Grain-oriented electrical steel sheet and method for producing grain-oriented electrical steel sheet

Abstract

The grain-oriented electrical steel sheet is provided with a plurality of magnetic domain control processing lines on the surface, and a rectangular evaluation region in which the length of the side parallel to the rolling direction of the grain-oriented electrical steel sheet is 50 mm and the length of the side parallel to the direction perpendicular to the rolling direction of the grain-oriented electrical steel sheet is 100 mm is set in the grain-oriented electrical steel sheet. When imaginary lines parallel to the direction perpendicular to the rolling direction and having a length of 100 mm are set at a 5 mm interval in a direction parallel to the rolling direction inside the evaluation region, in at least one of the imaginary lines, at least one of the imaginary lines has a length of 100 mm. The average value [beta] L of the absolute values of [beta] angles measured between two magnetic domain control points, which are the intersections of the virtual line and the magnetic domain control line, is 1.5 DEG or more, wherein the standard deviation of the interval between the magnetic domain control points is 1.25 mm or more, and the interval is the maximum value DL.

Description

Technical Field

[0001] This disclosure relates to oriented electromagnetic steel sheets and methods for manufacturing oriented electromagnetic steel sheets.

[0002] This application claims priority based on Japanese Patent Application No. 2023-166141, filed in Japan on September 27, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] Oriented electromagnetic steel sheets contain less than 7% by mass of Si and have an axis that facilitates magnetization. <001> {110} as secondary recrystallized grains oriented in the rolling direction <001> Oriented electromagnetic steel sheets are steel sheets with a secondary recrystallized texture formed by the aggregation of oriented grains (Goss oriented grains). Oriented electromagnetic steel sheets are mainly used as the cores of power transformers. For oriented electromagnetic steel sheets, it is required to reduce energy loss (iron loss).

[0004] To reduce iron loss, techniques for narrowing the domain width of oriented electromagnetic steel sheets (domain subdivision technology based on domain control processing) are previously known. Domain width can be narrowed by inducing thermal strain by irradiating the surface of the oriented electromagnetic steel sheet with a laser or electron beam in a direction intersecting the rolling direction. Alternatively, domain width can also be narrowed by forming grooves on the surface of the oriented electromagnetic steel sheet in a direction intersecting the rolling direction. Methods for forming these grooves include laser or electron beam irradiation, mechanical processing methods such as gear machining, and chemical processing methods such as etching.

[0005] In recent years, in order to provide oriented electromagnetic steel sheets with good iron loss characteristics, various improvement technologies related to magnetic domain subdivision have been proposed (for example, see Patent Documents 1 to 3).

[0006] In addition, in Patent Document 4, since even when local strain is applied for magnetic domain subdivision, there are problems such as low permeability due to the strain or increased noise due to increased magnetostriction, a low iron loss oriented electromagnetic steel sheet and its advantageous manufacturing method are proposed, which alleviate the problems of low permeability and increased magnetostriction caused by linear grooves and local strain for magnetic domain subdivision.

[0007] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2012-57219 Patent Document 2: Japanese Patent Application Publication No. 2012-12664 Patent Document 3: Japanese Patent Application Publication No. 2012-57218 Patent Document 4: Japanese Patent Application Publication No. H11-293340 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] When magnetic domain control is applied to oriented electromagnetic steel sheets, the magnetostrictive properties of the sheets change due to the closed magnetic domains. This deteriorates the noise characteristics of the oriented electromagnetic steel sheets. Noise characteristics refer to the level of noise generated by electrical products (such as transformers and motors) manufactured using oriented electromagnetic steel sheets as materials. Magnetostriction refers to the phenomenon of slight deformation of the shape when a strongly magnetic material is magnetized. When oriented electromagnetic steel sheets are excited using alternating current, the magnitude of magnetostriction changes with the intensity of magnetization, thereby generating vibration. The magnitude of this magnetostriction is 10. -6 Although the magnetostriction of the magnetostrictive field is very small, it causes the iron core to vibrate, which propagates to external structures such as transformer tanks and becomes noise. In other words, while magnetic domain control is effective in reducing iron losses in oriented electromagnetic steel sheets, it conversely worsens the noise characteristics of these sheets.

[0010] In recent years, there has been a growing demand for both low iron loss and low noise in oriented electromagnetic steel sheets. However, to date, no magnetic domain subdivision technology has been proposed that can fully achieve both low noise and low iron loss.

[0011] Furthermore, while Patent Document 4 mentions noise, it fails to fully achieve both low noise and low iron loss. Patent Document 4 discloses that the average β angle near the center of the grain's rolling direction is 0°, and magnetic domain control is applied only to the region where the reduction in iron loss due to magnetic domain control is significant, thus achieving both low noise and low iron loss. However, since the β angle near the center of the grain's rolling direction is not necessarily 0°, even using the method disclosed in Patent Document 4 for magnetic domain control processing cannot fully achieve both low noise and low iron loss.

[0012] The purpose of this disclosure is to provide an orientation-oriented electromagnetic steel sheet that achieves both low iron loss and low noise, and a method for manufacturing the same.

[0013] means for solving problems

[0014] The main purpose of this disclosure is as follows.

[0015] (1) In one embodiment of the present disclosure, the orientation-oriented electromagnetic steel sheet has multiple magnetic domain control processing lines on its surface. A rectangular evaluation area is defined in the orientation-oriented electromagnetic steel sheet, with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right-angle direction. Furthermore, within the evaluation area, imaginary lines of 100 mm length parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. In at least one of these imaginary lines, the standard deviation of the interval between the intersection point of the imaginary line and the magnetic domain control processing line (i.e., the magnetic domain control point) is 1.25 mm or more, and the interval becomes the maximum value D. L The average of the absolute values ​​of the β angle measured between the two domain control points |β L | is above 1.5°.

[0016] (2) According to the orientation electromagnetic steel sheet described in (1) above, preferably, among the two or more imaginary lines, the standard deviation of the interval between the magnetic domain control points is 1.25 mm or more and the interval becomes the maximum value D. L The average of the absolute values ​​of the β angle measured between the two domain control points |β L | is above 1.5°.

[0017] (3) According to the orientation electromagnetic steel sheet described in (1) or (2) above, preferably, the maximum value D of the interval of the magnetic domain control points is... L The minimum value D of the interval between the magnetic domain control point and the magnetic domain control point S The ratio of D L / D S It is 2 or higher.

[0018] (4) Preferably, the oriented electromagnetic steel sheet according to any one of (1) to (3) above, wherein the D L / D S The value is 4 or higher.

[0019] (5) According to the orientation electromagnetic steel sheet described in (3) or (4) above, preferably, the |β L | and at the interval where the minimum value D is... S The average of the absolute values ​​of the β angle measured between the two domain control points |β S | Satisfies the following formula. 0.5°≤|β L |-|β S |

[0020] (6) Preferably, the magnetic domain control processing line of the oriented electromagnetic steel sheet according to any one of (1) to (5) above is thermal strain.

[0021] (7) According to the orientation electromagnetic steel plate described in (6) above, preferably, the maximum value of the tensile stress introduced by the thermal strain in the magnetic domain control processing line is not uniform at each of the tensile stress measurement points.

[0022] (8) According to the orientation-oriented electromagnetic steel sheet described in (7) above, preferably, a rectangular evaluation area is set on the surface with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right-angle direction of the orientation-oriented electromagnetic steel sheet. Furthermore, inside the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. The multiple intersections of the imaginary lines and the multiple domain control processing lines are respectively set as domain control points. The maximum value of the tensile stress measured at each domain control point in MPa is set as TS. m The TS m Let the variance be σ(TS) m ) 2 hour, Satisfying σ(TS) m ) 2 >5.0.

[0023] (9) According to the orientation electromagnetic steel sheet described in (8) above, preferably, the arithmetic mean of the maximum tensile stress measured at each magnetic domain control point with a β angle less than 2° and incorporating the thermal strain, measured in MPa, is set as TS. m（β<2） The arithmetic mean of the maximum tensile stress measured at each of the domain control points with a β angle of 2° or greater, in units of MPa, which incorporates the thermal strain, is set as TS. m（β≥2） When, satisfy TS m（β<2） >TS m（β≥2） .

[0024] (10) The orientation electromagnetic steel sheet according to any one of (1) to (5) above, preferably, the magnetic domain control processing line is a groove.

[0025] (11) According to the orientation electromagnetic steel plate described in (10) above, preferably, the maximum value of the depth of the groove in the magnetic domain control processing line is not uniform at the depth measurement points of each groove.

[0026] (12) According to the orientation electromagnetic steel sheet described in (10) above, it is preferable to set a rectangular evaluation area on the surface with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right angle direction of the orientation electromagnetic steel sheet. Furthermore, inside the evaluation area, when imaginary lines with a length of 100 mm parallel to the rolling right angle direction are set at 5 mm intervals along a direction parallel to the rolling direction, the multiple intersections of the imaginary lines and the multiple domain control processing lines are respectively set as domain control points, and the maximum value of the groove depth measured in units of μm at each of the domain control points is set as D. m The D m Let the variance be σ(D) m ) 2 When σ(D) is satisfied m ) 2 >3.0.

[0027] (13) According to the orientation electromagnetic steel sheet described in (10) or (11) above, preferably, the arithmetic mean of the maximum values ​​of the groove depth measured in units of μm at each magnetic domain control point with a β angle less than 2° is set as D. m（β<2） The arithmetic mean of the maximum values ​​of the groove depth measured in μm at each of the domain control points with a β angle of 2° or greater is denoted as D. m（β≥2） When D is satisfied m（β<2） >D m（β≥2） .

[0028] (14) Another aspect of the present disclosure of a method for manufacturing an orientation-oriented electromagnetic steel sheet includes: a step of obtaining a magnetic domain image of a raw material of the orientation-oriented electromagnetic steel sheet; a step of determining a magnetic domain control processing area based on the distribution of magnetic domain widths in the magnetic domain image; and a step of applying magnetic domain control processing to the magnetic domain control processing area determined based on the distribution of magnetic domain widths; wherein a rectangular evaluation area is set in the orientation-oriented electromagnetic steel sheet, the length of the side parallel to the rolling direction of the orientation-oriented electromagnetic steel sheet is 50 mm, and the length of the side parallel to the rolling right-angle direction of the orientation-oriented electromagnetic steel sheet is 100 mm; and further, within the evaluation area, if imaginary lines of 100 mm length parallel to the rolling right-angle direction are set at 5 mm intervals along the direction parallel to the rolling direction, in at least one of the imaginary lines, the standard deviation of the interval along the imaginary lines between the intersection of the imaginary lines and the magnetic domain control processing lines formed by the magnetic domain control processing is set to 1.25 mm or more.

[0029] (15) In the manufacturing method of the oriented electromagnetic steel sheet described in (14) above, it is preferable that, in the process of determining the magnetic domain control processing area, the area where the magnetic domain width is above a predetermined value is set as the magnetic domain control processing area.

[0030] (16) In the method for manufacturing oriented electromagnetic steel sheet according to (14) or (15) above, it is preferred that, in the step of obtaining the magnetic domain image, the distribution of the magnetic domain width is derived from the magnetic domain image using a two-dimensional Fourier transform.

[0031] (17) In the method of manufacturing oriented electromagnetic steel sheet according to any one of (14) to (16) above, it is preferred that the magnetic domain control process is applied by irradiation with a laser or an electron beam in the step of applying the magnetic domain control process.

[0032] Invention Effects

[0033] According to the above-described solution of this disclosure, it is possible to provide an orientation-oriented electromagnetic steel sheet that achieves both low iron loss and low noise, and a method for manufacturing the same. Attached Figure Description

[0034] Figure 1A This is a top view of an orientation-type electromagnetic steel sheet according to one embodiment of the present disclosure.

[0035] Figure 1B This is a top view of an orientation-type electromagnetic steel sheet according to one embodiment of the present disclosure.

[0036] Figure 2 This is a top view of a typical oriented electromagnetic steel sheet.

[0037] Figure 3 This is a graph showing the relationship between the β angle and the domain width.

[0038] Figure 4A This is a diagram illustrating an example of the distribution of magnetic domain widths in an orientation-type electromagnetic steel sheet before magnetic domain subdivision processing.

[0039] Figure 4B This is a diagram illustrating an example of the distribution of magnetic domain widths in an orientation-oriented electromagnetic steel sheet after magnetic domain subdivision processing.

[0040] Figure 4C It is shown Figure 4A and Figure 4B A graph of the differences.

[0041] Figure 5 This is a graph showing the relationship between the domain width before and after domain control processing.

[0042] Figure 6This is a block diagram illustrating an example of the hardware configuration of an image acquisition device.

[0043] Figure 7 This is a block diagram illustrating an example of the hardware configuration of a parsing device.

[0044] Figure 8 This is a schematic diagram of an example of the structure of a laser irradiation device.

[0045] Figure 9 This is a flowchart illustrating a method for manufacturing an orientation-oriented electromagnetic steel sheet according to one embodiment of the present disclosure.

[0046] Figure 10 A schematic diagram illustrating a method for cutting out multiple partial regions from a magnetic domain image of an orientation-oriented electromagnetic steel sheet.

[0047] Figure 11 This is an example of obtaining multiple partial Fourier images by performing two-dimensional Fourier transforms on multiple partial regions cut out from the magnetic domain image of the oriented electromagnetic steel plate.

[0048] Figure 12 This is a top view of the original sheet of oriented electromagnetic steel.

[0049] Figure 13 It is a graph that schematically shows the relationship between the size of the domain width and the domain-controlled saturation intensity.

[0050] Figure 14 This is a graph that schematically illustrates the relationship between the magnitude of the β angle and the domain-controlled saturation intensity.

[0051] Figure 15 This is a schematic diagram of a cross-section of an orientation-type electromagnetic steel sheet with thermal strain as the magnetic domain control processing line.

[0052] Figure 16 This is a schematic diagram of the cross-section of an orientation-oriented electromagnetic steel plate with grooves formed by magnetic domain control processing lines.

[0053] Figure 17 This is a top view schematic diagram illustrating the method for measuring the magnetic domain control intensity at the intersection of the magnetic domain control processing line and the imaginary line when the magnetic domain control processing line is under thermal strain.

[0054] Figure 18 This is a top view schematic diagram illustrating the method for measuring the magnetic domain control intensity at the intersection of the magnetic domain control processing line and the imaginary line when the magnetic domain control processing line is a slot. Detailed Implementation

[0055] (1. Oriented electromagnetic steel sheet 1)

[0056] As illustrated in Figure 1, the orientation-oriented electromagnetic steel sheet 1 of this embodiment has multiple domain control processing lines 11 on its surface. Furthermore, in the orientation-oriented electromagnetic steel sheet 1 of this embodiment, a rectangular evaluation area is defined, with a side length of 50 mm parallel to the rolling direction RD and a side length of 100 mm parallel to the rolling right-angle direction TD. Within this evaluation area, imaginary lines VL, each 100 mm long and parallel to the rolling right-angle direction TD, are set at 5 mm intervals along a direction parallel to the rolling direction. In at least one imaginary line VL, the standard deviation of the interval between the intersection point (domain control point VP) of the imaginary line VL and the domain control processing line 11 is 1.25 mm or more, and the interval reaches its maximum value D. L The average absolute value of the β angle measured between the two domain control points |β L | is above 1.5°.

[0057] (Magnetic domain control processing line 11)

[0058] Multiple magnetic domain control lines 11 disposed on the surface of the oriented electromagnetic steel sheet 1 serve to subdivide 180° magnetic domains. By subdividing the magnetic domains, the iron loss of the oriented electromagnetic steel sheet 1 can be reduced. A magnetic domain refers to a collection of magnetic dipoles existing inside a strongly magnetic material, with the magnetic moment aligned along a small region. A 180° magnetic domain refers to a magnetization direction aligned with the crystal structure. <100> A domain is oriented and sandwiched between two 180° domain walls that are approximately parallel to the rolling direction RD. The distance between adjacent domain walls of a 180° domain (domain wall spacing) is called the width of the 180° domain. Hereinafter, unless otherwise specified, the width of the 180° domain will be simply referred to as the "domain width".

[0059] A preferred example of the magnetic domain control processing line 11 is thermal strain and groove. By subdividing the magnetic domains, the iron loss of the orientation-oriented electromagnetic steel sheet 1 can be suppressed. However, the magnetic domain control processing line 11 changes the magnetostrictive properties of the orientation-oriented electromagnetic steel sheet 1 by closing the magnetic domains. As a result, the noise characteristics of the orientation-oriented electromagnetic steel sheet 1 deteriorate.

[0060] The magnetic domain control processing line 11 is formed in a direction intersecting the rolling direction RD of the oriented electromagnetic steel sheet 1. Figure 2 In the typical oriented electromagnetic steel sheet 1 illustrated, the magnetic domain control processing lines 11 are formed across the entire width of the oriented electromagnetic steel sheet 1. However, in cases such as Figure 1A In the orientation-oriented electromagnetic steel plate 1 of this embodiment, it is not necessary to provide the magnetic domain control processing lines 11 throughout the entire width of the orientation-oriented electromagnetic steel plate 1.

[0061] exist Figure 1A In the illustrated orientation-oriented electromagnetic steel sheet 1, the magnetic domain control processing line 11 is a straight line. On the other hand, as... Figure 1B As shown, the domain control processing line 11 can also be curved. The domain control processing line 11 can also have a shape with straight sections and curved sections. Furthermore, the domain control processing line 11 can be located on one side or both sides of the orientation-oriented electromagnetic steel plate 1. When the domain control processing line 11 is located on both sides of the orientation-oriented electromagnetic steel plate 1, various configurations of the orientation-oriented electromagnetic steel plate 1 in this embodiment only need to be applied to at least one side of the orientation-oriented electromagnetic steel plate 1.

[0062] (Evaluation area)

[0063] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, in order to set the imaginary line VL described later, a rectangular evaluation area is set in the orientation-oriented electromagnetic steel sheet 1, with a side length of 50 mm parallel to the rolling direction RD of the orientation-oriented electromagnetic steel sheet 1 and a side length of 100 mm parallel to the rolling right-angle direction TD of the orientation-oriented electromagnetic steel sheet 1.

[0064] (Imaginary line VL, parallel to the right-angle direction of rolling TD and 100mm in length)

[0065] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, imaginary lines VL are conveniently used to determine the density of the magnetic domain control processing lines 11. The imaginary lines VL are set at 5mm intervals along a direction parallel to the rolling direction inside the evaluation area. Figure 1A The example shown depicts the state of drawing only one imaginary line VL. When multiple imaginary lines VL are set, it is possible to... Figure 1A The required number of other imaginary lines are set parallel to the imaginary line VL. The length of the imaginary line VL is 100 mm. The imaginary line VL extends parallel to the rolling right-angle direction TD. The intersection of the imaginary line VL and the domain control processing line 11 is defined as the domain control point VP. The spacing of the domain control points VP serves as an indicator of the density of the domain control processing line 11.

[0066] (Standard deviation of the interval of domain control points VP)

[0067] In the orientation-type electromagnetic steel sheet 1 of this embodiment, the standard deviation of the spacing of the domain control points VP along at least one imaginary line VL is 1.25 mm or more. The spacing d of the domain control points VP refers to the distance between two adjacent domain control points VP along the imaginary line VL. For example, in... Figure 1A The illustrated orientation-oriented electromagnetic steel sheet 1 has five magnetic domain control points VP on its imaginary line VL. When the standard deviation of the intervals d1 to d4 of these magnetic domain control points VP is greater than 1.25 mm, Figure 1A The orientation-oriented electromagnetic steel plate 1 satisfies the requirements of this disclosure related to the spacing of the magnetic domain control points VP.

[0068] Orientational electromagnetic steel plates capable of configuring one or more magnetic domain control points VP with a standard deviation of 1.25 mm or more for the imaginary line VL. Figure 1A As illustrated, interrupting the domain control processing line, etc., includes the region X where the domain control processing line 11 is intentionally not provided.

[0069] The standard deviation of the interval of the magnetic domain control points VP can vary depending on the configuration of the evaluation region and the position of the imaginary line VL. Figure 1A In the illustrated orientation-type electromagnetic steel sheet 1, the evaluation area and the imaginary line VL can also be positioned with a standard deviation of less than 1.25 mm for the spacing of the domain control points VP. However, the orientation-type electromagnetic steel sheet 1 that can be configured with one or more imaginary lines VL at arbitrary locations with a standard deviation of 1.25 mm or more for the spacing of the domain control points VP is considered to satisfy the requirements of this disclosure related to the spacing of the domain control points VP. Therefore, Figure 1A The orientation-oriented electromagnetic steel plate 1 satisfies the requirements of this disclosure related to the spacing of the magnetic domain control points VP.

[0070] on the other hand, Figure 2 The illustrated orientation-type electromagnetic steel plate 1, with multiple domain control processing lines 11 evenly spaced across its entire width, does not include the region X where no domain control processing lines 11 are provided. Figure 2 In the orientation-oriented electromagnetic steel sheet 1, the standard deviation of the spacing of the magnetic domain control points VP cannot be configured, resulting in an imaginary line VL with a spacing of 1.25 mm or more. Therefore, Figure 2 The orientation-oriented electromagnetic steel plate 1 does not meet the requirements of this disclosure related to the spacing of the magnetic domain control points VP.

[0071] (β angle)

[0072] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, the β angle measured in the magnetic domain control processing line 11 is set within a specified range. The β angle refers to the offset angle of the grains relative to the Goss orientation around the axis of the rolling right-angle direction TD. It is known that controlling the β angle is effective for controlling the magnetic properties of the orientation-oriented electromagnetic steel sheet 1. The offset angle of the grains relative to the Goss orientation around the axis of the rolling surface normal direction ND is called the α angle, and the offset angle of the grains relative to the Goss orientation around the axis of the rolling direction RD is called the γ angle.

[0073] exist Figure 12 In the orientation electromagnetic steel plate 1 (original plate 2 described later) before the magnetic domain control treatment shown, there is a close relationship between the β angle and the magnetic domain width. Figure 3This is a graph illustrating an example of the relationship between the β angle and the average value of the domain width in the orientation-oriented electromagnetic steel sheet 1 before domain control treatment. In the orientation-oriented electromagnetic steel sheet 1 before domain control treatment, the smaller the β angle, the larger the domain width. However, in the orientation-oriented electromagnetic steel sheet 1 after domain control treatment, Figure 3 The relationship shown does not hold. This is because the domain control process reduces the domain width in regions where the domain width was wide before domain control, while not changing the orientation (α angle, β angle, γ angle) of the grains.

[0074] (|β) L |)

[0075] In the orientation-type electromagnetic steel sheet 1 of this embodiment, in an imaginary line VL where the standard deviation of the interval between the domain control points VP is 1.25 mm or more, the β angle measured between the two domain control points VP with the longest interval is defined. Specifically, when the interval is the maximum value D mentioned above... L The average absolute value of the β angle measured between the two domain control points VP |β L | is above 1.5°.

[0076] like Figure 1A As shown, in the imaginary line VL where the standard deviation of the spacing of the domain control points VP of the orientation electromagnetic steel sheet 1 in this embodiment is 1.25 mm or more, there exists a region X where no domain control processing has been performed, and there are areas where adjacent domain control points VP are widely separated. On the other hand, in a typical orientation electromagnetic steel sheet 1 after domain control processing, where multiple domain control processing lines 11 are arranged at equal intervals throughout the entire width, there is no region X where no domain control processing has been performed. Furthermore, even assuming that there is a region X in the orientation electromagnetic steel sheet 1 after typical domain control processing, that is, even if the orientation electromagnetic steel sheet 1 is an orientation electromagnetic steel sheet 1 where multiple domain control processing lines 11 are arranged randomly at unequal intervals, the domain width in this region X is wide, and the β angle is small.

[0077] Therefore, assuming that a region X without domain control treatment is provided in a typical orientation-oriented electromagnetic steel sheet 1, the average absolute value of the β angle in the imaginary line VL passing through this region is small, and the domain width becomes large. Those skilled in the art should attempt to minimize the size of the region X without domain control treatment. However, in the orientation-oriented electromagnetic steel sheet 1 of this embodiment, the domain width in the region X without domain control treatment is narrow, and the |β angle measured in region X... L | represents a large value.

[0078] |β L |More preferably, it is 1.5° or higher, 2.0° or higher, or 2.5° or higher. |β LThe upper limit of | is not particularly limited, but is further preferably 10.0° or less, 7.0° or less, or 5.0° or less.

[0079] (Basic principles and effects)

[0080] The inventors discovered that, based on an imaginary line VL in which the standard deviation of the interval of the domain control points VP can be set to be 1.25 mm or more, and |β| measured in this imaginary line VL... L | An orientation-grade electromagnetic steel sheet 1 with an orientation angle of 1.5° or higher can achieve both low iron loss and low noise. This is because, in such an orientation-grade electromagnetic steel sheet 1, magnetic domain control treatment is applied only to the portions that contribute to reducing iron loss, and magnetic domain control treatment lines 11 are not provided in the portions where magnetic domain control treatment is not required. Hereinafter, refer to... Figures 4A-4C The basic principles and effects of this disclosure are explained.

[0081] First, the inventors compared the magnetic domain structure of the orientation electromagnetic steel plate 1 before and after the magnetic domain control treatment. Figure 4A The diagram shows an example of the distribution of magnetic domain widths in an orientation-type electromagnetic steel sheet 1 before magnetic domain control treatment. Figure 4B The middle shows the Figure 4A The distribution of domain widths on the surface of the oriented electromagnetic steel sheet 1 after domain control treatment. The domain control treatment here is accomplished by continuous wave laser irradiation along a direction inclined at 2° relative to the rolling direction RD. Figure 4A and Figure 4B The distribution of magnetic domain widths shown was derived from the magnetic domain image of the orientation electromagnetic steel plate 1 using the two-dimensional Fourier transform described later.

[0082] Furthermore, in Figure 4C The middle shows Figure 4A and Figure 4B The difference. Figure 4C Indicates in Figure 4A and Figure 4B The domain width before and after the domain control processing is subdivided into regions larger than 50 μm. According to... Figure 4C The regions where the domain width is subdivided through domain control processing are visualized. Figures 4A-4C In this context, the unit of measurement is μm.

[0083] according to Figure 4C It can be seen that the region with magnetic domain subdivision of over 50 μm produced by magnetic domain control processing is... Figure 4A The dark areas represent regions with wide domain widths in the initial stage of domain control processing. In particular, it is evident that the domain subdivision effect is significantly observed in regions where the original domain width is approximately 500 μm or more. On the other hand, in... Figure 4AIn the bright areas, which represent the regions with narrow domain widths in the initial stage of domain control processing, the effect of domain control processing is almost negligible. This indicates that the effectiveness of domain control processing varies depending on the domain width before processing.

[0084] The inventors investigated in more detail the relationship between the reduction in domain width resulting from domain control processing and the domain width before domain control processing. Figure 5 The diagram shows the relationship between the domain width before and after domain control processing at the same location. Domain control processing is set as laser irradiation. During laser irradiation, the average irradiation energy density Ua (mJ / mm²) is... 2 The irradiation spacing PL (mm) is set to Ua = 1.5 mJ / mm. 2 PL=4mm.

[0085] according to Figure 5 It is evident that the domain subdivision effect of domain control processing is difficult to manifest in regions with narrow domain widths. Particularly in regions with domain widths below approximately 500 μm, the domain widths before and after domain control processing are roughly the same. Therefore, it is believed that the reduction in iron loss brought about by domain control processing is greater in regions with wider domain widths before domain control, but not sufficiently achieved in regions with sufficiently narrow domain widths before domain control. It is also believed that the domain control processing line 11 formed in regions with narrow domain widths leads to a deterioration in noise characteristics caused by closed domains.

[0086] Based on the above insights, it is believed that in the previous domain control processing of oriented electromagnetic steel sheet 1, domain control was performed on areas where it was not necessary, which contributed to increased noise. Furthermore, it is known that preferentially performing domain control processing in regions with wide domain widths (i.e., regions with small β angles) is extremely effective in achieving both low iron loss and low noise. Domain control processing in regions with wide domain widths can reduce iron loss. Additionally, by minimizing domain control processing in regions with narrow domain widths (i.e., regions with large β angles), the deterioration of noise characteristics can be prevented.

[0087] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, no magnetic domain control processing lines 11 are provided in regions where the magnetic domain width is narrow before the magnetic domain control processing. Therefore, the orientation-oriented electromagnetic steel sheet 1 of this embodiment includes a region X in which no magnetic domain control processing lines 11 are provided. When an evaluation region and an imaginary line VL are set in this region X, the standard deviation of the spacing of the magnetic domain control points VP along the imaginary line VL becomes 1.25 mm or more. By not providing magnetic domain control processing lines 11, the noise characteristics of the orientation-oriented electromagnetic steel sheet 1 of this embodiment are improved.

[0088] Furthermore, region X, where the domain control processing line 11 is not provided, is a region with narrow domain width and large β angle before the domain control processing. Therefore, in the orientation-oriented electromagnetic steel sheet 1 of this embodiment, the β angle is also large in region X where the domain control processing line 11 is not provided. In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, region X, where the domain control processing line 11 is not provided, does not impair iron loss.

[0089] Furthermore, in the orientation-oriented electromagnetic steel sheet 1 of this embodiment, magnetic domain control processing is performed in regions with wide magnetic domain widths before the magnetic domain control processing. Therefore, the iron loss of the orientation-oriented electromagnetic steel sheet 1 of this embodiment is improved by the magnetic domain control processing.

[0090] The most basic embodiment of the orientation-oriented electromagnetic steel sheet 1 has been described above. Further preferred embodiments will now be described.

[0091] (The standard deviation of the interval of the domain control points VP is the number of imaginary lines VL with a spacing of 1.25 mm or more.)

[0092] According to the research results of the inventors, in the original plate 2 before magnetic domain control treatment, regions with narrow magnetic domain widths (regions that do not require magnetic domain control treatment) are dispersed throughout the surface of the original plate 2. It is preferable to avoid all regions with narrow magnetic domain widths dispersed throughout the surface of the original plate 2 and to perform magnetic domain control appropriately. Therefore, in the orientation electromagnetic steel plate 1 after magnetic domain control treatment, it is also preferable that the regions X without magnetic domain control treatment lines 11 are dispersed throughout the surface.

[0093] Therefore, in the orientation-oriented electromagnetic steel sheet 1 of this embodiment, it is preferable that, within the evaluation area, imaginary lines VL, parallel to the rolling right-angle direction TD and 100 mm in length, are set at 5 mm intervals, and in each of two or more imaginary lines VL, the standard deviation of the interval between the domain control points VP is 1.25 mm or more, and the interval becomes the maximum value D. L The average absolute value of the β angle measured between the two domain control points |β L | 1.5° or more. That is, preferably, the standard deviation of the interval between two or more magnetic domain control points VP that can be set is 1.25 mm or more and |β L |The degree of the imaginary line VL is greater than or equal to 1.5°, and the region X in the orientation-oriented electromagnetic steel plate 1 is not provided with magnetic domain control treatment lines 11. The standard deviation of the spacing of the magnetic domain control points VP is greater than or equal to 1.25 mm and |β L The number of imaginary lines VL with an angle of 1.5° or higher is further preferably 3 or more, 4 or more, 5 or more, or 10 or more.

[0094] (D) L / D S )

[0095] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, the characteristic is that magnetic domain control processing is selectively performed on regions with wide magnetic domain widths before magnetic domain control. However, in this case, compared with steel sheets with general grain sizes, more significant effects can be obtained by performing the above-described processing on steel sheets with coarse grain sizes.

[0096] For example, generally speaking, when trying to increase the orientation density towards the Goss orientation to improve magnetic flux density, there is a tendency for the grain size to increase due to the manufacturing process. While steel sheets with such coarse grain sizes have excellent magnetic flux density, the excessively large grains tend to result in high iron losses without domain control treatment; therefore, domain control is practically necessary. However, as mentioned above, while conventional domain control treatment is effective in reducing iron losses in orientation-oriented electromagnetic steel sheets, it conversely tends to deteriorate the noise characteristics of these sheets.

[0097] On the other hand, for steel plates with large grain size, as in this embodiment, if magnetic domain control processing is selectively applied to regions with wide magnetic domain widths before magnetic domain control, in addition to excellent magnetic flux density, orientation-oriented electromagnetic steel plates that can achieve both low iron loss and low noise can be obtained.

[0098] If the magnetic domain control treatment specific to this embodiment is applied to a steel sheet with a coarse grain size, then due to the coarse grain size of the steel sheet, among the above characteristics, especially the maximum value D... L With minimum value D S The ratio of D L / D S The value changes.

[0099] Specifically, in the orientation-oriented electromagnetic steel plate 1 of this embodiment, the maximum value D of the spacing between the magnetic domain control points is... L Minimum value D of the interval with the domain control point S The ratio of D L / D S Preferably, it is 2 or higher. This further improves both iron loss characteristics and noise characteristics. More preferably, it is D. L / D S A score of 4 or higher. (D) L / D S There is no upper limit to D. As needed, D L / D S The upper limit can be set to 24.

[0100] (|β) L | and |β S (relationship)

[0101] In an imaginary line VL where the standard deviation of the interval between the domain control points VP is greater than 1.25 mm, |β L | and at an interval of the minimum value D mentioned above S The average absolute value of the β angle measured between the two domain control points VP |β S | Further optimization is needed to satisfy the following formula. 0.5°≤|β L |-|β S |

[0102] In |β L |-|β S When the β angle is 0.5° or higher, it indicates that the region for implementing domain control processing is selectively determined by the β angle. Because domain control processing is concentrated in regions with wide domain widths and significant iron loss reduction before domain control, further improvements in noise characteristics can be achieved. L |-|β S There is no upper limit to |.

[0103] (Magnetic domain control processing line 11)

[0104] The type of magnetic domain control processing line 11 is not particularly limited, but preferred examples are thermal strain and / or grooves. Thermal strain can be formed, for example, by means of laser irradiation, electron beam irradiation, and ion implantation. Grooves can be formed, for example, by means of laser irradiation, electron beam irradiation, and machining.

[0105] Thermal strain disappears through stress-relief annealing or heat treatment based thereon. Therefore, when the orientation-oriented electromagnetic steel sheet 1 is heat-treated, the domain control processing line 11 is preferably provided as a groove. On the other hand, since thermal strain can be easily formed, the domain control processing line 11 is preferably provided as thermal strain when simplification of the manufacturing process is required. The orientation-oriented electromagnetic steel sheet 1 may also have both thermal strain and groove.

[0106] In the oriented electromagnetic steel sheet of this disclosure, it is preferable that the index of the strength of magnetic domain control in the magnetic domain control processing line, i.e., the depth of the groove or the maximum value of the tensile stress introduced by thermal strain, is not uniform at the measurement points of the depth of the groove or the tensile stress.

[0107] The greater the intensity of domain control, the better the effect of domain subdivision. On the other hand, the greater the intensity of domain control, the more likely it is to lead to increased hysteresis loss and deterioration of noise characteristics. According to the new insights of the inventors, the saturation intensity of domain control is different in oriented electromagnetic steel sheets. Therefore, it is preferable to make the domain control intensity non-uniform based on the domain control saturation intensity.

[0108] Domain control saturation intensity refers to the domain control intensity at which the effect of domain subdivision processing is substantially saturated. When the domain control intensity is below the domain control saturation intensity, a higher domain control intensity results in lower iron loss. However, when the domain control intensity exceeds the domain control saturation intensity, even increasing the domain control intensity yields almost no improvement in iron loss reduction. On the other hand, even when the domain control intensity exceeds the domain control saturation intensity, a higher domain control intensity leads to increased hysteresis loss and worsened noise characteristics. Therefore, the domain control intensity is ideally located within the range not exceeding the domain control saturation intensity.

[0109] When the domain control processing line is thermal strain, the intersection points of the imaginary line and multiple domain control processing lines are respectively taken as domain control points. The maximum value of the tensile stress measured at each domain control point and in MPa after introducing thermal strain is set as TS. m TS m Let the variance be σ(TS) m ) 2 When, it is more preferable to satisfy σ(TS) m ) 2 >5.0.

[0110] "Maximum value of tensile stress with thermal strain" refers to the maximum value of tensile stress measured in an arbitrary cross-section. Tensile stress is not uniform in a cross-section; therefore, a specific "maximum value of tensile stress with thermal strain" is required for each cross-section. For example... Figure 15 As schematically shown, the thermal strain 541 extends to a certain extent within the cross-section. The tensile stress is highest at the location directly irradiated by the laser, and lowest at locations further away. That is, the measured tensile stress values ​​differ at various measurement points within the cross-section. Based on the tensile stress measurement method described later, the distribution and maximum value of the tensile stress within the cross-section can be derived.

[0111] When the domain control intensity is uniform, the maximum value of the tensile stress introduced by the thermal strain 541 becomes constant throughout the entire domain control processing line 11. On the other hand, when the domain control intensity is non-uniform, the maximum value of the tensile stress introduced by the thermal strain in the domain control processing line is not uniform at each tensile stress measurement point. Hereinafter, the maximum value of the tensile stress introduced by the thermal strain will sometimes be simply referred to as "tensile stress".

[0112] Furthermore, the inventors discovered a strong correlation between domain control saturation intensity and the β angle. The β angle refers to the offset angle of a grain relative to the Goss orientation around the axis of the rolling right angle (TD). At locations with a small β angle, the domain control saturation intensity is high. Additionally, a correlation exists between the β angle and the domain width in the oriented electromagnetic steel sheet before domain control treatment. In the oriented electromagnetic steel sheet before domain control treatment, a larger β angle results in a smaller domain width. However, in the oriented electromagnetic steel sheet after domain control treatment, the correlation between domain width and the β angle decreases. This is because the domain control treatment changes the domain width but not the β angle.

[0113] Therefore, it is preferable to select the optimal domain control strength based on the domain width or the β angle. For example, it is preferable to perform domain subdivision processing with high domain control strength in regions with large domain width and small β angle, and to perform domain subdivision processing with low domain control strength in regions with small domain width and large β angle. In addition, as mentioned above, domain subdivision processing is not performed in regions where the original domain width is narrow.

[0114] Specifically, TS is defined as the arithmetic mean of the maximum tensile stress measured at each domain control point with a β angle less than 2°, in units of MPa, after incorporating thermal strain. m（β<2） The arithmetic mean of the maximum tensile stress measured at each domain control point with a β angle of 2° or higher, in units of MPa, after incorporating thermal strain, is defined as TS. m（β≥2） When, it is preferable to satisfy TS m（β<2） >TS m（β≥2） .

[0115] In this case, the iron loss of the orientation-oriented electromagnetic steel sheet is further reduced after domain control. On the other hand, the increase in hysteresis loss and the deterioration of noise characteristics of the orientation-oriented electromagnetic steel sheet after domain control are further suppressed.

[0116] use Figure 17 Explanation of TS m and σ (TS) m ) 2 An example of a determination method. Figure 17 The dashed lines in the diagram are multiple imaginary lines VL set at 5mm intervals, parallel to the right-angle rolling direction TD of the oriented electromagnetic steel sheet. Figure 17 The × and O marks represent the intersections of the imaginary line VL and the thermal strain 541, which serves as the magnetic domain control processing line. It should be noted that the β angle at locations marked with × is greater than 2°, while the β angle at locations marked with O is less than 2°. However, in calculating σ(TS)... m ) 2 When the angle β at the intersection point is not considered, it is not necessary to consider the angle β at the intersection point.

[0117] First, the rolling right-angle direction TD of the oriented electromagnetic steel sheet is specified. The rolling right-angle direction TD can be specified by a method described later. Next, imaginary lines VL are set at 5mm intervals parallel to the rolling right-angle direction TD of the oriented electromagnetic steel sheet. Then, the intersection of the imaginary line VL and the thermal strain 541, which serves as a magnetic domain control processing line, is specified. When the thermal strain 541 cannot be visually identified with the naked eye, it is specified based on a magnetic domain image. The shape of the measurement area is preferably set as a rectangle with a size of 50mm or more along the rolling direction RD and a size of 100mm or more along the rolling right-angle direction TD. One side of the rectangle is preferably parallel to the rolling direction RD.

[0118] Then, a rectangular evaluation area with a length of 50 mm parallel to the rolling direction and a length of 100 mm parallel to the rolling right-angle direction is set on the surface. Furthermore, within the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. The TS (Transmission Time) at the intersection points of all imaginary lines and the magnetic domain control processing lines in the set area is measured. m Calculate TS m variance σ (TS) m ) 2 Tensile stress TS introduced in thermal strain m Determined using the EBSD Wilkinson method and the Cross Court method manufactured by BLG Vantage.

[0119] When determining the magnitude of tensile stress introduced into thermal strain using the EBSD Wilkinson method and a Cross Court manufactured by BLG Vantage, the thermal strain 541, specifically designated as the domain control processing line, is first determined according to the steps described above. Next, the orientation-oriented electromagnetic steel sheet 1 is cut through the domain control processing line and perpendicular to it. This cut surface is used as the measurement surface. For the cross section containing the domain control processing line within the measurement surface, analysis is performed using the EBSD Wilkinson method and a Cross Court manufactured by BLG Vantage to extract the tensile stress components relative to any direction and determine their magnitude. For example, tensile stress components in the direction normal to the rolling surface, in the direction parallel to the domain control processing line, and in the direction perpendicular to both the rolling surface normal and the domain control processing line can be extracted.

[0120] The maximum value of specific tensile stress TS at multiple measurement points. M variance σ (TS) M ) 2The population variance was derived according to the method described in paragraph 2.36 of JIS Z8101-1:2015, “Statistics – Terms and Symbols – Part 1: Terms and Symbols for General Statistics and Terms for Using in Accuracy”.

[0121] In addition, TS was determined using the following method. m（β<2） and TS m（β≥2） .

[0122] First, the β angle at the intersection point is determined, specifically for intersections with a β angle greater than 2° and intersections with a β angle less than 2°. The β angle in oriented electromagnetic steel sheets is determined using the side-reflection Laue method. The side-reflection Laue method is widely known as a method for determining crystal orientation.

[0123] Next, the maximum tensile stress TS is specified at all intersections where the β angle is greater than 2°. m Calculate the arithmetic mean of these values. Treat this value as TS. m（β≥2） .

[0124] Furthermore, the maximum value of the tensile stress TS is specified at all intersections where the β angle is less than 2°. m Calculate the arithmetic mean of these values. Treat this value as TS. m（β<2） The maximum tensile stress TS at the intersection of thermal strain 541 is introduced. m The determination method is as described above.

[0125] When the domain control processing line is a groove, a rectangular evaluation area is set on the surface with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right-angle direction. Then, inside the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. Multiple intersections of the imaginary lines with multiple domain control processing lines are designated as domain control points. The maximum value of the groove depth measured in μm at each domain control point is set as D. m D m Let the variance be σ(D) m ) 2 When, it is more preferable to satisfy σ(D) m ) 2 >3.0.

[0126] In this case, the domain control intensity changes based on the domain width or the β angle, and the increase in hysteresis loss and the deterioration of noise characteristics of the oriented electromagnetic steel sheet after domain control are further suppressed.

[0127] Additionally, the arithmetic mean of the maximum values ​​of the groove depth measured in μm at each domain control point with a β angle less than 2° is denoted as D.m（β<2） The arithmetic mean of the maximum values ​​of the groove depth measured in μm at each of the domain control points with a β angle of 2° or greater is denoted as D. m（β≥2） Then, further optimize to satisfy D m（β<2） >D m（β≥2） .

[0128] In this case, within the domain control processing line, the domain control strength is high where the β angle is small and low where the β angle is large. Therefore, the iron loss of the orientation-oriented electromagnetic steel sheet is further reduced after domain control. On the other hand, it further suppresses the increase in hysteresis loss and the deterioration of noise characteristics in the orientation-oriented electromagnetic steel sheet after domain control.

[0129] D m and σ(D) m ) 2 An example of the determination method in Figure 18 As shown in the image. Figure 18 The dashed lines in the diagram are multiple imaginary lines VL set at 5mm intervals, parallel to the right-angle rolling direction TD of the oriented electromagnetic steel sheet. Figure 18 The × and O marks represent the intersections of the imaginary line VL and the slot 542, which serves as the domain control processing line. The β angle at locations marked with × is greater than 2°, while the β angle at locations marked with O is less than 2°. However, in calculating σ(D... m ) 2 When the angle β at the intersection point is not considered, it is not necessary to consider the angle β at the intersection point.

[0130] First, the rolling direction of the specific orientation electromagnetic steel sheet. Next, imaginary lines VL are set parallel to the rolling right-angle direction TD of the electromagnetic steel sheet at 5mm intervals. Then, the intersection of the specific imaginary line VL and the domain control processing line is determined. The domain control processing line is... Figure 16 In the case of such a groove 542, the magnetic domain control processing line can be easily identified visually. The shape of the measurement area is preferably set as a rectangle with a size of 50 mm or more along the rolling direction RD and a size of 100 mm or more along the rolling right-angle direction TD. One side of the rectangle is preferably parallel to the rolling direction RD.

[0131] Then, a rectangular evaluation area is defined with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right-angle direction. Furthermore, within the evaluation area, imaginary lines of 100 mm length parallel to the rolling right-angle direction are set at 5 mm intervals along the direction parallel to the rolling direction. The maximum value D of the groove depth at the intersection of all imaginary lines and the domain control processing lines in the defined area is measured. m Calculate the maximum value D of the groove depth. m The variance σ(D)m ) 2 The maximum depth D of the groove. m The determination method is as follows.

[0132] Measurements were performed using a Bruker Controll GT-I white-light interferometer. The lens used consisted of a 5x objective lens (0.12 apertures, 2.2μm optical resolution) and a 1x internal lens. A white LED was used as the light source, and a monochrome CCD (1200×1000 pixels) was used as the camera. The pixel size was set to 1.37μm. Using Vision64 Map Premium 9.2 software, tilt correction based on the least-squares plane was performed, followed by a Goss filter with a cutoff of 2.5mm to remove long-wavelength fluctuations before analysis. Alternatively, the pixel size could be resampled to 10μm as needed during analysis. Furthermore, areas clearly identified as outliers could be excluded from the analysis. Depending on the characteristics of the sample, the type of lens, filter value, and correction method could be changed. Although grooves were formed on the oriented electromagnetic steel plate, when it was impossible to measure the surface irregularities using methods such as insulating coatings, the above measurements were performed after removing the insulating coating using known methods.

[0133] First, the β angle at the intersection points is measured, specifically for intersection points with a β angle greater than 2° and intersection points with a β angle less than 2°. Next, the D value at all intersection points with a β angle greater than 2° is calculated. m The arithmetic mean of D is taken as D. m（β≥2） Furthermore, calculate D at all intersection points where the β angle is less than 2°. m The arithmetic mean of D is taken as D. m（β<2） The maximum depth D of the groove at the intersection. m The determination method is as described above.

[0134] (2. Manufacturing apparatus for oriented electromagnetic steel sheet 1)

[0135] Next, an example of the manufacturing apparatus for the orientation-oriented electromagnetic steel sheet 1 of this embodiment will be described. However, the manufacturing apparatus described below is merely illustrative. The orientation-oriented electromagnetic steel sheet 1 of this embodiment can be manufactured using any apparatus.

[0136] Figure 6 This illustration shows an example of the hardware configuration of an image acquisition device 30 that acquires magnetic domain images of the original plate 2, i.e., the orientation electromagnetic steel plate 1 before magnetic domain control processing. The image acquisition device 30 includes a light source unit 31, a magneto-optical sensor (MO sensor 33), an image sensor 35, and a signal processing unit 37.

[0137] The light source unit 31 has a light source composed of light-emitting diodes (LEDs) that illuminates the MO sensor 33 with light of the same polarization plane.

[0138] The MO sensor 33 is a device for measuring the magnetic domain structure of a magnetic material. The MO sensor 33 has an observation surface on which the magnetic material sample to be measured is placed. Light irradiated from the light source 31 is reflected by a reflective layer inside the MO sensor 33. The reflected light passes through the interior of the MO sensor 33 again and is output to the exterior. When the original plate 2, which is the magnetic material sample, is placed on the observation surface of the MO sensor 33, a leakage magnetic field corresponding to the spontaneous magnetization of the original plate 2 is generated inside the MO sensor 33. Through this leakage magnetic field, the polarization plane of the reflected light rotates.

[0139] Image sensor 35 is a complementary metal-oxide-semiconductor (CMOS) image sensor. Image sensor 35 images the reflected light from MO sensor 33 onto the light-receiving surface and performs photoelectric conversion, outputting the photoelectric converted analog signal to signal processing unit 37. By using image sensor 35 to detect the reflected light after the polarization plane is rotated, the distribution of the leakage magnetic field can be obtained, and the magnetic domain structure of the original plate 2 becomes clear.

[0140] The signal processing unit 37 includes an amplifier, an analog-to-digital converter (ADC), and a digital signal processor (DSP). The analog signal output from the image sensor 35 is amplified by the amplifier. Then, the analog signal is converted into a digital signal by the ADC. An image signal is generated by performing prescribed digital processing on the digital signal using the DSP. The image signal generated by the signal processing unit 37 is output to the analysis device 40 (see reference 40) via cable or wireless communication. Figure 7 ).

[0141] Figure 7 The hardware configuration of the analysis device 40 for analyzing the magnetic domain structure of the original board 2 is shown. The analysis device 40 is a computer device such as a personal computer (PC). The analysis device 40 includes an arithmetic unit 41, a memory 43, a display unit 45, an input unit 47, and a communication I / F 49.

[0142] The arithmetic unit 41 has a central processing unit (CPU). The arithmetic unit 41 parses the domain structure from the domain image of the original board 2 according to a program stored in the memory 43. Then, the arithmetic unit 41 determines the domain control processing region 21 as the location for applying domain control processing. The processing performed by the arithmetic unit 41 will be described in detail later.

[0143] The memory 43 includes a read-only memory (ROM) and a random access memory (RAM). The ROM stores programs executed by the CPU of the arithmetic unit 41 and the data required to execute these programs. The programs and data stored in the RAM are loaded into the RAM and executed.

[0144] The memory 43 may also be a magnetic storage device such as a hard disk drive (HDD) or an optical storage device such as an optical disc. Alternatively, the memory 43 may be removable from the parsing device 40 and store programs and data on a computer-readable recording medium. Alternatively, the memory 43 may also receive programs executed by the arithmetic unit 41 from a network via the communication I / F 49.

[0145] Display unit 45 includes a liquid crystal display (LCD), a plasma display, or an organic electroluminescent (EL) display. Display unit 45 displays an image based on an image signal output from image acquisition device 30. Additionally, display unit 45 displays the analysis results based on the magnetic domain structure of arithmetic unit 41.

[0146] Input unit 47 includes input devices such as a mouse and keyboard. Communication I / F 49 is an interface for sending and receiving data with external devices via networks such as local area networks (LANs), wide area networks (WANs), and the Internet.

[0147] As the computing unit 41, it can also replace general-purpose hardware such as CPUs and adopt special-purpose integrated circuits (ASICs) or field-programmable gate arrays (FPGAs) specifically designed for the analysis of magnetic domain structures.

[0148] Figure 6 and Figure 7 The illustration shows a case where the image acquisition device 30 and the resolution device 40 are different devices, but a system integrating the image acquisition device 30 and the resolution device 40 can also be used.

[0149] As a means of introducing thermal strain onto the surface of the original plate 2, known methods such as laser irradiation, electron beam irradiation, and ion implantation can be used. As a means of forming grooves on the surface of the original plate 2, known methods such as laser irradiation, electron beam irradiation, and machining can be used. The configuration of the laser irradiation device 500 for introducing thermal strain by laser irradiation will be described below.

[0150] Figure 8 The diagram shows the configuration of a laser irradiation device 500. The laser irradiation device 500 includes a polygon mirror 501, a light source device 503, a collimator 505, a condenser lens 507, a motor 509, a sensor 511, a control unit 513, and a through plate device 515.

[0151] The plate-passing device 515 causes the original plate 2 to pass through in the rolling direction RD.

[0152] The polygon mirror 501 is, for example, a regular polygonal prism. Multiple plane mirrors are respectively provided on multiple sides of the polygon mirror 501 that constitute the regular polygonal prism. The laser beam LB is incident from the light source device 503 through the collimator 505 in one direction (horizontal direction) onto the plane mirror of the polygon mirror 501 and is reflected by the plane mirror.

[0153] The polygon mirror 501 can rotate around the rotation axis O1 driven by the motor 509. Depending on the rotation angle of the polygon mirror 501, the incident angle of the laser beam LB relative to the plane mirror changes sequentially. Therefore, the reflection direction of the laser beam LB changes sequentially, enabling it to scan the surface of the original plate 2. Figure 8 The symbol P represents the interval between adjacent magnetic domain control processing lines 11, that is, the irradiation spacing of the laser beam LB.

[0154] Under the control of the control unit 513, the light source device 503 outputs a laser beam LB in a prescribed irradiation mode (e.g., continuous irradiation mode or pulse irradiation mode).

[0155] A condenser lens 507 is disposed in the optical path of the laser beam LB reflected from the polygon mirror 501. The condenser lens 507 constitutes a condenser optical system with a specified focal length. The laser beam LB reflected from the polygon mirror 501 is focused onto the surface of the original plate 2 by the condenser lens 507, thereby introducing thermal strain onto the surface of the original plate 2.

[0156] Motor 509 is connected to polygon mirror 501. Motor 509 rotates and drives polygon mirror 501 under the control of control unit 513.

[0157] Sensor 511 is connected to the drive shaft of motor 509. Sensor 511 detects the rotation angle of the polygon mirror 501 rotated by motor 509. In addition, sensor 511 outputs a signal indicating the detected rotation angle (hereinafter referred to as rotation angle signal) to control unit 513.

[0158] The control unit 513 is composed of a processor. The control unit 513 is connected to the light source device 503, the motor 509, the sensor 511, and the through-plate device 515. The control unit 513 receives speed signal input from the through-plate device 515. Furthermore, the control unit 513 outputs a signal to the motor 509 instructing the rotation drive of the polygon mirror 501.

[0159] Furthermore, the control unit 513 controls the switching on and off of the power of the laser beam LB output by the light source device 503 based on the stress input signal representing the magnetic domain control processing area 21 and the rotation angle signal output from the sensor 511. When the laser irradiation device 500 is electrically connected to the analysis device 40, the stress input signal is input from the analysis device 40 to the laser irradiation device 500. The stress input signal can also be input to the laser irradiation device 500 by the operator.

[0160] (3. Manufacturing method of oriented electromagnetic steel sheet 1)

[0161] Next, the manufacturing method of the orientation-oriented electromagnetic steel sheet 1 according to this embodiment will be described. According to the manufacturing method of the orientation-oriented electromagnetic steel sheet 1 according to this embodiment, the orientation-oriented electromagnetic steel sheet 1 of this embodiment can be suitably manufactured. However, the manufacturing method described below is merely an example of a preferred manufacturing method for the orientation-oriented electromagnetic steel sheet 1 and does not limit the orientation-oriented electromagnetic steel sheet 1. For ease of explanation, the manufacturing apparatus will be appropriately mentioned in the description of the manufacturing method. However, the manufacturing apparatus mentioned below is merely a preferred example for implementing the manufacturing method of the orientation-oriented electromagnetic steel sheet 1 of this embodiment.

[0162] like Figure 9 As shown in the flowchart, the manufacturing method of the orientation-oriented electromagnetic steel sheet 1 in this embodiment includes: step S62, obtaining a magnetic domain image of the original sheet 2 of the orientation-oriented electromagnetic steel sheet 1; step S64, determining based on the distribution of magnetic domain widths in the magnetic domain image. Figure 12 The magnetic domain control processing area 21 shown; and step S66, applying magnetic domain control processing to the magnetic domain control processing area 21 determined based on the distribution of magnetic domain width. Furthermore, in the manufacturing method of the orientation-oriented electromagnetic steel sheet 1 of this embodiment, a rectangular evaluation area is set in the orientation-oriented electromagnetic steel sheet 1, with a side length of 50 mm parallel to the rolling direction RD of the orientation-oriented electromagnetic steel sheet 1 and a side length of 100 mm parallel to the rolling right-angle direction TD of the orientation-oriented electromagnetic steel sheet 1. Furthermore, when imaginary lines VL with a length of 100 mm parallel to the rolling right-angle direction TD are set at 5 mm intervals inside the evaluation area, the standard deviation of the interval between the intersection point of the imaginary line VL and the magnetic domain control processing line 11, i.e., the magnetic domain control point VP, is set to 1.25 mm or more.

[0163] First, obtain the magnetic domain image of the original plate 2 (refer to...). Figure 9 (S62). The original plate 2 refers to the orientation electromagnetic steel plate 1 before the application of magnetic domain control processing. The magnetic domain image can be acquired, for example, by the image acquisition device 30. Then, the distribution of the width of the 180° magnetic domains (magnetic domain width) is derived from the magnetic domain image. The distribution of the magnetic domain width in the original plate 2 can be derived, for example, by using the calculation unit 41 of the analysis device 40.

[0164] Then, regions with a domain width greater than or equal to a specified value (e.g., approximately 500 μm or more) are designated as domain control processing regions 21 (see reference). Figure 9 (S64). Figure 12 The original plate 2 of the orientation-oriented electromagnetic steel plate 1 shown in Figure 1 is illustrated. Figure 12 The shaded area in the image represents the magnetic domain control processing region 21. Additionally, Figure 12The white area in the diagram represents the non-magnetic domain control processing region 22. The magnetic domain width of the magnetic domain control processing region 21 is above a specified value, while the magnetic domain width of the non-magnetic domain control processing region 22 is below a specified value.

[0165] The magnetic domain image displayed on the display unit 45 can also be visually observed by the operator to determine the magnetic domain control processing area 21, and the stress introduction signal representing the magnetic domain control processing area 21 can be input to the laser irradiation device 500.

[0166] Preferably, the domain control strength is determined based on the domain width of the oriented electromagnetic steel sheet before domain subdivision processing. The domain control strength is the amount of thermal strain when the domain control method is thermal strain, and the depth of the groove when the domain control method is a groove. In this case, the maximum value of the tensile strength introduced by thermal strain or the groove depth in the domain control processing line becomes non-uniform at each measurement point of tensile strength or groove depth.

[0167] The greater the intensity of magnetic domain control, the better the effect of magnetic domain subdivision. On the other hand, the greater the intensity of magnetic domain control, the more likely it is to lead to increased hysteresis loss and deterioration of noise characteristics. Furthermore, according to the present inventors' novel insights, the saturation intensity of magnetic domain control varies in oriented electromagnetic steel sheets.

[0168] Domain control saturation intensity refers to the domain control intensity at which the effect of domain subdivision processing becomes saturated. When the domain control intensity is below the domain control saturation intensity, a higher domain control intensity results in lower iron loss. However, when the domain control intensity exceeds the domain control saturation intensity, increasing the domain control intensity does not improve the iron loss reduction effect. Furthermore, even when the domain control intensity exceeds the domain control saturation intensity, a higher domain control intensity leads to increased hysteresis loss and worsened noise characteristics. Therefore, the domain control intensity is ideally located within the range not exceeding the domain control saturation intensity.

[0169] Specifically, it is preferable to perform domain subdivision processing with high domain control intensity in regions with large domain width and small β angle, and to perform domain subdivision processing with low domain control intensity in regions with small domain width and large β angle. In regions with large β angles, no domain control effect is obtained, therefore the domain control saturation intensity is 0. In regions with β angles below a predetermined value, the domain control effect is obtained. For example, when the β angle is below 2°, the domain control effect is presumed to be obtained. Moreover, in regions with β angles below the predetermined value, the larger the β angle, the greater the domain control saturation intensity. Furthermore, in regions with even smaller β angles, the domain control saturation intensity remains approximately constant.

[0170] Figure 18 The diagram illustrates a method for determining the domain control strength based on the domain width. Figure 18The vertical axis represents the domain control strength, and the horizontal axis represents the domain width. Figure 18 The solid line curve represents the domain control saturation intensity. In regions with small domain widths, no domain control effect is achieved, resulting in a domain control saturation intensity of 0. Domain control is achieved in regions with domain widths exceeding 500 μm. Furthermore, in regions with domain widths exceeding 500 μm, the larger the domain width, the greater the domain control saturation intensity. Moreover, in regions with domain widths exceeding approximately 1200 μm, the domain control saturation intensity remains approximately constant.

[0171] Figure 14 The diagram illustrates a method for determining the domain control strength based on the β angle. Figure 14 The vertical axis represents the domain control intensity, and the horizontal axis represents the magnitude of the β angle. Figure 14 The solid line curve represents the domain control saturation intensity. In regions with large β angles, no domain control effect is achieved, therefore the domain control saturation intensity is 0. In regions with β angles below a specified value, the domain control effect is achieved. For example, when the β angle is below 2°, the domain control effect is presumed. Furthermore, in regions with β angles below the specified value, the larger the β angle, the greater the domain control saturation intensity. Moreover, in regions with smaller β angles, the domain control saturation intensity remains approximately constant.

[0172] The optimal relationship between the domain width and the domain control intensity at the site where domain control is implemented is as follows: Figure 14 The curve is on the solid line in the diagram. Alternatively, the optimal relationship between the β angle at the site where domain control is implemented and the domain control intensity is... Figure 14 The solid line on the curve represents the domain control saturation intensity, which can be used as the target value for the domain control intensity.

[0173] Furthermore, there exists a minimum intensity at which the magnetic domain control effect manifests, namely the minimum intensity of magnetic domain control. When performing magnetic domain control, it is further preferred that the magnetic domain control intensity be greater than or equal to the minimum intensity of magnetic domain control.

[0174] However, the domain control intensity can also be slightly uneven relative to the target domain control saturation intensity. Figure 13 and Figure 14 In this context, the region above the minimum domain control intensity and within a certain range of the domain control saturation intensity curve is defined as the target range of domain control intensity. The domain control intensity and the domain width of the domain control target area are preferably within a certain range. Figure 13 and Figure 14 The area within the shaded region surrounded by dashed lines. When the maximum value of the tensile stress in the magnetic domain control processing line, which introduces thermal strain, is not uniform at each tensile stress measurement point, it is preferable to intentionally vary the magnetic domain control intensity. In this case, it is preferable to vary it within the shaded region surrounded by dashed lines.

[0175] When the magnetic domain control processing line is under thermal strain, the magnetic domain control intensity can be varied according to the irradiation conditions of the laser or electron beam. Specifically, the power of the laser or electron beam, the irradiation time, and the irradiation interval can be varied to change the average irradiation energy density Ua (mJ / mm²) per unit area. 2 The depth of the groove formed on the orientation electromagnetic steel plate can be varied by adjusting the time, intensity, shape, etc., of methods such as laser or electron beam irradiation, mechanical processing based on gears, and chemical processing based on etching, when the magnetic domain control processing line is set as a groove.

[0176] Next, magnetic domain control processing is preferentially implemented in the domain control processing region 21 (refer to...). Figure 9 (S66). Preferably, magnetic domain control processing is performed only on the magnetic domain control processing region 21. When the magnetic domain control processing line 11 is under thermal strain, the magnetic domain control processing can be performed by irradiation with a laser beam LB based on the laser irradiation device 500, or by other means such as ion implantation or electron beam irradiation. When the magnetic domain control processing line 11 is a groove, the magnetic domain control processing can also be performed using a tool for machining.

[0177] An example of a method for determining the domain control processing region 21 will be described in detail. The processing for a specific domain control processing region 21 is performed, for example, by the arithmetic unit 41 of the analysis device 40.

[0178] The arithmetic unit 41 uses, for example, a two-dimensional Fourier transform to derive the distribution of magnetic domain widths of the original plate 2. Then, the arithmetic unit 41 determines the regions with magnetic domain widths of a predetermined value or higher (e.g., about 500 μm or more) as the regions for which magnetic domain control processing is preferentially applied.

[0179] Two-dimensional Fourier transform is particularly effective as a means of analyzing the magnetic domain structure of magnetic bodies with periodic magnetic domain structures, such as oriented electromagnetic steel plate 1 and original plate 2. Hereinafter, a method for deriving the distribution of magnetic domain widths of original plate 2 will be explained using a short-term Fourier transform (hereinafter referred to as "ST2DFT"), which is one of the earliest signal processing methods used in the time / frequency analysis of sound signals and is extended to a two-dimensional region.

[0180] The image (magnetic domain image) represented by the image signal acquired by the image acquisition device 30 is labeled as x(k, l) as a data string of two-dimensional coordinates (kl coordinates). In this embodiment, the magnetic domain image to be analyzed is an image binarized with two colors, or an image represented with three or more color levels (multi-level) such as grayscale.

[0181] In order to derive the distribution of the domain width of the original plate 2, the arithmetic unit 41 performs the following processes (A-1), (A-2) and (A-3). (A-1) Processing of cutting out multiple partial regions from magnetic domain images (A-2) Perform ST2DFT processing (A-3) Processing for deriving the distribution of magnetic domain widths

[0182] The following section provides a detailed explanation of the processing of A-1 to A-3.

[0183] (A-1) Processing of cutting out multiple partial regions from magnetic domain images

[0184] To extract multiple regions from the magnetic domain image and analyze their respective frequency structures, the range of the k-direction is set to 0 ≤ k ≤ N. k -1. Set the range of the l-direction to 0 ≤ l ≤ N l The window function Wa(k, l)(N) for a rectangular window of -1 k and N l (where k is a natural number). As a window function Wa(k, l), it can be used with Hamming windows, Hanning windows, Blackman windows, etc.

[0185] The observation position in the data string x(k, l) of the magnetic domain image is represented by the index (n, m), and the displacement of the window function Wa(k, l) in the k and l directions is represented by S. k and S l Time (n, m, S) k S l (where n is an integer), as shown in equation (1), nS is obtained by cutting out the magnetic domain image. k ≤k≤nS k +N k -1, mS l ≤l≤mS l +N l The data string x in the range of -1 is a partial region of the data string. nm (k-nS) k ,l-mS l ).

[0186] [Mathematical Expression 1]

[0187] Figure 10 Examples are shown of partial regions cut from the magnetic domain image G corresponding to the observation positions (n, m) = (1,1), (2,2), (3,3), ..., (P, Q) (P and Q are natural numbers).

[0188] In this embodiment, the range of N for a specific window function Wa(k,l) k and N l These are the parameters corresponding to the number of pixels in the k-direction and the number of pixels in the l-direction of a given region, respectively.

[0189] (A-2) Perform ST2DFT processing

[0190] Define a portion of the data string as x nm (n′, m′) = x nm (k-nS) k ,l-mS l ), for x nm When performing a two-dimensional Fourier transform on (n′, m′), as shown in equation (2), a partial Fourier image X(f) corresponding to a portion of the region at the observation position (n, m) is obtained. k f l (n, m).

[0191] [Mathematical Expression 2]

[0192] Here, f k and f l It is spatial frequency.

[0193] When the spatial frequency f k The resolution is expressed as Δf k , the spatial frequency f l The resolution is expressed as Δf l When, Δf k and Δf l Defined as in equation (3).

[0194] [Mathematical Expression 3]

[0195] Here, Δk and Δl represent the spatial resolution in the k-direction and the spatial resolution in the l-direction of the magnetic domain image, respectively.

[0196] For example, when on Figure 10 The data strings x for each of the shown regions nm (k-nS) k ,l-mS l When performing a two-dimensional Fourier transform, such as Figure 11 As shown, partial Fourier images X(f) are obtained according to each observation position (n, m). k f l (n, m).

[0197] (A-3) Processing for deriving the distribution of magnetic domain widths When a partial Fourier image X(f) is obtained k , f l When (f, n, m), calculate the partial Fourier image X(f) k , f l The coordinates of the peak position of the point (k-component f) at (n,m). k max (n, m) and l component f l max (n, m)). It should be noted that, regarding the derivation of peak positions, the region near k=0 and l=0 is largely dependent on the image contrast, and therefore is excluded.

[0198] Then, based on the resolution of the spatial frequency defined by Equation (3) and the peak position of the points of the partial Fourier image, the distribution L(n, m) of the magnetic domain width is derived as in Equation (4).

[0199] [Mathematical Expression 4]

[0200] Thus, by using ST2DFT, the distribution L(n, m) of the magnetic domain width can be quantitatively derived while preserving the positional information of the magnetic domain image. The above... Figures 4A-4C This represents the analytical result of the domain width derived from ST2DFT.

[0201] Figure 12 The image shows a top view of an example of the original plate 2. Figure 12 The original plate 2 is the material of the oriented electromagnetic steel plate 1 in Figure 1. Figure 12 The diagram shows the domain control processing region 21 and the non-domain control processing region 22 of the original plate 2 based on the domain image. The domain control processing region 21 is a region with a domain width greater than a specified value. The domain control processing region 21 of the original plate 2 roughly corresponds to the region with a small β angle in the orientation-oriented electromagnetic steel plate 1. Similarly, the non-domain control processing region 22 of the original plate 2 roughly corresponds to the region with a large β angle in the orientation-oriented electromagnetic steel plate 1. The non-domain control processing region 22 is a region with a domain width less than the specified value and a large β angle. Figure 12The area not enclosed by the dashed line shown is subjected to magnetic domain control processing. In this case, a rectangular evaluation area is set in the oriented electromagnetic steel sheet 1, with a side length of 50 mm parallel to the rolling direction RD of the oriented electromagnetic steel sheet 1 and a side length of 100 mm parallel to the rolling right-angle direction TD of the oriented electromagnetic steel sheet 1. Furthermore, within the evaluation area, imaginary lines VL, each 100 mm long and parallel to the rolling right-angle direction TD, are set at 5 mm intervals along a direction parallel to the rolling direction. In at least one imaginary line VL, the standard deviation of the interval along the imaginary line VL where the imaginary line VL intersects with the magnetic domain control processing line 11 is set to 1.25 mm or more. Thus, |β... L |The orientation of the electromagnetic steel sheet in Figure 1 is greater than 1.5°.

[0202] When the arithmetic unit 41 derives the domain width distribution L(n, m), the arithmetic unit 41 determines the region with a domain width greater than or equal to a predetermined value as the domain control processing region 21 (i.e., the region where domain control processing is applied). The control unit 513 of the laser irradiation device 500 turns on the power of the laser beam LB to the domain control processing region 21, and preferably controls it to turn off the power of the laser beam LB to the non-domain control processing region 22 (i.e., the region other than the domain control processing region 21). As a result, the domain control processing line 11 is introduced into the domain control processing region 21 of the original board 2. In addition, the introduction of the domain control processing line 11 in the non-domain control processing region 22 of the original board 2 is suppressed to a minimum.

[0203] Through the above steps, a magnetic domain image of the orientation-controlled electromagnetic steel sheet 1 can also be obtained. In the magnetic domain image of the orientation-controlled electromagnetic steel sheet 1, the magnetic domain control processing line 11 is sometimes unclear. In this case, in order to clearly identify the magnetic domain control processing line 11, the observation conditions can be adjusted. For example, by applying a DC magnetic field perpendicular to the surface (thickness direction) of the orientation-controlled electromagnetic steel sheet 1, the magnetic domain control processing line 11 can be made clearer.

[0204] The embodiments of this disclosure have been described above, but this disclosure is not limited thereto, and appropriate modifications can be made without departing from the inventive concept. Hereinafter, a further preferred example of the orientation-oriented electromagnetic steel sheet 1 and its manufacturing method according to this embodiment will be described. Unless otherwise specified, the preferred embodiments described below can be applied to both the orientation-oriented electromagnetic steel sheet 1 and its manufacturing method. As will be described later, the orientation-oriented electromagnetic steel sheet of this embodiment may have a magnesium olivine coating and / or an insulating coating on the surface of the base steel sheet.

[0205] The following will explain each point separately. However, when the oriented electromagnetic steel sheet has a base steel sheet, a forsterite coating, and / or an insulating coating, the following specifications regarding chemical composition, magnetic domain control treatment lines, magnetic domain control regions, and non-magnetic domain control treatment lines pertain to the base steel sheet. However, the specifications regarding sheet thickness apply to the entire oriented electromagnetic steel sheet, including the base steel sheet, the forsterite coating, and / or the insulating coating.

[0206] (Chemical composition and plate thickness)

[0207] The chemical composition of the orientation-oriented electromagnetic steel sheet 1 and the base sheet 2 is not limited, as long as it is equivalent to the known orientation-oriented electromagnetic steel sheet 1. For example, the chemical composition of the orientation-oriented electromagnetic steel sheet 1 and the base sheet 2, by mass%, may contain Si: 2.500~7.000%, Mn: 0.00~1.000%, C: 0~0.085%, acid-soluble Al: 0~0.065%, N: 0~0.012%, Cr: 0~0.300%, Cu: 0~0.400%, P: 0~0.500%, Sn: 0~0.3%. 0.00%, Sb: 0~0.300%, Ni: 0~1.000%, S: 0~0.015%, Se: 0~0.015%, Bi: 0~0.020%, Nb: 0~0.030%, V: 0~0.030%, Mo: 0~0.030%, Ta: 0~0.030%, W: 0~0.030%, B: 0~0.080%, Ti: 0~0.015%. The balance of the chemical composition includes Fe and impurities.

[0208] The thickness of the oriented electromagnetic steel sheet 1 and the original sheet 2 is not limited, but is preferably 0.15 mm to 0.30 mm. By setting it to 0.30 mm or less, classical eddy current losses can be suppressed, further improving iron loss. On the other hand, by making the sheet thickness 0.15 mm or more, rolling efficiency can be improved, thus increasing productivity.

[0209] (Laminated)

[0210] Oriented electromagnetic steel sheet 1 and base sheet 2 may also have a magnesium olivine coating. Additionally, oriented electromagnetic steel sheet 1 and base sheet 2 may also have an insulating coating. The magnesium olivine coating and the insulating coating may be formed on one side or both sides of the oriented electromagnetic steel sheet 1.

[0211] Forsterite coatings are, for example, inorganic coatings with magnesium silicate as the main component. Forsterite coatings are formed, for example, by reacting an annealing release agent containing magnesium oxide (MgO) applied to the surface of a base steel sheet with the surface composition of the base steel sheet during final annealing. For example, a forsterite coating has a composition derived from the annealing release agent and the base steel sheet (more specifically, a composition with Mg2SiO4 as the main component). On the other hand, when an annealing release agent mainly composed of Al2O3 is used in the final annealing, a forsterite coating sometimes does not form.

[0212] The insulating coating imparts electrical insulation and tensile strength to the oriented electromagnetic steel sheet 1. By applying tension to the oriented electromagnetic steel sheet 1, the movement of magnetic domain walls within the sheet becomes easier, thereby reducing iron loss. Furthermore, the insulating coating can impart various properties to the oriented electromagnetic steel sheet 1, such as corrosion resistance, heat resistance, and slip resistance. The insulating coating can be, for example, a known coating formed by applying a coating solution primarily composed of phosphate and colloidal silica to the surface of a magnesium olivine coating and then sintering it.

[0213] The insulating coating is preferably formed after final annealing and after the magnetic domain control treatment. Alternatively, the insulating coating may be formed after the final annealing process and before the magnetic domain control treatment. In the case where the insulating coating is formed before the magnetic domain control treatment, the insulating coating may sometimes peel off in the magnetic domain control treatment line 11. Therefore, it is preferable to form the insulating coating again on the magnetic domain control treatment line 11 after the magnetic domain control treatment.

[0214] (The angle between the magnetic domain control processing line 11 and the rolling right-angle direction TD)

[0215] The angle between the magnetic domain control processing line 11 and the rolling right-angle direction TD is not particularly limited.

[0216] On the other hand, such as Figure 1A As illustrated, the angle between the domain control processing line 11 and the rolling right-angle direction TD needs to exceed 0°. For example, the angle between the domain control processing line 11 and the rolling right-angle direction TD can be set to any value within the range of 0° to 45°. Alternatively, the angle between the domain control processing line 11 and the rolling right-angle direction TD can be set to 2° or more, 3° or more, or 5° or more. Or, the angle between the domain control processing line 11 and the rolling right-angle direction TD can be set to less than 40°, less than 35°, or less than 30°.

[0217] like Figure 1AAs illustrated, the angles formed by all the domain control processing lines 11 and the rolling right-angle direction TD can be the same. That is, all the domain control processing lines 11 can extend parallel to each other. On the other hand, the angles formed by the domain control processing lines 11 and the rolling right-angle direction TD can be uneven. That is, some or all of the multiple domain control processing lines 11 can extend non-parallel to each other. The average value of the angles formed by the domain control processing lines 11 and the rolling right-angle direction TD can also be set to 2° or more, 3° or more, or 5° or more. The average value of the angles formed by the domain control processing lines 11 and the rolling right-angle direction TD can also be set to 40° or less, 35° or less, or 30° or less. The average value of the angle is calculated by measuring the angles formed by one domain control processing line and the rolling right-angle direction TD at multiple locations, or by measuring the angles formed by multiple domain control processing lines and the rolling right-angle direction TD at one or more locations, and then calculating the average value.

[0218] (Interval P of magnetic domain control processing)

[0219] For example, by Figure 8 The interval P of the magnetic domain control process, determined by the irradiation distance P of the laser beam LB shown, is not particularly limited. A smaller interval P results in better iron loss reduction. Conversely, a larger interval P improves noise characteristics. The interval can be appropriately selected to correspond to the characteristics required by the oriented electromagnetic steel sheet 1.

[0220] The interval P for implementing the magnetic domain control processing corresponds to the interval between the magnetic domain control processing line 11 in the orientation-oriented electromagnet 1 of this embodiment and the imaginary line along the magnetic domain control processing line 11. The interval P for the magnetic domain control processing is specified by measuring the interval between the imaginary lines along the magnetic domain control processing line 11 provided on the orientation-oriented electromagnet 1, which are set throughout the entire width of the orientation-oriented electromagnet 1.

[0221] For example, the interval P of the magnetic domain control processing can be set to 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, or 5.0 mm or more. Alternatively, the interval P of the magnetic domain control processing can be set to 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, or 7.0 mm or less. The interval P of the magnetic domain control processing is a value measured along the rolling direction RD. Figure 8 In order to simplify the illustration, the domain control processing line 11 is depicted as being approximately parallel to the rolling right-angle direction, but in reality, as previously explained, it is inclined at a specified angle relative to the rolling right-angle direction TD.

[0222] exist Figure 1AIn the illustrated orientation-oriented electromagnetic steel sheet 1, the interval P of the magnetic domain control processing is constant. On the other hand, the interval P of the magnetic domain control processing can also be non-uniform. For example, the average value of the interval P of the magnetic domain control processing can be set to 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, or 5.0 mm or more. The average value of the interval P of the magnetic domain control processing can also be set to 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, or 7.0 mm or less.

[0223] (The magnitude of the tensile stress introduced in thermal strain)

[0224] The magnetic domain control processing line 11 can also be thermal strain. In thermal strain, tensile stress is introduced. The greater the tensile stress, the better the effect of improving iron loss. On the other hand, the smaller the tensile stress, the better the noise characteristics. The tensile stress can be appropriately selected to correspond to the characteristics required by the oriented electromagnetic steel sheet 1.

[0225] The magnitude of the tensile stress is not particularly limited. For example, in at least a portion of the magnetic domain control processing line 11, the tensile stress relative to any direction is preferably 40 MPa or more, 60 MPa or more, or 80 MPa or more. If the tensile stress relative to at least one direction is 40 MPa or more, it is considered to satisfy the requirement of "tensile stress of 40 MPa or more". Furthermore, for example, in at least a portion of the magnetic domain control processing line 11, the tensile stress relative to any direction is preferably 300 MPa or less, 200 MPa or less, 180 MPa or less, or 150 MPa or less. The tensile stress relative to any direction in the magnetic domain control processing line 11 can be the same or non-uniform.

[0226] (Depth and width of the groove)

[0227] The magnetic domain control processing line 11 can also be a slot. The greater the depth and width of the slot, the better the effect of improving iron loss. On the other hand, the smaller the depth and width of the slot, the better the noise characteristics. The shape of the slot can be appropriately selected to correspond to the characteristics required by the oriented electromagnetic steel sheet 1.

[0228] There is no particular limitation on the depth of the groove; for example, it is preferably set to 5μm to 50μm. The depth of the groove can also be set to 6μm or more, 7μm or more, or 10μm or more. Alternatively, the depth of the groove can be set to less than 48μm, 45μm or less, or 40μm or less.

[0229] The width of the groove (the width of the opening) is not particularly limited, but is preferably set to 10μm to 300μm. The groove width can also be specified as 20μm or more, 30μm or more, or 50μm or more. Alternatively, the groove width can be specified as 280μm or less, 250μm or less, or 200μm or less. The depth and width of the groove can be the same or uneven. In the case of unevenness, it is preferable that the average depth and width of multiple grooves fall within the above-mentioned range.

[0230] (Determination Method)

[0231] The following describes the method for measuring various parameters of the orientation-oriented electromagnetic steel sheet 1 according to this embodiment. The measurement of any parameter is performed on a sample taken from the orientation-oriented electromagnetic steel sheet 1. For example, a rectangular sample with a length of 100 mm (or more) on both sides can be cut from the orientation-oriented electromagnetic steel sheet 1 for measurement. When the orientation-oriented electromagnetic steel sheet 1 is a coil, the sample can be taken from any part of the coil. Furthermore, when the orientation-oriented electromagnetic steel sheet 1 is a component assembled into a transformer, motor, or other motor product, the sample can be taken from any part of the component. When the component is small, if the length of one side of the sample along the rolling right-angle direction TD is 100 mm or more, then the length of one side of the sample along the rolling direction RD can be 50 mm or more and less than 100 mm. In this case, to minimize the influence of mechanical strain, etc., on the sample, it is preferable to take the sample by methods such as wire cutting.

[0232] (Specific method of magnetic domain control processing line 11)

[0233] When the domain control processing line 11 is a slot, the domain control processing line 11 can be identified by visual inspection. When the oriented electromagnetic steel sheet 1 has an insulating film, the domain control processing line 11 can be visually identified by removing the insulating film using a known stripping agent.

[0234] When the domain control processing line 11 is subjected to thermal strain, it may sometimes be impossible to identify visually. In such cases, for example, using... Figure 5 The image acquisition device 30, as illustrated, captures images of magnetic domains. As needed, a DC magnetic field is applied along the normal direction ND of the rolled surface of the oriented electromagnetic steel sheet 1 while capturing the magnetic domain images. By observing the magnetic domain images, the location of thermal strain can be determined.

[0235] (Specific methods for rolling direction RD and rolling right angle direction TD)

[0236] The rolling direction RD and the rolling right-angle direction TD of the orientation-oriented electromagnetic steel sheet 1 are specified by the means listed below.

[0237] (1) When the sample is cut from a coil of oriented electromagnetic steel sheet 1, the width direction of the coil is regarded as the rolling right-angle direction TD. In addition, the direction perpendicular to the rolling right-angle direction TD and the rolling surface normal direction ND is regarded as the rolling direction RD.

[0238] (2) In the case where the sample is cut from a component of an electric motor product, the rolling direction RD and the rolling right-angle direction TD are determined based on the rolling marks on the surface of the oriented electromagnetic steel sheet 1. The direction of extension of the rolling marks is regarded as the rolling direction RD. The direction perpendicular to the rolling direction RD and the normal direction ND of the rolling surface is regarded as the rolling right-angle direction TD.

[0239] (3) When it is difficult to specify the rolling direction RD and the rolling right-angle direction TD based on the surface marks of the oriented electromagnetic steel sheet 1, the rolling direction RD and the rolling right-angle direction TD are specified based on the crystal orientation of the oriented electromagnetic steel sheet 1. Specifically, the crystal orientation of the oriented electromagnetic steel sheet 1 to be evaluated is measured at multiple points. Moreover, the easy magnetization axis at which the crystal orientation at the measurement point forms an angle with the normal direction ND (thickness direction) of the rolling surface is closest to a right angle is selected. <001> The direction with the smallest offset angle is considered as the rolling direction RD, and the direction perpendicular to the rolling direction RD and the normal direction ND of the rolling surface is considered as the rolling right-angle direction TD.

[0240] (Standard deviation of the interval of domain control points VP)

[0241] The standard deviation of the domain control point spacing is calculated according to the following steps. First, a rectangular evaluation area is defined in the oriented electromagnetic steel sheet 1, with a side length of 50 mm parallel to the rolling direction RD of the oriented electromagnetic steel sheet 1 and a side length of 100 mm parallel to the rolling right-angle direction TD of the oriented electromagnetic steel sheet 1. Then, within the evaluation area, imaginary lines VL, parallel to the rolling right-angle direction TD and with a length of 100 mm, are defined on the surface of the oriented electromagnetic steel sheet 1 at 5 mm intervals. Next, the domain control point VP is designated as the intersection of the imaginary line VL and the domain control processing line 11. The designation of the rolling right-angle direction TD and the domain control processing line 11 is performed in the order described above. Then, the spacing between adjacent domain control points VP is measured, and the standard deviation of these measurements is calculated.

[0242] There are no limitations on the location where the evaluation area and the hypothetical line VL are set. The hypothetical line VL can be set in any location where the standard deviation of the interval of the domain control points VP is within the range of this disclosure. For example, the hypothetical line VL can be set in a region X where no domain control processing line 11 is set. On the other hand, if no location is found where the standard deviation of the interval of the domain control points VP can be set to that of the hypothetical line VL within the range of this disclosure, it is presumed that the requirements of this disclosure are not met.

[0243] (Minimum value D of the interval of the domain control points VP) S and maximum value D L )

[0244] Minimum value D of the interval between magnetic domain control processing points S and maximum value D L The calculation is performed according to the following steps. First, the imaginary line VL is set on the surface of the oriented electromagnetic steel sheet 1. Next, the domain control point VP is specified as the intersection of the imaginary line VL and the domain control processing line 11. The rolling direction RD and the domain control processing line 11 are specified in the order described above. Then, the intervals between adjacent domain control points VP are measured, and the minimum and maximum values ​​of these measured values ​​are determined.

[0245] (Method for measuring the β angle)

[0246] The β angle is determined using the side reflection Laue method. The side reflection Laue method is widely known as a method for determining crystal orientation. The β angle is obtained by rounding the measured value to the second decimal place. That is, the significant figures of the β angle are set to the first decimal place.

[0247] (|β) L | and |β S |)

[0248] |β L The following steps are used to determine this. First, using the method described above, the interval is specified as the maximum value D in the imaginary line VL. L Two adjacent domain control points VP. From the midpoint P of the domain control points VP. βL The β angle between these domain control points VP is determined using the method described above, with a 1mm interval. Occasionally, more than two intervals D are formed in a single imaginary line VL. L The location. In this case, the interval becomes the maximum value D. L There are two or more sets of two adjacent domain control points VP. In this case, the midpoint P of the domain control point VP... βL Starting with measuring the β angle between each adjacent domain control point VP at 1 mm intervals, the average of the absolute values ​​of their β angles is taken as the |β| in the imaginary line VL. L That's it.

[0249] |β S The determination order of |β L | Same. First, using the method described above, the interval is specifically defined as the minimum value D in the imaginary line VL. S Two adjacent domain control points VP. From the midpoint P of the domain control points VP. βSThe β angle between these domain control points VP is determined using the method described above, with a 1mm interval. It should be noted that, occasionally, more than two intervals D are formed within a single imaginary line VL. S The location. In this case, the interval becomes the minimum value D. S There are two or more sets of two adjacent domain control points VP. In this case, the midpoint P of the domain control point VP... βS Starting with measuring the β angle between each adjacent domain control point VP at 1 mm intervals, the average of the absolute values ​​of their β angles is taken as the |β| in the imaginary line VL. S That's it.

[0250] Find |β| for each of the multiple imaginary lines VL. L In more than one imaginary line VL, the standard deviation of the spacing between the domain control points is greater than or equal to 1.25 mm and |β L When the angle is 1.5° or higher, it is considered to be an orientation-oriented electromagnetic steel sheet of this disclosure. The more imaginary lines VL that satisfy the requirements of this disclosure, the more preferred.

[0251] (Method for determining the chemical composition of original plate 2 and oriented electromagnetic steel plate 1)

[0252] The chemical composition of the orientation-oriented electromagnetic steel sheet 1 and the original sheet 2 can be determined using general analytical methods for steel. For example, the chemical composition can be determined using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Specifically, a test piece is taken from the center of the sample along its thickness direction, and the chemical composition of the orientation-oriented electromagnetic steel sheet 1 and the original sheet 2 can be determined using a Shimadzu ICPS-8100 (measuring device) under conditions based on a pre-prepared standard curve. The contents of C and S, which are difficult to determine in ICP-AES, can be determined using the combustion-infrared absorption method. The N content can be determined using the inactive gas melting-thermal conductivity method.

[0253] When a magnesium olivine coating and / or an insulating coating are formed on the oriented electromagnetic steel sheet 1 and the original sheet 2, the chemical composition of the oriented electromagnetic steel sheet 1 and the original sheet 2 can be analyzed after removing the magnesium olivine coating and / or the insulating coating from the oriented electromagnetic steel sheet 1 and the original sheet 2.

[0254] For example, forsterite coatings can be removed by immersing the sample in sulfuric acid followed by nitric acid. Appropriate adjustments to the temperature and concentration of the sulfuric and nitric acids, as well as the immersion time, are necessary to prevent excessive dissolution of the iron-based components in the sample. An example of the conditions for removing forsterite coatings is as follows: First, immerse the sample in 10% sulfuric acid at 80°C for 3 minutes. Then, wash the surface of the sample with water using a rag or similar material to remove any adhering residue. Next, allow the sample to dry. Then, immerse the sample in 10% nitric acid at room temperature for approximately 5 seconds while stirring.

[0255] Insulating coatings can be removed, for example, by immersing the sample in a sodium hydroxide solution, followed by immersion in dilute sulfuric acid and nitric acid. The temperature and concentration of the sodium hydroxide, dilute sulfuric acid, and nitric acid solutions, as well as the immersion time, should be appropriately adjusted to prevent excessive dissolution of the iron-based components of the sample. An example of the conditions for removing insulating coatings is as follows.

[0256] First, immerse the sample in a 20% sodium hydroxide solution at 80°C for 15 minutes. Then, allow the sample to dry. Next, immerse the sample in a 10% dilute sulfuric acid solution at 80°C for 4 minutes. Then, remove any residue adhering to the sample surface with a rag or similar cloth. Finally, immerse the sample in a 10% nitric acid solution at room temperature for approximately 10 seconds while stirring.

[0257] (Method for determining the angle between the magnetic domain control processing line 11 and the rolling right-angle direction TD)

[0258] The angle between the domain control processing line 11 and the rolling right-angle direction TD can be measured using a known angle measurement method after specifying the domain control processing line 11 and the rolling right-angle direction TD in the above order.

[0259] (Method for determining the interval P of magnetic domain control processing)

[0260] The interval P of the domain control processing is obtained by first specifying the domain control processing line 11 and the rolling direction RD in the order described above, then setting an imaginary line along the domain control processing line 11, and measuring the interval of the imaginary line using a known length measurement method.

[0261] (Method for determining the magnitude of tensile stress introduced into thermal strain)

[0262] The magnitude of the tensile stress introduced in the thermal strain was determined using the EBSD Wilkinson method and the Cross Court manufactured by BLG Vantage. The EBSD Wilkinson method is described in detail in AJ Wilkinson, et al. "High-resolution elastic strain measurement from electron backscatter diffraction patterns: New levels of sensitivity" Ultramicroscopy Vol 106, No.4-5, March 2006, pp.307-313.

[0263] When determining the magnitude of the tensile stress introduced during thermal strain using the EBSD Wilkinson method and the Cross Court manufactured by BLG Vantage, the magnetic domain control processing line 11 is first specified according to the steps described above. Next, the orientation-oriented electromagnetic steel sheet 1 is cut through the magnetic domain control processing line 11 and perpendicular to it.

[0264] The cut surface is used as the measurement surface. For the cross section containing the magnetic domain control processing line 11 within the measurement surface, analysis is performed using the EBSD Wilkinson method and the Cross Court manufactured by BLG Vantage to extract the tensile stress components relative to any direction and determine their magnitude. For example, it is possible to extract the tensile stress components in the rolling surface normal direction (ND), the direction parallel to the magnetic domain control processing line 11, and the direction perpendicular to both the rolling surface normal direction (ND) and the magnetic domain control processing line 11.

[0265] The number of measurement sites is, for example, 10. If, at least one site on the orientation-oriented electromagnetic steel sheet 1, the tensile stress in any direction is 40 MPa or more (i.e., the tensile stress in at least one direction is 40 MPa or more), it is determined that the maximum value of the tensile stress in any direction within the magnetic domain control processing lines of the orientation-oriented electromagnetic steel sheet 1 is 40 MPa or more. Therefore, if the purpose is to determine whether the maximum value of the tensile stress is 40 MPa or more, the measurement of the tensile stress can be stopped when a measurement point where the tensile stress in any direction is found to be 40 MPa or more. However, after calculating σ(TS) as described later... m ) 2 TS m（β<2） or TS m（β≥2） In the case of [unspecified condition], the measurement is not interrupted, and the tensile stress at each measurement point is calculated.

[0266] (Methods for measuring the depth and width of the groove)

[0267] The depth and width of the groove can be determined by using a known three-dimensional measuring machine to measure the surface shape of a specific sample. In the case where the oriented electromagnetic steel sheet 1 has an insulating coating, the three-dimensional measurement of the sample surface is performed after removing the insulating coating according to the steps described above.

[0268] Example

[0269] The effects of one aspect of this disclosure are further illustrated through the examples. However, the conditions in the examples are merely examples used to confirm the feasibility and effects of implementing this disclosure. This disclosure is not limited to this single example of conditions. Various conditions can be used to achieve the purpose of this disclosure as long as they do not depart from its main theme.

[0270] (Example 1)

[0271] Oriented electromagnetic steel sheets from the same batch with a thickness of 0.20 mm were used as the base plates. Magnetic domain control treatment was applied to the base plates under the various conditions shown in Table 1.

[0272] Regarding the steel plates No. 1 to 13 obtained through each treatment, the number of VL (imaginary lines) with a standard deviation of 1.25 mm or more is shown in column A of Table 1. Further, the VLs shown in column A will satisfy |β... L The number of VLs with a relationship ≥ 1.5° is shown in column B of Table 1. Column C of Table 1 shows the VLs that further satisfy 2 ≤ D in column B. L / D S The number of VLs for the relationship is shown in column D of Table 1, and the VLs shown in column C further satisfy 0.5゜<|β. L |-|β S | The number of VLs in the relationship. Standard deviation and |β L |、|β S The determination of | is performed according to the steps described above. A rectangular sample with two sides of length 100 mm is cut from the three-phase transformer core used for the noise and iron loss determination (described later) for measurement. Within this rectangular sample, a rectangular evaluation area is defined, with a side length of 50 mm parallel to the rolling direction RD and a side length of 100 mm parallel to the rolling right-angle direction TD. Inside the evaluation area, imaginary lines VL, each 100 mm long and parallel to the rolling right-angle direction TD, are set at 5 mm intervals. There are 9 imaginary lines VL.

[0273] Table 1 shows samples No. 1 to 10, which have straight domain control lines formed in a wide domain width region. Sample No. 11 has straight domain control lines covering the entire width. Sample No. 12 has regularly formed dashed domain control lines. Sample No. 13 has randomly formed dashed domain control lines. Regarding No. 14, a sample has curved linear domain control lines formed in a wide domain width region. Sample No. 15 has domain control lines formed only in a region within ±4 mm of the center of each grain's rolling direction RD, spaced 4 mm apart. The radius of curvature of the steel plate at the original location of this grain during final annealing is 250 mm.

[0274] Table 1 shows that the average irradiation energy density of the specimens subjected to thermal strain at 4 mm intervals was 1.5 mJ / mm². 2 The laser beam is used for magnetic domain control processing.

[0275] Table 1 shows the sample forming a groove (depth: 15 μm, width: 20 μm) for magnetic domain control.

[0276] The mixing shown in Table 1 refers to the domain control processing conditions in which the aforementioned thermal strain and the total length of the aforementioned groove are made in a 1:1 ratio.

[0277] Next, for the orientation electromagnetic steel plates that have undergone the aforementioned magnetic domain control treatment, their noise and iron loss were measured, and the measurement results are recorded in Table 2.

[0278] The methods for measuring noise and iron loss are as follows. First, 205 sheets of 0.20mm thick oriented electromagnetic steel plates were stacked to fabricate a three-phase transformer core. The width of the legs and yoke of the three-phase transformer core was 150mm. The height and width of the three-phase transformer core were both 750mm. The noise and iron loss of these three-phase transformer cores were measured. The measurement conditions were set as follows: frequency: 50Hz and excitation flux density: 1.8T.

[0279] During noise measurement, microphones were placed at equal intervals at eight locations around the transformer where the three-phase transformer core was assembled. The distance between the transformer and the microphones was set to 30 cm. The noise measurement results from these microphones were corrected for A-characteristics and averaged to obtain the noise evaluation results (in dBA) for the oriented electromagnetic steel sheet, which are recorded in Table 3. Examples with noise evaluation results of 43.50 dBA or less were judged as examples of achieving low noise. In Table 2, noise evaluation results judged as unqualified are marked with an underline.

[0280] As described above, the iron loss was determined by measuring the voltage and current on the primary and secondary sides using a power analyzer when energized at a frequency of 50 Hz and an excitation flux density of 1.8 T. The calculated iron loss, as the iron loss evaluation results (in W / kg) for oriented electromagnetic steel sheets, is recorded in Table 3. Examples with an iron loss evaluation result of 1.270 W / kg or less were identified as examples that achieved low iron loss.

[0281]

[0282]

[0283] The samples No. 1~3 and 14 shown in Table 2 are the average absolute values ​​of the intersection points of the imaginary line and the domain control processing line, i.e., the intervals between the domain control points, with a standard deviation of 1.25 mm or more. L |For samples with an angle greater than 1.5°.

[0284] In contrast, sample No. 11 underwent domain control treatment across its entire width, resulting in good iron loss, but deteriorated noise characteristics. Sample No. 12, with its dotted-line domain control treatment, showed improved noise compared to sample No. 11, but both iron loss and noise characteristics failed to meet standards. Sample No. 13, with its random dotted-line domain control treatment, achieved further improvement in noise compared to sample No. 12, but its iron loss characteristics still failed to meet standards.

[0285] For No.15, since magnetic domain control is only performed on the central region of each grain in the rolling direction, the noise is within the preferred range, but the iron loss characteristics are unacceptable.

[0286] Samples No. 4 and 5, based on meeting the conditions satisfied by samples No. 1 to 3 above, have a standard deviation of at least 1.25 mm between the magnetic domain control points on two or more imaginary lines spaced 5 mm apart, and the average absolute value of the aforementioned β angle |β L The iron loss of samples No. 4 and No. 5 is better than that of samples No. 1 and No. 2, and they also have the same excellent characteristics as samples No. 1 and No. 2 in terms of noise.

[0287] Sample No. 6 satisfies the conditions met by samples No. 1 to 3 above, and D L / D S The sample with a score of 2 or higher. The iron loss of sample No. 6 is also considered excellent among samples No. 1 to 3, and the noise of sample No. 6 is also considered excellent among samples No. 1 to 3. Sample No. 6 can be evaluated as having superior characteristics in both iron loss and noise.

[0288] Sample No. 7 satisfies the conditions satisfied by No. 4 and No. 5, and D L / D S The sample with a value of 2 or higher. The iron loss and noise of sample No. 7 were superior to those of samples No. 1 to 3.

[0289] Sample No. 8 satisfies the conditions met by samples No. 1 to No. 3, and also satisfies 0.5° ≤ |β|. L |-|β S The relationship between the samples was analyzed. Sample No. 8 exhibited superior iron loss and noise characteristics compared to samples No. 1 through No. 3.

[0290] The No. 9 sample is a sample that satisfies the conditions of both the No. 6 and No. 8 samples.

[0291] The iron loss and noise of sample No. 9 were superior to those of samples No. 1 to No. 3.

[0292] Sample No. 10 satisfies all the conditions met by samples No. 7 and 8. Sample No. 10 exhibits superior iron loss and noise characteristics compared to samples No. 7 through 9.

[0293] (Example 2) Oriented electromagnetic steel sheets from the same batch with a thickness of 0.20 mm were used as the base plates. Magnetic domain control treatment was applied to the base plates under the various conditions shown in Table 3.

[0294] Regarding the steel plates No. 16~23 obtained through each treatment, the number of VL (imaginary lines) with a standard deviation of 1.25 mm or more is shown in column A of Table 1. Further, the VLs shown in column A will satisfy |β... L The number of VLs with a relationship ≥ 1.5° is shown in column B of Table 1. Column C of Table 1 shows that the VLs shown in column B further satisfy 4 ≤ D. L / D S The number of VLs for the relationship is shown in column D of Table 1, and the VLs shown in column C further satisfy 0.5゜<|β. L |-|β S | The number of VLs in the relationship. Standard deviation and |β L |、|β SThe determination of | is performed according to the steps described above. A rectangular sample with two sides of length 100 mm is cut from the three-phase transformer core used for the noise and iron loss determination (described later) for measurement. Within this rectangular sample, a rectangular evaluation area is defined, with a side length of 50 mm parallel to the rolling direction RD and a side length of 100 mm parallel to the rolling right-angle direction TD. Inside the evaluation area, imaginary lines VL, each 100 mm long and parallel to the rolling right-angle direction TD, are set at 5 mm intervals. There are 9 imaginary lines VL.

[0295] The samples No. 16 to 22 shown in Table 3 are samples in which straight magnetic domain control processing lines are formed in a region with a wide magnetic domain width. The sample No. 23 is a sample in which linear magnetic domain control processing lines containing curves are formed in a region with a wide magnetic domain width.

[0296] Table 3 shows that the average irradiation energy density of the specimens subjected to thermal strain at 4 mm intervals was 1.5 mJ / mm². 2 The laser beam is used for magnetic domain control processing.

[0297] Table 3 shows the sample forming a groove (depth: 15 μm, width: 20 μm) for magnetic domain control.

[0298] The mixing shown in Table 3 refers to the domain control processing conditions in which the aforementioned thermal strain and the total length of the aforementioned groove are made in a 1:1 ratio.

[0299] Regarding the orientation electromagnetic steel plates that have undergone the aforementioned magnetic domain control treatment, their noise and iron loss were measured using the same method as in Example 1, and the measurement results are recorded in Table 4.

[0300]

[0301]

[0302] As shown in Tables 3 and 4, in at least one of the aforementioned imaginary lines, D L / D S In these examples with a score of 4 or higher, superior characteristics in terms of iron loss and noise were achieved compared to the example of Example 1.

[0303] (Example 3)

[0304] Oriented electromagnetic steel sheets from the same batch with a thickness of 0.20 mm were used as the base plates. Magnetic domain control treatment was applied to the base plates under the various conditions shown in Table 5.

[0305] Regarding the steel plates No. 24~61 obtained through various treatments, the number of VL (imaginary lines) with a standard deviation of 1.25 mm or more is shown in column A of Table 1. Further, the VLs shown in column A will satisfy |β...L The number of VLs with a relationship ≥ 1.5° is shown in column B of Table 1. Column C of Table 1 shows that the VLs shown in column B also satisfy 2 ≤ D. L / D S The number of VLs for the relationship is shown in column D of Table 1. Among the VLs shown in column B, 4 ≤ D is also satisfied. L / D S The number of VLs for the relationship is shown in column E. Among the VLs shown in column C, 0.5 < |β| also satisfies this condition. L |-|β S The number of VLs with the relationship | is shown in column F. The VLs shown in column D also satisfy 0.5 ゜ < |β. L |-|β S | The number of VLs in the relationship. Standard deviation and |β L |、|β S The determination of | is performed according to the steps described above. A rectangular sample with two sides of length 100 mm is cut from the three-phase transformer core used for the noise and iron loss determination (described later) for measurement. Within this rectangular sample, a rectangular evaluation area is defined, with a side length of 50 mm parallel to the rolling direction RD and a side length of 100 mm parallel to the rolling right-angle direction TD. Inside the evaluation area, imaginary lines VL, each 100 mm long and parallel to the rolling right-angle direction TD, are set at 5 mm intervals. There are 9 imaginary lines VL.

[0306] The samples No. 24 to 61 shown in Table 5 are samples in which straight magnetic domain control processing lines were formed in the region with a wide magnetic domain width.

[0307] Table 5 shows that the average irradiation energy density of the specimens subjected to thermal strain in a linear pattern at 4 mm intervals was 0.5 mJ / mm². 2 ~4.0mJ / mm 2 The laser beam is used for magnetic domain control processing.

[0308] Table 5 shows the sample forming grooves (depth: 15μm~41μm, width: 20μm) for magnetic domain control.

[0309] Regarding the orientation electromagnetic steel plates that have undergone the aforementioned magnetic domain control treatment, their noise and iron loss were measured using the same method as in Example 1, and the measurement results are recorded in Table 6.

[0310]

[0311]

[0312] According to Tables 5 and 6, when σ(TS) is satisfied... m ) 2>5.0, TS m（β<2） >TS m（β≥2） σ(D) m ) 2 >3.0 and / or D m（β<2） >D m（β≥2） In these examples, superior characteristics are obtained in terms of iron loss and noise compared to the example of Example 1.

[0313] Industrial availability According to this disclosure, a oriented electromagnetic steel sheet capable of achieving both low iron loss and low noise, and a method for manufacturing the same, can be provided. Therefore, it has high potential for industrial application.

[0314] Explanation of reference numerals in the attached figures RD rolling direction TD rolling right-angle direction ND (Normal direction of the rolled surface) VL Imaginary Line VP domain control point D L Maximum value of the interval between domain control points D S Minimum value of the interval between domain control points P βL Midpoint of two magnetic domain control points with a maximum interval P βS Midpoint of two magnetic domain control points with the minimum interval X Areas without domain control processing lines 1. Oriented Electromagnetic Steel Sheet 2 original boards 11 Magnetic Domain Control Processing Line 21 Magnetic domain control processing area 22 Non-magnetic domain control processing region 30 Image Acquisition Device 31 Light Source Section 33 MO sensor 35 Image Sensor 37. Signal Processing Department 40 Analysis device 41. Arithmetic Unit 43 Memory 45 Display Section 47 Input Section 49 Communication I / F 500 laser irradiation device 501 Multifaceted Mirror 503 Light Source Device 505 Collimator 507 Condensing Lens 509 Motor 511 sensor 513 Control Department 515 Through-plate device

Claims

1. A type of oriented electromagnetic steel sheet, wherein multiple magnetic domain control lines are present on its surface, wherein, In the oriented electromagnetic steel sheet, a rectangular evaluation area is defined with a side length of 50 mm parallel to the rolling direction and a side length of 100 mm parallel to the rolling right-angle direction. Furthermore, within this evaluation area, imaginary lines of 100 mm length parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. In at least one of the hypothetical lines, the standard deviation of the interval between the intersection points of the hypothetical line and the domain control processing line, i.e., the domain control points, is greater than 1.25 mm, and the interval becomes the maximum value D. L The average of the absolute values ​​of the β angle measured between the two domain control points |β L | is above 1.5°.

2. The oriented electromagnetic steel sheet according to claim 1, wherein, In each of the two or more imaginary lines, the standard deviation of the interval between the domain control points is 1.25 mm or more, and the interval becomes the maximum value D. L The average of the absolute values ​​of the β angle measured between the two domain control points |β L | is above 1.5°.

3. The oriented electromagnetic steel sheet according to claim 1 or 2, wherein, The maximum value D of the interval of the domain control points L The minimum value D of the interval between the magnetic domain control point and the magnetic domain control point S The ratio of D L / D S It is 2 or higher.

4. The oriented electromagnetic steel sheet according to claim 3, wherein, The D L / D S The value is 4 or higher.

5. The oriented electromagnetic steel sheet according to claim 3 or 4, wherein, The |β L | and at the interval where the minimum value D is... S The average of the absolute values ​​of the β angle measured between the two domain control points |β S | Satisfies the following formula, 0.5°≤|β L |-|β S |。 6. The oriented electromagnetic steel sheet according to any one of claims 1 to 5, wherein, The magnetic domain control processing line is thermal strain.

7. The oriented electromagnetic steel sheet according to claim 6, characterized in that, The maximum value of the tensile stress introduced by the thermal strain in the magnetic domain control processing line is not uniform at each of the tensile stress measurement points.

8. The oriented electromagnetic steel sheet according to claim 7, characterized in that, A rectangular evaluation area with a length of 50 mm parallel to the rolling direction and a length of 100 mm parallel to the rolling right-angle direction of the oriented electromagnetic steel sheet is defined on the surface. Furthermore, within the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. The intersection points of the imaginary line and the multiple magnetic domain control processing lines are respectively designated as magnetic domain control points. The maximum value of the tensile stress measured at each of the magnetic domain control points, in units of MPa, is set as TS. m The TS m Let the variance be σ(TS) m ) 2 hour, Satisfying σ(TS) m ) 2 >5.

0.

9. The orientation-oriented electromagnetic steel sheet according to claim 7 or 8, characterized in that, The arithmetic mean of the maximum tensile stress (in MPa) measured at each domain control point with a β angle less than 2°, incorporating the thermal strain, is denoted as TS. m（β<2） The arithmetic mean of the maximum tensile stress measured at each of the domain control points with a β angle of 2° or greater, in units of MPa, which incorporates the thermal strain, is set as TS. m（β≥2） hour, Satisfy TS m（β<2） >TS m（β≥2） .

10. The oriented electromagnetic steel sheet according to any one of claims 1 to 5, wherein, The magnetic domain control processing line is a slot.

11. The orientation-oriented electromagnetic steel sheet according to claim 10, characterized in that, The maximum depth of the slots in the magnetic domain control processing line is not uniform at the measurement points of the depth of each slot.

12. The orientation-oriented electromagnetic steel sheet according to claim 11, characterized in that, A rectangular evaluation area with a length of 50 mm parallel to the rolling direction and a length of 100 mm parallel to the rolling right-angle direction of the oriented electromagnetic steel sheet is defined on the surface. Furthermore, within the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along a direction parallel to the rolling direction. The intersection points of the imaginary line and the multiple domain control processing lines are respectively designated as domain control points. The maximum value of the groove depth measured in μm at each of the domain control points is set as D. m The D m Let the variance be σ(D) m ) 2 hour, Satisfying σ(D) m ) 2 >3.

0.

13. The orientation-oriented electromagnetic steel sheet according to claim 11 or 12, characterized in that, The arithmetic mean of the maximum values ​​of the groove depth measured in μm at each of the domain control points with a β angle less than 2° is set as D. m（β<2） The arithmetic mean of the maximum values ​​of the groove depth measured in μm at each of the domain control points with a β angle of 2° or greater is denoted as D. m（β≥2） hour, Satisfy D m（β<2） >D m（β≥2） .

14. A method for manufacturing an orientation-oriented electromagnetic steel sheet, characterized in that, have: The process of obtaining magnetic domain images of the original oriented electromagnetic steel sheet; Based on the distribution of domain widths in the domain image, the process steps for controlling the domain processing region are determined; and The process of applying magnetic domain control processing to the magnetic domain control processing region, which is determined by the distribution of magnetic domain width; In the oriented electromagnetic steel sheet, a rectangular evaluation area is set with a side length of 50 mm parallel to the rolling direction of the oriented electromagnetic steel sheet and a side length of 100 mm parallel to the rolling right-angle direction of the oriented electromagnetic steel sheet. Furthermore, within the evaluation area, imaginary lines with a length of 100 mm parallel to the rolling right-angle direction are set at 5 mm intervals along the direction parallel to the rolling direction. In at least one of the imaginary lines, the standard deviation of the interval along the imaginary line between the intersection of the imaginary line and the magnetic domain control processing line formed by the magnetic domain control processing is set to 1.25 mm or more.

15. The method for manufacturing an orientation-oriented electromagnetic steel sheet according to claim 14, wherein, In the process of determining the domain control processing region, the region where the domain width is greater than or equal to a predetermined value is defined as the domain control processing region.

16. The method for manufacturing an orientation-oriented electromagnetic steel sheet according to claim 14 or 15, wherein, In the process of obtaining the magnetic domain image, the distribution of the magnetic domain width is derived from the magnetic domain image using a two-dimensional Fourier transform.

17. The method for manufacturing the oriented electromagnetic steel sheet according to any one of claims 14 to 16, wherein, In the process of applying the magnetic domain control process, the magnetic domain control process is applied by irradiation with a laser or electron beam.

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