An internal and external defect passive magnetic identification method and device, electronic equipment and storage medium

Abstract

The present application relates to the technical field of electromagnetic nondestructive testing, and provides an internal and external defect passive magnetic identification method and device, electronic equipment and storage medium, comprising: an internal and external defect passive magnetic identification method without connecting any current, voltage and magnetic field excitation in addition to a magnetic flux leakage detection main magnetizer; a detection device based on the above method, an implementation method, a signal processing method for processing collected signals and identifying internal and external wall defects, and related electronic equipment and storage medium. The present application can effectively distinguish internal and external wall defects in magnetic flux leakage detection, simplify the structure and circuit of existing magnetic flux leakage detection equipment, and reduce the noise source polluting the magnetic flux leakage detection signal.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic nondestructive testing, and in particular to a method, device, electronic equipment and storage medium for passive magnetic identification of internal and external defects. Background Art

[0002] Oil and gas energy is a key pillar of national economic development. Pipelines and tanks used to transport and store oil and gas products are primarily manufactured from ferromagnetic materials. Ferromagnetic materials offer a long service life, and regular maintenance is essential for safety. Magnetic flux leakage testing (MFL) is the most commonly used method for inspecting ferromagnetic materials. Evaluating inspected components based on test results and replacing or repairing them accordingly are crucial measures for ensuring safe operation and extending their service life. Defect location in the inspection report is a crucial indicator for repairs. Because the MFL detection signal waveforms for defects on the inner and outer walls are similar, they cannot be used to distinguish between defects on the inner and outer walls. Therefore, additional inspection systems are generally required to identify and distinguish defects on the inner and outer walls.

[0003] Current methods for detecting and identifying internal and external wall defects using magnetic flux leakage (MFL) testing primarily rely on applying electric or magnetic fields to induce eddy currents on the inner wall of the test object. Taking advantage of the significant perturbation of these eddy currents by inner wall defects, eddy current detection coils are used to detect abnormal eddy current signals from the inner wall. This abnormality in the eddy current signals is then used to identify inner wall defects, thereby distinguishing inner wall defects from outer wall defects. To prevent contamination of the MFL detection signal by the applied electric or magnetic field, a common practice is to place an eddy current detection structure some distance away from the MFL detection structure. Within this eddy current detection structure, coils are used to apply alternating current excitation, inducing eddy currents on the inner wall of the test object, thereby detecting and identifying inner wall defects. This approach results in a large and complex structure for MFL testing equipment, increasing manufacturing and operating costs. In recent years, patents have also proposed simplifying the structure of MFL testing equipment by adding a magnetic field to the MFL detection module to induce motional eddy currents on the inner wall of the test object, thereby identifying inner wall defects. However, this method adds magnetic field excitation and is affected by changes in operating conditions such as detection lift-off. Its distance from the leakage magnetic field detection sensor is close and unstable, and the induced eddy current is also unstable, resulting in greater pollution to the leakage magnetic field detection signal, thereby weakening the accuracy of leakage magnetic field detection. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for passive magnetic identification of internal and external defects, comprising:

[0005] Based on the conventional magnetic flux leakage detection method, the eddy current effect is used. An eddy current detection sensor is set near the contact surface between the loop-type magnetization device and the component to be detected. The eddy current detection sensor is used to pick up the motional eddy current signal induced by the loop-type magnetization device on the inner wall surface of the component to be detected, and determine the type of defects on the inner and outer walls.

[0006] The eddy current detection sensor does not need to apply any current or voltage excitation for exciting a magnetic field; except for the main magnetizer in the loop type magnetizing device, no further magnetic field excitation needs to be applied.

[0007] Preferably, the specific steps for determining the types of inner and outer wall defects are:

[0008] S1: The passive magnetic identification device for inner and outer wall defects is placed close to the inner wall of the component to be inspected. Driven by an external force, the passive magnetic identification device for inner and outer wall defects moves relative to the inner wall surface of the component to be inspected, and the magnet in the passive magnetic identification device for inner and outer wall defects is used to magnetize the component to be inspected;

[0009] S2: During the movement of the passive magnetic identification device for inner and outer wall defects, based on the same clock, the eddy current detection sensor therein collects eddy current signals from the surface of the component to be detected, and the magnetic flux leakage detection sensor therein collects leakage magnetic field signals from the surface of the component to be detected, and the above signals are stored in the hard disk;

[0010] S3: The signal analysis unit reads the magnetic field leakage signal and eddy current signal of the component to be inspected in the hard disk, and identifies and extracts the position coordinates of all defects contained in the component to be inspected from the magnetic field leakage signal. Using these position coordinates, the eddy current signal of the defect at the corresponding position is extracted from the eddy current signal based on the fixed position difference between the eddy current detection sensor and the magnetic field leakage detection sensor.

[0011] S4: Based on a pre-calibrated inner wall defect eddy current identification threshold, the signal analysis unit compares the defect eddy current signal obtained in S3 with the threshold, and identifies defects with defect eddy current signals higher than the threshold as inner wall defects, and defects with defect eddy current signals lower than the threshold as outer wall defects.

[0012] Preferably, the inner wall defect eddy current identification threshold calibration step in step S4 is specifically as follows:

[0013] S411: Based on the minimum inner wall defect size to be identified in the component to be inspected, a calibration piece containing the minimum inner wall defect is made of the same material as the component to be inspected; a magnetization device is used to simulate the actual inspection working conditions to collect and save the eddy current signal Vc of the calibration piece = {Vc1, Vc2, ... Vc s}, s is the data length of the Vc signal;

[0014] S412: The length of the eddy current signal data at the defect position in the marked component is m. m is calculated based on the defect length l, the sampling frequency f of the passive magnetic identification device for internal and external defects, and the movement speed v. The calculation formula is:

[0015]

[0016] Among them, the unit of defect length dimension l is millimeter, the unit of sampling frequency f is Hz, and the unit of motion speed v is mm / s;

[0017] S413: Perform moving average on the eddy current signal Vc with a period of m to obtain the average eddy current signal of the calibration part The calculation formula is as follows:

[0018]

[0019] Where i represents the data point number of the average eddy current signal of the calibration part;

[0020] S414: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal Vc of the calibration part f ={Vc fj}, the calculation formula is as follows:

[0021]

[0022] Wherein, j represents the data point number of the average differential eddy current signal of the calibration part;

[0023] S415: Average differential eddy current signal Find the absolute value, The maximum value is set as the threshold w.

[0024] Preferably, the steps of determining internal and external defects in step S4 are specifically as follows:

[0025] S421: extracting the eddy current signal Vk of each defect in step S3, where k=1, 2, ..., g, where k is the number of defects in the component to be inspected, and g is the total number of defects in the component to be inspected;

[0026] S422: Extract the eddy current signal Vk={Vk1, Vk2, ... Vk z Perform a moving average calculation with a period of m, where z is the data length of the eddy current signal of defect k; m is the data length of the eddy current signal at the defect position in the calibration part. Obtain the average eddy current signal of defect k

[0027] S423: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal of defect k

[0028] S424: Average differential eddy current signal Vk for defect K f After finding the absolute value, compare it with the threshold w point by point. If |Vk f If there is a point greater than the threshold w, it is an inner wall defect, otherwise it is an outer wall defect;

[0029] S425: After the identification of defect number k is completed, S421-S424 are repeated to determine the surface position of defect number k+1 until the types of all defects of the component to be inspected are determined.

[0030] A passive magnetic identification device for internal and external wall defects, used to implement the above-mentioned passive magnetic identification method for internal and external defects, comprising: a component to be detected, a loop-type magnetization device, an eddy current detection sensor, and a magnetic flux leakage detection sensor; wherein:

[0031] The loop type magnetizing device uses a permanent magnet or a DC electromagnet to make the main magnetizer of the loop, which is used to provide magnetizing excitation and form N and S magnetic poles at both ends of the magnetizing device;

[0032] The loop type magnetization device is installed on a wall surface of the component to be detected, which wall surface is the inner wall of the component to be detected;

[0033] The N and S magnetic poles of the loop-type magnetizing device are installed in contact with the inner wall of the component to be detected, forming a connected and closed main magnetizing circuit between the loop-type magnetizing device and the component to be detected; the contact surface between the inner wall of the component to be detected and the N and S magnetic poles of the loop-type magnetizing device is the contact surface;

[0034] The loop-type magnetizing device keeps in contact with the component to be detected, and when relative motion parallel to the contact surface occurs, the loop-type magnetizing device induces motional eddy currents near the contact surface between the two.

[0035] The eddy current detection sensor and the loop-type magnetizing device are installed on the same side, close to the contact surface between the component to be detected and the magnetizing device, and receive the motional eddy current signal induced by the loop-type magnetizing device near the contact surface of the inner wall of the component to be detected;

[0036] The eddy current detection sensor does not require any external current or voltage excitation for exciting the magnetic field. In addition to the main magnetizer of the loop type magnetizing device, no additional magnetizing excitation is required.

[0037] The magnetic flux leakage detection sensor is installed on the inner wall side of the component to be detected, close to the inner wall of the component to be detected, close to the symmetrical center position of the two magnetic poles of the loop type magnetizing device, and maintains a fixed relative position with the loop type magnetizing device and the eddy current detection sensor.

[0038] Preferably, it further includes a signal analysis unit;

[0039] The signal analysis unit analyzes and processes the eddy current signal of the component to be inspected, identifies internal defects, and distinguishes between internal and external defects.

[0040] An electronic device for passive magnetic identification of internal and external wall defects comprises: a processor and a storage device; the processor loads and executes instructions and data in the storage device to implement the passive magnetic identification method of internal and external defects.

[0041] A storage medium for passive magnetic identification of inner and outer wall defects, wherein the storage device stores instructions and data for implementing a method for passive magnetic identification of inner and outer defects.

[0042] The present invention has the following beneficial effects:

[0043] 1. The present invention provides a method, device, electronic device, and storage medium for identifying inner wall defects and distinguishing between inner and outer wall defects by utilizing the motional eddy current signals induced by a magnetic flux leakage detection main magnetizer on the inner wall surface of the object being inspected. This method can simply and effectively identify and distinguish between inner and outer wall defects of the object being inspected.

[0044] 2. The magnetic flux leakage detection system utilizes the motional eddy current effect of the main magnetizer. It does not require any external current or voltage excitation for exciting the magnetic field, nor does it require any magnetizing excitation. It can be effectively used to distinguish internal and external wall defects in magnetic flux leakage detection, simplifying the structure and circuit of existing magnetic flux leakage detection equipment and facilitating the lightweighting and miniaturization of related equipment.

[0045] 3. In addition to the main magnetizer, no external magnetic field excitation or electric field excitation is required to stimulate the magnetic field, which significantly reduces the disturbance of the leakage magnetic field detection signal caused by the external excitation in the existing method, reduces the noise source, and improves the signal-to-noise ratio of the leakage magnetic field detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the average differential eddy current signal of the calibration part;

[0047] Figure 2 Schematic diagram of the average differential eddy current signal of the first type of defect;

[0048] Figure 3 Schematic diagram of the average differential eddy current signal of the second type of defect;

[0049] Figure 4 This is a structural diagram of the passive magnetic identification device for inner and outer wall defects;

[0050] 1000-loop type magnetizing device;

[0051] Figure 5 This is a first embodiment of a loop-type magnetizing device;

[0052] 100 - first magnetic steel brush, 200 - first permanent magnet, 300 - magnetic yoke, 400 - magnetic flux leakage detection sensor, 500 - eddy current detection sensor, 600 - pipe wall of the component to be detected, 700 - magnetizing circuit, 800 - second permanent magnet, 900 - second magnetic steel brush;

[0053] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0054] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] The present invention provides a method for passive magnetic identification of internal and external defects, comprising:

[0056] Based on the conventional magnetic flux leakage detection method, the eddy current effect is used. An eddy current detection sensor is set near the contact surface between the loop-type magnetization device and the component to be detected. The eddy current detection sensor is used to pick up the motional eddy current signal induced by the loop-type magnetization device on the inner wall surface of the component to be detected, and determine the type of defects on the inner and outer walls.

[0057] The eddy current detection sensor does not need to apply any current or voltage excitation for exciting a magnetic field; except for the main magnetizer in the loop type magnetizing device, no further magnetic field excitation needs to be applied.

[0058] Furthermore, the specific steps for determining the types of inner and outer wall defects are as follows:

[0059] S1: The passive magnetic identification device for inner and outer wall defects is placed close to the inner wall of the component to be inspected. Driven by an external force, the passive magnetic identification device for inner and outer wall defects moves relative to the inner wall surface of the component to be inspected, and the magnet in the passive magnetic identification device for inner and outer wall defects is used to magnetize the component to be inspected;

[0060] S2: During the movement of the passive magnetic identification device for inner and outer wall defects, based on the same clock, the eddy current detection sensor therein collects eddy current signals from the surface of the component to be detected, and the magnetic flux leakage detection sensor therein collects leakage magnetic field signals from the surface of the component to be detected, and the above signals are stored in the hard disk;

[0061] S3: The signal analysis unit reads the magnetic field leakage signal and eddy current signal of the component to be inspected in the hard disk, and identifies and extracts the position coordinates of all defects contained in the component to be inspected from the magnetic field leakage signal. Using these position coordinates, the eddy current signal of the defect at the corresponding position is extracted from the eddy current signal based on the fixed position difference between the eddy current detection sensor and the magnetic field leakage detection sensor.

[0062] S4: Based on a pre-calibrated inner wall defect eddy current identification threshold, the signal analysis unit compares the defect eddy current signal obtained in S3 with the threshold, and identifies defects with defect eddy current signals higher than the threshold as inner wall defects, and defects with defect eddy current signals lower than the threshold as outer wall defects.

[0063] Furthermore, the inner wall defect eddy current identification threshold calibration step in step S4 is specifically as follows:

[0064] S411: Based on the minimum inner wall defect size to be identified in the component to be inspected, a calibration piece containing the minimum inner wall defect is made of the same material as the component to be inspected; a magnetization device is used to simulate the actual inspection working conditions to collect and save the eddy current signal Vc of the calibration piece = {Vc1, Vc2, ... Vc s}, s is the data length of the Vc signal;

[0065] S412: The length of the eddy current signal data at the defect position in the marked component is m. m is calculated based on the defect length l, the sampling frequency f of the passive magnetic identification device for internal and external defects, and the movement speed v. The calculation formula is:

[0066]

[0067] Among them, the unit of defect length dimension l is millimeter, the unit of sampling frequency f is Hz, and the unit of motion speed v is mm / s;

[0068] S413: Perform moving average on the eddy current signal Vc with a period of m to obtain the average eddy current signal of the calibration part The calculation formula is as follows:

[0069]

[0070] Where i represents the data point number of the average eddy current signal of the calibration part;

[0071] S414: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal of the calibration part The calculation formula is as follows:

[0072]

[0073] Wherein, j represents the data point number of the average differential eddy current signal of the calibration part;

[0074] Specifically, the average differential eddy current signal of the calibration piece is as follows: Figure 1 As shown;

[0075] S415: Average differential eddy current signal Find the absolute value, The maximum value is set as the threshold w;

[0076] Specifically, for example, if the defect depth of the calibration part is 6.67% wt, the maximum value 2.1 of the average differential eddy current signal is found as the threshold value w.

[0077] Furthermore, the steps of determining internal and external defects in step S4 are specifically as follows:

[0078] S421: extracting the eddy current signal Vk of each defect in step S3, where k=1, 2, ..., g, where k is the number of defects in the component to be inspected, and g is the total number of defects in the component to be inspected;

[0079] S422: Extract the eddy current signal Vk={Vk1, Vk2, ... Vk z Perform a moving average calculation with a period of m, where z is the data length of the eddy current signal of defect k; m is the data length of the eddy current signal at the defect position in the calibration part. Obtain the average eddy current signal of defect k

[0080] S423: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal of defect k

[0081] S424: Average differential eddy current signal Vk for defect K f After finding the absolute value, compare it with the threshold w point by point. If |Vk f If there is a point greater than the threshold w, it is an inner wall defect, otherwise it is an outer wall defect;

[0082] Specifically, for example, the value of the threshold w is 2.1, such as Figure 2 The absolute value of the average differential eddy current signal of the first type of defect shown in is greater than 2.1, so the first type of defect is an inner wall defect; Figure 3 The absolute values ​​of the average differential eddy current signals of the second type of defects shown are all less than 2.1, so the second type of defects are outer wall defects;

[0083] S425: After the identification of defect number k is completed, S421-S424 are repeated to determine the surface position of defect number k+1 until the types of all defects of the component to be inspected are determined.

[0084] refer to Figure 4 The present invention provides a passive magnetic identification device for internal and external wall defects, which is used to implement the above-mentioned passive magnetic identification method for internal and external defects, including: a component to be detected, a loop-type magnetization device, an eddy current detection sensor and a magnetic flux leakage detection sensor; wherein:

[0085] The loop type magnetizing device uses a permanent magnet or a DC electromagnet to make the main magnetizer of the loop, which is used to provide magnetizing excitation and form N and S magnetic poles at both ends of the magnetizing device;

[0086] The loop type magnetization device is installed on a wall surface of the component to be detected, which wall surface is the inner wall of the component to be detected;

[0087] The N and S magnetic poles of the loop-type magnetizing device are installed in contact with the inner wall of the component to be detected, forming a connected and closed main magnetizing circuit between the loop-type magnetizing device and the component to be detected; the contact surface between the inner wall of the component to be detected and the N and S magnetic poles of the loop-type magnetizing device is the contact surface;

[0088] The loop-type magnetizing device keeps in contact with the component to be detected, and when relative motion parallel to the contact surface occurs, the loop-type magnetizing device induces motional eddy currents near the contact surface between the two.

[0089] The eddy current detection sensor and the loop-type magnetizing device are installed on the same side, close to the contact surface between the component to be detected and the magnetizing device, and receive the motional eddy current signal induced by the loop-type magnetizing device near the contact surface of the inner wall of the component to be detected;

[0090] The eddy current detection sensor does not require any external current or voltage excitation for exciting the magnetic field. In addition to the main magnetizer of the loop type magnetizing device, no additional magnetizing excitation is required.

[0091] The magnetic flux leakage detection sensor is installed on the inner wall side of the component to be detected, close to the inner wall of the component to be detected, close to the symmetrical center position of the two magnetic poles of the loop type magnetizing device, and maintains a fixed relative position with the loop type magnetizing device and the eddy current detection sensor.

[0092] Specifically, the loop-type magnetizer is shaped like a U or C loop. Its installation location varies depending on the application scenario. For tubular components, the loop-type magnetizer can be mounted on either the inner or outer wall of the tubular structure. For plate-shaped components, the loop-type magnetizer can be mounted on the surface. The mounting side of the magnetizer corresponds to the inner wall described in this invention. The eddy current sensor is positioned 10-20 mm from the contact surface between the component and the magnetizer.

[0093] The loop type magnetization device can be designed according to the application scenario, refer to Figure 5 In the first embodiment of the present invention, the loop type magnetization device includes: a first magnetic conductive steel brush 100, a first permanent magnet 200, a magnetic conductive yoke 300, a second permanent magnet 800 and a second magnetic conductive steel brush 900;

[0094] One end of the first magnetic conductive steel brush and one end of the second magnetic conductive steel brush are movably arranged on the inner surface of the component to be detected;

[0095] The other end of the first magnetic conductive steel brush is fixedly connected to one end of the first permanent magnet, and the other end of the second magnetic conductive steel brush is fixedly connected to one end of the second permanent magnet;

[0096] One end of the magnetic yoke is fixedly connected to the other end of the first permanent magnet, and the other end of the magnetic yoke is fixedly connected to the other end of the second permanent magnet;

[0097] The first magnetic steel brush, the second magnetic steel brush, the first permanent magnet, the second permanent magnet and the magnetic yoke form an inverted U-shaped structure, wherein the N and S poles of the first permanent magnet and the second permanent magnet are connected in series to form the main magnetizer of the loop type magnetization device.

[0098] In practical applications, the magnetic steel brushes (100, 900) and the magnetic yoke iron are not necessary components, but are optional and have an OR-inclusive relationship. Figure 5 The magnetic circuit composed of the first magnetic steel brush 100, the first permanent magnet 200, the magnetic yoke 300, the second permanent magnet 800, the second magnetic steel brush 900 and the pipe wall 600 of the component to be detected can also be simplified to consist of a permanent magnet as the main magnetizer and the pipe wall 600 of the component to be detected.

[0099] By installing the eddy current detection sensor close to the side of the first permanent magnet and close to the surface of the component to be tested, the strength of the eddy current signal picked up by the eddy current detection sensor can be effectively enhanced. The number of turns of the eddy current detection sensor is 100.

[0100] The moving eddy current detection sensor senses the eddy current caused by the magnetic field signal of the pipe wall of the component to be detected. In the absence of defects, the magnetic field on the surface of the ferromagnetic material does not leak, and the magnetic flux φ of the eddy current detection sensor changes only slightly. At the defect, the motional eddy current generates disturbances, the magnetic field strength suddenly increases, and the magnetic flux φ in the eddy current detection sensor changes. Based on Faraday's law of electromagnetic induction, the eddy current detection sensor generates an induced electromotive force, which is calculated as follows:

[0101]

[0102] Among them, the displacement of the eddy current detection sensor through the pipe wall per unit time t is s, and it can be known from the velocity calculation formula:

[0103]

[0104] Combining equations (1) and (2), we can obtain:

[0105]

[0106] From formula (3), we can know that the magnitude of the induced electromotive force generated by the eddy current detection sensor is related to the number of coil turns N, the moving speed v, and the rate of change of the magnetic flux. The rate of change of magnetic flux is mainly related to the change of magnetic field on the surface of ferromagnetic material in different detection areas.

[0107] Furthermore, it also includes a signal analysis unit;

[0108] The signal analysis unit analyzes and processes the eddy current signal of the component to be inspected, identifies internal defects, and distinguishes between internal and external defects.

[0109] The present invention provides an electronic device for passive magnetic identification of internal and external wall defects, comprising: a processor and a storage device; the processor loads and executes instructions and data in the storage device to implement the above-mentioned method for passive magnetic identification of internal and external defects.

[0110] The present invention provides a storage medium for passive magnetic identification of inner and outer wall defects. The storage device stores instructions and data for implementing the above-mentioned method for passive magnetic identification of inner and outer defects.

[0111] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0112] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same item of hardware. The use of the terms first, second, and third, etc., does not denote any order and should be construed as identifiers.

[0113] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A passive magnetic identification method for internal and external defects, characterized in that: include: Based on the conventional magnetic flux leakage detection method, the eddy current effect is used. An eddy current detection sensor is set near the contact surface between the loop-type magnetization device and the component to be detected. The eddy current detection sensor is used to pick up the motional eddy current signal induced by the loop-type magnetization device on the inner wall surface of the component to be detected, and determine the type of defects on the inner and outer walls. The eddy current detection sensor does not require any current or voltage excitation for exciting a magnetic field; except for the main magnetizer in the loop-type magnetizing device, no further magnetic field excitation is required; The specific steps to determine the types of inner and outer wall defects are: S1: The passive magnetic identification device for inner and outer wall defects is placed close to the inner wall of the component to be inspected. Driven by an external force, the passive magnetic identification device for inner and outer wall defects moves relative to the inner wall surface of the component to be inspected, and the magnet in the passive magnetic identification device for inner and outer wall defects is used to magnetize the component to be inspected; S2: During the movement of the passive magnetic identification device for inner and outer wall defects, based on the same clock, the eddy current detection sensor therein collects eddy current signals from the surface of the component to be detected, and the magnetic flux leakage detection sensor therein collects leakage magnetic field signals from the surface of the component to be detected, and the above signals are stored in the hard disk; S3: The signal analysis unit reads the magnetic field leakage signal and eddy current signal of the component to be inspected in the hard disk, and identifies and extracts the position coordinates of all defects contained in the component to be inspected from the magnetic field leakage signal. Using these position coordinates, the eddy current signal of the defect at the corresponding position is extracted from the eddy current signal based on the fixed position difference between the eddy current detection sensor and the magnetic field leakage detection sensor. S4: The signal analysis unit compares the defect eddy current signal obtained in S3 with the threshold value based on a pre-calibrated inner wall defect eddy current identification threshold value, and identifies defects with defect eddy current signals higher than the threshold value as inner wall defects, and defects with defect eddy current signals lower than the threshold value as outer wall defects; The inner wall defect eddy current identification threshold calibration step in step S4 is specifically as follows: S411: Based on the minimum inner wall defect size to be identified in the component to be inspected, a calibration piece containing the minimum inner wall defect is made of the same material as the component to be inspected; a magnetization device is used to simulate the actual inspection working conditions to collect and save the eddy current signal Vc of the calibration piece = {Vc1, Vc2, ... Vc s }, s is the data length of the Vc signal; S412: The length of the eddy current signal data at the defect position in the marked component is m. m is calculated based on the defect length l, the sampling frequency f of the passive magnetic identification device for internal and external defects, and the movement speed v. The calculation formula is: Among them, the unit of defect length dimension l is millimeter, the unit of sampling frequency f is Hz, and the unit of motion speed v is mm / s; S413: Perform moving average on the eddy current signal Vc with a period of m to obtain the average eddy current signal of the calibration part The calculation formula is as follows: Where i represents the data point number of the average eddy current signal of the calibration part; S414: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal Vc of the calibration part f ={Vc fj }, the calculation formula is as follows: Wherein, j represents the data point number of the average differential eddy current signal of the calibration part; S415: Average differential eddy current signal Vc f To find the absolute value, use |Vc f The maximum value among them is set as the threshold w.

2. The passive magnetic identification method for internal and external defects according to claim 1, characterized in that: The steps for determining internal and external defects in step S4 are specifically as follows: S421: extracting the eddy current signal Vk of each defect in step S3, where k=1, 2, ..., g, where k is the number of defects in the component to be inspected, and g is the total number of defects in the component to be inspected; S422: Extract the eddy current signal Vk={Vk1, Vk2, ... Vk z Perform a moving average calculation with a period of m, where z is the data length of the eddy current signal of defect k; m is the data length of the eddy current signal at the defect position in the calibration part; obtain the average eddy current signal of defect k S423: Average eddy current signal Calculate the difference and obtain the average differential eddy current signal of defect k S424: Average differential eddy current signal Vk for defect K f After finding the absolute value, compare it with the threshold w point by point. If |Vk f If there is a point greater than the threshold w, it is an inner wall defect, otherwise it is an outer wall defect; S425: After the identification of defect number k is completed, S421-S424 are repeated to determine the surface position of defect number k+1 until the types of all defects of the component to be inspected are determined.

3. A passive magnetic identification device for internal and external wall defects, used to implement the passive magnetic identification method for internal and external defects according to any one of claims 1 to 2, characterized in that: include: A component to be detected, a loop-type magnetizing device, an eddy current detection sensor, and a magnetic flux leakage detection sensor; wherein: The loop type magnetizing device uses a permanent magnet or a DC electromagnet to make the main magnetizer of the loop, which is used to provide magnetizing excitation and form N and S magnetic poles at both ends of the magnetizing device; The loop type magnetization device is installed on a wall surface of the component to be detected, which wall surface is the inner wall of the component to be detected; The N and S magnetic poles of the loop-type magnetizing device are installed in contact with the inner wall of the component to be detected, forming a connected and closed main magnetizing circuit between the loop-type magnetizing device and the component to be detected; the contact surface between the inner wall of the component to be detected and the N and S magnetic poles of the loop-type magnetizing device is the contact surface; The loop-type magnetizing device keeps in contact with the component to be detected, and when relative motion parallel to the contact surface occurs, the loop-type magnetizing device induces motional eddy currents near the contact surface between the two. The eddy current detection sensor and the loop-type magnetizing device are installed on the same side, close to the contact surface between the component to be detected and the magnetizing device, and receive the motional eddy current signal induced by the loop-type magnetizing device near the contact surface of the inner wall of the component to be detected; The eddy current detection sensor does not require any external current or voltage excitation for exciting the magnetic field. In addition to the main magnetizer of the loop type magnetizing device, no additional magnetizing excitation is required. The magnetic flux leakage detection sensor is installed on the inner wall side of the component to be detected, close to the inner wall of the component to be detected, close to the symmetrical center position of the two magnetic poles of the loop type magnetizing device, and maintains a fixed relative position with the loop type magnetizing device and the eddy current detection sensor; Also included is a signal analysis unit; The signal analysis unit analyzes and processes the eddy current signal of the component to be inspected, identifies internal defects, and distinguishes between internal and external defects.

4. An electronic device for passive magnetic identification of inner and outer wall defects, characterized in that: include: A processor and a storage device; the processor loads and executes instructions and data in the storage device to implement any one of the passive magnetic identification methods for internal and external defects described in claims 1 to 2.

5. A passive magnetic identification storage medium for inner and outer wall defects, characterized in that: The storage medium stores instructions and data for implementing any one of the internal and external defect passive magnetic identification methods described in claims 1 to 2.

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