Metallographic specimen grinding and polishing method
By using grinding and polishing discs to polish composite metallographic samples multiple times, the problems of high material consumption and long cycle time are solved, achieving efficient and low-cost metallographic sample preparation, and improving detection efficiency and analytical accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI AIRCRAFT MFG
- Filing Date
- 2026-03-20
- Publication Date
- 2026-04-28
AI Technical Summary
In the existing technology, the grinding and polishing process of composite metallographic specimens is characterized by high material consumption, long cycle time, high cost, and complex operation, resulting in low detection efficiency.
Grinding discs and polishing discs of different precision are used to grind and polish metallographic samples of composite materials, replacing traditional sandpaper and polishing cloth. The grinding and polishing efficiency and stability are improved through multiple polishing processes.
It significantly reduced the amount of consumables used and the frequency of replacement, shortened the processing cycle, improved the surface finish of the samples and the accuracy of the analysis results, reduced costs, and improved detection efficiency and process autonomy.
Smart Images
Figure CN121928455A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metallographic analysis technology, and in particular to a method for grinding and polishing metallographic samples. Background Technology
[0002] Composite materials, due to their superior mechanical properties such as lightweight, high specific strength, and high specific modulus, are increasingly widely used in aerospace and aviation fields. However, the special ply structures formed during the design and processing of composite materials, as well as unavoidable defects such as porosity and delamination during production, directly affect their mechanical properties and application scenarios. Metallographic analysis can directly reflect the morphology of the internal structure of composite materials, and therefore plays an important role in their analysis and application. To ensure that the internal morphology of the tested material can be accurately displayed during metallographic analysis, a high degree of surface finish is required for the sample; therefore, metallographic sample preparation usually requires a grinding and polishing process.
[0003] In existing polishing techniques, the sample must first be ground with coarse sandpaper to expose its internal morphology. However, in actual production tests, composite metallographic samples are mostly hand-cut, resulting in extremely uneven surfaces, often exhibiting problems such as localized depressions, protrusions, missing corners, and deep tool marks. These issues become more pronounced with thicker samples. This leads to long metallographic grinding cycles and high sandpaper consumption: for relatively smooth samples, each batch (4-6 samples) requires 2-4 sheets of sandpaper; while for uneven samples, it requires more than ten or even twenty sheets (each sheet lasts only 30-60 seconds). Changing sandpaper is cumbersome, and with a large number of samples, the overall preparation cycle is significantly extended, severely impacting efficiency. After metallographic grinding, multiple polishing processes—coarse, fine, and high-precision—are required. To ensure stable and controllable polishing quality, imported polishing cloths and slurries are typically used, resulting in high costs. In practice, frequent manual addition of polishing slurry is necessary, while automatic addition equipment is not only expensive but also prone to clogging. Meanwhile, polishing cloths have a short lifespan and lack obvious failure characteristics. Often, the cause is only located after polishing quality problems occur, requiring a step-by-step troubleshooting process. This not only relies on the operator's experience but also consumes a significant amount of time. When there are many samples to be tested, it can easily lead to sample backlog, affecting the overall testing progress.
[0004] Therefore, there is an urgent need for a metallographic sample polishing method to solve the above-mentioned technical problems. Summary of the Invention
[0005] The purpose of this invention is to provide a metallographic sample grinding and polishing method to reduce the grinding and polishing cost of composite metallographic samples and improve the grinding and polishing efficiency of composite metallographic samples.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] This invention provides a metallographic sample polishing method for polishing composite metallographic samples. The metallographic sample polishing method includes: step S100, using a grinding disc to perform metallographic grinding on the composite metallographic sample; step S200, using a first-type polishing disc to perform a first metallographic polishing on the composite metallographic sample; and step S300, using a second-type polishing disc to perform a second metallographic polishing on the composite metallographic sample. The polishing precision of the second-type polishing disc is greater than that of the first-type polishing disc.
[0008] In some embodiments, step S100 includes: step S110, placing the composite metallographic sample on the surface of the grinding disc; step S120, applying a first pre-pressure to the composite metallographic sample; the direction of the first pre-pressure is towards the surface of the grinding disc; step S130, rotating the grinding disc to perform metallographic grinding on the composite metallographic sample for a first preset time.
[0009] In some embodiments, the grinding disc is a diamond particle grinding disc; the mesh size of the grinding disc ranges from 500 mesh to 700 mesh.
[0010] In some embodiments, the first pre-pressure ranges from 7.5N to 12.5N; the first preset duration ranges from 5 minutes to 10 minutes.
[0011] In some embodiments, step S200 includes: step S210, placing the metallographic sample of the composite material after metallographic grinding on the surface of the first type of polishing pad; step S220, applying a second pre-pressure to the metallographic sample of the composite material; the direction of the second pre-pressure is towards the surface of the first type of polishing pad; step S230, rotating the first type of polishing pad to perform the first metallographic polishing of the metallographic sample of the composite material for a second preset time.
[0012] In some embodiments, the polishing disc is a diamond polishing disc; the polishing particle size range of the polishing disc is 8 micrometers to 10 micrometers.
[0013] In some embodiments, the second pre-pressure ranges from 30N to 40N; the second preset duration ranges from 5 minutes to 10 minutes.
[0014] In some embodiments, step S300 includes: step S310, placing the composite metallographic sample that has undergone the first metallographic polishing on the surface of the second type of polishing disc; step S320, applying a third pre-pressure to the composite metallographic sample; the direction of the third pre-pressure is towards the surface of the second type of polishing disc; step S330, rotating the second type of polishing disc to perform a second metallographic polishing on the composite metallographic sample for a third preset time.
[0015] In some embodiments, the second type of polishing disc is a diamond polishing disc; the polishing particle size range of the second type of polishing disc is 0.4 micrometers to 0.6 micrometers.
[0016] In some embodiments, the third pre-pressure ranges from 30N to 40N; the third preset duration ranges from 5 minutes to 10 minutes.
[0017] The beneficial effects of this invention are:
[0018] This invention provides a metallographic sample polishing method. It utilizes a polishing disc to perform metallographic grinding on composite metallographic samples, replacing the traditional method of using metallographic abrasive paper. Because the polishing disc has high overall structural strength and a much longer service life than traditional abrasive paper, frequent replacement of consumables is unnecessary during a single composite metallographic sample polishing process, significantly reducing consumable usage and replacement time, and substantially lowering material and labor costs. Simultaneously, the polishing disc can stably and continuously perform uniform grinding on the surface of the composite metallographic sample, resulting in higher grinding efficiency and more stable removal capabilities. It can quickly eliminate defects such as deep knife marks, unevenness, and missing corners on the surface of hand-cut samples. Especially for thicker composite metallographic samples, it can significantly shorten the overall polishing cycle and improve the polishing efficiency of a single batch of samples, effectively solving the problems of long polishing cycles and sample backlog associated with traditional abrasive paper. Furthermore, using a grinding disc for grinding makes the grinding process more stable and the force more uniform. This avoids differences in grinding degree caused by uneven wear of sandpaper, untimely replacement, or inconsistent manual pressure, resulting in higher consistency of sample surface grinding. This provides a more uniform and flat pretreatment foundation for subsequent polishing processes, which is beneficial to improving the surface smoothness and morphological authenticity of the final composite metallographic sample, and improving the accuracy and reliability of metallographic analysis results. Furthermore, when polishing composite metallographic samples using the aforementioned metallographic sample polishing method, the first and second polishing processes are performed using two types of polishing discs with different polishing precisions. This replaces the traditional method of using polishing cloth and polishing fluid. Because the polishing discs have high structural strength and excellent wear resistance, their service life is much longer than that of traditional polishing cloths, allowing for long-term reuse. This significantly reduces the frequency of purchasing and replacing consumables, effectively lowering the overall polishing cost. It also eliminates dependence on imported consumables, improving the autonomy and economy of the process. Since the polishing discs do not need frequent replacement, multiple samples can be polished continuously in batches, effectively solving the problems of sample backlog and long testing cycles caused by cumbersome procedures and complex operations in traditional processes, greatly improving the processing efficiency of batch samples. Simultaneously, the traditional polishing method is simplified to two steps: a first polishing (rough polishing) and a second polishing (fine polishing). Polishing is directly completed using two types of polishing discs with different polishing precisions, significantly shortening the polishing time for a single sample and improving polishing efficiency. Furthermore, since the quality of the polishing pad is easy to judge, the polishing process is more stable and uniform, which can effectively avoid quality defects caused by uneven wear of the polishing cloth or inconspicuous failure. This significantly improves the stability and controllability of polishing quality, reduces the dependence on the operator's experience, and makes the process easier to standardize and promote. Attached Figure Description
[0019] Figure 1 This is a flowchart of a metallographic sample polishing method provided in a specific embodiment of the present invention;
[0020] Figure 2 This is a flowchart of step S100 in a metallographic sample polishing method provided in a specific embodiment of the present invention;
[0021] Figure 3 This is a flowchart of step S200 in a metallographic sample polishing method provided in a specific embodiment of the present invention;
[0022] Figure 4 This is a flowchart of step S300 in a metallographic sample polishing method provided in a specific embodiment of the present invention. Detailed Implementation
[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.
[0024] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0026] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.
[0027] like Figure 1 As shown, this embodiment provides a metallographic sample polishing method for polishing composite metallographic samples. The metallographic sample polishing method includes:
[0028] Step S100: Metallographic grinding of the composite metallographic sample is performed using a grinding disc. Step S200: A first metallographic polishing of the composite metallographic sample is performed using a first-type polishing disc. Step S300: A second metallographic polishing of the composite metallographic sample is performed using a second-type polishing disc. The polishing precision of the second-type polishing disc is greater than that of the first-type polishing disc. It is easy to understand that polishing precision is inversely proportional to polishing grit size; the smaller the polishing grit size of a polishing disc, the higher its polishing precision. In other words, the polishing grit size of the second-type polishing disc is smaller than that of the first-type polishing disc.
[0029] Therefore, the metallographic sample polishing method provided in this embodiment uses a polishing disc to perform metallographic grinding on composite metallographic samples, replacing the traditional method of using metallographic abrasive paper. Because the polishing disc has high overall structural strength and a much longer service life than traditional metallographic abrasive paper, there is no need to frequently replace consumables during a single composite metallographic sample polishing process, significantly reducing consumable usage and replacement time, and substantially lowering material and labor costs. Simultaneously, the polishing disc can stably and continuously perform uniform grinding on the surface of the composite metallographic sample, resulting in higher grinding efficiency and more stable removal capabilities. It can quickly eliminate defects such as deep knife marks, unevenness, and missing corners on the surface of hand-cut samples. Especially for thicker composite metallographic samples, it can significantly shorten the overall polishing cycle and improve the polishing efficiency of a single batch of samples, effectively solving the problems of long polishing cycles and sample backlog associated with traditional metallographic abrasive paper. Furthermore, using a grinding disc for grinding makes the grinding process more stable and the force more uniform. This avoids differences in grinding degree caused by uneven wear of sandpaper, untimely replacement, or inconsistent manual pressure, resulting in higher consistency of sample surface grinding. This provides a more uniform and flat pretreatment foundation for subsequent polishing processes, which is beneficial to improving the surface smoothness and morphological authenticity of the final composite metallographic sample, and improving the accuracy and reliability of metallographic analysis results. Furthermore, when polishing composite metallographic samples using the aforementioned metallographic sample polishing method, the first and second polishing processes are performed using two types of polishing discs with different polishing precisions. This replaces the traditional method of using polishing cloth and polishing fluid. Because the polishing discs have high structural strength and excellent wear resistance, their service life is much longer than that of traditional polishing cloths, allowing for long-term reuse. This significantly reduces the frequency of purchasing and replacing consumables, effectively lowering the overall polishing cost. It also eliminates dependence on imported consumables, improving the autonomy and economy of the process. Since the polishing discs do not need frequent replacement, multiple samples can be polished continuously in batches, effectively solving the problems of sample backlog and long testing cycles caused by cumbersome procedures and complex operations in traditional processes, greatly improving the processing efficiency of batch samples. Simultaneously, the traditional polishing method is simplified to two steps: a first polishing (rough polishing) and a second polishing (fine polishing). Polishing is directly completed using two types of polishing discs with different polishing precisions, significantly shortening the polishing time for a single sample and improving polishing efficiency. Furthermore, since the quality of the polishing pad is easy to judge, the polishing process is more stable and uniform, which can effectively avoid quality defects caused by uneven wear of the polishing cloth or inconspicuous failure. This significantly improves the stability and controllability of polishing quality, reduces the dependence on the operator's experience, and makes the process easier to standardize and promote.
[0030] In some embodiments, such as Figure 2As shown, step S100 includes: step S110, placing the composite metallographic sample on the surface of the grinding disc; step S120, applying a first pre-pressure to the composite metallographic sample, the direction of which is towards the surface of the grinding disc; and step S130, rotating the grinding disc to perform metallographic grinding on the composite metallographic sample for a first preset time. When applying the first pre-pressure to the composite sample, a CNC pressure-applying device from related technologies can be used, or the clamping device inherent in the grinding and polishing equipment can be used to apply pressure, ensuring the accuracy of the applied first pre-pressure.
[0031] For example, the aforementioned grinding disc is a diamond particle grinding disc. The grinding disc includes a substrate and a working layer. The substrate is, for example, a metal disc or a resin disc, and the working layer is a layered structure in which diamond particles are uniformly bonded (electroplated, resin-bonded, or metal-bonded) on the surface of the substrate. The mesh size of the grinding disc ranges from 500 mesh to 700 mesh. For example, the mesh size of the grinding disc is 500 mesh; or 550 mesh; or 600 mesh; or 650 mesh; or 700 mesh. Preferably, the mesh size of the grinding disc is 600 mesh.
[0032] Further, the range of the first pre-pressure is 7.5N to 12.5N. For example, the first pre-pressure is 7.5N; or 8N; or 10N; or 12N; or 12.5N. Preferably, the first pre-pressure is 10N. The range of the first preset time is 5 minutes to 10 minutes. For example, the first preset time is 5 minutes; or 6 minutes; or 7.5 minutes; or 8 minutes; or 10 minutes. It is easy to understand that since the smoothness of the outer surface of the composite metallographic specimen varies, those skilled in the art can flexibly set the specific values of the first pre-pressure and the first preset time according to actual usage requirements, and will not be listed exhaustively here.
[0033] In some embodiments, such as Figure 3As shown, step S200 includes: step S210, placing the metallographic sample of the composite material after metallographic grinding onto the surface of a polishing pad. Step S220, applying a second pre-pressure to the metallographic sample of the composite material, the direction of which is directed towards the surface of the polishing pad. Step S230, rotating the polishing pad to perform a first metallographic polishing of the metallographic sample of the composite material for a second preset time. After step S210 and before step S220, step S211 can also be performed: spraying water onto the surface of the polishing pad. This setup improves the polishing effect and eliminates the need for polishing fluid, saving polishing costs.
[0034] For example, the aforementioned type of polishing disc is a diamond polishing disc. This type of polishing disc includes a substrate and a working layer. The substrate is, for example, a metal disc or a resin disc, and the working layer is a layered structure in which diamond abrasive (micro powder) is uniformly solidified (electroplated, resin-bonded, or metal-bonded) on the surface of the substrate. The polishing particle size of this type of polishing disc ranges from 8 micrometers to 10 micrometers. For example, the polishing particle size of this type of polishing disc is 8 micrometers; or 8.5 micrometers; or 9 micrometers; or 9.5 micrometers; or 10 micrometers. Preferably, the polishing particle size of this type of polishing disc is 9 micrometers.
[0035] Furthermore, the range of the second pre-pressure is 30N to 40N. For example, the second pre-pressure is 30N; or 32N; or 35N; or 38N; or 40N. The range of the second preset time is 5 minutes to 10 minutes. For example, the second preset time is 5 minutes; or 6 minutes; or 7.5 minutes; or 8 minutes; or 10 minutes. It is easy to understand that since the smoothness of the outer surface of the composite metallographic specimen varies, those skilled in the art can flexibly set the specific values of the second pre-pressure and the second preset time according to actual usage requirements, and will not be listed exhaustively here.
[0036] In some embodiments, such as Figure 4As shown, step S300 includes: Step S310, placing the composite metallographic sample, after the first metallographic polishing, onto the surface of the second-type polishing disc. Step S320, applying a third pre-pressure to the composite metallographic sample, the direction of which is directed towards the surface of the second-type polishing disc. Step S330, rotating the second-type polishing disc to perform a second metallographic polishing of the composite metallographic sample for a third preset duration. After step S310 and before step S320, step S311 can also be performed: spraying water onto the surface of the second-type polishing disc. This setup improves the polishing effect and eliminates the need for polishing fluid, saving polishing costs.
[0037] For example, the aforementioned type II polishing disc is a diamond polishing disc. This type of polishing disc includes a substrate and a working layer. The substrate is, for example, a metal disc or a resin disc, and the working layer is a layered structure in which diamond abrasive (micro powder) is uniformly solidified (electroplated, resin-bonded, or metal-bonded) on the surface of the substrate. The polishing particle size of this type of polishing disc ranges from 0.4 micrometers to 0.6 micrometers. For example, the polishing particle size of this type of polishing disc is 0.4 micrometers; or 0.45 micrometers; or 0.5 micrometers; or 0.55 micrometers; or 0.6 micrometers. Preferably, the polishing particle size of this type of polishing disc is 0.5 micrometers.
[0038] Furthermore, the aforementioned third pre-pressure ranges from 30N to 40N. For example, the third pre-pressure is 30N; or 32N; or 35N; or 38N; or 40N. The aforementioned third preset duration ranges from 5 minutes to 10 minutes. For example, the third preset duration is 5 minutes; or 6 minutes; or 7.5 minutes; or 8 minutes; or 10 minutes. It is easy to understand that, since the smoothness of the outer surface of the composite metallographic specimen varies, those skilled in the art can flexibly set the specific values of the third pre-pressure and the third preset duration according to actual usage requirements; therefore, they will not be listed exhaustively here.
[0039] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for grinding and polishing metallographic specimens, characterized in that, A method for polishing composite metallographic specimens, comprising: Step S100: Use a grinding disc to perform metallographic grinding on the composite metallographic sample; Step S200: Perform the first metallographic polishing on the composite metallographic sample using a type of polishing pad; Step S300: Perform a second metallographic polishing on the composite metallographic sample using a type II polishing disc; The polishing precision of the second type of polishing pad is greater than that of the first type of polishing pad.
2. The metallographic sample polishing method according to claim 1, characterized in that, Step S100 includes: Step S110: Place the composite metallographic sample on the surface of the grinding disc; Step S120: Apply a first pre-pressure to the composite metallographic sample; the direction of the first pre-pressure is towards the surface of the grinding disc; Step S130: Rotate the grinding disc to perform metallographic grinding on the composite metallographic sample for a first preset time.
3. The metallographic sample polishing method according to claim 2, characterized in that, The grinding disc is a diamond particle grinding disc; the mesh size of the grinding disc ranges from 500 mesh to 700 mesh.
4. The metallographic sample polishing method according to claim 3, characterized in that, The first pre-pressure ranges from 7.5N to 12.5N; the first preset duration ranges from 5 minutes to 10 minutes.
5. The metallographic sample polishing method according to claim 1, characterized in that, Step S200 includes: Step S210: Place the metallographic sample of the composite material that has undergone metallographic grinding on the surface of the first type of polishing disc; Step S220: Apply a second pre-pressure to the composite metallographic sample; the direction of the second pre-pressure is towards the surface of the polishing disc. Step S230: Rotate the first type of polishing disc to perform the first metallographic polishing of the composite metallographic sample for a second preset time.
6. The metallographic sample polishing method according to claim 5, characterized in that, The polishing disc is a diamond polishing disc; the polishing particle size range of the polishing disc is 8 micrometers to 10 micrometers.
7. The metallographic sample polishing method according to claim 6, characterized in that, The second pre-pressure ranges from 30N to 40N; the second preset duration ranges from 5 minutes to 10 minutes.
8. The metallographic sample polishing method according to claim 1, characterized in that, Step S300 includes: Step S310: Place the composite metallographic sample that has undergone the first metallographic polishing onto the surface of the second type of polishing disc; Step S320: Apply a third pre-pressure to the composite metallographic sample; the direction of the third pre-pressure is towards the surface of the second type of polishing disk; Step S330: Rotate the second type of polishing disc to perform the second metallographic polishing of the composite metallographic sample for a third preset time.
9. The metallographic sample polishing method according to claim 8, characterized in that, The second type of polishing disc is a diamond polishing disc; the polishing particle size range of the second type of polishing disc is 0.4 micrometers to 0.6 micrometers.
10. The metallographic sample polishing method according to claim 9, characterized in that, The range of the third pre-pressure is 30N~40N; the range of the third preset duration is 5 minutes~10 minutes.