Universal high-efficiency metallographic phase preparation method for metal materials

Abstract

The invention relates to the field of metal materials, and discloses a universal high-efficiency metallographic preparation method for metal materials, which comprises the following steps of: (a) roughing a metal sample by using abrasive paper or a grinding disc; (b) finely grinding the metal sample by using a POS / POH (Poly Olefin Sulfonate / Poly Olefin Hydroxide) disc matched with a 9-micron (c) roughly polishing the sample by using weaving type polishing cloth matched with a grinding material with the particle size of 1-3 microns; and (d) finely polishing the metal sample by using polishing cloth matched with a 50nm-1mu m grinding material. The grinding pass can be reduced, the process is greatly shortened, the sample preparation efficiency is improved, batch sample preparation can be realized by matching with automatic equipment, and batch characterization is possible; the usage amount of abrasive paper can be greatly reduced, resources are saved, cost is reduced, and efficiency is improved; and the method has general applicability to metal material samples, and the high-quality metallographic sample can be prepared by only replacing suitable consumables according to the physicochemical properties of metal through four steps.

Description

Technical Field

[0001] This invention relates to the field of metallic materials, and more specifically to a method for preparing metallographic specimens of metallic materials. Background Technology

[0002] Metallographic analysis is an important tool for the design of metallic material composition, process control, quality inspection, and failure analysis. The surface quality of prepared metallographic samples is a crucial step in obtaining analytical results. With the rapid development of science and technology and the constant emergence of new metallic materials and processing techniques in the 21st century, high-throughput sample preparation and characterization—that is, batch sample preparation and analysis using automated equipment—have become essential means of verifying the quality and performance stability of new metallic materials and processing techniques.

[0003] However, the metallographic preparation of metallic materials still largely follows a process dating back over a century. The basic procedure involves progressively grinding with coarse to fine sandpaper in multiple passes to reduce the deformation layer caused during sampling and grinding, thus preparing for subsequent polishing. This grinding process requires frequent sandpaper replacements, and the lifespan of the sandpaper is significantly reduced, especially fine-grit sandpaper, which cannot be reused multiple times. This not only results in low efficiency but also substantial waste of materials. Traditional metallographic preparation methods for metallic materials can no longer meet the needs of high-throughput sample and characterization for modern new metallic materials and processing technologies. Summary of the Invention

[0004] This invention provides a highly efficient metallographic preparation method for metallic materials, with broad applicability. It is suitable for various metallic materials such as steel, copper and copper alloys, aluminum and aluminum alloys, and nickel and nickel alloys. High-quality metallographic samples can be prepared in four steps within a short time. The method features high efficiency, material savings, and the ability to achieve batch sample preparation when used with automated equipment. The steps are as follows:

[0005] Step (a) involves roughing the metal sample using sandpaper or a grinding wheel. The purpose of roughing is to grind the initial uneven surface of the metal sample to obtain a smooth sample surface, facilitating subsequent fine grinding operations. The type of sandpaper used for the initial grinding can be selected based on the characteristics of the sample. For example, for metal materials with a microhardness of 40HV~150HV or higher, sandpaper with a grit size of P1000~P2000 can be used for roughing; for metal materials with a microhardness of 150HV~500HV or higher, sandpaper with a grit size of P400~P800 can be used; for metal materials with a hardness exceeding 500HV, resin-bonded diamond grinding wheels and electroplated diamond grinding wheels, or grinding wheels made of alumina, silicon carbide, etc., with a grit size of P400~P800 can be used for roughing.

[0006] Step (b) involves using a POS / POH disc with 9µm abrasive to finely grind the metal sample. The POS disc is more suitable for soft metal samples, with a applicable hardness range of 40HV-1500HV; the POH disc is more suitable for hard metal samples, with an applicable hardness range of 150HV and above.

[0007] Step (c) Use a woven polishing cloth with 1-3µm abrasive particles to coarsely polish the sample. The type of polishing cloth can be selected according to the sample type. For example, YS-JP white fiber polishing cloth is suitable for coarse polishing of metals of all hardness types; SC-JP white silk polishing cloth and CS-JP blue rayon polishing cloth are more suitable for polishing coatings, non-ferrous metals, high-hardness ferrous metals and hard alloys.

[0008] Step (d) involves fine polishing the metal sample using a foamed rubber damping polishing cloth or flocked cloth with 50nm silica or alumina abrasive. The choice of polishing cloth depends on the sample type. For example, ZN cloth is suitable for fine polishing of alloys of all hardness levels, ET-JP white synthetic rayon polishing cloth is more suitable for fine polishing of soft non-ferrous metals, and SR-JP red synthetic fiber polishing cloth is more suitable for fine polishing of ferrous and hard metals.

[0009] Preferably, the four steps (a), (b), (c) and (d) above are not limited to grinding and polishing the sample using manual or automatic equipment.

[0010] Preferably, in steps (a), (b), (c) and (d), a manual grinding device is used, the grinding disc speed is set in the range of 100RPM to 1000RPM, and the grinding direction is not limited to clockwise or counterclockwise.

[0011] Preferably, in steps (a), (b), (c) and (d), an automatic grinding device is selected. The rotation speed of the upper clamping disc on the grinding device is set in the range of 5 RPM to 150 RPM, and the speed of the lower grinding disc is set in the range of 10 RPM to 600 RPM. The grinding direction of the upper and lower discs is not limited to clockwise or counterclockwise, and the direction of the two discs is not limited to the same direction or opposite directions.

[0012] Preferably, an automatic grinding device is used in steps (a), (b), (c) and (d), and the load applied to a single sample on the grinding device is set in the range of 1N to 60N.

[0013] In steps (a), (b), (c), and (d), the metallographic sample can be a mounted sample or a non-mounted sample. The mounted sample is not limited to hot mounting or cold mounting, and the shape of the mounting is not limited to cylindrical, rectangular, or irregular shapes. The non-mounted sample is not limited to using universal fixtures or custom fixtures.

[0014] In step (a), the coarse grinding consumables are not limited to sandpaper or grinding discs, wherein the sandpaper type is not limited to silicon carbide and alumina. The grinding disc type is not limited to resin-bonded diamond, electroplated diamond, alumina grinding discs, and silicon carbide grinding discs. To better avoid the formation of a deep deformation layer on the soft metal, the grinding process is not limited to applying wax or lubricant to the sandpaper surface.

[0015] Preferably, in step (b), the 9µm abrasive used is not limited to single-crystal diamond or polycrystalline diamond, and the abrasive state is not limited to paste, spray or suspension.

[0016] Preferably, in step (c), the 1-3 μm abrasive used is not limited to diamond or alumina, wherein the diamond is not limited to single-crystal diamond or polycrystalline diamond, and the abrasive state is not limited to paste, spray, or suspension. The abrasive particle size is not limited to single 1 μm or 3 μm, or a mixture of 1 μm and 3 μm, or intermediate particle sizes. The carrier of the suspension is not limited to water-based or anhydrous-based.

[0017] Preferably, in step (d), the 50nm~1µm abrasive is not limited to silicon dioxide and alumina, and the abrasive particle size is not limited to a single 50nm or 1µm, or a mixture of 50µm and 1µm, or intermediate particle sizes. The abrasive state is not limited to paste, spray, or suspension. The carrier of the suspension is not limited to water-based or anhydrous-based.

[0018] Preferably, in step (c) or (d), the polishing process is not limited to adding oxidants such as hydrogen peroxide or nitric acid alcohol to assist the polishing process.

[0019] In summary, the present invention has at least one of the following beneficial technical effects:

[0020] (1) It can reduce the number of grinding passes, greatly shorten the process, improve sample preparation efficiency, and enable batch sample preparation when combined with automated equipment, making batch characterization possible;

[0021] (2) It can greatly reduce the amount of sandpaper used, save resources, reduce costs and increase efficiency;

[0022] (3) It has universal applicability to metal material samples. Only by changing the appropriate consumables according to the physical and chemical properties of the metal can a high-quality metallographic sample be prepared in four steps. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 This is a simplified process flow diagram of the metallographic preparation method for metallic materials described in this invention;

[0025] Figure 2 The images show the polished and etched states of a 304 austenitic stainless steel sample taken under an optical microscope in Example 3 of this invention. The left image shows the polished state of the 304 austenitic stainless steel, and the right image shows the etched state.

[0026] Figure 3 The images shown are photographs of the polished and etched states of a 431 martensitic stainless steel sample taken under an optical microscope, according to Example 431 of this invention. The left image shows the polished state of the 431 martensitic stainless steel, and the right image shows the etched state.

[0027] Figure 4 The image shows a polished photograph of a metal-ceramic sample taken under an optical microscope, representing an embodiment of this invention.

[0028] Figure 5 These are photographs of industrial pure copper samples taken under an optical microscope in their polished and etched states, according to embodiments of this invention. The left image shows the polished state of the industrial pure copper, while the right image shows the etched state.

[0029] Figure 6 These are photographs of the H62 brass sample in the embodiment of this invention, taken under an optical microscope in both the polished and etched states. In the figures, the left image shows the H62 brass in the polished state, and the right image shows the etched state.

[0030] Figure 7 These are photographs of the polished and etched states of the 5-series aluminum alloy sample taken under an optical microscope according to Example 5 of this invention. In the figures, the left image shows the polished state of the 5-series aluminum alloy, and the right image shows the etched state.

[0031] Figure 8 The images show polished and etched TC4 titanium alloy samples taken under an optical microscope according to embodiments of this invention. The left image shows the polished TC4 titanium alloy, and the right image shows the etched TC4 titanium alloy. Detailed Implementation

[0032] 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.

[0033] The present invention will be further described in detail below with reference to the embodiments. These embodiments are merely preferred technical solutions of the present invention, but the implementation of the present invention is not limited thereto. It should be understood that the various metallographic preparation schemes for metallic materials described in the embodiments can be implemented in any of many ways, because the methods and embodiments disclosed in the present invention are not limited to any particular implementation. Furthermore, some aspects of the present invention can be used alone or in any suitable combination with other aspects disclosed in the present invention. The present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0034] Example 1: Method for preparing metallographic samples of 304 austenitic stainless steel

[0035] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan. Roughen the sample using P400-grit silicon carbide sandpaper, setting the pressure to 25N (pressure applied to a single sample, the same below). Set the rotation speed of the upper clamping pan (hereinafter referred to as the upper pan) to 80 RPM and the rotation speed of the lower grinding pan (hereinafter referred to as the upper pan) to 300 RPM. The grinding direction of the upper and lower pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal matrix.

[0036] Step 2: Replace the P400 grit sandpaper with a POS disc. During the grinding process, add 9µm polycrystalline diamond suspension to the drip system. The drip frequency is 1 second on and 20 seconds off. Set the upper disc speed to 50 RPM and the lower disc speed to 150 RPM. The grinding direction is the same, counter-clockwise. Set the pressure load to 25 N and the grinding time to 5 minutes.

[0037] Step 3: Replace the POS disk with a YS-JP white fiber polishing cloth. During the grinding process, add 3µm polycrystalline diamond suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk speed to 50 RPM and the lower disk speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 20N and the grinding time to 5 minutes.

[0038] Step 4: Replace the YS-JP white fiber polishing cloth with a ZN-JP rubber foam polishing cloth. Start the drip system and add 50nm silica polishing slurry during the polishing process. The drip frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 150 RPM. The polishing direction is the same direction, counter-clockwise. Set the pressure load to 20N and the polishing time to 3 minutes, including the last 20 seconds of water polishing.

[0039] Example 2: Method for preparing metallographic samples of 431 martensitic stainless steel

[0040] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan. Roughen the sample using P400-grit silicon carbide sandpaper, setting the pressure to 25N. Set the upper clamping pan speed to 80 RPM and the lower grinding pan speed to 300 RPM. The grinding direction of both pans should be the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the surface of the sample to be observed flat and exposing the new metal matrix.

[0041] Step 2: Replace the P400 grit sandpaper with a POS disc. During the grinding process, add 9µm polycrystalline diamond suspension. The dripping frequency is 1 second on and 20 seconds off. Set the upper disc speed to 50 RPM and the lower disc speed to 150 RPM. The grinding direction is reversed: upper disc clockwise, lower disc counterclockwise. Set the pressure load to 25N and the grinding time to 5 minutes.

[0042] Step 3: Replace the POS disk with an SC-JP white silk polishing cloth. During the grinding process, add 3µm polycrystalline diamond suspension using the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk rotation speed to 50 RPM and the lower disk rotation speed to 100 RPM. The grinding direction is reversed: upper disk clockwise, lower disk counterclockwise. Set the pressure load to 20N and the grinding time to 5 minutes.

[0043] Step 4: Replace the SC-JP white silk polishing cloth with a ZN-JP rubber foam polishing cloth. During the grinding process, add 50nm silica suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 20N and the grinding time to 3 minutes, including the last 20 seconds of water polishing.

[0044] Example 3: Method for preparing metal-ceramic metallographic samples

[0045] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan. Use a P400-mesh resin-bonded diamond grinding disc to roughen the sample. Set the pressure to 30N, the upper clamping disc speed to 50 RPM, and the lower grinding disc speed to 250 RPM. The grinding directions of the upper and lower discs are opposite: the upper disc clockwise, and the lower disc counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surfaces of the sample flat to expose the new metal matrix.

[0046] Step 2: Replace the P400-mesh resin-bonded diamond grinding disc with a POH disc. Start the drip system and add 9µm polycrystalline diamond suspension during the grinding process. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disc rotation speed to 50 RPM and the lower disc rotation speed to 150 RPM. The grinding direction is reversed: upper disc clockwise and lower disc counterclockwise. Set the pressure load to 30N and the grinding time to 5 minutes.

[0047] Step 3: Replace the POH disc with CS-JP blue rayon polishing cloth. Start the drip system and add 3µm polycrystalline diamond suspension during the grinding process. The drip frequency is 2 seconds on and 20 seconds off. Set the upper disc rotation speed to 50 RPM and the lower disc rotation speed to 150 RPM. The grinding direction is reversed: upper disc clockwise, lower disc counterclockwise. Set the pressure load to 25N and the grinding time to 5 minutes.

[0048] Step 4: Replace the CS-JP blue rayon polishing cloth with a ZN-JP rubber foam polishing cloth. During the grinding process, add 50nm silica suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 100 RPM. The grinding direction is counter-clockwise (upper plate clockwise, lower plate counter-clockwise). Set the pressure load to 20N and the grinding time to 3 minutes, including the last 20 seconds of water polishing.

[0049] Example 4: Method for preparing metallographic samples of industrial pure copper

[0050] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan. Roughen the sample using P400-grit silicon carbide sandpaper coated with paraffin wax for lubrication. Set the sample pressure to 20N, the upper clamping pan speed to 80RPM, and the lower grinding pan speed to 180RPM. The grinding direction of both pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal substrate.

[0051] Step 2: Replace the sandpaper with a POS disc. During the grinding process, add 9µm polycrystalline diamond suspension. The dripping frequency is 1 second on and 20 seconds off. Set the upper disc speed to 50 RPM and the lower disc speed to 150 RPM. The grinding direction is the same as the other side, counter-clockwise. Set the pressure load to 20N and the grinding time to 5 minutes.

[0052] Step 3: Replace the POS disk with a YS-JP white fiber polishing cloth. During the grinding process, add 3µm polycrystalline diamond suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk speed to 50 RPM and the lower disk speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 15N and the grinding time to 5 minutes.

[0053] Step 4: Replace the YS-JP white fiber polishing cloth with a ZN-JP rubber foam polishing cloth. During the grinding process, add a 50nm silica suspension (with a small amount of hydrogen peroxide solution). The dripping frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 15N and the grinding time to 5 minutes, including the last 20 seconds of water polishing.

[0054] Example 5: Preparation method of H62 brass metallographic sample

[0055] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan and roughen the sample using P400-grit silicon carbide sandpaper. Set the sample pressure to 20N, the upper clamping pan speed to 80RPM, and the lower grinding pan speed to 180RPM. The grinding direction of both pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal matrix.

[0056] Step 2: Replace the sandpaper with a POS disc. During the grinding process, add 9µm polycrystalline diamond suspension. The dripping frequency is 1 second on and 20 seconds off. Set the upper disc speed to 50 RPM and the lower disc speed to 150 RPM. The grinding direction is the same as the other side, counter-clockwise. Set the pressure load to 20N and the grinding time to 5 minutes.

[0057] Step 3: Replace the POS disk with a YS-JP white fiber polishing cloth. During the grinding process, add 3µm polycrystalline diamond suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk speed to 50 RPM and the lower disk speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 18N and the grinding time to 5 minutes.

[0058] Step 4: Replace the YS-JP white fiber polishing cloth with a ZN-JP rubber foam polishing cloth. During the grinding process, add a 50nm silica suspension (with a small amount of hydrogen peroxide solution). The dripping frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 18N and the grinding time to 4 minutes, including the last 20 seconds of water polishing.

[0059] Example 6: Method for preparing metallographic samples of 5-series aluminum alloys Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan and roughen the sample using P400-grit silicon carbide sandpaper. Set the sample pressure to 20N, the upper clamping pan speed to 80RPM, and the lower grinding pan speed to 180RPM. The grinding direction of both pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal matrix.

[0060] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan and roughen the sample using P400-grit silicon carbide sandpaper. Set the sample pressure to 20N, the upper clamping pan speed to 80RPM, and the lower grinding pan speed to 180RPM. The grinding direction of both pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal matrix.

[0061] Step 2: Replace the sandpaper with a POS disc. During the grinding process, add 9µm polycrystalline diamond suspension. The dripping frequency is 1 second on and 20 seconds off. Set the upper disc speed to 50 RPM and the lower disc speed to 150 RPM. The grinding direction is the same as the other side, counter-clockwise. Set the pressure load to 20N and the grinding time to 5 minutes.

[0062] Step 3: Replace the POS disk with SC-JP white silk polishing cloth. During the grinding process, add 1µm polycrystalline diamond suspension using the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk rotation speed to 50 RPM and the lower disk rotation speed to 150 RPM. The grinding direction is the same direction, counter-clockwise. Set the pressure load to 18N and the grinding time to 5 minutes.

[0063] Step 4: Replace the SC-JP white fiber polishing cloth with a ZN-JP rubber foam polishing cloth. During the grinding process, add 50nm alumina suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50 RPM and the lower plate speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 18N and the grinding time to 5 minutes, including the last 10 seconds of water polishing.

[0064] Example 7: Method for preparing metallographic samples of forged TC4 titanium alloy

[0065] Step 1: Using a Truly Alpha-610 automatic grinder, place the mounted sample into the clamping pan and roughen the sample using P400-grit silicon carbide sandpaper. Set the sample pressure to 25N, the upper clamping pan speed to 80RPM, and the lower grinding pan speed to 240RPM. The grinding direction of both pans is the same, counterclockwise. Add sufficient water to cool the sample during the grinding process to prevent overheating. This step only requires grinding the observed surface of the sample flat and exposing the new metal substrate.

[0066] Step 2: Replace the sandpaper with a POS disc, start the drip system and add 9µm polycrystalline diamond suspension during the grinding process. The drip frequency is 1 second on and 20 seconds off. Set the upper disc speed to 80RPM and the lower disc speed to 150RPM. The grinding direction is the same as the other side, which is counterclockwise. Set the pressure load to 20N and the grinding time to 5min.

[0067] Step 3: Replace the POS disk with a YS-JP white fiber polishing cloth. During the grinding process, add 3µm polycrystalline diamond suspension to the drip system. The drip frequency is 2 seconds on and 25 seconds off. Set the upper disk speed to 50 RPM and the lower disk speed to 150 RPM. The grinding direction is the same, but counter-clockwise. Set the pressure load to 18N and the grinding time to 5 minutes.

[0068] Step 4: Replace the YS-JP white fiber polishing cloth with the ZN-JP rubber foam polishing cloth. Start the drip system and add 50nm silica suspension during the grinding process. The drip frequency is 2 seconds on and 25 seconds off. Set the upper plate speed to 50RPM and the lower plate speed to 150RPM. The grinding direction is the same as the other side, which is counterclockwise. Set the pressure load to 18N and the grinding time to 5 minutes, including the last 20 seconds of water polishing.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A universal and highly efficient metallographic preparation method for metallic materials, characterized in that: include: Step (a) Roughen the metal sample using sandpaper or a grinding wheel; Step (b) Use a POS / POH disc with 9µm diamond abrasive to finely grind the metal sample; Step (c) Use a woven polishing cloth with 1~3um abrasive particles to coarsely polish the sample; Step (d) Use a polishing cloth with 50nm~1um abrasive to finely polish the metal sample.

2. The universal high-efficiency metallographic preparation method for metallic materials according to claim 1, characterized in that: The grinding and polishing methods in steps (a), (b), (c), and (d) include using a manual grinding machine and an automatic grinding machine.

3. The universal high-efficiency metallographic preparation method for metallic materials according to claim 1, characterized in that: In step (a), the sandpaper type includes alumina sandpaper and silicon carbide sandpaper, and the grinding disc type includes resin-bonded diamond, electroplated diamond, alumina grinding disc and silicon carbide grinding disc.

4. The universal high-efficiency metallographic preparation method for metallic materials according to claim 1, characterized in that: In step (b), the 9µm diamond abrasive includes single crystal and polycrystalline materials, and the state can be selected as suspension, spray and paste.

5. The universal high-efficiency metallographic preparation method for metallic materials according to claim 1, characterized in that: In step (c), the 1~3µm abrasive particles include diamond and alumina, wherein the diamond includes single crystal and polycrystalline materials, and the state includes suspension, spray and paste.

6. The universal high-efficiency metallographic preparation method for metallic materials according to claim 1, characterized in that: In step (d), the 50nm~1um abrasive particles include silicon dioxide and aluminum oxide, and the states include suspension, spray and paste.

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