Method for detecting defects in the near-surface zone of a round bar by rotary ultrasound

Abstract

The application provides a rotating ultrasonic detection method for defects in the near surface area of a round bar, and relates to the technical field of material detection. The rotating ultrasonic detection method for defects in the near surface area of a round bar comprises the following steps: selecting a round bar with the same specification as the round bar to be detected as a sample bar, and setting a surface groove and a near-surface transverse hole on the sample bar; emitting ultrasonic waves from an ultrasonic probe to the sample bar to obtain ultrasonic signals corresponding to the surface groove and the near-surface transverse hole; adjusting the parameters of the ultrasonic probe according to the ultrasonic signals, and setting the parameters corresponding to the condition that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent; making the ultrasonic probe scan the round bar to be detected with the set parameters; obtaining the set parameters of the ultrasonic probe corresponding to the condition that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent, so that good scanning signals can be obtained for the surface groove damage and the near-surface transverse hole at the same time during the detection and verification of the near-surface area of the sample bar, the detection reliability is improved, the operation is simple, the success rate is high, and therefore the work efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material detection, in particular to a method for detecting defects in the near-surface area of a round bar by rotary ultrasonic detection. BACKGROUND

[0002] The pulse-echo method of ultrasonic detection is an important tool for evaluating the internal quality of dense materials such as metal materials. This technology transmits ultrasonic waves through a probe and receives ultrasonic wave signals reflected by defects in the workpiece, and then generates intuitive display signals by the device. According to the position and amplitude of the signal parameters, the internal condition of the workpiece can be accurately judged.

[0003] However, the existing detection method cannot determine the appropriate refraction angle for different specifications of round bars, and the verification sensitivity is random. The scanning sensitivity of different shear wave refraction angles for surface defects and near-surface defects of round bars is significantly different, and it is difficult to obtain good scanning signals for surface grooves and subsurface near-surface transverse holes at the same time. The existing detection method is difficult, time-consuming, and has a low success rate for one verification, which affects the work efficiency. SUMMARY

[0004] The present application provides a method for detecting defects in the near-surface area of a round bar by rotary ultrasonic detection, which can obtain good scanning signals for surface grooves and near-surface transverse holes at the same time when detecting and verifying the near-surface area of a sample bar and a bar to be detected, improving the detection reliability, being simple to operate, and improving the work efficiency.

[0005] Embodiments of the present application can be implemented as follows:

[0006] In a first aspect, the present application provides a method for detecting defects in the near-surface area of a round bar by rotary ultrasonic detection, comprising:

[0007] Selecting a round bar with the same specification as the bar to be detected as a sample bar, and setting a surface groove and a near-surface transverse hole on the sample bar;

[0008] Transmitting ultrasonic waves from an ultrasonic probe to the sample bar to obtain ultrasonic signals corresponding to the surface groove and the near-surface transverse hole;

[0009] Adjusting the parameters of the ultrasonic probe according to the ultrasonic signals, and setting the corresponding parameters under the condition that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent;

[0010] Making the ultrasonic probe scan the bar to be detected with the set parameters.

[0011] In an optional embodiment, the setting of the surface groove and the near-surface transverse hole on the sample bar further comprises:

[0012] Setting a surface groove on the surface of the sample bar;

[0013] determining the near-surface transverse hole orientation according to the position of the surface groove.

[0014] In an optional embodiment, the step of determining the near-surface transverse hole orientation according to the position of the surface groove further comprises:

[0015] emitting ultrasonic waves from the ultrasonic probe to the sample rod;

[0016] adjusting the ultrasonic probe so that the refraction angle of the ultrasonic waves in the sample rod is a first preset angle;

[0017] acquiring the maximum scanning depth of the main acoustic axis of the transverse wave corresponding to the ultrasonic waves;

[0018] making a circumferential line with the center of the cross section of the sample rod as the center and passing through the midpoint corresponding to the maximum scanning depth;

[0019] determining the near-surface transverse hole orientation according to the intersection of the circumferential line and the surface groove in the radial direction.

[0020] In an optional embodiment, the first preset angle is the included angle between the refracted path of the ultrasonic waves in the sample rod and the line connecting the refracted point and the center of the sample rod, and the first preset angle is 40°-50°.

[0021] In an optional embodiment, the parameters of the ultrasonic probe include sensitivity and inclination angle.

[0022] In an optional embodiment, the step of adjusting the parameters of the ultrasonic probe according to the ultrasonic signals and setting the corresponding setting parameters in the case that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent further comprises:

[0023] adjusting the inclination angle and the sensitivity of the ultrasonic probe, and setting the sensitivity at this time as the initial sensitivity in the case that the ultrasonic signal of the surface groove displays the maximum amplitude;

[0024] making the ultrasonic probe irradiate at the initial sensitivity, and acquiring the ultrasonic signals of the surface groove and the interface between the coupling water and the sample rod;

[0025] adjusting the ultrasonic probe according to the ultrasonic signals of the surface groove and the interface between the coupling water and the sample rod, so that the refraction angle of the ultrasonic waves in the sample rod reaches a second preset angle.

[0026] In an optional embodiment, the step of adjusting the parameters of the ultrasonic probe according to the ultrasonic signals and setting the corresponding setting parameters in the case that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent further comprises:

[0027] In the case that the ultrasonic wave is irradiated at the second preset angle, the sensitivity of the ultrasonic probe is adjusted, so that the sensitivity at the time when the amplitudes of the ultrasonic signals of the surface groove and the near-surface transverse hole reach consistency is set as the set sensitivity.

[0028] In an optional embodiment, the second preset angle is an included angle between a refractive path of the ultrasonic wave in the sample rod and a line connecting a refractive point and the center of the sample rod, and the second preset angle is 40°-50°.

[0029] In an optional embodiment, the step of causing the ultrasonic probe to scan the sample rod at the set parameters further includes:

[0030] causing the ultrasonic probe to irradiate and scan the sample rod at the second preset angle and the set sensitivity.

[0031] In an optional embodiment, before the step of emitting the ultrasonic wave from the ultrasonic probe to the sample rod, the method further includes:

[0032] filling coupling water between the ultrasonic probe and the sample rod.

[0033] The method for detecting defects in the near-surface region of a round rod by rotating ultrasonic waves provided by the embodiments of the present application has the following beneficial effects: the parameters of the ultrasonic probe are set according to the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole, so that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent, and the set parameters of the ultrasonic probe are obtained, that is, the set parameters of the ultrasonic probe can be set according to the specifications of the sample rod, so that good scanning signals of the surface groove and the near-surface transverse hole are obtained at the same time when the near-surface region of the sample rod and the sample rod to be detected is detected and verified, the detection reliability is improved, the operation is simple, and thus the work efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0035] Figure 1 The flowchart of the method for detecting defects in the near-surface region of a round rod by rotating ultrasonic waves provided by the embodiments of the present application is shown in the figure.

[0036] Figure 2 The schematic diagram of the structure of the sample rod provided by the embodiments of the present application is shown in the figure.

[0037] Figure 3 The sectional view of the sample rod provided by the embodiments of the present application is shown in the figure.

[0038] Figure 4 The structure of the embodiment of the present application is shown in the following figures. Figure 3 The structure of the embodiment of the present application is shown in the following figures.

[0039] Figure: 100-sample rod; 110-surface groove; 120-near-surface transverse hole; 130-cutting part; 200-ultrasonic probe; 210-refracted acoustic wave main acoustic axis; 300-coupling water; 410-ultrasonic signal of surface groove; 420-ultrasonic signal of near-surface transverse hole; 430-ultrasonic signal of coupling water and sample rod interface. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0042] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0043] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0044] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0045] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0046] Pulse echo method ultrasonic testing system is an important tool for evaluating the internal quality of dense materials such as metal materials. This technology transmits ultrasonic waves through a probe, receives ultrasonic wave signals reflected by defects in the workpiece, and then generates intuitive display signals by the device. According to the parameters such as the position and amplitude of the signal, the internal condition of the workpiece can be accurately judged.

[0047] However, the existing detection method cannot determine the appropriate refraction angle for different specifications of round bars, and the verification sensitivity is random. The scanning sensitivity of different shear wave refraction angles for surface defects and near-surface defects of round bars is significantly different, and the existing detection method cannot obtain good scanning signals for surface groove and near-surface transverse hole at the same time. The existing detection method is difficult, time-consuming, and has low success rate for one-time verification, and sometimes needs to be repeated several times for verification, which seriously affects the work efficiency.

[0048] Based on the above problems, the embodiment of the present application provides a rotating ultrasonic detection method for defects in the near-surface area of a round bar, which can obtain good scanning signals for surface grooves and near-surface transverse holes at the same time when detecting and verifying the near-surface area of the round bar, ensuring the reliability of the detection, and providing a unified basis for quickly and accurately adjusting the probe inclination angle. It has the characteristics of scientific and reasonable, standard and normative, accurate and efficient, safe, easy to learn and use, and easy to promote.

[0049] In detail, please refer to Figures 1 to 4 The rotating ultrasonic detection method for defects in the near-surface area of a round bar comprises the following steps:

[0050] Step S100, selecting a round bar with the same specification as the to-be-detected bar as a sample bar 100, and setting a surface groove 110 and a near-surface transverse hole 120 on the sample bar 100;

[0051] Step S200, emitting ultrasonic waves from the ultrasonic probe 200 to the sample bar 100 to obtain ultrasonic signals corresponding to the surface groove 110 and the near-surface transverse hole 120;

[0052] Step S300, adjusting the parameters of the ultrasonic probe 200 according to the ultrasonic signals, and setting the corresponding parameters under the condition that the amplitudes of the ultrasonic signals corresponding to the surface groove 110 and the near-surface transverse hole 120 are consistent;

[0053] Step S400, making the ultrasonic probe 200 scan the to-be-detected bar with the set parameters.

[0054] In the embodiment, the signal of the ultrasonic probe 200 is adjusted by the corresponding ultrasonic signals of the surface groove 110 and the near-surface transverse hole 120, so that the setting parameters of the ultrasonic probe 200 corresponding to the amplitude consistency of the ultrasonic signals of the surface groove 110 and the near-surface transverse hole 120 are obtained, that is, the setting parameters of the ultrasonic probe 200 can be set according to the specifications of the sample rod 100, so that good scanning signals of the surface groove 110 and the near-surface transverse hole 120 are obtained at the same time when the sample rod 100 and the near-surface area of the sample rod are detected and verified, the detection reliability is improved, the operation is simple, and thus the work efficiency is improved.

[0055] Further, the step S100 further includes:

[0056] The step S110 is to set the surface groove 110 on the outer side wall of the sample rod 100.

[0057] In the embodiment, the 0.3mm surface groove 110 can be machined on the surface of the sample rod 100 as an artificial reference defect.

[0058] Of course, other sizes of the surface groove 110 can be machined on other specifications of the sample rod 100, which are not limited here.

[0059] The step S120 is to determine the orientation of the near-surface transverse hole 120 according to the position of the surface groove 110.

[0060] In the embodiment, the orientation of the near-surface transverse hole 120 can be determined after the position of the surface groove 110 is determined; the size of the near-surface transverse hole 120 is φ0.5*12.7mm, and it can be understood that the size of the near-surface transverse hole 120 can also be other sizes in other embodiments, which are not limited here.

[0061] Further, the step S120 further includes:

[0062] The step S121 is to emit ultrasonic waves to the sample rod 100 by the ultrasonic probe.

[0063] The step S122 is to adjust the ultrasonic probe 200 so that the refraction angle of the ultrasonic waves in the sample rod 100 is a first preset angle.

[0064] It should be noted that the first preset angle is the included angle between the refraction path of the ultrasonic waves in the sample rod 100 and the line connecting the refraction point and the center of the sample rod 100, and the first preset angle is 40°-50°.

[0065] Alternatively, the first preset angle can be 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, and 50°, and of course, the first preset angle can also be other degrees in the interval of 40°-50° in other embodiments, which are not limited here.

[0066] Step S123, the maximum scanning depth of the transverse wave main sound axis corresponding to the ultrasonic wave is obtained (as shown by H1 in the figure) ;

[0067] In the embodiment, the refracted sound wave main sound axis 210 of the ultrasonic wave in the sample rod 100 is obtained, and the maximum scanning depth of the refracted sound wave main sound axis 210 in the sample rod 100, that is, the maximum vertical distance between the refracted sound wave main sound axis 210 and the outer wall of the sample rod 100 (as shown by H2 in the figure) is obtained.

[0068] Step S124, a circular curve at the midpoint corresponding to the maximum scanning depth is made with the center of the cross section of the sample rod 100 (as shown by A in the figure) ;

[0069] In the embodiment, the midpoint corresponding to the maximum scanning depth can determine the surface distance of the near-surface transverse hole 120.

[0070] Step S124, the orientation of the near-surface transverse hole 120 is determined by the intersection of the circular curve and the surface groove 110 in the radial direction.

[0071] In the embodiment, after the depth of the near-surface transverse hole 120 is determined, the orientation of the near-surface transverse hole 120 is determined by the intersection of the circular curve and the surface groove 110 in the radial direction.

[0072] It should be noted that when the near-surface transverse hole 120 is set, the following steps are also included:

[0073] The cutting part 130 is selected on the sample rod 100, and the cutting part 130 and the surface groove 110 have a preset interval in the axial direction of the sample rod 100;

[0074] The sample rod 100 is cut into two pieces along the cutting part 130, and the near-surface transverse hole 120 is opened in the cross section of one of the pieces which is not provided with the surface groove 110;

[0075] The two sample rods 100 are joined.

[0076] It should be noted that the parameters of the ultrasonic probe 200 can include sensitivity and inclination angle; of course, the parameters of the ultrasonic probe 200 can also include other parameters, which are not limited here.

[0077] Further, before step S200, it also includes:

[0078] The coupling water 300 is filled between the ultrasonic probe 200 and the sample rod 100; it can be understood that the coupling water 300 is uniformly arranged outside the sample rod 100, so that the ultrasonic wave emitted by the ultrasonic probe 200 enters the sample rod 100 through the coupling water 300.

[0079] Further, step S300 further includes:

[0080] Step S310, adjust the inclination and sensitivity of the ultrasonic probe 200, and set the sensitivity at this time as the initial sensitivity in the case that the ultrasonic signal 410 of the surface groove shows the maximum amplitude;

[0081] In the embodiment, after the ultrasonic probe 200 irradiates the sample rod 100, the inclination and sensitivity of the ultrasonic probe 200 can be adjusted until the maximum amplitude of the ultrasonic signal 410 of the surface groove is close to full screen, so that the signal is more intuitive, and subsequent further adjustment of the parameters of the ultrasonic probe 200 is facilitated.

[0082] Step S320, make the ultrasonic probe 200 irradiate at the initial sensitivity, and acquire the ultrasonic signal 410 of the surface groove and the ultrasonic signal 430 of the interface between the coupling water and the sample rod;

[0083] In the embodiment, after the maximum amplitude of the ultrasonic signal 410 of the surface groove is close to full screen, the irradiation is continued at the initial sensitivity, and the ultrasonic signal 410 of the surface groove and the ultrasonic signal 430 of the interface between the coupling water and the sample rod are acquired.

[0084] Step S330, adjust the ultrasonic probe 200 according to the ultrasonic signal 410 of the surface groove and the ultrasonic signal 430 of the interface between the coupling water and the sample rod, so that the refraction angle of the ultrasonic wave in the sample rod reaches a second preset angle (such as the angle B shown in the figure);

[0085] In the embodiment, the refraction angle can be calculated from the ultrasonic signal 410 of the surface groove and the ultrasonic signal 430 of the interface between the coupling water and the sample rod, and the refraction inclination is adjusted to the second preset angle.

[0086] In detail, the second preset angle is the included angle between the refraction path of the ultrasonic wave in the sample rod 100 and the line connecting the refraction point and the center of the sample rod 100, and the second preset angle is 40°-50°.

[0087] Alternatively, the second preset angle can be 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, and 50°. Of course, in other embodiments, the second preset angle can also be other degrees in the interval of 40°-50°, which is not limited here.

[0088] Step S340, adjust the sensitivity of the ultrasonic probe 200 in the case that the ultrasonic wave irradiates at the second preset angle, and set the sensitivity at this time as the set sensitivity in the case that the amplitudes of the ultrasonic signals 420 of the surface groove 110 and the near-surface transverse hole are consistent.

[0089] In the embodiment, after the inclination of the ultrasonic probe 200 is determined, the sensitivity is further adjusted so that the amplitudes of the ultrasonic signals 420 of the surface groove 110 and the near-surface transverse hole reach a predetermined amplitude, and the sensitivity at this time is set as the preset sensitivity; at this time, the sensitivity and the inclination are kept unchanged, and the sample bar is scanned by the overbar calibration, so that the near-surface transverse hole 120 scanning signals and the surface groove 110 scanning signals of the sample bar 100 with good consistency can be obtained.

[0090] Further, the step S400 further comprises:

[0091] The ultrasonic probe 200 irradiates and scans the sample bar at the second preset angle and the set sensitivity.

[0092] In the embodiment, the near-surface transverse hole 120 scanning signals and the surface groove 110 scanning signals of the sample bar with good consistency can be obtained at the second preset angle and the set sensitivity.

[0093] In summary, the embodiment of the present application provides a method for detecting defects in the near-surface region of a rotating ultrasonic detection round bar, which is characterized by accurately positioning the orientation of the surface groove and the near-surface transverse hole 120 of the round bar and the refraction angle of the transverse wave. In particular, the depth of the near-surface transverse hole 120 is directly proportional to the size of the round bar, and the present application proposes a specific depth calculation method rather than setting a fixed depth range suitable for all round bar sizes. This design not only embodies innovation, but also ensures flexibility and applicability. In terms of reliability, the present application further discloses the proportional relationship between the depth of the near-surface transverse hole 120 and the depth of the scanning area where it is located, which enables these depth points to better represent the entire depth range during transverse wave scanning, thereby ensuring the reliability and consistency of the detection results. Through this method, the stability and credibility of the detection process can be effectively improved. The present application has significantly improved in standardization and accuracy, and it provides a universal calibration method that can be used for near-surface detection of round bars of any size using a unified refraction angle calibration standard. This not only eliminates randomness and uncertainty in the calibration process, but also ensures the consistency of the calibration effect and the reliability of the detection results. In terms of operational simplicity, the present application optimizes the selection of the refraction angle, so that the detection of the surface groove 110 and the near-surface transverse hole 120 can both achieve good results. This means that the refraction angle can be determined only by the calibration of the surface groove 110, without the need for additional operations to adjust the refraction angle for the near-surface transverse hole 120, greatly simplifying the operation process and significantly saving time and resources.

[0094] Finally, in terms of promotion and application value, the application not only defines representative defect specifications, positions and refraction angles, but also provides a systematic methodology, allowing other different specifications of defects to be checked by referring to similar strategies to determine the proportional relationship between the depth of the near-surface transverse hole 120 and the bar specification and the accurate refraction angle. This innovative method not only enhances the universal applicability of the detection technology, but also provides strong support for the standardization and efficiency improvement of the industry.

[0095] The above merely provides a specific implementation of the application, but the protection scope of the application is not limited thereto, and any changes or replacements easily thought of by those skilled in the art within the technical range disclosed by the application should be encompassed within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method of rotating ultrasonic testing of a near-surface region of a round bar for defects, characterized in that, The application relates to a method for detecting a rod, and comprises the following steps: a sample rod with the same specification as the rod to be detected is selected, and a surface groove and a near-surface transverse hole are arranged on the sample rod; ultrasonic waves are emitted from an ultrasonic probe to the sample rod, and ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are acquired; parameters of the ultrasonic probe are adjusted according to the ultrasonic signals, and the parameters corresponding to the case that the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent are set; the ultrasonic probe is used to scan the rod to be detected with the set parameters; the method further comprises the following steps: the angle and the sensitivity of the ultrasonic probe are adjusted, and the sensitivity at the moment when the ultrasonic signal of the surface groove shows the maximum amplitude is set as the initial sensitivity; the ultrasonic probe is used to irradiate with the initial sensitivity, and ultrasonic signals of the surface groove and the interface between the coupling water and the sample rod are acquired; the ultrasonic probe is adjusted according to the ultrasonic signals of the surface groove and the interface between the coupling water and the sample rod, so that the refraction angle of the ultrasonic waves in the sample rod reaches a second preset angle; the method further comprises the following steps: in the case that the ultrasonic waves are irradiated with the second preset angle, the sensitivity of the ultrasonic probe is adjusted, so that the sensitivity at the moment when the amplitudes of the ultrasonic signals of the surface groove and the near-surface transverse hole are consistent is set as the set sensitivity.

2. The method of claim 1, wherein the method further comprises: the method further comprises the following steps: a surface groove is arranged on the surface of the sample rod; the position of the near-surface transverse hole is determined according to the position of the surface groove.

3. The method of claim 2, wherein the method further comprises: the method further comprises the following steps: ultrasonic waves are emitted from an ultrasonic probe to the sample rod; the ultrasonic probe is adjusted so that the refraction angle of the ultrasonic waves in the sample rod is a first preset angle; the maximum scanning depth of the transverse wave main sound axis corresponding to the ultrasonic waves is acquired; a circumferential line is drawn with the center of the cross section of the sample rod as the center and passing through the midpoint corresponding to the maximum scanning depth; the position of the near-surface transverse hole is determined according to the intersection of the circumferential line and the surface groove in the radial direction.

4. The method of claim 3, wherein the method further comprises: the first preset angle is the included angle between the refraction route of the ultrasonic waves in the sample rod and the line connecting the refraction point and the center of the sample rod, and the first preset angle is 40-50 degrees.

5. The method of claim 1 wherein, the parameters of the ultrasonic probe include the sensitivity and the angle.

6. The method of claim 1 wherein, the second preset angle is the included angle between the refraction route of the ultrasonic waves in the sample rod and the line connecting the refraction point and the center of the sample rod, and the second preset angle is 40-50 degrees.

7. The method of claim 6 wherein the step of rotating the ultrasonic probe is performed by rotating the ultrasonic probe about the longitudinal axis of the probe. the method further comprises the following steps: the ultrasonic probe is used to irradiate and scan the rod to be detected with the second preset angle and the set sensitivity.

8. The method of claim 1 wherein the method further comprises: Before the step of emitting ultrasonic waves from the ultrasonic probe to the sample rod, further comprising: Filling coupling water between the ultrasonic probe and the sample rod.

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