An in-situ blind hole profile ultrasonic three-dimensional imaging method

Abstract

The application discloses an in-situ blind hole profile ultrasonic three-dimensional imaging method, which comprises the following steps: S1: according to the position of a target blind hole to be detected, a circular main scanning path concentric with the blind hole is planned; S2: the main scanning path is divided into a plurality of auxiliary scanning points at fixed angle intervals, at each auxiliary scanning point, probe rotation collection is performed with the auxiliary scanning point as the center and at fixed angle intervals, and a linear array phased array ultrasonic probe is used to acquire data in a phased array full focusing ultrasonic imaging mode; S3: the rotation collection data of each auxiliary scanning point is screened according to a preset judgment criterion, optimal data points are determined, and the collection angle, imaging profile and front distance information of the optimal data points are stored; and S4: all auxiliary scanning points are traversed, three-dimensional modeling is performed based on the information of all the optimal data points, and the three-dimensional profile of the blind hole is obtained.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic nondestructive testing technology, and more specifically, to an in-situ blind hole contour ultrasonic three-dimensional imaging method. Background Technology

[0002] In engineering machinery applications, blind hole structures are frequently used to facilitate the assembly of different components. These blind holes are secured by the smooth section of a connecting bolt extending into the hole. For example... Figure 1a , Figure 1b As shown, during service, components are subjected to heavy loads, vibrations, impacts, and environmental corrosion, which can easily cause wear between the bolt's smooth section and the circular hole. This alters the shape of the circular hole, leading to poor assemblability, structural instability, and significant safety hazards. Because blind holes are internally enclosed, structurally obstructed, and extremely inaccessible, conventional visual methods cannot inspect their outlines without disassembling the relevant components. This has long been a major engineering challenge, posing significant safety risks and making it difficult to predict potential faults. Therefore, there is an urgent need to develop an in-situ blind hole outline inspection method suitable for components that do not require disassembly. Summary of the Invention

[0003] This invention provides an in-situ blind hole contour ultrasonic three-dimensional imaging method to solve the technical problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides an in-situ blind hole contour ultrasonic three-dimensional imaging method, which includes the following steps: S1: Based on the location of the blind hole to be inspected, plan a circular main scanning path concentric with the blind hole; S2: The main scanning path is divided into multiple auxiliary scanning points at fixed angle intervals. At each auxiliary scanning point, the probe is rotated and acquired at fixed angle intervals with the auxiliary scanning point as the center. A linear array phased array ultrasonic probe is used to acquire data in phased array full-focus ultrasonic imaging mode. S3: Filter the rotational acquisition data of each auxiliary scanning point according to the preset judgment criteria, determine the preferred data points and store their acquisition angle, imaging contour and leading edge distance information; S4: Traverse all auxiliary scanning points, perform 3D modeling based on all preferred data point information, and obtain the 3D contour of the blind hole.

[0005] In one embodiment of the present invention, optionally, the phased array full-focus ultrasound imaging mode includes full-focus full-matrix acquisition and full-focus reconstruction, wherein: Full-focus full-matrix acquisition involves the probe sequentially exciting individual array elements to emit ultrasonic waves, and all array elements synchronously receiving the echoes to obtain M×M sets of scanning data, where M is the number of probe chips; Full-focus reconstruction involves gridding the detection area, calculating the propagation time of the sound wave for each element pixel, aligning the delay of the A-scan signal, and superimposing the amplitude to generate a focused image.

[0006] In one embodiment of the present invention, optionally, the determination criteria are as follows: select three fixed depth positions in the depth direction of the blind hole, compare the contour front edge values ​​of the corresponding depths at each acquisition angle, and take the angle with the most occurrences of the minimum front edge value at the three depths as the preferred angle; if the minimum angles corresponding to the three depths are different, then the angle with the minimum front edge value at the median depth is the preferred angle.

[0007] In one embodiment of the present invention, optionally, the three fixed depth positions are 10 mm, 17.5 mm and 25 mm away from the upper surface of the component under inspection.

[0008] In one embodiment of the present invention, optionally, the main scanning path is divided into 16 auxiliary scanning points, and the angular interval between adjacent auxiliary scanning points is 22.5°.

[0009] In one embodiment of the present invention, optionally, the auxiliary scanning path of each auxiliary scanning point is as follows: taking the line connecting the auxiliary scanning point and the center of the blind hole as a reference, deflecting to both sides 3 times each, deflecting 5° each time, and performing a total of 7 data acquisitions.

[0010] In one embodiment of the present invention, optionally, the linear phased array ultrasonic probe has 64 elements, the element spacing is 0.35 mm, the frequency is 5 MHz, the active aperture is 22.3 mm, and the passive aperture is 8 mm.

[0011] In one embodiment of the present invention, optionally, the region of interest for full-focus reconstruction is a 25mm×20mm rectangular area located 10mm~30mm from the front end of the probe and 5mm~30mm from the upper surface of the component.

[0012] In one embodiment of the present invention, optionally, the three-dimensional modeling is performed using UG or SOLIDWORKS software, the imaging contour lines of all auxiliary scanning points are constructed in three-dimensional space according to the acquisition angle and the distance of the leading edge, and the contour lines are connected in three dimensions to form a three-dimensional model of the blind hole.

[0013] In one embodiment of the present invention, optionally, the three-dimensional contour of the blind hole is compared with a preset standard circular hole model, and the wear amount, ellipticity, radial deformation amount and local defect size of the blind hole are automatically calculated and output to form an ultrasonic three-dimensional imaging report of the blind hole contour.

[0014] The in-situ blind hole contour ultrasonic three-dimensional imaging method provided by this invention has the following beneficial technical effects: In the prior art, if it is necessary to observe the wear condition of blind hole structures, the unit needs to be shut down for maintenance, and the assembly between different components needs to be completely disassembled to expose the blind hole. The wear condition of the blind hole is then observed visually. This method requires a lot of manpower and resources, and requires the unit to be shut down for maintenance, resulting in poor inspection convenience. With this invention, blind hole ultrasonic detection can be performed on the outer surface without disassembling the components, accurately restoring the three-dimensional shape of the screw hole. This can be performed during temporary unit shutdowns, greatly saving manpower and resources for inspection, improving the convenience of implementation, and is of great significance for ensuring the safe and stable operation of the unit. Attached Figure Description

[0015] Figure 1a This is an appearance drawing of a blind hole + bolt fixing assembly in the prior art; Figure 1b This is a cross-sectional view of a blind hole + bolt fixing assembly in the prior art; Figure 2 This is a perspective view of the components and probe in the second embodiment; Figure 3 This is a side view of the components and probe in the second embodiment; Figure 4 This is a top view of the components and probe in the second embodiment; Figure 5 This is a partial view of the auxiliary scanning points in the second embodiment; Figure 6 This is a phased array full-focus ultrasound imaging image at a certain angle of the auxiliary scanning point in the second embodiment; Figure 7a This is a side view of the ultrasound imaging contour line at a certain angle of the auxiliary scanning point in the second embodiment; Figure 7b This is a top view of the ultrasound imaging contour line at a certain angle of the auxiliary scanning point in the second embodiment; Figure 8 This is a schematic diagram of three-dimensional imaging of the 16 contour lines in the second embodiment; Figure 9 This is a perspective view of the components and probe in the third embodiment; Figure 10 This is a side view of the components and probe in the third embodiment; Figure 11 This is a top view of the components and probe in the third embodiment; Figure 12 This is a partial view of the auxiliary scanning points in the third embodiment; Figure 13 This is a phased array full-focus ultrasound imaging image at a certain angle of the auxiliary scanning point in the third embodiment; Figure 14aThis is a side view of the ultrasound imaging contour line at a certain angle of the auxiliary scanning point in the third embodiment; Figure 14b This is a top view of the ultrasound imaging contour line at a certain angle of the auxiliary scanning point in the third embodiment; Figure 15 This is a schematic diagram of three-dimensional imaging of the 16 contour lines in the third embodiment; Figure 16 This is a flowchart of the in-situ blind hole contour ultrasonic three-dimensional imaging method in the first embodiment. Detailed Implementation

[0016] This invention primarily addresses the challenge in existing engineering applications where blind hole + bolt-fixed assembly structures cannot achieve detailed inspection and precise three-dimensional imaging of the blind hole contour wear condition without disassembling the components.

[0017] First embodiment: This invention provides an in-situ blind hole contour ultrasonic three-dimensional imaging method, such as... Figure 16 As shown, it includes the following steps: S1: Based on the location of the blind hole to be inspected, plan a circular main scanning path concentric with the blind hole; In this embodiment, the main scanning path can be divided into 16 auxiliary scanning points, with an angular interval of 22.5° between adjacent auxiliary scanning points. The auxiliary scanning path for each auxiliary scanning point is as follows: taking the line connecting the auxiliary scanning point and the center of the blind hole as a reference, it deflects to both sides 3 times, with each deflection being 5°, for a total of 7 data acquisitions.

[0018] S2: The main scanning path is divided into multiple auxiliary scanning points at fixed angle intervals. At each auxiliary scanning point, the probe is rotated and acquired at fixed angle intervals with the auxiliary scanning point as the center. A linear array phased array ultrasonic probe is used to acquire data in phased array full-focus ultrasonic imaging mode. In this embodiment, the phased array full-focus ultrasound imaging mode includes, for example, full-focus full-matrix acquisition and full-focus reconstruction, wherein: Full-focus full-matrix acquisition involves the probe sequentially exciting individual array elements to emit ultrasonic waves, and all array elements synchronously receiving the echoes to obtain M×M sets of scanning data, where M is the number of probe chips; Full-focus reconstruction involves gridding the detection area, calculating the propagation time of the sound wave for each element pixel, aligning the delay of the A-scan signal, and superimposing the amplitude to generate a focused image.

[0019] The area of ​​interest for full-focus reconstruction is, for example, a 25mm × 20mm rectangular area 10mm to 30mm from the front end of the probe and 5mm to 30mm from the upper surface of the component.

[0020] In addition, the linear phased array ultrasonic probe has, for example, 64 elements with an element spacing of 0.35 mm, a frequency of 5 MHz, an active aperture of 22.3 mm, and a passive aperture of 8 mm.

[0021] S3: Filter the rotational acquisition data of each auxiliary scanning point according to the preset judgment criteria, determine the preferred data points and store their acquisition angle, imaging contour and leading edge distance information; In this embodiment, the judgment criteria can be preset as follows: Select three fixed depth positions along the depth direction of the blind hole, compare the contour front edge values ​​of the corresponding depths at each acquisition angle, and select the angle with the most frequent occurrences of the minimum front edge value at the three depths as the preferred angle; if the minimum angles corresponding to the three depths are all different, then the angle with the minimum front edge value at the median depth is the preferred angle. The three fixed depth positions are, for example, 10mm, 17.5mm, and 25mm from the upper surface of the inspected component.

[0022] S4: Traverse all auxiliary scanning points, perform 3D modeling based on all preferred data point information, and obtain the 3D contour of the blind hole.

[0023] In this embodiment, 3D modeling can be performed using software such as UG or SOLIDWORKS. The imaging contours of all auxiliary scanning points are constructed in 3D space according to the acquisition angle and the distance to the leading edge, and the contours are connected in 3D to form a 3D model of the blind hole.

[0024] Furthermore, for example, the three-dimensional contour of the blind hole can be compared with a preset standard circular hole model, and the wear amount, ellipticity, radial deformation amount and local defect size of the blind hole can be automatically calculated and output to form an ultrasonic three-dimensional imaging report of the blind hole contour.

[0025] Second embodiment: The engineering case is a double-layer flat panel structure. The upper panel is 25mm thick and the lower panel is 18mm thick. The two panels are fixed together using blind holes and screws. The blind holes are 15mm in diameter and 15mm deep, and the distance from the blind zone on the surface of the upper panel is 10mm. The screw rod section that mates with the upper panel is 15mm high and 14.9mm in diameter. The screw thread section that mates with the lower panel is 28mm high.

[0026] During service, the upper and lower plates are subjected to heavy loads, vibrations, impacts, and environmental corrosion, causing wear on the screw shafts and blind holes. This leads to changes in the size and shape of the blind holes, poor assembly of the upper and lower plates, and instability of the overall component structure, posing significant safety hazards to engineering applications. Because blind holes are internally enclosed, structurally obstructed, and extremely inaccessible, conventional visual inspection methods cannot achieve the desired circular hole contour without disassembling the upper and lower plates. This invention proposes an in-situ ultrasonic three-dimensional imaging method for blind hole contours, enabling detailed inspection and precise three-dimensional imaging of the wear condition of circular holes. In this case, the blind circular hole was not worn and retained its original, complete circular shape. The specific steps are as follows: Step 1: Based on the location of the target circular hole to be inspected, plan the main scanning path. The main scanning path is located on the upper surface of the upper plate and is a circle with a diameter of 45mm concentric with the blind circular hole. Figure 2 and Figure 3 As shown.

[0027] Step 2: Divide the main scanning path circle into 16 auxiliary scanning points at 22.5° intervals. At each auxiliary scanning point, execute the auxiliary scanning path. The auxiliary scanning path is a straight line connecting the current auxiliary scanning point and the center of the blind hole circle, with a 5° interval on each side, and perform probe data acquisition 3 times in total.

[0028] A 64-element linear phased array ultrasonic probe with an element spacing of 0.35 mm, a frequency of 5 MHz, an active aperture of 22.3 mm, and a passive aperture of 8 mm was selected. Acquisition was performed using phased array full-focusing ultrasonic imaging mode, divided into two processes: full-focusing full-matrix acquisition (FMC) and full-focusing reconstruction (TFM). Full-focusing full-matrix acquisition (FMC) refers to the phased array probe sequentially exciting individual elements to emit ultrasonic waves, with all elements simultaneously receiving the echoes, obtaining 64×64 groups of A-scan data, covering all emitted waves. Receiver Combination. Total Focused Reconstruction (TFM) meshes the region of interest, which is a 25mm × 20mm rectangular area located 10mm–30mm from the probe tip and 5mm–30mm from the top surface of the upper plate. The acoustic propagation time of all element pairs is calculated pixel-by-pixel. Delay alignment and amplitude superposition are performed on each A-scan signal to generate the focused amplitude for that pixel. All pixels are traversed to synthesize a full-area focused image, such as… Figure 4 and Figure 5 As shown.

[0029] Step 3: The seven sets of phased array full-focus scan data acquired at 5° intervals at each auxiliary scanning point are evaluated. The evaluation criteria are as follows: using the leading edge values ​​of the contour at three depths (10mm, 17.5mm, and 25mm from the upper surface of the plate), the data point with the angle value that has the smallest leading edge value at the three depths most frequently is selected as the preferred data point. However, if the angle with the smallest leading edge value at the three depths is three different angle values, then the data point with the smallest leading edge value at the median depth (17.5mm) is selected as the preferred data point. Figure 6 As shown.

[0030] Specific selection examples are as follows: (1) If the minimum leading edge value is 0° at 10mm, 0° at 17.5mm, and 0° at 25mm, then the angle at which the minimum leading edge value appears most frequently at these three depths is 0°, which appears 3 times. Therefore, the data with 0° is selected as the preferred data point. In this embodiment, the blind circular hole did not show wear and was not circular. Therefore, the data with 0° is selected as the preferred data point for all 16 auxiliary scanning points around the circumference.

[0031] (2) For example, the minimum front edge value is 0° at 10mm, the minimum front edge value is 0° at 17.5mm, and the minimum front edge value is -5° at 25mm. That is, the angle with the minimum front edge value at the three depths that appears most often is 0°, which appears twice. Therefore, the data with 0° is selected as the preferred data point. (3) If the minimum frontal value at 10mm is -5°, the minimum frontal value at 17.5mm is 0°, and the minimum frontal value at 25mm is 5°, that is, the angles with the minimum frontal values ​​at the three depths are three different angle values, then the data point with the minimum frontal value of 0° at the median depth, i.e., 17.5mm, is selected as the preferred data point.

[0032] The acquisition angle, imaging profile, and frontal distance of the selected data points are stored. Step 4: Following steps 1 through 3, perform a 3D model of the acquisition angles, imaging contours, and leading-edge distances of all 16 auxiliary scanning points stored in the database to obtain the 3D contour shape of the circular hole. Specifically, using drawing software such as UG or SOLIDWORKS, create the imaging contour lines of the 16 auxiliary scanning points in 3D space according to the acquisition angles, leading-edge distances, etc., and then connect the 16 imaging contour lines in 3D to form a 3D model, thus obtaining the 3D contour shape of the circular hole. Figure 7a , Figure 7b and Figure 8 As shown.

[0033] Third embodiment: The engineering case is a double-layer flat panel structure. The upper panel is 25mm thick and the lower panel is 18mm thick. The middle is fixed by blind holes and screws. The diameter of the blind holes is 15mm. The two sides of the blind holes are worn and elongated into a racetrack shape, with an elongation of 15mm on each side. The depth of the holes is 15mm. The distance from the blind zone on the surface of the upper panel is 10mm. The screw rod section that mates with the upper panel is 15mm high and 14.9mm in diameter. The screw thread section that mates with the lower panel is 28mm high.

[0034] During service, the upper and lower plates are subjected to heavy loads, vibrations, impacts, and environmental corrosion, causing wear on the screw shafts and blind holes. This leads to changes in the size and shape of the blind holes, poor assemblability of the upper and lower plates, and overall structural instability, posing significant safety hazards to engineering applications. Because blind holes are enclosed, structurally obstructed, and extremely inaccessible, conventional visual inspection methods cannot inspect their outlines without disassembling the upper and lower plates. This invention proposes an in-situ ultrasonic three-dimensional imaging method for blind hole outlines, enabling detailed inspection and precise three-dimensional imaging of the wear condition of the blind hole outline. This case involves a blind circular hole worn from both sides, resembling a runway circle. The specific steps are as follows: Step 1: Based on the location of the target circular hole to be inspected, plan the main scanning path. The main scanning path is located on the upper surface of the upper plate and is a circle with a diameter of 45mm concentric with the blind circular hole. Figure 9 and Figure 10 As shown.

[0035] Step 2: Divide the main scanning path circle into 16 auxiliary scanning points at 22.5° intervals. At each auxiliary scanning point, execute the auxiliary scanning path. The auxiliary scanning path is a straight line connecting the current auxiliary scanning point and the center of the blind hole circle, with a 5° interval on each side, and perform probe data acquisition 3 times in total.

[0036] A 64-element linear phased array ultrasonic probe with an element spacing of 0.35 mm, a frequency of 5 MHz, an active aperture of 22.3 mm, and a passive aperture of 8 mm was selected. Acquisition was performed using phased array full-focusing ultrasonic imaging mode, divided into two processes: full-focusing full-matrix acquisition (FMC) and full-focusing reconstruction (TFM). Full-focusing full-matrix acquisition (FMC) refers to the phased array probe sequentially exciting individual elements to emit ultrasonic waves, with all elements simultaneously receiving the echoes, obtaining 64×64 groups of A-scan data, covering all emitted waves. Receiver Combination. Total Focused Reconstruction (TFM) meshes the region of interest, which is a 25mm × 20mm rectangular area located 10mm–30mm from the probe tip and 5mm–30mm from the top surface of the upper plate. The acoustic propagation time of all element pairs is calculated pixel-by-pixel. Delay alignment and amplitude superposition are performed on each A-scan signal to generate the focused amplitude for that pixel. All pixels are traversed to synthesize a full-area focused image, such as… Figure 11 and Figure 12 As shown.

[0037] Step 3: The seven sets of phased array full-focus scan data acquired at 5° intervals at each auxiliary scanning point are evaluated. The evaluation criteria are as follows: using the leading edge values ​​of the contour at three depths (10mm, 17.5mm, and 25mm from the upper surface of the plate), the data point with the angle value that has the smallest leading edge value at the three depths most frequently is selected as the preferred data point. However, if the angle with the smallest leading edge value at the three depths is three different angle values, then the data point with the smallest leading edge value at the median depth (17.5mm) is selected as the preferred data point. Figure 13 As shown.

[0038] Specific selection examples are as follows: (1) If the minimum leading edge value is 0° at 10mm, 0° at 17.5mm, and 0° at 25mm, then the angle at which the minimum leading edge value appears most frequently at these three depths is 0°, which appears 3 times. Therefore, the data with 0° is selected as the preferred data point. In this embodiment, the blind circular hole did not show wear and was not circular. Therefore, the data with 0° is selected as the preferred data point for all 16 auxiliary scanning points around the circumference.

[0039] (2) For example, the minimum front edge value is 0° at 10mm, the minimum front edge value is 0° at 17.5mm, and the minimum front edge value is -5° at 25mm. That is, the angle with the minimum front edge value at the three depths that appears most often is 0°, which appears twice. Therefore, the data with 0° is selected as the preferred data point. (3) If the minimum frontal value at 10mm is -5°, the minimum frontal value at 17.5mm is 0°, and the minimum frontal value at 25mm is 5°, that is, the angles with the minimum frontal values ​​at the three depths are three different angle values, then the data point with the minimum frontal value of 0° at the median depth, i.e., 17.5mm, is selected as the preferred data point.

[0040] The acquisition angle, imaging profile, and frontal distance of the selected data points are stored. Step 4: Following steps 1 through 3, perform a 3D model of the acquisition angles, imaging contours, and leading-edge distances of all 16 auxiliary scanning points stored in the database to obtain the 3D contour shape of the circular hole. Specifically, using drawing software such as UG or SOLIDWORKS, create the imaging contour lines of the 16 auxiliary scanning points in 3D space according to the acquisition angles, leading-edge distances, etc., and then connect the 16 imaging contour lines in 3D to form a 3D model, thus obtaining the 3D contour shape of the circular hole after wear and stretching. Figure 14a , 14b and Figure 15 As shown.

[0041] The in-situ blind hole contour ultrasonic three-dimensional imaging method provided by this invention has the following beneficial technical effects: In the prior art, if it is necessary to observe the wear condition of blind hole structures, the unit needs to be shut down for maintenance, and the assembly between different components needs to be completely disassembled to expose the blind hole. The wear condition of the blind hole is then observed visually. This method requires a lot of manpower and resources, and requires the unit to be shut down for maintenance, resulting in poor inspection convenience. With this invention, blind hole ultrasonic detection can be performed on the outer surface without disassembling the components, accurately restoring the three-dimensional shape of the screw hole. This can be performed during temporary unit shutdowns, greatly saving manpower and resources for inspection, improving the convenience of implementation, and is of great significance for ensuring the safe and stable operation of the unit.

Claims

1. An in-situ blind hole contour ultrasonic three-dimensional imaging method, characterized in that, Includes the following steps: S1: Based on the location of the blind hole to be inspected, plan a circular main scanning path concentric with the blind hole; S2: The main scanning path is divided into multiple auxiliary scanning points at fixed angle intervals. At each auxiliary scanning point, the probe is rotated and acquired at fixed angle intervals with the auxiliary scanning point as the center. A linear array phased array ultrasonic probe is used to acquire data in phased array full-focus ultrasonic imaging mode. S3: Filter the rotational acquisition data of each auxiliary scanning point according to the preset judgment criteria, determine the preferred data points and store their acquisition angle, imaging contour and leading edge distance information; S4: Traverse all auxiliary scanning points, perform 3D modeling based on all preferred data point information, and obtain the 3D contour of the blind hole.

2. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, Phased array full-focus ultrasound imaging modes include full-focus full-matrix acquisition and full-focus reconstruction, wherein: Full-focus full-matrix acquisition involves the probe sequentially exciting individual array elements to emit ultrasonic waves, and all array elements synchronously receiving the echoes to obtain M×M sets of scanning data, where M is the number of probe chips; Full-focus reconstruction involves gridding the detection area, calculating the propagation time of the sound wave for each element pixel, aligning the delay of the A-scan signal, and superimposing the amplitude to generate a focused image.

3. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, The judgment criteria are as follows: Select three fixed depth positions along the depth direction of the blind hole, compare the contour front edge values ​​of the corresponding depths at each acquisition angle, and take the angle with the minimum front edge value at the three depths that appears most frequently as the preferred angle; if the minimum angles corresponding to the three depths are different, then the angle with the minimum front edge value at the median depth is the preferred angle.

4. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 3, characterized in that, The three fixed depth positions are 10mm, 17.5mm, and 25mm from the upper surface of the inspected part, respectively.

5. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, The main scanning path is divided into 16 auxiliary scanning points, with an angular interval of 22.5° between adjacent auxiliary scanning points.

6. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, The auxiliary scanning path for each auxiliary scanning point is as follows: taking the line connecting the auxiliary scanning point and the center of the blind hole as the reference, deflect 3 times to each side, each time by 5°, for a total of 7 data acquisitions.

7. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, The linear phased array ultrasonic probe has 64 elements with an element spacing of 0.35 mm, a frequency of 5 MHz, an active aperture of 22.3 mm, and a passive aperture of 8 mm.

8. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 2, characterized in that, The area of ​​interest for full-focus reconstruction is a 25mm × 20mm rectangular area located 10mm to 30mm from the probe tip and 5mm to 30mm from the upper surface of the component.

9. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 1, characterized in that, 3D modeling is performed using UG or SOLIDWORKS software. The imaging contours of all auxiliary scanning points are constructed in 3D space according to the acquisition angle and the distance to the leading edge, and the contours are connected in 3D to form a 3D model of the blind hole.

10. The in-situ blind hole contour ultrasonic three-dimensional imaging method according to claim 3, characterized in that, The three-dimensional contour of the blind hole is compared with a preset standard circular hole model, and the wear amount, ellipticity, radial deformation amount and local defect size of the blind hole are automatically calculated and output to form an ultrasonic three-dimensional imaging report of the blind hole contour.

Images