Technical field
[0001]
　The present invention relates to grain-oriented electrical steel sheet.
　Priority is claimed on Japanese Patent Application No. 2015-086302 filed in Japan on April 20, 2015, which is incorporated herein by reference.
Background technique
[0002]
　Conventionally, as a steel sheet for transformer iron core (core) is oriented electrical steel sheet exhibiting excellent magnetic properties in a particular direction are known. The oriented electrical steel sheet, by a combination of cold rolling process and annealing process, a steel sheet crystal orientation is controlled so that the crystal grains of the easy magnetization axis and the rolling direction coincides. It is desirable iron loss oriented electrical steel sheet is as low as possible.
[0003]
　Iron loss is classified into a eddy current loss and hysteresis loss. Further, the eddy current loss is classified into a classical eddy current loss and abnormal eddy current loss. To reduce the classical eddy current loss, grain-oriented electrical steel sheet insulating film formed on the surface of the crystal orientation as described above is controlled steel (the base steel) is generally known. The insulating coating is not only electrically insulating, also serves to provide tension and heat resistance and the like to the steel sheet. Incidentally, in recent years, are also known oriented electrical steel sheet glass coating film is formed between the steel sheet and the insulating film.
[0004]
　On the other hand, as a method for reducing abnormal eddy current loss, a strain extending in a direction crossing the rolling direction, by forming at a predetermined distance along the rolling direction, to narrow the width of the 180 ° domains (180 ° magnetic domain perform subdivision) magnetic domain control method is known. The magnetic domain control method is classified distortion by non-destructive means and non-destructive magnetic domain control method applied to the steel sheet of the grain-oriented electrical steel sheet, in a destructive magnetic domain control methods such as forming grooves in the surface of e.g. steel that.
[0005]
　When manufacturing a winding core for a transformer using a grain-oriented electrical steel sheet, in order to remove the deformation strain caused by the fact that grain oriented electrical steel sheet is coiled, it is necessary to implement a strain relief annealing treatment is there. When manufacturing the winding core using the grain-oriented electrical steel sheet distortion imparted by non-destructive magnetic domain control method, the distortion is eliminated by the practice of strain relief annealing, domain refining effect (i.e. the abnormal eddy current loss reduction effect) is also lost.
[0006]
　In addition, when manufacturing the winding core using the grain-oriented electrical steel sheet which the grooves are imparted by destructive magnetic domain control method, since the groove by the practice of the strain relief annealing process not lost, to maintain the domain refining effect it can. Thus, for the winding core, disruptive magnetic domain control method is generally employed as a method for reducing abnormal eddy current loss.
[0007]
　For example, as disclosed in Patent Document 1, a method of giving a strain is practically the steel sheet by laser irradiation. In addition, substantially perpendicular to the rolling direction of the grain-oriented electrical steel sheet, when and to form a groove 10 ~ 30 [mu] m to a depth of about a constant period in the rolling direction, the iron loss is reduced. This pole is generated in the circumferential groove by a change in permeability at the air gap of the groove, the interval of 180 ° domain wall and magnetic pole to the source is narrowed, because the iron loss is improved.
[0008]
　The method of forming a groove in the electromagnetic steel sheets, for example, electrolytic etching method for forming a groove on the steel sheet surface oriented electrical steel sheet by electrolytic etching (see Patent Document 2), the steel sheet of mechanically oriented electrical steel gears by pressing on the surface (see Patent Document 3) gears pressing method of forming a groove on the steel sheet surface, the laser irradiation method of melting and evaporation of steel plate (a laser irradiation part) by laser irradiation (see Patent Document 4) and the like.
CITATION
Patent Literature
[0009]
Patent Document 1: Japanese Patent Publication 58-26406 Patent Publication
Patent Document 2: Japanese Patent Publication 62-54873 Patent Publication
Patent Document 3: Japanese Patent Publication 62-53579 Patent Publication
Patent Document 4: Japanese Patent 2003-129135 No.
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　When formed in a direction intersecting the grooves for domain refining in the rolling direction, across from one side edge of the steel plate passing the plate in one direction to the other side edge to form a single groove or increase the groove forming speed, it is necessary to slow down the sheet passing speed of the steel sheet. However, the groove forming speed technically limit exists, also in the sheet passing speed of the steel sheet industrially productively there is a lower limit. Therefore, by using a plurality of grooves forming apparatus, there is a case of forming a plurality of grooves across from one side edge of the steel plate passing the plate to the other side edge along the one direction. However, the case of forming a plurality of grooves across from one side edge of the steel plate on the other side edge, iron loss oriented electrical steel sheet has a problem that not improved stably.
[0011]
　The present invention has been made in view of the above problems, it is excellent in industrial productivity, and aims to provide an oriented electrical steel sheet capable of improving the iron loss.
Means for Solving the Problems
[0012]
　The present invention, in order to achieve the object according to solve the above problems, adopts the following means.
(1) oriented electrical steel sheet according to the first aspect of the present invention, in a direction crossing the rolling direction extends vital groove depth direction steel sheet having become grooved steel surface thickness direction in grain-oriented electrical steel sheet comprising, when viewed the steel sheet surface from the plate thickness direction, has a formed groove groups arranged plurality of said grooves with respect to the sheet width direction, forming the groove group wherein grooves, wherein disposed so as to overlap the grooves adjacent on the projection plane perpendicular to the rolling direction, the groove group are arranged more at a distance with respect to the rolling direction.
　In this oriented electrical steel sheet, the ends of the plate width direction of the steel sheet as a reference end, a first groove the groove adjacent of the plurality of the grooves of the groove group in order close from the reference edge, a second groove, wherein the two groove end of the groove longitudinal direction on the grooves constituting said groove group, the first groove end in order closer to the reference end, and a second groove end, which is projected on the projection plane the contour of the first groove and the first groove longitudinal projection line, the contour of the second grooves which are projected on the projection plane and the second groove longitudinal projection line, the contour of the plurality of grooves constituting the group of grooves average depth average groove group depth D in the unit μm in a and to a depth from said second groove longitudinal the steel sheet surface in the first groove end of the projection beam to said plate thickness direction 0.05 × D a and It becomes the point of the second groove longitudinal projection line as a first point, before the said second groove end of the first groove longitudinal projection line Depth from the steel sheet surface to the thickness direction 0.05 × D A when the point of the first groove longitudinal projection line to be set to the second point, in the projection plane, the second groove longitudinal projection line the distance between the first point and the reference end portion is shorter than the distance between said second point and said reference end portion of the first groove longitudinal projection line, the second groove in the overlap region between the second groove end Metropolitan of the first groove end and said first groove, and the thickness direction of the depth from the first groove the steel sheet surface in the second groove end of the first total depth of the thickness direction of the depth from the steel sheet surface in the first groove end of the two grooves 0.5 × D a is greater than or equal.
[0013]
(2) In the oriented electrical steel sheet according to (1), the overlap of the first groove longitudinal projection line included in the area any point to the P1, the second groove longitudinal included in the overlap region of the projection line point, when the distance from the reference end portion is a point equal to the point P1 and P2, the in the overlap region, the first of said first groove longitudinal projection line from the steel sheet surface of the groove the point and the thickness direction of the depth to the P1, the total depth of the thickness direction of the depth from the steel surface of the second groove to the point P2 of the second groove longitudinal projection line is 0 .5 × D A may be more.
[0014]
(3) oriented electrical steel sheet according to the second aspect of the present invention, in a direction crossing the rolling direction extends vital groove depth direction steel sheet having become grooved steel surface thickness direction a grain-oriented electrical steel sheet comprising, when viewed the steel sheet surface from the plate thickness direction, has a formed groove groups arranged plurality of said grooves with respect to the sheet width direction, forming the group of grooves the groove is, the disposed so as to overlap the grooves adjacent on the projection plane perpendicular to the rolling direction, the groove groups are arranged a plurality at a distance with respect to the rolling direction.
　In this oriented electrical steel sheet, a reference end portion of the one end portion of the plate width direction of the steel plate, the grooves adjacent of the plurality of the grooves of the groove group, the order of proximity from the reference end, the as one of the grooves, the second groove, two groove end of the groove longitudinal direction on the grooves constituting said groove group, the order of proximity to the said reference end portion, the first groove end, and a second groove end, the projection surface the contour of the first groove projected to the first groove longitudinal projection line, the contour of the second grooves which are projected on the projection plane and the second groove longitudinal projection line, the first groove longitudinal projection line wherein the steel plate surface average depth toward the plate thickness direction a first groove average depth D in the unit μm of I and a depth extending from the surface of the steel sheet of the second groove longitudinal projection line in the thickness direction of the average value in the unit μm second groove average depth D II the steel sheet in a, the first groove end of the second groove longitudinal projection line Depth direction from the surface to the thickness direction 0.05 × D II the point where the the third point, the plate thickness direction from the surface of the steel sheet in the second groove end of the first groove longitudinal projection line headed depth 0.05 × D I when the point at which the the fourth point, between the at projection plane, wherein the third point and the reference end portion of the second groove longitudinal projection line the distance La is, the shorter than the distance Lb between the first groove longitudinal projection the fourth point and the reference end of line, the second of the first groove end and the first groove of the groove in the overlap region between the second groove end Prefecture, the sum of said thickness direction of depth from the first of said at groove steel sheet surface, from the surface of the steel sheet in the second groove and the depth of the thickness direction depth × 0.25 (D I + D II is) or more.
[0015]
(4) In the oriented electrical steel sheet according to (3), the second the depth from the surface of the steel sheet toward the thickness direction of the channel end of the first groove longitudinal projection line is 0.95 × D I and the becomes point as a fifth point, said second groove longitudinal said first groove end depth toward the thickness direction from the steel sheet surface in the of the projection rays 0.95 × D II to become point the sixth point and when the distance Lc between said fifth point and said reference end portion of the first groove longitudinal projection line is between the second groove longitudinal projection the point and the reference end of the sixth line it may be shorter than the distance Ld between.
[0016]
(5) In the oriented electrical steel sheet according to any one of the above (1) to (4), the particle size of the crystal grains may be 5μm or more in contact with the groove in the steel sheet.
Effect of the invention
[0017]
　According to this aspect of the present invention, it is possible to provide an excellent grain-oriented electrical steel sheet iron loss.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
FIG. 1 is a schematic view showing a groove formed on the surface of the steel sheet of oriented electrical steel sheet according to an embodiment of the present invention.
Is a diagram showing the cross-sectional shape of the groove in FIG. 2] A-A line in FIG.
3 is a diagram showing the groove cross-sectional shape in the line B-B shown in FIG.
It is an explanatory diagram relating to Fig. 4 defines the contour of the groove.
FIG. 5 is an explanatory diagram relating to the definition of the contour of the groove.
6 is an explanatory diagram relating to the definition of the first angle.
7 is an explanatory diagram relating to the definition of the first angle.
8 is a diagram showing a groove longitudinal projection line of the groove adjacent the oriented electrical steel sheet according to the present embodiment.
9 is a graph showing the distribution of the total value of the groove depth of the grooves adjacent the oriented electrical steel sheet according to the present embodiment.
[10] The width of the overlapping area as compared with FIG. 8 is a diagram showing a groove longitudinal projection line grooves adjacent vary.
11 is a graph showing the distribution of the total value of the groove depth of the grooves adjacent in the case shown in FIG. 10.
It is a flowchart showing a manufacturing process of a grain-oriented electrical steel sheet according to [12] the present embodiment.
13 is an explanatory diagram relating to a laser irradiation in the groove processing step of the manufacturing process of the grain-oriented electrical steel sheet according to the present embodiment.
FIG. 14 is an explanatory diagram relating to a laser irradiation in the groove processing step of the manufacturing process of the grain-oriented electrical steel sheet according to the present embodiment.
Is an explanatory diagram relating to laser irradiation in FIG. 15 the groove processing step of the manufacturing process of a grain-oriented electrical steel sheet according to the present embodiment.
FIG. 16 is an explanatory diagram relating to a laser irradiation in the groove processing step of the manufacturing process of the grain-oriented electrical steel sheet according to the present embodiment.
It is a graph showing the relationship between the output and the time of the laser beam irradiation in the grooving process by a laser method in [17] the present embodiment.
18 is a diagram showing a groove formed on the surface of the steel sheet of oriented electrical steel sheets of Example 1.
19 is a diagram showing a groove longitudinal projection line of the groove adjacent the groove groups oriented electrical steel sheet according to a modification of this embodiment.
FIG. 20 is a diagram showing a groove longitudinal projection line of the groove adjacent the groove groups oriented electrical steel sheet according to a modification of this embodiment.
21 is a diagram showing a groove longitudinal projection line of the groove adjacent the groove groups oriented electrical steel sheet according to a modification of this embodiment.
22 is a graph showing the distribution of the total value of the groove depth of the grooves adjacent the oriented electrical steel sheet according to a modification of this embodiment.
DESCRIPTION OF THE INVENTION
[0019]
　Hereinafter, with reference to the accompanying drawings preferred embodiments of the present invention will be described. However, the present invention is not limited only to the configuration disclosed in this embodiment, and various modifications are possible without departing from the scope of the present invention. In addition, the numerical limitation range below the lower limit value and the upper limit value is included in the range. However, the numerical limitation range indicated as "super" the lower limit is not included lower limit does not include the upper limit value in the numerical limitation range indicated as "less than" the upper limit value.
[0020]
　Figure 1 is a plan view of a grain-oriented electrical steel sheet 1 according to this embodiment. Figure 2 is a cross-sectional view taken along the line A-A in FIG. Incidentally, in the figure, the directional rolling direction X of the electromagnetic steel sheet 1, a grain-oriented electrical steel sheet 1 in the plate width direction (direction orthogonal to the rolling direction in the same plane) Y, grain-oriented electrical steel sheet 1 in the thickness direction ( the direction) perpendicular to the XY plane is defined as Z. Oriented electrical steel sheet 1 according to this embodiment, the surface of the steel sheet 2a, with a groove 3 for domain refining. 1, when viewed oriented electrical steel sheet according to the present embodiment from a thickness direction Z (hereinafter, may be referred to as "in plan view") is a schematic view showing a groove 3.
[0021]
　As shown in FIG. 1, when viewed groove 3 from a thickness direction Z (when the groove 3 is viewed in plane), the extending direction of the groove 3 (arrow L shown in FIG. 1) that a groove longitudinal direction L. The grooves 3 in plan view, the direction (arrow Q shown in FIG. 1) perpendicular to the groove longitudinal direction L of the groove 3 of a groove width direction Q. Actual directional steel sheet 2a and the groove 3 of the electromagnetic steel sheet, but is not intended to be uniformly formed surface, Figures 1-3 to illustrate the features of the invention, FIGS. 5 8, Figures 18 in Figure 20 is shown schematically. The groove 3, when viewed from a thickness direction Z (when the groove 3 is viewed in plane), may have an arcuate shape. However, in the present embodiment, for convenience of descriptions, it illustrates the groove 3 having a linear shape.
[0022]
　Oriented electrical steel sheet 1 is provided with a cold-rolling treatment and steel sheet crystal orientation is controlled so that the combination of the annealing and the crystal grains of the easy magnetization axis and the rolling direction X coincide (base steel) 2, a steel sheet having a groove 3 on the second surface (steel sheet surface 2a).
[0023]
　Steel plate 2 as chemical components, in mass fraction, Si: 0.8% ~ 7%, C: 0% ultra-0.085%, acid-soluble Al: 0% ~ 0.065%, N: 0% ~ 0.012%, Mn: 0% ~ 1%, Cr: 0% ~ 0.3%, Cu: 0% ~ 0.4%, P: 0% ~ 0.5%, Sn: 0% ~ 0 .3%, Sb: 0% ~ 0.3%, Ni: 0% ~ 1%, S: 0% ~ 0.015%, Se: 0% ~ 0.015%, containing the balance Fe and consisting of impurities.
[0024]
　Chemical components of the steel plate 2, after the integrated crystal orientation {110} in the <001> orientation, i.e., the preferred chemical composition after controlling the Goss texture. Among the above elements, Si and C is a basic element, acid-soluble Al, N, Mn, Cr, Cu, P, Sn, Sb, Ni, S, and Se are a selective element. Additional optional elements are not necessary to limit the lower limit value so may be contained according to the purpose, the lower limit value may be 0%. These selection elements be contained as an impurity, the effect of the present embodiment is not impaired. Steel 2 above, the remainder of the basic elements and selective elements described above may consist of Fe and impurities. Note that the impurities, in producing the steel plate 2 industrially means inevitably mixed elemental ore as a raw material, scrap or from the manufacturing environment and the like.
　Furthermore, it is common to undergo purification annealing during the secondary recrystallization in the electromagnetic steel sheets. Emissions to the outside of the system of the inhibitor-forming element occurs in the purification annealing. In particular N, decrease in concentration pronounced for S, it becomes 50ppm or less. If ordinary purification annealing conditions, 9 ppm or less, more 6ppm or less, if sufficiently performed purification annealing, reaches a degree that can not be detected (1 ppm or less) in the general analysis.
[0025]
　Chemical composition of the steel plate 2 may be measured by general analytical methods of steel. For example, the chemical components of the steel plate 2 may be measured using an ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Specifically, a test piece of 35mm square were taken from the middle position of the steel plate 2 after film removal, ICP emission spectrometer (e.g., Shimadzu Corporation ICPS-8100) were based on a calibration curve prepared in advance by It can be identified by measuring the condition. Incidentally, C and S are combustion - infrared absorption method using, N is the inert gas fusion - can be measured with a thermal conductivity method.
[0026]
　Oriented electrical steel sheet 1 according to this embodiment may have an insulating film on the groove 3 and the surface of the steel sheet 2a (not shown).
[0027]
　It may further comprise a glass coating film (not shown) between the steel sheet surface 2a and the insulating film. Glass coating, for example, forsterite (Mg 2 SiO 4 ), spinel (MgAl 2 O 4 ) and cordierite (Mg 2 Al 4 Si 5 O 16 is constituted by a composite oxide such as). Although details will be described later, the glass coating film, in the recrystallization annealing step is one of the manufacturing processes of the grain-oriented electrical steel sheet 1, a film formed to prevent the seizure occurs in the steel plate 2. Thus, the glass coating film is not an essential element as a component of a grain-oriented electrical steel sheet 1. Insulating coating, for example, containing colloidal silica and phosphate, as well as electrical insulation, tension, has a role to provide corrosion resistance and heat resistance such as a steel plate 2.
[0028]
　Incidentally, the glass coating film and an insulating film of grain-oriented electrical steel sheet 1, for example, can be removed by the following method. Oriented electrical steel sheet 1 having a glass coating film or an insulating film, NaOH: 10% by mass + H 2 O: 90 wt% aqueous sodium hydroxide, immersed for 15 minutes at 80 ° C.. Then, H 2 SO 4 : 10 wt% + H 2 O: 90 wt% aqueous solution of sulfuric acid, 3 minutes at 80 ° C., immersion. Thereafter, HNO 3 : 10 wt% + H 2 O: by 90 wt% nitric acid aqueous solution, washed with a little less than 1 minute immersion at room temperature. Finally, to be a little less than 1 minutes in a drying with a blower of hot air. Note that when removing the glass coating film or an insulating film from oriented electrical steel sheet 1 by the method described above, the shape and roughness of the groove 3 of the steel plate 2, confirmed to be equivalent to prior to forming the glass coating film or an insulating film It is.
[0029]
　Groove 3, as shown in FIG. 1, extends in a direction crossing the rolling direction X, and the depth direction is formed such that the thickness direction Z. Oriented electrical steel sheet 1, when viewed steel sheet surface 2a from a thickness direction Z, has a groove group 30 made up of a groove 3 arranged more to the plate width direction Y. Then, the grooves 3 of the groove group 30, when viewed in a projection plane perpendicular to the rolling direction X (cross-section shown by the dashed line 11a in FIG. 1), is arranged as a groove adjacent to each other overlap.
　This configuration oriented electrical steel sheet 1, in the case of forming a plurality of grooves 3 in the sheet width direction Y, to ensure a state in which the grooves 3 are formed in the plate width direction Y, thereby improving the core loss .
[0030]
　When the one end of the plate width direction Y of the steel sheet as a reference edge 21a, a plurality of grooves 3 which constitute the groove group 30, the first groove 31 in order of proximity to the reference edge portion 21a, second groove 32 are grooves 3n and forming a plurality of first n. The first groove 31, second groove 32, the grooves 3n of the n, as shown in FIG. 1, distribution such that the ends of the grooves 3 adjacent on the projection plane perpendicular to the rolling direction X overlap It is.
　The groove group 30, as shown in FIG. 1, it is preferable that arranged to the rolling direction X is separated from the other groove group 30.
[0031]
　Groove 3, as shown in FIG. 2, at both ends in the groove longitudinal direction L, the inclined portion 5 is formed to be inclined such that the depth becomes deeper toward the surface of the steel sheet 2a to the bottom 4 of the groove 3. Thus, if having an inclined portion 5 at both ends of the groove longitudinal direction L, and is distributing to the end portions of the grooves 3 adjacent as follows overlap, it is effectively improved core loss it can.
　Define the terms in the following description.
[0032]
(Groove average depth D)
　and the depth of the groove 3, refers to the length of the thickness direction Z from the height of the steel sheet surface 2a to the surface of the groove 3 (the bottom 4). Groove average depth D may be measured as follows. When viewed groove 3 from a thickness direction Z (when the groove 3 is viewed in plane), the observation range is set to a part of the groove 3. Observation range, area (i.e., area where the shape of the groove bottom is stable) excluding the end portion in the groove longitudinal direction L of the groove 3 is preferably set to. For example, the observation range is a substantially central portion of the groove longitudinal direction L, may be the observation area such as the length of the groove longitudinal direction L is about 30 [mu] m ~ 300 [mu] m. Next, obtained height distribution in the observation range using a laser microscope (groove depth distribution), the maximum groove depth in the observation area. Similar measurements at least three regions or by changing the observation range, and more preferably carried out at 10 area. Then, an average value of the maximum groove depth in each observation area, which is defined as the groove average depth D. Groove average depth D of the groove 3 in this embodiment, in order to obtain preferred effects of magnetic domain refining, for example, more preferably preferably at 5μm least 100μm or less, if it is 10μm ultra 40μm or less.
　In order to measure the distance between the steel sheet surface 2a and the groove 3 of the surface, it is necessary to measure the position of the steel sheet surface 2a in the thickness direction Z (height) previously. For example, for each of a plurality of locations on the steel sheet surface 2a in each observation range, the position in the thickness direction Z (height) was measured using a laser microscope, the height of the average surface of the steel sheet 2a of the measurement results it may be used as. Further, in the present embodiment, since using the groove widthwise cross section when measuring the groove average width W as described below, the steel sheet surface 2a may be measured from the groove widthwise cross section. Incidentally, when observing the steel sheet sample by the laser microscope, it is preferable the two plate surfaces of the steel sheet sample (observation surface and the rear surface) is substantially parallel.
[0033]
(Average groove width W)
　of the width and the groove 3, the groove opening of the groove widthwise direction Q when viewed groove 3 in cross section (groove width direction cross-sectional or groove widthwise cross section) perpendicular to the groove longitudinal direction L It refers to the length. The average groove width W may be determined as follows. Like the groove average depth D, and when viewed groove 3 from a thickness direction Z (when the groove 3 is viewed in plane), the observation range is set to a part of the groove 3. Observation range, area (i.e., area where the shape of the groove bottom is stable) excluding the end portion in the groove longitudinal direction L of the groove 3 is preferably set to.
　For example, the observation range is a substantially central portion of the groove longitudinal direction L, may be the observation area such as the length of the groove longitudinal direction L is about 30 [mu] m ~ 300 [mu] m. Then, any one place in the observation range using a laser microscope at (e.g., the maximum groove depth of the observation region position), to obtain a groove widthwise cross section perpendicular to the groove longitudinal direction L. Determining the length of the groove opening from the contour curve of the steel sheet surface 2a and the groove 3 appearing in the groove widthwise cross section.
[0034]
　Specifically, after obtaining a profile curve by applying a low pass filter (cut-off value [lambda] s) in the measurement cross section curve MCL forming a contoured surface of the steel sheet 2a and the grooves 3 appear in the groove widthwise cross, the profile curve by applying a bandpass filter (cut-off value .lambda.f, [lambda] c), the undulation forming removal of the longer wavelength component and a shorter wavelength component from the cross section curve, as shown in FIG. 3, the contour of groove 3 in the groove widthwise sectional curve WWC is obtained. Waviness curve is a type of contour curve suitable for simplifying the shape itself of the contour with a smooth line.
[0035]
　As shown in FIG. 3, the groove widthwise on waviness curve WWC groove 3 in a cross section, a depth from the steel sheet surface 2a to the surface of the groove 3 along the thickness direction Z is a groove average depth of the grooves 3 two points to be 0.05 × D to D (third point 33, a fourth point 34) of the line segment connecting between the length (groove opening) W n seek.
　Similar measurements at least three regions or by changing the observation range, and more preferably carried out at 10 area. Then, an average value of the groove opening in the observation area, which is defined as the average groove width W. The average groove width W of the groove 3 in this embodiment, it is preferable to obtain preferred effects of magnetic domain refining, for example, at 10μm or 250μm or less.
　In order to measure the depth from the surface of the steel sheet 2a becomes 0.05 × D, it is necessary to measure the position of the steel sheet surface 2a in the thickness direction Z (height) previously. For example, for each of a plurality of locations on the steel sheet surface 2a of the waviness curve of each groove widthwise cross section, the position in the thickness direction Z (height) was measured, the average value of the measurement results of the steel sheet surface 2a High it may be utilized in Satoshi.
[0036]
(First angle theta)
　and the first angle of the groove 3 theta refers to the angle formed by the end surface of the steel sheet 2a and the groove 3. The first angle θ may be measured as follows. When viewed groove 3 from a thickness direction Z (when the groove 3 is viewed in plane), the observation range setting part comprising an end portion of the groove longitudinal direction L of the groove 3. The groove 3 from a thickness direction Z plan view, the virtual line L of the plurality (n lines) along the groove longitudinal direction L 1 ~ L n virtually set in the observation range (see FIG. 6). Observation range, the region including the end portion of the groove 3 (i.e., the shape of the groove bottom from the beginning of the groove longitudinal direction L of the groove 3 is a region up to and including the region is stable) it is desirable to set the. Next, using a laser microscope (laser type surface roughness measuring instrument) or the like, the height distribution of the grooves 3 in the observation range (groove depth distribution) phantom line L 1 as measured along, shown in FIG. 4 as the measurement sectional curve MCL1 forming the contour of the groove longitudinal direction L of the ends of the grooves 3 are obtained in line with imaginary line L1.
[0037]
　After obtaining the profile curve by applying a low pass filter (cut-off value [lambda] s) to the measured profile curve MCL1 obtained for the imaginary line L1 as described above, the band filter in its cross-section curve (cut-off value .lambda.f, [lambda] c) by applying and removal of long wavelength components and short wavelength components from the profile curve, as shown in FIG. 5, the shape of the waviness curve LWC1 forming the contour of the groove longitudinal direction L of the ends of the grooves 3 along the virtual line L1 obtained by.
[0038]
　As shown in FIG. 5, using the waviness curve LWC1, the thickness direction between the respective positions of the plurality of (n) along the imaginary line L1, the contour surface of the steel sheet 2a and the groove 3 (i.e. waviness curve LWC1) Z distance (depth d1 ~ dn: unit [mu] m) is obtained. Further, the average value of these depths d1 ~ dn (groove depth D1) is obtained. The same measurement technique, for each well of the other virtual lines L2 ~ Ln, groove depth D2 ~ Dn groove end is obtained.
　In order to measure the depth d1 ~ dn from the steel sheet surface 2a, it is necessary to measure the position of the steel sheet surface 2a in the thickness direction Z (height) previously. For example, for each of a plurality of locations on the steel sheet surface 2a in the observation range, the position in the thickness direction Z (height) was measured using a laser microscope, the average value of the measurement results as the height of the steel sheet surface 2a it may be used.
[0039]
　In the present embodiment, among the virtual lines L1 ~ Ln, selects a virtual line which satisfies the condition that the average depth of and the groove along the groove longitudinal direction L is maximized as a groove base line BL. For example, as shown in FIG. 6, of the groove depth D1 ~ Dn obtained for each of the virtual lines L1 ~ Ln, when the groove depth D2 is largest, the virtual line L2 is defined as the groove base line BL that.
[0040]
　As shown in FIG. 7, on the waviness curve based on the groove reference line BL, and a first point 51 to a depth from the surface of the steel sheet 2a toward the thickness direction Z becomes 0.05 × D, the plate from the surface of the steel sheet 2a the straight line depth toward the thickness direction Z is connecting the second point 52 to be 0.50 × D to Mizobata linear 3E. The first angle θ of the groove 3 is defined as the angle of inclination with respect to the steel sheet surface 2a of the groove end straight 3E.
　In order to measure the first angle θ, it is necessary to linearly approximate the steel sheet surface 2a.
　For example, on a waviness curve based on the groove reference line BL, and may be linear approximation regions of only the steel sheet surface 2a except the groove 3. The angle of inclination of this linear approximation steel sheet surface 2a and groove end straight 3E may be measured. In the same manner, at both ends in the groove longitudinal direction L of the groove 3, groove end obtains a straight line 3E and the steel sheet surface 2a and forms the inclination angle (first angle theta).
[0041]
(Grooves lengthwise projection line LWP)
　and the projection plane plane perpendicular to the rolling direction X, if the projection of the contour of the groove longitudinal direction L of the groove 3 on the projection plane, the contour of the groove longitudinal direction L projected onto the projection surface It is defined as a groove longitudinal projection line LWP. Grooves lengthwise projection line LWP may be measured as follows. The groove 3 from a thickness direction Z when viewed in plan, as the observation range, a region including the whole of the groove 3 or the region including the end portion of the groove 3, (i.e., the groove bottom from the beginning of the groove longitudinal direction L of the groove 3 shape to set a region) up to and including the region that is stable. Within the observation range, to set a plurality of virtual lines along the groove longitudinal direction L virtually. Imaginary lines L 1 ~ L n is the thickness direction Z is assumed to be set to an arbitrary height. Then, by the same manner as described above the groove reference line BL, and selects the virtual line groove depth is maximized. The curve obtained when projected on the projection surface a groove depth distribution along the selected virtual line as a whole of the contour (waviness curve) of the groove longitudinal direction L of the groove 3 and the groove longitudinal projection line LWP. The region as an observation range described above, a region including the overlapping ends of the two regions to include the entire groove or two grooves adjacent, the adjacent (i.e., the shape of the groove bottom of one groove are stable, it is preferable that the area groove end of the two grooves adjacent overlap, and the shape of the other groove of the groove bottom to set a region) including the region is stable. The groove end of the two grooves longitudinal direction L of each groove constituting a groove group 30, the order of proximity to the reference edge portion 21a, the first groove end, and the second groove end. Figure 8 is a first groove end 31a and the second groove end 31b of the first groove longitudinal projection line LWP1 of the first groove 31, second groove longitudinal projection line LWP2 first groove end 32a and a second second groove 32 a groove end 32b shown schematically. In order to explain the positional relationship in the sheet width direction Y of the groove between adjacent, 8, of the plurality of grooves 3 in the grain-oriented electrical steel sheet 1 according to this embodiment, two adjacent in the plate width direction Y describe by extracting only grooves 31 and 32.
[0042]
　Oriented electrical steel sheet 1 according to this embodiment, as shown in FIG. 1, a second groove end 31b of the first groove 31 adjacent to the sheet width direction Y, and a first groove end 32a of the second groove 32 It is arranged to overlap the plate width direction Y. In Figure 8, the first groove 31 and second groove 32 adjacent to the sheet width direction Y, when viewed from a thickness direction Z, it exemplified the arrangement in which the ends do not overlap. However, the first groove 31 and second groove 32, when viewed from a thickness direction Z, may overlap end. For example, the first groove 31 and second groove 32, when viewed from a thickness direction Z, if the end portion is completely overlapped, can be regarded as a single groove.
[0043]
　Position of the plate width direction Y of the first groove end 32a of the second groove 32 in the second groove longitudinal projection line LWP2, the second groove end 31b of the plate width direction Y of the first groove 31 in the first groove longitudinal projection line LWP1 so as to be located in the reference end portion 21a side of a position of a groove adjacent to each other overlap in a plate width direction Y. As shown in FIG. 8, in the second groove end 31b and the first groove end is a first groove 31 and second groove 32 and the plate width direction Y between the 32a of the second groove 32 of the first groove 31 it is an overlapping area R.
[0044]
　In the grain-oriented electrical steel sheet 1, forming a plurality of grooves in the plate width direction Y, and, by the grooves 31 and 32 adjacent to each other overlap each other, the grooves 31 and 32 having an inclined portion 5, ..., be used 3n, it is possible to suppress the iron loss low. That is, in order to improve the rust resistance, even groove 3 inclined portions at both ends of the groove longitudinal direction L is formed, arranging a plurality of grooves 3 in the sheet width direction Y, and adjacent to each other by arranging in the both end portions of the groove overlapped in the plate width direction Y, can improve the core loss as in the case where the single forming grooves of uniform depth in the sheet width direction Y.
[0045]
　Oriented electrical steel sheet 1 according to this embodiment can more improve further the following condition is satisfied, the iron loss of the grain-oriented electrical steel sheet.
[0046]
　Distance in the rolling direction X of the first groove 31 adjacent to the plate width direction Y and the second groove 32 (the distance shown in FIG. 1 F1) is rolling direction X of the groove group 30 adjacent to each other in the rolling direction X the distance is set to be smaller than (length F2 shown in FIG. 1). A plurality of grooves 31 and 32 provided in the plate width direction Y, · · ·, the groove group average depth of 3n D A when the in the second groove end 31b of the first groove longitudinal projection line LWP1, the steel sheet surface 2a from the groove longitudinal depth of the thickness direction Z to the contour of the L is 0.05 × D a becomes position (a point on the first groove longitudinal projection line LWP1) of the first groove 31 of the second groove end 31b 0.05 D a position is referred to as a (second point). Similarly, in the first groove end 32a of the second groove longitudinal projection line LWP2, the steel sheet surface 2a of the groove longitudinal depth of the thickness direction Z to the contour of the L is 0.05 × D A is the position (second groove a point) on the longitudinal projection line LWP2 0.05 D of the first groove end 32a of the second groove 32 a is referred to as a position (first point). The first groove end 32a 0.05 D of the second groove 32 A position (second groove longitudinal projection line LWP2 first point on) the distance between the reference end portion 21a of the steel plate 2, the first groove 31 second groove end 31b 0.05 D of the a position to be shorter than the distance between the (first groove longitudinal projection line LWP1 second point on) the reference end portion 21a of the steel plate 2, the first groove 31 a second groove 32 is located when. In order to improve the rust resistance, even groove 3 formed an inclined portion 5 at both ends of the groove longitudinal direction L, by arranging a plurality of grooves 3 in the sheet width direction Y, and adjacent to each other of the groove 31 , one end portions of the 32 by overlapping the plate width direction Y, each of the grooves 31, 32, ..., even shallow end of 3n, a groove of uniform depth in the sheet width direction Y It can improve the core loss in the same manner as in forming.
[0047]
　Furthermore, the following conditions are satisfied, the iron loss of the grain-oriented electrical steel sheet 1 can be further improved.
　The first groove end 32a and an arbitrary point overlapping on the first groove longitudinal projection lines LWP1 included in the region R of between the second groove end 31b of the first groove 31 of the second groove 32 and P1, overlap second groove longitudinal projection line of the points on LWP2 included in the region R, a point distance from the reference edge portion 21a is equal to the point P1 (that same point located in the plate width direction Y between the point P1) and P2 . In the present embodiment, in the overlap region R, the depth of the thickness direction Z from the steel sheet surface 2a of the first groove 31 to the point P1 on the first groove longitudinal projection line LWP1, the steel sheet surface of the second groove 32 2a from the total depth of the depth of the thickness direction Z of the point P2 on the second groove longitudinal projection line LWP2 is 0.5 × D a is greater than or equal. That is, the points P1 and P2 no matter present in the position of the overlap region R in the throat, "total depth 0.5 × D in the A condition that is at least" is satisfied. As shown in FIGS. 8 and 9, in the overlap region R, the depth of the first depth of the groove 31 and second groove 32 at the reference end portion 21a each point equal distance from P (P1, P2) It is added to. The sum of the depth of the depth and the second grooves 32 of the first groove 31 in the point P is, groove group average depth D of the depth of the plurality of grooves formed in the plate width direction Y A to, 0.5 × D a groove 3 is arranged such that the above.
[0048]
　Figure 8 shows a groove longitudinal projection line obtained by projecting the contour of the groove longitudinal direction L the projection plane on the coordinate. Figure 9 is a graph showing the relationship between the position and the total groove depth in the plate width direction Y of the region from the first end 31a of the first groove 31 to the second groove end 32b of the second groove 32. Grooves lengthwise projection line is showing a simplified straight line. A first groove 31 and second groove 32, are overlapped with each other from the respective groove end to the region of the bottom 4 as described in the above embodiment.
　Therefore, as shown in FIG. 8, in the overlap region R, a first groove 31 total groove depth of the second groove 32 is at most groove group average depth D of the plate width direction Y A of doubled approximately, the minimum value of the total groove depth groove group average depth D of the plate width direction Y a substantially equal to.
[0049]
　Compared to the example shown in FIG. 8 shows an example in which the width of the overlap region R of the first groove 31 adjacent to the second groove 32 are different in FIGS. In the example shown in FIG. 10, each region of the inclined portion 5 of the first groove 31 second groove 32 overlap. That is, a first groove longitudinal projection line LWP1 a second groove longitudinal projection line LWP2 are overlapped so as to intersect at each position of the inclined portion 5 of the first groove 31 second groove 32. As shown in FIG. 11, the total groove depth minimum of the overlap region R, the first groove 31 at a distance from the reference edge portion 21a is equal to the points P (P1, P2) and the second groove 32 values groove group average depth D of the plate width direction Y a smaller than. And the minimum value of the total depth of the overlap region R, there is a correlation between arrival core loss oriented electrical steel sheet having the groove group 30. Incidentally, if the first groove 31 and second groove 32 is long overlap so as to satisfy the above conditions, the inclination angle at the groove end of the groove 31, 32 (first angle theta) is the core loss property It does not affect.
[0050]
　That is, in the overlap region R of the first groove 31 and second groove 32, the total value of the depth of the first groove 31 and second groove 32 is 0.5 × D A equal to or greater than in the overlap region R, to ensure no depths inferior to the depth of the bottom 4 is a region that does not overlap. Thus, in the plate width direction Y, suppressing a decrease in magnetic domain refining effect due to a rapid decrease in the depth of the groove portion, thereby improving the iron loss.
[0051]
　More preferably, in the overlap region R of the first groove 31 and second groove 32, the plate width direction Y on the point P (P1, P2) in the depth of the first groove 31 second groove 32 the sum of the depth, the average value (groove group average depth) D of the depth of the plurality of grooves formed in the plate width direction Y of a to, 0.7 × D a adjacent to the above grooves When it is disposed (in the overlap region R total groove depth of the two grooves 31, 32) desired groove depth in the sheet width direction Y in order to improve the core loss is sufficiently obtained, iron loss There can be improved. When the total upper limit of the depth of the plate width direction Y point on P (P1, P2) in the depth of the first groove 31 second groove 32 is no limit, considering the reduction in magnetic flux density, a groove group average depth D a may be two times or less. Further, the sum of the depth of the first depth of the groove 31 and second groove 32 in the P (P1, P2) points on the plate width direction Y, groove group average depth D A When less than twice the, since the amount of variation in the depth of the grooves in the plate width direction Y is suppressed, it can be more effectively and stably improved iron loss.
[0052]
　Oriented electrical steel sheet 1 according to this embodiment, both end portions of the groove longitudinal direction L of the groove 3 (first groove end 31a, 32a, the second groove end 31b, 32 b) when the normal to the surface of the steel sheet 2a, Theory above is sufficient iron loss even if there is no overlap region R is considered to be obtained.
　However, it may be difficult to reliably form a groove having a vertical end face relative to the surface of the steel sheet 2a. Also, if the depth to the surface of the steel sheet 2a to form a groove in excess of 10 [mu] m, tend to change in the shape of the ends of the grooves 3 is large, after the formation of the groove 3, for providing electrical insulation on the surface of the steel sheet 2a when performing coating, it may be difficult to apply the coating agent throughout the ends of the grooves 3. Further, there is a case where the shape of the ends of the grooves 3 adhesion coating agent at the end of the groove 3 in order to rich change occurs places not sufficient, uniform coating is difficult rust resistance of coating agent becomes a problem . In such a case, it may be beveled at both ends of the groove 3. Oriented electrical steel sheet 1 according to this embodiment, by forming the inclined surface on the end portion of the groove longitudinal direction L of the groove 3, to improve the rust resistance and to stabilize the shape of the end portion of the groove 3, and , by overlapping the first groove longitudinal projection line LWP1 and second groove longitudinal projection line LWP2 inclined surface plate width direction Y of the end portion of at least the grooves 3, keeping the iron loss and rust resistance good since it is, preferable.
[0053]
　Oriented electrical steel sheet 1 according to this embodiment may further be implemented with the following conditions are met, and the improvement of rust resistance, both the improvement of iron loss.
[0054]
　Groove 3 provided in the grain-oriented electrical steel sheet 1 according to this embodiment, as shown in FIG. 2, the groove ends 31a, 31b in the groove longitudinal direction L of the groove 3, the angle formed by the groove end straight line 3E and the steel plate surface 2a (the as one angle theta), as the relationship between the aspect ratio a obtained by dividing the groove average depth D in average groove width W satisfies the equation (1) below, the ends of the groove 3 is inclined.
[0055]
　i <-21 × A + 77 · · · (1)
[0056]
　The first angle θ indicating the angle of inclination of the inclined portion 5 is defined on the basis of the aspect ratio A = D / W obtained by dividing the groove average depth D in average groove width W. In general, the more the groove average depth D is large, an improvement in iron loss affected the groove depth, as the average groove width W is small, and with minimal deterioration of the magnetic flux density deteriorates the steel section removed, and iron loss it is possible to improve. That is, the larger the aspect ratio A, can preferably control the magnetic properties. On the other hand, the larger the aspect ratio A, the coating liquid for hardly enters inside the groove, rust resistance deteriorates. In particular, at the groove end of the groove 3, rust resistance deteriorates. Therefore, in order to achieve both the magnetic properties and rust resistance, it is necessary to control together the aspect ratio A and the first angle theta. Specifically, the first angle θ of the groove 3 is out of the scope of the above formula (1), since a large inclination angle of the groove end of the groove 3 with respect to the aspect ratio, the glass coating film or insulated by the groove ends of the grooves 3 coating is less likely to cover the groove 3. As a result, rust is easily generated at the groove end of the groove 3.
[0057]
　That is, in order to suppress the occurrence of rust, as the deep grooves average depth D, it is necessary to reduce the inclination angle (first angle theta) in the groove end. In order to suppress generation of rust, as the average groove width W is narrow, it is necessary to reduce the inclination angle (first angle theta) in the groove end. When the relationship between the groove average depth D average groove width W and the first angle θ satisfies formula (1), an effect that both the magnetic properties improve and the rust resistance is in the groove 3.
[0058]
　Note that equation (1) is a preferred range when the groove average depth D of the groove 3 is not less than 5 [mu] m. If the groove average depth D of the groove 3 is less than 5 [mu] m, small variations in the shape of the end portion of the groove 3, hardly occurs rust resistance problems. On the other hand, there is a case groove average depth D of the groove 3 is not be is less than 5 [mu] m, the first place magnetic domain refining of by forming a groove sufficient. The depth of the upper groove 3 is not particularly limited. However, the thickness of the thickness direction Z of the grain-oriented electrical steel sheet, if the groove average depth D of the groove 3 is 30% or more, the amount of the grain-oriented electrical steel sheet i.e. steel which is a magnetic material is reduced, the magnetic flux there is a possibility that the density is decreased. For example, the typical thickness of the oriented electrical steel sheet winding transformer applications to consideration is 0.35mm or less, the upper limit of the average depth D of the groove 3 may be set to 100 [mu] m. Groove 3 may be formed only on one surface of a grain-oriented electromagnetic steel sheet, it may be formed on both surfaces.
[0059]
　In addition to the above equation (1), it satisfies the following expression (2), it becomes possible to suppress the generation of rust more accurately, preferred.
[0060]
　　　i <32 × A 2 -55 × A + 73;;; (2)
[0061]
　Further, if the groove average depth D is 30μm or less in the range of 15 [mu] m, the first angle θ of the groove ends of the grooves 3, satisfying the equation (3) below relative to the groove average depth D and the average groove width W If, from the viewpoint of improving the rust resistance, and more preferably.
[0062]
　　θ≦０．１２×Ｗ－０．４５×Ｄ＋５７．３９　　・・・（３）
[0063]
　Moreover, the average groove width W is larger than 30 [mu] m, when it is 100μm or less, the first angle θ of the groove end of the groove 3 and satisfies the equation (4) below with respect to the groove average depth D and the average groove width W , from the viewpoint of improving the rust resistance, and more preferably.
[0064]
　　θ≦－０．３７×Ｄ＋０．１２×Ｗ＋５５．３９　　・・・（４）
[0065]
　In grain-oriented electrical steel sheet 1 according to this embodiment, even less 30μm groove average depth D is 15μm or more, the first angle θ is by forming the groove 3 so as to satisfy the above equation (3), the glass coating film or insulating film is uniformly be coated, it is possible to achieve both the magnetic properties and rust resistance.
　Similarly, the average groove width W is not more 30μm ultra 100μm or less, the first angle θ is satisfies the above equation (4) can achieve both magnetic properties and rust resistance. When forming a plurality of grooves oriented electrical steel sheet, in all the grooves, and the above condition is satisfied, high-quality-oriented electrical steel sheet is obtained. However, if the ends of the grooves reaches the end surfaces of the plate width direction Y of a grain-oriented electrical steel sheet, since the At the end of the groove is not inclined portion is formed, the above-mentioned conditions do not apply of course.
[0066]
　The grooves 3, the following glass coating film 5μm average thickness of 0 or more, the average thickness may be arranged with less insulation coating 5μm or 1 [mu] m. In addition, the steel sheet surface 2a, a glass coating film having an average thickness of 0.5μm or more 5μm or less, the average thickness may be arranged with less insulation coating 5μm or 1 [mu] m. Furthermore, the average thickness of the glass coating film at the groove 3 may be thinner than the average thickness of the glass coating on the steel sheet surface 2a.
[0067]
　Incidentally, by adopting the structure that there is no glass film on the groove 3 (i.e. configuration average thickness of the glass coating film is 0 in the grooves 3), a narrower distance between the walls of the opposing grooves (groove width) since it becomes possible, it is possible to further improve the magnetic domain refining effect by the groove 3 (i.e. reducing effect of the abnormal eddy current loss).
[0068]
　Further, in the present embodiment, the glass coating film is not an essential component. Therefore, for the grain-oriented electrical steel sheet which consists only of the steel plate 2 and the insulating film, by applying the above-described embodiment, it is possible to obtain the effect of the rust resistance improvement. The grain-oriented electrical steel sheet which consists only of the steel plate 2 and an insulating film, the groove 3 is formed an average thickness of the 5μm or less of the insulating film over 1 [mu] m, the surface of the steel sheet 2a, the average thickness of 1 [mu] m or more 5μm or less insulation film may be formed.
[0069]
　In the present embodiment, the steel plate 2, it is preferred particle size of the crystal grains in contact with the groove 3 (secondary recrystallized grains) is 5μm or more in average. Although not limit the grain size of the crystal grains in contact with the groove 3 is not particularly limited, the upper limit 100 × 10 3 may μm or less. Surrounding groove 3, when there are molten resolidified region from the formation of the groove 3, the particle size of the crystal grains in contact with the grooves 3 becomes fine.
　In this case, the final crystal orientation {110} <001> may deviate from the orientation becomes high, preferably magnetic properties is more likely to not be obtained. Therefore, the periphery of the groove 3, it is preferred that no melt resolidified region. If there is no molten resolidified region around the grooves 3, grain size of the crystal grains in contact with the groove 3 (secondary recrystallized grains) is 5μm or more in average. Although not limit the grain size of the crystal grains in contact with the groove 3 is not particularly limited, the upper limit 100 × 10 3 may μm or less.
[0070]
　The particle diameter of the crystal grains means the equivalent circle diameter. The particle size of the crystal grains, for example, may be determined by a general grain diameter measuring standard method such as ASTM E112, or EBSD may be obtained by (Electron Back Scattering Diffraction Pattern) method. The crystal grains in contact with the grooves 3 may be observed in the above groove widthwise cross-section or the thickness direction Z perpendicular cross section. Grooves having no melt resolidified region described above, for example, it can be obtained by the manufacturing method described below.
[0071]
　In particular, a groove when viewed groove 3 in the widthwise cross section, less and the thickness plate of the steel plate 2 thickness direction particle size above 5μm of crystal grains present in the bottom of the groove 3 in the steel plate 2 (secondary recrystallized grains) it is preferable that. This feature, in the lower part of the groove 3 in the steel plate 2, the plate thickness direction grain size of crystal grains is meant that there is no fine particle layer of about 1 [mu] m (melting resolidified region).
[0072]
　Next, a manufacturing method of the grain-oriented electrical steel sheet 1 according to this embodiment. Figure 12 is a flowchart showing a manufacturing process of the grain-oriented electrical steel sheet 1. As shown in FIG. 12, the first casting step S01, a mass fraction, Si: 0.8% ~ 7%, C: 0% ultra-0.085%, acid-soluble Al: 0% ~ 0.065 %, N: 0% ~ 0.012%, Mn: 0% ~ 1%, Cr: 0% ~ 0.3%, Cu: 0% ~ 0.4%, P: 0% ~ 0.5%, Sn: 0% ~ 0.3%, Sb: 0% ~ 0.3%, Ni: 0% ~ 1%, S: 0% ~ 0.015%, Se: 0% ~ 0.015%, containing and the balance is supplied to the molten steel continuous casting machine having a chemical composition consisting of Fe and impurities, the slab is issued manufactured continuously. Subsequently, the hot-rolling step S02, with respect to the slab obtained from the casting step S01, after being heated at a predetermined temperature (e.g. 1150 ~ 1400 ° C.), hot rolling is performed on the slabs that. Thus, for example, hot-rolled steel sheet is obtained having a thickness of 1.8 ~ 3.5 mm.
[0073]
　Subsequently, the annealing step S03, with respect to hot-rolled steel sheet obtained from hot rolling step S02, the annealing treatment under predetermined temperature conditions (e.g. conditions of heating at 750 - 1200 ° C. 30 seconds to 10 minutes) There are carried out.
[0074]
　Subsequently, the cold-rolling step S04, after the pickling process is carried out as necessary on the surface of the hot-rolled steel sheet annealing process is performed at the annealing step S03, cold rolling relative to hot-rolled steel sheet It is carried out. Thus, for example, cold rolled steel sheet is obtained having a thickness of 0.15 ~ 0.35 mm.
[0075]
　Subsequently, the decarburization annealing step S05, with respect to cold-rolled steel sheet obtained from the cold-rolling step S04, and a humid atmosphere at a predetermined temperature (e.g., conditions of heating 1-3 minutes at 700 ~ 900 ° C.) heat treatment at medium (i.e., decarburization annealing process) is performed. When such decarburization annealing process is performed, in cold-rolled steel sheet, the carbon is reduced below a predetermined amount, the primary recrystallization structure is formed. Further, in the decarburization annealing step S05, the surface of the cold rolled steel sheet, silica (SiO 2 oxide layer containing)
[0076]
　Then, the annealing separator application step S06, the annealing separator containing magnesia (MgO) as the main component, is applied to the surface (the surface of the oxide layer) of the cold-rolled steel sheet. Subsequently, the final annealing step S07, with respect to cold-rolled steel sheet annealing separator is coated, heat treated under predetermined temperature conditions (e.g. conditions of heating at 1100 ~ 1300 ℃ 20 ~ 24 hours) (i.e., final annealing process) is performed. If such final annealing process is performed, the secondary recrystallization with resulting cold-rolled steel sheets, cold-rolled steel sheet is purified. As a result, has a chemical composition of the steel plate 2 described above, the groove 3 of the cold-rolled steel sheet crystal orientation is controlled so that the crystal grains of the easy magnetization axis and the rolling direction X coincide (i.e. oriented electrical steel sheet 1 steel 2) in a state before forming is obtained.
[0077]
　Further, when such final annealing process as described above is performed, an oxide layer containing silica as a main component reacts with annealing separator containing magnesia as a main component, forsterite on the surface of the steel plate 2 ( mg 2 SiO 4 glass coating film (not shown including) composite oxide or the like) is formed. In the finish annealing step S07, the steel plate 2 is the annealing process is performed finish in a state of being coiled. By glass coating film is formed on the surface of the steel plate 2 during the final annealing process, it is possible to prevent the burn-in steel plate 2 which is coiled occurs.
[0078]
　In the insulating film forming step S08, with respect to the surface of the steel sheet 2a, for example, an insulating coating solution containing colloidal silica and phosphate is coated over the glass coating film. Then, by heat treatment under predetermined temperature conditions (e.g. 840 ~ 920 ° C.) is performed, the insulating film is formed on the surface of the glass coating film.
[0079]
　Then, the grooving step S09, the glass coating film and the steel sheet surface 2a of the insulating film is formed, to form the groove 3. Oriented electrical steel sheet 1 according to this embodiment, it is possible to form a groove laser method, a press machine method, a method of etching or the like. Hereinafter, in the groove forming step S09, a laser method, a press machine method, a method of forming a groove 3 will be described in the case of using the etching method or the like.
[0080]
(Method of forming grooves by a laser method)
　is described a method of forming grooves by a laser method.
　In the groove processing step S09, by applying a laser beam to the surface of the steel sheet glass coating film is formed (one side only), the surface of the steel plate 2, a plurality of grooves 3 extending in a direction crossing the rolling direction X They are formed at predetermined intervals in the rolling direction X.
[0081]
　As shown in FIG. 12, the groove processing step S09, the laser light YL emitted from the laser light source (not shown) is transmitted through the optical fiber 9 to the laser irradiation apparatus 10. The laser irradiation apparatus 10 incorporates a polygon mirror and its rotary drive (both not shown). The laser irradiation apparatus 10, by the rotation of the polygon mirror, and irradiates toward a laser beam YL on the surface of the steel plate 2, the laser beam is scanned YL substantially parallel to the plate width direction Y of the steel plate 2.
[0082]
　Simultaneously with the irradiation of the laser beam YL, assist gas 25 such as air or an inert gas, is blown to the portion of the steel plate 2 that laser light YL is irradiated. The inert gas, for example, nitrogen or argon. Assist gas 25 is responsible for removing the melted or vaporized components from the steel plate 2 by the laser irradiation. By blowing the assist gas 25, since the laser beam YL reaches the stable steel plate 2, a groove 3 is formed stably. Further, by blowing the assist gas 25, the components can be prevented from adhering to the steel plate 2. As a result, the groove 3 along the scan line of the laser beam YL are formed.
[0083]
　While the steel plate 2 is conveyed along the sheet passing direction coinciding with the rolling direction X, the laser light YL is irradiated to the surface of the steel plate 2. Here, as the grooves 3 are formed at predetermined intervals PL along the rolling direction X, the rotational speed of the polygon mirror is controlled synchronously with respect to the conveying speed of the steel plate 2. As a result, as shown in FIG. 13, the surface of the steel plate 2, a plurality of grooves 3 which intersects the rolling direction X, it is formed at predetermined intervals PL along the rolling direction X.
[0084]
　As the laser light source can be used, for example a fiber laser. YAG laser, semiconductor laser, or CO, 2 generally high power laser used in industrial laser or the like may be used as a laser light source. Further, as long as it is possible to form the grooves 3 stably, may be used pulsed laser or a continuous wave laser, a laser light source. As the irradiation conditions of the laser beam YL, e.g., a laser output to 200 W ~ 2000 W, the condensing spot diameter in the rolling direction X of the laser beam YL (diameter containing 86% of i.e. laser output, less 86% diameter abbreviated described) in a 10 [mu] m ~ 1000 .mu.m, focusing spot diameter in the sheet width direction Y of the laser beam YL (86% diameter) in 10 [mu] m ~ 4000 .mu.m, the laser scanning speed 1m / s ~ 100m / s, the laser scanning pitch (interval PL) that is preferably set to 4mm ~ 10mm.
[0085]
　As shown in FIG. 14, the groove processing step S09 of the present embodiment, when the steel sheet 2 conveyed along parallel sheet passing direction TD in the rolling direction X in plan view, the laser scanning direction SD of the laser beam YL ( from a direction having an inclination angle θ2 to the direction) parallel to the sheet width direction Y, the assist gas 25 is injected so as to follow the laser beam YL. Further, as shown in FIG. 15, when viewing the steel sheet 2 is conveyed along the sheet passing direction TD from the plate width direction Y (the laser scanning direction SD), a direction having an inclination angle θ3 with respect to the steel sheet surface 2a from the assist gas 25 is injected so as to follow the laser beam YL. Angle θ2 is preferably set in a range of more than 90 ° less than 180 °, the angle θ3 is preferably set in the range of 1 ° or more 85 ° or less. Further, the flow rate of the assist gas 25 is preferably set in a range of min 10 to 1000 liters.
　Additionally, present in the sheet passing the atmosphere of the steel plate 2, the number of particles having a size of at least 0.5μm is, 1CF is preferably performed in an atmosphere controlled so that the (cubic feet) 10 or more than 10,000 per.
[0086]
　Scanning the laser beam across the entire width of the grain-oriented electrical steel sheet may be performed by one of the scanning device as shown in FIG. 13 may be performed by a plurality of scanning devices as shown in FIG. 16. If the light source is one, it may be a laser beam by dividing a laser beam emitted from the light source. When using a laser irradiation apparatus 10 in a plurality, as shown in FIG. 16, the laser irradiation apparatus 10 in a plurality are arranged at predetermined intervals along the rolling direction X. Further, when viewed from the rolling direction X, so that the laser scanning line of the laser irradiation apparatus 10 do not overlap each other, the position in the sheet width direction Y of the laser irradiation device 10 is set.
[0087]
　By employing such a laser irradiation method, it is possible to form a plurality of grooves 3 on the surface of the steel sheet 2a. By using a plurality of scanning devices, since it is possible to divide into a plurality of illumination areas in the sheet width direction Y, time scanning and irradiation required per one laser beam is shortened. Thus, particularly suitable for high-speed sheet passing facilities. If a plurality of scanning devices are used, the laser device may be provided only one, may be provided one by one for each scan apparatus is a laser beam of a light source coming incident on the scanning device .
[0088]
　The laser beam by a surface of the mirror is scanned on grain-oriented electrical steel sheet, a predetermined length on the grain-oriented electrical steel sheet (for example, 300 mm) groove in is formed in a substantially transverse direction. Irradiation pitch PL of the groove spacing adjacent to the rolling direction X, i.e. the rolling direction X (transporting direction) can be varied by adjusting the line speed VL and irradiation speed. Thus, by using the laser irradiation apparatus, oriented electrical steel sheet to a laser beam uniform scanning interval PL (irradiation pitch, groove spacing) to the rolling direction X irradiation to form a groove in. That is, by irradiating while scanning by condensing the laser beam on the surface of grain-oriented electrical steel sheet in a direction intersecting the substantially vertical direction (conveying direction in the conveying direction of the grain-oriented electrical steel sheet, a vector perpendicular to the transport direction a predetermined length of the groove extending in a direction) containing formed in the conveying direction at predetermined intervals. Grooves 3 are formed, for example, in the range of plus 45 ° minus 45 ° to the direction substantially perpendicular to the conveying direction of the grain-oriented electrical steel sheet.
[0089]
　In scan both ends, the operation of the mirror and is synchronized with by changing the depth of the grooves 3 by changing the output of laser time, the end 31a of the groove 3, to tilt the 31b. That is, as shown in FIG. 17, in the scan direction, is set to change the laser output at the position where the ends of the grooves 3. For example, the groove width of the groove 3 is 100 [mu] m, the groove depth is 20 [mu] m, the irradiation pitch 3 mm, when the scan speed on the steel sheet is 30 m / s, the first angle θ of the groove end to a 60 ° or less, at the end formed at the time of start of forming one groove, the time ΔT that changes the output of the laser and more 0.0004Ms. Thus, the groove 3 inclined at the end of the groove longitudinal direction L of the groove 3 at a first angle θ described above is formed.
[0090]
　Irradiation of the laser beam, for example, as shown in FIG. 13, a predetermined laser beam emitted from the laser device as a light source, the scanning device, the substantially vertical sheet width direction Y in the rolling direction X in the oriented electrical steel sheet It is performed by scanning at intervals PL. At this time, it is blown to sites assist gas such as air or an inert gas laser beam of the directional electromagnetic steel sheet is irradiated. These results, grooves are formed on the laser beam is irradiated portion of the surface of the grain-oriented electrical steel sheet. Rolling direction X coincides with the sheet passing direction.
[0091]
　Temperature oriented electrical steel sheet when performing irradiation of laser beam is not particularly limited. For example, it is possible to perform the irradiation of the laser beam with respect to the grain-oriented electrical steel sheet of about room temperature. A scanning direction of the laser beam does not have to match the strip width direction Y. However, from the viewpoint of subdividing magnetic domains in the long strip shape to the aspects and the rolling direction X in such work efficiency, the scanning direction and the sheet width direction Y and has an angle in the range of 0 ° ~ 90 °, is within 45 ° it is preferable. More preferably the scanning direction and the plate width direction Y is the angle is within 20 °, it is still more preferably within 10 °.
[0092]
(Method of forming grooves by a press machine method)
　illustrating the groove 3 of the grain-oriented electrical steel sheet 1 according to this embodiment a method for manufacturing a press machine method. When forming the groove 3 in the grain-oriented electrical steel sheet by a press machine method to form a groove by a known press machine method using a tooth die made to correspond to the shape of the groove 3. That is, the grooves 3 are formed by using the tooth type which is formed an inclined portion of the same angle as the first angle θ to the ends of the tooth die in the longitudinal direction.
[0093]
(Method of forming grooves by electrolytic etching)
　describes a method of grooves oriented electrical steel sheet 1 according to this embodiment produced by electrolytic etching.
　An insulating film forming step S08 oriented electrical steel sheet 1 on the surface of the later formed by printing or the like etching resist layer is opened portions corresponding to the shape of the groove. Opening of the etching resist layer, the portion corresponding to the groove ends, the groove longitudinal direction lateral direction of the opening width such that the opening width of the end portions is narrower than the central portion of the L is inclined so as to gradually become smaller forming an etching resist. For example, a groove average depth D is 20 [mu] m, a groove widthwise direction Q groove width 50μm of, and to the first angle θ to 55 ° or less, the opening of the etch resist, the opening width of the groove widthwise direction Q It was set equal to or larger than 100 [mu] m, the length of the groove longitudinal direction L of the portion which is inclined to correspond to the groove end portions are formed so as to be 14 [mu] m. As a result, the groove end which opening width is set narrower etch resist inclined portion 5 is formed. Then, using an etching solution (NaCl or the like), a liquid temperature 30 ° C. subjected to 20 second etch process. Subsequently, by removing the etching resist from the oriented electrical steel sheet, forming grooves 3 on the steel sheet surface 2a.
[0094]
　After forming the groove 3 by the groove machining step S09, again, perform the above insulating film forming step and the same processing (re-insulating film forming step S10). The thickness of the resulting insulating coating is 2 ~ 3 [mu] m. Oriented electrical steel sheet according to the present embodiment is obtained as described above.
[0095]
　Steel plate 2 oriented electrical steel sheet 1 manufactured as described above, as chemical components, in mass fraction, Si: 0.8% ~ 7%, C: 0% ultra-0.085%, acid-soluble Al : 0% ~ 0.065%, N: 0% ~ 0.012%, Mn: 0% ~ 1%, Cr: 0% ~ 0.3%, Cu: 0% ~ 0.4%, P: 0 % ~ 0.5%, Sn: 0% ~ 0.3%, Sb: 0% ~ 0.3%, Ni: 0% ~ 1%, S: 0% ~ 0.015%, Se: 0% ~ 0.015%, it contains, with the balance being Fe and impurities.
[0096]
　In the above embodiment, after the insulating film has been formed on the surface of the steel sheet 2a, and illustrates a case of using the manufacturing process of forming a groove 3 on the surface of the steel sheet 2a by the laser irradiation. In this case, the groove 3 just after the laser irradiation is so exposed to the outside, after the formation of the groove 3, again, it is necessary to form an insulating coating on the steel plate 2. However, in the present embodiment, before the insulating film is formed on the surface of the steel sheet 2a, by irradiating a laser beam YL toward the surface of the steel sheet 2a, a groove 3 on the surface of the steel sheet 2a, thereafter, the insulating film the may be adopted a manufacturing process of forming on the steel plate 2. Or, in this embodiment, after the groove 3 is formed on the steel plate 2, the glass coating film or an insulating film may be formed.
[0097]
　Therefore, the grain-oriented electrical steel sheet according to the present embodiment include, but are oriented electrical steel sheet 1 the coating is completed completed and the glass coating film and the insulating film is high-temperature annealing for secondary recrystallization, similarly, oriented electrical steel sheet before the coating of the glass coating film and an insulating film is completed is also included. That is, using the grain-oriented electrical steel sheet according to the present embodiment, as a post-process, may be obtained a final product by performing the formation of the glass film and the insulating film. Incidentally, as described above that, in the case of performing the above-described film removal method, the shape and roughness of the groove 3 after removal of the glass film or an insulating film is equivalent prior to forming the glass coating film or an insulating film There has been confirmed.
[0098]
　In the above embodiment, the groove machining process between the grooving process has been exemplified a case of implementing the (laser irradiation step) S09, cold rolling step S04 and decarburization annealing step S05 after the finish annealing step S07 it may be carried out. That is, by performing laser irradiation and the assist gas injection against cold-rolled steel sheet obtained from the cold-rolling step S04, after forming the grooves 3 on the steel sheet surface 2a of the cold-rolled steel sheet, leaving for the cold-rolled steel sheet charcoal annealing may be performed.
[0099]
　In the present embodiment, the groove longitudinal direction L is the extending direction of the groove 3, an example is a direction crossing the rolling direction X and the sheet width direction Y. However, the extending direction of the groove 3 in the grain-oriented electrical steel sheet 1 according to this embodiment is not limited thereto. For example, even if the groove longitudinal direction L of the groove 3 is not substantially perpendicular to the rolling direction X, it is possible to achieve both the magnetic properties improve and rust resistance.
[0100]
　In the present embodiment, by a groove shape having the features described above, it is possible to improve the rust resistance in the groove 3 of 15μm or more depth on the surface of the steel sheet 2a. Accordingly, the number of grooves 3 formed in the grain-oriented electrical steel sheet 1 is not particularly limited. For example, it may be formed a plurality of grooves 3 in the sheet width direction Y and the rolling direction X.
[0101]
　In the present embodiment, the shape of the groove 3 in a plan view (the shape of the boundary portion between the groove 3 and the steel sheet surface 2a) is shown the example in which elliptical. However, the shape of the groove 3 of the grain-oriented electrical steel sheet 1 is not limited to this. For example, the grooves 3 has an inclined portion at an end portion of the groove longitudinal direction L, as long satisfy the relationship of the above formula (1) may be any shape.
[0102]
　In Figure 3, the shape of the groove 3 as viewed from the groove widthwise direction Q, an example is asymmetrical shape groove width center with a groove widthwise direction Q as a reference. However, the shape of the groove 3 is not limited to this.
[0103]
　Oriented electrical steel sheet 1 according to this embodiment has an effect optionally groove average depth D is 10μm or 50μm or less.
[0104]
　In the present embodiment, the groove longitudinal direction L is the extending direction of the groove 3, an example is a direction crossing is not limited to this to the rolling direction X and the sheet width direction Y, the groove 3 is rolled it may be any structure that extends in a direction intersecting the direction X. For example, even in the direction of the extending direction of the groove 3 is substantially perpendicular to the rolling direction X can be suppressed rust resistance of the groove 3.
[0105]
　Further, grain-oriented electrical steel sheet 1 according to this embodiment, by providing the overlap region into a plurality of grooves between the plate width direction Y, as described above, the grooves 31 and 32 having an inclined surface, · · ·, 3n can be suppressed, the core loss lower using. That is, as in the grain-oriented electrical steel sheet 1 of the present embodiment, even in the grooves 3 formed an inclined surface at both ends of the groove longitudinal direction L in order to improve the rust resistance, a plurality of grooves 3 plate width arranged in the direction Y, and by overlapping the ends of the grooves 3 adjacent to the sheet width direction Y to each other, each of the grooves 31, 32, ..., even shallow end of 3n, uniform depth It can improve the core loss of the groove 3 as in the case where the one formed in the plate width direction Y.
[0106]
(Modification)
　showing a modification of the grain-oriented electrical steel sheet 1 according to this embodiment. Oriented electrical steel sheet 1 according to this embodiment can also be defined as follows from another aspect.
　As shown in FIG. 19, the average value of the depth toward the thickness direction Z from the first groove longitudinal projection lines LWP1 steel sheet 2a is the contour of the first groove 31 which is projected on the projection plane in the unit μm first groove average depth D I and. Second second groove the average value of the depth toward the thickness direction Z in the unit of μm from the steel sheet surface 2a of the longitudinal projection line LWP2 second groove average depth D is the contour of the groove 32 of the projected onto the projection plane II to. The overlap region R of the oriented electrical steel sheet 1 according to this modification, in the projection plane, the depth direction from the surface of the steel sheet 2a of the first groove end 32a of the second groove longitudinal projection line LWP2 in the thickness direction Z There 0.05 × D II and point where the (third point), the second groove end depth toward the thickness direction Z from the steel sheet surface 2a at 31b of the first groove longitudinal projection line LWP1 is 0.05 × D I can also be defined as the distance between the point where the (fourth point).
[0107]
　In oriented electrical steel sheet 1, by forming the grooves 3 so that a plurality of grooves 3 which overlaps the sheet width direction Y to each other, even if the grooves 3 have an inclined portion 5, a low iron loss it can be suppressed. In other words, even groove 3 formed an inclined portion 5 at both ends of the groove longitudinal direction L in order to improve the rust resistance, by arranging a plurality of grooves 3 in the sheet width direction Y, and adjacent grooves 3 both ends by overlapping in the sheet width direction Y, the grooves 3 of uniform depth can be improved core loss as in the case where the one formed in the plate width direction Y of the.
[0108]
　Oriented electrical steel sheet 1 according to this modification, further the following condition is satisfied, the iron loss can be improved more preferably. Specifically, in the projection plane, the distance La between the second groove longitudinal on the projection line LWP2 of the third point and the reference end portion 21a, the above on the first groove longitudinal projection line LWP1 fourth shorter than the distance Lb between the points and the reference end portion 21a. As a result, since it is possible to overlap the ends of the grooves 3 of each other adjacent to reliably plate width direction Y, the iron loss can be preferably improved.
[0109]
　Oriented electrical steel sheet 1 according to this modification, further the following condition is satisfied, the iron loss can be improved more preferably. Specifically, in the projection plane, and set a reference line parallel to the thickness direction Z in the overlap region R, in any of the reference line of the overlap region R, the first groove longitudinal projection line LWP1 and depth toward the thickness direction Z from the steel sheet surface 2a of the total depth of the depth extending from the surface of the steel sheet 2a of the second groove longitudinal projection line LWP2 in the thickness direction Z is in unit [mu] m, 0.25 × (D I + D II is) or more. At this time (D I = D II = D A 0.5 × D in the case of A when it is higher), it is possible to overlap the ends of the grooves 3 mutually securely next to each other in the sheet width direction Y , the iron loss can be preferably improved. In other words, in the overlap region R, the total depth of the first groove longitudinal projection line LWP1 and the second groove longitudinal projection line LWP2 is, 0.25 × (D I + D II when it is) or (D I = D II = D a in the case of the 0.5 × D a when it is higher), can be preferably improved core loss as described above. The total depth of the × 0.35 (D I + D II is preferably set to) or more, the total depth of the × 0.45 (D I + D II and more preferably in a) above.
[0110]
　Second groove end depth toward the thickness direction Z from the steel sheet surface 2a at 31b of the first groove longitudinal projection line LWP1 is 0.95 × D I the point at which the point of the fifth, second groove longitudinal projection line LWP2 thickness direction headed depth Z from the steel sheet surface 2a of the first groove end 32a is 0.95 × D in II and point the point where the sixth. The distance Lc between the first groove longitudinal projection line the fifth point and the reference end portion of the LWP1 the distance between the second groove longitudinal on the projection line LWP2 the sixth point and the reference end portion 21a it may be shorter than Ld. As a result, it is possible to reduce the steel portion to be removed by the formation of grooves 3, it is possible to improve the small suppressed by and iron loss deterioration of magnetic flux density. Furthermore, the distance Lc of the first groove longitudinal projection line LWP1 is, even if the groove between to be shorter than the distance La of the second groove longitudinal projection line LWP2 is overlapping the same effects.
[0111]
　21 from FIG. 19 shows the different widths example of the overlap region R of the first groove 31 and second groove 32. Specifically, in FIG. 19, the bottom portion 4b of the first groove 31 and second groove 32 and is a part of each of the inclined portion 5 and the bottom portion 4a of the first groove 31 and second groove 32 shows an example in which part of the overlap. 20 shows, the first groove 31 and second groove 32, an example in which most of each of the inclined portion 5 overlap each other. That is, the example shown in FIG. 20, a first groove longitudinal projection line LWP1 a second groove longitudinal projection line LWP2 are overlapped so as to intersect with each of the inclined portion 5. Figure 21 is 20 and the first groove longitudinal projection line LWP1 like the second groove longitudinal projection line LWP2 is intersected by each of the inclined portion 5, and, the distance of the first groove longitudinal projection line LWP1 Lc is an example in which grooves each other so as to be shorter than the distance La of the second groove longitudinal projection line LWP2 overlap. Further, in FIG. 22 indicates the total depth profile of the first groove longitudinal projection line LWP1 and the second groove longitudinal projection line LWP2 shown in FIG. 21. As shown in FIG. 22, the total groove depth of the overlap region R in the example shown in FIG. 21, the distance from the reference edge portion 21a and the first groove 31 in the same points P and the second groove 32 the minimum value, 0.5 × (D I + D II (D) smaller than I = D II = D a groove group average depth D in the case of a becomes smaller than). And the minimum value of the total depth of the overlap region R, between the iron loss oriented electrical steel sheet 1 having a groove group 30, a correlation. Incidentally, if the first groove 31 and second groove 32 is long overlap so as to satisfy the above conditions, the inclination angle at the groove ends (first angle theta) does not affect the core loss property.
[0112]
　That is, in the overlap region R, the total groove depth of the first groove 31 and second groove 32, when compared to the depth of the region not overlapping a free depths comparable (0. × 25 (D I + D II when it) or higher), suppressing a decrease in magnetic domain refining effect by a sharp decrease in groove depth, it is possible to improve the core loss.
[0113]
　In the overlap region R, a first groove 31 total groove depth of the second groove 32 is at most D I + D II a (D I = D II = D A average groove group depth in the case of is D a is double the). Further, as described above, the total groove depth, 0.25 × (D even at the minimum I + D II (D a) I = D II = D A 0.5 × D in the case of A becomes) the It is preferred. Upper limit of the total groove depth of the first groove 31 and second groove 32 is not particularly limited, as described above, D up to I + D II a. It is to be noted that the total groove depth of the first groove 31 and second groove 32, 0.75 × (D I + D II ) below, 0.65 × (D I + D II When) or less, the total groove depth since the amount of fluctuation is suppressed, it can be more effectively and stably improved iron loss. These points are the same in the example of a grain-oriented electrical steel sheet as shown in FIG. 21.
Example
[0114]
　Hereinafter, a more detailed explanation of the effect of one embodiment of the present invention through examples, conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the invention is not limited to this single example of conditions. The present invention does not depart from the gist of the present invention, as far as it achieves the object of the present invention may employ various conditions.
[0115]
　Mass fraction で, Si: 3.0%, acid-soluble Al: 0.05%, C: 0.08%, N: 0.01%, Mn: 0.12%, Cr: 0.05%, Cu : 0.04%, P: 0.01%, Sn: 0.02%, Sb: 0.01%, Ni: 0.005%, S: 0.007%, Se: 0.001%, wo comprising shi, remnants ga Fe and impurities び kara Starting from the chemical composition has wo wo suru su ra STAB prepared shi ta. Ko の su ra te between STAB ni Dui shi, heat-pressure application extension project Minoru S02 wo shi, Connecticut wo has a thickness of 2.3mm の suru to heat-pressure casting material prepared as wo shi ta.
[0116]
　Next, with respect to hot-rolled, was subjected to a heat treatment under conditions of 1 minute at a temperature 1000 ° C. (annealing step S03). Performing cold rolling after applying the pickling treatment after heat treatment (cold rolling step S04), to produce a cold rolled material having a thickness of 0.23 mm.
[0117]
　For this cold rolled material were carried out decarburization annealing under conditions of 2 minutes at a temperature 800 ° C. (decarburization annealing step S05).
　On both sides of the decarburization annealing after cold rolling material, magnesia was coated with an annealing separator composed mainly of (annealing separator application step S06). The annealing separator cold rolled material coated was charged into the furnace in a state wound into a coil, carried out 20 hours final annealing step S07 at a temperature 1200 ° C., the glass coating film is formed on the surface of steel sheet locations, the iron was produced.
[0118]
　Next, on the glass coating film, an insulating material composed mainly of aluminum phosphate was applied, the temperature 850 ° C., subjected to baking for 1 minute, to form an insulating film (insulating film forming step S08).
　Subsequently, using a laser, laser scanning pitch (interval PL) is set to 3 mm, the beam diameter is set 0.1 mm, the scanning direction to 0.3 mm, the scanning speed 30 m / s in the rolling direction X, grooves plurality average depth D is 20 [mu] m, an average groove width W is 100 [mu] m, aspect ratio 0.2, the first angle θ is 60 ° in each of the grooves 31, 32, ..., and 3n in the plate width direction Y of the steel sheet surface 2a the formed (groove processing step S09). After grooving step S09, by applying an insulating material composed mainly of aluminum phosphate again, temperature 850 ° C., subjected to baking for 1 minute, to form an insulating film (Re insulating film forming step S10), the grain-oriented electrical steel sheet It was obtained.
[0119]
　Finally obtained steel sheet of the oriented electrical steel sheet (steel sheet in which grooves are formed) is primarily Si: contained 3.0%.
[0120]
　Each groove 31 and 32, · · ·, 3n is the inclination angle θ4 is 15 ° with respect to the plate width direction Y, and a line connecting the groove end 31a and groove end 31b of the groove 31, groove end of the groove 32 is located next to the groove 31 spaced distance G between the lines mutually connecting the 32a and groove end 32b is a 1 mm, is 3mm overlap, and the second groove end 32b of the first groove 31, the first groove end 32a of the second groove 32, the a second groove end 32b of one groove 31, second groove 32 of the first groove end 32a and about the length of a line segment m connecting the 3.4 mm, the angle θ5 with respect to the plate width direction Y of the line segment m to about 150 ° as a, a plurality placed (see Figure 18). In the grooves the longitudinal projection line LWP in the projection plane of the grain-oriented electrical steel sheet 100 of the first embodiment, the first groove end 32a of the second groove 32, the reference end portion 21a side of the second groove end 31b of the first groove 31 position and has an overlap region R. Groove group average depth D of Example 1 A is the 20 [mu] m, the minimum value of the total groove depth in the overlap region R is 20 [mu] m, 0.5 × D A was more. Further, a plurality arranged grooves in the plate width direction Y, and continuously formed is separated at a pitch of 3mm in the rolling direction X.
[0121]
　Minimum value of the total groove depth as in Example 1 were prepared with different Embodiments 2 to 4. That is, Example 2 is the total groove depth minimum 10μm of the overlap region R, Example 3 is the same minimum 15 [mu] m, the fourth embodiment the minimum value are examples of 25μm .
[0122]
(Comparative Example 1)
　In Comparative Example 1, was prepared oriented electrical steel sheets arranged so that there is no groove overlap region R of the same shape as the grain-oriented electrical steel sheet 100 of the first embodiment. That is, the groove average depth D is 20 [mu] m, 100 [mu] m average groove width W is, the aspect ratio of 0.2, but the first angle θ is arranging a plurality of grooves of 60 ° with respect to the sheet width direction Y, the direction of the Comparative Example 1 the groove longitudinal projection line in the projection plane of the electrical steel sheet, arranged as the overlap region R is not formed. In the grooves the longitudinal projection line, the second groove end 31b of the first groove 31 is located at the reference end portion 21a side of the first groove end 32a of the second groove 32, a first groove end 32a of the second groove 32 the inclination angle of a line connecting the second groove end 31b of the first groove 31 is arranged so as to be 75 ° with respect to perpendicular and sheet width direction Y with respect to the groove longitudinal direction L. That is, the minimum value of the total groove depth is 0 .mu.m.
[0123]
(Comparative Example 2)
　In Comparative Example 2, but are arranged by overlapping the same manner grooves as in Example 1, the minimum value of the total groove depth in the overlap region R, 0.5 × D A below It was prepared of grain-oriented electrical steel sheet. That is, Comparative Example 2, the average groove group depth D A is 20 [mu] m, the minimum value of the total groove depth in the overlap region R was prepared oriented electrical steel sheet is 5 [mu] m.
[0124]
　A test piece of 600mm square, including one or more grooves from each oriented electrical steel sheets of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared 30 sheets.
[0125]
　Based on the specific method of the contours, it identified the contour of the groove of Example 1 and Comparative Examples 1 and 2. First, using a non-contact laser rangefinder (Keyence VK-9700), to the grooves of each of Examples and Comparative Examples, the linear L 10 pieces of grooves longitudinally L 1 ~ L 10 two-dimensional height above distribution was measured. Based on the measurement result, the contour of the groove longitudinal cross-section of the groove to give 10 patterns, respectively. 10 pattern grooves longitudinal sectional profile of each to calculate a groove average depth D, the contour of the groove longitudinal sectional groove average depth D was the most deep, and extracted as a representative pattern. A groove average depth D of the representative pattern shown in groove depth D of Table 1.
[0126]
　A plurality of groove groups 30 of Example 1, respectively, the average groove group depth D A was measured a total groove depth of each As a result, groove group average depth D of Example 1 A is 20 [mu] m, the minimum value of the total groove depth in the overlap region R is 20 [mu] m, all 0.5 × D A was more. Minimum value of the total groove depth of the overlap region R and the arrival iron loss is correlated, the minimum value of the total depth Example 1 to form the overlap regions R so that the above 10 [mu] m, reach the iron loss it has been found that can be below 0.75 W / kg. The first angle θ is 30 ° of the groove 3 of Example 1, when it is 45 ° as in Example 1 and the results of the comparison, the grooves 3 adjacent constituting the groove group 30 overlap, and the total the minimum value of the depth is 0.5 × D a equal to or greater than the first angle θ is 30 ° of the groove 3, 45 °, in the case of 60 °, the iron loss were not almost changed.
[0127]
　The test piece 30 sheets of Example 1, the maximum magnetic flux density is 1.7 T, the frequency iron loss W when the AC excitation under the conditions of 50 Hz 17/50 measured (W / kg), the mean value was calculated . Also test piece 30 sheets of Comparative Example 1 were measured in the same manner, to calculate the average value of the iron loss. The average value of the iron loss of the test piece of Example 1 W 17/50 is = 0.72 (W / kg), the average value of the iron loss of the test piece of Comparative Example 1 W 17/50 = 0.80 It became a (W / kg). As a result, towards the oriented electrical steel sheet of Example 1 was superior iron loss than oriented electrical steel sheet of Comparative Example 1.
[0128]
　They were compared for iron loss improvement of Examples 1 to 4 and Comparative Examples 1 and 2. The comparison results are shown in Table 1.
　Evaluation of iron loss improvement measures the iron loss of the steel sheet prior to the grooving of Examples 1-4 and Comparative Examples 1 and 2 (the steel sheet after the insulating film forming step S08), which was used as a reference iron loss, to determine the improvement rate of iron loss with respect to the reference iron loss. As a result, iron loss improvement rate was good results in Examples 2 and 3. Also, Examples 1 and 4, the iron loss improvement rate was obtained 20% and very high results. Comparative Example 1 and Comparative Example 2, the iron loss improvement rate was lower than that in the grain-oriented electrical steel sheet of Examples 1-4.
[0129]
[Table 1]

[0130]
(Examples 5-18)
　using a laser, laser scanning pitch (interval PL) is set to 3 mm, 0.1 mm beam diameter in the rolling direction X, the scanning direction to 0.3 mm, the scanning speed 30 m / s set, were prepared groove average depth D, the groove longitudinal direction L the average groove width W, and oriented electrical steel sheet in which the first angle θ is formed in the groove surface of the steel sheet 2a shown in Table 1 below. As a comparative example, a groove average depth D, the average groove width W of the groove longitudinal direction L, and the first angle θ was prepared oriented electrical steel sheet having grooves as shown in Table 2 below.
[0131]
　Contour in the cross section of the groove widthwise direction Q, using the same non-contact laser rangefinder was measured two-dimensional height distribution of the grooves in the 20 straight lines of the groove widthwise direction Q. Based on the measurement result, the contour of the groove widthwise cross section of the groove to give 20 patterns. In the obtained 20 pattern groove profile in the transverse cross section of a depth from the steel sheet surface 2a to the groove surface (on the contour) was measured to calculate the groove widthwise average depth Ds. In the groove widthwise cross section, the point of the groove widthwise average depth Ds × 0.05 was extracted two points was measured distance two points tube as the groove width W. The average value of the groove width W obtained for each of 20 patterns are calculated as the average groove width. Examples 5-18 and Comparative Examples 3-5 in average groove width of the resulting grain-oriented electrical steel sheet, respectively (unit [mu] m) shown in Table 2.
[0132]
[Table 2]

[0133]
　Examples 5 and 6 is an example that satisfies the relationship only of the formula (1) and (2) described in the above embodiment. Examples 12-18 are examples which satisfy only the relationship of Equation (1) described in the above embodiment. Examples 8 and 9 are examples which satisfy the relationship of formula (4) from equation (1) described in the above embodiment. Example 7, the formulas described above embodiments (1), an example satisfying the relationship of formula (2) and (4). Example 10, wherein according to the above embodiment (1), equation (2), and an example which satisfies the relation of equation (3). Further, Comparative Examples 3-5 were prepared oriented electrical steel sheet which does not satisfy the above formula (1).
[0134]
　Rust resistance evaluation, a test piece 30mm square containing one groove from each oriented electrical steel sheet of the above Examples and Comparative Examples was taken, the test strip, the temperature is 50 ° C., the humidity is 95% or more after standing for 48 hours at sustained indoor confirmed the occurrence of rust in each specimen. Occurrence of rust was visually observed. In addition, for the rust resistance, and the test piece is subjected to a temperature of 50 ° C. and a humidity of 91% and allowed to stand for one week, were assessed on the basis of the weight change of the test piece in the back and forth. Since the weight of the rust test strip is increased, it is determined that there is good rust resistance as having less increase in weight. Specifically, increase in weight is 1.0 mg / m 2 was evaluated as the rust resistance "excellent" in the following test piece, increase in weight is 5.0 mg / m 2 of rust resistance of the following specimen "good" was evaluated as, increase in weight is 10.0 mg / m 2 of rust resistance of greater than specimens were evaluated as "poor". As shown in Table 1, results of verifying the rust resistance of the grain-oriented electrical steel sheet of Examples 5-18, by forming a groove satisfying at least equation (1), rust resistance oriented electrical steel sheet it was confirmed to be improved.

The scope of the claims
[Claim 1]
　In oriented electrical steel sheet having a rolling direction and extending vital groove depth direction in a direction intersecting the steel sheets having become grooves formed steel surface thickness direction,
　as viewed the steel sheet surface from the plate thickness direction when the groove has a plurality arranged which are constructed groove group to the plate width direction,
　said groove constituting the groove group is overlapping with grooves adjacent on the projection plane perpendicular to the rolling direction disposed to,
　the groove group is the arranged plurality at a distance with respect to the rolling direction,
　an end portion of the plate width direction of the steel sheet as a reference end, among the plurality of grooves of said groove group first groove grooves in order of distance from the reference end portion adjacent to the second groove,
　two groove end of the groove longitudinal direction on the grooves constituting said groove group, the order of proximity from the reference edge first groove end, the second groove end and,
　the contour of the first groove projected on the projection plane first groove longitudinal projection And,
　the contour of the second grooves which are projected on the projection plane and the second groove longitudinal projection line,
　groove group average depth in the unit μm an average depth in the edge of the plurality of grooves constituting the group of grooves D a and,
　the second groove longitudinal depth from the steel sheet surface in the first groove end of the projection beam to said plate thickness direction 0.05 × D a becomes the second groove longitudinal projection of the point on the line first and a point,
　said first groove longitudinal depth of the projection lines the second groove end of the steel sheet surface to the thickness direction 0.05 × D a becomes the first groove longitudinal projection of the line of points second when a point,
　in the projection plane, the distance between the second groove longitudinal projection of the first point and the reference end of the line is, with the second point of the first groove longitudinal projection line shorter than the distance between said reference end portion,
　between the second groove end Metropolitan of the second of the first groove end and the first groove of the groove In the overlap region, and the thickness direction of the depth from the steel sheet surface in the second groove end of said first groove, said plate thickness direction from the steel sheet surface in the first groove end of the second groove total depth of the depth 0.5 × D a is greater than or equal
oriented electrical steel sheet, characterized in that.
[Claim 2]
　The overlap of the first groove longitudinal projection line included in the area any point of the P1,
　among the points of said second groove longitudinal projection line included in the overlap region, the distance from the reference end the when a point equal to the point P1 P2,
　in the overlap region, and the thickness direction of the depth from the steel surface of the first groove to the point P1 of the first groove longitudinal projection line, the first the total depth of the thickness direction of the depth from the steel sheet surface to the point P2 of the second groove longitudinal projection line of the second groove is 0.5 × D a claim 1, characterized in that at least oriented electrical steel sheet according to.
[Claim 3]
　A grain-oriented electrical steel sheet having a rolling direction and extending vital groove depth direction in a direction intersecting the steel sheets having become grooves formed steel surface thickness direction,
　the steel sheet surface from the plate thickness direction when viewed, the groove has a plurality arranged which are constructed groove group to the plate width direction,
　said groove constituting the groove group is adjacent on a projection plane perpendicular to the rolling direction groove disposed so as to overlap with,
　the plurality disposed the groove group is at a distance with respect to the rolling direction,
　the one end portion of the plate width direction of the steel sheet as a reference end, a plurality of the groove groups a groove adjacent one of said grooves, in order of increasing distance from the reference end portion, the first groove, the second groove,
　two of groove end of the groove longitudinal direction on the grooves constituting the group of grooves, the in order of distance from the reference end, the first groove end, the second groove end and,
　the contour of the first groove projected to the projection surface and the A groove longitudinal projection line,
　the contour of the second grooves which are projected on the projection plane and the second groove longitudinal projection line,
　from the steel sheet surface of said first groove longitudinal projection line depth toward the plate thickness direction first groove average depth D of the average value in the unit [mu] m I and,
　the second groove longitudinal average depth toward the thickness direction from the surface of the steel sheet projection line with the unit [mu] m second groove average depth D II and,
　the second groove longitudinal projection line the first said depth from the surface of the steel sheet toward the thickness direction of the groove end of 0.05 × D II to the point where the third point,
　the first groove the second the depth from the surface of the steel sheet toward the thickness direction of the groove end of the longitudinal projection line is 0.05 × D I when the point at which the the fourth point,
　in said projection plane, the second the distance La between the third point and the reference end portion of the groove longitudinal projection line is the fourth of the first groove longitudinal projection line Shorter than the distance Lb between said reference end portion,
　in the overlap region between the second groove end Metropolitan of the second of the first groove end and the first groove of the groove in the first groove the depth of the thickness direction from the steel sheet surface, the total depth from the steel sheet surface in the second groove and the depth of the thickness direction 0.25 × (D I + D II is) than
that oriented electrical steel sheet characterized.
[Claim 4]
　The second the depth from the surface of the steel sheet toward the thickness direction of the channel end of the first groove longitudinal projection line is 0.95 × D I the point at which the fifth point,
　the second groove longitudinal projection line from the steel sheet surface in the first groove end depth toward the thickness direction 0.95 × D of II when the point where the the point of the sixth,
　the fifth of the first groove longitudinal projection line the distance Lc between point and the reference end, according to claim 3, characterized in that less than the distance Ld between the point and the reference end of the sixth second groove longitudinal projection line of grain-oriented electrical steel sheet.
[Claim 5]
　Oriented electrical steel sheet according to any one of claims 1 to 4 in the steel sheet, wherein the particle diameter of the crystal grains in contact with the groove is 5μm or more.