Defect depth detection method based on magnet magnetic force

Abstract

The invention discloses a defect depth detection method based on magnet magnetic force, which comprises the following steps of: detecting the magnetic attraction force of an electromagnet on a detected piece in the process that the electromagnet moves along the ferromagnetic detected piece by using a detection sensor fixed on the electromagnet; and calculating the defect depth value of the surface of the detected piece according to the relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the detected piece. By utilizing the relationship between the magnetic attraction force value and the defect depth, the defect depth of the surface of the detected piece is obtained by collecting the magnetic attraction force value at the defect, and then whether maintenance is needed or not can be judged according to the detection result, so that the operation safety of the detected piece is effectively guaranteed.

Description

Technical Field

[0001] This invention relates to the field of defects in ferromagnetic materials. More specifically, this invention relates to a method for detecting defect depth based on the magnetic force of a magnet. Background Technology

[0002] As crucial carriers of energy and resources, ferromagnetic pipes and other materials are widely used in oil and natural gas transportation, water supply, and drainage. However, with increasing usage time and the complex influence of the environment, these materials face problems such as aging, corrosion, and external damage, leading to frequent accidents such as leaks and ruptures. This not only causes huge economic losses but may also lead to serious consequences such as environmental pollution and personal injury. Defect detection of ferromagnetic pipes and other materials can not only promptly identify potential safety hazards and take preventative measures to prevent accidents but also help optimize maintenance plans and reduce operation and maintenance costs. Simultaneously, this detection work can ensure the stable transmission of energy and resources, maintain the normal order of social production and life, and play an important role in promoting sustainable economic development and protecting the ecological environment. In existing technologies, devices that utilize the properties of ferromagnetic materials for detection can typically only locate the defect but cannot determine its depth. To solve this problem, it is necessary to provide a defect depth detection method based on the magnetic force of a magnet. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0004] To achieve these objectives and other advantages of the present invention, a defect depth detection method based on magnetic force is provided, comprising: using a detection sensor fixed to an electromagnet, detecting the magnitude of the magnetic attraction force of the electromagnet on the workpiece as the electromagnet moves along the ferromagnetic workpiece, and calculating the defect depth value of the surface of the workpiece based on the relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the workpiece.

[0005] Preferably, the relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the workpiece being tested is expressed by the following formula: In the above formula, F is the magnetic attraction force, µ0 is the vacuum permeability, K is the number of coil turns, I is the current, V is the volume of space occupied by the electromagnetic field, Φ is the magnetic flux, d1 is the distance between the electromagnet and the surface of the workpiece to be inspected, which is determined according to the inspection requirements; d2 is the defect depth.

[0006] Preferably, the electromagnet is fixed to the non-ferromagnetic housing on the side facing the object being tested, and the side of the housing facing the object being tested is also provided with a walking device to drive the housing to move along the object being tested; each electromagnet has multiple detection sensors arranged in a quincunx pattern on the side facing the object being tested.

[0007] Preferably, the housing contains a data processing module and a data storage module, and the detection sensor, the data processing module, and the data storage module are sequentially and communicatively connected.

[0008] Preferably, a plurality of electromagnets are uniformly arranged on the side of the housing facing the object being tested, and the magnetic field direction of each electromagnet is the same.

[0009] Preferably, the detection sensor is a strain gauge force sensor.

[0010] Preferably, the component to be tested is a pipe, and the housing is annular. The housing is fitted onto the component to be tested to detect defects on the outer circumferential surface of the component.

[0011] Preferably, the component being tested is a pipe, and the housing is annular, disposed inside the component being tested to detect defects on the inner wall of the component being tested.

[0012] Preferably, the part to be tested has a plate-shaped structure, the length of the housing is the same as the width of the part to be tested, and the walking device drives the housing to move longitudinally along the part to be tested.

[0013] Preferably, the walking device includes a drive motor and multiple wheels, each wheel being rotatably connected to the housing via a shaft, the drive motor being connected to the shaft of one or more wheels via a transmission device to drive the wheels to rotate; an encoder is provided on the shaft of one of the wheels.

[0014] The present invention has at least the following beneficial effects: 1. The defect depth detection method based on magnetic force provided by the present invention utilizes the relationship between magnetic attraction value and defect depth. By collecting the magnetic attraction value at the defect, the defect depth on the surface of the tested part can be obtained. Then, the test results can be used to determine whether repair is required, effectively ensuring the operational safety of the tested part.

[0015] 2. The defect depth detection method based on magnetic force provided by the present invention uses an electromagnet fixedly mounted on a housing. The shape of the housing can be selected according to the shape of the part being tested, thus making it applicable to surface defects of parts with different shapes.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0017] Figure 1 This is a side view of the housing when the tested component is a plate-shaped structure, as described in this invention. Figure 2 This is a curve showing the relationship between the magnetic attraction force and the defect depth in this invention; Figure 3 This is a side view of the structure of the tested component in this invention, where the housing is located outside the tested component; Figure 4 This is a side view of the structure when the component under test in the invention is a pipe and the housing is located inside the component under test. Figure 5 This is a side view of the structure when the object to be tested in this invention is a pipe, the housing is located outside the object to be tested, and only one row of the detection sensors is provided on the electromagnet. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0019] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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.

[0020] like Figure 1 As shown, the present invention provides a defect depth detection method based on the magnetic force of a magnet, comprising: using a detection sensor 4 fixed on an electromagnet 3, detecting the magnitude of the magnetic attraction force of the electromagnet 3 on the test piece 5 as the electromagnet 3 moves along the ferromagnetic test piece 5, and calculating the defect depth value on the test piece 5 based on the relationship between the magnetic attraction force and the distance between the electromagnet 3 and the surface of the test piece 5.

[0021] In this technical solution, the surface defects on the tested component 5 are detected based on changes in magnetic attraction force. Specifically, when a deep defect exists on the surface of the tested component 5, the magnetic attraction force value collected by the detection sensor 4 decreases. The magnetic attraction force between the electromagnet 3 and the tested component 5 can be expressed as: (1) In equation (1), F is the magnetic attraction force between the electromagnet and the object being tested; µ0 is the free magnetic permeability, with a value of A / M; d is the distance between the electromagnet 3 and the bottom of the defect; E is the magnetic energy volume, a constant related to the electromagnet's own performance; M is the magnetic moment, a constant related to the electromagnet's own performance.

[0022] The distance d between the electromagnet 3 and the bottom of the defect can be expressed as: (2) In formula (2), is the lift-off value, which is the distance between the electromagnet 3 and the surface of the tested part 5. It is determined according to the testing needs and is a fixed value; is the defect depth.

[0023] The magnetic energy volume E can be expressed as: (3) In equation (3), K is the number of coil turns, I is the current, and V is the volume of space occupied by the electromagnetic field.

[0024] The magnitude of the magnetic moment M depends on the magnetism and magnitude of the magnet: (4) In equation (4), Φ is the magnetic flux value. When the electromagnet is selected, both K and Φ are constants.

[0025] Therefore, formula (1) can be written as: (5) From equation (5), the relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the workpiece being tested can be obtained as follows: (6) (7) According to equations (6) and (7), S is a constant related to the performance of the electromagnet itself. Only the defect depth d2 and the magnetic attraction force F are unknowns. Therefore, after the detection sensor 4 detects the magnetic attraction force of the electromagnet 3 on the tested part 5, the value of the defect depth d2 can be calculated using equation (6). As an example, Figure 2 The figure shows the relationship curve between the magnetic attraction force F and the defect depth d2 when d1 is 1 mm. The two are in one-to-one correspondence. The defect depth d2 on the surface of the tested part 5 can be accurately calculated based on the F value detected by the detection sensor 4.

[0026] In another technical solution, the electromagnet 3 is fixed to the side of the non-ferromagnetic housing 1 facing the workpiece 5, and the side of the housing 1 facing the workpiece 5 is also provided with a traveling device 2 to drive the housing 1 to move along the workpiece 5; multiple detection sensors 4 are evenly arranged on the side of each electromagnet 3 facing the workpiece 5. The housing 1 is made of non-ferromagnetic material, and the intensity of the electromagnet 3 can be adjusted according to the material and properties of different workpieces to be inspected and the needs of on-site inspection. Multiple detection sensors 4 are evenly arranged on each electromagnet 3 to ensure that the detection sensors 4 can cover the surface of the workpiece 5 within a unit stroke, increasing the detection area.

[0027] In another technical solution, a data processing module and a data storage module are provided inside the housing 1, and the detection sensor 4, the data processing module, and the data storage module are sequentially and communicatively connected. The data processing module includes an A / D converter and a signal filter. The A / D converter module is used to perform analog-to-digital conversion on the data collected by the detection sensor 5, and the signal filter is used to filter out noise and interference. The data storage module is used to store the data collected by the detection sensor 4 and processed by the data processing module, so as to carry out data analysis after the detection is completed. A power supply component is also provided inside the housing 1 to supply power to the electromagnet 3, the detection sensor, the data processing module, and the data storage module.

[0028] In another technical solution, a plurality of electromagnets 3 are uniformly arranged on the side of the housing 1 facing the object being tested 5, and the magnetic field direction of each electromagnet 3 is the same. The unidirectional arrangement allows the magnetic fields of each electromagnet 3 to be superimposed in space, increasing the magnetic attraction force and avoiding the generation of local weak magnetic field areas.

[0029] In another technical solution, the detection sensor 4 is a strain gauge force sensor. The strain gauge force sensor utilizes the "deformation-resistance change" characteristic of the strain gauge to measure minute stretching or contraction in a structure and is insensitive to magnetic fields. The detection sensor 4 can be fixed by a bracket, allowing it to be tightly attached to the side of the electromagnet 3 facing the object being tested 5. The bracket is fixed to the housing 1. When the electromagnet attracts the object being tested 5, the reaction force of the object being tested 5 on the electromagnet 3 causes the strain gauge of the detection sensor 4, which is attached to it, to deform, thereby outputting a corresponding stress value signal.

[0030] In another technical solution, the component 5 to be inspected is a pipe, and the housing 1 is annular. The housing 1 is fitted onto the component 5 to detect defects on its outer peripheral surface. When the component 5 to be inspected is a pipe, the housing 1 is annular, and the housing 1 is fitted onto the component 5 to detect defects on its outer peripheral surface. Figure 3 As shown, the inner diameter of the housing 1 is larger than the outer diameter of the tested part 5, and the two are coaxially arranged; each of the electromagnets 3 is arranged on the inner side of the housing 1, and the walking device 2 drives the housing 1 to move longitudinally along the tested part 5 to detect the outer peripheral surface of the tested part 5.

[0031] In another technical solution, the component 5 to be tested is a pipe, and the housing 1 is annular. The housing 1 is disposed inside the component 5 to detect defects on the inner wall of the component 5. Figure 4 As shown, the outer diameter of the housing 1 is smaller than the inner diameter of the tested part 5, and the two are coaxially arranged; each of the electromagnets 3 is arranged on the outside of the housing 1, and the walking device 2 drives the housing 1 to move longitudinally along the tested part 5.

[0032] When the housing 1 is annular, if the electromagnet is provided with multiple rows of the detection sensors along the circumference of the detected component 5, such as Figure 2 and Figure 3 As shown, the sides of each electromagnet facing the object being tested 5 and the sides of the detection sensor 4 that are in contact with the electromagnet 3 are all curved surfaces to ensure that the distance between each detection sensor 4 and the object being tested 5 is consistent. If only one row of detection sensors is arranged along the circumference of the object being tested 5, the end face of the electromagnet 3 facing the object being tested 5 can be flat. By adjusting the angle and distance of each electromagnet 3 from the object being tested 5, it is ensured that the distance between each detection sensor 4 and the object being tested 5 is consistent. Figure 5 As shown.

[0033] In another technical solution, the component to be tested 5 is a plate-shaped structure, the length of the housing 1 is the same as the width of the component to be tested 5, and the walking device 2 drives the housing 1 to move along the longitudinal direction of the component to be tested to test the top surface of the component to be tested 5.

[0034] In another technical solution, the walking device 2 includes a drive motor and multiple wheels. Each wheel is rotatably connected to the housing 1 via a shaft. The drive motor is connected to the shafts of one or more wheels via a transmission device to drive the wheels to rotate. An encoder is installed on the shaft of one of the wheels. The encoder can measure the walking distance of the wheels, thereby locating the defect. The drive motor is fixed to the housing 1, and the transmission device is a conventional chain drive structure or belt drive structure. Preferably, one drive motor drives one or two wheels to rotate; multiple drive motors can also be provided to improve the walking efficiency of the housing 1. When the housing 1 is annular, the wheels can be positioned at the upper middle part of the corresponding pipe to drive the housing 1 to move, or as shown in the image. Figure 3 and Figure 4 As shown, each of the wheels is arranged in a circular array along the inner or outer side of the housing.

[0035] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for detecting defect depth based on magnetic force, characterized in that, include: By using a detection sensor fixed to an electromagnet, the magnitude of the magnetic attraction force of the electromagnet on the workpiece is detected as the electromagnet moves along the ferromagnetic workpiece. Based on the relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the workpiece, the defect depth value on the surface of the workpiece is calculated.

2. The defect depth detection method based on magnetic force as described in claim 1, characterized in that, The relationship between the magnetic attraction force and the distance between the electromagnet and the surface of the workpiece being tested is expressed by the following formula: In the above formula, F is the magnetic attraction force, µ0 is the vacuum permeability, K is the number of coil turns, I is the current, V is the volume of space occupied by the electromagnetic field, Φ is the magnetic flux, d1 is the distance between the electromagnet and the surface of the workpiece to be inspected, which is determined according to the inspection requirements; d2 is the defect depth.

3. The defect depth detection method based on magnetic force as described in claim 1, characterized in that, The electromagnet is fixed to the non-ferromagnetic housing on the side facing the object being tested, and the housing on the side facing the object being tested is also provided with a walking device to drive the housing to move along the object being tested; each electromagnet has multiple detection sensors arranged in a quincunx pattern on the side facing the object being tested.

4. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The housing contains a data processing module and a data storage module, and the detection sensor, the data processing module, and the data storage module are sequentially and communicatively connected.

5. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The housing is uniformly provided with a plurality of electromagnets on the side facing the object being tested, and the magnetic field direction of each electromagnet is the same.

6. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The detection sensor is a strain gauge force sensor.

7. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The component under test is a pipe, and the housing is annular. The housing is fitted onto the component under test to detect defects on the outer circumferential surface of the component under test.

8. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The component under test is a pipe, and the housing is annular. The housing is disposed inside the component under test and is used to detect defects on the inner wall of the component under test.

9. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The part to be tested has a plate-shaped structure, and the length of the housing is the same as the width of the part to be tested. The walking device drives the housing to move longitudinally along the part to be tested.

10. The defect depth detection method based on magnetic force as described in claim 3, characterized in that, The walking device includes a drive motor and multiple wheels. Each wheel is rotatably connected to the housing via a shaft. The drive motor is connected to the shaft of one or more wheels via a transmission device to drive the wheels to rotate. An encoder is provided on the shaft of one of the wheels.

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