A detection method for detecting internal structure of a light alloy

Abstract

The present application belongs to the technical field of automobile steering wheel detection, and particularly relates to a detection method for internal organization detection of light alloy, comprising the following steps: S1 sampling, S2 sample grinding, S3 polishing, S4 cleaning, S5 pore detection, S6 corrosion treatment, S7 metallographic detection, S8 judgment and S9 screening. The method simplifies the inlaying processing steps, does not need additional inlaying materials and complex inlaying equipment, uses plasticine to adhere and fix the sampling block, is simple and convenient to operate, and places the qualified sampling block on the workbench and the unqualified sampling block on the moving vehicle body, so that the qualified and unqualified sampling blocks can be classified and processed. The present application reduces the detection cost and improves the accuracy of the detection structure.

Description

Technical Field

[0001] This invention relates to the field of automotive steering wheel testing technology, and more specifically, to a testing method for detecting the internal structure of lightweight alloys. Background Technology

[0002] With the rapid development of the automotive industry and the increasing demands of consumers for automotive safety and comfort, the steering wheel, as an important component of the automotive control system, is receiving more and more attention for its quality and performance. Steering wheel components are usually made of a variety of materials, including metals, plastics, and composite materials. The selection of these materials and the processing of these materials have a crucial impact on the overall performance of the steering wheel. In order to ensure the quality and performance of steering wheel components, these components need to be rigorously tested.

[0003] For example, the metallographic sample preparation and characterization method for MOX fuel pellets disclosed in application publication number CN115524186A includes the following steps: Step 1: Selecting the sample; Step 2: Mounting treatment; Step 3: Grinding the sample; Step 4: Polishing the sample; Step 5: Etching the sample; Step 6: Low-magnification observation; Step 7: High-magnification observation.

[0004] In the above-mentioned case, sulfur powder is used to mount the sample. This requires purchasing sulfur powder as a mounting material and the corresponding mounting mold equipment, which increases the testing cost. For lightweight alloys, which are relatively soft, the mounting process may cause some damage to the sample and affect the accuracy of the test results. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for detecting the internal structure of lightweight alloys that is simple to operate, low in cost, and has high detection accuracy.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for detecting the internal structure of a lightweight alloy, comprising the following steps:

[0008] S1 sampling: Take a sampling block from the steering wheel;

[0009] S2 Grinding Sample: Place 180, 1500, 2000, 2500, 3000 and 5000 grit abrasive cloths into the metallographic sample polishing machine in sequence, and grind the sample block.

[0010] S3 Polishing: Place the polishing cloth in the metallographic sample polishing machine, and apply 3-micron high-grade alumina polishing powder, 1-micron high-grade alumina polishing powder and 0.5-micron high-grade alumina polishing powder to the polishing cloth in sequence. Polish the sample block after six grindings three times.

[0011] S4 Cleaning: Pour alcohol onto the surface of the sampling block to remove the polishing powder. Pour alcohol onto the surface of the sampling block again and dry the surface of the sampling block with a hair dryer.

[0012] S5 Porosity Detection: Embed the dried sample block into the clay and place it under a metallographic microscope to obtain porosity data and observe whether the data is qualified;

[0013] S6 Etching Treatment: Add 50ml of water and 5ml of nitric acid to a glass container and stir to form an etching liquid; remove the sample block from the clay and immerse it in the etching liquid until white crystals appear on the surface of the sample block after etching.

[0014] S7 Metallographic Examination: Take another sample block, embed it into the clay, and place it under a metallographic microscope to obtain metallographic data;

[0015] S8 Judgment: Combining porosity testing and metallographic testing, determine whether the sample block is qualified;

[0016] S9 Screening: Place qualified sampling blocks on the workbench and unqualified sampling blocks on the moving vehicle.

[0017] The present invention is further configured such that in steps S5 and S7, the sampling block is embedded in the clay in different postures and the sampling block is tested.

[0018] The present invention is further configured as follows: In step S5, the sample block is analyzed under a metallographic microscope. First, the sample block is photographed, and three rectangles are obtained from the photograph. The porosity of the three rectangular areas is analyzed to obtain the porosity data.

[0019] The present invention is further configured such that: in step S6, the immersion time of the sample block surface is 30-50 seconds.

[0020] The present invention is further configured such that: when the sampling block is being tested, the clay in which the sampling block is embedded is fixed and adjusted by a fixing component;

[0021] The fixing assembly includes a fixing frame, a positioning plate, and several positioning rods. The fixing frame is in the shape of a cylindrical tube, and several sets of corresponding through holes are formed on the side wall of the fixing frame.

[0022] A positioning rod can pass through a set of through holes, and several positioning rods can cooperate to form placement surfaces with different tilt angles, and the positioning plate is placed on the placement surface.

[0023] The present invention is further configured such that the positioning disk is composed of a mesh plate.

[0024] The present invention is further configured such that: the positioning rod is composed of a rod body and a positioning head, the rod body can pass through a through hole, and the cross-sectional area of ​​the positioning head is larger than the diameter of the through hole.

[0025] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0026] Simplified mounting process: The sampling block is fixed by bonding with modeling clay, eliminating the need for additional mounting materials and complex mounting equipment. This avoids the damage that traditional mounting methods may cause to the sample and reduces the testing cost.

[0027] Improved detection accuracy: Through multi-stage grinding and polishing, uneven parts and impurities on the surface of the sampling block can be effectively removed, making the surface of the sampling block smoother and flatter, which is beneficial for subsequent porosity detection and metallographic detection, and improves the accuracy of the detection results.

[0028] Efficient cleaning process: The combination of alcohol cleaning and hair dryer drying can thoroughly clean the surface of the sampling block of polishing powder and other residues, ensuring the cleanliness of the sampling block surface and providing good conditions for subsequent testing.

[0029] Multi-angle inspection: In the porosity inspection and metallographic inspection steps, the sample block can be embedded in the clay in different postures for inspection, realizing all-round inspection of the sample block and enabling a more comprehensive evaluation of the internal structure of the sample block.

[0030] Precise porosity detection: Utilizing the porosity module of a metallurgical microscope, three rectangular regions are automatically acquired and their porosity analyzed through photography and image processing technology. This allows for precise determination of whether the porosity meets the standards, improving the accuracy and reliability of porosity detection.

[0031] Optimized corrosion treatment: By controlling the immersion time of the sampling block in the corrosive liquid (30-50 seconds), it is possible to remove surface impurities while avoiding excessive corrosion that could obscure the microstructure, thus ensuring the quality and accuracy of metallographic testing.

[0032] Convenient metallographic testing: After etching, the sample block is re-embedded in clay and placed under a metallographic microscope. Through the metallographic module's imaging and image processing functions, the distribution and arrangement of white crystals can be clearly observed. Combined with the metallographic standard rating spectrum, the efficiency and accuracy of metallographic testing are improved.

[0033] Effective classification and processing: Qualified and unqualified sampling blocks are placed on the workbench and mobile vehicle respectively, which facilitates the classification and processing of test results and is beneficial to subsequent production management and quality control.

[0034] Innovative fixing component: The fixing component is designed to fix and adjust the clay with the embedded sampling block, forming a placement surface with different tilt angles, which increases the flexibility and adaptability of sampling block testing, and improves the convenience and efficiency of testing.

[0035] Enhanced friction and stability: The positioning plate is made of a grid plate, which increases the friction with the clay, allowing the clay to be stably fixed on the positioning plate and improving the stability of the sampling block during the testing process.

[0036] Magnetic adsorption fixation: The positioning head is embedded with a magnet, which can attract the fixing frame and ensure that the positioning rod is stably fixed on the fixing frame, further improving the stability and reliability of the entire fixing assembly. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process of the present invention;

[0038] Figure 2 This is a schematic diagram of the modules on the metallurgical microscope of the present invention;

[0039] Figure 3 This is the porosity detection sample of the present invention;

[0040] Figure 4 This is the metallographic testing sample of the present invention;

[0041] Figure 5 This is a schematic diagram of the workbench of the present invention;

[0042] Figure 6 This is an exploded view of the fixing component of the present invention;

[0043] Figure 7 This is a schematic diagram of the structure of the fixing component of the present invention;

[0044] Figure 8 This is a diagram showing the usage state of the fixing component of the present invention.

[0045] 1. Fixing bracket; 2. Positioning plate; 3. Positioning rod; 4. Through hole; 5. Rod body; 6. Positioning head; 7. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] like Figures 1 to 5 As shown, the workflow is as follows: First, a sample block is cut from the steering wheel. Then, the sample block is inlaid, ground, polished, and cleaned. Next, the sample block is subjected to porosity testing. After the porosity testing is completed, the sample block is subjected to etching treatment. After the etching treatment, the sample block is subjected to metallographic testing. Finally, the pass rate of the sample block is determined.

[0049] The detection method for the internal structure of lightweight alloys includes the following steps: Step 1: Cut a sampling block from the steering wheel.

[0050] Step 2: Adjust the metallographic sample polishing machine to normal working condition. Place polishing cloths of 180, 1500, 2000, 2500, 3000 and 5000 grit into the metallographic sample polishing machine. Polish the sample block six times on each of the polishing cloths of 180, 1500, 2000, 2500, 3000 and 5000 grit respectively until the surface of the sample block is smooth.

[0051] During placement, the polishing cloth is placed inside the metallographic sample polishing machine, and the protective ring on the metallographic sample polishing machine is placed on the polishing cloth to fix the polishing cloth on the metallographic sample polishing machine. Then, the sampling block is placed on the polishing cloth for polishing. By polishing the surface of the sampling block from coarse to fine, the uneven parts of the sampling block surface can be gradually removed, making it smoother and flatter. In the later measurement of porosity and metallography, its structure and distribution can be observed and analyzed more accurately. Since the sampling wheel may be covered with grease, dust or fingerprints, the sampling block may also be covered with grease, dust or fingerprints. Through six polishings, these grease, dust or fingerprints can be effectively removed to ensure the accuracy of the measurement.

[0052] Step 3: Place the polishing cloth in the metallographic sample polishing machine. First, add 3-micron high-grade alumina polishing powder to the polishing cloth and perform the first polishing on the sample block. Then, add 1-micron high-grade alumina polishing powder to the polishing cloth and perform the second polishing on the sample block. Finally, add 0.5-micron high-grade alumina polishing powder to the polishing cloth and perform the third polishing on the sample block. This process, from coarse polishing to fine polishing, can improve the surface smoothness of the sample block, remove rough scratches on the surface, and make the surface of the sample block smoother and more even.

[0053] Step 4: Pour alcohol onto the surface of the sample block after three polishing processes to remove the polishing powder and perform the first cleaning. Pour alcohol onto the cleaned sample block surface again for a second cleaning. Finally, use a hair dryer to dry the sample block surface and further remove the polishing powder to ensure the cleanliness of the sample block surface.

[0054] Step 5: Embed the dried sample block into the clay. The clay with the sample block embedded can be fixed and adjusted using the fixing component. Then move the fixing component to place the dried sample block under the metallographic microscope with the sample block facing upwards. The magnification of the metallographic microscope is 100x. The metallographic microscope includes a pore module and a metallographic module. Both the pore module and the metallographic module include an imaging module and an image processing module.

[0055] First, the sampling block is photographed using the imaging module on the porosity module to obtain a photo. The image processing module on the porosity module then identifies the photo and automatically extracts three rectangles from it. These three rectangles include an inner frame at the center of the sampling block and two outer frames placed on either side of the inner frame. When the porosity within the inner frame is ≤10% and the porosity within the outer frames is ≤5%, the porosity is considered acceptable. When the porosity within the inner frame is ≥10% and the porosity within the outer frames is ≥5%, the porosity is considered unacceptable. The porosity is analyzed using the three rectangles to obtain porosity data. If the porosity of any one of the three rectangles is unacceptable, the sampling block is considered unacceptable.

[0056] Step 6: Add 50ml of water and 5ml of nitric acid to a glass container and stir to form a corrosive liquid. Stirring will make the water and nitric acid more evenly mixed. Remove the sample block with the porosity test results from the clay and then immerse the sample block in the corrosive liquid.

[0057] If the immersion time is 30 seconds, the surface structure of the sample block cannot be fully revealed, and metallographic data cannot be detected later. If the immersion time is 50 seconds, the corrosion time is too long, and the surface of the sample block will be excessively eroded, causing the surface structure of the sample block to become blurred and damaging the microstructure of the sample block. If the immersion time is 40 seconds, the surface of the sample block is clear. Therefore, the heating time is preferably 40 seconds.

[0058] The sampling block may contain grease, dust, or fingerprints, which can interfere with observation under a metallographic microscope, causing the image to become blurry or distorted. Etching can effectively remove these greases, dust, or fingerprints, obtaining a clear metallographic image. If these greases, dust, or fingerprints are not removed, white crystals will form on the surface of the sampling block through etching.

[0059] Step 7: Embed the etched sample block into the clay. Alternatively, the clay with the embedded sample block can be fixed and adjusted using a fixing component. Then, move the fixing component to place the dried sample block under a metallographic microscope. The metallographic microscope is set to 100x magnification. First, take a picture of the sample block using the imaging module on the metallographic module. Then, use the image processing module on the metallographic module to identify the picture. The picture will show black and white states. Black represents bubbles, and white represents white crystals. Combine image analysis technology to observe the distribution of white crystals.

[0060] When the white crystals in the photograph exhibit a uniform structure, fine texture, and densely arranged pores, this condition corresponds to the fourth level of the metallographic standard rating chart. At this point, the sample block can be judged as qualified; otherwise, it is unqualified, and metallographic data can be obtained.

[0061] Step 8: Combining porosity testing and metallographic testing, determine whether the sample block is qualified. If the test result shows that the porosity is qualified and meets the fourth level standard of the metallographic standard rating chart, the sample block is qualified. If the test result shows that the porosity is qualified but the white crystals do not show a uniform structure, fine white crystals and densely arranged pores, the sample block is unqualified.

[0062] Step 9: Place the qualified sampling blocks on the workbench and the unqualified sampling blocks on the moving vehicle. Push the moving vehicle to retest the unqualified sampling blocks, which facilitates the classification and processing of qualified and unqualified sampling blocks.

[0063] Because clay can be freely shaped, it can be molded into spheres, blocks, cones, and other forms, allowing the sample to be viewed at any angle under a microscope, thus enabling omnidirectional testing. Furthermore, clay can stably fix the sample at the angle to be tested.

[0064] like Figure 6 The diagram shows the structure of the fixing component, which includes a fixing frame 1, a positioning plate 2 and several positioning rods 3. The fixing frame 1 is in the shape of a cylindrical tube. Several sets of corresponding through holes 4 are opened on the side wall of the fixing frame 1 from top to bottom. The positioning rods 3 are composed of rod body 301 and positioning head 302. The rod body 301 can pass through the through hole 4. The cross-sectional area of ​​the positioning head 302 is larger than the diameter of the through hole 4.

[0065] In steps five and seven, when the sampling block is being tested, the clay with the sampling block embedded in it can be further fixed and adjusted using the fixing components. The positioning plate 2, which is composed of a grid plate, increases the friction between the clay and the clay, allowing the clay to be stably fixed on the positioning plate 2. The fixing frame 1 can be made of steel, and the positioning head 302 can be embedded with a magnet to attract the fixing frame 1, ensuring that the positioning is stably fixed on the fixing frame 1.

[0066] like Figure 7 As shown, if the positioning disk 2 is to be placed horizontally, the rod body 301 of the positioning rod 3 passes horizontally through a corresponding set of through holes 4, and several positioning rods 3 can form a horizontal placement surface for the positioning disk 2 to be placed horizontally.

[0067] like Figure 8As shown, if the positioning disk 2 is to be placed at an angle, the rod body 301 of the positioning rod 3 passes through a corresponding set of through holes 4 at an angle. Several positioning rods 3 can form an inclined placement surface for the positioning disk 2 to be placed at an angle. By changing the angle of inclination of the placement surface, different postures of the clay with the sampling block embedded can be adjusted.

[0068] In the porosity detection step, image analysis technology is used to accurately measure porosity and determine whether the porosity of the steering wheel components meets the standard. In the metallographic detection step, image analysis technology is used to determine that the white crystal remetallographic standard rating spectrum meets the fourth level standard, and the sample block is judged to be qualified. Then, by combining porosity detection method and metallographic detection method, the strength and toughness of the steering wheel can be accurately evaluated.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting the internal structure of a lightweight alloy, characterized in that, Includes the following steps: S1 sampling: Take a sampling block from the steering wheel; S2 Grinding Sample: Place 180, 1500, 2000, 2500, 3000 and 5000 grit abrasive cloths into the metallographic sample polishing machine in sequence, and grind the sample block. S3 Polishing: Place the polishing cloth in the metallographic sample polishing machine, and apply 3-micron high-grade alumina polishing powder, 1-micron high-grade alumina polishing powder and 0.5-micron high-grade alumina polishing powder to the polishing cloth in sequence. Polish the sample block after six grindings three times. S4 Cleaning: Pour alcohol onto the surface of the sampling block to remove the polishing powder. Pour alcohol onto the surface of the sampling block again and dry the surface of the sampling block with a hair dryer. S5 Porosity Detection: Embed the dried sample block into the clay and place it under a metallographic microscope to obtain porosity data and observe whether the data is qualified; S6 Etching Treatment: Add 50ml of water and 5ml of nitric acid to a glass container and stir to form an etching liquid; remove the sample block from the clay and immerse it in the etching liquid until white crystals appear on the surface of the sample block after etching. S7 Metallographic Examination: Take another sample block, embed it into the clay, and place it under a metallographic microscope to obtain metallographic data; S8 Judgment: Combining porosity testing and metallographic testing, determine whether the sample block is qualified; S9 Screening: Place qualified sampling blocks on the workbench and unqualified sampling blocks on the moving vehicle. In steps S5 and S7, the sampling block is embedded in the clay in different orientations, and the sampling block is then tested. During the testing process, the clay containing the sampling block is fixed and adjusted using a fixing component. The fixing component includes a fixing frame (1), a positioning plate (2) and several positioning rods (3). The fixing frame (1) is in the shape of a round tube, and several sets of through holes (4) corresponding to each other are opened on the side wall of the fixing frame (1). A positioning rod (3) can pass through a set of through holes (4), and several positioning rods (3) can cooperate to form a placement surface with different tilt angles, and the positioning plate (2) is placed on the placement surface; The positioning disk (2) is composed of a grid plate; The positioning rod (3) consists of a rod body (301) and a positioning head (302). The rod body (301) can pass through the through hole (4), and the cross-sectional area of ​​the positioning head (302) is larger than the diameter of the through hole (4). The positioning head (302) is embedded with a magnet for adsorbing the fixing frame (1). If the positioning disk (2) is to be placed horizontally, then the rod body (301) of the positioning rod (3) passes horizontally through a corresponding set of through holes (4) and several positioning rods (3) form a horizontal placement surface for the positioning disk (2) to be placed horizontally; If the positioning plate (2) is to be placed at an angle, then the rod body (301) of the positioning rod (3) passes through a corresponding set of through holes (4) at an angle, and several positioning rods (3) form an angled placement surface for the positioning plate (2) to be placed at an angle.

2. The detection method for the internal structure of a lightweight alloy according to claim 1, characterized in that, In step S5, the sample block is analyzed under a metallographic microscope. First, the sample block is photographed, and three rectangles are obtained from the photograph. The porosity of the three rectangular areas is analyzed to obtain the porosity data.

3. The detection method for the internal structure of a lightweight alloy according to claim 1, characterized in that, In step S6, the surface of the sample block is immersed for 30-50 seconds.

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