A system and method for non-destructive testing of internal corrosion of a steel wire rope

Abstract

The present application relates to steel wire rope detection technical field, especially to a kind of for steel wire rope internal corrosion nondestructive testing system and method.The technical scheme includes neutron detection unit, electromagnetic detection unit, synchronous control unit, data processing and modeling computer, neutron detection unit is used to produce thermal neutron beam and irradiate steel wire rope, gamma energy spectrum generated after neutron and corrosion area interaction is collected, electromagnetic detection unit is used to magnetize steel wire rope and collect its magnetic flux leakage field signal, synchronous control unit, for recording the axial position of steel wire rope, data processing and modeling computer are connected with the neutron detection unit and electromagnetic detection unit signal, for receiving and processing neutron energy spectrum signal and electromagnetic signal.The present application provides a kind of steel wire rope internal corrosion nondestructive testing solution with high precision, strong reliability and comprehensive function by multi-technology fusion and innovative algorithm design, effectively improves the safety detection and evaluation ability of in-service steel wire rope.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel wire rope detection, and particularly relates to a system and method for nondestructive testing of internal corrosion of steel wire rope. BACKGROUND

[0002] As a key load-bearing component, steel wire rope is widely used in mechanical equipment in the fields of construction, mining, transportation, etc. Corrosion is one of the main forms leading to the failure of steel wire rope, which can significantly reduce the structural strength and fatigue life of steel wire rope, and constitutes a serious safety hazard. Therefore, it is crucial to effectively detect the internal corrosion of steel wire rope.

[0003] At present, the nondestructive testing methods applied to steel wire rope mainly include magnetic powder testing, ultrasonic testing and X-ray imaging, etc. However, these methods have obvious limitations in practical application: magnetic powder testing is only suitable for surface or near-surface defects; ultrasonic testing is prone to interference signals in complex steel wire rope structures, making it difficult to accurately identify internal corrosion; X-ray imaging has low sensitivity to light elements (such as hydrogen and oxygen), and hydrogen element is a key component of corrosion products (such as FeO(OH)), so it is difficult to effectively detect early corrosion.

[0004] Neutron detection technology is based on the interaction mechanism between neutrons and matter, and has high sensitivity to light elements. Neutron beams can penetrate high-density metal materials, and have non-elastic scattering or capture reactions with hydrogen, oxygen and other elements in the corrosion area, producing characteristic gamma rays or causing changes in thermal neutron flux. This characteristic enables neutron technology not only to realize three-dimensional positioning of corrosion areas, but also to distinguish the chemical form of corrosion products through energy spectrum analysis. However, single neutron energy spectrum analysis has limitations in spatial resolution.

[0005] Electromagnetic detection methods (such as magnetic flux leakage testing) can identify defects by detecting the change of the leakage magnetic field after magnetization of the steel wire rope, have high spatial resolution, and can effectively locate the approximate range of corrosion, but it is difficult to accurately quantify the degree of corrosion, especially to distinguish surface corrosion from internal corrosion.

[0006] In summary, there is a lack of a nondestructive testing method that can combine element composition analysis and geometric shape measurement, and realize qualitative identification and accurate quantification in the prior art. Therefore, the present application proposes a system and method for nondestructive testing of internal corrosion of steel wire rope. SUMMARY

[0007] The purpose of the present application is to solve the problem of low accuracy and reliability in detecting internal corrosion of steel wire rope in the background art, and to propose a system and method for nondestructive testing of internal corrosion of steel wire rope.

[0008] In a first aspect, the present application provides a system for nondestructive testing of internal corrosion of steel wire rope, comprising:

[0009] a neutron detection unit for generating a thermal neutron beam and irradiating the steel wire rope, and collecting a gamma energy spectrum generated after the neutrons interact with the rusted area;

[0010] an electromagnetic detection unit for magnetizing the steel wire rope and collecting a leakage magnetic field signal thereof;

[0011] a synchronous control unit for recording an axial position of the steel wire rope, the synchronous control unit being signal-connected with the neutron detection unit, the electromagnetic detection unit and a steel wire rope driving device;

[0012] a data processing and modeling computer signal-connected with the neutron detection unit and the electromagnetic detection unit, for receiving and processing the neutron spectrum signal and the electromagnetic signal, inverting a comprehensive rusted area quantitative index based on a joint calibration model, and reconstructing a three-dimensional model of the rusted area.

[0013] Optionally, the neutron detection unit comprises:

[0014] a compact D-D neutron source for generating a neutron beam;

[0015] a moderator tightly wrapped outside a target plate of the D-D neutron source for slowing down fast neutrons into thermal neutrons;

[0016] a LaBr3 gamma detector oppositely arranged with an exit port of the moderator for receiving and collecting characteristic gamma rays emitted from the rusted area of the steel wire rope;

[0017] a neutron shielding body surrounding the D-D neutron source, the moderator and the gamma detector.

[0018] Optionally, the electromagnetic detection unit comprises:

[0019] a through-type magnetizer with a central hole for the steel wire rope to pass through, for magnetizing the steel wire rope axially to saturation;

[0020] a Hall sensor array fixedly arranged in a surrounding manner at an exit side of the through-type magnetizer, for collecting a circumferential leakage magnetic signal of the steel wire rope surface;

[0021] a signal conditioning and acquisition module with an input end electrically connected with the Hall sensor array, for filtering, amplifying and analog-digital converting the leakage magnetic signal.

[0022] Optionally, the synchronous control unit comprises a high-precision encoder mechanically coupled with a driving roller or a guide wheel of the steel wire rope, for measuring an axial displacement of the steel wire rope in real time and synchronously sending a position signal to the signal conditioning and acquisition module and the data processing and modeling unit.

[0023] Optionally, the axial distance between the gamma detector in the neutron detection unit and the Hall sensor array in the electromagnetic detection unit is fixed.

[0024] In a second aspect, the present application provides a method for non-destructive testing of internal rust of a steel wire rope, applied to the non-destructive testing system for internal rust of a steel wire rope of the first aspect, the method comprising the following steps:

[0025] S1, starting the D-D neutron source in the neutron detection unit, adjusting the power and gas flow until the output of the thermal neutron beam is stable, and irradiating the steel wire rope running at a uniform speed;

[0026] S2, synchronously starting the electromagnetic detection unit and the synchronization control unit, magnetizing the steel wire rope with the through-type magnetizer, and collecting the magnetic leakage field signal B(z) through the Hall sensor array, while recording the axial position z of each frame signal through the encoder;

[0027] S3, collecting the gamma energy spectrum generated by the interaction of thermal neutrons and steel wire rope with the gamma detector, and obtaining the energy spectrum sequence S(z, E) along the axial position z;

[0028] S4, filtering and denoising the magnetic leakage field signal B(z) to obtain the processed signal den(B(z)), and calculating the electromagnetic rust index based on the metal cross-sectional area S and the outermost steel wire diameter R ;

[0029] S5, analyzing the energy spectrum sequence S(z, E), extracting the net count of hydrogen element characteristic peak and iron element characteristic peak and , and calculating the neutron rust index ;

[0030] S6, constructing a joint calibration model, data fusion of the electromagnetic rust index and the neutron rust index , and calculating the comprehensive rust quantification index ;

[0031] S7, based on the comprehensive rust quantification index , rust width and rust depth d, three-dimensional reconstruction and visualization of the internal rust area of the steel wire rope.

[0032] Optionally, the calculation formula of the electromagnetic rust index in step S4 is:

[0033]

[0034] wherein the rust cross-sectional area is estimated as , the rust width is .

[0035] Optionally, the neutron rust index in step S5 The calculation formula is:

[0036]

[0037] Wherein, k is the proportional constant determined by calibration experiment.

[0038] Optionally, the comprehensive rust quantification index in step S6 It is calculated by the following linear weighted fusion model:

[0039]

[0040] Wherein, the weight coefficient , , And constant term Determined by calibration fitting of known rust degree samples.

[0041] Compared with the prior art, the present application includes at least one of the following beneficial technical effects:

[0042] The high sensitivity of neutron spectrum analysis to hydrogen element is combined with the high spatial resolution of electromagnetic detection, overcoming the limitations of single detection method. Neutron technology can effectively perceive the light element composition in the corrosion product, while the electromagnetic method can accurately capture the geometric morphological characteristics of the defect, and the fusion of the two realizes cross-dimensional detection from component analysis to topographic measurement.

[0043] By establishing a joint calibration model, the data of neutron and electromagnetic signals are fused, the errors introduced by source intensity fluctuation, distance change and other system factors are eliminated, and the quantitative index that can comprehensively reflect the corrosion degree and range is output, which significantly improves the reliability of internal corrosion qualitative identification and accurate quantification.

[0044] The present application not only can give the quantitative index of corrosion, but also can inverse the width, depth and length information of corrosion according to the fused data, and further reconstruct the three-dimensional model of the corrosion area, realizing the intuitive and stereoscopic presentation of the defect, and providing a more comprehensive basis for safety evaluation and maintenance decision.

[0045] The system of the present application adopts a compact D-D neutron source, and is equipped with a boron-containing polyethylene neutron shielding body, which effectively ensures the radiation safety during operation while ensuring the neutron yield and detection efficiency. The fixed or parallel installation of the detection structure design and the synchronization control of the encoder ensure the synchronization and stability of the system detection under the dynamic running condition of the steel wire rope, and is suitable for nondestructive testing application in industrial field.

[0046] The application provides a high-precision, high-reliability and comprehensive-function steel wire rope internal corrosion nondestructive detection solution through multi-technology fusion and innovative algorithm design, and effectively improves the safety detection and evaluation capability of the in-service steel wire rope. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 Fig. 1 is a structural schematic diagram of a steel wire rope internal corrosion nondestructive detection system according to the application;

[0048] Figure 2 Fig. 2 is a flowchart of a steel wire rope internal corrosion nondestructive detection method according to the application. DETAILED DESCRIPTION

[0049] The embodiments of the application are described below with reference to specific examples. Those skilled in the art can easily understand other advantages and effects of the application from the content disclosed in the specification. The application can also be implemented or applied in other different embodiments, and the details in the specification can be modified or changed in various ways without departing from the spirit of the application. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0050] EMBODIMENT

[0051] Referring to Figure 1 The application provides a steel wire rope internal corrosion nondestructive detection system, which mainly includes two parts, a neutron detection part and an electromagnetic detection part. The neutron detection is based on a compact D-D neutron source and a LaBr3 gamma detector. The neutron source includes a radio frequency power supply and a radio frequency matcher, which are used to excite deuterium gas in a vacuum device to become plasma. An extraction electrode is used to accelerate and extract the generated plasma to obtain sufficient kinetic energy to strike a target plate to generate a large number of neutrons. The target plate here adopts a lithium target, and the moderator converts the generated fast neutrons into thermal neutrons to form a thermal neutron reference radiation beam. The thermal neutron beam strikes the running steel wire rope, the gamma detector collects the neutron energy spectrum of the corresponding position at each moment, and energy spectrum analysis is performed. At the same time, considering the safety of neutron radiation, the neutron shielding is protected by a boron-containing polyethylene plate.

[0052] An electromagnetic sensor is installed on each steel wire rope, signal processing is performed through a conditioning circuit, high-speed data acquisition is performed by using an electromagnetic acquisition module, the steel wire rope leakage magnetic field signal is obtained, and the approximate range of the steel wire rope corrosion is obtained. The neutron source and the detector are installed at a fixed distance from the electromagnetic probe, and can also be installed in parallel.

[0053] The encoder is used for recording the moving position of the steel wire rope, ensuring that the electromagnetic signal and the neutron spectrum signal are strictly synchronized and corresponding in space.

[0054] Need to be explained, the present application through the neutron detection unit relies on compact D-D neutron source and LaBr3 gamma detector, the sensitivity of hydrogen element (key component of corrosion product) in the corrosion area is extremely high, and the corrosion chemical form can be accurately identified;The electromagnetic detection unit can efficiently capture the change of the leakage magnetic field of the steel wire rope through the surrounding high-sensitivity Hall sensor array and the through-type magnetizer, and quickly lock the approximate range of corrosion. The two cooperate to avoid the problems of traditional single electromagnetic detection difficult to distinguish corrosion components and single neutron detection low spatial positioning accuracy, and realize the whole chain detection from range locking to component analysis.

[0055] Among them, the high-precision encoder is equipped with the steel wire rope running device linkage, which records the moving position of the steel wire rope in real time, ensures that the neutron spectrum signal and the leakage magnetic field signal are strictly corresponding in space, eliminates the detection error caused by signal misplacement, and provides accurate data basis for subsequent data fusion and index calculation. The neutron detection unit adopts a boron-containing polyethylene plate as a neutron shielding member, which can effectively block the leakage of neutron radiation and meet the safety operation requirements of industrial sites;At the same time, the neutron source and the electromagnetic sensor are installed in a fixed distance or parallel mode, which not only ensures the stability of signal acquisition, but also facilitates the overall layout and maintenance of the system.

[0056] In addition, the electromagnetic detection unit is designed to have one group of electromagnetic sensors corresponding to one steel wire rope for the detection requirement of multiple steel wire ropes, and the through-type magnetizer is used to realize the synchronous saturation magnetization of multiple steel wire ropes, which can adapt to different specifications and different numbers of steel wire rope detection scenes in the fields of building, mining and transportation, without the need to frequently adjust the equipment structure, thereby improving the detection efficiency.

[0057] Reference Figure 2 The present application provides a kind of for steel wire rope internal corrosion nondestructive testing method, first, compact D-D neutron source and steel wire rope are started before preparation work. Neutron source first starts vacuumizing, reaches 10 -7 Pa, starts to rush in argon at 20sccm. Open radio frequency power supply and radio frequency matching device, start neutron source, D+ deuterium plasma is gradually generated by bombarding lithium target. With the gradual increase of radio frequency power and deuterium, the neutron yield also gradually rises. When the neutron yield reaches 1E8n / s, and stabilizes for 5 minutes, open electromagnetic probe, start conditioning circuit and electromagnetic acquisition module. Through-type magnetizer is used to magnetize multiple steel wire ropes to saturation. Surrounding high-sensitivity Hall sensor array is used to collect circumferential leakage magnetic signals.

[0058] The steel wire rope running device and high-precision encoder are started, and the steel wire rope starts to run at a speed of 2 m / s. The electromagnetic probe starts to collect at a sampling rate of 10 kHz, collects the circumferential magnetic flux leakage signal at each position, and obtains the original one-dimensional magnetic flux leakage signal curve B(z), where z is the axial steel wire rope position. The original signal B(z) is filtered and denoised by using a low-pass filter and wavelet transform to obtain the processed signal den(B(z)). The signal amplitude at each axial position z is calculated and the average amplitude . Given the measured steel wire rope metal cross-sectional area S and the outermost steel wire diameter R, the average amplitude in a small lay distance Δz is reduced by n,

[0059]

[0060] Here, an electromagnetic corrosion index is defined , and the specific formula is

[0061]

[0062] where the corrosion cross-sectional area is estimated as , and the corrosion width is .

[0063] The gamma detector collects gamma energy spectrum at a low frequency sampling rate of 1 Hz, and each measurement point corresponds to an integration distance Δz, thereby obtaining an energy spectrum sequence S(z, E) along the axial position z, where E is the gamma ray energy. Considering that the number of hydrogen elements in the corrosion area is relatively obvious, the hydrogen characteristic peak of 2.223 MeV needs to be analyzed. The net count under the peak is calculated ,

[0064]

[0065] where E1 and E2 represent a small interval range containing the 2.223 MeV hydrogen characteristic peak, , and the background noise of the hydrogen element. At the same time, the net count of the iron peak is calculated ,

[0066]

[0067] where E3 and E4 represent a small interval range containing the 7.631 MeV iron characteristic peak, , and the background noise of the iron element.

[0068] Here, a neutron corrosion index is defined:

[0069]

[0070] where the proportionality constant , which needs to be determined by calibration experiments. This ratio eliminates the influence of system factors such as source intensity fluctuation and distance change, and directly reflects the relative concentration of hydrogen atoms and iron atoms, which is highly related to the corrosion degree. By pre-calibrating the corrosion cross-sectional proportion of the steel wire rope sample, the corrosion depth d of the steel wire rope can be obtained through the neutron corrosion index.

[0071] In order to better obtain the internal corrosion index of the steel wire rope, a joint calibration model is established here to fuse the electromagnetic signal and the neutron signal , and output a more accurate and reliable comprehensive corrosion quantitative index . According to the designed joint calibration algorithm, the two types of results are fused by linear weighting, that is

[0072]

[0073] Among them , , is the weight coefficient, is the constant term. The cross term is used to capture the correlation between the two signals. For the weight coefficient , , and the constant term , the coefficient is solved by the partially calibrated steel wire rope corrosion data, so that the true corrosion value is close. That is, the objective function T is minimized,

[0074]

[0075] Among them, represents the data points of all calibration steel wire rope samples.

[0076] According to the obtained steel wire rope corrosion width n and corrosion depth d, corrosion length z and comprehensive corrosion index , a modeling computer is used to model the corrosion area in three dimensions, and finally the results are presented through three-dimensional visualization technology.

[0077] In this embodiment, the method forms a standardized detection link through step-by-step operation (preparation before detection, neutron source start, electromagnetic module start, synchronous acquisition, signal processing, index calculation, three-dimensional reconstruction), and each step is set with clear technical parameters and operation standards: such as strictly control the vacuum degree (10-3Pa) when the neutron source starts. ), argon flow rate (20 sccm), neutron yield stable value (1E8 n / s), electromagnetic signal acquisition setting 10 kHz sampling rate, neutron energy spectrum acquisition setting 1 Hz sampling rate. The standardized process avoids human operation bias, ensures the consistency and comparability of data obtained by different detection scenarios and different operators, and improves the reliability of detection results.

[0078] The original magnetic leakage field signal is subjected to double noise reduction of low-pass filtering and wavelet transform, high-frequency interference and clutter are effectively removed, and the real corrosion signal is retained; the 2.223 MeV hydrogen characteristic peak and the 7.631 MeV iron characteristic peak are accurately extracted from the neutron energy spectrum sequence, the net count is calculated by background noise subtraction, and the interference of non-corrosion factors on the energy spectrum analysis is reduced.

[0079] It should be noted that the present application first calculates the electromagnetic corrosion index (reflecting the loss proportion of the cross-sectional area) and the neutron corrosion index (reflecting the hydrogen-iron element ratio, related to the corrosion degree) respectively, and then constructs a comprehensive corrosion quantitative index through a joint calibration model. The model introduces a cross term to capture the correlation between the two signals, combines the calibrated sample data to minimize the objective function, and finally obtains a comprehensive index that can reflect the influence of corrosion on the structure of the steel wire rope and the chemical properties of corrosion, accurately quantitatively evaluate the degree of corrosion, and solve the pain points of traditional methods that can only be qualitatively determined and cannot be quantitatively evaluated. The method finally constructs a three-dimensional model of the corrosion area based on the corrosion width (determined by the decrease in the amplitude of the electromagnetic signal), the corrosion depth (inverted by the neutron index), the corrosion length (determined by the position information of the encoder), and the comprehensive corrosion index, and visualizes the presentation. The detection personnel can intuitively obtain the position, shape and severity of the corrosion without the need for complex data deduction, which not only reduces the difficulty of result interpretation, but also provides accurate basis for steel wire rope maintenance (such as local repair and replacement decision), reduces safety risks and cost waste caused by excessive maintenance or insufficient maintenance.

[0080] The above specific embodiments are only several optional embodiments of the present application, and based on the technical solutions of the present application and the related inspiration of the above embodiments, those skilled in the art can make various alternative improvements and combinations on the above specific embodiments.

Claims

1. A non-destructive testing system for internal corrosion of a steel wire rope, characterized by, include: The neutron detection unit is used to generate a thermal neutron beam and irradiate the steel wire rope, and to collect the gamma spectrum generated after the interaction of neutrons with the rusted area. The electromagnetic detection unit is used to magnetize the wire rope and collect its leakage magnetic field signal. A synchronization control unit is used to record the axial position of the wire rope. The synchronization control unit is connected to the neutron detection unit, the electromagnetic detection unit, and the wire rope drive device. The data processing and modeling computer is signal-connected to the neutron detection unit and the electromagnetic detection unit. It is used to receive and process neutron energy spectrum signals and electromagnetic signals, invert the comprehensive corrosion quantification index based on the joint calibration model, and reconstruct a three-dimensional model of the corrosion area.

2. A system for non-destructive testing of internal corrosion of a steel wire rope according to claim 1, characterized in that, The neutron detection unit includes: A compact DD neutron source for generating neutron beams; The moderator is tightly wrapped around the outside of the target plate of the DD neutron source and is used to slow down fast neutrons into thermal neutrons; A LaBr3 gamma detector is positioned opposite the exit port of the moderator to receive and collect characteristic gamma rays emitted from the rusted area of ​​the wire rope. A neutron shield surrounds the DD neutron source, moderator, and gamma detector.

3. A system for non-destructive testing of internal corrosion of a steel wire rope according to claim 2, characterized in that The electromagnetic detection unit includes: A through-type magnetizer with a central channel through which a steel wire rope passes, used to axially magnetize the steel wire rope to saturation; A Hall sensor array is fixedly arranged in a circumferential manner on the outlet side of the through magnetizer to collect circumferential leakage magnetic signals on the surface of the wire rope. The signal conditioning and acquisition module, whose input terminal is electrically connected to the Hall sensor array, is used to filter, amplify, and convert the leakage magnetic signal into an analog-to-digital signal.

4. A system for non-destructive testing of internal corrosion of a steel wire rope according to claim 3, characterized in that The synchronization control unit includes a high-precision encoder, which is mechanically coupled to the drive roller or guide wheel of the wire rope. It is used to measure the axial displacement of the wire rope in real time and synchronously send the position signal to the signal conditioning and acquisition module and the data processing and modeling unit.

5. A system for non-destructive testing of internal corrosion of a steel wire rope as claimed in claim 4, wherein, The axial distance between the gamma detector in the neutron detection unit and the Hall sensor array in the electromagnetic detection unit is fixed.

6. A method for non-destructive testing of internal corrosion of a steel wire rope, applied to a system for non-destructive testing of internal corrosion of a steel wire rope according to any one of claims 4-5, characterized in that, The method includes the following steps: S1. Start the DD neutron source in the neutron detection unit, adjust its power and gas flow rate until a stable thermal neutron beam is output and irradiates the uniformly moving steel wire rope. S2. Simultaneously start the electromagnetic detection unit and the synchronous control unit, use the through magnetizer to magnetize the steel wire rope, and collect the leakage magnetic field signal B(z) through the Hall sensor array, while recording the axial position z of each frame signal through the encoder; S3. The gamma detector is used to collect the gamma energy spectrum generated by the interaction between thermal neutrons and steel wire rope, and the energy spectrum sequence S(z, E) distributed along the axial position z is obtained. S4, filtering and denoising the magnetic flux leakage field signal B(z) to obtain a processed signal den(B(z)), and calculating an electromagnetic corrosion index based on the metal cross-sectional area S and the outermost steel wire diameter R ; S5, analyzing the energy spectrum sequence S(z, E), extracting the net count of hydrogen element characteristic peak and iron element characteristic peak and , calculating the neutron corrosion index ; S6, construct a joint calibration model, the electromagnetic corrosion index and the neutron corrosion index Data fusion, calculate the comprehensive corrosion quantitative index ; S7、based on the comprehensive rust quantification index , rust width and rust depth d, the rust area inside the steel wire rope is three-dimensionally reconstructed and visualized.

7. A method for non-destructive testing of internal corrosion of a steel wire rope according to claim 6, characterized in that, The electromagnetic corrosion index in step S4 The calculation formula is: where the rusted cross-sectional area is estimated as and the rust width is .

8. A method for non-destructive testing of internal corrosion of a steel wire rope according to claim 6, characterized in that, The neutron corrosion index in step S5 The calculation formula is: where k is a proportionality constant determined by calibration experiments.

9. A method for non-destructive testing of internal corrosion of a steel wire rope according to claim 6, characterized in that, The comprehensive rust quantification index in step S6 By the following linear weighted fusion model: where the weight coefficient , , and constant term are determined by calibration fitting on samples with known rusting degree.

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