A fluorescent penetrant testing method for the inner wall surface of a long-axis type part

Abstract

The application discloses a kind of long axis class parts inner wall surface fluorescent penetrant testing method, belong to nondestructive testing technical field.First, from the long axis two ends of oblique placement respectively to inner wall surface spray fluorescent penetrant, long rod water spray gun is inserted into inner cavity cleaning from long axis two ends;Second, emulsifier is applied to long axis, drop, then first adopt long rod water spray gun from long axis two ends flush inner wall, make inner wall surface stop emulsification, again spray long axis outer surface, stop outer surface emulsification, emulsification time is not more than 2 minutes, dry;Again, using long rod negative pressure gun, developer is blown into long axis inner cavity, and developer is covered on the outer wall surface of long axis;Finally, long axis is placed horizontally and makes long axis rotate uniformly in circumferential direction, endoscope probe connected with support rod is inserted into long axis inner cavity at long axis two ends respectively, combined with axial movement scanning, the scanning inspection of different depth of entire long axis inner wall surface is completed, thereby solve the problem that long axis class parts inner wall surface fluorescent penetrant testing method exists blind area.

Description

Technical Field

[0001] This invention belongs to the field of nondestructive testing technology, specifically relating to a fluorescent penetrant testing method for the inner wall surface of long shaft-type parts. Background Technology

[0002] With the increasing demands on the strength and performance of aero-engines, higher requirements are being placed on non-destructive testing methods for engine components. Both during the manufacturing and operational phases, a wider testing scope and higher sensitivity are required. The low-pressure turbine shaft, a core component of an aero-engine, is a typical long-shaft part with a slender shape and hollow interior. In its operating environment, the low-pressure turbine shaft endures high temperatures, high pressures, and high stresses; even the slightest defect can lead to component failure and affect flight safety. Therefore, the inspection of every part of this type of component is crucial.

[0003] In the manufacturing and maintenance of low-pressure turbine shafts for aero-engines, non-destructive testing methods such as fluorescent penetrant testing and ultrasonic testing are required for quality control. However, due to the slender, hollow structure of the low-pressure turbine shaft, applying and removing penetrants to its inner wall presents difficulties, and blind spots exist during defect assessment. Consequently, the surface quality of the inner wall of this type of part cannot be assessed using conventional fluorescent penetrant testing. Therefore, there is an urgent need to develop fluorescent penetrant testing technology for the inner wall surfaces of long shaft-type parts to achieve the inspection and quality control of their inner surfaces. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a fluorescence penetrant detection method for the inner wall surface of long shaft parts, thereby solving the problem of blind spots in the fluorescence penetrant detection method for the inner wall surface of long shaft parts.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention discloses a method for detecting fluorescence penetrant on the inner wall surface of long shaft-type parts, the steps of which are as follows:

[0007] 1) Spray fluorescent penetrant onto the inner wall surface from both ends of the tilted long axis;

[0008] 2) Insert the long-handled water spray gun into the inner cavity from both ends of the long shaft to clean until no fluorescent penetrant flows out;

[0009] 3) Apply emulsifier to the long shaft and let it drip; on the premise of ensuring the emulsification effect, first use a long-handled water spray gun to rinse the inner wall from both ends of the long shaft to stop the emulsification of the inner wall surface, then spray and wash the outer surface of the long shaft to stop the emulsification of the outer surface. The emulsification time should not exceed 2 minutes.

[0010] 4) Clean the residual fluorescent penetrant on the inner and outer surfaces of the long axis under UV-A lamp monitoring, and then dry;

[0011] 5) Use a long-handled negative pressure gun to blow the developer into the inner cavity of the long shaft, so that the developer covers the inner wall surface of the long shaft; then cover the outer wall surface of the long shaft with developer.

[0012] 6) Rotate the long axis horizontally at a uniform speed in the circumferential direction. Insert the endoscope probes with support rods into the inner cavity of the long axis at both ends and move them along the axial direction of the inner cavity. Use the UV-A light source to complete the scanning inspection of the entire inner wall surface of the long axis at different depths in the circumferential and axial directions.

[0013] Preferably, in step 1), the spraying method is electrostatic spraying, the spraying temperature is 15-38℃, the electrostatic spray gun pressure is ≤200KPa, and the spraying time is 30 minutes.

[0014] Preferably, in step 1), the fluorescent penetrant is a post-emulsified fluorescent penetrant with level 4 sensitivity.

[0015] Preferably, in step 1), after spraying the fluorescent penetrant, the coverage of the fluorescent penetrant on the inner wall surface of the long axis is checked by a handheld UV-A lamp.

[0016] Preferably, in step 2), cleaning is performed under the monitoring of a VU-A lamp.

[0017] Preferably, in step 3), an emulsifier is applied to the long shaft using an impregnation method, and after impregnation, the long shaft is removed and dripped.

[0018] Preferably, in step 3), the emulsification time is calculated as follows: the emulsification time is calculated from the moment the long shaft contacts the emulsifier until all surfaces of the long shaft are rinsed.

[0019] More preferably, the spraying time is 50 seconds, the water temperature is 10-32℃, and the water pressure is ≤200KPa.

[0020] Preferably, in step 3), the concentration of the emulsifier is 6% to 8%.

[0021] Preferably, in step 4), a long-handled water spray gun is used to clean the residual fluorescent penetrant on the inner and outer surfaces of the long shaft.

[0022] Preferably, in step 4), after cleaning, compressed air is used to remove water from the long axis surface.

[0023] Preferably, in step 5), the pressure of blowing the developer powder is ≤200KPa until the developer powder covers the inner wall surface of the long axis, and then the powder blowing stops.

[0024] Preferably, in step 5), the developing powder is applied to the outer surface of the long axis by using a powder spraying cabinet to spray powder.

[0025] More preferably, in step 5), the powder spraying time is 3 seconds, followed by 15 minutes of development in the display cabinet.

[0026] Preferably, in step 6), the circumferential scanning area of ​​the endoscope probe is 15mm wide and the axial movement length is 10mm each time.

[0027] Preferably, in step 6), the fluorescence display observed by the endoscope probe is evaluated by wiping it with acetone solution using a long cotton swab. During the evaluation, the display is evaluated by switching between VU-A and white light sources.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention provides a fluorescent penetrant detection method for the inner wall surface of long shaft-type parts. First, by tilting the long shaft, the method ensures complete coverage of the inner wall with fluorescent penetrant, reducing penetrant accumulation and waste within the shaft's cavity and accelerating the removal of accumulated liquid. Second, applying the fluorescent penetrant to the inner wall from both ends of the long shaft ensures uniformity and integrity of the applied thickness. Third, before the emulsification time ends, a long-handled water spray gun is used to rinse the inner wall from both ends of the long shaft, and an automatic water spray washing tank is used to wash the outer surface of the long shaft at the end of emulsification. This allows for more precise control of the emulsification time of the inner wall and stricter control of the cleaning effect, avoiding over-emulsification and insufficient cleaning. Fourth, a long-handled negative pressure gun is used to blow developing powder into the inner cavity of the long shaft, ensuring complete coverage of the inner wall. Fifth, during the uniform circumferential rotation of the long shaft, an endoscope probe is inserted into the center of the shaft and moved axially, enabling 100% UV-A scanning detection of the inner wall surface, controlling the stability and coverage integrity of the detection process. This method employs specialized testing tools and fixtures (including but not limited to electrostatic spray guns, long-handled water spray guns, endoscopes, loading fixtures, and testing fixtures). On one hand, it establishes a unique process for applying and removing penetrants to the inner wall surface of long shaft-type parts, as well as for imaging. On the other hand, it determines the observation and evaluation method for the fluorescence display on the inner wall of long shaft-type parts, enabling comprehensive fluorescence penetrant detection of the inner wall surface of long shafts. Therefore, it can solve the long-standing problem of blind spots in the detection of the inner wall surface of long shaft-type parts.

[0030] Furthermore, applying the fluorescent penetrant by electrostatic spraying can further prevent the accumulation of fluorescent penetrant on the inner wall of the long axis. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the low-pressure turbine shaft loading and installation;

[0032] Figure 2 This is a cross-sectional view of the low-pressure turbine shaft;

[0033] Figure 3This is a schematic diagram of the stepwise emulsification process;

[0034] Figure 4 This is a schematic diagram of the inspection of the inner wall of a low-pressure turbine shaft.

[0035] Among them, 1-low-pressure turbine shaft; 2-feeding fixture; 3-endoscope; 4-support rod; 5-endoscope probe; 6-inspection fixture; 6-1-drive bearing; 6-2-driven bearing; 6-3-drive motor. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] This invention provides a method for detecting fluorescence penetrant on the inner wall surface of long shaft-type parts, the specific steps of which are as follows:

[0039] (1) Loading. In order to avoid liquid accumulation in the inner cavity of the long shaft during the permeation, cleaning, emulsification and drying process, and to accelerate the removal of liquid accumulation in the inner cavity of the long shaft, the long shaft is placed at an angle on the loading fixture 2. The long shaft is carried out together with the loading fixture 2 in steps (2) to (5). The loading fixture 2 has a certain slope, and the long shaft 1 can be placed at an angle on the loading fixture 2.

[0040] (2) Applying the penetrant. To avoid the accumulation of fluorescent penetrant on the inner wall of the long shaft, the fluorescent penetrant is applied by electrostatic spraying. The electrostatic spraying method should be used to spray the fluorescent penetrant onto the inner wall surface from both ends of the long shaft, and then check the coverage of the fluorescent penetrant on the inner wall surface of the long shaft with a handheld UV-A lamp until the fluorescent penetrant completely covers the inner wall surface of the long shaft before proceeding to the next step.

[0041] (3) Removal of penetrant. The steps of “removal of penetrant” include pre-cleaning, emulsification and final cleaning.

[0042] a) Pre-cleaning. A long-handled water spray gun is inserted into the inner cavity of the long shaft from both ends to manually clean the inner wall surface of the long shaft, removing most of the excess fluorescent penetrant; then an automatic water spray washing tank is used to automatically spray wash the outer surface of the long shaft.

[0043] b) Emulsification. Emulsification is a crucial step in fluorescence penetrant detection, and the emulsification time needs to be strictly controlled. The emulsification time is calculated from the moment the long shaft comes into contact with the emulsifier until all surfaces of the long shaft are rinsed with clean water. This invention employs a stepwise emulsification method: the emulsifier is applied to the long shaft using an immersion method, and after immersion, the long shaft is removed and dripped; to ensure the emulsification effect, a long-handled water spray gun is first used to rinse the inner wall from both ends of the long shaft to stop emulsification on the inner wall surface, and then the outer surface of the long shaft is sprayed to stop emulsification on the outer surface. The emulsification time is no more than 2 minutes, thereby achieving simultaneous cessation of emulsification on the entire inner and outer surfaces of the long shaft.

[0044] c) Final cleaning. Under UV-A lamp monitoring, a long-handled water spray gun is used to perform a final cleaning of the residual fluorescent penetrant on the inner and outer surfaces of the long shaft. The cleaning method is manual cleaning.

[0045] (4) Drying: Place the long shaft at 60-70℃ and dry for 15-20 minutes.

[0046] (5) Development: The developing powder is blown into the inner cavity of the long shaft using a long rod negative pressure gun, so that the developing powder covers the inner wall surface of the long shaft; then the developing powder is blown out by the powder spraying cabinet to cover the outer wall surface of the long shaft, thereby achieving the purpose of developing all surfaces of the inner and outer walls of the long shaft.

[0047] (6) Inspection: The long shaft is placed horizontally on the inspection fixture 6. The long shaft is rotated circumferentially at a uniform speed using the inspection fixture 6. The endoscope 3 is used to inspect the long shaft from both ends. The endoscope probe 5 is mounted on the support rod 4 and inserted into the inner cavity of the long shaft. The UV-A light source of the endoscope 3 is used to complete the circumferential scanning inspection of the inner wall surface of the long shaft. Then, the endoscope probe 5 is moved axially along the inner cavity of the long shaft to complete the axial scanning inspection of the inner wall surface of the long shaft by the endoscope probe 5 at different depths, thereby realizing the gradual and comprehensive inspection of the inner wall surface of the long shaft.

[0048] The inspection fixture 6 contains a drive motor 6-3, and a drive bearing 6-1 and a driven bearing 6-2 are horizontally mounted on its top. The drive bearing 6-1 and driven bearing 6-2 support the long shaft and drive it to rotate circumferentially. The working principle of the inspection fixture 6 is as follows: the drive motor 6-3 provides power, driving the drive bearing 6-1 to rotate circumferentially at a constant speed. The drive bearing 6-1 then supports and drives the long shaft to rotate circumferentially at a constant speed. Finally, with the support of the driven bearing 6-2, the long shaft drives the driven bearing 6-2 to rotate.

[0049] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0050] Taking the low-pressure turbine shaft of a certain aero-engine as an example, the fluorescent penetrant testing method is used to inspect the inner wall surface of long shaft-type parts. The steps are as follows:

[0051] (1) Loading materials. See also Figure 1 , will be Figure 2 The low-pressure turbine shaft 1 shown is placed at an angle on the loading fixture 2 with a slope of 3 degrees. The low-pressure turbine shaft 1 is carried out together with the loading fixture 2 in steps (2) to (5).

[0052] (2) Applying penetrant. At a temperature of 15–38°C, use an electrostatic spray gun to spray the inner wall surface of the low-pressure turbine shaft 1 with a post-emulsified fluorescent penetrant of level 4 sensitivity RC-77 from both ends. The pressure of the electrostatic spray gun is ≤200KPa. After spraying, leave for 30 minutes, and then check the coverage of the fluorescent penetrant on the inner wall surface of the low-pressure turbine shaft 1 with a handheld UV-A lamp.

[0053] (3) Removal of penetrant. a) Pre-cleaning: Under VU-A lamp monitoring, use a long-handled water spray gun to manually clean the inner surface of the low-pressure turbine shaft 1 from both ends into the inner cavity of the low-pressure turbine shaft 1. The water rinsing time should be as short as possible. If no obvious removable fluorescent penetrant flows out of the inner cavity, stop rinsing. Then, use an automatic spray washing tank to automatically spray wash the outer surface of the low-pressure turbine shaft 1 for 50 seconds, with a water temperature of 10-32℃ and a water pressure ≤200KPa. b) Emulsification: Start emulsification time from the time the low-pressure turbine shaft 1 comes into contact with the emulsifier, and stop emulsification time when all surfaces of the low-pressure turbine shaft 1 are rinsed with clean water. The emulsification time should not exceed 120 seconds. For specific emulsification steps, see [link to emulsification steps]. Figure 3At 0 seconds of emulsification, the low-pressure turbine shaft 1 is immersed in 6%–8% ER-83A emulsifier. At 20 seconds of emulsification, the low-pressure turbine shaft 1 is removed and dripped. At 90 seconds of emulsification, the inner wall of the low-pressure turbine shaft 1 is rinsed from both ends using a long-tube spray gun to stop emulsification on the inner wall surface. At 120 seconds of emulsification, the outer wall surface of the low-pressure turbine shaft 1 is sprayed with an automatic spray washing tank for 50 seconds, thereby stopping emulsification on the entire inner and outer surfaces of the low-pressure turbine shaft 1. c) Final cleaning: Under UV-A lamp monitoring, a long-handled water spray gun is used at a water temperature of 10–32℃ and a water pressure ≤200KPa to perform final cleaning of the residual fluorescent penetrant on the inner and outer walls of the low-pressure turbine shaft 1 until the fluorescent penetrant on the surface of the low-pressure turbine shaft 1 is completely removed, at which point rinsing is stopped. Then, compressed air is used to remove water from the surface of the low-pressure turbine shaft 1 at a pressure ≤100KPa, and a vacuum cleaner is used to remove water from the inner cavity.

[0054] (4) Drying: Place the low-pressure turbine shaft 1 into a hot air circulating oven for drying. The oven temperature is 60-70℃ and the drying time is 15-20 minutes.

[0055] (5) Development: Using a long-handled negative pressure gun, D-90G developer powder is blown into the inner cavity of the low-pressure turbine shaft 1, so that the D-90G developer powder covers the inner wall surface of the low-pressure turbine shaft 1. The blowing pressure is ≤200KPa and the blowing time is 2 seconds. Visual inspection is performed to ensure that the developer powder covers the inner wall surface of the low-pressure turbine shaft 1. Then, the D-90G developer powder is blown out of the powder in the powder spraying cabinet to cover the outer wall surface of the low-pressure turbine shaft 1. The powder is sprayed for 3 seconds and the image is left in the display cabinet for 15 minutes, thereby achieving the purpose of developing all surfaces of the inner and outer walls of the low-pressure turbine shaft 1.

[0056] (6) Verification: Using Figure 4 The method shown describes the inspection of the inner wall of the low-pressure turbine shaft 1 from both ends. The low-pressure turbine shaft 1 is placed horizontally on the inspection fixture 6, which rotates it circumferentially at a constant speed of 6 rpm. The endoscope probe 5 is mounted on the support rod 4 and inserted into the inner cavity of the low-pressure turbine shaft 1. The UV-A light source of the endoscope 3 is used to perform a circumferential scan of the inner wall surface of the low-pressure turbine shaft 1. The width of each circumferential scan area by the endoscope probe 5 is 15 mm. Then, the endoscope probe 5 is moved axially along the inner cavity of the low-pressure turbine shaft 1, moving 10 mm at a time, allowing for scanning inspections of the inner wall surface of the low-pressure turbine shaft 1 at different depths along the axial direction, thus achieving a gradual and comprehensive inspection of the inner wall surface of the low-pressure turbine shaft 1. The fluorescence observed by the endoscope 3 is evaluated after wiping with acetone solution using a long-handled cotton swab. During evaluation, the UV-A and white light sources can be switched for evaluation.

[0057] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for detecting fluorescence penetrant on the inner surface of a long shaft-type part, characterized in that, The steps are as follows: 1) Spray fluorescent penetrant onto the inner wall surface from both ends of the tilted long axis; 2) Insert the long-handled water spray gun into the inner cavity from both ends of the long shaft to clean until no fluorescent penetrant flows out; 3) Apply emulsifier to the long shaft and let it drip; on the premise of ensuring the emulsification effect, first use a long-handled water spray gun to rinse the inner wall from both ends of the long shaft to stop the emulsification of the inner wall surface, then spray and wash the outer surface of the long shaft to stop the emulsification of the outer surface. The emulsification time should not exceed 2 minutes. 4) Clean the residual fluorescent penetrant on the inner and outer surfaces of the long axis under UV-A lamp monitoring, and then dry; 5) Use a long-handled negative pressure gun to blow the developer into the inner cavity of the long shaft, so that the developer covers the inner wall surface of the long shaft; then cover the outer wall surface of the long shaft with developer. 6) Rotate the long axis horizontally at a uniform speed in the circumferential direction. Insert the endoscope probe (5) with the support rod (4) into the inner cavity of the long axis at both ends and move it along the axial direction of the inner cavity of the long axis. Use the UV-A light source to complete the scanning inspection of the entire inner wall surface of the long axis at different depths in the circumferential and axial directions.

2. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 1), the spraying method is electrostatic spraying, the spraying temperature is 15~38℃, the electrostatic spray gun pressure is ≤200KPa, and the spraying time is 30 minutes.

3. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 3), an emulsifier is applied to the long shaft using an impregnation method. After impregnation, the long shaft is removed and dripped.

4. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 3), the emulsification time is calculated as follows: the emulsification time is calculated from the moment the long shaft comes into contact with the emulsifier until all surfaces of the long shaft are rinsed.

5. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 3), the concentration of the emulsifier is 6% to 8%.

6. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 4), a long-handled water spray gun is used to clean the residual fluorescent penetrant on the inner and outer surfaces of the long shaft.

7. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 4), after cleaning, use compressed air to remove water from the long axis surface.

8. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 5), the pressure of blowing the developer powder is ≤200KPa until the developer powder covers the inner wall surface of the long axis, and then the powder blowing stops.

9. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 5), the developing powder is applied to the outer surface of the long axis by using a powder spraying cabinet to spray powder.

10. The fluorescence penetrant detection method for the inner wall surface of a long shaft-type part according to claim 1, characterized in that, In step 6), the endoscopic probe (5) scans a circumferential area of ​​15 mm and moves 10 mm axially each time.

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