Preparation method of metallographic specimen

Abstract

The invention relates to a preparation method of a metallographic specimen. The preparation method comprises the following steps: collecting a specimen; analyzing the sample to obtain material parameters of the sample; the collected material parameters are input into an abrasive selection system, and the optimal abrasive is output; grinding the sample by using an optimal grinding material to obtain a finely ground sample; polishing the sample subjected to fine grinding to obtain a polished sample; and carrying out multi-dimensional quality detection on the polished sample to judge whether the polished sample is qualified or not, and if the polished sample is not qualified, preparing again. According to the invention, sample material parameters are analyzed and input into the abrasive selection system, so that the optimal abrasive and preparation process matched with material characteristics can be accurately selected, the operation difference of human experience is remarkably reduced, the consistency of the surface quality and microscopic structure of the prepared metallographic sample is ensured, and the interpretation error caused by improper sample preparation is reduced.

Description

Technical Field

[0001] This invention relates to the field of sample preparation technology, and in particular to a method for preparing metallographic samples. Background Technology

[0002] Metallographic analysis is a crucial testing method in steel research and development. By observing and analyzing metallographic samples, information such as the microstructure, grain size, and phase composition of steel materials can be obtained, providing important basis for performance optimization, quality control, and new product development. However, currently, many factors affect the accuracy and reliability of metallographic sample preparation, leading to significant errors in the metallographic analysis results and failing to accurately reflect the true characteristics of steel materials.

[0003] Traditional grinding methods have certain shortcomings in abrasive selection, grinding process control, and quality inspection. For example, the selection of abrasive particle size often lacks scientific basis, leading to low grinding efficiency or severe damage to the sample surface; the control of pressure and rotation speed during grinding is not precise enough, making it difficult to guarantee the flatness and smoothness of the sample surface; in terms of quality inspection, it mainly relies on manual experience judgment, lacking objective and quantitative evaluation standards, which is prone to misjudgment. Therefore, there is an urgent need for a new method to ensure the accuracy and reliability of ground metallographic samples to meet the needs of high-precision metallographic analysis in the steel research and development field. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for preparing metallographic specimens.

[0005] A method for preparing a metallographic specimen, comprising:

[0006] Step 1: Collect the sample;

[0007] Step 2: Analyze the sample to obtain its material parameters;

[0008] Step 3: Input the collected material parameters into the abrasive selection system and output the optimal abrasive;

[0009] Step 4: Grind the sample using the optimal abrasive to obtain a finely ground sample.

[0010] Step 5: Polish the finely ground sample to obtain the polished sample.

[0011] Step 6: Perform multi-dimensional quality testing on the polished sample to determine whether the polished sample is qualified. If the polished sample is unqualified, it should be prepared again.

[0012] Preferably, step 3, which involves inputting the collected material parameters into the abrasive selection system and outputting the optimal abrasive, includes:

[0013] The chemical composition, hardness value, and microstructure of the sample are input into the abrasive selection system for comparison, and the optimal abrasive is output based on the comparison results.

[0014] Preferably, in step 4, a pressure sensor is used to detect the grinding pressure of the sample, and when the grinding pressure exceeds the preset range, the rotation speed of the grinding equipment is reduced; a surface roughness sensor is used to detect the surface roughness of the sample, and when the surface roughness of the sample does not meet the set requirements, the grinding time and the amount of abrasive supplied are adjusted.

[0015] Preferably, in step 6, the polished sample is subjected to quality testing using microstructure detection methods, surface quality detection methods, hardness detection methods, and chemical element analysis methods to determine whether the polished sample is qualified.

[0016] Preferably, during the microstructure detection process, image analysis software is used to quantitatively analyze the microscopic images of the sample to obtain data on grain size and phase content, which are then compared with standard spectra to determine whether the microstructure of the sample is normal.

[0017] Preferably, during the surface quality inspection process, the roughness and waviness of the sample surface are measured by a surface profilometer, the surface morphology information of the sample is obtained by an atomic force microscope, and the surface quality of the sample is evaluated according to the pre-set surface quality standards.

[0018] Preferably, during the hardness testing process, Rockwell hardness testers and Vickers hardness testers are used to test the hardness at different parts of the sample, and the hardness values ​​obtained from the tests are compared with the standard hardness range of the material. If the results do not meet the set comparison results, the hardness of the sample is unqualified.

[0019] Preferably, during the chemical elemental analysis process, an energy dispersive spectroscopy (EDS) analyzes the types and relative contents of elements on the sample surface, and an inductively coupled plasma mass spectrometer (ICP-MS) is used to perform quantitative analysis of trace elements in the sample. The analysis results are then compared with the original composition of the material to check whether there is elemental segregation or contamination in the sample.

[0020] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0021] This invention relates to a method for preparing metallographic specimens. Compared with the prior art, this invention analyzes the specimen material parameters and inputs them into an abrasive selection system, which can accurately select the optimal abrasive and preparation process that matches the material properties. This significantly reduces the differences in human experience and operation, ensures the surface quality and microstructure consistency of the prepared metallographic specimens, and reduces interpretation errors caused by improper sample preparation.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This invention provides a flowchart of a method for preparing metallographic specimens. Detailed Implementation

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," 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.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Please see Figure 1 A method for preparing a metallographic specimen, comprising:

[0029] Step 1: Collect the sample;

[0030] Based on the research objectives and requirements of the steel materials, samples should be taken from appropriate locations. During sampling, it is essential to ensure that the samples are representative and accurately reflect the overall characteristics of the material. For large steel products, wire cutting or electrical discharge machining (EDM) methods should be used for sampling to avoid damaging the sample's microstructure.

[0031] For small or irregularly shaped specimens, hot or cold mounting methods are used to embed them in suitable mounting materials. The mounting material must possess good hardness, wear resistance, and corrosion resistance to ensure specimen stability during the grinding process. During mounting, it is crucial to ensure a tight bond between the specimen and the mounting material, avoiding gaps or air bubbles.

[0032] Step 2: Analyze the sample to obtain its material parameters;

[0033] In step 2, the sampled steel material undergoes chemical composition analysis, hardness testing, and preliminary metallographic observation to obtain relevant parameters of the material. These parameters include the content of major elements such as carbon, silicon, manganese, phosphorus, and sulfur, the material's hardness value (such as Rockwell hardness, Brinell hardness, etc.), and the preliminary observed microstructure characteristics (such as grain size, phase composition, etc.).

[0034] Step 3: Input the collected material parameters into the abrasive selection system and output the optimal abrasive;

[0035] The collected parameters are input into the abrasive selection system. The system analyzes and calculates based on a pre-established abrasive selection model, and outputs the optimal abrasive selection scheme. Prepare the corresponding abrasives, such as sandpaper or polishing paste of different grit sizes, according to the system's recommended abrasive types and grit sizes.

[0036] Step 4: Grind the sample using the optimal abrasive to obtain a finely ground sample.

[0037] Step 4 includes:

[0038] Coarse grinding: The mounted sample is fixed on the grinding equipment, and the recommended coarse grinding abrasive (such as silicon carbide sandpaper with a grit size of 180-320 mesh) is selected for coarse grinding. During the coarse grinding process, various sensors on the grinding equipment are activated to collect grinding parameters and sample status data in real time. Based on the data collected by the sensors, the control system automatically adjusts the pressure, rotation speed, and abrasive supply of the grinding equipment to ensure the efficiency and stability of the coarse grinding process. The purpose of coarse grinding is to remove most of the machining allowance on the sample surface, so that the sample surface achieves preliminary flatness.

[0039] Fine grinding: After coarse grinding, clean the sample and replace it with a finer abrasive (such as 600-1200 mesh silicon carbide sandpaper) for fine grinding. During fine grinding, continue to monitor and adjust the grinding parameters in real time using sensors and a control system to further improve the smoothness and finish of the sample surface. During fine grinding, care should be taken to avoid leaving grinding marks from the coarse grinding stage to ensure a gradual improvement in the sample surface quality.

[0040] Fine grinding: After fine grinding, fine grinding is performed using a grinding paste with a particle size of 1500-2000 mesh (such as alumina grinding paste or diamond grinding paste). During fine grinding, the rotation speed and pressure of the grinding equipment should be further reduced to minimize damage to the sample surface and achieve a higher surface finish. During the fine grinding process, the surface roughness of the sample is monitored in real time using a surface roughness sensor. Fine grinding is stopped when the roughness reaches the predetermined accuracy requirement.

[0041] Step 5: Polish the finely ground sample to obtain the polished sample.

[0042] Polishing includes mechanical polishing and electrolytic polishing. Mechanical polishing involves selecting a suitable polishing cloth and polishing solution, and then mechanically polishing the finely ground sample. The polishing cloth should have a soft texture and good wear resistance, while the polishing solution should be selected based on the characteristics of the sample material (e.g., a polishing solution containing diamond micron powder). During mechanical polishing, the rotation speed of the polishing cloth and the flow rate of the polishing solution should be carefully controlled. Simultaneously, sensors should be used to monitor the temperature and pressure on the sample surface to prevent deformation or damage to the sample surface due to overheating or excessive pressure.

[0043] The electropolishing process is as follows: For some steel materials with extremely high surface quality requirements, electropolishing can be used as a further treatment on the basis of mechanical polishing. During electropolishing, appropriate electrolytes and electrolysis parameters (such as voltage, current density, and electrolysis time) are selected according to the composition and microstructure of the sample material. Electropolishing can remove the surface deformation layer generated during mechanical polishing, enabling the sample surface to achieve a higher degree of smoothness and flatness.

[0044] Step 6: Perform multi-dimensional quality testing on the polished sample to determine whether the polished sample is qualified. If the polished sample is unqualified, it should be prepared again.

[0045] In step 6, the present invention requires the use of microstructure detection methods, surface quality detection methods, hardness detection methods and chemical element analysis methods to perform quality detection on the polished sample in order to determine whether the polished sample is qualified.

[0046] Microstructure analysis: The polished sample is etched with a suitable etchant to reveal its microstructure. Then, the sample is observed and photographed using a metallographic microscope and an electron microscope. The acquired microscopic images are processed and analyzed using image analysis software to measure parameters such as grain size and phase content, and compared with standard spectra to determine whether the sample's microstructure is normal.

[0047] Surface quality inspection: The sample surface is scanned using a surface profilometer and atomic force microscope to obtain data such as surface roughness, waviness, and microstructure. The inspection results are evaluated according to pre-set surface quality standards to determine whether defects such as scratches, wear marks, or deformed layers exist on the sample surface. If the surface quality does not meet the requirements, the cause is analyzed, and the sample is re-ground and polished.

[0048] Hardness testing: Hardness tests are performed on different parts of the sample (e.g., the center, edges, etc.), with multiple tests for each part, and the average value is taken as the hardness value for that part. The obtained hardness value is compared with the standard hardness range of the material to determine whether the grinding process affected the hardness of the sample. If the hardness value is abnormal, the cause should be analyzed. It may be that overheating during the grinding process caused changes in the material structure, or that the sample was subjected to uneven pressure during the grinding process.

[0049] Chemical elemental analysis: The chemical elemental composition of the sample surface is analyzed using energy dispersive spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS). EDS can quickly detect the types and relative abundance of major elements on the sample surface, while ICP-MS enables precise quantitative analysis of trace elements. The analytical results are compared with the original composition of the material to check for elemental segregation or contamination. If abnormal elements are found, their source is analyzed; they may be due to impurities in the abrasive, polishing fluid, or environment that contaminated the sample surface during the grinding process.

[0050] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0051] (1) Improve grinding efficiency: The intelligent abrasive selection system can quickly and accurately select the most suitable abrasive, avoiding the problem of low grinding efficiency caused by improper abrasive selection. At the same time, the adaptive grinding process control method can automatically adjust the grinding parameters according to the real-time status of the sample, realizing an efficient and stable grinding process, which greatly shortens the grinding time.

[0052] (2) Improved sample quality: The multi-dimensional quality inspection system comprehensively tests the samples from multiple aspects, including microstructure, surface quality, hardness, and chemical element analysis, ensuring the accuracy and reliability of the samples. By strictly controlling various parameters in the grinding process, defects such as scratches, wear marks, and deformation layers on the sample surface are reduced, improving the surface quality and clarity of the microstructure of the samples, and providing more accurate images and data for metallographic analysis.

[0053] (3) Enhanced reliability of analytical results: Metallographic samples prepared using the method of this invention can accurately reflect the microstructure and performance characteristics of steel materials, reducing deviations in metallographic analysis results caused by sample preparation errors. This enables steel R&D personnel to optimize material properties and develop new products based on more accurate metallographic analysis results, improving R&D efficiency and success rate, and reducing R&D costs.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a metallographic specimen, characterized in that, include: Step 1: Collect the sample; Step 2: Analyze the sample to obtain its material parameters; Step 3: Input the collected material parameters into the abrasive selection system and output the optimal abrasive; Step 4: Grind the sample using the optimal abrasive to obtain a finely ground sample. Step 5: Polish the finely ground sample to obtain the polished sample. Step 6: Perform multi-dimensional quality testing on the polished sample to determine whether the polished sample is qualified. If the polished sample is unqualified, it should be prepared again.

2. The method for preparing a metallographic specimen according to claim 1, characterized in that, Step 3: Input the collected material parameters into the abrasive selection system and output the optimal abrasive, including: The chemical composition, hardness value, and microstructure of the sample are input into the abrasive selection system for comparison, and the optimal abrasive is output based on the comparison results.

3. The method for preparing a metallographic specimen according to claim 2, characterized in that, In step 4, a pressure sensor is used to detect the grinding pressure of the sample. When the grinding pressure exceeds the preset range, the rotation speed of the grinding equipment is reduced. A surface roughness sensor is used to detect the surface roughness of the sample. When the surface roughness of the sample does not meet the set requirements, the grinding time and the amount of abrasive supplied are adjusted.

4. The method for preparing a metallographic specimen according to claim 1, characterized in that, In step 6, the polished sample is subjected to quality testing using microstructure detection methods, surface quality detection methods, hardness detection methods, and chemical element analysis methods to determine whether the polished sample is qualified.

5. The method for preparing a metallographic specimen according to claim 4, characterized in that, During the microstructure detection process, image analysis software is used to quantitatively analyze the microscopic images of the sample to obtain data on grain size and phase content, which are then compared with standard spectra to determine whether the microstructure of the sample is normal.

6. The method for preparing a metallographic specimen according to claim 4, characterized in that, In the surface quality inspection process, the roughness and waviness of the sample surface are measured by a surface profilometer, the surface morphology information of the sample is obtained by an atomic force microscope, and the surface quality of the sample is evaluated according to the pre-set surface quality standards.

7. The method for preparing a metallographic specimen according to claim 4, characterized in that, During the hardness testing process, Rockwell hardness testers and Vickers hardness testers are used to test the hardness at different parts of the sample, and the hardness values ​​obtained are compared with the standard hardness range of the material. If the results do not meet the set comparison results, the hardness of the sample is unqualified.

8. The method for preparing a metallographic specimen according to claim 4, characterized in that, In the process of chemical elemental analysis, energy dispersive spectroscopy is used to analyze the types and relative contents of elements on the sample surface, and inductively coupled plasma mass spectrometry is used to perform quantitative analysis of trace elements in the sample. The analysis results are compared with the original composition of the material to check whether there is elemental segregation or contamination in the sample.

Images