In-plane non-oriented electromagnetic metal plate and its manufacturing method

Abstract

To provide an in-plane non-directional electromagnetic metal plate and a manufacturing method thereof with controlled crystal orientation and excellent magnetic properties.SOLUTION: The crystal orientation of an in-plane non-directional electromagnetic metal plate is oriented in the plane of the surface of a metal plate. In the in-plane non-directional electromagnetic metal plate, the <001> direction of a crystal may be aligned substantially parallel to the plate surface normal direction. In a manufacturing method of an in-plane non-directional electromagnetic metal plate, a projection material is projected onto the surface of a metal plate to perform surface processing.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an in-plane non-oriented electromagnetic metal plate and a method for manufacturing the same. [Background technology]

[0002] Conventional electrical steel sheets are manufactured by combining rolling and heat treatment, and by strictly controlling the conditions for these processes to orient the crystal orientation and improve the magnetic properties. For example, Patent Document 1 discloses a method for manufacturing an iron sheet, which involves a step of rolling a cast material and a step of heating (heat treating) the rolled material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Application No. 2015-32147 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the frequency of AC power applied to electrical steel sheets has been increasing, making the magnetic properties near the surface of the sheet particularly important. However, because the crystal orientation of conventional electrical steel sheets is controlled not only near the surface but also throughout the entire sheet, including the interior, there is still room for improvement in the magnetic properties near the surface.

[0005] Furthermore, with conventional electrical steel sheets, the management of each process in their manufacturing is complex. For example, the heat treatment process requires heating to a high temperature (e.g., 1300°C) and holding the temperature for a long period of time (e.g., 100 hours), which requires a lot of energy for manufacturing. Furthermore, in order to improve the magnetic properties, the composition must be strictly controlled, making it difficult to easily manufacture electrical steel sheets.

[0006] The present invention provides an in-plane non-oriented electromagnetic metal sheet having controlled crystal orientation and excellent magnetic properties, and a method for producing the same. [Means for solving the problem]

[0007] In an in-plane non-oriented electromagnetic metal plate according to one embodiment of the present invention, the crystal orientation is oriented within the surface of the metal plate.

[0008] The in-plane non-oriented electromagnetic metal plate has a crystal orientation controlled to a predetermined direction within the surface of the metal plate, which improves magnetic properties. This makes it suitable for use as an electromagnetic metal plate for motor cores, reactor materials, etc.

[0009] Furthermore, the in-plane non-oriented electromagnetic metal sheet has a controlled crystal orientation near the surface of the metal sheet, which results in superior magnetic properties at high frequencies, compared to conventional electromagnetic steel sheets in which the crystal orientation is controlled not only on the surface but throughout the entire sheet by rolling and heat treatment.

[0010] In the above-mentioned in-plane non-oriented electromagnetic metal plate, <001> The direction may be aligned approximately parallel to the normal direction of the plate surface. In this case, the easy axis of magnetization of the crystal <001> The direction can be controlled to be approximately parallel to a predetermined direction, that is, the normal direction to the plate surface (the direction perpendicular to the surface of the metal plate), thereby improving the magnetic properties.

[0011] In addition, when measuring the crystal orientation distribution within the surface of a metal plate, <001> The crystal orientation distribution may have at least one peak detected between 0° and 15° from the normal direction of the plate, which has a higher intensity than the group of peaks formed between 75° and 105° from the normal direction of the plate. In this case, the easy axis of magnetization of the crystal is <001> The direction can be controlled to a predetermined direction, thereby improving the magnetic properties.

[0012] In addition, in the above measurement, <111> The crystal orientation distribution may have peaks formed between 0° and 15° from the normal direction to the plate surface and between 39° and 85° from the normal direction to the plate surface. In this case, the hard axis of magnetization of the crystal is <111> The direction can be controlled to a predetermined direction, thereby improving the magnetic properties.

[0013] Furthermore, the crystal orientation may be oriented in at least a portion of the region from the surface of the metal plate to a depth of 100 μm, including the surface of the metal plate. In this case, the crystal orientation can be controlled in the region near the surface of the metal plate, thereby improving the magnetic properties.

[0014] The metal material constituting the metal plate may be a steel material whose crystal structure is a body-centered cubic lattice structure or a body-centered tetragonal lattice structure. In this case, the magnetic properties can be further improved. The metal plate can also be used as an electromagnetic steel plate for motor cores, reactor materials, etc.

[0015] The steel material may be pure iron, which can further improve the magnetic properties.

[0016] Another aspect of the present invention is a method for manufacturing an in-plane non-oriented electromagnetic metal plate, in which the crystal orientation is oriented within the surface of the metal plate, and a surface processing treatment is performed by projecting a projection material onto the surface of the metal plate.

[0017] According to the above-described method for manufacturing an in-plane non-oriented electromagnetic metal sheet, the crystal orientation can be easily controlled in a predetermined direction within the surface of the metal sheet by projecting a shot material onto the surface of the metal sheet to perform a surface processing treatment. Therefore, compared to conventional electromagnetic steel sheets, which require rolling and heat treatment to control the crystal orientation, complicated process management is not required. Furthermore, there is no need for high-temperature, long-term heat treatment, which reduces manufacturing energy. This allows for easy production of an electromagnetic metal sheet with controlled crystal orientation and excellent magnetic properties.

[0018] Furthermore, the in-plane non-oriented electromagnetic metal sheet manufactured by the above manufacturing method has a controlled crystal orientation near the surface of the metal sheet, which results in superior magnetic properties at high frequencies. This results in superior magnetic properties at high frequencies compared to conventional electromagnetic steel sheets, in which rolling and heat treatment are performed to control the crystal orientation not only on the surface but throughout the entire sheet.

[0019] In the method for manufacturing the in-plane non-oriented electromagnetic metal plate, the crystalline orientation of the surface of the metal plate can be controlled by adjusting at least one of the blast pressure and the blast time of the blast material in the surface processing treatment. In this case, the crystalline orientation of the surface of the metal plate can be controlled with high precision.

[0020] Furthermore, after the surface processing, a heat treatment may be further carried out, in which case the crystal orientation within the surface of the metal plate can be controlled with high precision.

[0021] Furthermore, before the surface treatment, a lubricant may be applied to at least the area of ​​the surface of the metal plate to be treated. In this case, friction between the surface of the metal plate and the shot material projected onto the surface of the metal plate during the surface treatment is reduced, allowing for precise control of the crystal orientation within the surface of the metal plate.

[0022] The metal material constituting the metal plate may be a steel material whose crystal structure is a body-centered cubic lattice structure or a body-centered tetragonal lattice structure. In this case, it is possible to manufacture an electrical steel sheet with superior magnetic properties. It is also possible to manufacture an electrical steel sheet that is effective for applications such as motor cores and reactor materials.

[0023] The steel material may also be pure iron, in which case an electrical steel sheet with even better magnetic properties can be produced. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a scanning electron microscope (SEM) photograph of the sample. [Figure 2]This is an inverse pole figure (IPF) map of the sample obtained by electron backscatter diffraction (EBSD) method. [Figure 3] The (001) and (111) pole figures of the sample were obtained by electron backscatter diffraction (EBSD) analysis. [Figure 4] The (001) and (111) pole figures of the sample were obtained by X-ray diffraction (XRD). [Figure 5] 1 is a scanning electron microscope (SEM) photograph of the sample. [Figure 6] This is an inverse pole figure (IPF) map of the sample obtained by electron backscatter diffraction (EBSD) method. [Figure 7] 1 is a scanning electron microscope (SEM) photograph of the sample. [Figure 8] This is an inverse pole figure (IPF) map of the sample obtained by electron backscatter diffraction (EBSD) method. [Figure 9] The (001) and (111) pole figures of the sample were obtained by electron backscatter diffraction (EBSD) analysis. [Figure 10] The (001) and (111) pole figures of the sample were obtained by X-ray diffraction (XRD). [Figure 11] 1 is a scanning electron microscope (SEM) photograph of the sample. [Figure 12] This is an inverse pole figure (IPF) map of the sample obtained by electron backscatter diffraction (EBSD) method. [Figure 13] The (001) and (111) pole figures of the sample were obtained by electron backscatter diffraction (EBSD) analysis. [Figure 14] The (001) and (111) pole figures of the sample were obtained by X-ray diffraction (XRD). [Figure 15] The (001) and (111) pole figures of the sample were obtained by X-ray diffraction (XRD). [Figure 16]The (001) and (111) pole figures of the sample were obtained by electron backscatter diffraction (EBSD) analysis. [Figure 17] The (001) and (111) pole figures of the sample were obtained by electron backscatter diffraction (EBSD) analysis. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described.

[0026] [In-plane non-directional electromagnetic metal plate] First, the in-plane non-oriented electromagnetic metal plate will be described. In-plane non-oriented electromagnetic metal plates have crystal orientation oriented within the surface plane of the metal plate.

[0027] The in-plane non-oriented electromagnetic metal plate can be made of a plate-shaped metal material. Examples of the metal material that can be used include pure iron and iron alloys. Examples of the iron alloy that can be used include carbon steel and iron-silicon alloys. In addition, metals other than iron, such as copper, and alloys thereof, can also be used as the metal material.

[0028] In an in-plane non-oriented electromagnetic metal plate, the in-plane of the surface of the metal plate where the crystal orientation is oriented refers to the surface layer of the metal plate (the area near the surface), for example, the area from the surface of the metal plate to a depth of 100 μm.

[0029] In an in-plane non-oriented electromagnetic metal plate, the alignment of the crystal orientation within the surface of the metal plate can be confirmed, for example, by measuring the crystal orientation distribution within the surface of the metal plate. The crystal orientation distribution can be measured, for example, by electron backscatter diffraction (EBSD), which is suitable for measuring a local area, or by X-ray diffraction (XRD), which is suitable for measuring a wide area.

[0030] In a plane-oriented non-oriented electromagnetic metal plate, the crystal <001> The direction may be aligned approximately parallel to the normal direction of the plate surface. <001> This means that the direction is controlled to an inclination of 0° to 15° relative to the normal direction of the plate surface.

[0031] In measuring the crystal orientation distribution within the surface of a metal plate, <001> The crystal orientation distribution may have at least one peak detected between 0° and 15° from the normal direction to the plate surface, the peak having a higher intensity than the group of peaks formed between 75° and 105° from the normal direction to the plate surface. <001> The crystals whose orientation is between 0° and 15° from the normal to the plate surface are different from other <001> Therefore, the crystal orientation is between 0° and 15° from the normal to the plate surface and between 75° and 105° from the normal to the plate surface. <001> A peak in the direction is formed.

[0032] In the above measurement, the crystal <111> The crystal orientation distribution may have peak groups detected in the direction between 0° and 15° from the normal to the plate surface and between 39° and 85° from the normal to the plate surface. <111> Crystals whose orientation is between 0° and 15° from the normal to the plate surface are <111> The direction is between 55° and 85° from the normal direction of the plate surface. <001> The crystals whose orientation is 0° to 15° from the normal direction of the plate surface are <111> Therefore, the crystal orientation is between 0° and 15° from the normal to the plate surface and between 39° and 85° from the normal to the plate surface. <111> A peak in the direction is formed.

[0033] In an in-plane non-oriented electromagnetic metal plate, the crystal orientation may be oriented in at least a portion of a region extending from the surface of the metal plate to a depth of 100 μm, the region including the surface of the metal plate. Here, the at least a portion of the region extending from the surface of the metal plate to a depth of 100 μm may be, for example, a region extending from the surface of the metal plate to a depth of 10 μm, a region extending from the surface of the metal plate to a depth of 50 μm, or a region extending from the surface of the metal plate to a depth of 100 μm.

[0034] [Method of manufacturing in-plane non-oriented electromagnetic metal sheet] Next, a method for manufacturing an in-plane non-oriented electromagnetic metal plate will be described. The method for manufacturing an in-plane non-oriented electromagnetic metal plate involves projecting a projection material onto the surface of the metal plate to perform a surface processing treatment.

[0035] As the surface processing treatment, a method can be used in which a projection material is projected onto the surface of a metal plate and the projection material is caused to collide with the surface of the metal plate at high speed to perform surface processing, and for example, shot peening, shot blasting, etc. can be used.

[0036] The material of the shot material used in the surface treatment can be appropriately selected depending on the material of the metal plate to be shot and hit, etc. For example, when a steel material is used as the metal material constituting the metal plate, hard particles such as zircon particles can be used as the shot material.

[0037] The conditions for the surface processing treatment can be adjusted as appropriate. For example, the projection pressure of the projection material, the projection time, the distance between the surface of the metal plate and the projection nozzle that projects the projection material, etc. can be adjusted. By adjusting the projection pressure and projection time of the projection material, the orientation state of the crystal orientation within the surface of the metal plate can be controlled.

[0038] Furthermore, after the above-mentioned surface processing treatment, a heat treatment may be further performed. In the heat treatment, the metal plate is heated to a predetermined temperature and maintained for a predetermined time. The conditions of the heat treatment can be appropriately adjusted, for example, the heating temperature, the maintenance time, etc. By adjusting the conditions of the heat treatment, the crystal orientation within the surface of the metal plate can be precisely controlled.

[0039] The heating temperature in the heat treatment can be, for example, 400°C to 800°C, and particularly 500°C to 650°C. This eliminates the need for high-temperature heating compared to conventional electrical steel sheet manufacturing, allowing for a significant reduction in manufacturing energy. Furthermore, the crystal orientation within the surface of the metal sheet can be precisely controlled.

[0040] The holding time (heating time) in the heat treatment can be, for example, 0.5 to 10 hours. The holding time in the heat treatment can be adjusted appropriately depending on the material of the metal plate, etc., in order to precisely control the crystal orientation in the plane of the surface of the metal plate.

[0041] Furthermore, before the surface treatment, a lubricant may be applied to at least the area (processing area) of the surface of the metal plate where the surface treatment is to be performed. Examples of the lubricant that can be applied to the processing area of ​​the surface of the metal plate include boron nitride (hexagonal boron nitride, etc.), molybdenum disulfide, graphite, and mineral oil.

[0042] The present invention will be described below with reference to examples, although the present invention is not limited to these examples.

[0043] (Example) <Crystal orientation distribution before shot peening> First, a sample was prepared. Specifically, a 15 mm × 15 mm sample piece was cut out from a commercially available rolled pure Fe sheet with a thickness of 1.5 mm to obtain a metal plate made of pure Fe. The metal plate was then annealed at 550°C for 1 hour. In this way, an annealed sample (sample A1) was prepared before shot peening.

[0044] Next, the surface of the sample (sample A1) was observed using a scanning electron microscope (JIB4600-F, manufactured by JEOL Ltd.). Figure 1 shows a scanning electron microscope (SEM) photograph of the sample surface. The SEM photograph in Figure 1 shows that the sample before shot peening has equiaxed crystal grains.

[0045] Next, the crystal orientation distribution on the surface of the sample (sample A1) was analyzed using a scanning electron microscope equipped with an electron backscatter diffraction (EBSD) detector (TSL, OIM Data Collection 7). Figure 2 is an inverse pole figure (IPF) map obtained by EBSD, showing the crystal orientation distribution on the sample surface. The IPF map in Figure 2 also shows that the sample before shot peening had equiaxed crystal grains.

[0046] Figure 3 shows the crystal structure of the specimen surface obtained by EBSD. <001> Direction and <111> The (001) and (111) pole figures show the crystal orientation distribution in the direction. From the pole figures in Figure 3, it can be seen that the crystal orientation distribution in the plane of the sample surface is <001> Direction and <111> It can be seen that there is no orientation distribution in either direction, and that the orientation is random.

[0047] Next, the surface of the sample (sample A1) was analyzed using an X-ray diffractometer (Rigaku Corporation, SmartLabo). Figure 4 shows the crystal structure of the sample surface obtained by X-ray diffraction (XRD). <001> Direction and <111> The (001) and (111) pole figures show the crystal orientation distribution in the direction. The XRD method can obtain measurement results over a wider range than the EBSD method mentioned above. In the pole figure of Figure 3 obtained by measuring a local area using the EBSD method, the crystal orientation distribution can be seen. <001> Direction and <111> Although there was no orientation distribution in either direction, the pole figure in Figure 4, obtained by measuring a wide area using the XRD method, showed that the crystal <001> Direction and <111> The orientation distribution was observed in both directions, and a rolling recrystallization texture was observed.

[0048] <Crystal orientation distribution after shot peening> Next, the surface of the sample (same sample as sample A1) was subjected to shot peening under the conditions of a projection pressure of 0.6 MPa and a projection time of 10 minutes. For the shot peening, an air nozzle type shot peening device (Pneumatic Blaster, manufactured by Fuji Manufacturing Co., Ltd.) was used. Zircon particles were used as the shot material (projection material). The distance between the sample surface and the projection nozzle was 30 mm. In this way, a sample after shot peening (sample A2) was produced.

[0049] Next, the processed surface of the sample (sample A2) was observed using a scanning electron microscope. Figure 5 is an SEM photograph showing the cross-sectional microstructure near the processed surface of the sample. The processed surface of the sample refers to the surface of the sample that has been shot peened (the shot-peened surface). The cross section of the sample refers to a cross section along the thickness direction of the sample. The SEM photograph in Figure 5 shows that a plastically deformed area is visible in the region near the surface of the sample (region A in Figure 5). For example, it can be seen that a region that has undergone significant plastic deformation exists in the surface layer 50 μm to 100 μm deep (the region 50 μm to 100 μm deep from the surface of the sample), but that no significant plastic deformation has occurred further inside.

[0050] Next, the machined surface of the sample (sample A2) was analyzed using a scanning electron microscope equipped with an EBSD detector. Figure 6 is an IPF map obtained using the EBSD method, showing the crystal orientation distribution of the cross section near the machined surface of the sample. The IPF map in Figure 6 shows that grain refinement due to shot peening has occurred in the region from the machined surface of the sample to a depth of approximately 30 μm (region B in Figure 6). From these results, it can be said that the microstructure of the shot peened sample changes from the machined surface toward the interior.

[0051] Next, the sample (sample A2) was polished to a depth of 15 μm from the processed surface, and the polished surface (internal processed surface) was observed using a scanning electron microscope. Figure 7 is an SEM photograph of the internal processed surface of the sample. The SEM photograph in Figure 7 also shows that the crystal grains are fine in the internal processed surface 15 μm from the processed surface of the sample, and that large plastic deformation has occurred.

[0052] Next, the internal machined surface of the sample (sample A2) was analyzed using a scanning electron microscope equipped with an EBSD detector. Figure 8 is an IPF map obtained using the EBSD method, showing the crystal orientation distribution of the internal machined surface of the sample. The IPF map in Figure 8 also shows that the crystal grains are fine on the internal machined surface 15 μm inside the machined surface of the sample.

[0053] Figure 9 shows the crystal structure of the internally processed surface of the sample obtained by the EBSD method. <001> Direction and <111> The (001) pole figure and the (111) pole figure show the crystal orientation distribution of the direction. From the pole figures in Figure 9, as shown in the schematic diagram in the lower right of Figure 9, the easy axis of magnetization of Fe is <001> It can be seen that the orientation distribution is strong, with the direction of the magnetization easy axis being approximately parallel to the normal direction of the processed surface. <001> The direction is oriented approximately parallel to the normal direction of the processed surface, and <001> It can be seen that the direction of the magnetization is randomly distributed within the processed surface. <001> The peak of the highest intensity in the direction is strongly oriented between 0° and 15° from the normal direction of the plate surface of the processed surface, specifically at a position that forms an angle of about 11° with the normal direction of the plate surface. <001> The orientation is strongly distributed randomly in the direction between 75° and 105° from the normal direction of the plate surface of the processed surface, specifically between about 79° and 101° from the normal direction of the plate surface. <001> Although it is slightly smaller than the direction, it is the hard axis of magnetization. <111> The direction, <001> It can be seen that the orientation is weakly parallel to the normal direction of the processed surface, similar to the direction of the hard magnetization. <111> The peaks in the direction are formed between 0° and 15° from the normal to the plate surface and between 39° and 85° from the normal to the plate surface.

[0054] Next, the sample (sample A2) was analyzed using a powder X-ray diffractometer. Figure 10 shows the crystal structure of the processed surface of the sample obtained by the XRD method. <001> Direction and <111> The (001) pole figure and (111) pole figure show the crystal orientation distribution in the direction. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation distribution is strong and random within the processed surface. <111> The direction, <001> It can be seen that the crystal orientation is weakly parallel to the normal direction of the processed surface, similar to the direction of the grain boundary. Therefore, the results obtained by XRD (Fig. 10) are consistent with the results obtained by EBSD (Fig. 9). This crystal orientation distribution is similar to that of non-oriented electrical steel sheets, and is expected to improve the magnetic properties of Fe (iron).

[0055] <Effect of Shot Peening Pressure on Crystal Orientation Distribution after Shot Peening> The surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was then shot peened at a projection pressure of 0.2 MPa and 0.6 MPa for a projection time of 10 minutes. An air nozzle type shot peening device was used for the shot peening. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm. This produced a shot-peened sample (sample A3).

[0056] Next, the sample (sample A3) was polished to a depth of 15 μm from the processed surface, and the polished surface (internal processed surface) was observed using a scanning electron microscope. Figure 11 is an SEM image of the sample's internal processed surface. The SEM image in Figure 11 shows that the internal processed surface 15 μm from the processed surface of the sample has fine crystal grains and has undergone significant plastic deformation, in both samples that were shot peened at 0.2 MPa and 0.6 MPa.

[0057] Next, the internal machined surface of the sample (sample A3) was analyzed using a scanning electron microscope equipped with an EBSD detector. Figure 12 is an IPF map obtained using the EBSD method, showing the crystal orientation distribution of the internal machined surface of the sample. The IPF map in Figure 12 also shows that the crystal grains are fine on the internal machined surface 15 μm inside from the machined surface of the sample.

[0058] Figure 13 shows the crystal structure of the internal processed surface of the sample obtained by the EBSD method. <001> Direction and <111> The (001) and (111) pole figures show the distribution of crystal orientation in the direction of the easy axis of magnetization. From the pole figures in Figure 13, the specimen that was shot peened with a projection pressure of 0.2 MPa retained some of the rolling recrystallization texture, but the specimen that was shot peened with a projection pressure of 0.6 MPa retained some of the rolling recrystallization texture in the direction of the easy axis of magnetization. <001> The peak of the highest intensity in the direction is strongly oriented between 0° and 15° from the normal direction of the plate surface of the processed surface, specifically at a position that forms an angle of about 11° with the normal direction of the plate surface. <001> The orientation distribution is strong when the direction is between 75° and 105° from the normal to the plate surface of the processed surface, specifically between approximately 79° and 101° from the normal to the plate surface. This shows that the crystal orientation distribution of pure Fe can be controlled by adjusting the blast pressure of the blast material.

[0059] Next, the surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was shot peened at a projection pressure of 0.2 MPa and 0.6 MPa for a projection time of 30 minutes. An air nozzle type shot peening device was used for the shot peening. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm. This produced a shot peened sample (sample A4).

[0060] Next, the sample (sample A4) was analyzed using a powder X-ray diffractometer. Figure 14 shows the crystal structure of the processed surface of the sample obtained by the XRD method. <001> Direction and <111> The (001) and (111) pole figures show the crystal orientation distribution of the direction. From the pole figures in Figure 14, it can be seen that the specimens shot peened at 0.2 MPa and 0.6 MPa both have the same easy axis of magnetization. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation is strongly distributed so that the direction is random within the processed surface. Therefore, it can be said that if shot peening is performed for a longer time, even if the projection pressure is small, the crystal orientation distribution will improve the magnetic properties of pure Fe. However, in the case of a projection pressure of 0.6 MPa, by performing shot peening for a projection time of 30 minutes, the hard magnetization axis <111> The orientation of the Fe crystals, in which the direction is parallel to the normal to the processed surface, is stronger than with a 10-minute blasting time. Therefore, the crystal orientation distribution of pure Fe can be controlled by adjusting the blasting pressure and blasting time.

[0061] <Effect of Shot Peening Time on Crystal Orientation Distribution after Shot Peening> The surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was then shot peened at a projection pressure of 0.6 MPa for a projection time of 5 to 30 minutes (5 minutes, 10 minutes, 30 minutes). An air nozzle type shot peening device was used for the shot peening. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm. This produced a shot-peened sample (sample A5).

[0062] Next, the sample (sample A5) was analyzed using a powder X-ray diffractometer. Figure 15 shows the crystal structure of the processed surface of the sample obtained by the XRD method. <001> Direction and <111> The (001) pole figure and the (111) pole figure show the crystal orientation distribution of the direction. As the projection time increases, the easy axis of magnetization, <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation distribution becomes stronger, with the direction becoming random within the processed surface. <111> It can be seen that the orientation distribution in which the direction is parallel to the normal direction of the processed surface becomes stronger. Therefore, when shot peening pure Fe, <001> After the texture is formed, the direction of which is parallel to the normal direction of the processed surface, <111> It can be seen that a texture is also formed in which the direction is parallel to the normal direction of the processed surface. Therefore, an appropriate projection time is necessary to improve the magnetic properties of pure Fe.

[0063] <Effects of heat treatment after shot peening> Here, a sample that was not subjected to heat treatment after shot peening (sample A6) and a sample that was subjected to heat treatment after shot peening (sample A7) were prepared and compared to confirm the effect of heat treatment after shot peening.

[0064] To prepare sample A6, the surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was shot peened at a projection pressure of 0.6 MPa for a projection time of 10 minutes using an air nozzle type shot peening machine. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm. This resulted in the preparation of sample A6, which was not heat-treated after shot peening.

[0065] To prepare sample A7, the surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was shot peened at a projection pressure of 0.6 MPa for 10 minutes using an air nozzle type shot peening machine. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm.

[0066] The shot peened sample was then subjected to heat treatment. In the heat treatment, the sample was heated to a predetermined temperature and held for a predetermined time. The heating temperature was set to an optimum temperature within the range of 500°C to 650°C. The holding time (heating time) was set to an optimum time within the range of 0.5 hours to 5 hours. In this way, sample A7 was produced, which was heat treated after shot peening.

[0067] Next, specimens A6 and A7 were polished to 15 μm from the processed surface, and the polished surface (internal processed surface) was analyzed using a scanning electron microscope equipped with an EBSD detector. Figure 16 shows the crystal structure of the internal processed surface of specimens A6 and A7 obtained by the EBSD method. <001> Direction and <111> The (001) and (111) pole figures show the crystal orientation distribution in the direction.

[0068] From the pole figures of FIG. 16, it can be seen that the easy axis of magnetization is the same for both sample A6, which is not heat-treated after shot peening, and sample A7, which is heat-treated after shot peening. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation is strongly distributed so that the direction is random within the processed surface.

[0069] In addition, when comparing the two, sample A7, which was heat treated after shot peening, had a larger magnetization easy axis than sample A6, which was not heat treated after shot peening. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation distribution is stronger, with the direction becoming random within the processed surface. <111> It can be seen that the orientation distribution where the direction is parallel to the normal direction of the processed surface is weakened. <001> This allows us to fabricate samples with an orientation distribution in which only the crystal orientation is parallel to the normal direction of the processed surface, and with minimal lattice defects inside the sample. This allows us to precisely control the crystal orientation within the sample surface, further improving its magnetic properties.

[0070] <Effect of applying lubricant before shot peening> Here, a sample without lubricant applied before shot peening (sample A8) and a sample with lubricant applied before shot peening (sample A9) were prepared and compared to confirm the effect of applying a lubricant before shot peening.

[0071] To prepare sample A8, the surface of a sample (similar to sample A1) that had been annealed at 550°C for 1 hour was shot peened at a projection pressure of 0.6 MPa for 15 minutes using an air nozzle type shot peening machine. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was 30 mm. This resulted in the preparation of sample A8, which was not coated with a lubricant before shot peening.

[0072] To prepare sample A9, a sample (similar to sample A1) was annealed at 550°C for 1 hour, and a lubricant, boron nitride, was applied to the area to be shot peened (processed area) on the surface.

[0073] The lubricant-coated surface of the sample was then subjected to shot peening under conditions of a projection pressure of 0.6 MPa and a projection time of 15 minutes. An air nozzle type shot peening device was used for the shot peening. Zircon particles were used as the shot material. The distance between the sample surface and the projection nozzle was set to 30 mm. This resulted in the preparation of sample A9, which had been coated with lubricant before shot peening.

[0074] Next, specimens A8 and A9 were polished to 15 μm from the processed surface, and the polished surface (internal processed surface) was analyzed using a scanning electron microscope equipped with an EBSD detector. Figure 17 shows the crystal structure of the internal processed surface of specimens A8 and A9 obtained by the EBSD method. <001> Direction and <111> The (001) and (111) pole figures show the crystal orientation distribution in the direction.

[0075] From the pole figures in Figure 17, it can be seen that the easy axis of magnetization is the same for both specimen A8, which is not lubricated before shot peening, and specimen A9, which is lubricated before shot peening. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation is strongly distributed so that the direction is random within the processed surface.

[0076] In addition, when comparing the two, sample A9, which was applied with a lubricant before shot peening, had a magnetization easy axis that was closer to the magnetization easy axis than sample A8, which was not applied with a lubricant before shot peening. <001> The direction is parallel to the normal direction of the processed surface and other <001> It can be seen that the orientation distribution is stronger, with the direction becoming random within the processed surface. <111> It can be seen that the orientation distribution in which the crystal orientation is parallel to the normal direction of the processed surface is weakened. In this way, applying a lubricant before shot peening reduces friction between the sample surface and the shot material projected onto that surface during shot peening. As a result, the plastic deformation that occurs on the sample surface during shot peening has a small shear component and a large compressive component. This allows for precise control of the crystal orientation within the sample surface, further improving the magnetic properties.

[0077] (Other embodiments) The present invention is not limited to the above-described embodiments (examples), and it goes without saying that the present invention can be embodied in various forms without departing from the scope of the present invention.

[0078] The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified by the wording of the claims are embodiments of the present invention.

Claims

1. the <001> direction of the crystals in the surface plane of the metal plate made of pure iron is aligned approximately parallel to the normal direction of the plate surface, In measuring the crystal orientation distribution within the surface of the metal plate, in a (001) pole figure showing the crystal orientation distribution in the <001> direction of the crystal, at least one peak having a higher intensity than a group of peaks formed between 75° and 105° from the normal direction to the plate surface is detected between 0° and 15° from the normal direction to the plate surface. In-plane non-directional electromagnetic metal plate.

2. In the measurement, in a (111) pole figure showing the crystal orientation distribution in the <111> direction of the crystal, a group of peaks formed between 0° and 15° from the normal direction to the plate surface and between 39° and 85° from the normal direction to the plate surface is detected. The in-plane non-oriented electromagnetic metal sheet according to claim 1, wherein the crystal orientation distribution is such that a group of peaks formed between 0° and 15° from the normal direction to the plate surface and between 39° and 85° from the normal direction to the plate surface.

3. 3. The in-plane non-oriented electromagnetic metal plate according to claim 1, wherein the crystal orientation is oriented in at least a portion of the region including the surface of the metal plate from the surface to a depth of 100 μm.

4. A method for manufacturing an in-plane non-oriented electromagnetic metal plate in which the <001> direction of the crystal is aligned approximately parallel to the normal direction of the plate surface within the surface of the metal plate made of pure iron, a surface treatment process is performed by projecting a projectile onto the surface of the metal plate by shot peening; After the surface processing treatment, the metal plate is further subjected to heat treatment. Method for manufacturing in-plane non-oriented electromagnetic metal sheets.

5. 5. The method for manufacturing an in-plane non-oriented electromagnetic metal plate according to claim 4, wherein at least one of the projection pressure and projection time of the projection material in the surface processing treatment is adjusted to control the orientation state of the crystal orientation in the surface of the metal plate.

6. 6. The method for manufacturing an in-plane non-oriented electromagnetic metal plate according to claim 4, wherein a lubricant is applied to at least an area of ​​the surface of the metal plate to be subjected to the surface treatment before the surface treatment is performed.

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