A single-side ultrasonic oblique incidence full-coverage detection method for crack defects of a rotary body part

Abstract

The application discloses a kind of rotary body parts crack defect single-side ultrasonic oblique incidence full coverage detection method, belong to the field of measurement and control, the implementation steps of this method include: the crack occurrence area of the step root of rotary body parts is divided into two adjacent regions A and region B;Ultrasonic wave is obliquely incident from the end face of one end of rotary body parts, so that the refracted transverse wave only propagates between the two end faces of rotary body parts, and the crack in region A is detected;Ultrasonic wave is obliquely incident from the same end of rotary body parts, so that the refracted transverse wave propagates using the step, and the crack in region B is detected.This method ingeniously utilizes the structure of the boss itself, so that only ultrasonic oblique incidence from one end of rotary body parts can detect the cracks of all angles at the step root of both ends of rotary body parts, improve the detection efficiency, and reduce the labor intensity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of measurement and control technology, and particularly relates to a single-side ultrasonic oblique incidence full coverage detection method for crack defects of a rotary part. BACKGROUND

[0002] Rotary parts containing cross-section mutation sites such as wheels are widely used in power and transmission devices, such as wheel shafts, wheel discs and high-speed rail wheels of power devices such as aerospace, aviation and ship engines. The surface of the rotary part usually has a step structure for guiding and positioning. These step cross-section mutation sites are prone to stress concentration during the manufacturing process, and cracks are generated at the root of the step within an angle range of 0°-90°, which further causes fatigue crack propagation during service, leading to failure of the component and affecting the performance, reliability and safety of the overall device.

[0003] Ultrasonic oblique incidence detection is an effective crack detection method, which can determine whether there is a defect inside the detected component according to the presence or absence of a defect echo. The traditional oblique incidence method is to make ultrasonic waves obliquely incident from the end face of one end of the rotary part, so that the refracted transverse waves only propagate between the two end faces of the rotary part, and the crack is detected by using the end angle reflection of the part surface and the crack. However, the upper and lower ends of the rotary part both have step structures for guiding and positioning. Without flipping the upper and lower end faces, if only the traditional ultrasonic oblique incidence method is used for detection, the cracks located in the specific angle range of the step root cannot form end angle reflection, and it is also difficult to achieve single-side oblique incidence full coverage detection of all step root cracks.

[0004] In order to improve the detection efficiency and reduce the labor intensity, especially for large rotary parts, it is often desired to complete the full coverage detection of the crack occurrence angle range of 0°-90° at the step roots of both ends of the rotary part in one clamping (single station) without flipping the upper and lower end faces. SUMMARY

[0005] Therefore, the present application provides a single-side ultrasonic oblique incidence full coverage detection method for crack defects of a rotary part, which can fully utilize the structure of the step itself to complete the full coverage detection of the cracks at the step roots of both ends of the rotary part by making ultrasonic waves obliquely incident from one end of the rotary part without flipping the upper and lower end faces of the rotary part.

[0006] Advantages:

[0007] (1) The detection method of the present application makes the ultrasonic wave obliquely incident from the end face of one end of the rotary part, makes the refracted transverse wave only propagate between the two end faces of the rotary part, and detects the cracks in one angle range of the step root; makes the ultrasonic wave obliquely incident from the same end of the rotary part, makes the refracted transverse wave fully utilize the structure of the step to propagate, and detects the cracks in another angle range of the step root. This method ingeniously utilizes the structure of the step, so that the cracks in all angles of the step roots at both ends of the rotary part can be detected only by obliquely incident ultrasonic wave from one end of the rotary part, the problem of needing to turn over the end faces of the rotary part when detecting the cracks in the step roots at the upper and lower ends of the rotary part is solved, the detection efficiency is improved, and the labor intensity is reduced.

[0008] (2) The detection method of the present application can flexibly design the specific ultrasonic wave propagation route according to the specific step distribution form of the rotary part, for example, when detecting the cracks in the area of the rotary part which is located at the ultrasonic wave incident end and cannot be detected by the traditional detection method without turning over the rotary part, the ultrasonic wave is obliquely incident from the side face of the step of the rotary part; when detecting the cracks in the area of the other end of the rotary part which is opposite to the ultrasonic wave incident end and cannot be detected by the traditional detection method without turning over the rotary part, the ultrasonic wave can be obliquely incident from the end face (instead of the side face of the step) of the rotary part, which makes the present method very suitable for detecting the step cracks of the rotary part.

[0009] (3) Before detecting the cracks in the step of the actual rotary part, the detection sensitivity is calibrated by comparing the test sample, so that the present method can cover all possible distribution angles of the natural cracks when detecting the natural crack defects in the step root of the actual rotary part, and the method is rigorous and reliable.

[0010] (4) The detection method of the present application can detect the crack defects in all areas of the step root of the rotary part by ultrasonic C scanning, and can not only detect the position of the crack but also intuitively display the structural form of the crack, which is beneficial to the improvement of the manufacturing process of the rotary part and the failure analysis of the rotary part.

[0011] (5) The detection method of the present application can detect the cracks in the step root of the rotary part by means of an industrial robot, further improving the detection efficiency, reducing the labor intensity, and also increasing the reliability of the detection results.

[0012] (6) The scanning scheme of the ultrasonic C scanning used in the present application is spiral scanning, the movement speed of the manipulator is stable and reliable, the movement of the turntable is uniform and continuous, and the movement of the manipulator and the turntable is independent of each other, so that the crack defect signal can be easily collected, the operability of the detection method is enhanced, and the accuracy of the detection results is improved. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the division of the step root region of the rotating body part in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the detection scheme for the root crack of the step in the rotating body part in the embodiment of the present invention, wherein (a) is a schematic diagram of the detection scheme for the root crack of the step on the upper end face; (b) is a schematic diagram of the detection scheme for the root crack defect of the step on the lower end face; and (c) is an enlarged schematic diagram of the crack detection scheme in areas 6 and 8 in Figure (b).

[0015] Figure 3 (a) is a schematic diagram of a comparative sample of a rotating body part in an embodiment of the present invention, and (b) is a schematic diagram of the distribution of prefabricated defects in the comparative sample.

[0016] Figure 4 (a) is Figure 3 A schematic diagram of the prefabricated defect detection scheme at the root of the upper and middle end face steps, (b) is... Figure 3 A schematic diagram of the prefabricated defect detection scheme at the root of the lower end face step;

[0017] Figure 5 for Figure 3 The diagrams show the ultrasonic A-scan signals of prefabricated defects in the comparative specimens. (a) shows the ultrasonic A-scan signal of the 90° prefabricated defect at point ① in region 1 under the detection scheme; (b) shows the ultrasonic A-scan signal of the 45° prefabricated defect at point ② in region 1 under the detection scheme; (c) shows the ultrasonic A-scan signal of the 45° prefabricated defect at point ② in region 2 under the detection scheme; (d) shows the ultrasonic A-scan signal of the 0° prefabricated defect at point ③ in region 2 under the detection scheme; (e) shows the ultrasonic A-scan signal of the 90° prefabricated defect at point ④ in region 3 under the detection scheme; and (f) shows the ultrasonic A-scan signal of the 0° prefabricated defect at point ⑤ in region 4 under the detection scheme. (g) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 90° prefabricated defect at position ⑥ in region 5; (h) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 45° prefabricated defect at position ⑦ in region 5; (i) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 45° prefabricated defect at position ⑦ in region 6; (j) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 0° prefabricated defect at position ⑧ in region 6; (k) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 90° prefabricated defect at position ⑨ in region 7; (l) is a schematic diagram of the ultrasonic A-scan signal under the detection scheme of the 0° prefabricated defect at position ⑩ in region 8.

[0018] Figure 6 For Figure 3 Schematic diagram of ultrasonic C-scan signals of the contrast sample preformed defects, wherein (a) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 1 and serial number 2 under detection scheme of region 1; (b) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 2 and serial number 3 under detection scheme of region 2; (c) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 4 under detection scheme of region 3; (d) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 5 under detection scheme of region 4; (e) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 6 and serial number 7 under detection scheme of region 5; (f) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 7 and serial number 8 under detection scheme of region 6; (g) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 9 under detection scheme of region 7; (h) is a schematic diagram of ultrasonic C-scan signals of preformed defects at serial number 10 under detection scheme of region 8. DETAILED DESCRIPTION

[0019] The application will be described in detail below with reference to the drawings and embodiments.

[0020] It should be understood that the terms "upper end surface", "lower end surface", "inner side", "outer side" and the like in the embodiments indicate the positional relationship based on the positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0021] The core idea of the one-side ultrasonic oblique incidence full coverage detection method for crack defects of a rotary part is as follows: when detecting the crack at the step root of the rotary part, the crack occurrence area of the step root of the rotary part is divided into two adjacent areas A and B; the ultrasonic wave is obliquely incident from the end surface of one end of the rotary part, so that the refracted transverse wave only propagates between the two end surfaces of the rotary part, and the crack in the area A is detected; the ultrasonic wave is obliquely incident from the same end of the rotary part, so that the refracted transverse wave propagates by using the step, and the crack in the area B is detected.

[0022] It can be seen that the detection of region A is a conventional ultrasonic oblique incidence detection method, and the detection of region B is the key to realize full coverage detection of the step root crack at one end incidence under the premise of one clamping. This detection method ingeniously utilizes the structure of the step itself, so that all angles of cracks at both ends of the step root of the rotary part can be detected by ultrasonic oblique incidence from one end of the rotary part, solving the problem of needing to flip the rotary part upside down when detecting the step root cracks on the upper and lower end surfaces of the rotary part, improving the detection efficiency and reducing the labor intensity.

[0023] Based on the above core idea, taking a liquid rocket engine turbine pump wheel disc as an example, the specific scheme is as follows:

[0024] Step 1: Crack occurrence region division

[0025] The region between the extension lines of the step root and the abrupt surface is the crack occurrence region, which is prone to surface opening crack defects and is usually detected by end angle reflection. The angle coverage range of the crack occurrence region is generally 90°, and the cracks extending along the horizontal direction cannot form end angle reflection when obliquely incident from the upper surface. Therefore, in this embodiment, the angle bisector of the crack occurrence region is taken as the boundary to equally divide the crack occurrence region of each cross-section abrupt position into two 45° regions (i.e. 45° is taken as the critical angle), and detection schemes are designed respectively.

[0026] Specifically, as shown in Figure 1 The upper end surface and the lower end surface of a certain liquid rocket engine turbine pump wheel disc each have a closed cylindrical step (the middle of the step is a cavity), and there are four cross-section abrupt positions prone to crack defects at the inner and outer wall roots of the two steps. The angle of the crack extending along the horizontal direction is defined as a=0°, and the angle of the crack extending along the axial direction is defined as a=90°. Each crack occurrence region is divided into a=0°-45° and a=45°-90° two adjacent regions by the angle bisector of the two, and the four crack occurrence regions are divided into No. 1-8 regions: the outer root of the upper end surface step is divided into No. 1 region and No. 2 region (there is a critical angle of 45° between No. 1 region and No. 2 region), the inner root of the upper end surface step is divided into No. 3 region and No. 4 region, the outer root of the lower end surface step is divided into No. 5 region and No. 6 region, and the inner root of the lower end surface step is divided into No. 7 region and No. 8 region.

[0027] Step 2: Oblique incidence detection scheme design

[0028] Referring to Figure 2, the crack occurrence area of each cross-section mutation site is designed with an oblique incidence detection scheme. First, the area that can be detected by the traditional oblique incidence method (i.e., area A: No. 1, 3, 5, and 7 areas) is selected, and the detection is performed by once-refracted transverse waves or multiple-refracted transverse waves reflected by the upper and lower surfaces from the oblique incidence of the upper surface of the detected component; the area that cannot be covered by the traditional oblique incidence method (i.e., area B: No. 2, 4, 6, and 8 areas) is divided into two parts; for the upper area (No. 2 and 4 areas), the detection is performed by refracted transverse waves from the oblique incidence of the step side of the detected component on the side of area B; for the lower area (No. 6 and 8 areas), the detection is performed by using the reflection waves of the step cylindrical surface and the end surface from the oblique incidence of the upper end surface of the detected component on the side of area B. Through multi-surface oblique incidence and the use of structural reflection waves, single-side incidence full-coverage detection of crack defects at the cross-section mutation sites of the disc component is achieved.

[0029] Specifically, an oblique incidence detection scheme is designed for each area to be detected of the disc, and the ultrasonic propagation route in the detection process is as shown in Figure 2 In order to meet the principle of one-time clamping for detection, the crack defects of the eight areas are detected by refracted transverse waves from the oblique incidence of the upper end of the disc.

[0030] As shown in Figure 2 (a) and (b), for the crack defects of No. 1, 3, 5, and 7 areas with a crack angle α = 45°-90°, the detection is performed by the traditional oblique incidence method using the end angle reflection of the disc surface and the crack. Among them, according to the distribution of the steps (such as the distance of the steps from the edge of the disc), the structure (such as the height), and the size structure of the disc, for the crack defects of No. 1 and 3 areas at the root of the upper step, the detection is performed by twice-refracted transverse waves (No. 3 area can also use four times-refracted transverse waves, etc., but in order to reduce the energy attenuation of the sound beam and improve the signal-to-noise ratio, this embodiment selects the twice-refracted transverse waves with shorter sound wave path); for the crack defects of No. 7 area at the root of the lower step, the detection is performed by once-refracted transverse waves; for the crack defects of No. 5 area, in order to avoid the blocking of the incident sound beam by the upper step, the detection is performed by thrice-refracted transverse waves.

[0031] For the crack defects of No. 2, 4, 6, and 8 areas with a crack angle α = 0°-45°, if the detection is performed by the traditional oblique incidence method, the cracks in these areas cannot form end angle reflection, and if the disc is not flipped, they cannot be detected. In order to solve the above problem, a design as shown in Figure 2The detection scheme is shown. For crack defects in the upper step root 2 and 4 regions, the step surface and the end angle reflection of the crack are used, and the detection is carried out by once-refracted shear wave from the step cylindrical surface oblique incidence; for crack defects in the lower step root 6 and 8 regions, the step surface is used for detection by three times-reflected wave from the upper end surface of the disc to the lower step cylindrical surface (refracted shear wave is reflected on three surfaces of the step respectively and reaches the to-be-detected region). Figure 2 (c) Enlarged view of the sound propagation route for crack defect detection in regions 6 and 8.

[0032] Step 3: Detection sensitivity calibration

[0033] The sound propagation routes are different for detection in each region, and the sound time and energy attenuation degree are different, so the detection sensitivity needs to be calibrated by using artificial defect comparison samples.

[0034] The artificial defect comparison samples are designed and manufactured according to the relevant standards, according to the structure and size of the to-be-detected component, the material is the original material of the to-be-detected component, the limit size is covered, and the artificial defects are pre-prepared to cover the limit position of the crack occurrence area. The artificial defect calibration sample can be made into a whole circle, or can be made into a sector, and enough notch positions can be provided in the circumferential direction.

[0035] Specifically, according to the structure and size of the to-be-detected disc, artificial defect comparison samples as shown in Figure 3 (a) and (b) are designed and manufactured, which are used as simulation samples in this embodiment, the material is the original material of the to-be-detected disc, and the limit size of the cross-section mutation site of the to-be-detected disc is covered. Rectangular notches are used to simulate crack defects, and the pre-prepared notch size is 5mm×0.13mm×1mm (L×W×H), in order to cover the crack defect occurrence area of the cross-section mutation site, three special angles of 0°, 45° and 90° are pre-prepared respectively. The region to which the sample pre-prepared defect belongs is shown in Figure 3 (c), and the specific defect specifications are shown in Table 1.

[0036]

[0037] The artificial defect comparison sample is detected by 45° refracted shear wave, and for each to-be-detected region, the position of the corresponding incident point is calculated according to the sound propagation route planned by the detection scheme. As shown in Figure 4As shown in (a) and (b), for the crack defect with a crack angle α = 45°-90°, the distance from the incident point to the sudden change position of the section to be detected can be calculated as 2a (a is the height of the middle disc), 2a, 3a and a respectively, and the sound beam center is incident to the step root corresponding to the No. 1, No. 3, No. 5 and No. 7 regions; for the crack defect with a crack angle α = 0°-45°, the distance from the incident point to the sudden change position of the section to be detected can be calculated as b (b is the step width), b, c (c is obtained according to the sound propagation route) and c respectively, and the sound beam center is incident to the step root corresponding to the No. 2, No. 4, No. 6 and No. 8 regions.

[0038] The longitudinal wave propagation speed in water is 1480 m / s, and the transverse wave propagation speed in the sample is 3100 m / s. The oblique incidence angle of the longitudinal wave is calculated based on Snell's law, the sound propagation route planned according to the detection scheme and the sound speed of the medium material are combined to calculate the defect echo sound time of each region.

[0039] The probe is moved to the corresponding sound time position to obtain the A-scan signal of the defect, and the signal gain value for scanning detection is calibrated. 45° is taken as the limit angle of the end angle reflection, and the echo amplitude of the defect at this angle is relatively low, which is reduced by 3 dB compared with the defects at 0° and 90°. Therefore, the gain value is adjusted so that the echo amplitude of the prefabricated 45° defect reaches 80% of the full scale of the display screen, and the gain value at this time is taken as the calibration value. The A-scan signal of the prefabricated defect obtained by detection with the calibrated gain value is shown in Figure 5 The defect echo signal is marked with a black dashed line in the figure, the abscissa is the ultrasonic propagation time (referred to as sound time), and the ordinate is the normalized amplitude of the echo signal. The signal-to-noise ratio of A-scan detection is much higher than 6 dB, and 50% of the full scale of the display screen is taken as the gate threshold value for C-scan detection.

[0040] Step 4: scanning track planning for each detection region

[0041] Before realizing single-side oblique incidence full-coverage immersion scanning detection of the wheel disc component by using the manipulator ultrasonic scanning equipment, the manipulator track planning is needed. For each region to be detected, the profile line segment within 10 mm-20 mm on both sides of the center of the defect detection incident point calculated in step 3 is taken as the scanning region, and the oblique incidence scanning motion path of the manipulator holding probe is planned by using the industrial robot software to generate an executable track point package file.

[0042] Step 5: oblique incidence ultrasonic scanning detection

[0043] For each region to be detected, the scanning track obtained in step 4 is loaded, and the artificial defect comparison sample is subjected to oblique incidence ultrasonic immersion C-scan detection by using the manipulator ultrasonic scanning equipment, and the C-scan image of the prefabricated defect obtained is shown in Figure 6As shown, the black line frame in the figure represents the corresponding area of the sample, the abscissa is the distance of the probe moving along the circumferential direction (scanning direction) relative to the sample, and the ordinate is the distance of the probe moving along the generatrix direction (index direction) of the sample.

[0044] Specifically, in the detection process, a six-degree-of-freedom manipulator is used to hold the probe and move uniformly along the contour line direction of the part, while the turntable drives the detected part to rotate uniformly in one direction, and the spiral scanning is formed in cooperation.

[0045] From Figure 5 With Figure 6 As can be seen, by this method, all the rectangular grooves of the prefabricated simulated cracks can be detected, and the rectangular grooves at the critical angle (45° in this embodiment) can be detected under the detection method of their adjacent two regions, which shows that the detection method provided by the present application can cover the 0°-90° distribution angle range of the step root crack of the rotary part, so the method can be applied to the step root crack detection of various rotary parts.

[0046] It is worth noting that in this method, it is not necessary to divide the crack occurrence region by the critical angle bisector as the critical angle, but only to ensure that the defects at the critical angle can be detected under the detection scheme of the adjacent regions (such as region No. 1 and region No. 2; region No. 3 and region No. 4). Because the defects at the selected angle bisector in this embodiment can be detected under the adjacent detection scheme, that is, it is ensured that the cracks in the crack occurrence region (90° range) can be fully covered and detected, so other angles for dividing the crack region are not selected. If the defects at the selected critical angle cannot be detected under the detection scheme of the adjacent regions, only the critical angle needs to be changed until the above condition is met.

[0047] In summary, the above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for single-sided ultrasonic oblique incidence full coverage detection of crack defects of a rotary part, characterized in that: for a rotary part with closed cylindrical steps on the upper and lower end faces, crack defects are prone to occur at the four cross-section abrupt change positions of the inner and outer wall roots of the two end steps, the angle of a crack extending in the horizontal direction is defined as a = 0°, the angle of a crack extending in the axial direction is defined as a = 90°, the crack occurrence area is divided into two adjacent A and B regions of a = 0°-45° and a = 45°-90° by the angle bisector of the two angles, and the A and B regions are further subdivided into No. 1-8 regions: the upper end step outer root is divided into No. 1 and No. 2 regions, the upper end step inner root is divided into No. 3 and No. 4 regions, the lower end step outer root is divided into No. 5 and No. 6 regions, and the lower end step inner root is divided into No. 7 and No. 8 regions; for crack defects in No. 1, No. 3, No. 5 and No. 7 regions with a = 45°-90°, a traditional oblique incidence method is used to detect the end angle reflection of the crack between the wheel disc surface and the crack, wherein, according to the distribution, structure of the steps and the size structure of the rotary part, for crack defects in No. 1 and No. 3 regions of the upper step root, twice-refracted transverse waves are used for detection; for crack defects in No. 7 region of the lower step root, once-refracted transverse waves are used for detection; for crack defects in No. 5 region, thrice-refracted transverse waves are used for detection; for crack defects in No. 2, No. 4, No. 6 and No. 8 regions with a = 0°-45°, for crack defects in No. 2 and No. 4 regions of the upper step root, once-refracted transverse waves are used for detection by oblique incidence from the step cylindrical surface using the end angle reflection of the crack between the step surface and the crack; for crack defects in No. 6 and No. 8 regions of the lower step root, thrice-refracted waves of the lower step surface are used for detection by oblique incidence from the upper end face of the rotary part to the lower step cylindrical surface. Before crack detection, a defect comparison sample is used for detection sensitivity calibration. The defect comparison sample is provided with a rectangular notch at the crack occurrence area of the step root, which is at an angle of 0° or 90° with the end face of the defect comparison sample, and is also provided with a rectangular notch on the boundary line between the A and B regions. A manipulator is used for automatic ultrasonic C scanning of the rotary part.

2. The method according to claim 1, wherein the method is characterized by, The scanning scheme of the ultrasonic C scanning is spiral scanning.

3. The method according to claim 2, wherein the method is characterized by, The detection method used for the rotary part is ultrasonic oblique incidence water immersion detection.

4. The method according to any one of claims 1 to 3, wherein the method is a one-sided ultrasonic oblique incidence full coverage inspection method for a crack defect of a rotary body part, characterized in that, ​ 5. The method according to claim 4, wherein the method is characterized by, ​ 6. The single-side ultrasonic oblique incidence full coverage inspection method for cracks of a revolving part according to any one of claims 1 to 3 and 5, wherein ​

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