A high-temperature component dry magnetic powder magnetic flux leakage detection method based on a carrier tape

Abstract

The application discloses a kind of high-temperature component dry magnetic powder magnetic flux leakage detection methods based on carrier tape, belong to ferromagnetic material nondestructive testing field, comprising: one side of nonferromagnetic carrier tape is contacted with high-temperature component, high-temperature component is below Curie temperature ferromagnetic component;After magnetizing high-temperature component, dry magnetic powder is sprayed on the other side of nonferromagnetic carrier tape, and dry magnetic powder forms magnetic mark on the other side of nonferromagnetic carrier tape;Using laser displacement sensor, the other side of nonferromagnetic carrier tape is scanned uninterruptedly, and magnetic mark profile is obtained, and high-temperature component crack state is judged accordingly.The method of the application avoids the occurrence of the condition that the magnetic probe is damaged at high temperature under the small lifting value in the traditional magnetic flux leakage method, the magnetic permeability of nonferromagnetic carrier tape is close to air, and the magnetic flux leakage field is not greatly affected, the magnetic flux leakage field normally enters the air in the back of the carrier tape, dry magnetic powder is sprayed on the surface of the carrier tape, which is conducive to the movement of the magnetic powder, the formation of magnetic mark, and increases the accuracy and detection efficiency of high-temperature component detection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nondestructive testing of ferromagnetic materials, and more particularly relates to a dry magnetic powder magnetic flux leakage testing method for high-temperature components based on a carrier tape. BACKGROUND

[0002] At room temperature, the magnetic flux leakage testing technology for various ferromagnetic components has been widely applied, such as steel wire ropes, oil pipes, drill pipes, etc. In actual production, some ferromagnetic components after heat treatment change their ferromagnetic properties, and their nondestructive testing is more difficult. With the increase of temperature, the saturation magnetic induction intensity of the ferromagnetic components decreases, and the magnetic flux leakage signal weakens, and after reaching the Curie temperature, the ferromagnetic components lose their magnetism. In recent years, the demand for nondestructive testing of high-temperature components has expanded, but there are few studies on nondestructive testing of high-temperature components. The low lift-off value in ordinary magnetic flux leakage testing makes the probe too close to the component, and the probe is difficult to withstand the high temperature caused by the thermal radiation and conduction of the high-temperature component, so the problem of nondestructive testing of high-temperature components needs to be solved urgently.

[0003] The magnetic powder testing is similar to the magnetic flux leakage testing, and the magnetic powder is sprayed to the surface of the magnetized component, and the accumulation form of the magnetic powder can reflect the distribution of the magnetic flux leakage field of the ferromagnetic component. The traditional magnetic powder testing method mainly relies on manual observation of the magnetic marks, and the degree of automation is limited. By taking the magnetic powder as the observation object and arranging the probe far away from the surface of the component, the component can be tested remotely. In ordinary magnetic powder testing, the surface condition of the component greatly affects the movement of the magnetic powder and the formation of the magnetic mark. The surface of the measured component needs to be as smooth and clean as possible. The oil stains and rough surface of the component will form a magnetic flux leakage field that can attract the magnetic powder and interfere with the formation of the crack magnetic mark. For the measured component with poor surface condition, the movement of the magnetic powder is blocked, and the characteristics of the magnetic mark are not obvious.

[0004] Therefore, the existing nondestructive testing technology for ferromagnetic high-temperature components has the technical problems of difficulty for the detection probe to withstand the high temperature caused by the thermal radiation and conduction of the high-temperature component, difficulty for the magnetic mark characteristics of the measured component with poor surface condition to be obvious, and inaccuracy of the detection result. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a dry magnetic powder magnetic flux leakage testing method for high-temperature components based on a carrier tape, thereby solving the technical problems of difficulty for the detection probe to withstand the high temperature caused by the thermal radiation and conduction of the high-temperature component, difficulty for the magnetic mark characteristics of the measured component with poor surface condition to be obvious, and inaccuracy of the detection result in the existing nondestructive testing technology for ferromagnetic high-temperature components.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a dry magnetic powder magnetic flux leakage testing method for high-temperature components based on a carrier tape is provided, comprising:

[0007] One side of the non-ferromagnetic carrier tape is in contact with the high-temperature component, and the high-temperature component is a ferromagnetic component below the Curie temperature.

[0008] After magnetizing the high-temperature component, dry magnetic powder is sprayed on the other side of the non-ferromagnetic carrier belt, and the dry magnetic powder forms a magnetic mark on the other side of the non-ferromagnetic carrier belt;

[0009] The other side of the non-ferromagnetic carrier belt is continuously scanned using a laser displacement sensor to obtain a magnetic mark profile, and the crack state of the high-temperature component is determined according to the magnetic mark profile.

[0010] Further, the magnetic mark profile is obtained by the following method:

[0011] The other side of the non-ferromagnetic carrier belt is continuously scanned using a laser displacement sensor, and scanning data higher than a preset value of the other side of the non-ferromagnetic carrier belt is determined as crack magnetic mark profile data to form a magnetic mark profile, and the preset value is the height of 1-2 dry magnetic powders.

[0012] Further, the particle size of the dry magnetic powder is 60 microns-1000 microns.

[0013] Further, the method further comprises:

[0014] The magnetic mark profile is input into a deep learning regression model to obtain a crack profile of the high-temperature component;

[0015] The deep learning regression model is trained by the following method:

[0016] A high-temperature component with a known crack profile is used as a sample, one side of the non-ferromagnetic carrier belt is in contact with the sample, the high-temperature component is magnetized, dry magnetic powder is sprayed on the other side of the non-ferromagnetic carrier belt, a laser displacement sensor is used to continuously scan the other side of the non-ferromagnetic carrier belt, a sample magnetic mark profile is obtained, the sample magnetic mark profile is input into a deep learning regression model, and the error between the output crack profile and the known crack profile is used to update the parameters of the deep learning regression model in a reverse propagation manner until the model converges, thereby obtaining a trained deep learning regression model.

[0017] Further, the thickness of the non-ferromagnetic carrier belt is 10 microns-50 microns.

[0018] Further, the roughness of the other side of the non-ferromagnetic carrier belt is less than the surface roughness of the high-temperature component.

[0019] Further, the magnetization method is coil magnetization, magnetic yoke magnetization, or wire magnetization.

[0020] Further, after the scanning is completed, the magnetization power supply is turned off, alternating current demagnetization method is used to eliminate the residual magnetism of the high-temperature component, and the dry magnetic powder is recovered.

[0021] Further, when the dry magnetic powder is sprayed on the other side of the non-ferromagnetic carrier belt, the dry magnetic powder is uniformly sprayed multiple times, and the excess dry magnetic powder is removed.

[0022] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0023] (1) The high-temperature component is a ferromagnetic component below the Curie temperature. A ferromagnetic component with a temperature exceeding the Curie temperature will lose ferromagnetism and is not suitable for detection based on the magnetic flux leakage principle. The detection method provided by the present application infers the magnetic flux leakage field distribution and crack distribution by measuring the distribution pattern of the magnetic powder on the carrier tape. The laser displacement sensor can be measured remotely, avoiding the damage of the magnetic probe in the traditional magnetic flux leakage method under high temperature. The ferromagnetic carrier tape has a magnetic shielding effect, leaving most of the magnetic flux inside the carrier tape, and the magnetic flux leakage field in the air is small. The magnetic permeability of the non-ferromagnetic carrier tape is close to that of air, and has little effect on the magnetic flux leakage field, which normally enters the air behind the carrier tape. One side of the carrier tape is in close contact with the surface of the high-temperature component, and the other side serves as a medium for the movement of the magnetic powder. Relative to the complex surface of the component, it is conducive to the movement of the magnetic powder and the formation of the magnetic trace, increasing the detection rate, accuracy and detection efficiency of the high-temperature component.

[0024] (2) The deeper the crack, the stronger the magnetic flux leakage field, and the higher the magnetic powder pile. The crack profile is positively correlated with the magnetic trace profile. Based on this, the present application uses deep learning to train the model first, and then uses the trained model to predict the magnetic trace profile measured by the laser displacement sensor, to obtain the crack profile of the high-temperature component, which is conducive to the realization of high-speed automation. When processing the profile data obtained by the laser displacement sensor, a threshold algorithm is used, and data points higher than a certain value on the back of the carrier tape are determined as crack magnetic trace profile data. This can reduce irrelevant data and improve the training efficiency and the accuracy of model prediction.

[0025] (3) The thickness of the carrier tape is the lift-off value of the magnetic powder relative to the high-temperature component. Different thicknesses of the carrier tape result in changes in the lift-off value of the magnetic powder relative to the surface of the component. Due to the roughness of the component surface, a magnetic flux leakage field is generated. This magnetic flux leakage field is combined with the magnetic flux leakage field generated by the crack. As the lift-off layer becomes thicker, both the magnetic flux leakage field generated by the rough surface and the crack magnetic flux leakage field attenuate, but the attenuation amplitudes are different. Changing the thickness of the carrier tape can obtain the best signal-to-noise ratio. The thicker the thickness, the greater the signal magnetic field attenuation. After the signal-to-noise ratio meets the standard, the thickness is as small as possible. Based on this, the thickness of the non-ferromagnetic carrier tape is set by considering the signal-to-noise ratio and magnetic induction intensity. The surface of the high-temperature component is complex and not easy to clean. The roughness of the other side of the non-ferromagnetic carrier tape is smaller than that of the surface of the high-temperature component. Loading the magnetic powder onto it is conducive to the movement of the magnetic powder and has an enhancing effect on the magnetic trace characteristics, which can be manifested as a more complete magnetic trace morphology and a higher magnetic powder pile, which helps to improve the accuracy of detection.

[0026] (4) The magnetization mode of the present application is various to meet the detection requirements of high-temperature components of different shapes and different cracks. The double-coil arrangement magnetization can obtain a uniform magnetic field in the detected area, which is beneficial to the formation of magnetic marks. The magnetic yoke magnetization can apply magnetization to the high-temperature component in any direction, so as to detect cracks distributed in various directions and avoid missed detection.

[0027] (5) After magnetization, uniform magnetic powder is sprayed multiple times to the back of the carrier tape to remove excess dry magnetic powder, so as to ensure that the magnetic marks are clear and visible and the morphology is stable. After the scanning is completed, the magnetization power is turned off, and the alternating current demagnetization method is used to eliminate the residual magnetism of the high-temperature component. The magnetic field leakage at the crack of the component is removed, the magnetic powder is no longer adsorbed on the surface of the component, and the removal of the magnetic powder can be easily completed by means of vibration or wind power. The back of the carrier tape is smooth and clean, and the removed magnetic powder can be recycled multiple times. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a principle diagram of a high-temperature component dry magnetic powder magnetic leakage detection method based on a carrier tape provided by an embodiment of the present application;

[0029] Figure 2 is an axial coil magnetization diagram involved in the high-temperature component dry magnetic powder magnetic leakage detection method based on a carrier tape provided by an embodiment of the present application;

[0030] Figure 3 is a magnetic yoke magnetization diagram involved in the high-temperature component dry magnetic powder magnetic leakage detection method based on a carrier tape provided by an embodiment of the present application;

[0031] Figure 4 is a local magnification principle diagram of a ferromagnetic carrier tape defect provided by an embodiment of the present application;

[0032] Figure 5 is a local magnification principle diagram of a non-ferromagnetic carrier tape defect provided by an embodiment of the present application;

[0033] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0034] 1 is a high-temperature component, 2 is a magnetic induction line, 3 is a crack, 4 is a carrier tape, 5 is a magnetic powder pile, 6 is a magnetization coil, 7 is a magnetic powder spray gun, 8 is a laser displacement sensor, 9 is a fan, 10 is a magnetic yoke magnetizer, 11 is a ferromagnetic carrier tape, and 12 is a non-ferromagnetic carrier tape. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] The present application provides a kind of high temperature component dry magnetic powder magnetic flux leakage detection method based on carrier tape, comprising the following steps:

[0037] Step one: install detection system, arrange carrier tape on the surface of high temperature component.

[0038] Specifically, the high temperature component is a ferromagnetic component below Curie temperature. It should be noted that the ferromagnetic component with temperature exceeding Curie temperature will lose ferromagnetism, and is not suitable for detection based on magnetic flux leakage principle. The carrier tape is a thin tape with a thickness of 10 microns to 50 microns, and the carrier tape needs to be closely attached to the surface of the high temperature component. The thickness of the carrier tape is the lift-off value of the magnetic powder relative to the high temperature component. The carrier tape needs to be made of high-temperature-resistant material. The carrier tape is a non-ferromagnetic material, and the selection of the material and the thickness of the carrier tape will affect the distribution of the magnetic flux leakage field and the formation of the magnetic mark. The back of the carrier tape is a smooth surface, and the magnetic mark is formed quickly and has strong characteristics.

[0039] Step two: magnetize the high temperature component, and spray dry magnetic powder on the back of the carrier tape;

[0040] Specifically, a variety of magnetizing devices can be selected to meet the detection needs of high temperature components of different shapes and different cracks, including coil magnetization, magnetic yoke magnetization, wire magnetization, etc. The magnetic powder spray gun and the fan are used for uniform spraying of magnetic powder and blowing of excess magnetic powder, respectively. The surface of the high temperature component is complex and not easy to clean, while the back of the carrier tape is a clean smooth surface, which is beneficial to the movement of the magnetic powder and enhances the characteristics of the magnetic mark. It can be manifested as more complete magnetic mark morphology and higher magnetic powder pile height.

[0041] Step three: use a laser displacement sensor to scan the back of the carrier tape continuously to obtain the distribution pattern of the dry magnetic powder, and judge the crack state of the high temperature component according to the distribution pattern.

[0042] Specifically, the laser displacement sensor can measure two-dimensional data on a line. When the probe head forms relative motion with the carrier tape, continuous measurement can obtain the three-dimensional profile of the back of the carrier tape and the magnetic mark. Then, according to the defect reconstruction algorithm, the distribution of the crack is judged, and a qualitative and quantitative analysis of the crack is given. When the magnetic powder pile reaches a certain height, it indicates that the crack exists. According to the width, cross-sectional area and other information of the magnetic powder pile, more specific crack information can be given, including crack width, depth, etc. The target area of single detection is the component surface area covered by the carrier tape.

[0043] Wherein, when processing the profile data obtained by the laser displacement sensor, the surface of the carrier tape is first calibrated by a clustering algorithm. A threshold algorithm is used, and data points higher than a certain value of the back surface of the carrier tape are determined as crack magnetic mark profile data. The threshold value can be set to 60-1000 microns according to the particle size of the dry magnetic powder used, which is about the height of two magnetic powder particles, so as to obtain the three-dimensional profile data of the magnetic mark. The three-dimensional structure of the crack is inferred from the three-dimensional profile data of the magnetic mark. A deep learning model is designed, which can assume that the cross section of the crack is rectangular, and a deep learning regression model from the magnetic mark cross section data to the crack length and width is established. After network training, the three-dimensional profile of the crack can be calculated from the magnetic mark profile.

[0044] As shown in Figure 1 The high-temperature component 1 is a ferromagnetic component with a temperature below the Curie temperature, and has a certain ferromagnetic property. When it is magnetized, the magnetic induction line 2 passes through the component, and at the crack 3, the magnetic induction line 2 changes, and a part of the magnetic induction line is transmitted out of the upper surface of the component, forming a leakage magnetic field above the component. When the carrier tape is a non-ferromagnetic material, the carrier tape 4 has little effect on the distribution of the leakage magnetic field. When the carrier tape 4 is a ferromagnetic material, it will change the distribution of the leakage magnetic field. Spraying magnetic powder under different leakage magnetic fields and blowing away excess magnetic powder will form different forms of magnetic powder pile 5. The form of the magnetic powder pile 5 can be obtained by measuring with a laser displacement sensor, and the characteristics of the crack 3, including the existence and size of the crack 3, can be judged accordingly.

[0045] As shown in Figure 2 A magnetizing coil 6 is used to apply a magnetic field to the high-temperature component 1 for magnetization. The arrangement of double coils can obtain a more uniform magnetic field in the measured area, which is beneficial to the formation of magnetic marks. After magnetization, the magnetic powder spray gun 7 sprays uniform magnetic powder to the back surface of the carrier tape 4, and the fan 9 blows away the excess magnetic powder on the back surface of the carrier tape 4. The spraying is repeated three to four times to ensure that the magnetic mark is clear and stable in form. After scanning by the laser displacement sensor 8, the data is transmitted to the upper computer for further processing. After scanning is completed, the magnetization power supply is turned off, and the alternating current demagnetization method is used to eliminate the residual magnetism of the high-temperature component, the leakage magnetic field at the crack of the component is removed, and the magnetic powder is no longer adsorbed on the surface of the component. The removal of the magnetic powder can be easily completed by vibration or air flow. The back surface of the carrier tape is smooth and clean, and the removed magnetic powder can be recycled multiple times.

[0046] As shown in Figure 3 A magnetizing coil 6 is used to apply a magnetic field to the high-temperature component 1 for magnetization. The arrangement of double coils can obtain a more uniform magnetic field in the measured area, which is beneficial to the formation of magnetic marks. After magnetization, the magnetic powder spray gun 7 sprays uniform magnetic powder to the back surface of the carrier tape 4, and the fan 9 blows away the excess magnetic powder on the back surface of the carrier tape 4. The spraying is repeated three to four times to ensure that the magnetic mark is clear and stable in form. After scanning by the laser displacement sensor 8, the data is transmitted to the upper computer for further processing. After scanning is completed, the magnetization power supply is turned off, and the alternating current demagnetization method is used to eliminate the residual magnetism of the high-temperature component, the leakage magnetic field at the crack of the component is removed, and the magnetic powder is no longer adsorbed on the surface of the component. The removal of the magnetic powder can be easily completed by vibration or air flow. The back surface of the carrier tape is smooth and clean, and the removed magnetic powder can be recycled multiple times.

[0047] AsFigure 4 As shown, in order to improve the morphology of the magnetic mark, the method of the present application introduces a carrier tape. The ferromagnetic carrier tape 11 has a magnetic shielding effect, leaving most of the magnetic flux inside the carrier tape, and the leakage magnetic field in the air is small. As shown Figure 5 As shown, the magnetic permeability of the non-ferromagnetic carrier tape 12 is close to air, and has little effect on the leakage magnetic field, and the leakage magnetic field normally enters the air behind the carrier tape. However, the thicker the carrier tape, the smaller the surface leakage magnetic field. Therefore, the carrier tape in the present application should be as thin as possible on the basis of meeting the magnetic mark enhancement effect. Therefore, the carrier tape in the present application is a non-ferromagnetic thin tape.

[0048] The high-temperature component dry magnetic powder leakage magnetic detection method based on a carrier tape provided by the present application can also be used for leakage magnetic detection of normal-temperature ferromagnetic components, and can also be used for ferromagnetic components greater than normal temperature and less than Curie temperature.

[0049] The high-temperature component crack detection method provided by the method of the present application can be magnetized by a coil or a magnetic yoke type magnetizer, and the carrier tape back surface can be used to receive the magnetic powder, and a laser displacement sensor can be used for scanning to obtain the magnetic powder distribution morphology data, and a defect reconstruction algorithm can be used to judge the crack state. The method increases the lift-off value of the leakage magnetic detection, and meets the detection requirements of the high-temperature component. The material and thickness of the carrier tape are designed, and the smooth surface is processed to improve the distribution characteristics of the magnetic powder pile.

[0050] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier tape, characterized in that, include: One side of the non-ferromagnetic carrier tape is in contact with a high-temperature component, which is a ferromagnetic component with a temperature below the Curie temperature. After magnetizing the high-temperature component, dry magnetic powder is sprayed on the other side of the non-ferromagnetic carrier tape, and the dry magnetic powder forms a magnetic mark on the other side of the non-ferromagnetic carrier tape. A laser displacement sensor is used to continuously scan the other side of the non-ferromagnetic carrier to obtain the magnetic trace profile, which is then used to determine the crack state of the high-temperature component. The surface roughness of the other side of the non-ferromagnetic carrier tape is less than that of the surface roughness of the high-temperature component.

2. The method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt as described in claim 1, characterized in that, The magnetic trace contour is obtained in the following manner: A laser displacement sensor is used to continuously scan the other side of the non-ferromagnetic carrier. The scanning data that is higher than a preset value on the other side of the non-ferromagnetic carrier is determined as the magnetic trace profile data of the crack, forming the magnetic trace profile. The preset value is the height of 1-2 dry magnetic powder particles.

3. The method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt as described in claim 2, characterized in that, The particle size of the dry magnetic powder is 60 micrometers to 1000 micrometers.

4. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt, as described in claim 2 or 3, characterized in that, The method further includes: The magnetic trace profile is input into a deep learning regression model to obtain the crack profile of the high-temperature component. The deep learning regression model is trained in the following manner: Using a high-temperature component with a known crack profile as a sample, one side of a non-ferromagnetic carrier strip is brought into contact with the sample. After magnetizing the high-temperature component, dry magnetic powder is sprayed onto the other side of the non-ferromagnetic carrier strip. A laser displacement sensor is used to continuously scan the other side of the non-ferromagnetic carrier strip to obtain the magnetic trace profile of the sample. The magnetic trace profile of the sample is input into a deep learning regression model. The error between the output crack profile and the known crack profile is backpropagated to update the parameters of the deep learning regression model. The model is trained until convergence to obtain a well-trained deep learning regression model.

5. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt, as described in claim 1 or 2, characterized in that, The thickness of the non-ferromagnetic carrier tape is 10 micrometers to 50 micrometers.

6. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt, as described in claim 1 or 2, characterized in that, The magnetization method is coil magnetization, yoke magnetization, or wire magnetization.

7. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt, as described in claim 1 or 2, characterized in that, After the scan is completed, the magnetization power supply is turned off, and the residual magnetism of the high-temperature components is eliminated by AC demagnetization method, and the dry magnetic powder is recovered.

8. A method for detecting magnetic flux leakage of high-temperature components using dry magnetic powder based on a carrier belt, as described in claim 1 or 2, characterized in that, When spraying dry magnetic powder on the other side of the non-ferromagnetic carrier tape, spray evenly multiple times and then blow away the excess dry magnetic powder.

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