A bolt detection method, device and equipment based on pulse echo ultrasound

Abstract

The present application provides a bolt detection method, device and equipment based on pulse echo ultrasound. The method provided by the present application includes: fabricating a bolt test block with a plurality of preset cut grooves, and determining the placement angle of a target detector based on the bolt detection range; detecting the preset cut grooves based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time, and the ultrasonic reflection signal of the preset cut groove has a mutation. Determine the first change trend of the flaw detection sensitivity according to the mutation amplitude of the ultrasonic reflection signal of the preset cut grooves successively scanned by the target detector, detect the bolt to be measured based on the target detector, and compare the obtained measured waveband with the flaw detection sensitivity to determine the detection result of the bolt to be measured. The bolt detection method, device and equipment based on pulse echo ultrasound provided by the present application are used to accurately and reliably detect bolts.

Description

Technical Field

[0001] This application relates to the technical field of ultrasonic testing, and in particular, to a bolt detection method, device, and equipment based on pulse-echo ultrasound. Background Art

[0002] Bolts are important fasteners in pressure-bearing equipment and are widely used. In pressure pipeline systems and stationary pressure vessels, a large number of bolts are used as fasteners, such as the connection between the tube sheet and the shell of a large heat exchanger, the connection between the manhole cover plate and the seat ring of a large container, and the connection between the container nozzle and the pressure pipeline, all of which play an important connection role. Therefore, once a fatigue crack or fracture occurs in the bolt, it may lead to danger or disaster in the factory.

[0003] Existing bolt detection methods rely on magnetic particle testing, penetrant testing, and other testing techniques after the bolts are disassembled. After the studs are cleaned one by one, their damage and crack conditions are inspected, with a focus on checking for circumferential cracks in the threads and transition parts. Nondestructive testing is carried out if necessary. This method has a cumbersome process, and during the process of disassembling and installing the bolts, if the operation is improper, it will cause a gap between the bolt and the bolt hole, thereby increasing the probability of damage during use, reducing the service life, and even threatening the safe operation of the pressure-bearing equipment. During the disassembly process of the bolts, it is difficult to clean the roots of the threads that need to be inspected by magnetic particle and penetrant testing, and it is also difficult to remove the rust in the grooves, which will have a great impact on the testing. During the process of removing bolts from large equipment, it will result in certain high-altitude operations, threatening personal safety. Moreover, the process method of detecting bolts by removing them requires the factory to stop production, and there are a large number of bolts, which will lead to too long testing time and affect the enterprise's efficiency. It cannot meet the requirements for bolt detection in actual production. Summary of the Invention

[0004] In view of this, this application provides a bolt detection method, device, and equipment based on pulse-echo ultrasound to accurately and reliably detect bolts.

[0005] Specifically, this application is implemented through the following technical solutions:

[0006] In the first aspect of this application, a bolt detection method based on pulse-echo ultrasound is provided, and the method includes:

[0007] Fabricate a bolt test block, the bolt test block is provided with a plurality of preset cut grooves, and each of the preset cut grooves is not parallel to the side wall of the bolt test block;

[0008] Determine the placement angle of the target detector based on the bolt detection range; the target detector has a longitudinal wave inclined probe, and the inclined probe forms a first included angle with the center line of the target detector, and the first included angle is less than or equal to 10°. The placement angle is the included angle between the center line of the target detector and the side wall of the bolt. At this placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest;

[0009] Detect the preset notch based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time. The ultrasonic reflection signal of the preset notch undergoes a mutation. Determine the first change trend of the flaw detection sensitivity according to the mutation amplitude of the ultrasonic reflection signal of the preset notch sequentially scanned by the target detector, and generate the flaw detection sensitivity according to the first change trend;

[0010] Detect the bolt to be tested based on the target detector, and compare the obtained measured waveband with the flaw detection sensitivity to determine the detection result of the bolt to be tested.

[0011] The second aspect of this application provides a bolt detection device based on pulse echo ultrasonics. The device includes a manufacturing module, a determination module, an acquisition module, and a detection module; among them,

[0012] The manufacturing module is used to manufacture a bolt test block. The bolt test block is provided with a plurality of preset notches, and each preset notch is not parallel to the side wall of the bolt test block;

[0013] The determination module is used to determine the placement angle of the target detector based on the bolt detection range; the target detector has a longitudinal wave inclined probe, and the inclined probe forms a first included angle with the center line of the target detector, and the first included angle is less than or equal to 10°. The placement angle is the included angle between the center line of the target detector and the side wall of the bolt. At this placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest;

[0014] The acquisition module is used to detect the preset notch based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time. The ultrasonic reflection signal of the preset notch undergoes a mutation. Determine the first change trend of the flaw detection sensitivity according to the mutation amplitude of the ultrasonic reflection signal of the preset notch sequentially scanned by the target detector, and generate the flaw detection sensitivity according to the first change trend;

[0015] The detection module is used to detect the bolt to be tested based on the target detector, and compare the obtained measured waveband with the flaw detection sensitivity to determine the detection result of the bolt to be tested.

[0016] In a third aspect of the present application, a bolt detection device based on pulse - echo ultrasound is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of any of the methods provided in the first aspect of the present application are implemented.

[0017] In a fourth aspect of the present application, a computer - readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the steps of any of the methods provided in the first aspect of the present application are implemented.

[0018] The bolt detection method and device based on pulse - echo ultrasound provided by the present application can complete on - line detection and flaw detection without disassembling the bolts in the pressure - bearing equipment, avoiding the safety risks, cumbersome operations, and problems affecting the normal operation of the equipment that may be brought about by disassembling bolts in the traditional method. Further, when setting the oblique cutting angle of the probe, the damaged grooves in the bolts are usually difficult to be parallel to the bolt surface. Therefore, in order to maximize the reflected signal and improve the detection ability. If transverse waves are used for detection, two different reflected waves (transverse waves and longitudinal waves) will be obtained, and the longitudinal waves among them will interfere with the detection result. However, the method provided by the present invention sets the oblique cutting angle and performs detection through pure longitudinal waves. The obtained reflected wave is also a pure longitudinal wave without the interference of other reflected waves, and accurate detection results can be obtained. Further, by precisely controlling parameters such as the probe angle, moving speed, and gain, the depth and position of the defect can be accurately measured, improving the detection accuracy and reliability. Further, the sensitivity curve can be directly compared with the measured waveband without other processing, which can greatly increase the simplicity of detection, that is, the detection of bolts can be completed without other operations such as processing and conversion. At the same time, a bolt test block with a preset groove of a certain depth and angle is used to obtain the flaw detection sensitivity, ensuring the accuracy of the detection result. In this way, through on - line detection of the bolt to be measured, the detection result of the bolt to be measured can be obtained accurately and reliably. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of the bolt detection method based on pulse - echo ultrasound shown in an exemplary embodiment of the present application;

[0020] Figure 2 It is a detection schematic diagram of the target detector shown in an exemplary embodiment of the present application;

[0021] Figure 3 It is a schematic diagram of the flaw detection sensitivity shown in an exemplary embodiment of the present application;

[0022] Figure 4 It is a hardware structure diagram of a bolt detection device based on pulse - echo ultrasound where the bolt detection device based on pulse - echo ultrasound of the present application is located;

[0023] Figure 5 This is a schematic structural diagram of the first embodiment of the bolt detection device based on pulse echo ultrasound provided by this application. Specific embodiments

[0024] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0025] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a", "said", and "the" used in this application are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0026] It should be understood that although terms such as first, second, and third may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0027] This application provides a bolt detection method, device, and equipment based on pulse echo ultrasound to accurately and reliably detect bolts.

[0028] Specific embodiments are given below to introduce the technical solutions of this application in detail.

[0029] Figure 1 This is a flowchart of the bolt detection method based on pulse echo ultrasound shown in an exemplary embodiment of this application. Please refer to Figure 1 , the method provided in this embodiment may include:

[0030] S101. Fabricate a bolt test block, where the bolt test block is provided with a plurality of preset cut grooves, and each of the preset cut grooves is not parallel to the side wall of the bolt test block.

[0031] Specifically, the bolt test block is a specimen used to simulate the actual bolt structure for non-destructive testing experiments such as ultrasonic testing. It should be noted that the bolt test block has the same size, shape, and material as the bolt to be tested, so as to simulate the sound wave propagation and reflection characteristics in the actual detection environment. Specifically, a brand-new bolt of the same model as the bolt to be tested can be selected as the bolt test block.

[0032] Furthermore, the preset notch is a groove with a specific depth artificially machined on the bolt test block, used to simulate possible defects (such as cracks, fatigue damage, etc.) in the bolt. It should be noted that the specific position and quantity of the preset notch are set according to actual needs and are not limited in this embodiment. Specifically, 3 preset notches can be set, and the notch depth is 1.0 mm - 3.0 mm.

[0033] It should be noted that the main defect to be detected is the circumferential crack at the root of the thread. Therefore, when making the preset notch, it can be made in the style of the circumferential crack at the root of the thread.

[0034] Furthermore, to prevent the side wall of the bolt test block from interfering with the preset notch, the preset notch is set to be non-parallel to the side wall. It should be noted that through the preset notch that is non-parallel to the side wall, the circumferential crack at the root of the bolt in the actual scenario can be better simulated.

[0035] Specifically, in this step, according to the material characteristics of the bolt to be tested, a suitable bolt test block is selected, and technical means such as machining or wire cutting are used to machine the preset notch on the bolt test block. Then, surface treatment such as grinding and cleaning is performed on the machined bolt test block to remove impurities such as burrs and oil stains generated during the machining process. Ensure that the surface of the test block is flat and smooth for subsequent detection operations.

[0036] S102. Determine the placement angle of the target detector based on the bolt detection range; the target detector has a longitudinal wave inclined probe, and the inclined probe forms a first included angle with the center line of the target detector, and the first included angle is less than or equal to 10°. The placement angle is the included angle between the center line of the target detector and the side wall of the bolt. At this placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest.

[0037] Specifically, the bolt detection range is the area inside the bolt that can be covered by ultrasonic detection. The bolt detection range refers to the detection target area for effectively detecting defects inside the bolt. Specifically, all the side wall threads of the bolt can be used as the bolt detection range.

[0038] Further, the target detector is a device for ultrasonic detection of bolts. It integrates a longitudinal wave inclined probe and other necessary detection elements, and can emit and receive ultrasonic signals, thereby performing non-destructive detection on bolts.

[0039] Further, the longitudinal wave inclined probe can be a small-angle longitudinal wave inclined probe of a plexiglass wedge block and a transducer (wafer). Specifically, when implemented, a pulsed echo ultrasonic flaw detector with the model number HS700 can be selected as the target detector. The size of the longitudinal wave inclined probe is 5 - 7 mm × 5 - 7 mm.

[0040] It should be noted that the specific frequency of the sound wave emitted by the target detector is determined according to actual needs. In this embodiment, it is not limited herein. Specifically, when implemented, the specific frequency of the sound wave emitted by the target detector can be determined according to the depth of the bolt to be detected to prevent an excessive frequency from being unable to fully detect the bolt. For example, in one embodiment, the specific frequency of the sound wave emitted by the target detector is determined to be 5 MHz.

[0041] Further, the longitudinal wave inclined probe can emit and receive longitudinal waves, responsible for converting electrical energy into ultrasonic energy and emitting it, and at the same time receiving the ultrasonic reflection signal reflected back from inside the bolt. It should be noted that by emitting longitudinal waves through the longitudinal wave inclined probe, the thread detection of the bolt is ensured. If transverse waves are used for detection, a large number of reflected waves will be generated on the side wall of the bolt, not only unable to detect the threads of the bolt, but also generating a large number of interference signals.

[0042] Further, the first included angle refers to the included angle between the sound beam axis of the longitudinal wave inclined probe and the center line of the target detector. It should be noted that the size of the first included angle will affect the propagation path and reflection effect of ultrasonic waves inside the bolt. Specifically, when implemented, the first included angle ensures that ultrasonic waves can enter the bolt interior at an appropriate angle and be effectively reflected back, thereby improving the accuracy and reliability of detection. For example, in one embodiment, the first included angle is set to be less than or equal to 10°.

[0043] Specifically, when implemented, the target detector with the adjusted angle is placed on the surface of the bolt test block, and the detection program is started. The target detector will emit ultrasonic signals into the bolt interior and receive the reflected ultrasonic reflection signals for processing and analysis, thereby detecting the situation inside the bolt test block.

[0044] Optionally, the frequency of the target detector is 2 - 10 MHZ, and the placement angle is 5° - 8°.

[0045] The following gives a specific embodiment to introduce the determination process of the placement angle in detail:

[0046] (1) Obtain the distance range between the bolt detection range and the top of the bolt test block, and determine the maximum angle based on the distance range.

[0047] Specifically, the distance range is the spatial distance range between the bolt detection range and the top of the bolt test block. The size of this range determines the initial conditions that need to be considered when the ultrasonic probe emits sound waves.

[0048] In specific implementation, the maximum angle is the maximum inclination angle determined to ensure that the sound wave can effectively cover the entire bolt detection range.

[0049] (2) Determine the minimum angle based on the parameter information of the bolt to be measured; the parameter information at least includes the thread parameter information of the bolt to be measured.

[0050] Specifically, the parameter information is all physical dimensions, structural characteristics, material properties, etc. related to the bolt test block, including but not limited to the diameter, length, thread specification, material, thread parameter information, etc. of the bolt.

[0051] In specific implementation, since the target detector detects from the top of the bolt test block to the bottom of the bolt test block, when the detection angle is too small, the sound wave will not be able to reach the thread of the bolt, resulting in a detection failure.

[0052] (3) Select the placement angle based on the minimum angle and the maximum angle.

[0053] In specific implementation, considering the limiting conditions of the maximum angle and the minimum angle, as well as the actual requirements and effects of the detection, a suitable angle is selected as the placement angle.

[0054] The bolt detection method based on pulse - echo ultrasound provided in this embodiment can ensure that the ultrasonic wave can effectively cover the entire detection range of the bolt by determining the maximum angle, avoiding missed areas, and thus improving the reliability of the detection. Further, when determining the minimum angle, considering the thread parameter information of the bolt can avoid missed detection of the thread by the sound wave during the detection process. In this way, the placement angle is jointly determined by the maximum angle and the minimum angle, ensuring the reliability and accuracy of the bolt inspection.

[0055] Further, by detecting and comparing the height differences between the artificial defect reflection wave and the thread root reflection wave of the probes at different placement angles, a longitudinal wave inclined probe with a suitable angle is selected. The results are shown in Table 1. Table 1 is the detection range of different small - angle inclined probes:

[0056] Table 1

[0057]

[0058] Please continue to refer to Table 1. According to Table 1, it can be determined that among these three placement angles, the actual detection range of 6° is the largest.

[0059] Figure 2 This is a detection schematic diagram of the target detector shown in an exemplary embodiment of the present application. Please refer to Figure 2 , the target detector detects the thread of the bolt at three positions H1, H2, and H3 at the placement angle.

[0060] S103. Detect the preset notch based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time. The ultrasonic reflection signal of the preset notch undergoes a mutation. Determine the first change trend of the flaw detection sensitivity according to the mutation amplitude of the ultrasonic reflection signal of the preset notch sequentially scanned by the target detector, and generate the flaw detection sensitivity according to the first change trend.

[0061] Specifically, when the ultrasonic wave emitted by the target detector encounters different media (such as bolt material and defect), phenomena such as reflection and refraction will occur. These reflected ultrasonic reflection signals are received by the probe and converted into electrical signals for processing and analysis to determine whether there are defects inside the bolt, as well as their position and size.

[0062] Furthermore, the flaw detection sensitivity is the ability of the target detector to detect the minimum defect size or the intensity of the reflection signal. In specific implementation, the flaw detection sensitivity can be represented by the correlation curve between the ultrasonic reflection signal and time. The curve of the flaw detection sensitivity reflects the reflection of defects at different depths or positions on the ultrasonic wave.

[0063] It should be noted that in the flaw detection sensitivity, the horizontal axis is the time when the ultrasonic wave travels, which can be understood as the detection depth; the vertical axis is the magnitude of the reflected wave. When there is a defect in the bolt, the wave height of the ultrasonic reflection signal is higher. If there is no defect, there is only the reflection wave of the thread in the ultrasonic reflection signal. The reflection wave of the thread gradually decreases from high to low, and is a tip at the lowest point. If there is a crack in the middle of the bolt, when the ultrasonic reflection signal gradually decreases, there will suddenly be a very high part at one end. At the same time, the signal behind the crack will be blocked by the crack and no ultrasonic reflection signal can be generated.

[0064] Furthermore, on the bolt test block provided with a preset notch, the trend corresponding to the time and mutation amplitude when the ultrasonic reflection signal mutates when scanning the preset notch is the first change trend, which reflects the propagation characteristics of the ultrasonic wave in the bolt material through the first change trend. When encountering a defect (such as a preset notch), the reflection signal will mutate, so that the position and size of the defect can be determined by analyzing these mutations, and then the flaw detection sensitivity can be determined.

[0065] The following gives a specific embodiment to introduce the acquisition process of the flaw detection sensitivity in detail:

[0066] Detect the first cut groove based on the placement angle, determine the abscissa of the first cut groove according to the detection time of the first cut groove, determine the ordinate of the first cut groove according to the mutation amplitude value of the ultrasonic reflection signal of the first cut groove, determine the coordinates of the cut grooves detected later according to the ordinate of the first cut groove, and connect each cut groove in sequence to obtain the flaw detection sensitivity.

[0067] Another specific embodiment is given below to introduce in detail the process of obtaining the flaw detection sensitivity:

[0068] (1) Arrange the target detector according to the placement angle.

[0069] Specifically, during implementation, according to the preset placement angle, place the target detector on the top of the bolt test block, ensure that the probe is in close contact with the bolt surface and apply an appropriate amount of coupling agent to reduce the attenuation and interference of sound waves.

[0070] (2) Move the target detector at a first speed.

[0071] Specifically, the first speed is the speed at which the target detector moves during ultrasonic detection. By the first speed, it can be ensured that the target detector can scan the bolt test block evenly and stably, so as to capture the reflection signals of all preset cut grooves. It should be noted that the specific value of the first speed is preset according to actual needs and is not limited in this embodiment.

[0072] A specific embodiment is given below to introduce in detail the process of obtaining the first speed:

[0073] (1) Determine the echo time based on the detection parameters of the target detector.

[0074] Specifically, before performing ultrasonic detection, it is first necessary to determine the detection parameters of the target detector.

[0075] Specifically during implementation, determine the time for sending ultrasonic waves to the bolt to be measured and receiving the echo signal through the detection parameters, that is, the echo time. This time reflects the propagation distance and speed of ultrasonic waves inside the bolt.

[0076] (2) Generate a maximum moving speed based on the echo time. The target detector moves and detects at the first speed according to the placement angle, and the first speed is less than the maximum moving speed.

[0077] Specifically during implementation, the first speed can be set to be much less than the speed from the pulse signal emission to reception. In this way, it is prevented that the first speed is too fast and the returned data of the pulse signal cannot be received. For example, in one embodiment, the first speed can be set to 150 mm / s. For another example, in another embodiment, the first speed can be set to 100 - 150 mm / s.

[0078] The bolt detection method based on pulse echo ultrasound provided in this embodiment calculates the maximum moving speed using the echo time, limits the moving speed of the probe during the detection process, avoids detection blind spots or missed detections caused by too fast movement, and further improves the detection accuracy. Further, on the premise of ensuring the detection accuracy, by reasonably setting the first speed of the probe, the detection time can be shortened and the detection efficiency can be improved.

[0079] (3) Detect the ultrasonic reflection signals in the bolt test block and locate the reflection waves at the positions of multiple preset cut grooves.

[0080] Specifically, during the movement of the target detector, the ultrasonic probe emits ultrasonic waves and receives ultrasonic reflection signals. These ultrasonic reflection signals are processed in real time by an oscilloscope and converted into recognizable waveforms and displayed on the oscilloscope screen. By analyzing these waveforms, the positions and sizes of the preset cut grooves inside the bolt test block can be preliminarily judged.

[0081] When specifically implemented, the position where the waveform undergoes a sudden change can be determined as the detected preset cut groove.

[0082] (4) Determine the display positions of the subsequent preset cut grooves in the coordinate axes based on the amplitudes of the ultrasonic reflection signals corresponding to the first preset cut groove.

[0083] Specifically, the reflection waves of each preset cut groove are positioned in the coordinate axes.

[0084] When specifically implemented, taking the amplitude of the reflection wave of the first preset cut groove as a reference point, obtain the process of adjusting the amplitude of the reflection wave of the first preset cut groove, and adjust the amplitudes of the reflection waves of all subsequent preset cut grooves through exactly the same adjustment process to determine the display positions of all ultrasonic reflection signals in the coordinate axes.

[0085] The following gives a specific embodiment to introduce in detail the process of determining the display positions of ultrasonic reflection signals:

[0086] Step 1: Determine the vertical axis of the coordinate axes based on the maximum display range of the display positions, and determine the horizontal axis of the coordinate axes based on the time of receiving the ultrasonic reflection signals, and construct the coordinate system.

[0087] Specifically, the maximum display range is the maximum signal intensity range that the oscilloscope can display. This range is usually fixed and is used to standardize and compare the intensities of different reflection signals.

[0088] Further, when constructing the coordinate system, the maximum display range is used as the maximum value of the vertical axis. In specific implementation, since the display range of the oscilloscope is shown by the wave height of the ultrasonic reflection signal, the vertical axis of the coordinate system is also the wave height of the ultrasonic reflection signal.

[0089] Further, the time required for the ultrasonic wave to be emitted, reflected, and returned to the probe is an important basis for determining the defect position. In specific implementation, when constructing the coordinate system, the time point of receiving the ultrasonic reflection signal is used as the horizontal axis reference of the coordinate axis to represent the depth of the defect in the bolt test block.

[0090] Step 2: Determine the gain compensation value based on the amplitude of the ultrasonic reflection signal corresponding to the first preset notch; the gain compensation value is the ratio that needs to be adjusted for the ultrasonic reflection signal corresponding to the first preset notch to be adjusted to the preset value within the maximum display range.

[0091] Specifically, the specific value of the preset value is set according to actual needs and is not limited in this embodiment. In specific implementation, for example, in one embodiment, the ultrasonic reflection signal corresponding to the first preset notch can be adjusted to 90% of the maximum display range. For another example, in another embodiment, the ultrasonic reflection signal corresponding to the first preset notch can be adjusted to 60 - 80% of the maximum display range.

[0092] In specific implementation, in this step, the amplitude of the ultrasonic reflection signal corresponding to the first preset notch is automatically gain-adjusted to the preset value, and the amount of gain increase or decrease is recorded, which is used to adjust the amplitudes of the ultrasonic reflection signals of all other preset notches according to this gain amount for unified representation in the coordinate system.

[0093] Step 3: Adjust the ultrasonic reflection signals corresponding to the subsequent preset notches based on the gain compensation value to generate the display positions of all the preset notches in the coordinate axis.

[0094] Specifically, the amplitude of the ultrasonic reflection signal corresponding to the subsequent preset notches is adjusted by using the gain value corresponding to the first preset notch.

[0095] Further, the adjusted amplitudes of the ultrasonic reflection signals are mapped to the vertical axis of the coordinate system, and at the same time, their positions on the horizontal axis are determined according to the time of receiving these reflection signals to generate the display positions of all the preset notches in the coordinate axis.

[0096] The bolt detection method based on pulse - echo ultrasound provided by this embodiment constructs a coordinate system and determines the vertical axis and the horizontal axis, enabling the ultrasonic reflection signals of all preset notches to be represented and compared within a unified framework. This helps to standardize the detection process and improve the accuracy and repeatability of the detection results. Further, by adjusting the gain compensation value, it is ensured that the reflection signal of the first preset notch can reach a preset display intensity on the display, providing a reference benchmark for subsequent defect detection and helping to improve the detection sensitivity. In this way, through a unified processing and representation method, the influence of other factors on the detection results is reduced, making the display position more complete and reliable.

[0097] (5) Connect the display positions of each of the said preset notches in the said coordinate axes to obtain the flaw detection sensitivity.

[0098] When specifically implemented, the display positions of each preset notch in the coordinate axes are connected with a smooth curve to obtain the flaw detection sensitivity. It should be noted that this curve of flaw detection sensitivity reflects the reflection of ultrasonic waves by preset notches at different depths or positions, and is an important basis for evaluating the condition of the bolt.

[0099] Figure 3 This is a schematic diagram of the flaw detection sensitivity shown in an exemplary embodiment of this application. Please refer to Figure 3 , the bolt test block has 3 preset notches, obtaining corresponding three coordinates, and through smooth connection, the flaw detection sensitivity as shown in Figure 3 is obtained.

[0100] The bolt detection method based on pulse - echo ultrasound provided by this embodiment performs detection without disassembling the bolt, avoiding possible damages and safety hazards caused by disassembling and reinstalling the bolt, and at the same time saving time and labor costs. Further, detecting at the first speed can ensure that the probe moves uniformly and stably on the surface of the bolt test block or the actual bolt, thus more accurately capturing the ultrasonic reflection signal, preventing incomplete signal capture or omission of defects, and improving the precision and accuracy of the detection. In this way, through the longitudinal wave ultrasonic detection technology of the pulse - echo method, combined with specific instrument settings and probe angles, it is possible to accurately and quickly locate the preset notches of the bolt test block, obtain the corresponding flaw detection sensitivity, and provide guarantee for subsequent accurate bolt detection by ensuring the accuracy and reliability of the flaw detection sensitivity.

[0101] S104. Detect the bolt to be measured based on the target detector, compare the obtained measured waveband with the flaw detection sensitivity, and determine the detection result of the bolt to be measured.

[0102] Specifically, the bolt to be tested refers to the bolt on the pressure-bearing equipment that needs to be nondestructively tested. In specific implementation, the bolt to be tested has the same model as the bolt test block, and the diameter of the bolt to be tested is usually greater than or equal to 36 mm.

[0103] Furthermore, the measured waveband is the waveband formed after processing the ultrasonic signal reflected from inside the bolt when the target detector detects the bolt to be tested.

[0104] In specific implementation, place the target detector on the top of the bolt to be tested, ensure that the probe is in close contact with the bolt surface and apply an appropriate amount of coupling agent to reduce the attenuation and interference of sound waves. Place the probe at the top of the bolt to be tested, and make a sawtooth reciprocating sweep in the outward arc direction of the probe. Compare the obtained measured waveband with the pre-determined flaw detection sensitivity. If the signal intensity of the measured waveband exceeds the flaw detection sensitivity, it indicates that there are defects inside the bolt to be tested, and it is necessary to further analyze and confirm information such as the location, size, and shape of the defects. If the signal intensity of the measured waveband does not exceed the flaw detection sensitivity, it indicates that no obvious defects are found inside the bolt to be tested, and it can be considered to be in good condition.

[0105] The following gives a specific embodiment to introduce in detail the process of obtaining the detection result:

[0106] (1) Determine that the measured waveband is located on the abscissa of the coordinate axis based on the detection position and detection direction of the target detector.

[0107] Specifically, the detection position refers to the specific position when the probe of the target detector scans at the top of the bolt to be tested. It should be noted that the detection position determines the specific point where the ultrasonic wave enters the bolt interior.

[0108] Furthermore, the detection direction refers to the orientation direction when the probe of the target detector moves on the bolt end face. It should be noted that this direction determines the propagation path and reflection path of the ultrasonic wave inside the bolt. In specific implementation, the orientation of the target detector can be determined according to the placement angle, and then it is determined as the detection direction.

[0109] In specific implementation, based on the data when the target detector detects the bolt test block, determine the abscissa of the coordinate axis corresponding to the detection position and detection direction.

[0110] (2) Detect the measured wavebands with the ordinate value greater than the flaw detection sensitivity, and determine the detection result of the bolt to be tested based on the abscissa of the measured waveband, the detection position, and the detection direction.

[0111] Specifically, the numerical magnitudes of the peak height of the measured waveband and the flaw detection sensitivity are compared to determine their values. In specific implementation, when the peak height of the measured waveband is greater than the flaw detection sensitivity, it is considered that there is a defect at the position of the bolt to be measured corresponding to the measured waveband.

[0112] Further, after determining the measured waveband with a defect, the depth of the defect is calculated based on the abscissa, detection position, and detection direction of the measured waveband. In specific implementation, through parameters such as the sound velocity, propagation time, and the angle between the probe and the bolt end face, the product of the sound velocity and the propagation time is multiplied by the cosine value of the angle to obtain the position with a defect. For example, in one embodiment, the depth of the defect is approximately the sound velocity (5900 m / s) × the propagation time (t) of the oscilloscope screen × cosθ; where θ is the placement angle.

[0113] Further, the damaged position on the bolt for testing is prepared by wire cutting technology, and a 6° small-angle longitudinal wave probe is used to detect defects at different depths, and the difference between the measured position and the self-made position is compared (the position is represented by the distance from the vertical direction of the defect to the end). The results are shown in Table 2. Table 2 compares the detection position of the 6° small-angle inclined probe with the actual position:

[0114] Table 2

[0115]

[0116] The bolt detection method based on pulse reflection ultrasound provided in this embodiment can accurately locate the position of internal defects in the bolt by precisely determining the detection position and detection direction of the probe and combining the abscissa information of the measured waveband. This precise positioning helps to reduce false alarms and missed detections and improve the accuracy of detection. Further, based on the abscissa, detection position, and detection direction of the measured waveband to determine the defect depth, considering factors such as the sound velocity, propagation time, and the angle between the probe and the bolt end face, can calculate a relatively accurate defect depth value, providing strong support for subsequent repair and replacement work.

[0117] Optionally, determining the detection result of the bolt to be measured includes:

[0118] Determining the defect waveband where the measured waveband is higher than the flaw detection sensitivity;

[0119] Obtaining the propagation time corresponding to the defect waveband and the cosine value of the placement angle;

[0120] Determining the product of the propagation time, sound velocity, and the cosine value as the depth of the defect of the bolt to be measured.

[0121] Specifically, the part of the measured waveband higher than the flaw detection sensitivity is the position where there are defects in the bolt to be measured. Therefore, this measured waveband can be determined as the defect waveband.

[0122] Furthermore, the wave propagation time corresponding to the defect waveband can be determined by the emission time of the defect waveband and the time of receiving the reflected wave.

[0123] The bolt detection method based on pulse reflection ultrasound provided in this embodiment can directly perform non-destructive testing without disassembling the large-diameter bolts on the pressure-bearing equipment, greatly reducing the workload during the detection process and avoiding equipment downtime and production losses caused by disassembling and installing bolts. By using the longitudinal wave ultrasonic detection with the pulse reflection method, the defects inside the bolts, such as cracks and fatigue damages, can be quickly and accurately located. By precisely controlling the moving speed and direction of the probe and combining with the setting of the flaw detection sensitivity, the accuracy and reliability of the detection results can be ensured.

[0124] Corresponding to the foregoing embodiment of a bolt detection method based on pulse reflection ultrasound, the present application also provides an embodiment of a bolt detection device based on pulse reflection ultrasound.

[0125] The embodiment of the bolt detection device based on pulse reflection ultrasound in the present application can be applied to the bolt detection equipment based on pulse reflection ultrasound. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. Taking software implementation as an example, as a logically meaningful device, it is formed by the processor of the bolt detection equipment based on pulse reflection ultrasound where it is located reading the corresponding computer program instructions in the non-volatile memory into the memory for operation. From the hardware level, as Figure 4 shown, it is a hardware structure diagram of the bolt detection equipment based on pulse reflection ultrasound where the bolt detection device based on pulse reflection ultrasound in the present application is located. Except for Figure 4 the shown processor, memory, network interface, and non-volatile memory, the bolt detection equipment where the device is located in the embodiment usually also includes other hardware according to the actual functions of the bolt detection device based on pulse reflection ultrasound, which will not be elaborated here.

[0126] Figure 5 It is a schematic structural diagram of Embodiment 1 of the bolt detection device based on pulse reflection ultrasound provided in the present application. Please refer to Figure 5 , the device provided in this embodiment includes a production module 510, a determination module 520, an acquisition module 530, and a detection module 540; wherein,

[0127] The production module 510 is used to produce a bolt test block, and the bolt test block is provided with a plurality of preset cut grooves, and each of the preset cut grooves is not parallel to the side wall of the bolt test block;

[0128] The determining module 520 is configured to determine the placement angle of the target detector based on the bolt detection range; the target detector has a longitudinal wave shear wave probe, and the shear wave probe forms a first included angle with the center line of the target detector, and the first included angle is less than or equal to 10°. The placement angle is the included angle between the center line of the target detector and the side wall of the bolt. At the placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest;

[0129] The obtaining module 530 is configured to detect the preset notch based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time. The ultrasonic reflection signal of the preset notch undergoes a mutation. The first change trend of the flaw detection sensitivity is determined according to the mutation amplitude of the ultrasonic reflection signals of the preset notches successively scanned by the target detector, and the flaw detection sensitivity is generated according to the first change trend;

[0130] The detecting module 540 is configured to detect the bolt to be tested based on the target detector, and compare the obtained measured waveband with the flaw detection sensitivity to determine the detection result of the bolt to be tested.

[0131] The device of this embodiment can be used to execute Figure 1 the steps of the method embodiment shown. The specific implementation principle and process are similar and will not be elaborated here.

[0132] Optionally, the obtaining module 530 is specifically configured to arrange the target detector according to the placement angle;

[0133] The obtaining module 530 is further specifically configured to move the target detector at a first speed;

[0134] The obtaining module 530 is further specifically configured to detect the ultrasonic reflection signal in the bolt test block and locate the reflected waves at the positions of multiple preset notches;

[0135] The obtaining module 530 is further specifically configured to determine the display position of the subsequent preset notch in the coordinate axis based on the amplitude of the ultrasonic reflection signal corresponding to the first preset notch;

[0136] The obtaining module 530 is further specifically configured to connect the display positions of each preset notch in the coordinate axis to obtain the flaw detection sensitivity.

[0137] Optionally, the obtaining module 530 is further specifically configured to determine the vertical axis of the coordinate axis based on the maximum display range of the display position, and determine the horizontal axis of the coordinate axis based on the time of receiving the ultrasonic reflection signal, and construct the coordinate system;

[0138] The obtaining module 530 is further specifically configured to determine a gain compensation value based on the amplitude of the ultrasonic reflection signal corresponding to the first preset grooving; the gain compensation value is the ratio that needs to be adjusted for the ultrasonic reflection signal corresponding to the first preset grooving to be adjusted to a preset value within the maximum display range.

[0139] The obtaining module 530 is further specifically configured to adjust the ultrasonic reflection signals corresponding to the subsequent preset grooving based on the gain compensation value, and generate the display positions of all the preset grooving in the coordinate axis.

[0140] Optionally, the determining module 520 is specifically configured to obtain the distance interval between the bolt detection range and the top of the bolt test block, and determine the maximum angle based on the distance interval.

[0141] The determining module 520 is further specifically configured to determine the minimum angle based on the parameter information of the bolt to be detected; the parameter information includes at least the thread parameter information of the bolt to be detected.

[0142] The determining module 520 is further specifically configured to select the placement angle based on the minimum angle and the maximum angle.

[0143] Optionally, the detecting module 540 is specifically configured to determine the abscissa of the measured waveband in the coordinate axis based on the detection position and the detection direction of the target detector.

[0144] The detecting module 540 is further specifically configured to detect the measured waveband whose ordinate value is greater than the flaw detection sensitivity, and determine the detection result of the bolt to be detected based on the abscissa of the measured waveband, the detection position and the detection direction.

[0145] Optionally, the detecting module 540 is further specifically configured to determine the echo time based on the detection parameters of the target detector.

[0146] The detecting module 540 is further specifically configured to generate a maximum moving speed based on the echo time, and the target detector moves and detects at a first speed according to the placement angle, and the first speed is less than the maximum moving speed.

[0147] Optionally, the frequency of the target detector is 2 - 10 MHZ, and the placement angle is 5° - 8°.

[0148] Please continue to refer to Figure 4, this application also provides a bolt detection device based on pulse echo ultrasound, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps of any of the methods provided in the first aspect of this application.

[0149] This application also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the steps of any of the methods provided in this application.

[0150] The implementation process of the functions and roles of each unit in the above device is specifically described in detail in the implementation process of the corresponding steps in the above method, and will not be elaborated here.

[0151] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to the partial descriptions of the method embodiments. The device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this application. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0152] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A bolt detection method based on pulse echo ultrasound, characterized in that, The method includes: Fabricating a bolt test block, the bolt test block being provided with a plurality of preset cut grooves, each of the preset cut grooves being non-parallel to the side wall of the bolt test block; Determining the placement angle of a target detector based on the bolt detection range; the target detector has a longitudinal wave angle probe, the angle probe forms a first angle with the center line of the target detector, the first angle is less than or equal to 10°, the placement angle is the angle between the center line of the target detector and the side wall of the bolt, and at the placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest; Detecting the preset cut grooves based on the placement angle to obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is a correlation curve between an ultrasonic reflection signal and time, the ultrasonic reflection signal of the preset cut groove undergoes a mutation, determining a first change trend of the flaw detection sensitivity according to the mutation amplitude of the ultrasonic reflection signals of the preset cut grooves successively scanned by the target detector, and generating the flaw detection sensitivity according to the first change trend; The detecting the preset cut grooves based on the placement angle to obtain the flaw detection sensitivity of the bolt test block includes: Detecting the first cut groove based on the placement angle, determining the abscissa of the first cut groove according to the detection time of the first cut groove, determining the ordinate of the first cut groove according to the mutation amplitude value of the ultrasonic reflection signal of the first cut groove, determining the coordinates of the cut grooves detected later according to the ordinate of the first cut groove, and connecting each cut groove in sequence to obtain the flaw detection sensitivity; Detecting a bolt to be tested based on the target detector, comparing the obtained measured wave band with the flaw detection sensitivity, and determining the detection result of the bolt to be tested.

2. The method according to claim 1, characterized in that The detecting the preset cut grooves based on the placement angle to obtain the flaw detection sensitivity of the bolt test block includes: Arranging the target detector according to the placement angle; Moving the target detector at a first speed; Detecting the ultrasonic reflection signals in the bolt test block and locating the reflected waves at the positions of a plurality of the preset cut grooves; Determining the display positions of the subsequent preset cut grooves in the coordinate axis based on the amplitude of the ultrasonic reflection signal corresponding to the first preset cut groove; Connecting the display positions of each of the preset cut grooves in the coordinate axis to obtain the flaw detection sensitivity.

3. The method according to claim 2, wherein The determining the display positions of the subsequent preset cut grooves in the coordinate axis based on the amplitude of the reflected wave of the first preset cut groove includes: Determining the vertical axis of the coordinate axis based on the maximum display range of the display positions, determining the horizontal axis of the coordinate axis based on the time of receiving the ultrasonic reflection signal, and constructing a coordinate system; Determining a gain compensation value based on the amplitude of the ultrasonic reflection signal corresponding to the first preset cut groove; the gain compensation value is the ratio that needs to be adjusted for the ultrasonic reflection signal corresponding to the first preset cut groove to be adjusted to a preset value within the maximum display range; Adjusting the ultrasonic reflection signals corresponding to the subsequent preset cut grooves based on the gain compensation value to generate the display positions of all the preset cut grooves in the coordinate axis.

4. The method according to claim 1, wherein Determining the placement angle of the target detector based on the bolt detection range includes: Obtaining the distance interval between the bolt detection range and the top of the bolt test block, and determining the maximum angle based on the distance interval; Determining the minimum angle based on the parameter information of the bolt to be measured; the parameter information includes at least the thread parameter information of the bolt to be measured; Selecting the placement angle based on the minimum angle and the maximum angle.

5. The method according to claim 1, characterized in that Detecting the bolt to be measured based on the target detector, comparing the obtained measured waveband with the flaw detection sensitivity, and determining the detection result of the bolt to be measured, including: Determining that the measured waveband is located on the abscissa of the coordinate axis based on the detection position and detection direction of the target detector; Determining the measured waveband with the ordinate value greater than the flaw detection sensitivity, and determining the detection result of the bolt to be measured based on the abscissa of the measured waveband, the detection position, and the detection direction.

6. The method according to claim 1, wherein Determining the detection result of the bolt to be measured includes: Determining the defect waveband where the measured waveband is higher than the flaw detection sensitivity; Obtaining the propagation time corresponding to the defect waveband and the cosine value of the placement angle; Determining the depth of the defect of the bolt to be measured as the product of the propagation time, the sound velocity, and the cosine value.

7. The method according to claim 1, wherein Detecting the bolt to be measured based on the target detector includes: Determining the echo time based on the detection parameters of the target detector; Generating the maximum moving speed based on the echo time, and the target detector moves and detects at the first speed according to the placement angle, and the first speed is less than the maximum moving speed.

8. The method according to claim 1, wherein The frequency of the target detector is 2 - 10 MHZ, and the placement angle is 5° - 8°.

9. A bolt detection device based on pulse echo ultrasound, characterized in that, The device includes a manufacturing module, a determination module, an acquisition module, and a detection module; wherein, The manufacturing module is used to manufacture a bolt test block, and the bolt test block is provided with a plurality of preset cut grooves, and each preset cut groove is not parallel to the side wall of the bolt test block; The determination module is used to determine the placement angle of the target detector based on the bolt detection range; the target detector has a longitudinal wave inclined probe, and the inclined probe forms a first included angle with the center line of the target detector, and the first included angle is less than or equal to 10°, and the placement angle is the included angle between the center line of the target detector and the side wall of the bolt. At this placement angle, the reflection intensity of the longitudinal wave emitted by the target detector is the largest; The acquisition module is used to detect the preset cut groove based on the placement angle and obtain the flaw detection sensitivity of the bolt test block; the flaw detection sensitivity is the correlation curve between the ultrasonic reflection signal and time, and the ultrasonic reflection signal of the preset cut groove undergoes a mutation. According to the mutation amplitude of the ultrasonic reflection signal of the preset cut groove sequentially scanned by the target detector, the first change trend of the flaw detection sensitivity is determined, and the flaw detection sensitivity is generated according to the first change trend; Detecting the preset cut groove based on the placement angle and obtaining the flaw detection sensitivity of the bolt test block includes: Detect the first grooving based on the placement angle, determine the abscissa of the first grooving according to the detection time of the first grooving, determine the ordinate of the first grooving according to the mutation amplitude value of the ultrasonic reflection signal of the first grooving, determine the coordinates of the grooving detected later according to the ordinate of the first grooving, and connect each grooving in sequence to obtain the flaw detection sensitivity; The detection module is used to detect the bolt to be tested based on the target detector, compare the obtained measured waveband with the flaw detection sensitivity, and determine the detection result of the bolt to be tested.

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