Method for detecting surface cracks of multi-layer sealing thin-wall part

Abstract

The invention provides a multi-layer sealing thin-wall part surface crack detection method which comprises the following steps: firstly, placing a multi-layer sealing thin-wall part in a high-pressure helium tank for storage for a certain time, taking out the part, placing the part in a ventilation environment or blowing the part by using clean air to remove helium molecules attached to the part, and then taking out the part; the product is placed in a helium mass spectrometer leak detector, helium molecules stored between thin walls of the part with cracks on the surface can escape through the surface cracks in an evacuation environment, and whether through cracks exist on the surface of the product or not is determined by detecting that the leak rate is larger than a threshold value through the helium mass spectrometer leak detector. In a word, the method has the advantages of being high in detection efficiency, not prone to missing detection and suitable for batch detection.

Description

Technical Field

[0001] The invention relates to the technical field of elastic sensitive element helium mass spectrometer leak detection, in particular to a method for detecting surface cracks of multi-layer sealed thin-wall parts. Background Art

[0002] Multi-layer sealed thin-walled parts are very commonly used in the aerospace field. They are generally required to have a long service life and be able to work under pressure for a long time. The working conditions are relatively harsh. If there are through cracks on the surface of the parts during use, stress concentration will occur at the cracks, which will reduce the service life and cause liquid to enter the gap, thereby causing the thin walls to be easily corroded. Traditional single-layer thin-walled parts can use the method of inflating the inner cavity of the part or adding negative pressure to detect surface defects, but the effect is not good. Although there is a sealed space between the thin walls of multi-layer sealed thin-walled parts with better performance, the use effect is improved. However, when there are through cracks on only a single layer of the surface, the existing methods cannot be used for screening. The only way is to visually inspect the cracks on the outer surface with a microscope, inspecting one piece at a time, which is very inconvenient and inefficient. At the same time, these traditional visual inspection methods also have the problems of low efficiency and a high probability of missed detection due to the complex surface structure, and cannot meet the existing production needs of the design. Therefore, there is an urgent need for a surface crack detection method for multi-layer sealed thin-walled parts to solve the above-mentioned problems. Summary of the invention

[0003] In view of this, the present invention proposes a method for detecting surface cracks in multi-layer sealed thin-walled parts, which is applied to the technical field of helium mass spectrometry leak detection of elastic sensitive elements to solve the technical problems of low detection efficiency, easy missed detection and unsuitability for mass production.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for detecting surface cracks of multi-layer sealed thin-walled parts comprises the following steps:

[0006] S1. Place the multi-layer sealed thin-walled parts in a high-pressure helium tank for a certain period of time, so that helium molecules can enter the thin-wall gaps through the surface cracks;

[0007] S2. Take out the parts and place them in a ventilated environment or use clean air to blow on the parts to remove all helium molecules attached to the parts to avoid interference with subsequent test results;

[0008] S3. Place the product in a helium mass spectrometer leak detector. In an evacuated environment, the helium molecules stored between the thin walls of parts with cracks on the surface will escape through the surface cracks. The helium mass spectrometer leak detector detects that the leakage rate is greater than the threshold value to confirm whether there are through cracks on the product surface.

[0009] Furthermore, the model of the helium mass spectrometer leak detector is D-35614ASSLAR, and the threshold value is 1x10^-10Pa.m^3 / s. If the vacuum degree is less than 1x10^-10Pa.m^3 / s, and the leak rate detected by the helium mass spectrometer leak detector is greater than the threshold value, it is confirmed that there are through cracks on the surface of the product.

[0010] Furthermore, in step S1, the multi-layer sealed thin-walled parts are placed in a high-pressure helium tank for 6 hours.

[0011] Furthermore, in step S2, the parts are taken out and placed in a ventilated environment for 12 hours.

[0012] Furthermore, in step S2, the parts are sprayed with clean air for 1 hour.

[0013] Furthermore, in step S3, the multi-layer sealed thin-walled parts are placed in a vacuum container for detection, and the detection part of the helium mass spectrometer leak detector extends into the vacuum container.

[0014] Furthermore, in step S3, the multi-layer sealed thin-walled part is bent and extended, and a bracket matching the shape of the multi-layer sealed thin-walled part is provided in the vacuum container, so as to support the multi-layer sealed thin-walled part during the detection process of the multi-layer sealed thin-walled part.

[0015] The present invention has the following beneficial effects:

[0016] The method for detecting surface cracks on multi-layer sealed thin-walled parts mentioned in the present invention is suitable for batch detection of products. Multiple products are placed in a high-pressure helium tank and a helium mass spectrometer leak detector at the same time. The leakage rate tested by the helium mass spectrometer leak detector is used to judge whether there are through cracks on the surface of the batch of products. The method has high detection efficiency and is not prone to missed detection, and is suitable for large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic structural diagram of a multi-layer sealing thin-walled part in a specific embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the connection between the multi-layer sealed thin-walled parts and the vacuum container in a specific embodiment of the present invention;

[0020] Among them: 1. Multi-layer sealed thin-walled parts; 2. Vacuum containers. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0023] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any of the several aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the form, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0025] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0026] Example 1

[0027] like Figure 1 and Figure 2 As shown, a method for detecting surface cracks of multi-layer sealed thin-walled parts comprises the following steps:

[0028] S1, placing the multi-layer sealed thin-walled component 1 in a high-pressure helium tank for a certain period of time, so that helium molecules enter the thin-wall gaps through the surface cracks;

[0029] S2. Take out the parts and place them in a ventilated environment or use clean air to blow on the parts to remove all helium molecules attached to the parts to avoid interference with subsequent test results;

[0030] S3. Place the product in a helium mass spectrometer leak detector. In an evacuated environment, the helium molecules stored between the thin walls of parts with cracks on the surface will escape through the surface cracks. The helium mass spectrometer leak detector detects that the leakage rate is greater than the threshold value to confirm whether there are through cracks on the product surface.

[0031] The model of the helium mass spectrometer leak detector is D-35614ASSLAR, and the threshold value is 1x10^-10Pa.m^3 / s. If the vacuum degree is less than 1x10^-10Pa.m^3 / s, it is considered that the leak rate detected by the helium mass spectrometer leak detector is greater than the threshold value, and it is confirmed that there are through cracks on the surface of the product. In step S1, the multi-layer sealed thin-walled part 1 is placed in a high-pressure helium tank for 6 hours. In step S2, the part is taken out and placed in a ventilated environment for 12 hours.

[0032] In step S3, the multi-layer sealed thin-walled part 1 is placed in a vacuum container for detection, and the detection part of the helium mass spectrometer leak detector extends into the vacuum container. In step S3, the multi-layer sealed thin-walled part 1 is bent and extended, and a bracket matching the shape of the multi-layer sealed thin-walled part 1 is provided in the vacuum container, thereby supporting the multi-layer sealed thin-walled part 1 during the detection process of the multi-layer sealed thin-walled part 1.

[0033] Example 2

[0034] Different from Example 1, in step S2, the parts are sprayed with clean air for 1 hour, the model of the helium mass spectrometer leak detector in the step is D-35614ASSLAR, and the threshold value is 1x10^-10Pa.m^3 / s. If the vacuum degree is less than 1x10^-10Pa.m^3 / s, it is considered that the leakage rate detected by the helium mass spectrometer leak detector is greater than the threshold value, and it is confirmed that there are through cracks on the surface of the product.

[0035] The present invention relates to a method for detecting surface cracks of multi-layer sealed thin-walled parts. The method adopts a helium back pressure method to detect surface cracks of multi-layer sealed thin-walled parts. The method utilizes the strong permeability of helium molecules and the existence of gaps between the thin walls of multi-layer sealed thin-walled parts. The method has the advantages of high detection efficiency, low risk of missed detection and suitability for batch detection.

[0036] 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 shall be subject to the protection scope of the claims.

Claims

1. A method for detecting surface cracks of multi-layer sealed thin-walled parts, characterized in that: Including steps The steps are as follows: S1. Place the multi-layer sealed thin-walled component (1) in a high-pressure helium tank for a certain period of time. The helium molecules enter the thin wall gap through the surface cracks; S2. Take out the parts and place them in a ventilated environment or use clean air to blow on the parts. Remove all helium molecules attached to parts to avoid interference with subsequent test results; S3. Place the product in a helium mass spectrometer leak detector and check if there are cracks on the surface of the product in an evacuated environment. Helium molecules stored between thin walls of components will escape through surface cracks and be detected by a helium mass spectrometer leak detector. If the leakage rate is greater than the threshold, it can be confirmed whether there are through cracks on the surface of the product.

2. The method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 1, characterized in that: The model of the helium mass spectrometer leak detector in step 1 is D-35614ASSLAR, and the threshold value is 1x10^-10Pa.m^3 / s. If the vacuum degree is less than 1x10^-10Pa.m^3 / s, it is considered that the leak rate detected by the helium mass spectrometer leak detector is greater than the threshold value, and it is confirmed that there are through cracks on the surface of the product.

3. A method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 2, characterized in that: In the step S1, the multi-layer sealed thin-walled component (1) is placed in a high-pressure helium tank and stored for 6 hours.

4. A method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 3, characterized in that: In step S2, the parts are taken out and placed in a ventilated environment for 12 hours.

5. A method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 4, characterized in that: In step S2, the parts are sprayed with clean air for 1 hour.

6. A method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 5, characterized in that: In the step S3, the multi-layer sealed thin-walled component (1) is placed in a vacuum container for detection, and the detection part of the helium mass spectrometer leak detector extends into the vacuum container.

7. A method for detecting surface cracks of multi-layer sealed thin-walled parts according to claim 6, characterized in that: In step S3, the multi-layer sealed thin-walled part (1) is bent and extended, and a bracket matching the shape of the multi-layer sealed thin-walled part (1) is provided in the vacuum container, so as to support the multi-layer sealed thin-walled part (1) during the inspection process of the multi-layer sealed thin-walled part (1).

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