Internal and external injury distinguishing method and device based on multi-layer signal change slope ratio

Abstract

The invention relates to an internal and external injury distinguishing method and device based on a multi-layer signal change slope ratio. The method comprises the following steps: carrying out magnetization treatment on a thick-wall steel pipe to be detected to obtain a magnetic saturation thick-wall steel pipe; performing defect detection on the magnetic saturation thick-wall steel pipe to obtain a plurality of groups of magnetic conductivity disturbance signal peak values; calculating a change slope ratio between every two magnetic conductivity disturbance signals according to the peak values of the multiple groups of magnetic conductivity disturbance signals; and determining whether the current position of the thick-wall steel pipe is external damage or internal damage according to the change slope ratio and a preset change slope ratio threshold value. According to the invention, the thick-wall steel pipe to be detected is magnetized, and the change slope ratio of the magnetic conductivity disturbance signals in the magnetic saturation thick-wall steel pipe at the damaged position can be determined through the magnetic conductivity disturbance signals received by the detection probes at different positions; the external damage and the internal damage of the thick-wall steel pipe are recognized by comparing the change slope with the preset change slope ratio threshold value, high-precision rapid recognition is achieved, and no damage is caused to the human body.

Description

Technical Field

[0001] The present invention relates to the technical field of steel pipe detection, and particularly to a method and device for distinguishing internal and external injuries based on the slope ratio of multi-layer signal changes. Background Art

[0002] Thick-walled pipes are widely used in engineering fields such as water, gas, petroleum, and construction, occupying an important position. During the production and use of steel pipes, due to various factors such as tensile and compressive stresses and corrosion, various types of defects may form on their inner and outer walls. For the non-destructive testing of steel pipes, differentiating between internal and external wall injuries is conducive to improving the flaw detection accuracy and reducing harmfulness. Therefore, differentiating between internal and external injuries of ferromagnetic materials is very important.

[0003] In the prior art, methods for detecting thick-walled pipes include ultrasonic testing, radiographic testing, conventional eddy current testing, pulsed eddy current testing, and magnetic flux leakage testing. In ultrasonic testing, electromagnetic ultrasonic transducers can be used to excite various types of ultrasounds for detection; radiographic testing is completed by irradiating with radioactive rays; conventional eddy current testing refers to a non-destructive testing method that uses the principle of electromagnetic induction to non-destructively evaluate certain properties of conductive materials and their workpieces by measuring the changes in induced eddy currents in the workpiece to be tested or to detect defects; pulsed eddy current testing has a rich frequency spectrum and can extract the difference characteristics of internal and external defects; in magnetic flux leakage testing, there are relatively rich detection methods for internal and external defects.

[0004] However, common ultrasonic testing requires a coupling agent during the testing process; radiographic testing requires relatively high testing conditions and high testing costs, is generally not used for the detection of steel pipes, and causes relatively large harm to the human body; conventional eddy current testing has a skin effect and is mainly used for detecting internal and external defects of thin-walled materials; pulsed eddy current testing has a low penetration depth in materials with high permeability and cannot perform the detection work on thick-walled steel pipes; for thick-walled steel pipes in magnetic flux leakage testing, the magnetizer has a large volume, high power consumption, and is prone to missing small internal wall defects. Summary of the Invention

[0005] In view of this, it is necessary to provide a method and device for distinguishing internal and external injuries based on the slope ratio of multi-layer signal changes to solve the problems in the prior art that it is difficult to accurately and quickly identify internal and external injuries of thick-walled steel pipes, or the existing identification methods cause damage to the bodies of testing personnel.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for distinguishing internal and external injuries based on the slope ratio of multi-layer signal changes, including:

[0008] Magnetize the thick-walled steel pipe to be tested to obtain a magnetically saturated thick-walled steel pipe;

[0009] Defect detection is performed on a magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals;

[0010] Calculate the change slope ratio between every two magnetic permeability perturbation signals based on the multiple groups of peak values of magnetic permeability perturbation signals;

[0011] Determine whether the current position of the thick-walled steel pipe is an external damage or an internal damage based on the change slope ratio and a preset change slope ratio threshold.

[0012] Furthermore, defect detection is performed on a magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals, including:

[0013] Scan the outer surface of the magnetically saturated thick-walled steel pipe with a detection probe to detect the surface magnetic permeability of the magnetically saturated thick-walled steel pipe;

[0014] When the detection probe detects a damaged part of the magnetically saturated thick-walled steel pipe, output multiple groups of initial magnetic permeability perturbation signals;

[0015] Preprocess the initial magnetic permeability perturbation signals to obtain multiple groups of peak values of magnetic permeability perturbation signals.

[0016] Furthermore, preprocess the initial magnetic permeability perturbation signals to obtain multiple groups of peak values of magnetic permeability perturbation signals, including:

[0017] Perform filtering on the initial magnetic permeability perturbation signals to filter out the interference signals in the initial magnetic permeability perturbation signals;

[0018] Amplify the filtered initial magnetic permeability perturbation signals to obtain multiple groups of magnetic permeability perturbation signals;

[0019] Determine multiple groups of peak values of magnetic permeability perturbation signals from the multiple groups of magnetic permeability perturbation signals.

[0020] Furthermore, when the detection probe detects a damaged part of the magnetically saturated thick-walled steel pipe, output multiple groups of initial magnetic permeability perturbation signals, including:

[0021] Detect multiple groups of voltage signals at the damaged part of the magnetically saturated thick-walled steel pipe;

[0022] Convert multiple groups of initial magnetic permeability perturbation signals at the damaged part according to the multiple groups of voltage signals.

[0023] Furthermore, calculate the change slope ratio between every two magnetic permeability perturbation signals based on the multiple groups of peak values of magnetic permeability perturbation signals, including:

[0024] Calculate multiple groups of change slopes between every two magnetic permeability perturbation signals based on the multiple groups of peak values of magnetic permeability perturbation signals;

[0025] Take the ratio between the slopes of multiple groups of varying slopes pairwise as the slope ratio of variation.

[0026] Further, calculate multiple groups of slopes of variation between pairwise magnetic permeability perturbation signals based on the peaks of multiple groups of magnetic permeability perturbation signals, including:

[0027] Take the slope between the peaks of different groups of magnetic permeability perturbation signals pairwise as the current two groups of slopes of variation.

[0028] Further, determine whether the current position of the thick-walled steel pipe is an external damage or an internal damage based on the slope ratio of variation and a preset slope ratio threshold of variation, including:

[0029] Set a preset slope ratio threshold of variation for distinguishing external damage from internal damage;

[0030] When the slope ratio of variation is greater than the preset slope ratio threshold of variation, the current position of the thick-walled steel pipe is an internal damage;

[0031] When the slope ratio of variation is less than the preset slope ratio threshold of variation, the current position of the thick-walled steel pipe is an external damage.

[0032] Further, perform magnetization treatment on the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe, including:

[0033] Apply a preset magnetization current to the thick-walled steel pipe to be detected through a magnetizer until the thick-walled steel pipe to be detected is in a saturated state to obtain a magnetically saturated thick-walled steel pipe.

[0034] Further, the saturated state is a magnetically saturated state.

[0035] In a second aspect, the present invention also provides a device for distinguishing internal and external damages based on the slope ratio of multiple-layer signal variations, including:

[0036] A magnetization module, configured to perform magnetization treatment on the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe;

[0037] A detection module, configured to perform defect detection on the magnetically saturated thick-walled steel pipe to obtain the peaks of multiple groups of magnetic permeability perturbation signals;

[0038] A calculation module, configured to calculate the slope ratio of variation between pairwise magnetic permeability perturbation signals based on the peaks of multiple groups of magnetic permeability perturbation signals;

[0039] A judgment module, configured to determine whether the current position of the thick-walled steel pipe is an external damage or an internal damage based on the slope ratio of variation and a preset slope ratio threshold of variation.

[0040] The beneficial effects of adopting the above embodiments are as follows: The present invention relates to a method and device for distinguishing internal and external injuries based on the change slope ratio of multi-layer signals. The method includes: magnetizing the to-be-detected thick-walled steel pipe to obtain a magnetically saturated thick-walled steel pipe; performing defect detection on the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals; calculating the change slope ratio between every two of the magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals; and determining whether the current position of the thick-walled steel pipe is an external injury or an internal injury according to the change slope ratio and a preset change slope ratio threshold. The present invention magnetizes the to-be-detected thick-walled steel pipe to the saturated state to obtain a magnetically saturated thick-walled steel pipe. The change slope ratio of the magnetic permeability perturbation signals in the magnetically saturated thick-walled steel pipe at the position where the damage occurs can be determined by the magnetic permeability perturbation signals received by the probes at different positions on the magnetically saturated thick-walled steel pipe. Then, the change slope ratio is compared with the preset change slope ratio threshold, so as to identify the external and internal injuries of the thick-walled steel pipe, achieving the purpose of quickly and accurately identifying the external and internal injuries of the thick-walled steel pipe, and not causing damage to the human body. Description of the Drawings

[0041] Figure 1 It is a schematic flowchart of an embodiment of the method for distinguishing internal and external injuries based on the change slope ratio of multi-layer signals provided by the present invention;

[0042] Figure 2 Provided by the present invention Figure 1 It is a schematic flowchart of an embodiment of step S102 in

[0043] Figure 3 Provided by the present invention Figure 2 It is a schematic flowchart of an embodiment of step S203 in

[0044] Figure 4 Provided by the present invention Figure 2 It is a schematic flowchart of an embodiment of step S202 in

[0045] Figure 5 Provided by the present invention Figure 1 It is a schematic flowchart of an embodiment of step S104 in

[0046] Figure 6 It is a schematic diagram of the relationship of an embodiment of the change of the slope ratio of internal and external injuries with the increase of the damage depth of the thick-walled steel pipe provided by the present invention;

[0047] Figure 7 It is a schematic diagram of the relationship of an embodiment of the change of the slope ratio of internal and external injuries with the increase of the damage width of the thick-walled steel pipe provided by the present invention;

[0048] Figure 8 It is a schematic structural diagram of an embodiment of the device for distinguishing internal and external injuries based on the change slope ratio of multi-layer signals provided by the present invention. Detailed implementation manners

[0049] The following will specifically describe the preferred embodiments of the present invention with reference to the accompanying drawings. The accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0050] Before elaborating on the embodiments of the present invention, the following explanations are provided for related terms:

[0051] Thick-walled steel pipes, also known as thick-walled tubes, refer to steel pipes with an outer diameter to wall thickness ratio less than 20.

[0052] In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined.

[0053] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0054] The present invention provides a method and device for distinguishing internal and external injuries based on the ratio of multi-layer signal change slopes, which will be described separately below.

[0055] Please refer to Figure 1 , Figure 1 is a schematic flowchart of an embodiment of the method for distinguishing internal and external injuries based on the ratio of multi-layer signal change slopes provided by the present invention. A specific embodiment of the present invention discloses a method for distinguishing internal and external injuries based on the ratio of multi-layer signal change slopes, including:

[0056] S101. Magnetize the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe;

[0057] S102. Detect defects in the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals;

[0058] S103. Calculate the change slope ratio between every two of the magnetic permeability perturbation signals based on the multiple groups of peak values of magnetic permeability perturbation signals;

[0059] S104. Determine whether the current position of the thick-walled steel pipe is an external injury or an internal injury based on the change slope ratio and a preset change slope ratio threshold.

[0060] In the above embodiments, under normal circumstances, the thick-walled steel pipe does not have magnetism and thus the magnetic permeability cannot be detected from it. Therefore, it is first necessary to magnetize the thick-walled steel pipe to be detected to reach the saturation state, thereby obtaining a magnetically saturated thick-walled steel pipe. The magnetic permeability in the non-damaged magnetically saturated thick-walled steel pipe is uniform, and damage in different parts will cause changes in the magnetic permeability of the magnetically saturated thick-walled steel pipe.

[0061] The magnetically saturated thick-walled steel pipe is detected by a detection probe. It needs to be excited to collect a response, and it is difficult to directly collect the magnetic permeability. Through research, it is found that the magnetic permeability has a positive correlation with the voltage in the magnetically saturated thick-walled steel pipe. Therefore, by studying the voltage in the magnetically saturated thick-walled steel pipe, the change of the magnetic permeability disturbance signal in the magnetically saturated thick-walled steel pipe is determined, and further multiple groups of magnetic permeability disturbance signal peaks are determined.

[0062] The change slope ratio of the magnetic permeability disturbance signal in the magnetically saturated thick-walled steel pipe reflects that there is a damaged part here, and the influence of internal damage and external damage of the magnetically saturated thick-walled steel pipe on the magnetic permeability disturbance in the magnetically saturated thick-walled steel pipe is different. Therefore, it is necessary to calculate the change slope ratio to judge whether the current position of the thick-walled steel pipe is external damage or internal damage.

[0063] The preset change slope ratio threshold can generally be determined based on a large number of experiments or adjusted according to actual needs. The present invention does not make further restrictions on this. By comparing the size relationship between the preset change slope ratio threshold and the change slope ratio, it can be determined whether the current position of the thick-walled steel pipe is external damage or internal damage.

[0064] Compared with the prior art, an internal and external injury discrimination method based on the change slope ratio of multi-layer signals provided in this embodiment includes: magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe; performing defect detection on the magnetically saturated thick-walled steel pipe to obtain multiple groups of magnetic permeability disturbance signal peaks; calculating the change slope ratio between every two of the magnetic permeability disturbance signals according to the multiple groups of magnetic permeability disturbance signal peaks; and determining whether the current position of the thick-walled steel pipe is external damage or internal damage according to the change slope ratio and the preset change slope ratio threshold. The present invention magnetizes the thick-walled steel pipe to be detected to the saturation state to obtain a magnetically saturated thick-walled steel pipe. The change slope ratio of the magnetic permeability disturbance signal in the magnetically saturated thick-walled steel pipe at the position where damage occurs can be determined through the magnetic permeability disturbance signals received by the probes at different positions on the magnetically saturated thick-walled steel pipe. Then, the change slope ratio is compared with the preset change slope ratio threshold, so as to identify the external damage and internal damage of the thick-walled steel pipe, achieving the purpose of quickly and accurately identifying the external damage and internal damage of the thick-walled steel pipe, and not causing damage to the human body.

[0065] Please refer to Figure 2 , Figure 2 provided by the present inventionFigure 1 Flow schematic diagram of an embodiment of step S102. In some embodiments of the present invention, multiple groups of peak values of magnetic permeability perturbation signals are obtained by defect detection of a magnetically saturated thick-walled steel pipe, including:

[0066] S201: Scan the outer surface of the magnetically saturated thick-walled steel pipe with a detection probe to detect the surface magnetic permeability of the magnetically saturated thick-walled steel pipe;

[0067] S202: Output multiple groups of initial magnetic permeability perturbation signals when the detection probe detects the damaged part of the magnetically saturated thick-walled steel pipe;

[0068] S203: Preprocess the initial magnetic permeability perturbation signals to obtain multiple groups of peak values of magnetic permeability perturbation signals.

[0069] In the above embodiment, the detection probe includes an excitation coil and a detection coil. As a preferred embodiment, in the present invention, the center lines of one excitation coil and three groups of differential detection coils are respectively arranged on the outer surface of the thick-walled steel pipe along the normal direction, and scanned along the outer surface of the magnetically saturated thick-walled steel pipe to determine the surface magnetic permeability of the magnetically saturated thick-walled steel pipe.

[0070] The magnetic permeability perturbation signals obtained by the detection coil of the detection probe are initial magnetic permeability perturbation signals, which may contain some interference signals and are difficult to use directly. Therefore, in the present invention, it is also necessary to perform a certain preprocessing on them to determine multiple groups of peak values of magnetic permeability perturbation signals.

[0071] Please refer to Figure 3 , Figure 3 provided by the present invention Figure 2 Flow schematic diagram of an embodiment of step S203. In some embodiments of the present invention, multiple groups of peak values of magnetic permeability perturbation signals are obtained by preprocessing the initial magnetic permeability perturbation signals, including:

[0072] S301: Filter the initial magnetic permeability perturbation signals to filter out the interference signals in the initial magnetic permeability perturbation signals;

[0073] S302: Amplify the filtered initial magnetic permeability perturbation signals to obtain multiple groups of magnetic permeability perturbation signals;

[0074] S303: Determine multiple groups of peak values of magnetic permeability perturbation signals from multiple groups of magnetic permeability perturbation signals.

[0075] In the above embodiment, the present invention can adopt various different ways for filtering processing, as long as the interference signals in the initial magnetic permeability perturbation signals can be filtered out. The present invention does not make further limitations on this.

[0076] After that, the amplified module amplifies the filtered initial permeability perturbation signal to obtain multiple groups of permeability perturbation signals, so as to perform calculations based on the multiple groups of permeability perturbation signals, and thus accurately determine the peaks of the multiple groups of permeability perturbation signals from the multiple groups of permeability perturbation signals, improving the accuracy of damage location judgment.

[0077] Please refer to Figure 4 , Figure 4 provided by the present invention Figure 2 is a schematic flowchart of an embodiment of step S202 in [the present invention]. In some embodiments of the present invention, when the detection probe detects the damage location of the magnetically saturated thick-walled steel pipe, it outputs multiple groups of initial permeability perturbation signals, including:

[0078] S401. Detect multiple groups of voltage signals at the damage location of the magnetically saturated thick-walled steel pipe;

[0079] S402. Convert multiple groups of initial permeability perturbation signals at the damage location according to the multiple groups of voltage signals.

[0080] In the above embodiment, the permeability in the magnetically saturated thick-walled steel pipe is positively correlated with the voltage. Therefore, the voltage can be used to reflect the change in permeability, and multiple groups of initial permeability perturbation signals at the damage location are determined by determining the specific relationship between the permeability and the voltage.

[0081] In some embodiments of the present invention, calculating the change slope ratio between two pairs of permeability perturbation signals according to the peaks of multiple groups of permeability perturbation signals includes:

[0082] Calculating multiple groups of change slopes between two pairs of permeability perturbation signals according to the peaks of multiple groups of permeability perturbation signals;

[0083] Taking the ratio between two pairs of multiple groups of change slopes as the change slope ratio.

[0084] In some embodiments of the present invention, calculating multiple groups of change slopes between two pairs of permeability perturbation signals according to the peaks of multiple groups of permeability perturbation signals includes:

[0085] Taking the slope between two peaks of different groups of permeability perturbation signals as the current two groups of change slopes.

[0086] In the above embodiment, the present invention uses three detection coils at different positions, and three groups of permeability perturbation signal peaks will be detected, which are respectively denoted as the first channel, the second channel, and the third channel. The calculation formula for multiple groups of change slopes between two pairs of permeability perturbation signals is as follows:

[0087] K 1-2 = -2(V 峰峰值_1 - V 峰峰值_2 );

[0088] K 2-3 = -2(V 峰峰值_2 - V 峰峰值_3 ));

[0089] Among them, V 峰峰值_1 is the peak value of the permeability perturbation signal when the first channel is at a lift-off of 0, V 峰峰值_2 is the peak value of the permeability perturbation signal when the second channel is at a lift-off of 0.5 mm, V 峰峰值_3 is the peak value of the permeability perturbation signal when the third channel is at a lift-off of 1 mm, and K 1-2 is the change slope of the permeability perturbation signal from the first channel to the second channel, and K 2-3 is the change slope of the permeability perturbation signal from the second channel to the third channel.

[0090] It can be understood that the detection coils in the present invention can also be set to other numbers according to actual needs, and the present invention does not make further limitations in this regard.

[0091] The calculation formula of the change slope ratio is as follows:

[0092] K 1-2 / 2-3 = K 1-2 / K 2-3 ;

[0093] Among them, K 1-2 / 2-3 is the ratio between the change slope of the permeability perturbation signal from the first channel to the second channel and the change slope of the permeability perturbation signal from the second channel to the third channel.

[0094] Please refer to Figure 5 , Figure 5 which is a schematic flowchart of an embodiment of step S104 in Figure 1 provided by the present invention. In some embodiments of the present invention, determining whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and the preset change slope ratio threshold includes:

[0095] S501. Set a preset change slope ratio threshold for distinguishing external damage from internal damage;

[0096] S502. When the change slope ratio is greater than the preset change slope ratio threshold, the current position of the thick-walled steel pipe is an internal damage;

[0097] S503. When the change slope ratio is less than the preset change slope ratio threshold, the current position of the thick-walled steel pipe is an external damage.

[0098] In the above embodiment, the preset change slope ratio threshold for distinguishing internal and external injuries is set as K standard, It should be noted that the preset change slope ratio threshold can be adjusted according to the actual situation, or can be directly calculated and determined according to the size of the thick-walled steel pipe. As a preferred embodiment, the preset change slope ratio threshold in the present invention is selected as 1.3.

[0099] K 1-2 / 2-3 reflects the internal damage condition of the thick-walled steel pipe. When K 1-2 / 2-3 is greater than K standard , it can be determined that the current position of the thick-walled steel pipe is internal damage. When K 1-2 / 2-3 is less than K standard , it can be determined that the current position of the thick-walled steel pipe is external damage.

[0100] Please refer to Figure 6 , Figure 6 , which is a schematic diagram of the relationship of an embodiment provided by the present invention regarding the change in the slope ratio of internal and external injuries with the increase in the damage depth of the thick-walled steel pipe. Please refer to Figure 7 , Figure 7 , which is a schematic diagram of the relationship of an embodiment provided by the present invention regarding the change in the slope ratio of internal and external injuries with the increase in the damage width of the thick-walled steel pipe. It can be seen from Figure 6 and Figure 7 that the external damage of the thick-walled steel pipe changes more significantly than the internal damage. Therefore, its slope change is greater.

[0101] In some embodiments of the present invention, magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe includes:

[0102] Applying a preset magnetization current to the thick-walled steel pipe to be detected through a magnetizer until the thick-walled steel pipe to be detected is in a saturated state to obtain a magnetically saturated thick-walled steel pipe.

[0103] In some embodiments of the present invention, the saturated state is a magnetically saturated state.

[0104] In the above embodiment, the magnetizer can be a through-type DC coil magnetizer or a yoke magnetizer. The magnetization current magnetizes the thick-walled steel pipe to be detected to a saturated state, and a permeability disturbance region is formed in the subsurface layer of the thick-walled steel pipe at the defective part. Three detection coils are respectively located at 0 mm, 0.5 mm, and 1 mm away from the surface of the steel pipe to be detected to receive signals and output along the magnetization direction.

[0105] In order to better implement the internal and external injury discrimination method based on the multi-layer signal change slope ratio in the embodiments of the present invention, on the basis of the internal and external injury discrimination method based on the multi-layer signal change slope ratio, correspondingly, please refer to Figure 8 , Figure 8 , which is a schematic structural diagram of an embodiment of the internal and external injury discrimination device based on the multi-layer signal change slope ratio provided by the present invention. The embodiments of the present invention provide an internal and external injury discrimination device 800 based on the multi-layer signal change slope ratio, including:

[0106] A magnetization module 810 for magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe;

[0107] A detection module 820 for defect detecting the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals;

[0108] A calculation module 830 for calculating the change slope ratio between every two of the magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals;

[0109] A judgment module 840 for determining whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and a preset change slope ratio threshold.

[0110] It should be noted here that: The device 800 provided in the above embodiment can implement the technical solutions described in the above method embodiments. For the specific implementation principles of the above modules or units, reference can be made to the corresponding content in the above method embodiments, which will not be elaborated here.

[0111] In summary, a method and a device for distinguishing internal and external injuries based on the change slope ratio of multi-layer signals provided in this embodiment. The method includes: magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe; defect detecting the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals; calculating the change slope ratio between every two of the magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals; determining whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and a preset change slope ratio threshold. The present invention magnetizes the thick-walled steel pipe to be detected to the saturated state to obtain a magnetically saturated thick-walled steel pipe. By detecting the magnetic permeability at different positions of the magnetically saturated thick-walled steel pipe, the change slope ratio of the magnetic permeability perturbation signals at the positions where damage occurs can be determined. Then, the change slope ratio is compared with the preset change slope ratio threshold, so as to identify the external damage and internal damage of the thick-walled steel pipe, achieving the purpose of quickly and accurately identifying the external damage and internal damage of the thick-walled steel pipe, and causing no damage to the human body.

[0112] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for differentiating internal and external injuries based on the ratio of multi-layer signal change slopes, characterized in that Including: Magnetize the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe; Perform defect detection on the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals Calculate the change slope ratio between every two magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals; Determine whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and a preset change slope ratio threshold.

2. The method for differentiating internal and external injuries based on the ratio of multi-layer signal change slopes according to claim 1, characterized in that, The performing defect detection on the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals includes: Sweep the detection probe along the outer surface of the magnetically saturated thick-walled steel pipe to detect the magnetic permeability perturbation caused by the defect of the magnetically saturated thick-walled steel pipe; Output multiple groups of initial magnetic permeability perturbation signals when the detection probe detects the damaged part of the magnetically saturated thick-walled steel pipe; Perform preprocessing on the initial magnetic permeability perturbation signals to obtain multiple groups of peak values of magnetic permeability perturbation signals.

3. The method for differentiating internal and external injuries based on the ratio of the slopes of multi-layer signal changes according to claim 2, wherein The performing preprocessing on the initial magnetic permeability perturbation signals to obtain multiple groups of peak values of magnetic permeability perturbation signals includes: Perform filtering processing on the initial magnetic permeability perturbation signals to filter out the interference signals in the initial magnetic permeability perturbation signals; Perform amplification processing on the filtered initial magnetic permeability perturbation signals to obtain multiple groups of magnetic permeability perturbation signals; Determine multiple groups of peak values of magnetic permeability perturbation signals from the multiple groups of magnetic permeability perturbation signals.

4. The method for differentiating internal and external injuries based on the ratio of the slopes of multi-layer signal changes according to claim 2, wherein, The outputting multiple groups of initial magnetic permeability perturbation signals when the detection probe detects the damaged part of the magnetically saturated thick-walled steel pipe includes: Detect multiple groups of voltage signals of the damaged part of the magnetically saturated thick-walled steel pipe; Convert the multiple groups of voltage signals into multiple groups of initial magnetic permeability perturbation signals of the damaged part.

5. The method for distinguishing internal and external injuries based on the ratio of multi-layer signal change slopes according to claim 1, characterized in that, The calculating the change slope ratio between every two magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals includes: Calculate multiple groups of change slopes between every two magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals; Take the ratio between every two of the multiple groups of change slopes as the change slope ratio.

6. The method for differentiating internal and external injuries based on the ratio of the slopes of multi-layer signal changes according to claim 5, wherein The calculating multiple groups of change slopes between every two magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals includes: Take the slope between every two peak values of different groups of magnetic permeability perturbation signals as the current two groups of change slopes.

7. The method for differentiating internal and external injuries based on the ratio of the slopes of multi-layer signal changes according to claim 1, wherein, The determining whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and a preset change slope ratio threshold includes: Set a preset change slope ratio threshold for distinguishing external damage from internal damage; When the change slope ratio is greater than the preset change slope ratio threshold, the current position of the thick-walled steel pipe is an internal damage; When the change slope ratio is less than the preset change slope ratio threshold, the current position of the thick-walled steel pipe is an external damage.

8. The method for differentiating internal and external injuries based on the ratio of multi-layer signal change slopes according to claim 1, wherein The magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe includes: Apply a preset magnetization current to the thick-walled steel pipe to be detected through a magnetizer until the thick-walled steel pipe to be detected is in a saturated state to obtain a magnetically saturated thick-walled steel pipe.

9. The method for differentiating internal and external injuries based on the ratio of multi-layer signal change slopes according to claim 8, characterized in that, The saturated state is a magnetic saturation state.

10. An internal and external injury differentiation device based on the ratio of the slopes of multi-layer signal changes, characterized in that, Including: A magnetization module for magnetizing the thick-walled steel pipe to be detected to obtain a magnetically saturated thick-walled steel pipe; A detection module, configured to perform defect detection on the magnetically saturated thick-walled steel pipe to obtain multiple groups of peak values of magnetic permeability perturbation signals; A calculation module, configured to calculate the change slope ratio between any two magnetic permeability perturbation signals according to the multiple groups of peak values of magnetic permeability perturbation signals; A judgment module, configured to determine whether the current position of the thick-walled steel pipe is an external damage or an internal damage according to the change slope ratio and a preset change slope ratio threshold.

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