnetic materials, it requires magnetization of the tested component, and the demagnetization process increases the cost and time of inspecting precision components. Radiographic testing (such as X-rays) can penetrate thick-walled components, but its radiation protection requirements are stringent, its detection efficiency is low, and its resolution for microcracks smaller than 0.2 mm is insufficient, making it difficult to meet the requirements for detecting sub-millimeter-level defects. Traditional piezoelectric ultrasonic testing relies on coupling agents (such as machine oil or glycerin) to transmit sound energy, making it unsuitable for high-temperature (>200℃), high-pressure, or vacuum environments, and requiring manual scanning, which is unsuitable for the rapid inspection needs of automated production lines.

[0004] Electromagnetic ultrasonic testing (EMAT) technology, with its advantages of being non-contact and requiring no coupling agent, demonstrates unique value in harsh environments such as high temperatures and corrosion. It excites ultrasonic waves through the principle of electromagnetic induction, capable of generating various modes such as transverse waves, longitudinal waves, and surface waves in metal components, adapting to different testing scenarios. However, existing EMAT testing solutions face technical bottlenecks in detecting minute defects: when using an oblique incidence method to detect bottom surface cracks, the incident angle of the sound wave needs to be precisely controlled near the first critical angle, at which point the bottom surface echo signal is weak, and the defect echo is easily drowned out by noise; while using acoustic lensing to enhance the signal, the focused sound beam induces waveform mode conversion, resulting in a mixed signal of longitudinal waves, transverse waves, and surface waves in the echo, making it difficult to distinguish between thickness measurement signals and defect signals. More importantly, existing technologies struggle to achieve integrated "thickness measurement-defect detection" functionality. In industrial settings, it is typically necessary to first measure the component wall thickness with a thickness gauge and then use an ultrasonic probe for defect scanning, a cumbersome two-step process prone to positioning errors. In addition, for delamination defects on the inner wall of pipes, existing EMAT probes are limited by size and cannot easily enter the interior of small-diameter pipes for detection. When external scanning is used, the echo signal of the delamination interface is easily affected by the curvature of the pipe, resulting in a decrease in detection sensitivity. Summary of the Invention

[0005] In response to one or more of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an integrated electromagnetic ultrasonic thickness measurement and delamination and crack detection system, which can be adapted to plates or pipes of different metal materials. It can not only measure the thickness of materials, but also effectively detect delamination and sub-millimeter cracks in metal plates or pipes, thereby reducing quality defects in plates or pipes.

[0006] To achieve the above objectives, this invention provides an integrated electromagnetic ultrasonic thickness measurement system for delamination and crack detection, used to detect the thickness, delamination defects, and crack defects of metal plates or pipes, comprising: An electromagnetic ultrasonic excitation module, wherein the electromagnetic ultrasonic excitation module is used to generate pulse current; A magnetic field module, which is used to form a static bias magnetic field corresponding to the detection area of ​​the metal plate or the metal pipe; A first coil, which is electrically connected to the electromagnetic ultrasonic excitation module; The first coil is configured such that: after receiving the pulsed current, the first coil generates a first alternating magnetic field acting on the surface of the metal plate or the metal pipe, and an induced current is generated on the surface of the metal plate or the metal pipe in the first alternating magnetic field; the area of ​​the metal plate or the metal pipe where the induced current exists vibrates in a static bias magnetic field to form ultrasonic waves propagating into the interior of the metal plate or the metal pipe, and the ultrasonic waves form ultrasonic echoes after contacting the bottom surface, the delamination defect, or the crack defect; the ultrasonic echoes cause the metal plate or the metal pipe to vibrate and cut the static bias magnetic field, thereby forming a second alternating magnetic field inside the metal plate or the metal pipe, and the first coil generates an echo signal after inducing the second alternating magnetic field; A plurality of second coils are located in the same plane as the first coil, and each second coil is configured as follows: The acquisition area of ​​each second coil partially overlaps with the acquisition area of ​​the first coil, and there is no crosstalk between the signal acquisition of each second coil and the signal acquisition of the first coil. Furthermore, after the first coil generates the first alternating magnetic field, the pulsed eddy current signal formed by the first alternating magnetic field changing the static bias magnetic field is collected. The processing module receives the echo signal and the pulsed eddy current signal, and the processing module is configured to: The bottom wave signal in the echo signal is corrected based on the pulsed eddy current signal. The echo signal is analyzed using acoustic wave scattering theory to obtain the signal amplitude perturbation characteristics in the echo signal. The thickness, delamination defects, and crack defects of the metal plate or the metal pipe are determined based on the bottom wave signal and the signal amplitude perturbation characteristics.

[0007] As a further preferred embodiment of the present invention, the first coil is any one of a butterfly coil, a racetrack coil, and a spiral coil.

[0008] As a further preferred embodiment of the present invention, the first coil is a butterfly-shaped coil, wherein the number of turns of the butterfly-shaped coil is not less than 10 turns and not more than 20 turns, the wire width is not less than 0.1 mm and not more than 0.6 mm, the wire spacing is not more than 0.2 mm, and the overall length and width of the butterfly-shaped coil do not exceed 40 mm.

[0009] As a further preferred embodiment of the present invention, each of the second coils is evenly arranged on the outer periphery of the first coil.

[0010] As a further preferred embodiment of the present invention, the second coil is a rectangular coil.

[0011] As a further preferred embodiment of the present invention, the non-working area of ​​the first coil is provided with a shielding layer for shielding the excited eddy currents in the side area inside the metal plate or the metal tube.

[0012] As a further preferred embodiment of the present invention, the shielding layer is a copper shielding layer with a thickness of 0.1 mm.

[0013] As a further preferred embodiment of the present invention, the center-to-center distance between the first coil and the second coil is greater than 1.5 mm and less than 3.0 mm.

[0014] As a further preferred embodiment of the present invention, it also includes a motion module and a composite imaging module; The motion module drives the first coil and the second coil to move, and is used to collect the echo signal and the pulsed eddy current signal of the entire area of ​​the metal plate or the metal pipe. The processing module generates detection information for the metal sheet or the metal pipe based on the echo signals and pulsed eddy current signals from all regions. The composite imaging module receives detection information to generate an image model of defects in the metal sheet or the metal pipe.

[0015] As a further preferred embodiment of the present invention, the electromagnetic induction intensity of the static bias magnetic field is greater than 0.1T and less than 2T.

[0016] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: (1) The electromagnetic ultrasonic thickness measurement and delamination / crack integrated detection system of the present invention includes an electromagnetic ultrasonic excitation module for generating pulsed current. A first coil is electrically connected to the electromagnetic ultrasonic excitation module and is used to receive the excited acoustic signal after the pulsed current and the echo signal generated by the excited acoustic signal acting on the metal plate or metal pipe. Each second coil is in the same plane as the first coil and is used to collect pulsed eddy current signals. The processing module receives the echo signal and the pulsed eddy current signal and is used to determine the thickness, delamination defects, and crack defects of the metal plate or metal pipe based on the echo signal and the pulsed eddy current signal. This detection system can adapt to plates or pipes of different metal materials. It can not only measure the thickness of the material, but also effectively detect delamination and sub-millimeter cracks in the metal plate or pipe, thereby reducing quality defects in the plate or pipe.

[0017] (2) The electromagnetic ultrasonic thickness measurement layer and crack integrated detection system of the present invention provides a copper shielding layer with a thickness of 0.1 mm below the non-working area of ​​the first coil, thereby shielding the eddy currents excited in the test piece in the side area, and thus preventing the generation of transverse and longitudinal waves with different polarization directions under the action of the static bias magnetic field, thereby further reducing the interference to the detection results.

[0018] (3) The electromagnetic ultrasonic thickness and delamination and crack integrated detection system of the present invention is accurate and convenient to use. It uses a butterfly-shaped first coil to excite the acoustic signal after receiving the pulse current and to receive the echo signal of the acoustic signal acting on the metal part to be tested. Combined with the second coil set around the first coil, the user can accurately obtain the echo signal and pulse eddy current signal of the metal part to be tested. Then, the processing module corrects the amplitude of the bottom wave signal in the echo signal according to the pulse eddy current signal. Then, the thickness, delamination defects and crack defects of the metal plate or metal pipe are judged according to the corrected echo signal, thereby realizing the accurate detection of the metal plate or metal pipe. It has good promotion value and application prospects. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the integrated electromagnetic ultrasonic thickness measurement and crack detection system in this embodiment of the invention; Figure 2 This is a schematic diagram of the detection echo of the integrated electromagnetic ultrasonic thickness measurement and crack detection system in an embodiment of the present invention; Figure 3 This is an EMAT thickness measurement signal diagram of the stepped aluminum plate in Embodiment 1 of the present invention; Figure 4 This is an EMAT thickness measurement signal diagram of the stepped aluminum plate in Comparative Example 1 of this invention; Figure 5 This is a B-scan experimental signal diagram of the butterfly-shaped coil EMAT in Embodiment 2 of the present invention; Figure 6 These are EMAT experimental waveforms at different crack depths in Embodiment 3 of the present invention.

[0020] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Detection system; 2. Metal sheet; 3. Bottom surface echo; 4. Defect echo; 5. Delamination defect; 6. First coil; 7. Second coil; 8. Permanent magnet. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] Example: Please see Figures 1-6 The electromagnetic ultrasonic thickness measurement and delamination and crack detection system in the preferred embodiment of the present invention can be adapted to plates or pipes of different metal materials. It can not only measure the thickness of the material, but also effectively detect delamination and sub-millimeter cracks in the metal plate or pipe, thereby reducing quality defects in the plate or pipe.

[0027] Specifically, in a preferred embodiment of this application, the detection system 1 includes an electromagnetic ultrasonic excitation module, a first coil 6, a plurality of second coils 7, a magnetic field module, and a processing module. The electromagnetic ultrasonic excitation module is used to generate pulsed current. The magnetic field module is used to form a static bias magnetic field corresponding to the detection area of ​​the metal sheet or metal pipe. The first coils 6 are electrically connected to the electromagnetic ultrasonic excitation module.

[0028] In actual use, after receiving the pulse current, the first coil 6 generates a first alternating magnetic field that acts on the surface of the metal plate 2 or the metal pipe. The surface of the metal plate 2 or the metal pipe generates an induced current in the first alternating magnetic field. The metal plate 2 or the metal pipe with the induced current vibrates in the static bias magnetic field to form ultrasonic waves that propagate into the interior of the metal plate 2 or the metal pipe. After contacting the bottom surface, the delamination defect 5, or the crack defect, the ultrasonic waves form an ultrasonic echo. The ultrasonic echo causes the metal plate 2 or the metal pipe to vibrate and cut the static bias magnetic field to form a second alternating magnetic field inside the metal plate 2 or the metal pipe. The first coil 6 generates an echo signal after inducing the second alternating magnetic field.

[0029] Furthermore, each of the second coils 7 and the first coil 6 is located in the same plane, and the acquisition area of ​​each second coil 7 partially overlaps with the acquisition area of ​​the first coil 6. Moreover, there is no crosstalk between the signal acquisition of each second coil 7 and the signal acquisition of the first coil 6. In practical use, the second coil 7 can acquire the pulsed eddy current signal formed by the first alternating magnetic field changing the static bias magnetic field after the first coil 6 generates the first alternating magnetic field.

[0030] More preferably, the processing module receives the echo signal and the pulsed eddy current signal. The processing module corrects the bottom wave signal in the echo signal according to the pulsed eddy current signal, and then uses the acoustic wave scattering theory to analyze the echo signal, obtain the signal amplitude disturbance characteristics in the echo signal, and determine the thickness of the metal plate 2 or the metal pipe, the delamination defect 5 and the crack defect according to the bottom wave signal and the signal amplitude disturbance characteristics.

[0031] In the specific signal analysis process, the processing module detects delamination and cracks by analyzing the signal amplitude perturbation characteristics in the echo signal.

[0032] For bottom or inner wall cracks, when such defects exist within the detection area of ​​the first coil 6, the acoustic energy generated by the metal plate 2 or metal pipe to be detected will attenuate, causing a change in the amplitude of the bottom echo 3. By accurately detecting the change in the amplitude of the bottom echo 3 within the defect area, the crack can be identified, located, and quantitatively analyzed. That is, a defect echo 4 will be received before the bottom echo 3. By judging the time difference between the bottom echo 3 and the defect echo 4, parameters such as the location of the defect can be determined.

[0033] When there is a delamination defect 5 in the metal sheet 2 or metal pipe, according to the sound wave scattering theory, when the ultrasonic wave encounters delamination, it will be reflected, refracted and waveform mode transformed. Then, by analyzing the defect echo 4, we can determine whether there is a delamination defect 5, the location of the delamination defect 5 and the depth of the delamination defect 5.

[0034] Furthermore, in a preferred embodiment of this application, the selection of the first coil 6 is improved based on the material and shape adaptability of the metal pipe or metal sheet 2 to be tested. Specifically, the selection and setting of the first coil 6 includes the following steps: A simulation model was constructed using finite element simulation software. Based on the simulation model, the sound field distribution, beam direction characteristics, and the influence of coil parameters on the excitation sound field intensity and directivity of the first coil 6 were determined, thereby enabling analysis and optimization of detection performance. Using an orthogonal experimental method, with the amplitude of the first-order bottom wave determined by the pulsed eddy current signal received by the second coil 7 as the evaluation standard, the key parameters of the coil were simulated, analyzed, and optimized, thus determining the selection of the first coil 6 and its parameters.

[0035] Further preferably, in the preferred embodiment of this application, the first coil 6 is any one of a butterfly-shaped coil, a racetrack-shaped coil, and a spiral coil. Preferably, the parameters of the first coil 6 include the wire width, wire spacing, wire height, and number of coil turns.

[0036] More specifically, in a preferred embodiment of this application, the first coil 6 is a butterfly-shaped coil. Specifically, the first coil 6 is a butterfly-shaped coil with 10-20 turns, a wire width of 0.1-0.6 mm, a wire spacing of no more than 0.2 mm, and an overall length and width not exceeding 40 mm. More preferably, the butterfly-shaped coil has 11 turns, a wire width of 0.1 mm, and a guide spacing of 0.2 mm.

[0037] Furthermore, in a preferred embodiment of this application, the magnetic field module includes a permanent magnet 8 or an electromagnet disposed on one side of the workpiece to be tested. More preferably, the electromagnetic induction intensity of the static bias magnetic field is between 0.1T and 2T.

[0038] In the actual testing process, the first coil 6 receives pulsed current and generates an alternating magnetic field; the surface of the material generates surface induced eddy currents under the action of the alternating magnetic field; the induced eddy currents generate Lorentz force in the static bias magnetic field, and the material vibrates and excites ultrasonic waves under the action of the Lorentz force field; the ultrasonic waves propagate in the material to be tested, causing the material to vibrate synchronously, so as to drive the material to cut the magnetic field lines of the static bias magnetic field, thereby forming induced eddy currents, and the first coil 6 detects the change in the magnetic field and then obtains the echo signal.

[0039] Furthermore, in a preferred embodiment of this application, the second coil 7 is evenly arranged around the first coil 6 so that the second coil 7 can accurately statically bias the change of the magnetic field, thereby generating an accurate pulsed eddy current signal.

[0040] More preferably, in the preferred embodiment of this application, a plurality of second coils 7 are uniformly arranged circumferentially around the first coil 6. Each second coil 7 is arranged in a ring array, a rectangular array, or symmetrically around the first coil 6, thereby ensuring that the second coils 7 can accurately collect the magnetic field changes in the area surrounding the first coil 6.

[0041] More specifically, in a preferred embodiment of this application, two second coils 7 are symmetrically arranged on both sides of the first coil 6. Preferably, the center-to-center distance between the first coil 6 and the second coil 7 is 1.5~3.0mm.

[0042] Furthermore, in a preferred embodiment of this application, a shielding layer is provided on the non-working area of ​​the first coil 6 facing the metal plate 2 or metal tube to shield the excited eddy currents in the side region inside the metal plate 2 or metal tube, thereby preventing the generation of transverse and longitudinal waves with different polarization directions under the action of a static bias magnetic field, and ensuring the accuracy of the detection results. Preferably, the shielding layer is a copper shielding layer with a thickness of 0.1 mm.

[0043] Further preferably, in a preferred embodiment of this application, the detection system 1 includes a housing with a receiving space inside the housing and an opening communicating with the outside of the housing. A first coil 6 and each of the second coils 7 are disposed within the receiving space, and the planes on which the first coil 6 and each of the second coils 7 are located are parallel to the opening. The first coil 6 and the second coils 7 are aligned with the opening, enabling the first coil 6 and the second coils 7 to generate sound signals or receive laser sound wave signals and echo signals. Preferably, a permanent magnet 8 is disposed inside the housing, and / or the permanent magnet 8 is disposed on the side of the metal plate or metal tube facing away from the housing.

[0044] Furthermore, in a preferred embodiment of this application, the processing module analyzes the signal amplitude disturbance characteristics of the echo signal and the pulse eddy current signal based on the acoustic wave scattering theory to determine the thickness of the metal plate 2 or the metal pipe, the delamination defect 5, and the crack defect.

[0045] Further preferably, in a preferred embodiment of this application, the detection system 1 further includes a motion module and a composite imaging module. The motion module drives the first coil 6 and the second coil 7 to move, for acquiring echo signals and pulsed eddy current signals from the entire area of ​​the metal plate or metal pipe. Simultaneously, the processing module generates detection information of the metal plate 2 or metal pipe based on the echo signals and pulsed eddy current signals from the entire area. Correspondingly, the composite imaging module receives the detection information to generate an image model of defects in the metal plate 2 or metal pipe.

[0046] More specifically, in the preferred embodiment of this application, the material of the metal sheet 2 or the metal tube can be any one of carbon steel, low alloy steel, stainless steel, aluminum alloy, copper alloy, and titanium alloy.

[0047] Furthermore, in a preferred embodiment of this application, the processing module is located in the host computer, and preferably, the composite imaging module is also located in the host computer.

[0048] Example 1 A stepped aluminum plate with a thickness gradually increasing from 6 to 10 mm was selected as the test specimen. A normal magnetized transverse wave (SonemaT, HWS2035VC) probe was used as comparative example 1. The coil in comparative example 1 is a spiral coil with 20 turns, a wire width of 0.2 mm, and a guide spacing of 0.4 mm.

[0049] Furthermore, the first coil 6 in the detection system 1 is a butterfly-shaped coil with 11 turns, a wire width of 0.1 mm, and a wire spacing of 0.2 mm. Simultaneously, the electromagnetic ultrasonic excitation module uses a PR5000 Pulser-Receiver developed by Sonemat in the UK as the excitation and receiving device, with the excitation frequency set to 5 MHz and the repetition frequency to 1 kHz. An oscilloscope is used for signal reception and acquisition.

[0050] Furthermore, two probes were used to scan from a 6mm thick area to a 10mm thick area of ​​the stepped aluminum plate, and the echo signals of the two probes at different thicknesses were extracted and transmitted to the host computer for analysis.

[0051] like Figure 3 and Figure 4 As shown in the diagram, the analysis results from the host computer indicate that both probes can acquire multiple echo signals with good signal-to-noise ratios. When the aluminum plate thickness varies within a small range, the echo amplitude fluctuations are relatively small and have virtually no impact on crack detection using the bottom echo amplitude characteristics. Furthermore, extracting the time interval between adjacent echo signal peaks allows for the measurement of the aluminum plate thickness.

[0052] Example 2 A 10mm thick aluminum plate was selected as the test specimen, and the bottom surface of the aluminum plate was machined with cracks with a width of 0.2~1.0mm and a depth of 0.5mm. Meanwhile, the detection system 1 used in Example 2 is the same as the detection system 1 in Example 1.

[0053] Comparative Example 2: The first coil 6 in the detection system 1 of Comparative Example 2 is a spiral coil, and the other structures are the same as those in the detection system 1 of Example 2.

[0054] In the actual overload test, the housing containing the first coil 6 and the second coil 7 is placed on the surface of the aluminum plate, with its center roughly aligned with the crack location. The electromagnetic ultrasonic excitation module is activated, and the PR5000 excites the butterfly-shaped coil to emit high-frequency pulses, exciting ultrasonic waves to propagate in the aluminum plate. The oscilloscope acquires the echo signal received by the butterfly-shaped coil and transmits it to the host computer for analysis.

[0055] Correspondingly, Comparative Example 2 also used the same steps to test the aluminum plate.

[0056] like Figure 5As shown (the orange curve at the top is the echo signal collected in Comparative Example 2, and the blue curve at the bottom is the echo signal collected in Example 2), based on the analysis of the collected signal waveforms, the detection system 1 exhibits obvious amplitude disturbance signals. By analyzing the amplitude disturbance signals, sub-millimeter level cracks can be accurately detected.

[0057] Furthermore, when the helical coil electromagnetic ultrasonic probe in Comparative Example 2 was used for testing, although an amplitude disturbance trend could be observed when scanning the crack area, the effective signal was submerged in noise, making it difficult to accurately determine the existence and size of the crack. Compared with the detection results of the butterfly coil detection system 1 in Example 2, the bottom wave amplitude disturbance was not obvious and the crack characteristics could not be clearly presented. It is not difficult to conclude that when detecting submillimeter-level cracks, the detection performance of the traditional helical coil electromagnetic ultrasonic detection system 1 is significantly inferior to that of the butterfly coil electromagnetic ultrasonic detection system 1.

[0058] Example 3 A 10mm thick aluminum plate was selected as the test specimen. The bottom surface of the aluminum plate was machined with cracks 0.3mm wide and 0.1-0.5mm deep. The detection system 1 in Example 3 is the same as the detection system 1 in Example 1. Its detection steps are the same as those of the detection system 1 in Example 2.

[0059] like Figure 6 As shown in the figure, the amplitude of the primary bottom wave decreases with the increase of the defect depth, and bottom surface cracks with a width of 0.3 mm and a depth of 0.1~0.5 mm can be accurately detected.

[0060] Example 4 A 10mm thick aluminum plate was selected as the test piece. The aluminum plate has a delamination defect 5 inside (the depth and location of the delamination defect 5 in the model are known), and the detection system 1 in Example 4 is the same as the detection system 1 in Example 1.

[0061] In the actual testing process, the housing including the butterfly-shaped coil and the second coil 7 is placed at the corresponding position on the surface of the aluminum plate. The PR5000 excites the butterfly-shaped coil to emit high-frequency pulses, exciting ultrasonic waves to propagate in the aluminum plate. When the ultrasonic waves encounter internal delamination, reflection, refraction, and waveform mode conversion occur, and the resulting defect echo 4 is received by the butterfly-shaped coil. The oscilloscope collects the echo signal and transmits it to the host computer for analysis.

[0062] By analyzing the characteristics of defect echo 4 (such as amplitude, phase, propagation time, etc.), the presence, location, and depth of layered defect 5 can be determined.

[0063] The electromagnetic ultrasonic thickness and delamination / crack integrated detection system of this invention is accurate and easy to use. It uses a butterfly-shaped first coil 6 to excite an acoustic signal after receiving a pulse current and to receive the echo signal of the acoustic signal acting on the metal part under test. Combined with a second coil 7 set around the first coil 6, the user can accurately obtain the echo signal and pulsed eddy current signal of the metal part under test. Then, the processing module corrects the amplitude of the bottom wave signal in the echo signal according to the pulsed eddy current signal. After that, the thickness, delamination defect 5 and crack defect of the metal plate 2 or metal pipe are determined according to the corrected echo signal, thereby realizing accurate detection of the metal plate 2 or metal pipe. It has good promotion value and application prospects.

[0064] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the principles and guidelines of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated electromagnetic ultrasonic thickness measurement and delamination / crack detection system, used to detect the thickness, delamination defects, and crack defects of metal plates or metal pipes, characterized in that, include: An electromagnetic ultrasonic excitation module, wherein the electromagnetic ultrasonic excitation module is used to generate pulse current; A magnetic field module, which is used to form a static bias magnetic field corresponding to the detection area of ​​the metal plate or the metal pipe; A first coil, which is electrically connected to the electromagnetic ultrasonic excitation module; The first coil is configured such that: after receiving the pulsed current, the first coil generates a first alternating magnetic field acting on the surface of the metal plate or the metal pipe, and an induced current is generated on the surface of the metal plate or the metal pipe in the first alternating magnetic field; the area of ​​the metal plate or the metal pipe where the induced current exists vibrates in a static bias magnetic field to form ultrasonic waves propagating into the interior of the metal plate or the metal pipe, and the ultrasonic waves form ultrasonic echoes after contacting the bottom surface, the delamination defect, or the crack defect; the ultrasonic echoes cause the metal plate or the metal pipe to vibrate and cut the static bias magnetic field, thereby forming a second alternating magnetic field inside the metal plate or the metal pipe, and the first coil generates an echo signal after inducing the second alternating magnetic field; A plurality of second coils are located in the same plane as the first coil, and each second coil is configured as follows: The acquisition area of ​​each second coil partially overlaps with the acquisition area of ​​the first coil, and there is no crosstalk between the signal acquisition of each second coil and the signal acquisition of the first coil. Furthermore, after the first coil generates the first alternating magnetic field, the pulsed eddy current signal formed by the first alternating magnetic field changing the static bias magnetic field is collected. A processing module, which receives the echo signal and the pulsed eddy current signal, is configured to: The bottom wave signal in the echo signal is corrected based on the pulsed eddy current signal. The echo signal is analyzed using acoustic wave scattering theory to obtain the signal amplitude perturbation characteristics in the echo signal. The thickness, delamination defects, and crack defects of the metal plate or the metal pipe are determined based on the bottom wave signal and the signal amplitude perturbation characteristics.

2. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 1, wherein, The first coil is any one of a butterfly coil, a racetrack coil, and a spiral coil.

3. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 2, wherein, The first coil is a butterfly-shaped coil, with the number of turns being no less than 10 and no more than 20, the wire width being no less than 0.1 mm and no more than 0.6 mm, the wire spacing being no more than 0.2 mm, and the overall length and width of the butterfly-shaped coil not exceeding 40 mm.

4. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to any one of claims 1 to 3, wherein, Each of the second coils is evenly arranged on the outer periphery of the first coil.

5. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 4, wherein, The second coil is a rectangular coil.

6. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to any one of claims 1 to 3 and 5, wherein, The non-working area of ​​the first coil facing the metal plate or metal tube is provided with a shielding layer to shield the excited eddy current in the side area inside the metal plate or metal tube.

7. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 6, wherein, The shielding layer is a copper shielding layer with a thickness of 0.1 mm.

8. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to any one of claims 1 to 3, 5, and 7, wherein, The center-to-center distance between the first coil and the second coil is greater than 1.5 mm and less than 3.0 mm.

9. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 1, wherein, It also includes a motion module and a composite imaging module; The motion module drives the first coil and the second coil to move, and is used to collect the echo signal and the pulsed eddy current signal of the entire area of ​​the metal plate or the metal pipe. The processing module generates detection information for the metal sheet or the metal pipe based on the echo signals and pulsed eddy current signals from all regions. The composite imaging module receives detection information to generate an image model of defects in the metal sheet or the metal pipe.

10. The integrated electromagnetic ultrasonic thickness measurement and crack detection system according to claim 1, wherein, The electromagnetic induction intensity of the static bias magnetic field is greater than 0.1T and less than 2T.

Images