Grain-oriented electrical steel sheet and method for producing same

Abstract

This grain-oriented electrical steel sheet is provided with a base material steel sheet having a plurality of grooves extending in a direction intersecting the rolling direction, a forsterite coating film optionally formed on the base material steel sheet, and an insulating coating film formed on the base material steel sheet or on the forsterite coating film, and is characterized in that the direction in which the grooves extend is defined as the longitudinal direction of the grooves, and that the direction in which the grooves extend is defined as the longitudinal direction of the grooves. The distance from an imaginary line extending from the surface of the base steel sheet to the groove is defined as the depth of the groove, the width of the groove in the rolling direction is defined as the width of the groove, the position where the depth of the groove is 0.0 [mu] m is defined as the end of the groove, and the distance from the imaginary line to the groove is defined as the distance from the imaginary line to the straight line in the thickness direction of the base steel sheet. When a region 5 mm from an end of the groove toward a center portion in a groove length direction is defined as a groove end portion, a depth of the groove at a plurality of positions of the groove end portion and a width of the groove satisfy a predetermined relationship.

Description

Technical Field

[0001] This invention relates to oriented electromagnetic steel sheets and their manufacturing methods.

[0002] This application claims priority based on Japanese Patent Application No. 2023-111726, filed in Japan on July 6, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] Oriented magnetic steel sheets are soft magnetic materials, mainly used as core materials for transformers. Therefore, oriented magnetic steel sheets require magnetic properties such as high magnetic flux density and low iron loss.

[0004] Iron loss is the energy lost as heat when an iron core is energized using an alternating magnetic field. From an energy-saving perspective, iron loss should be as low as possible. The level of iron loss is affected by factors such as magnetic susceptibility, plate thickness, film tension, impurity content, resistivity, grain size, and domain width. Regarding oriented electromagnetic steel sheets, even with the development of various technologies, research and development to reduce iron loss continues to improve energy conversion efficiency.

[0005] As one method to reduce iron loss, a technique of laser irradiation of steel plates has been proposed. In this technique, strain is introduced onto the surface of the steel plate by laser irradiation, and the magnetic domain width is subdivided, thereby reducing eddy current losses, which are part of iron loss.

[0006] For example, Patent Document 1 discloses a method for manufacturing an orientation-oriented electromagnetic steel sheet that controls magnetic domains by laser irradiation. The method is characterized by the following steps: irradiating the surface of the orientation-oriented electromagnetic steel sheet with a focused continuous-wave laser while scanning in a direction inclined from the rolling direction of the sheet; and repeating the process while staggering the portions of the continuous-wave laser scan at predetermined intervals. The average power of the continuous-wave laser is expressed as P (W), the scanning speed as Vc (mm / s), the predetermined interval as PL (mm), and the input energy Ua is defined as Ua = P / (Vc × PL) (mJ / mm). 2 When ), it satisfies 1.0mm≤PL≤3.0mm and 0.8mJ / mm 2 ≤Ua≤2.0mJ / mm 2 .

[0007] Patent document 1 shows a method to easily reduce iron loss in both the L and C directions of oriented electromagnetic steel sheets while ensuring high productivity.

[0008] However, in the case of manufacturing wound iron cores, stress-relief annealing is required because the oriented electromagnetic steel sheet is shaped by bending. Therefore, in the method of introducing strain into the surface by laser irradiation as described above, the strain introduced into the oriented electromagnetic steel sheet is released by stress-relief annealing. As a result, the effect of magnetic domain subdivision based on laser irradiation is lost.

[0009] Therefore, a scheme was proposed to reduce eddy current losses by forming grooves on the surface of the steel plate, thereby subdividing the magnetic domain width in the same way as strain introduction. In this case, the grooves will not disappear even after stress-relief annealing, and therefore the effect of magnetic domain subdivision will not be lost.

[0010] Methods for forming grooves on steel plates include, for example, electrolytic etching, in which grooves are formed on the surface of a grain-oriented electromagnetic steel sheet by electrolytic etching; gear stamping, in which grooves are formed on the surface of a grain-oriented electromagnetic steel sheet by mechanically stamping gears onto the surface of the sheet; and laser irradiation, in which grooves are formed by melting and evaporating the steel sheet (laser irradiation section) by laser irradiation. For example, Patent Document 2 discloses a method for improving the iron loss characteristics of a grain-oriented electromagnetic steel sheet by controlling a laser beam to irradiate and forming a concave portion with a width of less than 0.5 mm and a depth of more than 10 μm in the rolling direction, which is capable of withstanding stress-relief annealing.

[0011] Here, typically in oriented electromagnetic steel sheets, an insulating film is formed on the surface to impart electrical insulation, tensile strength, and heat resistance to the steel sheet. As shown in Patent Document 2, in oriented electromagnetic steel sheets, by forming grooves approximately parallel to the width direction of the steel sheet, the magnetic domain width is subdivided, reducing iron loss. On the other hand, at the ends of the formed grooves along the length direction (near the beginning and end), the width and depth vary compared to the central portion. Therefore, it is difficult to apply the coating solution to all corners of the groove ends, resulting in areas where the insulating film adhesion is sometimes insufficient. The length of such a region of varying width and depth at the groove ends is relatively small relative to the overall length of the groove, so it is assumed that even if the adhesion of the insulating film is low in this region, the impact on magnetic properties will not be significant. However, in cases where the adhesion of the insulating film is low at the groove ends, the iron substrate is exposed on the surface, which may cause rusting. Furthermore, at such locations where the iron substrate is exposed, interlayer current flows significantly when stacking oriented electromagnetic steel sheets, potentially increasing iron loss.

[0012] However, Patent Document 2 did not study the exposure of such iron base and the formation of rust.

[0013] As a technique for controlling the shape of the end of the groove, for example, Patent Document 3 discloses the following technique: In a method for manufacturing an oriented silicon steel sheet in which linear or dotted grooves are formed on the surface of a steel strip, etching of the end of the steel strip in the width direction is suppressed, and the groove depth at the end in the width direction is less than 70% of the groove depth at the center in the width direction.

[0014] In addition, as a technology to improve the sealing and rust resistance of the insulating film at the end of the groove, for example, Patent Document 4 discloses an orientation electromagnetic steel plate in which the first angle θ formed by the steel plate surface and the straight line at the end of the groove and the aspect ratio A obtained by dividing the average groove depth D by the average groove width W satisfy θ < -21×A+77.

[0015] In addition, Patent Document 5 discloses an orientation-oriented electromagnetic steel sheet, which includes linear grooves formed along a direction intersecting the rolling direction on one or both sides of the electromagnetic steel sheet. The grooves include an inclined portion (GS) and a flat portion (US) in a cross section containing the length direction of the grooves and the normal direction of the rolled surface of the steel sheet. The lengths of the inclined portion and the flat portion satisfy a specified relationship.

[0016] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 4669565 Patent Document 2: Japanese Patent Application Publication No. 6-57335 Patent Document 3: Japanese Patent No. 4016431 Patent Document 4: Japanese Patent No. 6418322 Patent Document 5: Japanese Patent Application Publication No. 2022-503782 Summary of the Invention

[0017] The problem that the invention aims to solve

[0018] However, in Patent Document 3, the etching at the width end of the steel strip is suppressed so that the groove depth at the width end is less than 70% of the groove depth at the center of the width direction. This is to prevent the steel strip from breaking in subsequent processes when a linear groove is introduced by electrolytic etching. However, the sealing and rust resistance of the insulating film at the groove end are not mentioned.

[0019] Furthermore, Patent Document 4 makes no mention of the width and depth of the groove at the end of the groove. The inventors conducted research and found that this may not necessarily improve the sealing and rust resistance of the insulating film at the end of the groove.

[0020] Furthermore, Patent Document 5 makes no mention of the width of the groove at the end of the groove. The inventors conducted research and found that this may not necessarily improve the sealing and rust resistance of the insulating film at the end of the groove. Additionally, it is known that this may not necessarily suppress the reduction in magnetic flux density caused by the formation of the groove.

[0021] As mentioned above, in the past, techniques for improving the sealing and rust resistance of the insulating film at the end of the slot have been proposed in the oriented electromagnetic steel sheet for magnetic domain subdivision based on slot formation, but it cannot be said that sufficient research has been carried out.

[0022] Therefore, the objective of this invention is to provide an oriented electromagnetic steel sheet that exhibits high adhesion of the insulating film even at the end of the groove and excellent rust resistance.

[0023] means for solving problems

[0024] The inventors have studied a method for improving the adhesion of insulating films at the ends of grooves. The results show that by making the groove shape shallower and narrower towards the front end along the groove's length direction, and by forming a shape in which the depth and width satisfy a certain relationship, the adhesion and rust resistance of the insulating film, etc., are improved.

[0025] This invention is based on the above-mentioned insights. The main points of this invention are as follows.

[0026] [1] One aspect of the present invention provides an orientation-type electromagnetic steel sheet comprising a base steel sheet, a forsterite film optionally formed on the base steel sheet, and an insulating film formed on the base steel sheet or the forsterite film. The base steel sheet has a plurality of grooves extending in a direction intersecting the rolling direction. The extension direction of the grooves is defined as the groove length direction. The distance from the imaginary line extending from the surface of the base steel sheet to the groove in the thickness direction of the base steel sheet is defined as the groove depth. The width of the groove in the rolling direction is defined as the groove width. The position where the groove depth is 0.0 μm is defined as the end of the groove. The region 5 mm from the end of the groove towards the center in the groove length direction is defined as the groove end. The groove depth at a position 1 mm from the end of the groove in the groove length direction, in units of μm, is defined as D1, and the groove width is defined as W1. The groove depth at a position 2 mm from the end of the groove is defined as D1. When the depth is set to D2, the width of the groove to W2, the depth of the groove at a position 3mm from the end of the groove to D3, and the width of the groove to W3, the depth of the groove at a position 4mm from the end of the groove to D4, and the width of the groove to W4, the depth of the groove at a position 5mm from the end of the groove to D5, and the width of the groove to W5, and the average width of the groove at the center of the groove along its length to Wc, and the average depth of the groove to Dc, then the aforementioned D1, upper... The above D2, D3, D4, D5, W1, W2, W3, W4 and W5 satisfy the following formula (1) and the following formula (2). At the end of the above groove, when the width of the groove in the part where the depth of the groove is 0.05×Dc is set to W0.05, and the width of the groove in the part where the depth of the groove is 0.50×Dc is set to W0.50, W0.05 and W0.50 satisfy the following formula (3) and the following formula (4). D5≥D4≥D3≥D2≥D1…(1) W5≥W4≥W3≥W2≥W1…(2) 0.004≤W0.05 / Wc≤0.210…(3) 0.180≤W0.50 / Wc≤0.810…(4)

[0027] [2] According to the orientation electromagnetic steel sheet described in [1], the above W0.05 and the above W0.50 can satisfy the following equations (5) and (6). 0.008≤W0.05 / Wc≤0.160…(5) 0.380≤W0.50 / Wc≤0.710…(6)

[0028] [3] According to the oriented electromagnetic steel sheet described in [1], D1, D2, D3, D4 and D5 can satisfy the following formula (1'). D5>D4>D3>D2>D1…(1')

[0029] [4] According to the oriented electromagnetic steel sheet described in [2], D1, D2, D3, D4 and D5 can satisfy the following formula (1'). D5>D4>D3>D2>D1…(1')

[0030] [5] The oriented electromagnetic steel sheet according to any one of [1] to [4] may have a Dc of 5.0 to 40.0 μm and a Wc of 10.0 to 200.0 μm.

[0031] [6] The oriented electromagnetic steel sheet according to any one of [1] to [4] may be such that the interval between the rolling directions of the plurality of grooves is 2 to 10 mm, and the angle between the length direction of the groove and the rolling direction is 60 to 120 degrees.

[0032] [7] According to the oriented electromagnetic steel plate described in [5], the interval between the rolling directions of the plurality of grooves is 2 to 10 mm, and the angle between the length direction of the groove and the rolling direction is 60 to 120 degrees.

[0033] [8] A method for manufacturing an orientation-oriented electromagnetic steel sheet according to one aspect of the present invention comprises: a groove forming step, wherein a steel sheet is scanned along a direction intersecting the rolling direction while being irradiated with a laser to form a groove extending along the rolling direction; a decarburizing annealing step, wherein the steel sheet after the groove forming step is subjected to decarburizing annealing; a final annealing step, wherein the steel sheet after the decarburizing annealing step is subjected to final annealing; and an insulating film forming step, wherein the steel sheet after the final annealing step, which becomes a base steel sheet, is subjected to a process of forming an insulating film to obtain a base steel sheet, a magnesium olivine film optionally formed on the base steel sheet, and a film formed on the base steel sheet or the above-mentioned... Oriented electromagnetic steel sheet with an insulating film on a magnesium olivine film; in the groove forming process, the extension direction of the groove is taken as the groove length direction, the distance from the imaginary line extending from the surface of the base steel sheet to the thickness direction of the base steel sheet is taken as the groove depth, the width of the groove in the rolling direction is taken as the groove width, the position where the groove depth is 0.0 μm is taken as the groove end, the area 5 mm from the groove end toward the center in the groove length direction is taken as the groove end point, and the distance from the groove end point in the groove length direction, in units of μm, is taken as the groove length direction. When the depth of the groove at a position 1mm from the end of the groove is set to D1 and the width of the groove to W1, the depth of the groove at a position 2mm from the end of the groove is set to D2 and the width of the groove to W2, the depth of the groove at a position 3mm from the end of the groove is set to D3 and the width of the groove to W3, the depth of the groove at a position 4mm from the end of the groove is set to D4 and the width of the groove to W4, the depth of the groove at a position 5mm from the end of the groove is set to D5 and the width of the groove to W5, and the average width of the groove at the center of the groove along its length is set to Wc and the average depth of the groove is set to Dc, at the end of the groove, by adjusting the distance from the end of the groove... The distance between the ends of the groove is such that the distance between the laser focus and the surface of the base steel plate varies, such that D1, D2, D3, D4, D5, W1, W2, W3, W4 and W5 satisfy the following formulas (1) and (2), and at the ends of the groove, when the width of the groove is set to W0.05 for the portion where the depth of the groove is 0.05×Dc, and the width of the groove is set to W0.50 for the portion where the depth of the groove is 0.50×Dc, W0.05 and W0.50 satisfy the following formulas (3) and (4) to irradiate the laser and form the groove. D5≥D4≥D3≥D2≥D1…(1) W5≥W4≥W3≥W2≥W1…(2) 0.004≤W0.05 / Wc≤0.210…(3) 0.180≤W0.50 / Wc≤0.810…(4)

[0034] [9] According to the manufacturing method of the oriented electromagnetic steel sheet described in [8], in the above-mentioned groove forming process, the groove can be formed in such a way that W0.05 and W0.50 satisfy the following formulas (5) and (6). 0.008≤W0.05 / Wc≤0.160…(5) 0.380≤W0.50 / Wc≤0.710…(6)

[0035]

[10] According to the manufacturing method of the oriented electromagnetic steel sheet described in [8] or [9], in the above-mentioned groove forming process, as the irradiation conditions of the above-mentioned laser, the output of the above-mentioned laser is set to 200~3000W, the diameter of the laser in the rolling direction including 86% of the above-mentioned output, i.e., the diameter of the focused spot, is set to 10~1000μm, the diameter of the focused spot in the plate width direction of the above-mentioned laser is set to 10~1000μm, and the scanning speed is set to 2~50m / s, so as to form the above-mentioned groove with Dc of 5.0~40.0μm and Wc of 10.0~200.0μm.

[0036]

[11] According to the manufacturing method of the oriented electromagnetic steel sheet described in [8] or [9], the groove may be formed in the groove forming process in such a way that the interval between the rolling directions of the plurality of grooves is 2 to 10 mm and the angle between the groove length direction and the rolling direction is 60 to 120 degrees.

[0037]

[12] According to the manufacturing method of the oriented electromagnetic steel sheet described in

[10] , the groove can also be formed in the groove forming process in such a way that the interval between the rolling directions of the plurality of grooves is 2 to 10 mm and the angle between the groove length direction and the rolling direction is 60 to 120 degrees.

[0038] Invention Effects

[0039] According to the above-described manner of the present invention, it is possible to obtain an orientation-oriented electromagnetic steel sheet with high adhesion and excellent rust resistance, where the insulating film is also present at the end of the groove. Attached Figure Description

[0040] Figure 1 This is a diagram illustrating an example of the formation of a groove in the oriented electromagnetic steel sheet according to this embodiment.

[0041] Figure 2A This is a schematic diagram of the area including the groove of a cross section of the oriented electromagnetic steel sheet of this embodiment, which is parallel to the rolling direction and the thickness direction.

[0042] Figure 2BThis is a schematic diagram of a cross-section of the oriented electromagnetic steel plate of this embodiment, which is parallel to the plate thickness direction and the extension direction of the groove and passes through the center of the groove width.

[0043] Figure 3A This is a schematic diagram showing the extent of the groove in a cross-section of the oriented electromagnetic steel sheet of this embodiment, after the insulating film has been removed for the purpose of determining the width and depth of the groove. The cross-section is parallel to the rolling direction and the thickness direction.

[0044] Figure 3B This is a schematic diagram of a cross-section of the oriented electromagnetic steel plate of this embodiment, after the insulating film has been removed for the purpose of measuring the width and depth of the groove, parallel to the plate thickness direction and the extension direction of the groove, and passing through the center of the groove width. Detailed Implementation

[0045] An orientation-oriented electromagnetic steel sheet (the orientation-oriented electromagnetic steel sheet of this embodiment) and its manufacturing method according to one embodiment of the present invention will be described.

[0046] like Figure 1 , Figure 2A , Figure 2B As shown, the orientation electromagnetic steel plate 1 of this embodiment includes a base steel plate 2 and an insulating film 3 formed on the base steel plate 2.

[0047] Alternatively, although not illustrated, a forsterite film may be present between the base steel plate 2 and the insulating film 3. That is, the system may include a base steel plate 2, a forsterite film formed on the base steel plate 2, and an insulating film 3 formed on the forsterite film.

[0048] In the orientation-oriented electromagnetic steel sheet 1 of this embodiment, the base steel sheet 2 has a plurality of grooves extending in a direction intersecting the rolling direction. In addition, each of the grooves has a specified shape, which will be described later, in the region extending 5 mm from the end E of the groove towards the center in the groove length direction.

[0049] The following is a detailed explanation.

[0050] In this embodiment, the extension direction of the groove is defined as the groove length direction. The groove depth is defined as the distance from an imaginary line extending from the surface of the base steel plate towards the thickness direction of the base steel plate, to the groove (bottom of the groove). The width of the groove in the rolling direction is defined as the groove width. The position where the groove depth is 0.0 μm is defined as the groove end, and the region extending 5 mm from the groove end towards the center in the groove length direction is defined as the groove end point. Furthermore, the groove depth at a position 1 mm from the groove end point in the groove length direction, measured in μm, is defined as D1, and the groove width as W1; the groove depth at a position 2 mm from the groove end point is defined as D2, and the groove width as W2; the groove depth at a position 3 mm from the groove end point is defined as D3, and the groove width as W3; the groove depth at a position 4 mm from the groove end point is defined as D4, and the groove width as W4; and the groove depth at a position 5 mm from the groove end point is defined as D5, and the groove width as W5. In addition, the average width of the groove at the center of the groove along the length direction is set as Wc, and the average depth of the groove is set as Dc.

[0051] <Oriented Electromagnetic Steel Sheet>

[0052] [Base Material Steel Plate]

[0053] (groove)

[0054] In oriented electromagnetic steel sheets, grooves are formed approximately parallel to the width direction of the steel sheet to reduce iron loss. On the other hand, conventionally, at the ends (near the beginning and end) of the grooves along the length direction, the width and depth change compared to the central part, sometimes resulting in areas where the insulating film does not adhere properly.

[0055] In contrast, in the oriented electromagnetic steel plate 1 of this embodiment, in the region 5 mm from the end E (where the depth of the groove is 0.0 μm) of the groove G formed on the base steel plate 2 toward the center in the groove length direction, i.e., the end of the groove, the depth of the groove becomes shallower as it approaches the front end (end E) in the groove length direction, and the width of the groove becomes narrower. The groove depth and the groove width are formed into a shape that satisfies a specified relationship, thereby improving the tightness of the insulating film.

[0056] More specifically, the groove depths D1 to D5 and groove widths W1 to W5 at positions 1 to 5 mm from the end of the groove satisfy the following equations (1) and (2) (where D5 ≠ D1 and W5 ≠ W1), and at the end of the groove, when the groove width of the portion with a groove depth of 0.05 × Dc is set to W0.05 and the groove width of the portion with a groove depth of 0.50 × Dc is set to W0.50, W0.05 and W0.50 satisfy the following equations (3) and (4), thereby improving the sealing performance of the insulating film, etc. D5≥D4≥D3≥D2≥D1…(1) W5≥W4≥W3≥W2≥W1…(2) 0.004≤W0.05 / Wc≤0.210…(3) 0.180≤W0.50 / Wc≤0.810…(4)

[0057] At the end of the groove, the shape of the groove satisfies equations (1) to (4). The reason for the improved sealing of the insulating film is not yet clear, but it is believed that when equations (1) to (4) are satisfied, the width and depth of the groove at the end of the groove change gradually, making it easy to apply the coating solution to all corners of the groove. In addition, when the above conditions are met, the amount of iron base reduced due to the groove can be reduced, thus also having the effect of increasing the magnetic flux density.

[0058] As described above, in the base steel plate 2 of the oriented electromagnetic steel plate 1 in this embodiment, the depth of the groove becomes shallower and the width of the groove becomes narrower as it approaches the front end in the groove length direction. According to equations (1) and (2), the depth and width of the groove can also change continuously (D5>D4>D3>D2>D1), but there can also be a region where they do not change within a certain range (for example, D5=D4≥D3=D2≥D1).

[0059] It is believed that if equation (1) and / or equation (2) are not satisfied, the depth and width of the groove change drastically at the front end of the groove along the length direction, making it difficult to apply the coating solution in this area, thus reducing the adhesion of the insulating film.

[0060] Furthermore, as shown in equations (3) and (4), in the base steel plate 2 of the orientation electromagnetic steel plate 1 in this embodiment, the width of the groove is also narrowed in the shallow part of the groove.

[0061] It is believed that when equations (3) and / or (4) are not satisfied, that is, when the degree of change of the depth of the groove at the end of the groove is very different from the degree of change of the width of the groove, there is a region where the width of the groove is narrow but the depth of the groove is deep, and it is difficult to apply the coating solution in this region, thus reducing the adhesion of the insulating film.

[0062] W0.05 and W0.50 preferably satisfy equations (3') and (4'), more preferably satisfy equations (5) and (6), and even more preferably satisfy equations (5') and (6'). 0.005≤W0.05 / Wc≤0.200…(3') 0.200≤W0.50 / Wc≤0.800…(4’) 0.008≤W0.05 / Wc≤0.160…(5) 0.380≤W0.50 / Wc≤0.710…(6) 0.010≤W0.05 / Wc≤0.150…(5') 0.400≤W0.50 / Wc≤0.700…(6’)

[0063] In this case, the sealing performance of the insulating film can be further improved.

[0064] The shape of the groove other than the end of the groove is not limited, but it is preferred that the average depth Dc of the groove at the center of the groove in the length direction is 5.0~40.0μm and the average width Wc of the groove is 10.0~200.0μm.

[0065] By setting it to this range, the reduction in iron loss caused by magnetic domain subdivision becomes greater.

[0066] Preferably, the spacing S of the rolling directions RD of the multiple grooves G is 2~10mm. The spacing S of the grooves is the distance from the center of the groove in the width direction to the center of the adjacent groove in the width direction. The spacing of the multiple grooves G does not have to be equal as long as it falls within the above range, but it is preferred to be equal.

[0067] Furthermore, the angle between the extension direction (length direction) of the groove and the rolling direction is preferably 60 to 120 degrees. It is preferable to have a direction approximately orthogonal to the rolling direction, and more preferably 75 to 115 degrees relative to the rolling direction. It is also preferable that the multiple grooves are substantially parallel.

[0068] When the extension direction and spacing of the channels are within the aforementioned range, the iron loss reduction effect is greater. The shape of the channels is not limited; for example, the cross-section can be approximately rectangular or approximately triangular. Alternatively, the cross-section can be an arc shape forming part of a circle, etc.

[0069] The groove extends in a straight line along the width of the oriented electromagnetic steel sheet. The groove can be formed over the entire width of the oriented electromagnetic steel sheet, or it can be formed on a portion of the width.

[0070] The depth (D1~D5) and width (W1~W5) of the groove at the end of the groove were measured using a laser microscope (a 3D laser microscope using a pinhole-based confocal optical system). In the case of oriented electromagnetic steel sheets with an insulating film, the depth and width of the groove on the surface of the base steel sheet after the film has been removed were measured.

[0071] Specifically, firstly, the insulating film on the oriented electromagnetic steel sheet can be removed, for example, by the following method: Immerse the oriented electromagnetic steel sheet with the insulating film in an aqueous sodium hydroxide solution at 80°C for 20 minutes, consisting of 30% by mass NaOH and 70% by mass H₂O, followed by washing with water. Finally, dry it with a warm air blower for 1 minute.

[0072] After removing the insulating film according to the above-described procedure, a measurement cross-sectional curve constituting the groove profile is obtained by using a laser microscope in a section parallel to the plate thickness direction and the groove extension direction, passing through the center of the groove width. After obtaining the cross-sectional curve by applying a low-pass filter with a cutoff value of λs to this measurement cross-sectional curve, a band-pass filter with cutoff values ​​of λf and λc is applied to this cross-sectional curve to remove long-wavelength and short-wavelength components. Thus, as... Figure 3B As shown, a corrugated curve WCL is obtained, which forms the profile of the groove in a cross-section parallel to the plate thickness direction and the groove extension direction and passing through the center of the groove width. A corrugated curve is a type of profile curve suitable for simplifying the shape of the profile itself with smooth lines.

[0073] In the aforementioned corrugated curve WCL, an imaginary line IL is drawn along the extension direction (left-right in the paper) of the groove extending on the surface of the base steel plate. The starting point of the imaginary line IL, i.e., the position where the groove depth is 0.0 μm, is taken as the end E of the groove. At a position 1 mm away from the end E along the extension direction of the groove (right-right in the paper), the straight-line distance between the imaginary line IL and the base steel plate 2 is calculated, and this distance is taken as the groove depth D1.

[0074] Furthermore, after determining the location of the groove depth D1, a measurement cross-sectional curve constituting the groove profile was obtained in a section parallel to the rolling direction and the plate thickness direction using a laser microscope. After applying a low-pass filter with a cutoff value λs to this measurement cross-sectional curve to obtain the cross-sectional curve, a band-pass filter with cutoff values ​​λf and λc was applied to the cross-sectional curve to remove long-wavelength and short-wavelength components, as shown... Figure 3A As shown, the corrugated curve WCT, which forms the profile of the groove in a cross-section parallel to the rolling direction and the plate thickness direction, is obtained. In the corrugated curve WCT, the length of the imaginary line IL extending along the rolling direction on the surface of the base steel plate is determined, and it is taken as the width W1 of the groove.

[0075] Using the same method, at positions 2mm, 3mm, 4mm, and 5mm from end E along the extension direction of the groove, calculate the groove depths D2, D3, D4, and D5, and the groove widths W2, W3, W4, and W5, respectively.

[0076] In addition, the average depth Dc and average width Wc of the groove at the center along the length of the groove were measured using a laser microscope, employing the same method as for the groove depth and width at the ends of the groove. At five arbitrary points along the center (within a range of ±10 mm) along the length of a single groove, the groove depth and width were measured, and their average values ​​were taken as the average depth Dc and the average width Wc of the groove.

[0077] In addition, at the end of the groove, the width W0.05 of the groove where the groove depth is 0.05×Dc and the width W0.50 of the groove where the groove depth is 0.50×Dc were measured using a laser microscope.

[0078] like Figure 3B As shown, based on the corrugated curve WCL that forms the groove profile in a cross-section parallel to the plate thickness direction and the groove extension direction and passing through the center of the groove width, the straight-line distance from the groove end E to the position where the groove depth is 0.05×Dc or 0.50×Dc is calculated. At each position, the measured cross-sectional curve forming the groove profile is obtained in a cross-section parallel to the rolling direction and the plate thickness direction by using a laser microscope. After applying a low-pass filter with a cutoff value λs to the measured cross-sectional curve to obtain the cross-sectional curve, a band-pass filter with cutoff values ​​λf and λc is applied to the cross-sectional curve to remove the long-wavelength and short-wavelength components, resulting in the corrugated curve WCT of the cross-section parallel to the rolling direction and the plate thickness direction. On each corrugated curve WCT, the lengths of the imaginary lines IL extending along the rolling direction on the surface of the base steel plate are calculated and set as W0.05 and W0.50.

[0079] When the base steel plate has multiple grooves, it is preferable to satisfy formulas (1) to (4) in all the grooves. Furthermore, it is more preferable to satisfy formulas (3') and (4'), or formulas (5) and (6), or formulas (5') and (6').

[0080] Under the same conditions, when grooves are formed repeatedly at equal intervals in the rolling direction, it is assumed that as long as one groove satisfies equations (1) to (4), the other grooves also satisfy equations (1) to (4). However, when a groove is formed up to the end of the width of the base steel plate, there is no end E of the groove at the end of the groove, so the above measurement is not performed (the groove is not the object of measurement).

[0081] (Chemical composition)

[0082] There are no restrictions on the chemical composition of the base steel sheet for oriented electromagnetic steel sheets, as long as it is the same as the base steel sheet for known oriented electromagnetic steel sheets. For example, as a chemical composition, by mass%, it may contain Si: 2.50~4.50%, Mn: 0.010~0.150%, C: 0~0.085%, acid-soluble Al: 0~0.065%, N: 0~0.012%, Cr: 0~0.30%, Cu: 0~0.40%, P: 0~0.50%, Sn: 0~0.30%, Sb: 0~0.30%, Ni: 0~1.00%, S: 0~0.015%, Se: 0~0.015%, Bi: 0~0.10%, Nb: 0~0.10%, V: 0~0.10%, Mo: 0~0.10%, Ta: 0~0.10%, W: 0~0.10%, B: 0~0.080%, Ti: 0~0.10%. Alternatively, it may contain the above, with the balance being Fe and impurities.

[0083] The chemical composition of oriented electromagnetic steel sheets (base steel sheets) can be determined using general steel analysis methods. For example, the chemical composition can be determined using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). In the case where the base steel sheet has a forsterite coating and an insulating coating (described later), the chemical composition can be analyzed after removing the insulating coating from the oriented electromagnetic steel sheet using the methods described above, and then removing the forsterite coating using known methods such as pickling. Specifically, for example, a 35mm square (35mm × 35mm) test piece can be taken from the center of the base steel sheet after the coating has been removed, and the analysis can be performed using a Shimadzu ICPS-8100 (measuring device) under conditions based on a pre-prepared standard curve. C and S, which are difficult to determine in ICP-AES, can be determined using the combustion-infrared absorption method, and N can be determined using the inactive gas melting-thermal conductivity method.

[0084] (plate thickness)

[0085] There is no limitation on the thickness of the base steel plate for oriented electromagnetic steel sheets, but it is preferably 0.15~0.30mm. When the thickness of the base steel plate exceeds 0.30mm, the classic eddy current loss increases, and the iron loss increases. On the other hand, when the thickness is less than 0.15mm, the rolling efficiency decreases, which is disadvantageous in terms of productivity and cost.

[0086] [Magnesium olivine membrane]

[0087] [Insulating film]

[0088] The oriented electromagnetic steel sheet of this embodiment may include a base steel sheet and an insulating film formed on the surface of the base steel sheet, but a magnesium olivine film may also be formed on the surface of the base steel sheet. In this case, the insulating film may also be formed on the surface of the magnesium olivine film.

[0089] That is, the orientation electromagnetic steel sheet of this embodiment may include a base steel sheet, a magnesium olivine film formed on the base steel sheet, and an insulating film formed on the magnesium olivine film.

[0090] Magnesium olivine coatings and insulating coatings can be formed on one side or on both sides.

[0091] The forsterite coating is an inorganic coating with magnesium silicate as its main component. The forsterite coating is formed by the reaction of an annealing separating agent containing magnesium oxide (MgO) applied to the surface of the base steel plate during final annealing with the components of the base steel plate surface. It has a composition derived from the annealing separating agent and the base steel plate (more specifically, a composition with Mg2SiO4 as the main component).

[0092] On the other hand, during the final annealing, when using an annealing separator mainly composed of Al2O3, a magnesium olivine film sometimes does not form.

[0093] The insulating film imparts electrical insulation and tension to the oriented electromagnetic steel sheet. By applying tension to the oriented electromagnetic steel sheet, the movement of magnetic domain walls within the sheet becomes easier, thereby reducing the iron loss of the oriented electromagnetic steel sheet.

[0094] In addition to electrical insulation and tensile strength as mentioned above, various properties such as rust resistance, heat resistance, and slip resistance can be obtained from the insulating film.

[0095] In the orientation-oriented electromagnetic steel sheet of this embodiment, the insulating film can be, for example, a known film formed by coating a coating solution with phosphate and colloidal silica as the main components onto the surface of the base steel sheet or magnesium olivine film and then sintering it (the process of forming an insulating film).

[0096] <Manufacturing Method>

[0097] The orientation-oriented electromagnetic steel sheet of this embodiment has the above-mentioned characteristics without depending on the manufacturing method, and its effect can be obtained. However, it is preferred that the manufacturing method includes the following steps, which can be manufactured stably.

[0098] (I) The groove forming process involves forming multiple grooves on a steel plate at specified intervals along the rolling direction, extending in a direction intersecting the rolling direction; (II) Decarburization annealing process: the steel plate formed in the above-mentioned tank process is decarburized and annealed. (III) Final annealing process: The steel plate after the above decarburization annealing process is subjected to final annealing; and (IV) Insulating film forming process: The steel plate that has become the base steel plate after the above-mentioned final annealing process (sometimes a magnesium olivine film is also formed on the base steel plate) is treated to form an insulating film to obtain an oriented electromagnetic steel plate having a base steel plate, an optional magnesium olivine film formed on the base steel plate, and the above-mentioned insulating film formed on the base steel plate or on the magnesium olivine film.

[0099] In addition, the steel plate supplied for the groove forming process, when the steel plate is a cold-rolled steel plate, can be manufactured by a manufacturing method including the following steps.

[0100] (V) Hot rolling process, which involves heating and hot rolling a slab to produce a hot-rolled steel plate; (VI) Hot-rolled steel sheet annealing process: annealing the hot-rolled steel sheet after the above-mentioned hot rolling process; and (VII) Cold rolling process: The hot-rolled steel sheet after the above-mentioned hot-rolled steel sheet annealing process is pickled and cold-rolled to produce a cold-rolled steel sheet.

[0101] The groove forming process, which is characteristic of the oriented electromagnetic steel sheet of this embodiment, will be described. Other processes can be performed by setting known conditions based on the magnetic flux density before groove forming, which is the target, and therefore will be omitted from the description.

[0102] However, in the final annealing process, final annealing is usually performed after applying an annealing separator composed of MgO and Al2O3. For example, when using an annealing separator with MgO as the main component, a forsterite (Mg2SiO4) film is formed. When using an annealing separator with Al2O3 as the main component, sometimes a forsterite film does not form.

[0103] Therefore, the annealing separator can be selected based on whether a magnesium olivine film is required.

[0104] In addition, the chemical composition of the slab supplied for hot rolling can be determined by taking into account the changes in chemical composition in each process, based on the desired chemical composition to be obtained as an oriented electromagnetic steel sheet.

[0105] For example, when the chemical composition of the base steel sheet of the preferred embodiment of this oriented electromagnetic steel sheet is obtained, it is preferable to use a slab having the following chemical composition.

[0106] That is, for the slab, as a chemical composition, by mass%, it may contain Si: 2.50~4.50%, Mn: 0.010~0.150%, C: 0.020~0.100%, acid-soluble Al: 0~0.065%, N: 0.002~0.030%, Cr: 0~0.30%, Cu: 0~0.40%, P: 0~0.50%, Sn: 0~0.30%, Sb: 0~0.30%, Ni: 0~1.00%, S: 0.001~0.050%, Se: 0~0.050%, Bi: 0~0.10%, Nb: 0~0.10%, V: 0~0.10%, Mo: 0~0.10%, Ta: 0~0.10%, W: 0~0.10%, B: 0~0.080%, Ti: 0~0.10%. Alternatively, it can contain the above-mentioned components, with the balance being Fe and impurities.

[0107] (Trench forming process)

[0108] In the groove forming process, for steel plates such as hot-rolled steel plates and cold-rolled steel plates, multiple grooves extending in directions intersecting the rolling direction are formed at predetermined intervals along the aforementioned rolling direction. These grooves extending in directions intersecting the rolling direction can be formed by irradiating a laser while scanning in the direction intersecting the rolling direction. Furthermore, by repeatedly altering the scanning laser portion at predetermined intervals in the rolling direction, multiple grooves are formed at predetermined intervals in the rolling direction.

[0109] When the groove is formed, at the end of the groove, the distance between the laser focus and the surface of the base steel plate is varied according to the distance from the end of the groove, so that D1, D2, D3, D4, D5, W1, W2, W3, W4 and W5 satisfy the following formula (1) and the following formula (2). When the width of the groove at the end of the groove is set to W0.05 for the part with a groove depth of 0.05×Dc and the width of the groove at the end of the groove is set to W0.50 for the part with a groove depth of 0.50×Dc, W0.05 and W0.50 satisfy the following formula (3) and the following formula (4) to irradiate the laser and form the groove.

[0110] The groove is preferably formed in such a manner that W0.05 and W0.50 satisfy the following formulas (3') and (4'), (5) and (6), or (5') and (6').

[0111] By forming grooves that satisfy equations (1) to (4), it is possible to manufacture oriented electromagnetic steel sheets with improved adhesion of the insulating film formed in subsequent processes and excellent adhesion of the insulating film. D5≥D4≥D3≥D2≥D1…(1) W5≥W4≥W3≥W2≥W1…(2) 0.004≤W0.05 / Wc≤0.210…(3) 0.180≤W0.50 / Wc≤0.810…(4) 0.005≤W0.05 / Wc≤0.200…(3') 0.200≤W0.50 / Wc≤0.800…(4’) 0.008≤W0.05 / Wc≤0.160…(5) 0.380≤W0.50 / Wc≤0.710…(6) 0.010≤W0.05 / Wc≤0.150…(5') 0.400≤W0.50 / Wc≤0.700…(6’)

[0112] When forming a groove using laser irradiation, by deviating the laser focus from the surface of the steel plate, the laser energy on the surface of the steel plate decreases, the groove depth becomes shallower, and the groove width becomes narrower. Therefore, the distance between the laser focus and the surface of the base steel plate varies depending on the distance from the end of the groove. That is, at the beginning of laser irradiation of one groove, the laser focus is set to a position deviating from the surface of the steel plate, and the focus is moved to gradually align with the surface of the steel plate as the scan progresses. This allows the groove depth and width to vary within a certain range from the beginning of the groove. Similarly, at the end of laser irradiation of one groove, the laser focus is moved to a position deviating from the surface of the steel plate. This allows the groove depth and width to vary within a certain range from the end of the groove. Furthermore, by changing the laser output, the diameter of the focused spot, and the scanning speed, the groove depth and width can also be varied. The groove depth and groove width can vary independently depending on the changing conditions, so each condition is set in combination such that the groove depth and groove width satisfy equations (1) to (4).

[0113] Methods for moving the focal point of a laser include methods for displacing the position of optical components.

[0114] In the groove forming process, from the viewpoint of magnetic domain subdivision, it is preferable to form a groove with an average depth Dc of 5.0~40.0μm and an average width Wc of 10.0~200.0μm at the center of the groove in the length direction.

[0115] In the groove forming process, there are no restrictions on the laser irradiation conditions, but in areas other than the end of the groove, it is preferable to set the laser output to 200~3000W, set the diameter of the laser spot in the rolling direction that includes 86% of the output to 10~1000μm, set the diameter of the laser spot in the plate width direction to 10~1000μm, and set the scanning speed to 2~50m / s.

[0116] In this case, it is easy to form a groove where Dc and Wc are within the preferred range.

[0117] In addition, in the groove forming process, it is preferable to form the grooves with a spacing of 2 to 10 mm between the rolling directions of the multiple grooves and an angle of 60 to 120 degrees (°) between the groove length direction and the rolling direction.

[0118] In this case, the effect of reducing iron loss becomes greater.

[0119] Example

[0120] A slab with a chemical composition containing, by mass%, 3.30% Si, 0.120% Mn, 0.060% C, 0.028% acid-soluble Al, 0.008% N, 0.050% Cr, 0.040% Cu, 0.010% P, 0.020% Sn, 0.005% Ni, and 0.007% S, with the balance being Fe and impurities, is hot-rolled to produce a hot-rolled steel sheet with a thickness of 2.6 mm.

[0121] The hot-rolled steel sheet was annealed by heating it to 1100°C and holding it for 1 minute.

[0122] The hot-rolled steel sheet after annealing is pickled and cold-rolled to produce a cold-rolled steel sheet with a thickness of 0.22mm.

[0123] For the obtained cold-rolled steel sheet, laser irradiation is performed according to each No. under the various conditions shown in Table 1 to form multiple grooves (the laser irradiation conditions are the same in a single cold-rolled steel sheet). Regarding the ends of the grooves, the depth and width of the grooves are gradually changed by displacing the position of the multifaceted mirror.

[0124] The cold-rolled steel sheet after the groove is formed is decarburized and annealed by heating it to 850°C and holding it for 2 minutes.

[0125] An annealing separating agent with magnesium oxide (MgO) as the main component is coated on a cold-rolled steel sheet after decarburization annealing. The sheet is then heated to 1200°C and subjected to final annealing for 20 hours. As a result, a steel sheet with a magnesium olivine film formed on the surface of the cold-rolled steel sheet (base steel sheet) is obtained.

[0126] Next, a coating solution containing colloidal silica and aluminum phosphate is applied to the forsterite film, and heat treatment is performed at 850°C for 1 minute to form an insulating film. The thickness of the insulating film is 5 μm.

[0127] A sample with a width of 60 mm and a rolling direction of 300 mm was taken from the obtained oriented electromagnetic steel plate. For this sample, a single-plate magnetic property test (SST test) was performed according to JIS C2556 (2015) to measure the magnetic flux density B8 generated when magnetized at 800 A / m.

[0128] A 30mm x 30mm test piece was taken from the end portion of the obtained oriented electromagnetic steel sheet containing the groove. After removing the insulating film using the method described above, as a representative example, for one groove, the average groove depth Dc at the center of the groove along the groove length direction, the average groove width Wc, and the groove depth D1 to D5 and groove width W1 to W5 at various positions 1mm to 5mm from the groove end were measured using the method described above. Furthermore, for the same groove, at the groove end, the groove width W0.05 was measured for the portion where the groove depth is 0.05 x Dc, and the groove width W0.50 was measured for the portion where the groove depth is 0.50 x Dc.

[0129] The results are shown in Table 2.

[0130] The following methods were used to evaluate the sealing and rust resistance of the insulating film of the obtained oriented electromagnetic steel sheet.

[0131] The results are shown in Table 3.

[0132] <Seamless Adhesion of Insulating Film>

[0133] Cut an 80mm × 80mm test piece from the end portion of the obtained oriented electromagnetic steel sheet containing the groove, wind it onto a 20mm diameter round bar, and then flatten it.

[0134] Observe the surface of the flattened test piece, measure the area of ​​the insulating film that has not peeled off from the steel plate relative to the area of ​​the bent part, and calculate the residual area rate of the film (%).

[0135] The insulation film sealing performance of test pieces with a residual film area ratio of 95% or more is evaluated as "Excellent (Ex)", the insulation film sealing performance of test pieces with a residual film area ratio of 90% or more but less than 95% is evaluated as "Good (G)", and the insulation film sealing performance of test pieces with a residual film area ratio of less than 90% is evaluated as "Poor (P)".

[0136] Rust resistance

[0137] A 30mm × 30mm test piece was taken from the end portion of the obtained oriented electromagnetic steel sheet containing the groove. This test piece was placed in an atmosphere of 50°C and 91% humidity for one week, and the evaluation was based on the weight change of the test piece before and after rusting. When rust forms, the weight of the test piece increases; therefore, the smaller the weight increase, the better the rust resistance.

[0138] Specifically, the weight increase will be 1.0 mg / m³. 2 The following test pieces were rated "Excellent (Ex)" for rust resistance, with a weight increase of 5.0 mg / m³. 2 The following test pieces are rated "Good (G)" for rust resistance, provided the weight increase exceeds 5.0 mg / m³. 2 The rust resistance of the test piece was rated as "poor (P)".

[0139]

[0140] As shown in Tables 1 to 3, it is confirmed that forming grooves that satisfy formulas (1) to (4) improves the rust resistance and insulating film adhesion of the oriented electromagnetic steel sheet. In addition, by forming grooves that satisfy formulas (3') and (4'), (5) and (6) or (5') and (6'), an oriented electromagnetic steel sheet with further improved rust resistance and insulating film adhesion can be obtained.

[0141] Explanation of reference numerals in the attached figures 1. Oriented Electromagnetic Steel Sheet 2. Base material steel plate 3. Insulating film G slot End of E slot The depth of groove D (a collective term for D1, D2, D3, D4, D5, and Dc) The width of the W-groove (a collective term for W1, W2, W3, W4, W5, and Wc). IL is an imaginary line extending from the surface of the base steel plate. S-groove spacing RD rolling direction TD board width direction ND: Thickness direction of the base steel plate

[0142] Industrial availability According to the present invention, in an oriented electromagnetic steel sheet with grooves formed on its surface for the purpose of reducing iron loss, rust resistance and the adhesion of the insulating film can be improved. Therefore, by using the oriented electromagnetic steel sheet of the present invention, it is possible to prevent the generation of interlayer currents during the stacking of steel sheets, which would otherwise lead to increased iron loss and poor appearance.

Claims

1. An oriented electromagnetic steel sheet, characterized by, It has a base steel sheet, a forsterite film optionally formed on the base steel sheet, and an insulating film formed on the base steel sheet or the forsterite film, the base steel sheet has a plurality of grooves extending in a direction intersecting a rolling direction, the extending direction of the grooves is taken as a groove length direction, a distance from an imaginary line extending on a surface of the base steel sheet toward a plate thickness direction of the base steel sheet to the groove is taken as a depth of the groove, a width of the groove in the rolling direction is taken as a width of the groove, a position where the depth of the groove becomes 0.0 μm is taken as an end of the groove, and a region 5 mm from the end of the groove toward a central portion in the groove length direction is taken as a groove end portion, a depth of the groove at a position 1 mm from the end of the groove in the groove length direction is taken as D1, a width of the groove is taken as W1, a depth of the groove at a position 2 mm from the end of the groove is taken as D2, a width of the groove is taken as W2, a depth of the groove at a position 3 mm from the end of the groove is taken as D3, a width of the groove is taken as W3, a depth of the groove at a position 4 mm from the end of the groove is taken as D4, a width of the groove is taken as W4, a depth of the groove at a position 5 mm from the end of the groove is taken as D5, and a width of the groove is taken as W5, when an average of the width of the groove at a central portion in the groove length direction is taken as Wc and an average of the depth of the groove is taken as Dc, the D1, the D2, the D3, the D4, the D5, the W1, the W2, the W3, the W4, and the W5 satisfy the following expression (1) and the following expression (2), in the groove end portion, when a width of the groove at a portion where the depth of the groove becomes 0.05 x Dc is taken as W0.05 and a width of the groove at a portion where the depth of the groove becomes 0.50 x Dc is taken as W0.50, the W0.05 and the W0.50 satisfy the following expression (3) and the following expression (4), D5 ≥ D4 ≥ D3 ≥ D2 ≥ D1 … (1) W5 ≥ W4 ≥ W3 ≥ W2 ≥ W1 … (2) 0.004 ≤ W0.05 / Wc ≤ 0.210 … (3) 0.180 ≤ W0.50 / Wc ≤ 0.810 … (4).

2. The grain-oriented electromagnetic steel sheet according to claim 1, characterized in that the W0.05 and the W0.50 satisfy the following expression (5) and expression (6), 0.008 ≤ W0.05 / Wc ≤ 0.160 … (5) 0.380 ≤ W0.50 / Wc ≤ 0.710 … (6).

3. The grain-oriented electromagnetic steel sheet according to claim 1, characterized in that the D1, the D2, the D3, the D4, the D5 satisfy the following expression (1'), D5 > D4 > D3 > D2 > D1 … (1').

4. The grain-oriented electromagnetic steel sheet according to claim 2, characterized in that the D1, the D2, the D3, the D4, the D5 satisfy the following expression (1'), D5 > D4 > D3 > D2 > D1 … (1').

5. The grain-oriented electrical steel sheet according to any one of claims 1 to 4, characterized by The Dc is 5.0 to 40.0 μm, and the Wc is 10.0 to 200.0 μm.

6. The grain-oriented magnetic steel sheet according to any one of claims 1 to 4, characterized in that, The intervals of the rolling direction of the plurality of grooves are 2 to 10 mm, and the angle between the groove length direction and the rolling direction is 60 to 120 degrees.

7. The grain-oriented magnetic steel sheet according to claim 5, characterized in that, The intervals of the rolling direction of the plurality of grooves are 2 to 10 mm, and the angle between the groove length direction and the rolling direction is 60 to 120 degrees.

8. A method of manufacturing an oriented electromagnetic steel sheet, characterized by, It has: a groove forming step of forming grooves extending in the rolling direction by irradiating laser light while scanning a steel sheet in a direction intersecting the rolling direction; a decarburization annealing step of performing decarburization annealing on the steel sheet after the groove forming step; a final annealing step of performing final annealing on the steel sheet after the decarburization annealing step; and an insulating film forming step of performing a treatment for forming an insulating film on the steel sheet after the final annealing step to obtain a grain-oriented magnetic steel sheet having a base steel sheet, a forsterite film optionally formed on the base steel sheet, and the insulating film formed on the base steel sheet or the forsterite film; in the groove forming step, the extending direction of the grooves is taken as the groove length direction, the distance from an imaginary line extending on the surface of the base steel sheet to the depth of the groove in the plate thickness direction of the base steel sheet is taken as the depth of the groove, the width of the groove in the rolling direction is taken as the width of the groove, the position where the depth of the groove becomes 0.0 μm is taken as the end of the groove, and a region 5 mm from the end of the groove toward the center of the groove length direction is taken as the groove end portion, the depth of the groove at a position 1 mm from the end of the groove in the groove length direction is taken as D1, and the width of the groove is taken as W1, the depth of the groove at a position 2 mm from the end of the groove is taken as D2, and the width of the groove is taken as W2, the depth of the groove at a position 3 mm from the end of the groove is taken as D3, and the width of the groove is taken as W3, the depth of the groove at a position 4 mm from the end of the groove is taken as D4, and the width of the groove is taken as W4, and the depth of the groove at a position 5 mm from the end of the groove is taken as D5, and the width of the groove is taken as W5, when the average of the width of the groove at the center of the groove length direction of the groove is taken as Wc, and the average of the depth of the groove is taken as Dc, in the groove end portion, the distance between the focal point of the laser light and the surface of the base steel sheet is changed according to the distance from the end of the groove, so that the D1, the D2, the D3, the D4, the D5, the W1, the W2, the W3, the W4, and the W5 satisfy the following formula (1) and the following formula (2), and At the end of the groove, when the width of the groove is set to W0.05 for the portion where the groove depth is 0.05×Dc, and the width of the groove is set to W0.50 for the portion where the groove depth is 0.50×Dc, the groove is formed by irradiating the laser in a manner that satisfies the following equations (3) and (4). D5≥D4≥D3≥D2≥D1…(1) W5≥W4≥W3≥W2≥W1…(2) 0.004≤W0.05 / Wc≤0.210…(3) 0.180≤W0.50 / Wc≤0.810…(4).

9. The method for manufacturing a grain-oriented electromagnetic steel sheet according to claim 8, characterized in that, In the groove forming process, the groove is formed such that W0.05 and W0.50 satisfy the following equations (5) and (6). 0.008≤W0.05 / Wc≤0.160…(5) 0.380≤W0.50 / Wc≤0.710…(6).

10. The method for manufacturing an orientation-oriented electromagnetic steel sheet according to claim 8 or 9, characterized in that, In the groove forming process, as the irradiation conditions for the laser, the laser output is set to 200~3000W, the diameter of the laser spot (including 86% of the output) in the rolling direction is set to 10~1000μm, the diameter of the laser spot in the plate width direction is set to 10~1000μm, and the scanning speed is set to 2~50m / s. The groove is formed with Dc being 5.0~40.0μm and Wc being 10.0~200.0μm.

11. The method for manufacturing an orientation-oriented electromagnetic steel sheet according to claim 8 or 9, characterized in that, In the groove forming process, the grooves are formed with the rolling directions of the plurality of grooves spaced at intervals of 2 to 10 mm and the angle between the groove length direction and the rolling direction being 60 to 120 degrees.

12. The method for manufacturing an orientation-oriented electromagnetic steel sheet according to claim 10, characterized in that, In the groove forming process, the grooves are formed with the rolling directions of the plurality of grooves spaced at intervals of 2 to 10 mm and the angle between the groove length direction and the rolling direction being 60 to 120 degrees.

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