Method for detecting defects of near-surface area of round rod by rotary ultrasonic detection

Abstract

The invention provides a rotary ultrasonic detection method for defects of a near-surface area of a round rod, and relates to the technical field of material detection. The method comprises the following steps: selecting a round rod with the same specification as a to-be-detected rod as a sample rod, and forming a surface groove and a near-surface transverse hole in the sample rod; the ultrasonic probe transmits ultrasonic waves to the sample rod, and ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are obtained; parameters of the ultrasonic probe are adjusted according to the ultrasonic signals, and corresponding setting parameters are set under the condition that the amplitudes of the ultrasonic signals corresponding to the surface grooves and the near-surface transverse holes are consistent; the ultrasonic probe scans the to-be-detected rod according to set parameters; the set parameters of the ultrasonic probe corresponding to the consistent amplitude of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are obtained, it is ensured that good scanning signals are obtained for the surface groove damage and the near-surface transverse hole at the same time when the sample rod near-meter area is detected and verified, the detection reliability is improved, operation is easy, the success rate is high, and therefore the operation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material detection, and in particular to a method for detecting defects in a near-surface area of ​​a round rod by using rotary ultrasonic detection. Background Art

[0002] Pulse reflection ultrasonic testing is an important tool for evaluating the internal quality of dense materials such as metal materials. This technology transmits ultrasonic waves through the probe and receives ultrasonic signals reflected by defects in the workpiece, and then the equipment generates an intuitive display signal. Based on parameters such as the position and amplitude of the signal, the internal condition of the workpiece can be accurately judged.

[0003] However, the existing detection methods usually cannot determine the appropriate refraction angle for round rods of different specifications, the verification sensitivity is random, and the scanning sensitivity of different shear wave refraction angles to the surface defects and near-surface defects of the round rods is significantly different. It is impossible to obtain good scanning signals for both surface grooves and subcutaneous near-surface transverse holes at the same time. In addition, the existing detection methods are difficult and time-consuming, and the success rate of one-time verification is low, which affects the work efficiency. Summary of the invention

[0004] The present invention provides a method for detecting defects in the near-surface area of ​​a round rod by rotary ultrasonic detection. The method can simultaneously obtain good scanning signals for surface groove defects and near-surface transverse holes when detecting and verifying the near-surface areas of a sample rod and a rod to be detected, thereby improving detection reliability, simplifying operation, and improving operating efficiency.

[0005] The embodiments of the present invention can be implemented as follows:

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

[0007] Select a round rod with the same specifications as the rod to be tested as a sample rod, and set a surface groove and a near-surface transverse hole on the sample rod;

[0008] The ultrasonic probe emits ultrasonic waves to the sample rod to obtain ultrasonic signals corresponding to the surface grooves and the near-surface transverse holes;

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

[0010] The ultrasonic probe is used to scan the rod to be inspected according to the set parameters.

[0011] In an optional embodiment, the provision of surface grooves and near-surface transverse holes on the sample rod further comprises:

[0012] Arranging a surface groove on the surface of the sample rod;

[0013] The position of the near-surface transverse hole is determined according to the position of the surface groove.

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

[0015] The ultrasonic probe emits ultrasonic waves toward the sample rod;

[0016] Adjusting the ultrasonic probe so that the refraction angle of the ultrasonic wave on the sample rod is a first preset angle;

[0017] Obtaining the maximum scanning depth of the main acoustic axis of the shear wave corresponding to the ultrasonic wave;

[0018] A circular 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] The orientation of the near-surface transverse hole is determined by 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 angle between the refraction line of the ultrasonic wave 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° to 50°.

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

[0022] In an optional embodiment, the step of adjusting the parameters of the ultrasonic probe according to the ultrasonic signal and setting the corresponding setting parameters when the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent also includes:

[0023] Adjusting the inclination angle and sensitivity of the ultrasonic probe, and setting the sensitivity at this time as the initial sensitivity when the ultrasonic signal of the surface groove shows the maximum amplitude;

[0024] Allowing the ultrasonic probe to irradiate at the initial sensitivity to obtain ultrasonic signals of the surface groove and ultrasonic signals of the interface between the coupled water and the sample rod;

[0025] According to the ultrasonic signal of the surface groove and the ultrasonic signal of the interface between the coupling water and the sample rod, the ultrasonic probe is adjusted so that the refraction angle of the ultrasonic wave 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 signal and setting the corresponding setting parameters when the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent also includes:

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

[0028] In an optional embodiment, the second preset angle is the angle between the refraction line of the ultrasonic wave 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° to 50°.

[0029] In an optional implementation, the step of causing the ultrasonic probe to scan the rod to be inspected with the set parameters further includes:

[0030] The ultrasonic probe is made to irradiate and scan the rod to be inspected at the second preset angle and the set sensitivity.

[0031] In an optional embodiment, before the step of transmitting ultrasonic waves to the sample rod by the ultrasonic probe, the method further includes:

[0032] The space between the ultrasonic probe and the sample rod is filled with coupling water.

[0033] The beneficial effects of the method for rotating ultrasonically detecting defects in the near-surface area of ​​a round rod provided by an embodiment of the present invention include: adjusting the parameter settings of the ultrasonic probe through the ultrasonic signals corresponding to the surface grooves and the near-surface transverse holes, so as to obtain setting parameters of the ultrasonic probe corresponding to the amplitudes of the ultrasonic signals corresponding to the surface grooves and the near-surface transverse holes, that is, being able to set reasonable setting parameters of the ultrasonic probe according to the specifications of the sample rod, ensuring that good scanning signals are obtained for both the surface groove defects and the near-surface transverse holes during the near-surface area detection and verification of the sample rod and the rod to be inspected, thereby improving detection reliability, simplifying operation, and thus improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A schematic flow chart of a method for detecting defects near the surface of a round bar using rotary ultrasonic technology provided in an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a sample rod structure provided by an embodiment of the present invention;

[0037] Figure 3 A cross-sectional view of a sample rod provided by an embodiment of the present invention;

[0038] Figure 4 The embodiment of the present invention provides Figure 3 Enlarged view of the structure in the middle.

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

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0044] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0045] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0046] Pulse reflection ultrasonic testing is an important tool for evaluating the internal quality of dense materials such as metal materials. This technology transmits ultrasonic waves through the probe and receives ultrasonic signals reflected by defects in the workpiece, and then the equipment generates an intuitive display signal. Based on 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 methods usually cannot determine the appropriate refraction angle for round bars of different specifications, the verification sensitivity is random, and the scanning sensitivity of different shear wave refraction angles to the surface defects and near-surface defects of the round bar is significantly different. It is impossible to obtain good scanning signals for both surface grooves and near-surface transverse holes at the same time. In addition, the existing detection methods are difficult and time-consuming, with a low success rate of one-time verification. Sometimes repeated verification operations are required, which seriously affects work efficiency.

[0048] Based on the above problems, the embodiment of the present invention provides a method for detecting defects in the near-surface area of ​​a round bar by rotary ultrasonic detection, which can simultaneously obtain good scanning signals for surface grooves and near-surface transverse holes during the detection and verification of the near-surface area of ​​the round bar, ensure the reliability of the detection, and provide a unified basis for quickly and accurately adjusting the inclination angle of the probe. 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] For details, see Figures 1 to 4 The method for detecting defects near the surface of a round bar by rotating ultrasonic wave comprises the following steps:

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

[0051] Step S200, the ultrasonic probe 200 transmits ultrasonic waves to the sample rod 100 to obtain ultrasonic signals corresponding to the surface grooves 110 and the near-surface transverse holes 120;

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

[0053] Step S400 , enabling the ultrasonic probe 200 to scan the rod to be inspected with set parameters.

[0054] In this embodiment, the signal of the ultrasonic probe 200 is adjusted by the ultrasonic signals corresponding to the surface groove 110 and the near-surface transverse hole 120, so as to obtain setting parameters of the ultrasonic probe 200 corresponding to the amplitudes of the ultrasonic signals corresponding to the surface groove 110 and the near-surface transverse hole 120. That is, reasonable setting parameters of the ultrasonic probe 200 can be set according to the specifications of the sample rod 100, ensuring that good scanning signals are obtained for the surface groove flaws 110 and the near-surface transverse holes 120 at the same time when the near-surface areas of the sample rod 100 and the rod to be inspected are inspected and verified, thereby improving detection reliability, simplifying operation, and thus improving work efficiency.

[0055] Furthermore, step S100 also includes:

[0056] Step S110, providing a surface groove 110 on the outer side wall of the sample rod 100;

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

[0058] Of course, surface grooves 110 of other sizes may also be processed for sample rods 100 of other specifications, which are not specifically limited here.

[0059] In step S120 , the position of the near-surface transverse hole 120 is determined according to the position of the surface groove 110 .

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

[0061] Furthermore, step S120 further includes:

[0062] Step S121, emitting ultrasonic waves to the sample rod 100 by an ultrasonic probe;

[0063] Step S122, adjusting the ultrasonic probe 200 so that the refraction angle of the ultrasonic wave in the sample rod 100 is a first preset angle;

[0064] It should be noted that the first preset angle is the angle between the refraction line 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 first preset angle is 40° to 50°.

[0065] Optionally, the first preset angle can be 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49° and 50°. Of course, in other embodiments, the first preset angle can also be other degrees in the range of 40° to 50°, which is not specifically limited here.

[0066] Step S123, obtaining the maximum scanning depth of the main acoustic axis of the shear wave corresponding to the ultrasonic wave (as shown by H1 in the figure);

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

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

[0069] In this embodiment, the depth of the near-surface transverse hole 120 from the surface can be determined at the midpoint corresponding to the maximum scanning depth.

[0070] Step S124 , determining the position of the near-surface transverse hole 120 by the intersection of the circumferential line and the surface groove 110 in the radial direction.

[0071] In this 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 circumferential line and the surface groove 110 in the radial direction.

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

[0073] A cutting portion 130 is selected on the sample rod 100, and a preset distance is formed between the cutting portion 130 and the surface groove 110 in the axial direction of the sample rod 100;

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

[0075] The two sample bars 100 are joined.

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

[0077] Furthermore, before step S200, the method further 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 evenly 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] Furthermore, step S300 further includes:

[0080] Step S310, adjusting the inclination angle and sensitivity of the ultrasonic probe 200, and setting the sensitivity at this time as the initial sensitivity when the ultrasonic signal 410 of the surface groove shows the maximum amplitude;

[0081] In this embodiment, after the ultrasonic probe 200 irradiates the sample rod 100, the inclination angle 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 the full screen, thereby making the signal more intuitive and facilitating subsequent adjustment of the parameters of the ultrasonic probe 200.

[0082] Step S320, making the ultrasonic probe 200 irradiate at an initial sensitivity to obtain an ultrasonic signal 410 of the surface groove and an ultrasonic signal 430 of the interface between the coupled water and the sample rod;

[0083] In this embodiment, after the maximum amplitude of the ultrasonic signal 410 of the surface groove approaches the full screen, the irradiation is continued with the initial sensitivity, and the ultrasonic signal 410 of the surface groove and the ultrasonic signal 430 of the interface between the coupled water and the sample rod are obtained.

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

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

[0086] In detail, the second preset angle is the angle between the refraction line 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° to 50°.

[0087] Optionally, 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 range of 40° to 50°, which is not specifically limited here.

[0088] Step S340, when the ultrasonic wave is irradiated at a second preset angle, the sensitivity of the ultrasonic probe 200 is adjusted, and when the amplitudes of the ultrasonic signals 420 of the surface groove 110 and the near-surface transverse hole are consistent, the sensitivity at this time is set as the set sensitivity.

[0089] In this embodiment, after the inclination angle of the ultrasonic probe 200 is determined, the sensitivity is further adjusted so that the amplitudes of the ultrasonic signals 420 of the surface grooves 110 and the near-surface transverse holes reach a predetermined amplitude, and the sensitivity at this time is set to the preset sensitivity; at this time, the sensitivity and inclination angle are kept unchanged, and the rod to be inspected is scanned through the rod calibration to obtain the near-surface transverse hole 120 scanning signal and the surface groove 110 scanning signal with good consistency of the sample rod 100.

[0090] Furthermore, step S400 further includes:

[0091] The ultrasonic probe 200 is made to irradiate and scan the rod to be inspected at a second preset angle and set sensitivity.

[0092] In this embodiment, with the second preset angle and the set sensitivity, a scanning signal of the near-surface transverse hole 120 and a scanning signal of the surface groove 110 of the rod to be inspected with good consistency can be obtained.

[0093] In summary, the embodiment of the present invention provides a method for detecting defects in the near-surface area of ​​a round bar by rotating ultrasonic detection, the core of which is to accurately locate the grooves on the surface of the round bar, the orientation of the near-surface transverse hole 120, and the refraction angle of the shear wave. In particular, there is a direct proportional relationship between the depth of the near-surface transverse hole 120 and the specifications of the round bar. The present invention proposes a targeted depth calculation method instead of setting a fixed depth range applicable to all round bar specifications. This design not only reflects innovation, but also ensures flexibility and applicability. In terms of reliability, the present invention further reveals the proportional relationship between the depth of the near-surface transverse hole 120 and the depth of the scanning area in which it is located, which enables these depth points to better represent the entire depth range during the shear wave scanning process, 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 invention has made significant improvements in standardization and accuracy. It provides a universal verification method. Regardless of the specifications of the round bar, a unified refraction angle verification standard can be used for near-surface detection. This not only eliminates the randomness and uncertainty in the verification process, but also ensures the consistency of the verification effect and the reliability of the detection results. In terms of ease of operation, the present invention optimizes the selection of the refraction angle so that good results can be obtained in the detection of both the surface groove 110 and the near-surface transverse hole 120. This means that the refraction angle only needs to be determined by checking the surface groove 110, and there is no need to perform multiple additional operations on the near-surface transverse hole 120 to adjust the refraction angle, which greatly simplifies the operation process and significantly saves working time and resources.

[0094] Finally, in terms of promotion and application value, the present invention not only defines representative defect specifications, positions and refraction angles, but also provides a systematic methodology that allows other defects of different specifications to refer to similar strategies when checking defects to determine the proportional relationship between the near-surface transverse hole 120 depth and the round bar specifications and the precise refraction angle. This innovative method not only enhances the universal applicability of the detection technology, but also provides strong support for industry standardization and efficiency improvement.

[0095] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for detecting defects near the surface of a round bar by rotary ultrasonic detection, characterized in that: include: Select a round rod with the same specifications as the rod to be tested as a sample rod, and set a surface groove and a near-surface transverse hole on the sample rod; The ultrasonic probe emits ultrasonic waves to the sample rod to obtain ultrasonic signals corresponding to the surface grooves and the near-surface transverse holes; Adjusting the parameters of the ultrasonic probe according to the ultrasonic signal, and setting the corresponding setting parameters when the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent; The ultrasonic probe is used to scan the rod to be inspected according to the set parameters.

2. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 1, characterized in that: The provision of the surface groove and the near-surface transverse hole on the sample rod also includes: Arranging a surface groove 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 for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 2, characterized in that: Determining the position of the near-surface transverse hole according to the position of the surface groove also includes: The ultrasonic probe emits ultrasonic waves toward the sample rod; Adjusting the ultrasonic probe so that the refraction angle of the ultrasonic wave on the sample rod is a first preset angle; Obtaining the maximum scanning depth of the main acoustic axis of the shear wave corresponding to the ultrasonic wave; A circular 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; The orientation of the near-surface transverse hole is determined by the intersection of the circumferential line and the surface groove in the radial direction.

4. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 3 is characterized in that: The first preset angle is the angle between the refraction line of the ultrasonic wave in the sample rod and the line connecting the refraction point and the center of the sample rod. The first preset angle is 40° to 50°.

5. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 1, characterized in that: The parameters of the ultrasonic probe include sensitivity and inclination.

6. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 1, characterized in that: The step of adjusting the parameters of the ultrasonic probe according to the ultrasonic signal and setting the corresponding setting parameters when the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent also includes: Adjusting the inclination angle and sensitivity of the ultrasonic probe, and setting the sensitivity at this time as the initial sensitivity when the ultrasonic signal of the surface groove shows the maximum amplitude; Allowing the ultrasonic probe to irradiate at the initial sensitivity to obtain ultrasonic signals of the surface groove and ultrasonic signals of the interface between the coupled water and the sample rod; According to the ultrasonic signal of the surface groove and the ultrasonic signal of the interface between the coupling water and the sample rod, the ultrasonic probe is adjusted so that the refraction angle of the ultrasonic wave in the sample rod reaches a second preset angle.

7. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 6, characterized in that: The step of adjusting the parameters of the ultrasonic probe according to the ultrasonic signal and setting the corresponding setting parameters when the amplitudes of the ultrasonic signals corresponding to the surface groove and the near-surface transverse hole are consistent also includes: When the ultrasonic wave is irradiated at the second preset angle, the sensitivity of the ultrasonic probe is adjusted so that the sensitivity at this time is set as the set sensitivity when the amplitudes of the ultrasonic signals of the surface groove and the near-surface transverse hole are consistent.

8. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 6, characterized in that: The second preset angle is the angle between the refraction line of the ultrasonic wave 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° to 50°.

9. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 7, characterized in that: The step of causing the ultrasonic probe to scan the rod to be inspected with the set parameters further comprises: The ultrasonic probe is made to irradiate and scan the rod to be inspected at the second preset angle and the set sensitivity.

10. The method for detecting defects near the surface of a round bar by rotary ultrasonic detection according to claim 1, characterized in that: Before the step of transmitting ultrasonic waves to the sample rod by the ultrasonic probe, the method further comprises: The space between the ultrasonic probe and the sample rod is filled with coupling water.

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