Nondestructive testing system and method for corrosion inside steel wire rope

Abstract

The invention relates to the technical field of steel wire rope detection, in particular to a nondestructive testing system and method for corrosion inside a steel wire rope. According to the technical scheme, the device comprises a neutron detection unit, an electromagnetic detection unit, a synchronous control unit and a data processing and modeling computer, and the neutron detection unit is used for generating thermal neutron beams, irradiating a steel wire rope and collecting gamma-ray energy spectrums generated after interaction of neutrons and a corrosion area; the neutron detection unit is used for detecting neutron energy spectrum signals and electromagnetic signals, the electromagnetic detection unit is used for magnetizing the steel wire rope and collecting leakage magnetic field signals of the steel wire rope, the synchronous control unit is used for recording the axial position of the steel wire rope, and the data processing and modeling computer is in signal connection with the neutron detection unit and the electromagnetic detection unit and used for receiving and processing neutron energy spectrum signals and electromagnetic signals. Through multi-technology fusion and innovative algorithm design, the invention provides a nondestructive testing solution for internal corrosion of the steel wire rope with high precision, strong reliability and comprehensive functions, and the safety detection and evaluation capability of the in-service steel wire rope is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of wire rope testing technology, and in particular to a non-destructive testing system and method for internal corrosion testing of wire ropes. Background Technology

[0002] Wire ropes, as critical load-bearing components, are widely used in machinery and equipment in construction, mining, transportation, and other fields. Corrosion is one of the main causes of wire rope failure, significantly reducing its structural strength and fatigue life, posing a serious safety hazard. Therefore, effective detection of internal corrosion in wire ropes is crucial.

[0003] Currently, non-destructive testing methods applied to wire ropes mainly include magnetic particle testing, ultrasonic testing, and X-ray imaging. However, these methods have significant limitations in practical applications: magnetic particle testing is only applicable to surface or near-surface defects; ultrasonic testing is prone to generating interference signals in complex wire rope structures, making it difficult to accurately identify internal corrosion; and X-ray imaging has low sensitivity to light elements (such as hydrogen and oxygen), while hydrogen is a key component of corrosion products (such as FeO(OH)), thus making it difficult to effectively detect early corrosion.

[0004] Neutron detection technology, based on the interaction mechanism between neutrons and matter, exhibits high sensitivity to light elements. Neutron beams can penetrate high-density metallic materials, undergoing inelastic scattering or capture reactions with elements such as hydrogen and oxygen in the corroded region, producing characteristic gamma rays or causing changes in thermal neutron flux. This characteristic allows neutron technology to not only achieve three-dimensional localization of corroded regions but also to identify the chemical forms of corrosion products through energy spectrum analysis. However, single neutron energy spectrum analysis has limitations in terms of spatial resolution.

[0005] Electromagnetic detection methods (such as magnetic flux leakage detection) identify defects by detecting changes in the magnetic flux leakage field after the wire rope is magnetized. They have high spatial resolution and can effectively locate the approximate extent of corrosion, but they are difficult to accurately quantify the degree of corrosion, and in particular, they cannot distinguish between surface corrosion and internal corrosion.

[0006] In summary, existing technologies lack a non-destructive testing method that can simultaneously perform elemental composition analysis and geometric morphology measurement, achieving a combination of qualitative identification and precise quantitative analysis. Therefore, this application proposes a non-destructive testing system and method for internal corrosion detection of steel wire ropes. Summary of the Invention

[0007] The purpose of this invention is to address the problem of low accuracy and reliability in detecting internal corrosion of steel wire ropes in the prior art, and to propose a non-destructive testing system and method for internal corrosion of steel wire ropes.

[0008] In a first aspect, the present invention provides a non-destructive testing system for internal corrosion of steel wire ropes, comprising:

[0009] 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.

[0010] The electromagnetic detection unit is used to magnetize the wire rope and collect its leakage magnetic field signal.

[0011] 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.

[0012] 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.

[0013] Optionally, the neutron detection unit includes:

[0014] A compact DD neutron source for generating neutron beams;

[0015] 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.

[0016] 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.

[0017] A neutron shield surrounds the DD neutron source, moderator, and gamma detector.

[0018] Optionally, the electromagnetic detection unit includes:

[0019] A through-type magnetizer, with a central channel through which a steel wire rope passes, is used to axially magnetize the steel wire rope to saturation;

[0020] 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.

[0021] 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.

[0022] Optionally, the synchronization control unit includes a high-precision encoder, which is mechanically coupled to the drive roller or guide wheel of the wire rope 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.

[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] Secondly, the present invention provides a method for non-destructive testing of internal corrosion in steel wire ropes, applied to the non-destructive testing system for internal corrosion in steel wire ropes described in the first aspect. The method includes the following steps:

[0025] 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.

[0026] 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;

[0027] S3. Using the gamma detector, collect the gamma energy spectrum generated by the interaction between thermal neutrons and the steel wire rope to obtain the energy spectrum sequence S(z, E) distributed along the axial position z.

[0028] S4. The leakage magnetic field signal B(z) is filtered and denoised to obtain the processed signal den(B(z)). Based on the metal cross-sectional area S and the outermost steel wire diameter R, the electromagnetic corrosion index is calculated. ;

[0029] S5. Analyze the energy spectrum sequence S(z, E) and extract the net count of the characteristic peaks of hydrogen and iron. and Calculate the neutron corrosion index ;

[0030] S6. Construct a joint calibration model to integrate the electromagnetic corrosion indexes. and the neutron corrosion index Data fusion was performed to calculate a comprehensive quantitative index of corrosion. ;

[0031] S7. Based on the aforementioned comprehensive corrosion quantification index , Corrosion width Based on the corrosion depth d, the rusted area inside the wire rope is reconstructed and visualized in three dimensions.

[0032] Optionally, the electromagnetic corrosion index mentioned in step S4 The calculation formula is:

[0033]

[0034] The estimated cross-sectional area of ​​corrosion is as follows: The width of the rust is .

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

[0036]

[0037] Where k is a proportionality constant determined through calibration experiments.

[0038] Optionally, the comprehensive corrosion quantification index mentioned in step S6 Calculated using the following linear weighted fusion model:

[0039]

[0040] Among them, the weighting coefficient , , and constant term The determination was made by calibration and fitting of samples with known corrosion levels.

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

[0042] Combining the high sensitivity of neutron energy spectroscopy for hydrogen with the high spatial resolution of electromagnetic detection overcomes the limitations of single detection methods. Neutron technology can effectively detect the light element composition in corrosion products, while electromagnetic methods can accurately capture the geometric morphological features of defects. The fusion of the two enables cross-dimensional detection from compositional analysis to morphological measurement.

[0043] By establishing a joint calibration model and fusing neutron and electromagnetic signals, errors introduced by system factors such as source strength fluctuations and distance changes are eliminated. The output is a quantitative index that can comprehensively reflect the degree and extent of corrosion, which significantly improves the reliability of qualitative identification and accurate quantification of internal corrosion.

[0044] This invention not only provides quantitative indicators of corrosion, but also infers the width, depth and length of corrosion based on the fused data, thereby reconstructing a three-dimensional model of the corrosion area. This enables an intuitive and three-dimensional presentation of the defects, providing a more comprehensive basis for safety assessment and maintenance decisions.

[0045] The system of this invention employs a compact DD neutron source and is equipped with a boron-containing polyethylene neutron shield, effectively ensuring radiation safety during operation while guaranteeing neutron yield and detection efficiency. The fixed or parallel installation design of the detection structure and the synchronous control of the encoder ensure the synchronicity and stability of the system under dynamic wire rope operation conditions, making it suitable for non-destructive testing applications in industrial settings.

[0046] This invention provides a high-precision, highly reliable, and comprehensive non-destructive testing solution for internal corrosion of steel wire ropes through the integration of multiple technologies and innovative algorithm design, effectively improving the safety inspection and evaluation capabilities of in-service steel wire ropes. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a non-destructive testing system for internal corrosion of steel wire ropes.

[0048] Figure 2 This is a flowchart of a method for non-destructive testing of internal corrosion in steel wire ropes. Detailed Implementation

[0049] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0050] Example

[0051] See Figure 1 This invention proposes a non-destructive testing system for internal corrosion of steel wire ropes. The system mainly consists of two parts: neutron detection and electromagnetic detection. The neutron detection is based on a compact DD neutron source and a LaBr3 gamma detector. The neutron source includes a radio frequency power supply and a radio frequency matching unit to excite deuterium gas in a vacuum device, turning it into plasma. Extraction electrodes are used to accelerate and extract the generated plasma, acquiring sufficient kinetic energy to strike a target plate, generating a large number of neutrons. The target plate is a lithium target, and a moderator converts the generated fast neutrons into thermal neutrons, forming a thermal neutron reference radiation beam. The thermal neutron beam strikes the operating steel wire rope, and the gamma detector collects the neutron energy spectrum at each corresponding position at each moment for energy spectrum analysis. Simultaneously, considering neutron radiation safety, neutron shielding is performed using boron-containing polyethylene plates.

[0052] Each steel wire rope is equipped with an electromagnetic sensor. Signal processing is performed via a conditioning circuit, and high-speed data acquisition is conducted using an electromagnetic acquisition module to obtain the leakage magnetic field signal of the steel wire rope, thus determining the approximate extent of corrosion. The neutron source and detector are installed at a fixed distance from the electromagnetic probe, or they can be installed parallel to each other.

[0053] The encoder records the movement of the wire rope, ensuring that the electromagnetic signal and the neutron energy spectrum signal are strictly synchronized in space. The modeling computer uses the electromagnetic and neutron energy spectrum signals to obtain a comprehensive quantitative index of corrosion and performs three-dimensional reconstruction of the corroded area.

[0054] It should be noted that this invention utilizes a neutron detection unit, relying on a compact DD neutron source and a LaBr3 gamma detector, to achieve extremely high sensitivity to hydrogen (a key component of corrosion products) in the rust region, enabling precise identification of the chemical morphology of the rust. The electromagnetic detection unit, through a surrounding high-sensitivity Hall sensor array and a through-type magnetizer, efficiently captures changes in the leakage magnetic field of the steel wire rope, quickly pinpointing the approximate area of ​​the rust. The synergy of these two components avoids the problems of traditional single electromagnetic detection's difficulty in identifying rust components and single neutron detection's low spatial positioning accuracy, achieving a full-chain detection from area localization to component analysis.

[0055] The system is equipped with a high-precision encoder linked to a wire rope running device, which records the wire rope's movement in real time. This ensures a strict one-to-one spatial correspondence between the neutron energy spectrum signal and the leakage magnetic field signal, eliminating detection errors caused by signal misalignment and providing a precise data foundation for subsequent data fusion and index calculation. The neutron detection unit uses boron-containing polyethylene plates as neutron shielding, effectively blocking neutron radiation leakage and meeting the safety requirements for industrial operations. Simultaneously, the neutron source and electromagnetic sensors are installed at a fixed distance or in parallel, ensuring signal acquisition stability while facilitating overall system layout and maintenance.

[0056] In addition, the electromagnetic detection unit is designed to meet the detection needs of multiple wire ropes by using a layout where one set of electromagnetic sensors corresponds to one wire rope. It also achieves synchronous saturation magnetization of multiple wire ropes through a through-type magnetizer. This design is suitable for detection scenarios of different specifications and quantities of wire ropes in fields such as construction, mining, and transportation. It eliminates the need for frequent adjustments to the equipment structure and improves detection efficiency.

[0057] See Figure 2 This invention proposes a non-destructive testing method for internal corrosion of steel wire ropes. First, pre-start preparations are performed on the compact DD neutron source and the steel wire rope. The neutron source is first evacuated to a vacuum level of 10... -7 After Pa, argon gas was introduced at a rate of 20 sccm. The RF power supply and RF matching unit were turned on, and the neutron source was activated. D+ deuterium plasma gradually generated neutrons by bombarding the lithium target. As the RF power and deuterium gas gradually increased, the neutron yield also gradually increased. When the neutron yield reached 1E8n / s and stabilized for 5 minutes, the electromagnetic probe was turned on, and the conditioning circuit and electromagnetic acquisition module were activated. A through-type magnetizer was used to magnetize multiple steel wire ropes to saturation. A high-sensitivity Hall sensor array was arranged in a ring to collect the circumferential leakage magnetic signal.

[0058] The wire rope running device and high-precision encoder are started, and the wire rope begins to move at 2 m / s. The electromagnetic probe begins acquiring circumferential magnetic flux leakage signals at a sampling rate of 10 kHz, obtaining the original one-dimensional magnetic flux leakage signal curve B(z), where z represents the axial position of the wire rope. A low-pass filter and wavelet transform are used to filter and reduce noise in the original signal B(z), resulting in the processed signal den(B(z)). The signal amplitude at each axial position z is calculated. and average amplitude Given the measured cross-sectional area S of the steel wire rope and the diameter R of the outermost wire, the average amplitude within a small lay length Δz decreased by n.

[0059]

[0060] Here we define an electromagnetic corrosion index. The specific formula is as follows

[0061]

[0062] The estimated cross-sectional area of ​​corrosion is as follows: The width of the rust is .

[0063] A gamma detector acquires gamma energy spectra at a low sampling rate of 1 Hz. Each measurement point corresponds to an integration distance Δz, resulting in an energy spectrum sequence S(z,E) distributed along the axial position z, where E is the gamma ray energy. Considering the significant hydrogen content in the corroded region, the hydrogen characteristic peak at 2.223 MeV is the focus of analysis. The net count at this peak is calculated. ,

[0064]

[0065] Where E1 and E2 represent the small interval range including the 2.223 MeV hydrogen characteristic peak, This represents the background noise from hydrogen. Simultaneously, the net count of the iron peak needs to be calculated. ,

[0066]

[0067] E3 and E4 represent the small interval range including the 7.631 MeV iron characteristic peak. This is background noise for iron.

[0068] Here we define a neutron corrosion index:

[0069]

[0070] Among them, the proportionality constant This needs to be determined through calibration experiments. This ratio eliminates the influence of systemic factors such as source strength fluctuations and distance variations, directly reflecting the relative concentrations of hydrogen and iron atoms, and is highly correlated with the degree of corrosion. By pre-calibrating the corrosion cross-sectional ratio of the wire rope sample, the corrosion depth d of the wire rope can be obtained through the neutron corrosion index.

[0071] To better obtain the internal corrosion index of the wire rope, a joint calibration model is established here to integrate electromagnetic signals. and neutron signal By integrating these indicators, a more accurate and reliable comprehensive quantification of corrosion can be generated. Based on the designed joint calibration algorithm, the two types of results are fused through linear weighting, i.e.

[0072]

[0073] in , , These are weighting coefficients. It is a constant term. Intersection term. Used to capture the correlation between two signals. For the weighting coefficients... , , and constant term The value of is obtained by solving for coefficients using partially calibrated wire rope corrosion data, thus approximating the actual corrosion value. Even if the objective function T is minimized,

[0074]

[0075] in, This represents the data points for all calibrated wire rope samples.

[0076] Based on the obtained corrosion width n, corrosion depth d, corrosion length z, and comprehensive corrosion index of the wire rope The corrosion area is modeled in three dimensions using a computer modeling system, and the results are presented using three-dimensional visualization technology.

[0077] In this embodiment, the method forms a standardized detection chain through step-by-step operations (pre-detection preparation, neutron source startup, electromagnetic module startup, synchronous acquisition, signal processing, index calculation, and 3D reconstruction). Each step has clearly defined technical parameters and operating standards: for example, strictly controlling the vacuum level during neutron source startup (…). The parameters included argon flow rate (20 sccm), stable neutron yield (1E8n / s), electromagnetic signal acquisition with a sampling rate of 10 kHz, and neutron energy spectrum acquisition with a sampling rate of 1 Hz. This standardized process avoided human error, ensuring consistency and comparability of data obtained from different detection scenarios and by different operators, thus improving the reliability of the detection results.

[0078] For the original leakage magnetic field signal, low-pass filtering and wavelet transform are used for dual noise reduction to effectively remove high-frequency interference and clutter, and retain the true corrosion signal. 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 subtracting background noise to reduce the interference of non-corrosion factors on the energy spectrum analysis.

[0079] It should be noted that this invention first calculates the electromagnetic corrosion index (reflecting the proportion of cross-sectional area loss) and the neutron corrosion index (reflecting the proportion of hydrogen and iron elements, which is related to the degree of corrosion) separately, and then constructs a comprehensive corrosion quantification index through a joint calibration model. This model introduces cross terms to capture the correlation between the two signals, and combines the calibrated sample data to minimize the objective function to solve the weights. The final comprehensive index can reflect both the impact of corrosion on the wire rope structure and the chemical characteristics of corrosion, achieving a precise quantitative evaluation of the degree of corrosion and solving the pain point of traditional methods that can only make qualitative judgments and cannot make quantitative assessments. The method finally uses a three-dimensional modeling algorithm to construct a three-dimensional model of the corrosion area based on the corrosion width (determined by the reduction in electromagnetic signal amplitude), corrosion depth (inverted from the neutron index), corrosion length (determined by encoder position information), and the comprehensive corrosion index, and presents it visually. Inspectors can intuitively obtain the location, morphology, and severity of corrosion without the need for inference through complex data. This reduces the difficulty of interpreting the results and provides a precise basis for wire rope maintenance (such as local repair and replacement decisions), reducing the safety risks and cost waste caused by over-maintenance or under-maintenance.

[0080] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A non-destructive testing system for internal rust detection of steel wire ropes, characterized in that, 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. The non-destructive testing system for internal corrosion of steel wire ropes 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. The non-destructive testing system for internal corrosion of steel wire ropes according to claim 1, characterized in that, The electromagnetic detection unit includes: A through-type magnetizer, with a central channel through which a steel wire rope passes, is 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. The non-destructive testing system for internal corrosion of steel wire ropes according to claim 1, 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 non-destructive testing system for internal corrosion of steel wire ropes according to claim 1, characterized in that, 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 in steel wire ropes, applied to the non-destructive testing system for internal corrosion in steel wire ropes as described in any one of claims 1-5, 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. Using the gamma detector, collect the gamma energy spectrum generated by the interaction between thermal neutrons and the steel wire rope to obtain the energy spectrum sequence S(z, E) distributed along the axial position z. S4. The leakage magnetic field signal B(z) is filtered and denoised to obtain the processed signal den(B(z)). Based on the metal cross-sectional area S and the outermost steel wire diameter R, the electromagnetic corrosion index is calculated. ; S5. Analyze the energy spectrum sequence S(z, E) and extract the net count of the characteristic peaks of hydrogen and iron. and Calculate the neutron corrosion index ; S6. Construct a joint calibration model to integrate the electromagnetic corrosion indexes. and the neutron corrosion index Data fusion was performed to calculate a comprehensive quantitative index of corrosion. ; S7. Based on the aforementioned comprehensive corrosion quantification index , Corrosion width Based on the corrosion depth d, the rusted area inside the wire rope is reconstructed and visualized in three dimensions.

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

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

9. A method for non-destructive testing of internal corrosion in steel wire ropes according to claim 6, characterized in that, The comprehensive corrosion quantification index mentioned in step S6 Calculated using the following linear weighted fusion model: Among them, the weighting coefficient , , and constant term The determination was made by calibration and fitting of samples with known corrosion levels.

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