Grain-oriented electrical steel sheet, and method for manufacturing grain-oriented electrical steel sheet

Abstract

This grain-oriented electromagnetic steel sheet has a magnetic domain control processing line on the surface thereof, and satisfies |α All |-|α Dr |≥ 0.1°, where |α All | is the average value of absolute values of an α angle over the entire surface of the grain-oriented electromagnetic steel sheet, and |α Dr | is the average value of absolute values of an α angle at a magnetic domain control point that is an intersection point of the magnetic domain control processing line and a plurality of virtual lines set at 2 mm intervals in parallel along a rolling direction of the grain-oriented electromagnetic steel sheet. A method for manufacturing a grain-oriented electromagnetic steel sheet according to another aspect of the present disclosure comprises: a step for measuring an α-angle distribution on the surface of an original sheet of a grain-oriented electromagnetic steel sheet; a step for identifying a region having an α-angle absolute value equal to or smaller than 5°; and a step for applying magnetic domain control processing to the region having the α-angle absolute value equal to or smaller than 5°.

Description

[Technical Field]

[0001] This invention relates to grain-oriented electrical steel sheets and methods for manufacturing grain-oriented electrical steel sheets. This invention claims priority based on Japanese Patent Application No. 2023-166173, filed in Japan on September 27, 2023, the contents of which are incorporated herein by reference. [Background technology]

[0002] Grain-oriented electrical steel sheets contain 7% by mass or less of Si, and the secondary recrystallized grains have an easy magnetization axis in the rolling direction. <001> oriented {110} <001> This is a steel sheet with a secondary recrystallized texture concentrated in a specific orientation (Goss orientation). Grain-oriented electrical steel sheets are primarily used as cores in power transformers. A reduction in energy loss (iron loss) is required for grain-oriented electrical steel sheets.

[0003] To reduce iron loss, techniques for narrowing the magnetic domain width of grain-oriented electrical steel sheets (magnetic domain subdivision technology by magnetic domain control processing) have been known for some time. The magnetic domain width can be narrowed by introducing thermal strain by irradiating the surface of the grain-oriented electrical steel sheet with a laser or electron beam in a direction intersecting the rolling direction. Alternatively, the magnetic domain width can also be narrowed by forming grooves on the surface of the grain-oriented electrical steel sheet in a direction intersecting the rolling direction. Methods for forming grooves include irradiating with a laser or electron beam, mechanical processing such as gears, and chemical processing such as etching.

[0004] In recent years, various improvement techniques related to magnetic domain subdivision have been proposed to provide grain-oriented electrical steel sheets with good iron loss characteristics (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-57219 [Patent Document 2] Japanese Patent Application Publication No. 2012-12664 [Patent Document 3] Japanese Patent Application Publication No. 2012-57218 [Overview of the project] [Problems that the invention aims to solve]

[0006] When magnetic domain control processing is applied to grain-oriented electrical steel sheets, the magnetostrictive properties of the sheet change due to the recirculating magnetic domains. This worsens the noise characteristics of the grain-oriented electrical steel sheets. Noise characteristics refer to the degree of noise generated by electrical products (e.g., transformers and motors) manufactured using grain-oriented electrical steel sheets as a material. Magnetostriction is a phenomenon in which the external shape of a ferromagnetic material is slightly deformed when it is magnetized. When grain-oriented electrical steel sheets are excited with alternating current, vibrations occur as the magnitude of the magnetostriction changes in accordance with the change in the strength of the magnetization. Although the magnitude of this magnetostriction is very small, on the order of 10⁻⁶, this magnetostriction generates vibrations in the iron core, which propagate to external structures such as transformer tanks and become noise.

[0007] In other words, while magnetic domain control processing is effective in suppressing iron loss in grain-oriented electrical steel sheets, it worsens the noise characteristics of grain-oriented electrical steel sheets. In recent years, there has been an increasing demand for not only reduced iron loss but also reduced noise in grain-oriented electrical steel sheets. However, no magnetic domain subdivision technology has been proposed that can achieve both reduced noise and reduced iron loss.

[0008] The purpose of this disclosure is to provide grain-oriented electrical steel sheets that can achieve both low iron loss and low noise, and a method for manufacturing the same. [Means for solving the problem]

[0009] The gist of this disclosure is as follows:

[0010] (1) A grain-oriented electrical steel sheet according to one aspect of the present disclosure is a grain-oriented electrical steel sheet having magnetic domain control lines on its surface, |α All |-|α Dr |≧0.1° and |αAll | is the average value of the absolute value of the α angle over the entire surface of the grain-oriented electromagnetic steel sheet, and |α Dr | is the average value of the absolute value of the α angle at the magnetic domain control points, which are the intersections of a plurality of virtual lines set at 2 mm intervals parallel to the rolling direction of the grain-oriented electromagnetic steel sheet and the magnetic domain control processing line. Furthermore, the α angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the direction normal to the rolling surface. 。 (2) Preferably, in the grain-oriented electromagnetic steel sheet according to (1) above, |α All |-|α Dr | satisfies |≧0.2°. (3) Preferably, in the grain-oriented electromagnetic steel sheet according to (1) above, |α All |-|α Dr | satisfies |≧0.5°. (4) Preferably, in the grain-oriented electromagnetic steel sheet according to (1) above, |α All |-|α Dr | satisfies |≧1.0°. (5) Preferably, in the grain-oriented electromagnetic steel sheet according to any one of (1) to (4) above, |γ All |-|α Dr | satisfies |≧0.1°, and |γ All | is the average value of the absolute value of the γ angle over the entire surface of the grain-oriented electromagnetic steel sheet. Furthermore, the γ angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the rolling direction. 。 (6) Preferably, in the grain-oriented electromagnetic steel sheet according to any one of (1) to (5) above, σα Dr <σα All is satisfied, and σα All is the standard deviation of the absolute value of the α angle over the entire surface of the grain-oriented electromagnetic steel sheet, and σα Dr is the standard deviation of the absolute value of the α angle at the magnetic domain control points. (7) Preferably, in the grain-oriented electromagnetic steel sheet according to any one of (1) to (6) above, the magnetic domain control processing line is a groove.

[0011] (8) A method for manufacturing a grain-oriented electromagnetic steel sheet according to another aspect of the present disclosure includes a step of measuring the distribution of the α angle on the surface of a base plate of the grain-oriented electromagnetic steel sheet, a step of specifying a region where the absolute value of the α angle is 5° or less, and a step of forming a magnetic domain control processing line in the region where the absolute value of the α angle is 5° or less. 、|αAll |-|α Dr |≧0.1° and |α All | is the average value of the absolute values ​​of the α angle over the entire surface of the grain-oriented electrical steel sheet, and |α Dr | is the average value of the absolute values ​​of the α angle at the magnetic domain control point, which is the intersection point of a plurality of imaginary lines set at 2 mm intervals parallel to the rolling direction of the grain-oriented electrical steel sheet and the magnetic domain control processing line, and the α angle is the deviation angle of the crystal grain from the Goss orientation around the axis in the direction normal to the rolling surface. . (9) Preferably, the method for manufacturing grain-oriented electrical steel sheets described in (8) above applies magnetic domain control processing by irradiation with a laser or electron beam. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide grain-oriented electrical steel sheets that can achieve both low iron loss and low noise, and a method for manufacturing the same. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view of a grain-oriented electrical steel sheet according to one embodiment of the present disclosure. [Figure 2] This is a plan view of a typical grain-oriented electrical steel sheet. [Figure 3] This is a schematic diagram showing an example of the configuration of a laser irradiation device. [Figure 4] This is a plan view of the raw material for grain-oriented electrical steel sheet. [Figure 5] This is an explanatory diagram of virtual lines VL1 and VL2, which are set when calculating |αAll|. [Modes for carrying out the invention]

[0014] (1. Grain-oriented electrical steel sheet 1) The grain-oriented electrical steel sheet 1 according to this embodiment has magnetic domain control processing lines 11 on its surface, |α All |-|α Dr |≧0.1° is satisfied. |α All | is the average value of the absolute values ​​of the α angle across the entire surface of the grain-oriented electrical steel sheet 1. |α Dr | represents the average value of the absolute value of the α angle at the magnetic domain control point VP2, which is the intersection point between multiple virtual lines VL3, which are set parallel to the rolling direction RD of the grain-oriented electrical steel sheet 1 at 2 mm intervals, and the magnetic domain control processing line 11.

[0015] (Magnetic domain control processing line 11) Multiple magnetic domain control processing lines 11 provided on the surface of the grain-oriented electrical steel sheet 1 have the function of subdividing the 180° magnetic domains. By subdividing the magnetic domains, the iron loss of the grain-oriented electrical steel sheet 1 can be reduced. A magnetic domain is a collection of magnetic dipoles existing inside a ferromagnetic material, and is a small region in which the magnetic moment is aligned in one direction. A 180° magnetic domain is a region in which the magnetization direction is aligned with that of the crystal. <100> A 180° magnetic domain is a magnetic domain that is situated between two 180° magnetic domain walls that are oriented and approximately parallel to the rolling direction (RD). The distance between adjacent magnetic domain walls within a 180° magnetic domain (the distance between magnetic domain walls) is referred to as the width of the 180° magnetic domain.

[0016] Preferred examples of magnetic domain control lines 11 are thermal strain and grooves. By subdividing the magnetic domains, iron loss in the grain-oriented electrical steel sheet 1 can be suppressed. However, the magnetic domain control lines 11 change the magnetostrictive properties of the grain-oriented electrical steel sheet 1 due to the recirculating magnetic domains. This worsens the noise characteristics of the grain-oriented electrical steel sheet 1.

[0017] The magnetic domain control processing lines 11 are formed in a direction intersecting the rolling direction RD of the grain-oriented electrical steel sheet 1. In a typical grain-oriented electrical steel sheet 1 as illustrated in Figure 2, the magnetic domain control processing lines 11 are formed over the entire width of the grain-oriented electrical steel sheet 1. However, in the grain-oriented electrical steel sheet 1 according to this embodiment, as illustrated in Figure 1, it is not essential to provide the magnetic domain control processing lines 11 over the entire width of the grain-oriented electrical steel sheet 1. At least some of the magnetic domain control processing lines 11 are interrupted in the region 12B where the α angle is large, as will be described later.

[0018] In the grain-oriented electrical steel sheet 1 illustrated in Figure 1, the magnetic domain control processing lines 11 are straight lines. On the other hand, the magnetic domain control processing lines 11 may be curved. The magnetic domain control processing lines 11 may have a shape that includes straight sections and bent sections. Furthermore, the magnetic domain control processing lines 11 may be present on one side or both sides of the grain-oriented electrical steel sheet 1. If the magnetic domain control processing lines 11 are present on both sides of the grain-oriented electrical steel sheet 1, it is sufficient that the various embodiments of the grain-oriented electrical steel sheet 1 according to this embodiment are applied to at least one side of the grain-oriented electrical steel sheet 1.

[0019] (α angle) In the grain-oriented electrical steel sheet 1 according to this embodiment, the value |α is calculated by measuring the α angle. All |, and |α Dr The given relationship satisfies the given equation. The α angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the direction normal to the rolling plane ND. It is known that controlling the α angle is effective in controlling the magnetic properties of the grain-oriented electrical steel sheet 1. The angle of deviation of the crystal grain from the Goss orientation around the axis in the direction perpendicular to the rolling direction TD is called the β angle, and the angle of deviation of the crystal grain from the Goss orientation around the axis in the rolling direction RD is called the γ angle.

[0020] The inventors compared the iron loss values ​​of multiple grain-oriented electrical steel sheets 1 with different α angles before and after magnetic domain control processing. As a result, it was found that when magnetic domain control processing was applied to grain-oriented electrical steel sheets with small α angles, the effect of magnetic domain control processing on reducing iron loss was greater than when it was applied to grain-oriented electrical steel sheets with large α angles. Iron loss changes before and after magnetic domain control processing, but the α angle does not. The mechanism by which the iron loss reduction effect of magnetic domain control processing is greater in the region of small α angles is not clear, but it is thought that in the region of small α angles, the deviation of the easy magnetization axis from the rolling direction is small and the hysteresis loss is small, which works favorably for reducing iron loss by magnetic domain control processing.

[0021] On the other hand, applying magnetic domain control processing to regions where the α angle is large and the effect of reducing iron loss is small is thought to lead to a deterioration of noise characteristics due to recirculating magnetic domains.

[0022] Based on the above findings, we believe that by preferentially applying magnetic domain control processing to regions with small α angles, i.e., regions where the iron loss reduction effect of magnetic domain control processing is large, both low iron loss and low noise can be achieved.

[0023] (|α All |-|α Dr |) The grain-oriented electrical steel sheet 1 according to this embodiment is |α All |-|α Dr |≧0.1° is satisfied. |αAll | is the average value of the absolute values ​​of the α angle across the entire surface of the grain-oriented electrical steel sheet 1. |α Dr | is an index of the α angle in the magnetic domain control processing line 11. Specifically, |α Dr | is the average of the absolute values ​​of the α angle at the magnetic domain control point VP2, which is the intersection point of the magnetic domain control processing line 11 with multiple virtual lines VL3 set at 2 mm intervals parallel to the rolling direction RD of the grain-oriented electrical steel sheet 1. By averaging the absolute values ​​of the α angle measured at each of the multiple magnetic domain control points VP2, |α Dr | is obtained. |α All | and |α Dr Details of the measurement method will be described later.

[0024] Grain-oriented electrical steel sheet 1 is |α All |-|α Dr When |≧0.1° is satisfied, the magnetic domain control processing lines 11 are preferentially provided in the region 12A where the α angle is small. Generally, the grain-oriented electrical steel sheet 1 has a region 12A where the α angle is small and a region 12B where the α angle is large. In the grain-oriented electrical steel sheet 1 schematically illustrated in Figure 1, the magnetic domain control processing lines 11 are preferentially placed in the region 12A where the α angle is small. Therefore, the index of the α angle in the magnetic domain control processing lines 11 is |α Dr | is the average value of the α angle across the entire surface of the grain-oriented electrical steel sheet 1 |α All It becomes smaller than |. On the other hand, in the ordinary grain-oriented electrical steel sheet 1 shown in Figure 2, the magnetic domain control processing lines 11 are arranged without considering the distribution of α angles. Therefore, the index of the α angle in the magnetic domain control processing lines 11 is |α Dr | is the average value of the α angle across the entire surface of the grain-oriented electrical steel sheet 1 |α All This is essentially the same value as |.

[0025] (Basic principles and effects) The inventors of this invention, |α All |-|α Dr We found that a grain-oriented electrical steel sheet 1 satisfying |≧0.1° can achieve both reduced iron loss and reduced noise. This is because |α All |-|α DrIn a grain-oriented electrical steel sheet 1 where |≧0.1° is satisfied, magnetic domain control processing lines 11 are provided in the region 12A where the α angle is small, i.e., the region where the magnetic domain control effect is large, while magnetic domain control processing is suppressed in the region 12B where the α angle is large, i.e., the region where the magnetic domain control effect is small.

[0026] The most basic embodiment of the grain-oriented electrical steel sheet 1 according to this embodiment has been described above. More preferred embodiments will be described below.

[0027] (|α All |-|α Dr (Preferred numerical range) |α All |-|α Dr |A larger value is preferable from the standpoint of improving noise characteristics. |α All |-|α Dr It is even more preferable that | is set to, for example, 0.2° or more, 0.5° or more, or 1.0° or more. That is, |α All |-|α Dr |≧0.2°, |α All |-|α Dr |≧0.5°, or |α All |-|α Dr It is even more preferable that the condition |≧1.0° is met. This achieves a further improvement in noise characteristics.

[0028] |α All |-|α Dr The upper limit of | is not particularly limited, but for example, |α All |-|α Dr | may be 5.0° or less, 4.0° or less, or 3.0° or less.

[0029] (|γ All |-|α Dr (Preferred numerical range) The grain-oriented electrical steel sheet 1 according to this embodiment is preferably |γ All |-|α Dr |≧0.1° is satisfied. |γ All | is the average value of the absolute values ​​of the γ angle across the entire surface of the grain-oriented electrical steel sheet 1. |γ AllThe details of the measurement method for |γ will be described later. All |-|α Dr By satisfying the condition |≧0.1°, further improvement in noise characteristics can be achieved.

[0030] (σα Dr and σα All (Relationship) The grain-oriented electrical steel sheet 1 is preferably σα Dr <σα All It satisfies σα All σα is the standard deviation of the absolute value of the α angle over the entire surface of the grain-oriented electrical steel sheet 1. Dr σα is the standard deviation of the absolute value of the α angle at the magnetic domain control point VP2, which is the intersection point of the magnetic domain control processing line 11 with multiple virtual lines VL3 set at 2 mm intervals parallel to the rolling direction RD of the grain-oriented electrical steel sheet 1. Dr <σα All In a grain-oriented electrical steel sheet 1 that satisfies the above conditions, the variation in the α angle at the magnetic domain control point VP2 is smaller than the overall variation in the α angle of the grain-oriented electrical steel sheet 1. In other words, in this case, since the magnetic domain control treatment is concentrated in the region where the iron loss reduction effect is large, a further improvement in noise characteristics is achieved.

[0031] (Configuration of magnetic domain control processing line 11) 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 using means such as laser irradiation, electron beam irradiation, and ion implantation. Grooves can be formed using means such as laser irradiation, electron beam irradiation, and machining.

[0032] Thermal distortion is eliminated by distortion-relieving annealing or a similar heat treatment. Therefore, when the grain-oriented electrical steel sheet 1 is heat-treated, it is preferable to make the magnetic domain control treatment lines 11 grooves. On the other hand, since thermal distortion can be easily formed, it is preferable to make the magnetic domain control treatment lines 11 thermal distortion when simplification of the manufacturing process is required. The grain-oriented electrical steel sheet 1 may have both thermal distortion and grooves.

[0033] (2. Manufacturing equipment for grain-oriented electrical steel sheet 1) Next, an example of a manufacturing apparatus for the grain-oriented electrical steel sheet 1 according to this embodiment will be described. However, the manufacturing apparatus described below is merely illustrative. The grain-oriented electrical steel sheet 1 according to this embodiment can be manufactured using any apparatus.

[0034] Known methods such as laser irradiation, electron beam irradiation, and ion implantation can be used to introduce thermal strain to the surface of the original plate 2. Known methods such as laser irradiation, electron beam irradiation, and machining can be used to form grooves on the surface of the original plate 2. The configuration of the laser irradiation device 500 that introduces thermal strain by laser irradiation will be described below.

[0035] Figure 3 shows the configuration of the laser irradiation device 500. The laser irradiation device 500 comprises a polygon mirror 501, a light source device 503, a collimator 505, a focusing lens 507, a motor 509, a sensor 511, a control unit 513, and a plate feeding device 515.

[0036] The sheet feeding device 515 feeds the raw sheet 2 in the rolling direction RD.

[0037] The polygon mirror 501 is, for example, shaped like a regular polygonal prism. Multiple plane mirrors are provided on each of the multiple sides that make up the regular polygonal prism-shaped polygon mirror 501. The laser beam LB is incident on the plane mirrors of the polygon mirror 501 in one direction (horizontally) from the light source device 503 via the collimator 505 and is reflected by the plane mirrors.

[0038] The polygon mirror 501 is rotatable around the rotation axis O1 by drive from the motor 509. The incident angle of the laser beam LB on the plane mirror changes sequentially according to the rotation angle of the polygon mirror 501. This sequentially changes the reflection direction of the laser beam LB, allowing the surface of the original plate 2 to be scanned. In Figure 3, the symbol P represents the spacing between adjacent magnetic domain control processing lines 11, i.e., the irradiation pitch of the laser beam LB.

[0039] The light source device 503 outputs a laser beam LB in a predetermined irradiation method (for example, a continuous irradiation method or a pulsed irradiation method) under the control of the control unit 513.

[0040] The focusing lens 507 is positioned in the optical path of the laser beam LB reflected from the polygon mirror 501. The focusing lens 507 constitutes a focusing optical system with a predetermined focal length. The laser beam LB reflected from the polygon mirror 501 is focused onto the surface of the original plate 2 via the focusing lens 507, thereby introducing thermal strain to the surface of the original plate 2.

[0041] Motor 509 is connected to the polygon mirror 501. Under the control of the control unit 513, motor 509 rotates the polygon mirror 501.

[0042] Sensor 511 is connected to the drive shaft of motor 509. Sensor 511 detects the rotation angle of the polygon mirror 501, which is rotated by motor 509. Furthermore, sensor 511 outputs a signal indicating the detected rotation angle (hereinafter referred to as the rotation angle signal) to control unit 513.

[0043] The control unit 513 consists of a processor. The control unit 513 is connected to the light source device 503, the motor 509, the sensor 511, and the sheet feed device 515. The control unit 513 receives a speed signal input from the sheet feed device 515. Furthermore, the control unit 513 outputs a signal to the motor 509 instructing it to rotate the polygon mirror 501.

[0044] Furthermore, the control unit 513 controls the on / off state of the laser beam LB output by the light source device 503 based on the stress introduction signal representing the magnetic domain control processing area 21 and the rotation angle signal output from the sensor 511. The stress introduction signal is input to the laser irradiation device 500 based on position data obtained in the process of identifying the region where the absolute value of the α angle is 5° or less, which will be described later.

[0045] (3. Method for manufacturing grain-oriented electrical steel sheet 1) Next, a method for manufacturing the grain-oriented electrical steel sheet 1 according to this embodiment will be described. According to the method for manufacturing the grain-oriented electrical steel sheet 1 according to this embodiment, the grain-oriented electrical steel sheet 1 can be suitably manufactured. However, the manufacturing method described below is merely one example of a suitable manufacturing method for the grain-oriented electrical steel sheet 1 and does not limit the grain-oriented electrical steel sheet 1. For convenience of explanation, manufacturing equipment will be appropriately referred to in the description of the manufacturing method. However, the manufacturing equipment referred to below is merely a preferred example for carrying out the manufacturing method for the grain-oriented electrical steel sheet 1 according to this embodiment.

[0046] The manufacturing method for the grain-oriented electrical steel sheet 1 according to this embodiment comprises the steps of: measuring the α angle; identifying a region in which the absolute value of the α angle is 5° or less; and applying magnetic domain control processing to the region in which the absolute value of the α angle is 5° or less.

[0047] (Process for measuring the distribution of alpha angles) First, the distribution of α angles on the surface of the raw material of grain-oriented electrical steel sheet 1 is measured. The α angle is measured using the side reflection Laue method described later.

[0048] The original sheet 2 refers to the grain-oriented electrical steel sheet 1 before the magnetic domain control processing is applied.

[0049] (A process to identify the region where the absolute value of the α angle is 5° or less) Next, based on the distribution of α angles, a region on the surface of the original plate where the absolute value of the α angle is 5° or less is identified. Hereinafter, the region where the absolute value of the α angle is 5° or less will be referred to as the magnetic domain control processing region 21.

[0050] (Process for forming magnetic domain control lines) Figure 4 shows a plan view of an example of a base plate 2. Figure 4 shows the magnetic domain control processing region 21 and the non-magnetic domain control processing region 22 of the base plate 2. Magnetic domain control processing is applied to the dashed lines shown in Figure 4. Magnetic domain control processing lines can be formed using known magnetic domain control processing means. If the magnetic domain control processing line 11 is thermal strain, magnetic domain control processing may be performed by irradiation with a laser beam LB from a laser irradiation device 500, or other means such as ion implantation or electron beam irradiation may be employed. If the magnetic domain control processing line 11 is a groove, magnetic domain control processing may be performed using a tool for machining.

[0051] The control unit 513 of the laser irradiation device 500 controls the power of the laser beam LB to be turned on for the magnetic domain control processing area 21, and preferably to be turned off for the non-magnetic domain control processing area 22 (i.e., areas other than the magnetic domain control processing area 21). As a result, magnetic domain control processing lines 11 are introduced into the magnetic domain control processing area 21 of the original plate 2. In addition, the introduction of magnetic domain control processing lines 11 in the non-magnetic domain control processing area 22 of the original plate 2 is minimized.

[0052] (Effects and Benefits) According to the manufacturing method described above, it is possible to produce steel plates that achieve both low iron loss and low noise.

[0053] Although embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention. Further preferred examples of the grain-oriented electrical steel sheet 1 and its manufacturing method according to this embodiment are described below. Unless otherwise specified, the preferred embodiments described below are applicable to both the grain-oriented electrical steel sheet 1 and its manufacturing method. The grain-oriented electrical steel sheet according to this embodiment may have a forsterite coating and / or an insulating coating on the surface of the base steel sheet, as will be described later. The following will explain each of these points. However, if the grain-oriented electrical steel sheet has a base steel sheet and a forsterite coating and / or insulating coating, the following provisions regarding chemical composition, magnetic domain control lines, magnetic domain control regions, and non-magnetic domain control lines apply to the base steel sheet. However, the provisions regarding sheet thickness apply to the entire grain-oriented electrical steel sheet, including the base steel sheet and the forsterite coating and / or insulating coating.

[0054] (Chemical composition and plate thickness) The chemical composition of grain-oriented electrical steel sheet 1 and base sheet 2 is not limited and may be equivalent to that of known grain-oriented electrical steel sheet 1. For example, the chemical composition of grain-oriented electrical steel sheet 1 and base sheet 2 is as follows (in mass%): 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: 0~0.300%, S The chemical composition may be as follows: b: 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 remainder of the chemical composition includes Fe and impurities.

[0055] The thickness of the grain-oriented electrical steel sheet 1 and the base sheet 2 is not limited, but is preferably, for example, 0.15 to 0.30 mm. By setting the thickness to 0.30 mm or less, classical eddy current losses can be suppressed and iron loss can be further improved. On the other hand, by setting the thickness to 0.15 mm or more, rolling efficiency can be improved and productivity can be improved.

[0056] (Surface treatment) The grain-oriented electrical steel sheet 1 and the base sheet 2 may have a forsterite coating. Furthermore, the grain-oriented electrical steel sheet 1 and the base sheet 2 may have an insulating coating. The forsterite coating and the insulating coating may be formed on one side or both sides of the grain-oriented electrical steel sheet 1.

[0057] Forsterite coatings are inorganic coatings, for example, those primarily composed of magnesium silicate. Forsterite coatings are formed, for example, during finish annealing, by a reaction between an annealing separation agent containing magnesia (MgO) applied to the surface of the base steel sheet and the components of the base steel sheet surface. Forsterite coatings have a composition derived from, for example, the annealing separation agent and the components of the base steel sheet (more specifically, a composition primarily composed of Mg2SiO4). On the other hand, if an annealing separation agent mainly composed of Al2O3 is used in finish annealing, forsterite coatings may not be formed.

[0058] The insulating coating has the function of imparting electrical insulation and tension to the grain-oriented electrical steel sheet 1. By imparting tension to the grain-oriented electrical steel sheet 1 and facilitating magnetic domain wall movement in the grain-oriented electrical steel sheet 1, iron loss in the grain-oriented electrical steel sheet 1 can be reduced. Furthermore, the insulating coating can impart various properties such as corrosion resistance, heat resistance, and slipperiness to the grain-oriented electrical steel sheet 1. The insulating coating may be a known coating formed, for example, by applying a coating solution mainly composed of phosphate and colloidal silica to the surface of a forsterite coating and baking it.

[0059] It is preferable to form the insulating coating after finish annealing and after magnetic domain control treatment. On the other hand, the insulating coating may be formed after the finish annealing process and before the magnetic domain control treatment. If the insulating coating is formed before the magnetic domain control treatment, the insulating coating may peel off on the magnetic domain control treatment wire 11. Therefore, it is preferable to re-form the insulating coating on the magnetic domain control treatment wire 11 after the magnetic domain control treatment.

[0060] (Angle between the magnetic domain control processing line 11 and the rolling direction perpendicular to it TD) The angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD is not particularly limited. The magnetic domain control processing line 11 and the rolling perpendicular direction TD may be approximately parallel. That is, the angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD may be substantially 0°. On the other hand, as illustrated in Figure 1, the angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD may be greater than 0°. For example, the angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD may be any value within the range of 0° to 45°. The angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD may be 1° or more, 3° or more, or 5° or more. The angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD may be 40° or less, 35° or less, or 30° or less.

[0061] As illustrated in Figure 1, the angle between all magnetic domain control lines 11 and the rolling perpendicular direction TD may be the same. That is, all magnetic domain control lines 11 may extend parallel to each other. On the other hand, the angles between the magnetic domain control lines 11 and the rolling perpendicular direction TD may vary. That is, some or all of the multiple magnetic domain control lines 11 may extend non-parallel to each other. The average value of the angle between the magnetic domain control lines 11 and the rolling perpendicular direction TD may be 1° or more, 3° or more, or 5° or more. The average value of the angle between the magnetic domain control lines 11 and the rolling perpendicular direction TD may be 40° or less, 35° or less, or 30° or less. The average value of the angle can be calculated by measuring the angle between a single magnetic domain control line and the rolling perpendicular direction TD at multiple positions, or by measuring the angle between multiple magnetic domain control lines and the rolling perpendicular direction TD at one or more positions and calculating the average value.

[0062] (Spacing of magnetic domain control processing lines 11 along the rolling direction RD) The spacing P between adjacent magnetic domain control processing lines 11 along the rolling direction RD is not particularly limited. A smaller spacing P enhances the effect of improving iron loss. On the other hand, a larger spacing P improves noise characteristics. The spacing can be appropriately selected according to the characteristics required for the grain-oriented electrical steel sheet 1. For example, the spacing P between adjacent magnetic domain control processing lines 11 along the rolling direction RD may be 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, or 5.0 mm or more. The spacing P between adjacent magnetic domain control processing lines 11 along the rolling direction RD may be 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, or 7.0 mm or less.

[0063] In the grain-oriented electrical steel sheet 1 illustrated in Figure 1, magnetic domain control processing lines 11 are provided at regular intervals. On the other hand, the spacing P along the rolling direction RD of adjacent magnetic domain control processing lines 11 along the rolling direction RD may vary. For example, the average value of the spacing P along the rolling direction RD of adjacent magnetic domain control processing lines 11 along the rolling direction RD may be 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 spacing P along the rolling direction RD of adjacent magnetic domain control processing lines 11 along the rolling direction RD may be 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, or 7.0 mm or less.

[0064] (The magnitude of tensile stress introduced in thermal strain) The magnetic domain control processing line 11 may also be thermal strain. In the case of thermal strain, tensile stress is introduced. The greater the tensile stress, the greater 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 according to the characteristics required for the grain-oriented electrical steel sheet 1.

[0065] The magnitude of the tensile stress is not particularly limited, but it is preferable that, for example, in at least a portion of the magnetic domain control processing line 11, the tensile stress in any direction is 40 MPa or more, 60 MPa or more, or 80 MPa or more. If the tensile stress in at least one direction is 40 MPa or more, the requirement that "the tensile stress in any direction is 40 MPa or more" is considered to be met. Also, for example, it is preferable that, in at least a portion of the magnetic domain control processing line 11, the tensile stress in any direction is 300 MPa or less, 200 MPa or less, 180 MPa or less, or 150 MPa or less. The tensile stress in any direction in the magnetic domain control processing line 11 may be uniform or may vary.

[0066] (Depth and width of the groove) The magnetic domain control processing lines 11 may be grooves. The greater the depth and width of the grooves, the greater the effect of improving iron loss. On the other hand, the smaller the depth and width of the grooves, the better the noise characteristics. The shape of the grooves can be appropriately selected according to the characteristics required for the grain-oriented electrical steel sheet 1.

[0067] The groove depth is not particularly limited, but is preferably, for example, 5 μm to 50 μm. The groove depth may be 6 μm or more, 7 μm or more, or 10 μm or more. The groove depth may be 48 μm or less, 45 μm or less, or 40 μm or less.

[0068] The groove width (width at the opening) is not particularly limited, but is preferably, for example, 10 μm to 300 μm. The groove width may also be specified as 20 μm or more, 30 μm or more, or 50 μm or more. The groove width may also be specified as 280 μm or less, 250 μm or less, or 200 μm or less. The groove depth and width may be uniform or vary. If they vary, it is preferable that the average of the depth and width of multiple grooves is within the above range.

[0069] (Number of magnetic domain control points) The more magnetic domain control points there are, the more magnetic domain control lines there are, and the wider the area that is magnetic domain controlled. Therefore, from the viewpoint of reducing iron loss, a large number of magnetic domain control points is preferable. For example, if the number of magnetic domain control points in grain-oriented electrical steel sheet 1 is 10,000 mm 2 It is preferable that the score is 10 points or more, 50 points or more, or 100 points or more per person.

[0070] (Measurement method) The following describes methods for measuring various parameters of the grain-oriented electrical steel sheet 1 according to this embodiment. All parameter measurements are performed on a sample taken from the grain-oriented electrical steel sheet 1. For example, a rectangular sample with sides measuring 100 mm (or 100 mm or more) can be cut from the grain-oriented electrical steel sheet 1 and used for measurement. If the grain-oriented electrical steel sheet 1 is a coil, a sample can be taken from any point on the coil. Similarly, if the grain-oriented electrical steel sheet 1 is a component incorporated into electrical products such as transformers or motors, a sample can be taken from any point on the component. If the component is small, the length of one side of the sample may be less than 100 mm. In this case, the total sample area should be 10,000 mm². 2 The above should be achieved. In this process, it is desirable to collect the sample using methods such as wire cutting to minimize the effects of mechanical distortion on the sample.

[0071] (Method for identifying magnetic domain control processing lines 11) If the magnetic domain control processing line 11 is a groove, the magnetic domain control processing line 11 can be identified visually. If the grain-oriented electrical steel sheet 1 has an insulating coating, the magnetic domain control processing line 11 can be identified visually by removing the insulating coating using a known stripping agent.

[0072] If the magnetic domain control processing line 11 is due to thermal strain, the magnetic domain control processing line 11 may not be visible. In this case, for example, an image acquisition device is used to capture a magnetic domain image. If necessary, a DC magnetic field is applied along the direction ND, which is the normal direction to the rolling surface of the grain-oriented electrical steel sheet 1, while capturing the magnetic domain image. By observing the magnetic domain image, the location of the thermal strain can be identified.

[0073] (Method for determining the rolling direction RD and the direction perpendicular to the rolling direction TD) The rolling direction RD and the direction perpendicular to the rolling direction TD of the grain-oriented electrical steel sheet 1 are determined by the following means. (1) If the sample is cut from a coiled grain-oriented electrical steel sheet 1, the width direction of the coil is considered to be the rolling direction TD. Also, the direction perpendicular to the rolling direction TD and the rolling surface normal direction ND is considered to be the rolling direction RD. (2) If the sample is cut from a component of an electrical product, the rolling direction RD and the direction perpendicular to the rolling direction TD are determined from the rolling defects on the surface of the grain-oriented electrical steel sheet 1. The direction in which the rolling defects extend is considered to be the rolling direction RD. The direction perpendicular to the rolling direction RD and the direction normal to the rolling surface ND is considered to be the direction perpendicular to the rolling direction TD. (3) If it is difficult to determine the rolling direction RD and the direction perpendicular to rolling TD from the rolling defects on the surface of the grain-oriented electrical steel sheet 1, the rolling direction RD and the direction perpendicular to rolling TD shall be determined from the crystal orientation of the grain-oriented electrical steel sheet 1. Specifically, the crystal orientation of the grain-oriented electrical steel sheet 1 to be evaluated shall be measured at multiple points. The easy magnetization axis whose angle with respect to the crystal orientation at the measurement point is closest to a right angle with respect to the rolling surface normal direction ND (thickness direction) shall be determined. <001> The direction in which the deviation angle from the rolling plane is minimized is considered the rolling direction RD, and the direction perpendicular to the rolling direction RD and the direction normal to the rolling plane ND is considered the direction perpendicular to the rolling plane TD.

[0074] (Method for measuring α-angle and γ-angle) The α and γ angles are measured by the side reflection Laue method. The side reflection Laue method is a widely known method for measuring crystal orientation. However, the α and γ angles are obtained by rounding the measured values ​​to the second decimal place. That is, the significant figures of the α and γ angles are limited to the first decimal place.

[0075] (Method for measuring the distribution of alpha angles) The method for measuring the distribution of α angles on the surface of the raw material of grain-oriented electrical steel sheet 1 is as follows: Measurement points are set in a grid pattern on the surface of the raw material of grain-oriented electrical steel sheet 1. The α angle is measured at each measurement point.

[0076] Specifically, on the surface of the raw grain electrical steel sheet 1, measurement points are set in a grid pattern at 2 mm intervals along the rolling direction RD and the direction perpendicular to rolling TD. The α angle is measured at each measurement point, and the distribution of the α angle on the surface of the raw grain electrical steel sheet 1 is measured.

[0077] (|α All (Calculation method) |α All The general method for calculating | is as follows: On the surface of a sample taken from grain-oriented electrical steel sheet 1, measurement points are set in a grid pattern as illustrated in Figure 5. At each measurement point, the absolute value of the α angle is measured, and the average value of these is calculated. This average value is |α All |To be considered as.

[0078] Specifically, for a sample with sides of 100 mm or more (the rectangular area enclosed by the dashed line in Figure 5), a virtual line VL1 parallel to the rolling direction TD and a virtual line VL2 parallel to the rolling direction RD are set on the surface. The existence of the magnetic domain control processing line 11 is not considered when setting virtual lines VL1 and VL2. The spacing of virtual lines VL1 and VL2 is set to 2 mm. Virtual lines VL1 and VL2 are placed across the entire surface of the sample. The absolute value of the α angle at the intersection point VP1 of virtual lines VL1 and VL2 is measured.

[0079] (|α Dr (Calculation method) |α Dr The method for calculating | is as follows. First, on the surface of a sample with sides of 100 mm or more (the rectangular area enclosed by the dashed line in Figure 1 or Figure 2), multiple imaginary lines VL3 are set at regular intervals parallel to the rolling direction RD of the grain-oriented electrical steel sheet 1. VL3 is |α All The virtual line VL2 parallel to the rolling direction RD during the calculation of | may be the same as or different from the virtual line VL3. The spacing of the virtual lines VL3 is 2 mm. The virtual lines VL3 are placed across the entire surface of the sample. Next, the magnetic domain control point VP2 (i.e., the intersection of the virtual line VL3 and the magnetic domain control processing line 11) is identified. Then, the absolute value of the α angle at each magnetic domain control point VP2 is measured and their average value is calculated. This average value is |αDr is regarded as. The method for specifying the rolling direction RD and the magnetic domain control processing line 11, and the method for measuring the α angle are as described above.

[0080] (Measurement method of σα All ) σα All is obtained by calculating the standard deviation of the absolute value of the α angle at each measurement point used for the calculation of |α All . The method for specifying the absolute value of the α angle at each measurement point is as described above.

[0081] (Measurement method of σα Dr ) σα Dr is obtained by calculating the standard deviation of the absolute value of the α angle at each magnetic domain control point VP2. The method for specifying the magnetic domain control point VP2 is as described above.

[0082] (Calculation method of |γ All ) |γ All The outline of the calculation method of |γ is as follows. For the surface of the sample taken from the directionally electromagnetic steel sheet 1, as illustrated in FIG. 5, measurement points are set in a grid pattern at intervals of 2 mm along the rolling direction RD and the direction perpendicular to rolling TD. At each measurement point, the absolute value of the γ angle is measured, and the average value of these is calculated. This average value is regarded as |γ All .

[0083] (Measurement method of the chemical components of the base plate 2 and the directionally electromagnetic steel sheet 1) The chemical composition of grain-oriented electrical steel sheet 1 and base sheet 2 can be measured using general analytical methods for steel. For example, the chemical composition can be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Specifically, a test piece is taken from the center of the sample in the thickness direction, and the chemical composition of grain-oriented electrical steel sheet 1 and base sheet 2 can be measured using a Shimadzu ICPS-8100 or similar (measuring device) under conditions based on a pre-prepared calibration curve. The C and S content, which is difficult to measure with ICP-AES, can be measured using the combustion-infrared absorption method. The N content can be measured using the inert gas fusion-thermal conductivity method.

[0084] If a forsterite coating and / or insulating coating is formed on the grain-oriented electrical steel sheet 1, the forsterite coating and / or insulating coating should be removed from the grain-oriented electrical steel sheet 1 before analyzing the chemical composition of the grain-oriented electrical steel sheet 1 (i.e., the chemical composition of the base steel sheet). The insulating coating 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 adjusted appropriately so that the base metal of the sample does not dissolve excessively. An example of the conditions for removing the insulating coating is as follows: First, immerse the sample in a 20% sodium hydroxide solution at 80°C for 15 minutes. Then, dry the sample. Next, immerse the sample in a 10% dilute sulfuric acid solution at 80°C for 4 minutes. After that, remove any sludge adhering to the surface of the sample with a cloth or the like. Furthermore, immerse the sample in a 10% nitric acid solution at room temperature for about 10 seconds while stirring. Forsterite coatings can be removed, for example, by immersing the sample in sulfuric acid followed by immersion in nitric acid. The temperature, concentration, and immersion time of the sulfuric acid and nitric acid should be adjusted as appropriate to prevent excessive dissolution of the sample's base metal. 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 cloth or similar to remove any sludge adhering to the surface. After that, dry the sample. Furthermore, immerse the sample in 10% nitric acid at room temperature for about 5 seconds while stirring.

[0085] (Method for measuring the angle between the magnetic domain control processing line 11 and the rolling direction perpendicular to it (TD)) The angle between the magnetic domain control processing line 11 and the rolling perpendicular direction TD can be measured using known angle measuring means after identifying the magnetic domain control processing line 11 and the rolling perpendicular direction TD using the procedure described above.

[0086] (Method for measuring the spacing of magnetic domain control processing lines 11 along the rolling direction RD) The spacing of the magnetic domain control processing lines 11 along the rolling direction RD can be measured using known length measuring means after identifying the magnetic domain control processing lines 11 and the rolling direction RD using the procedure described above.

[0087] (A method for measuring the magnitude of tensile stress, introduced in thermal strain measurements.) The magnitude of the tensile stress introduced during thermal strain is measured 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.

[0088] When measuring the magnitude of tensile stress introduced by thermal strain using the EBSD Wilkinson method and BLG Vantage's Cross Court, first, the magnetic domain control processing lines 11 are identified using the procedure described above. Next, the grain-oriented electrical steel sheet 1 is cut through the magnetic domain control processing lines 11 and perpendicular to them. This cut surface is used as the measurement surface. The cross section of the magnetic domain control processing lines 11 included in the measurement surface is analyzed using the EBSD Wilkinson method and BLG Vantage's Cross Court to extract tensile stress components in any direction and measure their magnitude. For example, tensile stress components can be extracted in the direction normal to the rolling surface ND, in the direction parallel to the magnetic domain control processing lines 11, and in the direction perpendicular to both the rolling surface normal to the rolling surface ND and the magnetic domain control processing lines 11.

[0089] The number of measurement points is, for example, 10. If the tensile stress in any direction is 40 MPa or more at at least one location on the grain-oriented electrical steel sheet 1 (i.e., the tensile stress in at least one direction is 40 MPa or more), then it is determined that the maximum value of the tensile stress in any direction in the magnetic domain control processing lines of the grain-oriented electrical steel sheet 1 is 40 MPa or more. The measurement of tensile stress may be stopped when a measurement point is found where the tensile stress in any direction is 40 MPa or more.

[0090] (Method for measuring groove depth and width) The depth and width of the grooves can be measured by determining the surface shape of the sample using a known three-dimensional measuring machine. If the grain-oriented electrical steel sheet 1 has a tension insulating coating, the insulating coating is removed using the procedure described above before performing three-dimensional measurement of the sample surface. [Examples]

[0091] The effects of one aspect of the present invention will be further explained in detail by the examples. However, the conditions in the examples are merely examples of conditions adopted to confirm the feasibility and effects of the present invention. The present invention is not limited to these examples of conditions. The present invention can adopt various conditions as long as it does not depart from the spirit of the invention and achieves the objectives of the present invention.

[0092] A non-oriented electrical steel sheet of the same lot with a thickness of 0.20 mm was used as the original sheet. The original sheet was subjected to domain control treatment under various conditions shown in Table 1. The noise and iron loss of the domain control-treated non-oriented electrical steel sheet thus obtained were evaluated and described in Table 2. In Table 1, values outside the range of the non-oriented electrical steel sheet according to the present embodiment are underlined. In Table 2, values that do not satisfy the following pass / fail criteria are underlined.

[0093] The evaluation methods for noise and iron loss were as follows. First, 205 non-oriented electrical steel sheets with a thickness of 0.20 mm were laminated to fabricate a three-phase transformer core. Both the legs and the width of the yoke of the three-phase transformer core were 150 mm. Both the height and the width of the outer shape of the three-phase transformer core were 750 mm. The noise and iron loss of these three-phase transformer cores were measured. The measurement conditions were a frequency of 60 Hz and an excitation magnetic flux density of 1.8 T.

[0094] In measuring the noise, microphones were arranged at equal intervals at eight locations around the transformer in which the three-phase transformer core was incorporated. The distance between the transformer and the microphones was 30 cm. The values obtained by subjecting the noise measurement results by these microphones to A characteristic correction and averaging were described in Table 2 as the noise evaluation results (unit: dBA) of the non-oriented electrical steel sheet. An example in which the noise evaluation result was 51.00 dBA or less was determined to be an example in which low noise was achieved. The noise evaluation results determined to be不合格 were underlined.

[0095] The iron loss was determined by measuring the voltages and currents on the primary and secondary sides with a power analyzer when excitation was performed at a frequency of 60 Hz and an excitation magnetic flux density of 1.8 T as described above. The obtained iron loss was described in Table 2 as the iron loss evaluation result (unit: W / kg) of the non-oriented electrical steel sheet. An example in which the iron loss evaluation result was 1.270 W / kg or less was determined to be an example in which low iron loss was achieved. The noise evaluation results determined to be不合格 were underlined.

[0096] Furthermore, in the domain control-treated non-oriented electrical steel sheet, |α All |, |α Dr |, |γ All|, σα All And, σα Dr The measurements were taken and recorded in Table 2. The measurement method followed the procedure described above in principle. Rectangular samples with sides of 100 mm were cut from the core of a three-phase transformer used for noise and iron loss measurements and used for the measurements.

[0097] [Table 1]

[0098] [Table 2]

[0099] In example number 10, all magnetic domain control lines were formed across the entire width of the grain-oriented electrical steel sheet. As a result, in example number 10, |α All |-|α Dr The temperature did not meet the requirement of |≧0.1°. In example number 10, the iron loss was within the acceptable range, but the noise characteristics were unacceptable.

[0100] In example number 11, the magnetic domain control processing lines were formed in a dashed line shape. In other words, in example number 11, as in examples 1 to 9, a region was provided where magnetic domain control processing was not performed. However, in example number 11, the size of the gaps between the magnetic domain control processing lines included in the dashed line was randomly varied. The areas where magnetic domain control processing was not performed were randomly provided. As a result, in example number 11, |α All |-|α Dr The condition |≧0.1° was not met. In example number 11, the iron loss was within the acceptable range, but it was the same value as the passing value of 1.270. Also in example number 11, the noise characteristics were unacceptable.

[0101] In example number 12, the magnetic domain control processing lines were formed in a regular dashed pattern. In other words, as with examples 1 to 9, example number 12 included regions where magnetic domain control processing was not performed. However, in example number 12, the size of the gaps between the magnetic domain control processing lines included in the dashed lines was set to a constant value. The areas where magnetic domain control processing was not performed were regularly spaced. As a result, in example number 12, |αAll |-|α Dr The condition |≧0.1° was not met. In example number 12, both iron loss and noise characteristics were unsatisfactory.

[0102] In examples 13 and 14, as in example 11, the magnetic domain control processing lines were formed as dashed lines. In other words, examples 13 and 14, like examples 1 to 9, included regions where magnetic domain control processing was not performed. However, in examples 13 and 14, magnetic domain control processing was applied to regions where the α angle was greater than a predetermined value, limited based on the distribution of the α angle. These examples also include |α All |-|α Dr The condition |≧0.1° was not met. In examples 13 and 14, the iron loss was unacceptable.

[0103] On the other hand, in examples 1 to 9, magnetic domain control processing was applied to a region where the α angle is less than or equal to a predetermined value, which was limited based on the distribution of the α angle. Examples 1 to 9 are |α All |-|α Dr The |≧0.1° condition was met, and both noise characteristics and iron loss were within acceptable limits. Examples 1-9 demonstrated that both reduced iron loss and reduced noise levels were achieved.

[0104] According to examples 1-9, |α All |-|α Dr It was confirmed that the larger the | value, the better the noise characteristics. Also, in examples 6-9, |γ All |-|α Dr The condition |≧0.1° was met. In these examples, the noise characteristics were even better. Also, in example number 9, |γ All |-|α Dr |≧0.1° is satisfied, and σα Dr <σα All The conditions were met. In this example, the noise characteristics were even better. [Industrial applicability]

[0105] The hot-rolled steel sheet of this disclosure can achieve both low iron loss and low noise, and therefore has high potential for industrial use. [Explanation of Symbols]

[0106] 1 Grain-oriented electrical steel sheet 11 Magnetic Domain Control Processing Line 12A Region with small α angle 12B Region with large α angle RD (Rolling Direction) TD (Rolling direction perpendicular to the rolling direction) ND (Direction normal to the rolling surface) VL1 | α All |A virtual line parallel to TD for calculation purposes VL2 | α All |A virtual line parallel to RD for calculation purposes VL3 | α Dr |A virtual line parallel to TD for calculation purposes VP1 Intersection of virtual line VL1 and virtual line VL2 VP2 Magnetic Domain Control Point 2 Original plate 21 Magnetic Domain Control Processing Area 22 Non-magnetic domain control processing area 30 Image acquisition device 31 Light source section 500 Laser Irradiation Devices 501 Polygon Mirror 503 Light source device 505 Collimator 507 Focusing lens 509 Motor 511 Sensor 513 Control Unit 515 Threading equipment

Claims

1. A grain-oriented electrical steel sheet having magnetic domain control lines on its surface, | α Ａｌｌ |-|α Ｄｒ Satisfying the condition |≧0.1°, | α Ａｌｌ | is the average value of the absolute values ​​of the α angle over the entire surface of the aforementioned grain-oriented electrical steel sheet. | α Ｄｒ | represents the average value of the absolute value of the α angle at the magnetic domain control point, which is the intersection point between the multiple virtual lines set parallel to the rolling direction of the grain-oriented electrical steel sheet at 2 mm intervals and the magnetic domain control processing line. The aforementioned α angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the direction normal to the rolling surface. Grain-oriented electrical steel sheet.

2. | α Ａｌｌ |-|α Ｄｒ The grain-oriented electrical steel sheet according to claim 1, satisfying |≧0.2°.

3. | α Ａｌｌ |-|α Ｄｒ A grain-oriented electrical steel sheet according to claim 1, satisfying |≧0.5°.

4. |α Ａｌｌ | - |α Ｄｒ The grain-oriented electromagnetic steel sheet according to claim 1, satisfying |≧1.0°.

5. |γ Ａｌｌ |-|α Ｄｒ Satisfying the condition |≧0.1°, |γ Ａｌｌ | represents the average value of the absolute values ​​of the γ angle across the entire surface of the grain-oriented electrical steel sheet. The aforementioned γ angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the rolling direction. A grain-oriented electrical steel sheet according to any one of claims 1 to 4.

6. σα Ｄｒ <σα Ａｌｌ Satisfying the conditions, σα Ａｌｌ This is the standard deviation of the absolute value of the α angle over the entire surface of the grain-oriented electrical steel sheet, σα Ｄｒ This is the standard deviation of the absolute value of the α angle at the magnetic domain control point. A grain-oriented electrical steel sheet according to any one of claims 1 to 4.

7. The grain-oriented electrical steel sheet according to any one of claims 1 to 4, wherein the magnetic domain control processing line is a groove.

8. A process for measuring the distribution of α angles on the surface of a grain-oriented electrical steel sheet, A step of identifying a region where the absolute value of the α angle is 5° or less, The process of forming magnetic domain control lines in the region where the absolute value of the α angle is 5° or less, Equipped with, |α All |-|α Dr | ≥ 0.1° satisfies, |α All| is the average value of the absolute values ​​of the α angle over the entire surface of the grain-oriented electrical steel sheet. |α Dr| is the average value of the absolute value of the α angle at the magnetic domain control point, which is the intersection point of a plurality of virtual lines set at 2 mm intervals parallel to the rolling direction of the grain-oriented electrical steel sheet and the magnetic domain control processing line. The aforementioned α angle is the angle of deviation of the crystal grain from the Goss orientation around the axis in the direction normal to the rolling surface. A method for manufacturing grain-oriented electrical steel sheets.

9. A method for manufacturing grain-oriented electrical steel sheets according to claim 8, characterized in that magnetic domain control processing is applied by irradiation with a laser or electron beam.

Images