Electromagnetic ultrasonic and magnetic flux leakage composite detection device and method

Abstract

The present invention discloses an electromagnetic ultrasound and magnetic flux leakage composite detection device and method, including a permanent magnet, an orthogonal butterfly coil, a three-axis Hall sensor, a magnetic flux leakage signal conditioning and data acquisition circuit, a signal generator, a power amplifier, a duplexer and a signal amplifier. The present invention makes full use of the advantages of electromagnetic ultrasound and magnetic flux leakage detection technology to achieve simultaneous detection of surface defects and internal defects of metal specimens, and also achieves the measurement of the thickness of metal specimens. In addition, a single permanent magnet structure is adopted to simplify the structural size and complexity. Through the design of the orthogonal butterfly coil, the signal-to-noise ratio is improved, and the detection of cracks is achieved.

Description

Technical Field

[0001] The present invention relates to the field of nondestructive testing, and in particular to an electromagnetic ultrasound and magnetic flux leakage composite testing device and method. Background Art

[0002] Metal materials are widely used in oil and gas pipelines, storage tanks and other equipment. However, as the service life increases, metal materials may cause defects such as cracks and through holes in these equipment due to corrosion, third-party damage and other factors, and may even cause serious accidents. Therefore, it is of great significance to conduct regular inspection and maintenance of these metal equipment. Non-destructive testing technologies mainly include: magnetic flux leakage testing, electromagnetic ultrasonic testing, eddy current testing, ultrasonic testing, etc. The location of defects is usually random. A single non-destructive test cannot meet the requirements of defect detection at different locations due to its detection limitations, so it is necessary to use a combination of different technologies to detect defects at different locations.

[0003] At present, although the electromagnetic ultrasonic and magnetic flux leakage composite detection equipment disclosed in patents CN116642532A and CN102661995A can simultaneously detect defects on the surface and bottom of the test piece, the disadvantage is that both use a double permanent magnet with a yoke iron structure to provide the required magnetic field, which is complex in structure and large in size. In addition, both use spiral coils, which have the disadvantages of a middle detection blind area and a low signal-to-noise ratio, and cannot achieve crack detection. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an electromagnetic ultrasound and magnetic flux leakage composite detection device and method, which solves the problems of the existing electromagnetic ultrasound and magnetic flux leakage composite detection equipment having a complex structure, large size, an intermediate detection blind area and a low signal-to-noise ratio.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] Provided is an electromagnetic ultrasonic and magnetic flux leakage composite detection device, which includes a permanent magnet, an orthogonal butterfly coil, a three-axis Hall sensor, a magnetic flux leakage signal conditioning and data acquisition circuit, a signal generator, a power amplifier, a duplexer and a signal amplifier;

[0007] The three-axis Hall sensor is arranged in front of the orthogonal butterfly coil, and the orthogonal butterfly coil is arranged below the permanent magnet;

[0008] A signal generator, used for generating a pulse signal;

[0009] A power amplifier, used to amplify the pulse signal;

[0010] A duplexer for transmitting the amplified pulse signal to the orthogonal butterfly coil;

[0011] A quadrature butterfly coil is used to excite a pair of orthogonal shear waves and generate a voltage signal based on the reflected echo;

[0012] A signal amplifier, used to amplify and output the voltage signal generated by the orthogonal butterfly coil;

[0013] Three-axis Hall sensor for detecting surrounding magnetic flux;

[0014] The leakage magnetic signal conditioning and data acquisition circuit is used to condition and output the magnetic flux detected by the three-axis Hall sensor;

[0015] The amplified voltage signal output by the signal amplifier is used to detect cracks and internal defects of the tested piece; the output data of the leakage magnetic signal conditioning and data acquisition circuit is used to detect surface defects of the tested piece.

[0016] Furthermore, the orthogonal butterfly coil is composed of two identical butterfly coils that are orthogonal to each other and are manufactured through a flexible printed circuit board. The two coils are perpendicular to each other in the current direction and the shear force direction.

[0017] Furthermore, copper foil is arranged between the orthogonal butterfly coil and the permanent magnet.

[0018] Furthermore, the permanent magnet is a cylindrical permanent magnet with a diameter of 25 mm and a height of 40 mm.

[0019] Furthermore, there are four three-axis Hall sensors arranged in a row, and the distance between two adjacent three-axis Hall sensors is 4 mm; and the orthogonal butterfly coils are on the axes of the four three-axis Hall sensors.

[0020] Furthermore, it also includes a vehicle body, a three-axis Hall sensor and an orthogonal butterfly coil are all located at the bottom of the vehicle body, and wheels are arranged at the four corners of the bottom of the vehicle body.

[0021] A detection method based on an electromagnetic ultrasound and magnetic flux leakage composite detection device is provided, which comprises the following steps:

[0022] S1. Place the orthogonal butterfly coil in the electromagnetic ultrasound and magnetic flux leakage composite detection device above the test piece;

[0023] S2, a pair of orthogonal shear waves are excited by the orthogonal butterfly coil, so that eddy currents are induced on the surface of the tested object, and ultrasonic waves are generated under the action of the magnetic field generated by the permanent magnet;

[0024] S3, obtaining the voltage signal generated by the orthogonal butterfly coil, and respectively amplifying and outputting the voltage signals generated by the two coils in the orthogonal butterfly coil through a signal amplifier;

[0025] S4, conditioning and outputting the magnetic flux detected by the three-axis Hall sensor through the magnetic leakage signal conditioning and data acquisition circuit;

[0026] S5. Detect cracks and internal defects of the tested piece through the amplified voltage signal output by the signal amplifier; detect surface defects of the tested piece through the output data of the leakage magnetic signal conditioning and data acquisition circuit.

[0027] Furthermore, the specific method of testing the tested piece in step S5 includes the following sub-steps:

[0028] S5-1, determining whether the amplitudes of the signals after the voltages generated by the two coils are respectively amplified are the same, if so, determining that the tested piece has no cracks; otherwise, determining that the tested piece has cracks; and proceeding to step S5-2;

[0029] S5-2, calculate the thickness of the test piece by the time difference between the excitation signal of the orthogonal butterfly coil and the reflected echo signal; determine whether there is a defect echo signal between the excitation signal of the orthogonal butterfly coil and the reflected echo signal, if so, determine that the test piece has an internal defect; otherwise, determine that the test piece has no internal defect; enter step S5-3;

[0030] S5-3. Based on the output data of the leakage magnetic signal conditioning and data acquisition circuit, determine whether the three-axis Hall sensor detects a magnetic flux greater than the set threshold. If so, it is determined that the test piece has surface defects; otherwise, it is determined that the test piece does not have surface defects.

[0031] Furthermore, after step S5, the following steps are also included:

[0032] S6. Process the output data of the leakage magnetic signal conditioning and data acquisition circuit by a computer to obtain the defect size of the tested piece; and display the output of the signal amplifier by an oscilloscope.

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention makes full use of the advantages of electromagnetic ultrasound and magnetic flux leakage detection technology to achieve simultaneous detection of surface defects and internal defects of metal specimens, and also achieves the measurement of the thickness of metal specimens. In addition, a single permanent magnet structure is adopted to simplify the structural size and complexity. Through the design of orthogonal butterfly coils, the signal-to-noise ratio is improved, and crack detection is achieved.

[0035] 2. The electromagnetic ultrasound and magnetic flux leakage sensors of the present invention use different receiving circuits so that the two signals do not interfere with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the simulation structure of the electromagnetic ultrasonic and magnetic flux leakage composite detection device;

[0037] Figure 2 Schematic diagram of the change of magnetic field when there is a through hole on the surface;

[0038] Figure 3 This is a schematic diagram of the arrangement of four three-axis Hall sensors;

[0039] Figure 4 Schematic diagram of orthogonal butterfly coil;

[0040] Figure 5 This is the block diagram of the electromagnetic ultrasonic and magnetic flux leakage composite defect detection experimental system;

[0041] Figure 6 It is the electromagnetic ultrasonic signal when there is an internal defect;

[0042] Figure 7 It is the electromagnetic ultrasonic signal when there is no crack;

[0043] Figure 8 It is the electromagnetic ultrasonic signal when there is a crack;

[0044] Fig. 9 This is a comparison diagram between the electromagnetic ultrasonic signal detected by the device and the signal of the traditional electromagnetic ultrasonic sensor;

[0045] Fig.10 It is the magnetic leakage signal when there are surface defects.

[0046] Among them: 1. Leakage magnetic data interface; 2. Electromagnetic ultrasonic interface; 3. Leakage magnetic signal conditioning and data acquisition circuit; 4. Three-axis Hall sensor; 5. Orthogonal butterfly coil; 6. Permanent magnet. DETAILED DESCRIPTION

[0047] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0048] like Figure 1 and Figure 5 As shown, the electromagnetic ultrasound and leakage magnetic flux composite detection device includes a permanent magnet 6, an orthogonal butterfly coil 5, a three-axis Hall sensor 4, a leakage magnetic flux signal conditioning and data acquisition circuit 3, a signal generator, a power amplifier, a duplexer and a signal amplifier;

[0049] The three-axis Hall sensor 4 is arranged in front of the orthogonal butterfly coil 5, and the orthogonal butterfly coil 5 is arranged below the permanent magnet 6;

[0050] A signal generator, used for generating a pulse signal;

[0051] A power amplifier, used to amplify the pulse signal;

[0052] A duplexer for transmitting the amplified pulse signal to the orthogonal butterfly coil;

[0053] The orthogonal butterfly coil 5 is used to excite a pair of orthogonal shear waves and generate a voltage signal according to the reflected echo;

[0054] A signal amplifier, used to amplify and output the voltage signal generated by the orthogonal butterfly coil;

[0055] A three-axis Hall sensor 4, used to detect surrounding magnetic flux;

[0056] The leakage magnetic signal conditioning and data acquisition circuit 3 is used to condition and output the magnetic flux detected by the three-axis Hall sensor;

[0057] The amplified voltage signal output by the signal amplifier is used to detect cracks and internal defects of the tested piece; the output data of the leakage magnetic signal conditioning and data acquisition circuit 3 is used to detect surface defects of the tested piece. In this embodiment, the defects include corrosion, metal loss, weld defects and through-holes.

[0058] In the specific implementation process, the electromagnetic ultrasound and magnetic flux leakage composite detection device also includes a magnetic flux leakage data interface 1 connected to the magnetic flux leakage signal conditioning and data acquisition circuit 3, and an electromagnetic ultrasound interface 2 connected to the signal amplifier, which is convenient for external data transmission. The magnetic flux leakage data interface 1 can use a USB Type-C interface. The electromagnetic ultrasound interface 2 is an aviation socket and plug.

[0059] In this embodiment, in order to prevent ultrasound from being generated in the permanent magnet 6 and further improve the signal-to-noise ratio, a copper foil is provided between the orthogonal butterfly coil 5 and the permanent magnet 6. The permanent magnet 6 is a cylindrical permanent magnet with a diameter of 25 mm and a height of 40 mm.

[0060] In this embodiment, the signal generator, power amplifier, duplexer, orthogonal butterfly coil 5, copper foil, permanent magnet 6, and electromagnetic ultrasonic interface 2 constitute an electromagnetic ultrasonic sensing component. The three-axis Hall sensor 4, leakage magnetic signal conditioning and data acquisition circuit 3, permanent magnet 6, and leakage magnetic data interface 1 constitute a leakage magnetic sensing component.

[0061] Figure 2 This is a schematic diagram of the change in magnetic field when there are surface defects in the tested object. It can be seen that when there are surface defects in the tested object, leakage magnetic field will be generated.

[0062] like Figure 3As shown, there are four three-axis Hall sensors 4 arranged in a row, and the distance between two adjacent three-axis Hall sensors 4 is 4 mm; the orthogonal butterfly coils 5 are on the axes of the four three-axis Hall sensors 4 .

[0063] like Figure 4 As shown, the orthogonal butterfly coil 5 is composed of two identical butterfly coils that are orthogonal to each other and are made through a flexible printed circuit board. The two coils are perpendicular to each other in the current direction and the shear force direction.

[0064] The electromagnetic ultrasonic and magnetic flux leakage composite detection device also includes a vehicle body. The three-axis Hall sensor 4 and the orthogonal butterfly coil 5 are both located at the bottom of the vehicle body. Wheels are arranged at the four corners of the bottom of the vehicle body.

[0065] In this embodiment, the electromagnetic ultrasound and magnetic flux leakage composite detection method includes the following steps:

[0066] S1, placing the orthogonal butterfly coil 5 in the electromagnetic ultrasound and magnetic flux leakage composite detection device above the test piece;

[0067] S2, a pair of orthogonal transverse waves are excited by the orthogonal butterfly coil 5, so that eddy currents are induced on the surface of the tested piece, and ultrasonic waves are generated under the action of the magnetic field generated by the permanent magnet 6;

[0068] S3, obtaining the voltage signal generated by the orthogonal butterfly coil 5, and respectively amplifying and outputting the voltage signals generated by the two coils in the orthogonal butterfly coil 5 through a signal amplifier;

[0069] S4, conditioning and outputting the magnetic flux detected by the three-axis Hall sensor 4 through the magnetic leakage signal conditioning and data acquisition circuit 3;

[0070] S5, detecting cracks and internal defects of the tested piece through the amplified voltage signal output by the signal amplifier; detecting surface defects of the tested piece through the output data of the leakage magnetic signal conditioning and the data acquisition circuit 3;

[0071] S6. Process the output data of the leakage magnetic signal conditioning and data acquisition circuit 3 by a computer to obtain the defect size of the tested piece; and display the output of the signal amplifier by an oscilloscope.

[0072] The specific method of testing the tested piece in step S5 includes the following sub-steps:

[0073] S5-1, determining whether the amplitudes of the signals after the voltages generated by the two coils are respectively amplified are the same, if so, determining that the tested piece has no cracks; otherwise, determining that the tested piece has cracks; and proceeding to step S5-2;

[0074] S5-2, calculate the thickness of the test piece by the time difference between the excitation signal of the orthogonal butterfly coil and the reflected echo signal; determine whether there is a defect echo signal between the excitation signal of the orthogonal butterfly coil and the reflected echo signal, if so, determine that the test piece has an internal defect; otherwise, determine that the test piece has no internal defect; enter step S5-3;

[0075] S5-3. Based on the output data of the leakage magnetic signal conditioning and data acquisition circuit, determine whether the three-axis Hall sensor detects a magnetic flux greater than the set threshold. If so, it is determined that the test piece has surface defects; otherwise, it is determined that the test piece does not have surface defects.

[0076] The thickness calculation expression of the tested piece is: Wherein, c represents the propagation speed of ultrasonic waves in the test piece, and t is the time difference between two adjacent echoes.

[0077] In the specific implementation process, the distance between the orthogonal butterfly coil 5 and the test piece can be 1mm. The electromagnetic ultrasonic sensor component induces eddy currents on the surface of the test piece, and generates ultrasonic waves under the magnetic field generated by the permanent magnet 6. When propagated to the surface and bottom of the test piece, reflected echoes will be generated, and voltage signals will be generated in the orthogonal butterfly coil 5. After being amplified by the signal amplifier, they will be transmitted to the oscilloscope for display. Figure 6 Shown are the defect and bottom echo signals.

[0078] The orthogonal butterfly coil 5 includes a coil A and a coil B. When there is no crack, the ultrasonic amplitudes generated by coil A and coil B are equal. When there is a crack parallel to coil B, since the polarization direction of the transverse wave generated by coil B is perpendicular to the crack direction, the presence of the crack causes the sound wave to be significantly scattered at the crack, and the echo energy is reduced. On the contrary, the polarization direction of the transverse wave generated by coil A is parallel to the crack direction, and since the size of the crack is small, the impact on the echo is small. Therefore, compared with coil A, the echo signal amplitude of coil B is reduced. Therefore, by comparing the signal amplitudes of coils A and B, it can be determined whether there is a crack.

[0079] When there are no cracks, Figure 7 As shown in the figure, the ultrasonic amplitudes generated by coil A and coil B are equal, and the thickness of the test piece can be calculated by the time difference between the excitation signal and the bottom surface reflected echo signal. When there is a crack parallel to coil B, such as Figure 8As shown, there is a crack with a width of 0.3 mm at the bottom. Since the polarization direction of the transverse wave generated by coil B is perpendicular to the crack direction, the presence of the crack causes significant scattering of the sound wave at the crack, and the echo energy is reduced. On the contrary, the polarization direction of the transverse wave generated by coil A is parallel to the crack direction. Since the size of the crack is small, the impact on the echo is small. Therefore, compared with coil A, the amplitude of the echo signal of coil B is reduced. If there is a crack on the surface of the test piece, the same phenomenon occurs. Therefore, by comparing the signal amplitudes of coils A and B, it can be determined whether there is a crack. In addition, compared with the signal of a traditional electromagnetic ultrasonic sensor, the present invention improves the transduction efficiency and signal-to-noise ratio of the electromagnetic ultrasonic sensor, such as Fig. 9 shown.

[0080] At the same time, the test piece is magnetized by the magnetic field of the permanent magnet 6. If there are no defects on the surface of the test piece, the magnetic flux is still confined within the test piece. However, if there are defects on the surface of the test piece, the magnetic field will leak into the surrounding air and will be detected by the three-axis Hall sensor 4. After the leakage magnetic signal is conditioned and processed by the data acquisition circuit 3, it will be transmitted to the computer for processing and display. Fig.10 As shown, the test piece is provided with defects of length x width x depth of 4x20x2 mm, 3x20x2 mm, 2x20x2 mm, and 1x20x2 mm. Due to the width limitation of the defects, three of the four three-axis Hall sensors detect the defects. It can be seen that the amplitude of the leakage magnetic signal increases with the increase of the defect.

[0081] In summary, the present invention makes full use of the advantages of electromagnetic ultrasound and magnetic flux leakage detection technology to achieve simultaneous detection of surface defects and internal defects of metal specimens, and also achieves the measurement of the thickness of metal specimens. In addition, a single permanent magnet structure is adopted to simplify the structural size and complexity, and the signal-to-noise ratio is improved through the design of orthogonal butterfly coils, thereby achieving crack detection.

Claims

1. An electromagnetic ultrasound and magnetic flux leakage composite detection device, characterized in that: It includes a permanent magnet, orthogonal butterfly coils, a three-axis Hall sensor, a leakage magnetic signal conditioning and data acquisition circuit, a signal generator, a power amplifier, a duplexer and a signal amplifier; The three-axis Hall sensor is arranged in front of the orthogonal butterfly coil, and the orthogonal butterfly coil is arranged below the permanent magnet; A signal generator, used for generating a pulse signal; A power amplifier, used to amplify the pulse signal; A duplexer for transmitting the amplified pulse signal to the orthogonal butterfly coil; A quadrature butterfly coil is used to excite a pair of orthogonal shear waves and generate a voltage signal based on the reflected echo; A signal amplifier, used to amplify and output the voltage signal generated by the orthogonal butterfly coil; Three-axis Hall sensor for detecting surrounding magnetic flux; The leakage magnetic signal conditioning and data acquisition circuit is used to condition and output the magnetic flux detected by the three-axis Hall sensor; The amplified voltage signal output by the signal amplifier is used to detect cracks and internal defects of the tested piece; the output data of the leakage magnetic signal conditioning and data acquisition circuit is used to detect surface defects of the tested piece.

2. The electromagnetic ultrasound and magnetic flux leakage composite detection device according to claim 1, characterized in that: The orthogonal butterfly coil is composed of two identical butterfly coils that are orthogonal to each other and are made through a flexible printed circuit board. The two coils are perpendicular to each other in the direction of current and shear force.

3. The electromagnetic ultrasound and magnetic flux leakage composite detection device according to claim 1, characterized in that: Copper foil is arranged between the orthogonal butterfly coil and the permanent magnet.

4. The electromagnetic ultrasound and magnetic flux leakage composite detection device according to claim 1, characterized in that: The permanent magnet is a cylindrical permanent magnet with a diameter of 25 mm and a height of 40 mm.

5. The electromagnetic ultrasound and magnetic flux leakage composite detection device according to claim 1, characterized in that: There are four three-axis Hall sensors arranged in a row, and the distance between two adjacent three-axis Hall sensors is 4 mm; the orthogonal butterfly coils are on the axes of the four three-axis Hall sensors.

6. The electromagnetic ultrasound and magnetic flux leakage composite detection device according to any one of claims 1 to 5, characterized in that: The vehicle body is also included. The three-axis Hall sensor and the orthogonal butterfly coil are all located at the bottom of the vehicle body, and wheels are arranged at the four corners of the bottom of the vehicle body.

7. A detection method based on the electromagnetic ultrasound and magnetic flux leakage composite detection device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Place the orthogonal butterfly coil in the electromagnetic ultrasound and magnetic flux leakage composite detection device above the test piece; S2, a pair of orthogonal shear waves are excited by the orthogonal butterfly coil, so that eddy currents are induced on the surface of the tested object, and ultrasonic waves are generated under the action of the magnetic field generated by the permanent magnet; S3, obtaining the voltage signal generated by the orthogonal butterfly coil, and respectively amplifying and outputting the voltage signals generated by the two coils in the orthogonal butterfly coil through a signal amplifier; S4, conditioning and outputting the magnetic flux detected by the three-axis Hall sensor through the magnetic leakage signal conditioning and data acquisition circuit; S5. Detect the thickness, cracks and internal defects of the tested piece through the amplified voltage signal output by the signal amplifier; detect the surface defects of the tested piece through the output data of the leakage magnetic signal conditioning and data acquisition circuit.

8. The detection method according to claim 7, characterized in that: The specific method of testing the tested piece in step S5 includes the following sub-steps: S5-1, determining whether the amplitudes of the signals after the voltages generated by the two coils are respectively amplified are the same, if so, determining that the tested piece has no cracks; otherwise, determining that the tested piece has cracks; and proceeding to step S5-2; S5-2, calculate the thickness of the test piece by the time difference between the excitation signal of the orthogonal butterfly coil and the reflected echo signal; determine whether there is a defect echo signal between the excitation signal of the orthogonal butterfly coil and the reflected echo signal, if so, determine that the test piece has an internal defect; otherwise, determine that the test piece has no internal defect; enter step S5-3; S5-3. Based on the output data of the leakage magnetic signal conditioning and data acquisition circuit, determine whether the three-axis Hall sensor detects a magnetic flux greater than the set threshold. If so, it is determined that the test piece has surface defects; otherwise, it is determined that the test piece does not have surface defects.

9. The detection method according to claim 7 or 8, characterized in that: Step S5 is followed by the following steps: S6. Process the output data of the leakage magnetic signal conditioning and data acquisition circuit by a computer to obtain the defect size of the tested piece; and display the output of the signal amplifier by an oscilloscope.

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