Preparation method of non-oriented silicon steel micro-texture sample

Abstract

The invention discloses a preparation method of a non-oriented silicon steel micro-texture sample, and belongs to the field of sports equipment. The method comprises the following steps: (1) coarse grinding; (2) fine grinding; (3) polishing; (4) corrosion: the corrosion time is properly adjusted according to chemical components, the preparation of a non-oriented silicon steel microstructure sample is completed by using a 4% nitric acid alcohol solution, and the microstructure sample with the resolution rate of 95% or above is obtained; wherein when the content of Si is 0.75-0.95%, the corrosion time is not less than 25 seconds. By controlling the sample preparation steps, the corrosion mode, the corrosion time and the like, rapid preparation of the non-oriented silicon steel microstructure sample is achieved, and the texture evolution rule research efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of sports equipment, and in particular relates to a method for preparing a non-oriented silicon steel micro-texture sample. Background Art

[0002] Non-oriented silicon steel is a soft magnetic material with excellent performance. It is widely used in household appliances, industrial motors, wind power generation, new energy vehicles, humanoid robots, drones and other industries. With the continuous improvement of energy efficiency levels, the requirements for the performance of non-oriented silicon steel in various fields are constantly increasing, making it continue to develop in the direction of high grade and thin specifications. The performance of non-oriented silicon steel is affected by chemical composition, grain size and texture, among which texture is the key factor determining performance. In the research and development of non-oriented silicon steel, X-ray diffractometers and EBSD in SEM are usually used to detect macro texture and micro texture respectively, and study the influence of different production processes on the evolution law of texture of non-oriented silicon steel. Therefore, preparing good texture samples is very important for product research and development. The preparation process of micro texture of non-oriented silicon steel usually includes steps such as coarse grinding, fine grinding, polishing and corrosion. The preparation quality of each step will affect the accuracy of texture detection results. Through research, the present invention simplifies the preparation process of micro texture samples of non-oriented silicon steel and improves work efficiency.

[0003] Currently, application number 202211144831.7 discloses a method for displaying the microstructure of a stretched and flattened annealed sample of oriented silicon steel, focusing on the process for observing the microstructure of such a sample. The invention details the sample preparation steps and the method for discharging the etching solution. Through the steps of sampling, sample pretreatment, etching, scale preparation, and microstructure photography, a microstructure of a stretched and flattened annealed sample of oriented silicon steel with clear grain boundaries is obtained. This method provides guidance for the preparation of samples for microstructure observation of oriented silicon steel.

[0004] Application No. 202410119195.5 discloses a solution and method for use in microstructure observation and magnetic property testing of grain-oriented silicon steel in the high-temperature annealed state. The solution also details a method for preparing a solution that inhibits rapid surface oxidation of grain-oriented silicon steel after removal of a magnesium silicate substrate. The invention focuses on controlling the mass fractions of nanoscale colloidal silica, alkali, sodium hexametaphosphate, and distilled water in the solution to achieve a sealing layer with high transparency, excellent oxidation resistance, and no effect on collective magnetic property measurements. This facilitates the long-term preservation of grain-oriented silicon steel samples and enables continuous microstructure observation.

[0005] Application No. 201510664987.1 discloses an etchant and etching method for revealing the dendritic structure of solidified medium- and high-grade non-oriented silicon steel, focusing on the preparation and use of the etchant. This document details the ratio of the etchant's components, the functions of each component, and precautions for using the etchant during the etching process, including the etchant's state, sample placement, and post-etch sample treatment. This document provides a reference for preparing samples with clear dendritic structure from medium- and high-grade non-oriented silicon steel ingots.

[0006] Non-oriented silicon steel, a soft magnetic material with excellent performance, is a core material for the manufacture of various motors and electrical appliances, and its consumption is considerable. Texture is a key factor influencing its performance, and its type directly determines the properties of the finished product. Therefore, studying the influence of process parameters on the evolution of texture type is essential for the development of high-performance non-oriented silicon steel. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preparing micro-texture samples of non-oriented silicon steel, improve the preparation efficiency of micro-texture samples, greatly improve the progress of product research and development, determine the optimal sample preparation method through experiments, and lay an effective foundation for the research and development of non-oriented silicon steel products.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for preparing a non-oriented silicon steel microtexture sample, comprising the following steps:

[0010] (1) Coarse grinding;

[0011] (2) fine grinding;

[0012] (3) Polishing;

[0013] (4) Corrosion:

[0014] By appropriately adjusting the corrosion time according to the chemical composition, the microtexture sample of non-oriented silicon steel can be prepared using 4% nitric acid alcohol solution, and the microtexture sample with a resolution of more than 95% can be obtained; when the Si content is 0.75-0.95%, the corrosion time is not less than 25s.

[0015] Furthermore, the step (1) of rough grinding specifically includes: first, using a belt sander to grind the test surface of the sample into a flat surface, removing surface burrs and other obstacles that affect sample preparation. Then, using 120#, 240#, and 320# sandpaper to rough grind the test surface of the sample, rotating the sample 90° each time a sandpaper type is changed to remove the coarse scratches left by the belt sander.

[0016] Furthermore, the step (2) fine grinding specifically includes: using sandpaper of types 500#, 1000#, 1200#, 1500# and 2000# to fine grind the coarse ground sample, and the number of fine grinding passes can be appropriately increased or decreased according to the hardness of the sample. Each time a sandpaper type is changed, the sample is rotated 90° until the sample is bright and has no obvious or relatively obvious scratches.

[0017] Furthermore, the polishing step (3) specifically includes: polishing the coarsely ground and finely ground sample using a polishing machine, and maintaining the sample level during the polishing process to prevent the sample from being ground into facets that affect the subsequent texture detection. The sample detection surface is polished to a mirror surface by polishing, and the sample surface is observed using a metallographic microscope in polarized light mode during the polishing process until the stress on the sample surface is completely eliminated, completing the polishing process.

[0018] Furthermore, when the Si content is 0.75-0.95%, the corrosion time is 25s.

[0019] Furthermore, when the Si content is 0.75-0.95%, the corrosion time is 30s.

[0020] Furthermore, the method obtained a microtexture sample with a resolution of 95%.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The present invention realizes the rapid preparation of non-oriented silicon steel microtexture samples by controlling the sample preparation steps, corrosion method, corrosion time, etc., and improves the efficiency of texture evolution law research. DETAILED DESCRIPTION

[0023] A method for preparing a non-oriented silicon steel microtexture sample comprises the following steps:

[0024] (1) Coarse grinding

[0025] First, use a belt sander to grind the test surface of the sample into a flat surface, removing any surface burrs or other obstacles that could hinder sample preparation. Next, use 120#, 240#, and 320# sandpaper to coarsely grind the test surface. Each time you change sandpaper, rotate the sample 90° to remove any coarse scratches left by the belt sander.

[0026] (2) Fine grinding

[0027] Use 500#, 1000#, 1200#, 1500# and 2000# sandpaper to fine-grind the coarse-ground samples. The number of fine-grinding passes can be appropriately increased or decreased according to the hardness of the sample. Each time a new type of sandpaper is changed, the sample is rotated 90° until the sample is bright and has no obvious or relatively obvious scratches.

[0028] (3) Polishing

[0029] Polish the coarsely and finely ground samples using a polishing machine. Keep the sample level during the polishing process to prevent faceting that could affect subsequent texture testing. Polish the sample's test surface to a mirror finish. Observe the sample surface using a metallographic microscope in polarized light mode until surface stress is completely eliminated, completing the polishing process.

[0030] (4) Corrosion

[0031] To better visualize the sample's diffraction pattern, the sample needs to be etched. Electrolytic etching is typically used, which is cumbersome and inefficient. This invention, through trial and error, adjusts the etching time according to the chemical composition, achieving the preparation of non-oriented silicon steel microtexture samples using a 4% nitric acid alcohol solution, resulting in a microtexture sample with a resolution of over 95%.

[0032] In order to better explain the present invention, the main contents of the present invention are further illustrated below in conjunction with specific embodiments.

[0033] Table 1 shows different etching methods and etching times of Examples 1-5 and Comparative Example 1, and Table 2 shows the resolution of samples of Examples 1-5 and Comparative Example 1.

[0034] Table 1 Examples of the present invention and comparative examples

[0035]

[0036] Table 2 Resolution of various embodiments of the present invention and comparative examples

[0037] Resolution % Comparative Example 1 98 Example 1 88 Example 2 95 Example 3 93 Example 4 89 Example 5 91

[0038] Table 2 shows that when electropolishing the sample, the resolution rate is very high, approaching 100%. Under the same chemical composition, using 4% nitric acid solution for the same time, the resolution rate is lower, only 88%. Prolonging the etching time can effectively improve the resolution rate. Furthermore, as the Si content increases, the etching time needs to be extended accordingly to ensure effective etching and achieve a high resolution rate.

[0039] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for preparing a non-oriented silicon steel microtexture sample, characterized in that: The steps include: (1) Coarse grinding; (2) fine grinding; (3) Polishing; (4) Corrosion: By appropriately adjusting the corrosion time according to the chemical composition, the microtexture sample of non-oriented silicon steel can be prepared using 4% nitric acid alcohol solution, and the microtexture sample with a resolution of more than 95% can be obtained; when the Si content is 0.75-0.95%, the corrosion time is not less than 25s.

2. The method for preparing a non-oriented silicon steel microtexture sample according to claim 1, wherein: The step (1) of rough grinding specifically includes: first, using a belt sander to grind the test surface of the sample into a flat surface, removing surface burrs and other obstacles that may affect sample preparation. Then, using 120#, 240#, and 320# sandpaper to rough grind the test surface of the sample, rotating the sample 90° each time a different sandpaper type is used to remove coarse scratches left by the belt sander.

3. The method for preparing a non-oriented silicon steel microtexture sample according to claim 1, wherein: The step (2) fine grinding specifically includes: using sandpaper of types 500#, 1000#, 1200#, 1500# and 2000# to fine grind the coarse ground sample, and the number of fine grinding passes can be appropriately increased or decreased according to the hardness of the sample. Each time a sandpaper type is changed, the sample is rotated 90° until the sample is bright and has no obvious or relatively obvious scratches.

4. The method for preparing a non-oriented silicon steel microtexture sample according to claim 1, wherein: The polishing step (3) specifically includes: polishing the coarsely ground and finely ground sample using a polishing machine, and the sample must be kept level during the polishing process to prevent the sample from being ground into facets that affect the subsequent texture detection. The sample detection surface is polished to a mirror surface by polishing, and the sample surface is observed using a metallographic microscope in polarized mode during the polishing process until the stress on the sample surface is completely eliminated, thus completing the polishing process.

5. The method for preparing a non-oriented silicon steel microtexture sample according to claim 1, wherein: When the Si content is 0.75-0.95%, the corrosion time is 25s.

6. The method for preparing a non-oriented silicon steel microtexture sample according to claim 1, wherein: When the Si content is 0.75-0.95%, the corrosion time is 30s.

7. The method for preparing a non-oriented silicon steel microtexture sample according to claim 5, wherein: This method obtains microtexture samples with a resolution of 95%.

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