Testing device for evaluating material gap corrosion performance
By designing a test device including a test plate, a partition, a gasket and fasteners to simulate the crevice corrosion environment of automobile panels, the problem of difficulty in evaluating crevice corrosion in the existing technology is solved, and the effects of quantitative evaluation and reduced test costs are achieved.
Patent Information
- Application Number
- CN202422710442.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2034-11-07
AI Technical Summary
Existing technologies are unable to effectively simulate and evaluate the crevice corrosion performance of materials, especially in the crevice locations of automotive panels, resulting in a high corrosion risk and making it difficult to meet the 10-year corrosion protection requirement of no rust.
A test device is designed, including a test plate, a separator, a gasket and fasteners. A gap is formed between the paint-free area and the separator through the gasket. The gap size is controlled to simulate the actual crevice corrosion environment. The corrosion acceleration test is carried out to quantitatively evaluate the crevice corrosion performance of the material.
It achieves quantitative evaluation of the crevice corrosion performance of materials, ensures that the anti-corrosion performance of automotive panels in terms of crevice corrosion meets product design requirements, reduces test costs and time, and improves test efficiency.
Smart Images
Figure CN223400795U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of metal processing, in particular to a test device for evaluating crevice corrosion performance of materials. Background Art
[0002] In order to meet the test requirements of 10-year rust-proofing for automobiles, automobile plates are protected against corrosion by pre-treatment and cathodic electrophoresis. However, it is difficult for the electrophoretic paint film to form continuously in the crevice locations such as the car body, and there is a risk of corrosion during service. Crevice corrosion is the most serious and common form of corrosion in automobiles, and it is also the most important cause of corrosion damage to automobiles.
[0003] Crevice corrosion mainly includes three common special forms: penetration corrosion, under-film corrosion, and deposition corrosion. Crevice corrosion occurs in various types of joints in automobiles. Currently, laboratories are unable to effectively simulate crevice corrosion, and there is an urgent need to develop a sample preparation device for quantitatively evaluating the crevice corrosion performance of materials. Utility Model Content
[0004] In order to solve the above problems, the present application provides a test device for evaluating the crevice corrosion performance of materials.
[0005] The present application provides a test device for evaluating the crevice corrosion performance of a material, comprising a test plate, a partition, a gasket and a fastener. The test plate presents a paint-free area and paint-film areas on opposite sides of the paint-free area on one thickness side. The partition is spaced apart from the paint-free area and the projection of the partition along the thickness direction coincides with the paint-free area. The gasket is arranged between the paint-free area of the test plate and the partition. The fastener passes through the test plate, the gasket and the partition in sequence to stack and fix the test plate, the gasket and the partition.
[0006] In some embodiments, the partition is a transparent plate.
[0007] In some embodiments, the material of the separator includes but is not limited to PETG.
[0008] In some embodiments, the materials of the gasket and the fastener include but are not limited to polytetrafluoroethylene.
[0009] In some embodiments, the fasteners are bolts, and the plate to be tested, the gasket, and the partition are all provided with through holes distributed along the thickness direction for the fasteners to pass through.
[0010] In some embodiments, the cross-sections of the test plate, the separator, and the gasket perpendicular to the thickness direction are all rectangular, and the paint film region and the paint film-free region are both rectangular.
[0011] In some embodiments, two gaskets are provided opposite to each other, and the two gaskets are respectively close to two opposite ends of the partition.
[0012] In some embodiments, the arrangement direction of the paint film area, the paint film-free area and the other paint film area is the same as the length direction of the gasket, the length of the gasket is equal to the size of the partition along the arrangement direction, and the length side of the gasket is flush with the side of the partition along the arrangement direction.
[0013] In some embodiments, the panel to be tested is an automobile panel, and the paint film in the paint film area is an electrophoretic paint film.
[0014] In some embodiments, the thickness of the spacer is 0.15 mm to 0.3 mm.
[0015] The beneficial effects of the present application are as follows: a test device for evaluating the crevice corrosion performance of a material is provided, comprising a test plate, a partition, a gasket and a fastener, wherein the gasket is arranged between the paint-free area of the test plate and the partition, the test plate, the gasket and the partition are fixedly connected by the fastener, a gap is formed between the paint-free area of the test plate and the partition by the gasket, the thickness of the gasket is the size of the gap, and the gap size is controlled by controlling the thickness of the gasket; the paint film area is an area coated with a paint film, and the paint-free area is an area not coated with a paint film, by arranging paint film areas on both sides of the paint-free area on one thickness side of the test plate, the paint-free area represents an area where no paint film is formed when the paint film is difficult to be continuous in the plate, and the relative distribution of the partition and the test plate is measured. The specific definition is that the projection of the partition along the thickness direction is coincident with the paint-free area of the test plate, which is reflected in that the four edges of the partition are flush with the four edges of the paint-free area. It simulates the actual situation that the plate represented by the test plate (such as automobile plate) is difficult to be continuous in certain gap positions during coating, and simulates the environment in which the plate represented by the test plate (such as automobile plate) will suffer from crevice corrosion during use when it is installed in the product. When the test device is assembled, subsequent corrosion acceleration tests can be carried out. By obtaining the corrosion effect of the paint-free area of the test plate, the quantitative evaluation of the crevice corrosion performance of the test plate material can be successfully achieved. The evaluation results ensure that the anti-corrosion performance of the plate represented by the test plate in crevice corrosion meets the product design requirements. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention.
[0017] Figure 1 A schematic diagram of a test plate in a test device for evaluating crevice corrosion performance of a material provided in this application;
[0018] Figure 2 A top view of a test device for evaluating the crevice corrosion performance of materials provided in this application;
[0019] Figure 3 This is a front view of a test device for evaluating the crevice corrosion performance of materials provided in this application.
[0020] Figure markings: 10 - test plate, 11 - paint film area, 12 - non-paint film area, 20 - partition, 30 - gasket, 40 - fastener, 51 - first direction, 52 - second direction, 53 - thickness direction. DETAILED DESCRIPTION
[0021] This application provides a test device for evaluating the crevice corrosion performance of materials, hereinafter referred to as the test device, please refer to Figure 3 The test device includes a test plate 10, a partition 20, a gasket 30 and a fastener 40.
[0022] Figure 3 The thickness direction 53 is shown in FIG. Figure 1 and Figure 2 A first direction 51 and a second direction 52 are shown, and the first direction 51 , the second direction 52 and the thickness direction 53 are perpendicular to each other. Figure 1 The facing side of the graphic in the figure is the thickness side of the test board 10, and the thickness side of the test board 10 is sequentially presented as a paint film area 11, a non-paint film area 12, and another paint film area 11, and the arrangement direction of the paint film area 11, the non-paint film area 12, and the other paint film area 11 is a first direction 51. The paint film area 11 is an area coated with a paint film, and the non-paint film area 12 is an area not coated with a paint film. By arranging the paint film area 11 on both sides of the non-paint film area 12 on the thickness side of the test board 10, the non-paint film area 12 represents the area where no paint film is formed when the paint film is difficult to be continuous in the plate represented by the test board 10. The test device provided in this application simulates the actual situation that the paint film of the plate represented by the test board 10 is difficult to be continuous at certain gap positions during coating.
[0023] Please refer to Figures 1 to 3 The spacer 20 is spaced apart from the paint-free area 12 and the gasket 30 is disposed between the paint-free area 12 of the test plate 10 and the spacer 20. The test plate 10, the gasket 30, and the spacer 20 are stacked in sequence, and the stacking direction is the thickness direction 53. The test plate 10, the gasket 30, and the spacer 20 are stacked and fixed by fasteners 40, which pass through the test plate 10, the gasket 30, and the spacer 20 in sequence. Please refer to Figure 3 A gap is formed between the paint-free area 12 of the test plate 10 and the partition 20 through the gasket 30. The thickness of the gasket 30 is the size of the gap. By controlling the thickness of the gasket 30, the size of the gap can be controlled.
[0024] The above definition of the partition 20 and the paint-free area 12 is spaced apart and opposite to each other. This application also specifically defines the relative distribution of the partition 20 and the test plate 10. Please refer to Figures 1 to 3 The projection of the partition plate 20 along the thickness direction 53 coincides with the paint-free area 12 of the test plate 10 , meaning that the edges of the partition plate 20 are flush with the edges of the paint-free area 12 . This simulates the actual situation in which a continuous paint film may form at certain crevice locations during coating of the plate represented by the test plate 10 (e.g., an automotive plate). It also simulates the environment in which crevice corrosion may occur in the plate represented by the test plate 10 (e.g., an automotive plate) when installed in a product and during use.
[0025] After the test device is assembled, subsequent corrosion acceleration tests can be carried out. By obtaining the corrosion effect of the paint-free area 12 of the test plate 10, a quantitative evaluation of the crevice corrosion performance of the test plate 10 material can be successfully achieved. The evaluation results ensure that the anti-corrosion performance of the plate represented by the test plate 10 meets the product design requirements.
[0026] When an automobile plate is coated with an anti-corrosion paint film, the paint film is generally an electrophoretic paint film, which will cause the problem of the electrophoretic paint film being difficult to be continuous at multiple gaps in the car body, thereby posing a corrosion risk during the service life of the car. This type of corrosion is crevice corrosion, which occurs at various types of connection parts of the car, such as the edging of the inner and outer panels of the four doors and two covers of the car, spot welding parts, rivet connection parts, bolt and screw connection parts, rubber strip bonding parts, and decorative strip bonding parts. These parts all have a large number of gaps. When the test plate 10 in the test device of the present application is made from an automobile plate, specifically an automobile plate whose crevice corrosion performance needs to be verified, the paint film area 11 in the test plate 10 is an electrophoretic paint film. The test device of the present application can measure the crevice corrosion performance of the material of the test plate 10, ensuring that the anti-corrosion performance of this type of automobile plate in terms of crevice corrosion meets the test requirements of 10 years of rust-proof.
[0027] On the other hand, compared with some test methods in which samples are made through complex automobile parts connection methods such as welding and gluing, the test device of the present application only needs to prepare a test plate 10 including a paint film area 11 and a paint-free area 12. The present application scheme has the advantage of rapid sample preparation, which is beneficial to reducing the test cost and test time for verification of gap corrosion resistance performance, improving test efficiency, promoting the application of strategic products such as zinc-aluminum-magnesium automobile plates at the user end, and creating significant economic and social benefits.
[0028] In some embodiments, the thickness of the gasket 30 is 0.15 mm to 0.3 mm, including endpoints of 0.15 mm and 0.3 mm. The inventors have found that because gaps larger than 0.3 mm on automobiles will partially form an electrophoretic film, the gap effect is not significant; and the degree of crevice corrosion in gaps smaller than 0.15 mm on automobiles is very small. Therefore, in this method, the thickness of the gasket 30 is 0.15 mm to 0.3 mm, and the gap size between the test plate 10 and the separator 20 is controlled within the range of 0.15 mm to 0.3 mm, which has significant guiding significance for verifying the crevice corrosion performance of automobile plates.
[0029] In some embodiments, the thickness of the gasket 30 is further set to 0.15 mm-0.2 mm, including endpoints of 0.15 mm and 0.2 mm.
[0030] In some embodiments, see Figure 3 The fastener 40 is a bolt. The plate to be tested 10, the gasket 30 and the partition 20 are all provided with through holes. The through holes are distributed along the thickness direction 53 of the part. The through holes of the plate to be tested 10, the gasket 30 and the partition 20 are aligned and the fastener 40 is passed through the through holes to smoothly assemble the plate to be tested 10, the gasket 30 and the partition 20.
[0031] In some embodiments, when the thickness of the gasket 30 is 0.15 mm-0.3 mm, the pitch of the fastener 40 when it is a bolt is 0.35 mm, and the pitch of 0.35 mm matches the thickness of the gasket 30 .
[0032] The fastener 40 is not limited to being implemented in a bolt, and may also be a pin, a rivet, etc. However, the advantage of a bolt is that it is easy to assemble and disassemble, which is more conducive to test operations.
[0033] It should be noted that the separator 20, gasket 30, and fastener 40 must all meet the requirement of not participating in the electrochemical reaction of the components during the salt spray corrosion process. In some embodiments, the separator 20 is a transparent plate, which facilitates subsequent observation of corrosion products through the transparent plate 20, allowing online monitoring of the test process.
[0034] In some embodiments, the material of the partition 20 is PETG, the full name of PETG is polyethylene terephthalate-1,4-cyclohexanedimethanol ester. The PETG partition 20 has outstanding toughness and high impact strength, and has high mechanical strength, excellent flexibility and transparency, and has outstanding practical effects in actual applications.
[0035] On the basis that the material of the partition 20 meets the requirements of plate transparency and does not participate in the electrochemical reaction of the components during salt spray corrosion, the material of the partition 20 is not limited to PETG, and other materials such as glass can also be used.
[0036] In some embodiments, the gasket 30 and the fastener 40 are made of polytetrafluoroethylene, which has good stability and is not easily deformed. In addition to polytetrafluoroethylene, the gasket 30 and the fastener 40 can also be made of other materials such as polyethylene.
[0037] The above definition states that the projection of the partition 20 along the thickness direction 53 coincides with the paint film-free area 12. In some embodiments, please refer to Figure 1 and Figure 2 The shape of the cross section of the test plate 10 perpendicular to the thickness direction 53, the shape of the cross section of the partition plate 20 perpendicular to the thickness direction 53, and the shape of the cross section of the gasket 30 perpendicular to the thickness direction 53 can be obtained from Figure 2 As can be seen in FIG, the cross-sections of the test plate 10 , the partition plate 20 and the gasket 30 perpendicular to the thickness direction 53 are all rectangular, and the paint film area 11 and the non-paint film area 12 are also rectangular.
[0038] In some embodiments, see Figure 2 and Figure 3 Two gaskets 30 are provided opposite to each other, and the two gaskets 30 are respectively close to the opposite ends of the partition 20.
[0039] The arrangement direction of the paint film region 11, the non-paint film region 12 and the other paint film region 11 is defined as the first direction 51. In some embodiments, please refer to Figure 2 The first direction 51 is the same as the length direction of the gasket 30. The length of the gasket 30 is equal to the dimension of the partition 20 along the first direction 51. The length side of the gasket 30 is flush with the side of the partition 20 along the first direction 51. The two gaskets 30 as above block the opposite sides of the gap.
[0040] In some embodiments, when the fastener 40 is a bolt, the bolt diameter is 1.6 mm-2 mm, and the nut diameter is 4.6 mm-5 mm.
[0041] In some embodiments, see Figure 2The thickness of the partition 20 is 2mm-3mm, the dimension of the partition 20 along the second direction 52 is the length of the partition 20, and the length of the partition 20 is 70mm. The dimension of the partition 20 along the first direction 51 is the width of the partition 20, and the width of the partition 20 is 40mm. There are four through holes in the partition 20 for the installation of the fastener 40. The four through holes are respectively located at the four corners of the partition 20, and the diameter of the through holes is 2.6mm-3mm. It should be noted that the gap span where crevice corrosion occurs in automobile panels is generally 8mm-10mm. In this method, the width of the partition 20 is set to 40mm. The width of the partition 20 is larger than the required simulated gap span, which makes it easier to observe the test results of the subsequent corrosion acceleration test.
[0042] The thickness of the gasket 30 is 0.15mm-0.3mm, please refer to Figure 2 The dimension of the gasket 30 along the first direction 51 is the length of the gasket 30, and the length of the gasket 30 is 40 mm. The dimension of the gasket 30 along the second direction 52 is the width of the gasket 30, and the width of the gasket 30 is 10 mm. Each gasket 30 has two through holes, and the aperture of the through holes is 2.6 mm-3 mm.
[0043] Please refer to Figure 1 The length of the test board 10 is 150 mm, the width of the test board 10 is 70 mm, the side lengths of the paint-free area 12 are 40 mm and 70 mm respectively, and the apertures of the four through holes opened in the test board 10 are 2.6 mm-3 mm.
[0044] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0045] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.
Claims
1. A test device for evaluating the crevice corrosion performance of a material, characterized in that: include: The test plate has a non-paint film area on one side of the thickness and paint film areas on two opposite sides of the non-paint film area; a partition, spaced apart and opposite to the paint-free area, wherein a projection of the partition in a thickness direction coincides with the paint-free area; a gasket, provided between the paint-film-free area of the test plate and the partition; The fastener passes through the plate to be tested, the gasket and the partition in sequence, and is used to stack and fix the plate to be tested, the gasket and the partition.
2. The test device for evaluating the crevice corrosion performance of a material according to claim 1, characterized in that: The partition is a transparent plate.
3. The test device for evaluating the crevice corrosion performance of a material according to claim 2, characterized in that: The material of the partition is PETG.
4. The test device for evaluating the crevice corrosion performance of a material according to claim 1, characterized in that: The gasket and the fastener are made of polytetrafluoroethylene.
5. The test device for evaluating the crevice corrosion performance of a material according to claim 1, characterized in that: The fasteners are bolts, and the plate to be tested, the gasket and the partition are all provided with through holes for the fasteners to pass through and distributed along the thickness direction.
6. The test device for evaluating the crevice corrosion performance of a material according to claim 1, characterized in that: The cross-sections of the test plate, the partition plate, and the gasket perpendicular to the thickness direction are all rectangular, and the paint film area and the non-paint film area are both rectangular.
7. The test device for evaluating the crevice corrosion performance of a material according to claim 6, characterized in that: Two gaskets are provided opposite to each other, and the two gaskets are respectively close to the opposite ends of the partition.
8. The test device for evaluating the crevice corrosion performance of a material according to claim 7, characterized in that: The arrangement direction of the paint film area, the paint film-free area and the other paint film area is the same as the length direction of the gasket, the length of the gasket is equal to the size of the partition along the arrangement direction, and the length side of the gasket is flush with the side of the partition along the arrangement direction.
9. The test device for evaluating the crevice corrosion performance of a material according to any one of claims 1 to 8, characterized in that: The board to be tested is an automobile board, and the paint film in the paint film area is an electrophoretic paint film.
10. The test device for evaluating the crevice corrosion performance of a material according to claim 9, characterized in that: The thickness of the gasket is 0.15mm-0.3mm.