Title of invention: grain-oriented electrical steel sheet
Technical field
[0001]
　The present invention relates to grain-oriented electrical steel sheets.
　This application applies to Japanese Patent Application No. 2018-1438998 filed in Japan on July 31, 2018, Japanese Patent Application No. 2018-143900 filed in Japan on July 31, 2018, and to Japan on July 31, 2018. Japanese Patent Application No. 2018-143901 filed, Japanese Patent Application No. 2018-143902 filed in Japan on July 31, 2018, Japanese Patent Application No. 2018-143904 filed in Japan on July 31, 2018, and 2018. Claim the priority based on Japanese Patent Application No. 2018-143905, which was filed in Japan on July 31, 2014, and the contents of which are incorporated herein by reference.
Background technology
[0002]
　The grain-oriented electrical steel sheet is a steel sheet containing 7% by mass or less of Si and having a secondary recrystallization texture accumulated in the {110} <001> orientation (Goss orientation). The {110} <001> orientation means that the {110} plane of the crystal is arranged parallel to the rolling surface, and the <001> axis of the crystal is arranged parallel to the rolling direction.
[0003]
　The magnetic properties of grain-oriented electrical steel sheets are greatly affected by the degree of integration in the {110} <001> orientation. In particular, it is considered that the relationship between the rolling direction of the steel sheet, which is the main magnetization direction when the steel sheet is used, and the <001> direction of the crystal, which is the easy magnetization direction, is important. Therefore, in recent practical grain-oriented electrical steel sheets, the angle formed by the <001> direction of the crystal and the rolling direction is controlled so as to be within a range of about 5 °.
[0004]
　The deviation between the actual crystal orientation of the directional electromagnetic steel plate and the ideal {110} <001> orientation is the deviation angle α around the rolling surface normal direction Z, the deviation angle β around the rolling perpendicular direction C, and the rolling direction. It can be represented by the three components of the deviation angle γ around L.
[0005]
　FIG. 1 is a schematic diagram illustrating a shift angle α, a shift angle β, and a shift angle γ. As shown in FIG. 1, the deviation angle α is an angle formed by the <001> direction of the crystal projected on the rolled surface and the rolling direction L when viewed from the rolling surface normal direction Z. The deviation angle β is the angle formed by the <001> direction of the crystal projected on the L cross section (cross section with the rolling perpendicular direction as the normal) and the rolling direction L when viewed from the rolling perpendicular direction C (plate width direction). is there. The deviation angle γ is an angle formed by the <110> direction of the crystal projected on the C cross section (cross section with the rolling direction as the normal) and the rolling surface normal direction Z when viewed from the rolling direction L.
[0006]
　Of the deviation angles α, β, and γ, the deviation angle β is known to affect magnetostriction. Magnetostriction is a phenomenon in which a magnetic material changes its shape when a magnetic field is applied. In grain-oriented electrical steel sheets used for transformers of transformers, magnetostriction causes vibration and noise, so that magnetostriction is required to be small.
[0007]
　For example, Patent Documents 1 to 3 disclose that the shift angle β is controlled. Further, it is disclosed in Patent Documents 4 and 5 that the deviation angle α is controlled in addition to the deviation angle β. Further, Patent Document 6 discloses a technique for improving the iron loss characteristics by classifying the degree of integration of crystal orientations in more detail by using the deviation angle α, the deviation angle β, and the deviation angle γ as indexes.
[0008]
　Further, for example, Patent Documents 7 to 9 disclose that not only the magnitude and the average value of the absolute values ​​of the deviation angles α, β, and γ are controlled, but also the fluctuation (deviation) is included in the control. Further, Patent Documents 10 to 12 disclose that Nb, V and the like are added to the grain-oriented electrical steel sheet.
[0009]
　Further, the grain-oriented electrical steel sheet is required to have excellent magnetic flux density in addition to magnetostriction. So far, a method of controlling the growth of crystal grains in secondary recrystallization to obtain a steel sheet having a high magnetic flux density has been proposed. For example, in Patent Documents 13 and 14, a method of advancing secondary recrystallization while giving a temperature gradient to a steel sheet in the tip region of secondary recrystallized grains that are eroding the primary recrystallized grains in a finish annealing step. Is disclosed.
[0010]
　When secondary recrystallized grains are grown using a temperature gradient, the grain growth is stable, but the crystal grains may become excessively large. If the crystal grains become excessively large, the effect of improving the magnetic flux density may be hindered by the influence of the curvature of the coil. For example, in Patent Document 15, when the secondary recrystallization is allowed to proceed while giving a temperature gradient, a process of suppressing the free growth of the secondary recrystallization generated at the initial stage of the secondary recrystallization (for example, in the width direction of the steel sheet). The process of applying mechanical strain to the end of the surface) is disclosed.
Prior art literature
Patent documents
[0011]
Patent Document 1: Japanese Patent Application Laid-Open No. 2001-294996
Patent Document 2: Japanese Patent Application Laid-Open No. 2005-240102
Patent Document 3: Japanese Patent Application Laid-Open No. 2015-206114
Patent Document 4: Japanese Patent Application Laid-Open No. 2004-060026 JP
Patent Document 5: WO 2016/056501
Patent Document 6: Japanese Patent 2007-314826 JP
Patent Document 7: Japanese Patent 2001-192785 JP
Patent Document 8: Japanese Patent 2005-240079 JP
Patent Document 9: Japanese Patent 2012-052229 JP
Patent Document 10: Japanese Sho 52-024116 Patent Publication
JP 11: Japanese Patent Laid-Open 02-200732 discloses
Patent Document 12: Japanese Patent No. 4962516 JP
Patent Document 13: Japanese Sho 57-002839 Patent Publication
JP 14: Japanese Sho 61-190017 Patent Publication
JP 15: Japanese Patent Laid-Open 02-258923 discloses
Outline of the invention
Problems to be solved by the invention
[0012]
　As a result of studies by the present inventors, it cannot be said that the conventional techniques disclosed in Patent Documents 1 to 9 are particularly sufficient in reducing magnetostriction, although they control the crystal orientation.
[0013]
　Further, since the conventional techniques disclosed in Patent Documents 10 to 12 merely contain Nb and V, it cannot be said that the reduction of magnetostriction is sufficient. Further, the conventional techniques disclosed in Patent Documents 13 to 15 not only have a problem from the viewpoint of productivity, but also cannot be said to sufficiently reduce magnetostriction.
[0014]
　An object of the present invention is to provide a grain-oriented electrical steel sheet having improved magnetostriction in view of the current situation in which reduction of magnetostriction is required for grain-oriented electrical steel sheets. In particular, it is an object of the present invention to provide a grain-oriented electrical steel sheet in which both magnetostriction and iron loss in a medium magnetic field region (magnetic field of about 1.7 T) are improved.
Means to solve problems
[0015]
　The gist of the present invention is as follows.
[0016]
(1) The directional electromagnetic steel plate according to one aspect of the present invention has Si: 2.0 to 7.0%, Nb: 0 to 0.030%, V: 0 to 0.030%, Mo in mass%. : 0 to 0.030%, Ta: 0 to 0.030%, W: 0 to 0.030%, C: 0 to 0.0050%, Mn: 0 to 1.0%, S: 0 to 0. 0150%, Se: 0 to 0.0150%, Al: 0 to 0.0650%, N: 0 to 0.0050%, Cu: 0 to 0.40%, Bi: 0 to 0.010%, B: 0 to 0.080%, P: 0 to 0.50%, Ti: 0 to 0.0150%, Sn: 0 to 0.10%, Sb: 0 to 0.10%, Cr: 0 to 0.30 %, Ni: 0 to 1.0%, the balance has a chemical composition consisting of Fe and impurities, and the directional electromagnetic steel plate has a texture oriented in the Goss direction. The deviation angle from the ideal Goss direction as the axis is defined as α, the deviation angle from the ideal Goss direction with the rolling perpendicular direction C as the rotation axis is defined as β, and the deviation angle from the ideal Goss direction with the rolling direction L as the rotation axis is defined as β. The deviation angle of is defined as γ, and the deviation angle of the crystal orientation measured at two measurement points adjacent to each other on the plate surface and having an interval of 1 mm is (α 1　β 1　γ 1 ) and (α 2　β 2　γ 2). ), And the boundary condition BA is [(α 2- α 1 ) 2 + (β 2 ). -Β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 ≥ 0.5 °, and the boundary condition BB is defined as [(α 2- α 1 ) 2 + (β 2- β 1 ) 2 + (Γ 2- γ 1 ) 2 ] When 1/2 ≧ 2.0 ° is defined, there is a grain boundary that satisfies the boundary condition BA and does not satisfy the boundary condition BB.
(2) In the oriented electrical steel sheet according to (1), the average crystal grain size in the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as the rolling direction L obtained based on the boundary conditions BB the average crystal grain size of the particle diameter RB L when defining the particle size RA LParticle size RB and L and is, 1.15 ≦ RB L ÷ RA L may satisfy.
(3) In the oriented electrical steel sheet according to (1) or (2), the average crystal grain size of the perpendicular to the rolling direction C determined based on the boundary conditions BA particle size RA C is defined as, based on the boundary conditions BB the average crystal grain size of the perpendicular to the rolling direction C obtaining Te particle diameter RB C when defining the particle size RA C and a particle size RB C is a, 1.15 ≦ RB C ÷ RA C may satisfy.
(4) In the oriented electrical steel sheet according to any one of the above (1) to (3), the average crystal grain size in the rolling direction L particle size RA obtained based on the boundary conditions BA L is defined as the boundary the average crystal grain size of the perpendicular to the rolling direction C particle size RA determined based on the condition BA C when defining the particle size RA L and a particle size RA C and a, 1.15 ≦ RA C ÷ RA L be met Good.
(5) In the directional electromagnetic steel sheet according to any one of (1) to (4) above, the average crystal grain size in the rolling direction L obtained based on the boundary condition BB is defined as the particle size RB L, and the boundary is defined. When the average crystal grain size in the rolling perpendicular direction C obtained based on the condition BB is defined as the particle size RB C , even if the particle size RB L and the particle size RB C satisfy 1.50 ≦ RB C ÷ RB L. Good.
(6) In the oriented electrical steel sheet according to any one of the above (1) to (5), the average crystal grain size in the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as the boundary the average grain size in the rolling direction L particle diameter RB determined based on the conditions BB L is defined as the average crystal grain size of the perpendicular to the rolling direction C determined based on the boundary conditions BA particle size RA C is defined as the boundary condition the average crystal grain size of the perpendicular to the rolling direction C particle size RB determined based on BB C when defining the particle size RA L and a particle size RA C and particle size RB L and a particle size RB C and a, (RB C × RA L ) ÷ (RB L × RA C ) <1.0 may satisfy.
(7) In the directional electromagnetic steel plate according to any one of (1) to (6) above, the deviation angle of the crystal orientation measured at the measurement point on the plate surface is expressed as (α β γ), and each measurement is performed. When the deviation angle at a point is defined as θ = [α 2 + β 2 + γ 2 ] 1/2 , the standard deviation σ (θ) of the absolute value of the deviation angle θ is 0 ° or more and 3.0 ° or less. May be good.
(8) In the directional electromagnetic steel plate according to any one of (1) to (7) above, when the boundary condition BC is defined as | α 2- α 1 | ≧ 0.5 °, the boundary condition BC is defined as | α 2- α 1 | ≧ 0.5 °. There may be grain boundaries that satisfy and do not satisfy the boundary condition BB.
(9) In the directional electromagnetic steel sheet according to any one of (1) to (8) above, the average crystal grain size in the rolling direction L obtained based on the boundary condition BC is defined as the particle size RC L, and the boundary is defined. When the average crystal grain size in the rolling direction L obtained based on the condition BB is defined as the particle size RB L , the particle size RC L and the particle size RB L may satisfy 1.10 ≦ RB L ÷ RC L.
(10) In the directional electromagnetic steel sheet according to any one of (1) to (9) above, the average crystal grain size in the rolling perpendicular direction C obtained based on the boundary condition BC is defined as the particle size RC C. the average crystal grain size of the perpendicular to the rolling direction C particle size RB obtained based on boundary conditions BB C when defining the particle size RC C and particle size RB C and is, 1.10 ≦ RB C ÷ RC C meets May be good.
(11) In the directional electromagnetic steel sheet according to any one of (1) to (10) above, the average crystal grain size in the rolling direction L obtained based on the boundary condition BC is defined as the particle size RC L, and the boundary is defined. When the average crystal grain size in the rolling perpendicular direction C obtained based on the condition BC is defined as the particle size RC C , even if the particle size RC L and the particle size RC C satisfy 1.15 ≤ RC C ÷ RC L. Good.
(12) In the directional electromagnetic steel sheet according to any one of (1) to (11) above, the average crystal grain size in the rolling direction L obtained based on the boundary condition BC is defined as the particle size RC L, and the boundary is defined. The average crystal grain size in the rolling direction L obtained based on the condition BB is defined as the particle size RB L, and the average crystal grain size in the rolling perpendicular direction C obtained based on the boundary condition BC is defined as the particle size RC C. the average crystal grain size of the perpendicular to the rolling direction C particle size RB determined based on BB C when defining the particle size RC L and a particle size RC C and particle size RB L and a particle size RB C and a, (RB C × RC L ) ÷ (RB L × RC C ) <1.0 may be satisfied.
(13) In the grain-oriented electrical steel sheet according to any one of (1) to (12) above, the standard deviation σ (| α |) of the absolute value of the deviation angle α is 0 ° or more and 3.50 ° or less. It may be.
(14) In the grain-oriented electrical steel sheet according to any one of (1) to (13) above, at least one selected from the group consisting of Nb, V, Mo, Ta, and W is used as the chemical composition. A total of 0.0030 to 0.030% by mass may be contained.
(15) In the grain-oriented electrical steel sheet according to any one of (1) to (14) above, the magnetic domain is subdivided by at least one of applying local microstrain or forming a local groove. May be good.
(16) In the grain-oriented electrical steel sheet according to any one of (1) to (15) above, the intermediate layer arranged in contact with the grain-oriented electrical steel sheet and the insulation arranged in contact with the intermediate layer. It may have a coating.
(17) In the grain-oriented electrical steel sheet according to any one of (1) to (16) above, the intermediate layer may be a forsterite film having an average thickness of 1 to 3 μm.
(18) In the grain-oriented electrical steel sheet according to any one of (1) to (17) above, the intermediate layer may be an oxide film having an average thickness of 2 to 500 nm.
Effect of the invention
[0017]
　According to the above aspect of the present invention, a grain-oriented electrical steel sheet having improved both magnetostriction and iron loss in a medium magnetic field region (particularly a magnetic field of about 1.7 T) can be obtained.
A brief description of the drawing
[0018]
FIG. 1 is a schematic diagram illustrating a shift angle α, a shift angle β, and a shift angle γ.
FIG. 2 is a schematic cross-sectional view of a grain-oriented electrical steel sheet according to an embodiment of the present invention.
FIG. 3 is a flow chart of a method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention.
Mode for carrying out the invention
[0019]
　A preferred embodiment of the present invention will be described in detail. However, the present invention is not limited to the configuration disclosed in the present embodiment, and various modifications can be made without departing from the spirit of the present invention. In addition, the lower limit value and the upper limit value are included in the numerical limitation range described below. Numerical values ​​that indicate "greater than" or "less than" are not included in the numerical range. Further, "%" regarding the chemical composition means "mass%" unless otherwise specified.
[0020]
　If the crystal orientation approaches the ideal {110} <001> orientation (Goss orientation), for example, if the standard deviation of the deviation angle of the crystal orientation approaches zero, the iron loss and magnetostriction are reduced. There is a limit to what you can do. The present inventors investigated the cause of this. The correlation between the crystal orientation and the magnetic flux density should be high theoretically. Therefore, the magnetic flux density B in the rolling direction 8 and noted the deviation of the correlation between the iron loss and magnetostriction.
[0021]
　As a result of the examination, the strength of the magnetic field at the time of magnetization is generally the magnetic field region near 1.7T, which is the strength of the magnetic field at the time of measuring the magnetic characteristics (hereinafter, simply referred to as "medium magnetic field region"). in there), the magnetic flux density B 8 correlation between the iron loss was found to be relatively high.
[0022]
　As a result of analyzing the relationship between the magnetic characteristics and the deviation angle of the crystal orientation of the grain-oriented electrical steel sheet in this magnetic field region, the magnetic flux density B 8 in the rolling direction strongly correlates with the deviation angle α and the deviation angle β, which is more detailed. Was confirmed to strongly correlate with (α 2 + β 2 ) 1/2 . That is, it was confirmed that it is important to reduce both the deviation angle α and the deviation angle β as the crystal orientation. This finding supports a known technique for controlling the shift angle α and the shift angle β. That is, by controlling the crystal orientation in consideration of the deviation angle α and the deviation angle β, the magnetic flux density B 8 can be increased and the iron loss value in the medium magnetic field region can be decreased.
[0023]
　However, the present inventors have found that in some of the material, the magnetic flux density B 8 was found that in some cases the correlation between the magnetostriction becomes weak. When this situation was investigated, its behavior was evaluated by the "difference between the minimum and maximum values ​​of magnetostriction" (hereinafter referred to as "λpp@1.7T"), which is the amount of magnetostriction at 1.7T. I found out that I can do it. Then, if this behavior can be optimally controlled, it is possible to further improve the magnetostriction in the medium magnetic field region.
[0024]
　Based on the measurement results of the distribution of the deviation angles α, β, and γ in the grain-oriented electrical steel sheet, the present inventors have diligently studied the geometric factors for preferably controlling λpp@1.7T. As a result, "spatial three-dimensional orientation difference" (angle φ: φ = [(α 2- α 1 ) 2 + (β ), which is a value calculated from the deviation angles α, β, and γ of the directional electromagnetic steel plate. We recognized that it is important to control the crystal orientation for 2- β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 ).
[0025]
　The present inventors have studied that the crystal is not grown while maintaining the crystal orientation at the stage of growth of the secondary recrystallized grains, but is grown with the orientation change. As a result, during the growth of the secondary recrystallized grains, a large number of local and small tilt angle changes (grain boundaries with a small angle φ value) that were not conventionally recognized as grain boundaries are generated, and one It was found that the state in which the secondary recrystallized grains are divided into small regions having slightly different crystal orientations is advantageous for improving magnetostriction and iron loss in the medium magnetic field region.
[0026]
　Further, in order to control the above-mentioned orientation change, it is important to consider a factor that facilitates the orientation change itself and a factor that makes the orientation change continuously occur in one crystal grain. I found out. Then, in order to facilitate the occurrence of the orientation change itself, it is effective to start the secondary recrystallization from a lower temperature. For example, it was confirmed that the primary recrystallization particle size can be controlled and elements such as Nb can be utilized. .. Furthermore, by using a conventionally used inhibitor such as AlN in an appropriate temperature and atmosphere, it is possible to continuously generate an orientation change up to a high temperature region in one crystal grain in the secondary recrystallization. I confirmed that I could do it.
[0027]
[First Embodiment] In the
　grain-oriented electrical steel sheet according to the first embodiment of the present invention, the inside of the secondary recrystallized grain is divided into a plurality of regions by grain boundaries having a small angle φ value. That is, in the directional electromagnetic steel plate according to the present embodiment, in addition to the grain boundaries having a relatively large angle difference corresponding to the grain boundaries of the secondary recrystallized grains, the inside of the secondary recrystallized grains is locally divided. It has a small tilt angle grain boundary (grain boundary with a small angle φ value).
[0028]
　Specifically, the directional electromagnetic steel plate according to the present embodiment has Si: 2.0 to 7.0%, Nb: 0 to 0.030%, V: 0 to 0.030%, Mo in mass%. : 0 to 0.030%, Ta: 0 to 0.030%, W: 0 to 0.030%, C: 0 to 0.0050%, Mn: 0 to 1.0%, S: 0 to 0. 0150%, Se: 0 to 0.0150%, Al: 0 to 0.0650%, N: 0 to 0.0050%, Cu: 0 to 0.40%, Bi: 0 to 0.010%, B: 0 to 0.080%, P: 0 to 0.50%, Ti: 0 to 0.0150%, Sn: 0 to 0.10%, Sb: 0 to 0.10%, Cr: 0 to 0.30 A directional electromagnetic steel plate containing%, Ni: 0 to 1.0%, having a chemical composition in which the balance is composed of Fe and impurities, and having a texture oriented in the Goss direction, in the
　rolling surface normal direction. The deviation angle from the ideal Goss direction with Z as the rotation axis is defined as α, the deviation angle from the ideal Goss direction with the rolling perpendicular direction (plate width direction) C as the rotation axis is defined as β, and the rolling direction L is defined as β. The deviation angle from the ideal Goss orientation as the rotation axis is defined as γ, and the deviation angle of
　the crystal orientation measured at two measurement points adjacent to each other on the plate surface and having an interval of 1 mm is (α 1　β 1).　It is expressed as γ 1 ) and (α 2　β 2　γ 2 ), and the boundary condition BA is [(α 2- α 1 ). 2 + (beta 2 -beta 1 ) 2 + (gamma 2 -gamma 1 ) 2 ] 1/2 is defined as ≧ 0.5 °, the boundary condition BB [(alpha 2 -.alpha. 1 ) 2 + (beta 2 - When defined as β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 ≧ 2.0 °, the
　directional electromagnetic steel plate according to the present embodiment has a grain boundary (secondary) that satisfies the above boundary condition BB. In addition to the grain boundaries corresponding to the recrystallized grain boundaries, the grain boundaries satisfy the boundary condition BA and do not satisfy the boundary condition BB (grain boundaries that divide the secondary recrystallized grains).
[0029]
　The grain boundaries satisfying the boundary condition BB substantially correspond to the secondary recrystallized grain boundaries observed when the conventional grain-oriented electrical steel sheet is macro-etched. The grain-oriented electrical steel sheet according to the present embodiment has grain boundaries that satisfy the boundary condition BB and do not satisfy the boundary condition BB at a relatively high frequency. The grain boundaries that satisfy the boundary condition BA and do not satisfy the boundary condition BB correspond to the local and small tilt angle grain boundaries that divide the secondary recrystallized grains. That is, in the present embodiment, the secondary recrystallized grains are in a state of being finely divided into small regions having slightly different crystal orientations.
[0030]
　Conventional grain-oriented electrical steel sheets may have secondary recrystallized grain boundaries that satisfy the boundary condition BB. Further, in the conventional grain-oriented electrical steel sheet, the crystal orientation may be gently displaced within the grains of the secondary recrystallized grains. However, in the conventional directional electromagnetic steel plate, the crystal orientation tends to be continuously displaced in the secondary recrystallized grains, so that the displacement of the crystal orientation existing in the conventional directional electromagnetic steel plate is the above-mentioned boundary condition BA. It is difficult to be satisfied.
[0031]
　For example, in a conventional directional electromagnetic steel plate, the displacement of the crystal orientation may be identified in the long range region in the secondary recrystallized grains, but the displacement of the crystal orientation is small in the short range region in the secondary recrystallized grains. Therefore, it is difficult to identify (it is difficult to satisfy the boundary condition BA). On the other hand, in the grain-oriented electrical steel sheet according to the present embodiment, the crystal orientation is locally displaced in a short range region and can be identified as a grain boundary. Specifically, between two measurement points adjacent to each other and having an interval of 1 mm in the secondary recrystallized grain, [(α 2- α 1 ) 2 + (β 2- β 1 ) 2 + (γ 2 ) -Γ 1 ) 2 ] Displacement in which the value of 1/2 is 0.5 ° or more exists at a relatively high frequency.
[0032]
　In the grain-oriented electrical steel sheet according to the present embodiment, by precisely controlling the manufacturing conditions as described later, the grain boundaries (grains that divide the secondary recrystallized grains) that satisfy the boundary condition BA and do not satisfy the boundary condition BB are satisfied. The world) is intentionally created. In the grain-oriented electrical steel sheet according to the present embodiment, the secondary recrystallized grains are in a state of being divided by grain boundaries having a small angle φ value, and both magnetostriction and iron loss in the medium magnetic field region are improved.
[0033]
　Hereinafter, the grain-oriented electrical steel sheet according to the present embodiment will be described in detail.
[0034]
1. 1. Crystal Orientation
　First, the description of the crystal orientation in the present embodiment will be described.
　In the present embodiment, two {110} <001> orientations of "actual crystal {110} <001> orientation" and "ideal {110} <001> orientation" are distinguished. The reason for this is that in the present embodiment, it is necessary to distinguish between the {110} <001> orientation when displaying the crystal orientation of the practical steel sheet and the {110} <001> orientation as the academic crystal orientation. Because.
[0035]
　Generally, in the measurement of the crystal orientation of a recrystallized practical steel sheet, the crystal orientation is defined without strictly distinguishing the angle difference of about ± 2.5 °. In the case of conventional grain-oriented electrical steel sheets, the angular range of about ± 2.5 ° centered on the geometrically exact {110} <001> orientation is defined as the "{110} <001> orientation". .. However, in this embodiment, it is necessary to clearly distinguish the angle difference of ± 2.5 ° or less.
[0036]
　Therefore, in the present embodiment, when the orientation of the grain-oriented electrical steel sheet is meant in a practical sense, it is simply described as "{110} <001> orientation (Goss orientation)" as in the conventional case. On the other hand, when the {110} <001> orientation as a geometrically exact crystal orientation is meant, in order to avoid confusion with the {110} <001> orientation used in conventional publicly known documents and the like, " "Ideal {110} <001> direction (ideal Goss direction)".
[0037]
　Therefore, in the present embodiment, for example, there is a description that "the {110} <001> orientation of the grain-oriented electrical steel sheet according to the present embodiment deviates by 2 ° from the ideal {110} <001> orientation." Sometimes.
[0038]
　Further, in the present embodiment, the following five angles α, β, γ, θ, and φ related to the crystal orientation observed in the directional electromagnetic steel plate are used.
[0039]
　Deviation angle α: The deviation angle of the crystal orientation observed on the grain-oriented electrical steel sheet from the ideal {110} <001> orientation around the rolling surface normal direction Z.
　Deviation angle β: The deviation angle of the crystal orientation observed on the grain-oriented electrical steel sheet from the ideal {110} <001> orientation around the rolling perpendicular direction C.
　Deviation angle γ: The deviation angle of the crystal orientation observed on the grain-oriented electrical steel sheet from the ideal {110} <001> orientation around the rolling direction L.
　A schematic diagram of the deviation angle α, the deviation angle β, and the deviation angle γ is shown in FIG.
[0040]
　Deviation angle θ: An angle of deviation from the ideal {110} <001> orientation obtained by θ = [α 2 + β 2 + γ 2 ] 1/2 using the above deviation angles α, β, and γ .
[0041]
　Angle φ: The deviation angles of the crystal orientations measured at two measurement points adjacent to each other on the rolled surface of the directional electromagnetic steel plate and having an interval of 1 mm are (α 1 , β 1 , γ 1 ) and (α 2 ) , respectively. , Β 2 , γ 2 ), the angle obtained by φ = [(α 2- α 1 ) 2 + (β 2- β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 .
　This angle φ may be described as “spatial three-dimensional directional difference”.
[0042]
2. 2. Crystal grain boundaries of directional electromagnetic steel sheets The directional electromagnetic steel sheets according to the
　present embodiment are conventionally generated in order to control a spatial three-dimensional orientation difference (angle φ), particularly during the growth of secondary recrystallized grains. Then, we use a local change in crystal orientation that was not recognized as a grain boundary. In the following description, the above-mentioned orientation change that occurs so as to divide one secondary recrystallized grain into small regions having slightly different crystal orientations may be described as "switching".
　Further, the crystal grain boundaries that divide the secondary recrystallized grains (grain boundaries that satisfy the boundary condition BA and do not satisfy the boundary condition BB) are distinguished as "subgrain boundaries", and the grain boundaries including the subgrain boundaries are distinguished as boundaries. The resulting crystal grains may be referred to as "sub-crystal grains".
[0043]
　Further, regarding iron loss (W 17/50 ) and magnetostriction (λpp@1.7T) in a medium magnetic field, which are characteristics related to the present embodiment , in the following description, these are simply referred to as "iron loss" and respectively. Sometimes referred to as "magnetostriction".
[0044]
　It is considered that the above switching occurs in the process in which the change in crystal orientation is about 1 ° (less than 2 °) and the growth of the secondary recrystallized grains continues. Details will be described later in relation to the production method, but it is important to grow the secondary recrystallized grains in a situation where switching is likely to occur. For example, it is important to start the secondary recrystallization at a relatively low temperature by controlling the primary recrystallization particle size and to continue the secondary recrystallization to a high temperature by controlling the type and amount of the inhibitor.
[0045]
　The reason why the control of the angle φ affects the magnetic characteristics is not always clear, but it is presumed as follows.
[0046]
　Generally, the magnetization behavior is caused by the movement of the 180 ° magnetic domain and the rotation of the magnetization from the direction in which the magnetization is easy. It is considered that this magnetic domain movement and magnetization rotation are affected by the continuity of the magnetic domain with the adjacent crystal grains or the continuity of the magnetization direction, and the orientation difference with the adjacent grains may be linked to the magnitude of the disturbance of the magnetization behavior. .. In the switching controlled in the present embodiment, switching (local orientation change) occurs frequently in one secondary recrystallized grain, so that the relative orientation difference with the adjacent grain is reduced and the directionality is directional. It is considered that it works to enhance the continuity of the crystal orientation in the entire electromagnetic steel sheet.
[0047]
　In this embodiment, two types of boundary conditions are defined for changes in crystal orientation including switching. In this embodiment, the definition of "grain boundary" based on these boundary conditions is important.
[0048]
　Currently, the crystal orientation of practically manufactured grain-oriented electrical steel sheets is controlled so that the deviation angle between the rolling direction and the <001> direction is approximately 5 ° or less. This control is the same for the grain-oriented electrical steel sheet according to the present embodiment. Therefore, when defining the "grain boundaries" of grain-oriented electrical steel sheets, the "boundary where the orientation difference between adjacent regions is 15 ° or more", which is the general definition of grain boundaries (large tilt angle grain boundaries), is applied. Can't. For example, in a conventional grain-oriented electrical steel sheet, grain boundaries are revealed by macro-etching of the steel sheet surface, but in this case, the crystal orientation difference between the two side regions of the grain boundaries is usually about 2 to 3 °.
[0049]
　In this embodiment, as will be described later, it is necessary to strictly define the boundary between crystals. Therefore, as a method for specifying grain boundaries, a visual-based method such as macro etching is not adopted.
[0050]
　In the present embodiment, in order to specify the grain boundaries, measurement lines including at least 500 measurement points are set on the rolled surface at 1 mm intervals, and the crystal orientation is measured. For example, the crystal orientation may be measured by an X-ray diffraction method (Laue method). The Laue method is a method of irradiating a steel sheet with an X-ray beam and analyzing the transmitted or reflected diffraction spots. By analyzing the diffraction spots, the crystal orientation of the place where the X-ray beam is irradiated can be identified. By analyzing the diffraction spots at a plurality of locations by changing the irradiation position, the crystal orientation distribution at each irradiation position can be measured. The Laue method is a method suitable for measuring the crystal orientation of a metal structure having coarse crystal grains.
[0051]
　The number of measurement points for the crystal orientation may be at least 500, but it is preferable to appropriately increase the number of measurement points according to the size of the secondary recrystallized grains. For example, when the number of secondary recrystallized grains contained in the measurement line is less than 10 when the measurement point for measuring the crystal orientation is 500 points, 10 or more secondary recrystallized grains are included in the measurement line. It is preferable to extend the above measurement line by increasing the number of measurement points at 1 mm intervals.
[0052]
　The crystal orientation is measured at 1 mm intervals on the rolled surface, and then the above-mentioned deviation angle α, deviation angle β, and deviation angle γ are specified for each measurement point. Based on the deviation angle at each specified measurement point, it is determined whether or not there is a grain boundary between two adjacent measurement points. Specifically, it is determined whether or not the two adjacent measurement points satisfy the above-mentioned boundary condition BA and / or boundary condition BB.
[0053]
　Specifically, when the deviation angles of the crystal orientations measured at two adjacent measurement points are expressed as (α 1 , β 1 , γ 1 ) and (α 2 , β 2 , γ 2 ), respectively, the boundary condition BA the [(alpha 2 -.alpha. 1 ) 2 + (beta 2 -beta 1 ) 2 + (gamma 2 -gamma 1 ) 2 ] 1/2 is defined as ≧ 0.5 °, the boundary condition BB [(alpha 2 - α 1 ) 2 + (β 2- β 1 ) 2+ (Γ 2- γ 1 ) 2 ] 1/2 ≧ 2.0 °. It is determined whether or not there is a grain boundary satisfying the boundary condition BA and / or the boundary condition BB between two adjacent measurement points.
[0054]
　The grain boundary satisfying the boundary condition BB has a spatial three-dimensional orientation difference (angle φ) between two points sandwiching the grain boundary of 2.0 ° or more, and this grain boundary was recognized by macro etching. It can be said that it is almost the same as the grain boundary of the conventional secondary recrystallized grains.
[0055]
　Apart from the grain boundaries that satisfy the above boundary condition BB, the directional electromagnetic steel sheet according to the present embodiment has grain boundaries that are strongly related to "switching", specifically, the boundary condition BA that satisfies the boundary condition BA. Grain boundaries that do not satisfy BB are present at a relatively high frequency. The grain boundaries defined in this way correspond to grain boundaries that divide one secondary recrystallized grain into small regions with slightly different crystal orientations.
[0056]
　The above two grain boundaries can also be determined using different measurement data. However, considering the time and effort of measurement and the deviation from the actual situation due to the difference in data, the deviation angle of the crystal orientation obtained from the same measurement line (at least 500 measurement points at 1 mm intervals on the rolled surface) is used. Therefore, it is preferable to obtain the above two grain boundaries.
[0057]
　Since the directional electromagnetic steel plate according to the present embodiment has a grain boundary satisfying the boundary condition BB and a grain boundary satisfying the boundary condition BA and not satisfying the boundary condition BB at a relatively high frequency, it is secondary. The recrystallized grains are divided into small regions having slightly different crystal orientations, and as a result, both magnetostriction and iron loss in the medium magnetic field region are improved.
[0058]
　In this embodiment, it is sufficient that the steel sheet has a "grain boundary that satisfies the boundary condition BA and does not satisfy the boundary condition BB". However, substantially, in order to improve magnetostriction and iron loss, it is preferable that grain boundaries satisfying the boundary condition BA and not satisfying the boundary condition BB exist at a relatively high frequency.
[0059]
　Specifically, when the crystal orientation is measured at at least 500 measurement points at 1 mm intervals on the rolled surface, the deviation angle is specified at each measurement point, and the boundary condition is determined at two adjacent measurement points. The "grain boundaries satisfying the boundary condition BA" may be present at a ratio of 1.15 times or more than the "grain boundaries satisfying the boundary condition BB". That is, when the boundary condition is determined as described above, the value obtained by dividing the "number of boundaries satisfying the boundary condition BA" by the "number of boundaries satisfying the boundary condition BB" may be 1.15 or more. In the present embodiment, when the above value is 1.15 or more, it is determined that the grain grain boundary satisfying the boundary condition BA and not satisfying the boundary condition BB exists in the grain-oriented electrical steel sheet.
[0060]
　The upper limit of the value obtained by dividing the "number of boundaries satisfying the boundary condition BA" by the "number of boundaries satisfying the boundary condition BB" is not particularly limited. For example, this value may be 80 or less, 40 or less, and 30 or less.
[0061]
[Second Embodiment]
　Subsequently, the grain-oriented electrical steel sheet according to the second embodiment of the present invention will be described below. Further, in each of the embodiments described below, the differences from the first embodiment will be mainly described, and the other features will be the same as those of the first embodiment, and duplicate description will be omitted.
[0062]
　In the grain-oriented electrical steel sheet according to the second embodiment of the present invention, the grain size of the subcrystal grains in the rolling direction is smaller than the grain size of the secondary recrystallized grains in the rolling direction. That is, the grain-oriented electrical steel sheet according to the present embodiment has subcrystal grains and secondary recrystallized grains whose particle size is controlled with respect to the rolling direction.
[0063]
　Specifically, the grain-oriented electrical steel sheet according to the present embodiment, the average crystal grain size in the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as the rolling direction L obtained based on the boundary conditions BB the average crystal grain size of the particle diameter RB L when defined as,
　particle size RA L and a particle size RB L and a, 1.15 ≦ RB L ÷ RA L meet. Also, RB L ÷ RA L is preferably ≦ 80.
[0064]
　This provision describes the above-mentioned "switching" situation with respect to the rolling direction. That is, among the secondary recrystallized grains having a boundary having an angle φ of 2 ° or more as a crystal grain boundary, there is a crystal grain containing at least one boundary having an angle φ of 0.5 ° or more and less than 2 °. , Means that it exists at a reasonable frequency with respect to the rolling direction. In the present embodiment, the status of this switch, the rolling direction of the grain size RA L and particle size RB L defines evaluated by.
[0065]
　Particle size RB L for small, or the particle size RB L is larger switches less particle size RA L because of the large, RB L / RA L If value is less than 1.15, the switching frequency is not sufficient , Magnetostriction may not be sufficiently improved. RB L / RA L value is preferably 1.20 or more, more preferably 1.30 or more, more preferably 1.50 or more, more preferably 2.0 or more, more preferably 3.0 or more, more preferably It is 5.0 or more.
[0066]
　RB L / RA L is not particularly limited on the upper limit of the value. High RB occurrence frequency switching L / RA L The larger the value, because the continuity of the crystal orientation of the whole grain-oriented electromagnetic steel sheet is increased, preferred for improvement of the magnetostriction. On the other hand, since switching is also a residual lattice defect in the crystal grains, there is a concern that if the frequency of occurrence is too high, the effect of improving iron loss may be particularly reduced. Therefore, RB L / RA L 80 may be mentioned as a practical maximum value of values. Particularly if necessary considerations for iron loss, RB L / RA L as the maximum of the values, preferably 40, more preferably include 30.
[0067]
　Incidentally, if no switching at all occurred, since the crystal grain boundary that divides the inside of the secondary recrystallized grains (grain boundaries is not satisfied satisfied and boundary conditions BB boundary conditions BA) is not present, the particle size RA L and particle size RB L and the same size, RB L / RA L value is 1.0.
[0068]
　Regarding the grain-oriented electrical steel sheet according to the present embodiment, the boundaries between two measurement points adjacent to each other on the rolled surface and having an interval of 1 mm are classified into cases A to C in Table 1. The above particle diameter RB L is determined based on the grain boundaries satisfying the case A of Table 1, the particle size RA L is obtained based on the grain boundaries satisfying the case A and / or case B in Table 1. For example, the deviation angle of the crystal orientation measurement line along a rolling direction, including at least 500 measurement points were measured, the average value of the segment length to be sandwiched between the grain boundaries of the case A in this measurement line particle size RB L and To do. Similarly, in the above measuring line, a line segment length of the average value held between the grain boundaries of the case A and / or case B particle size RA L and.
[0069]
[table 1]

[0070]
　RB L / RA L affects reasons for control magnetostriction and core loss value is not necessarily clear, switched one in the secondary recrystallized grains (local azimuth changes) that occurs, the adjacent grains It is considered that the relative orientation difference between the two is reduced (the change in the crystal orientation near the grain boundaries becomes gentle), and the continuity of the crystal orientation in the entire directional electromagnetic steel plate is enhanced.
[0071]
[Third Embodiment]
　Subsequently, the grain-oriented electrical steel sheet according to the third embodiment of the present invention will be described below. In the following, the differences from the above-described embodiment will be mainly described, and duplicate description will be omitted.
[0072]
　In the directional electromagnetic steel plate according to the third embodiment of the present invention, the particle size of the subcrystal grains in the direction perpendicular to the rolling direction is smaller than the particle size of the secondary recrystallized grains in the direction perpendicular to the rolling direction. That is, the grain-oriented electrical steel sheet according to the present embodiment has subcrystal grains and secondary recrystallized grains whose particle size is controlled with respect to the direction perpendicular to rolling.
[0073]
　Specifically, the grain-oriented electrical steel sheet according to the present embodiment, the average crystal grain size of the perpendicular to the rolling direction C determined based on the boundary conditions BA particle size RA C perpendicular to the rolling which is defined as, obtained based on the boundary conditions BB particle size RB the mean crystal grain size of the direction C C when defined as,
　particle size RA C and a particle size RB C is a, 1.15 ≦ RB C ÷ RA C meet. Also, RB C ÷ RA C is preferably ≦ 80.
[0074]
　This provision describes the above-mentioned "switching" situation with respect to the direction perpendicular to rolling. That is, among the secondary recrystallized grains having a boundary having an angle φ of 2 ° or more as a crystal grain boundary, there is a crystal grain containing at least one boundary having an angle φ of 0.5 ° or more and less than 2 °. , Means that it exists at a reasonable frequency with respect to the direction perpendicular to rolling. In the present embodiment, the status of this switch, the particle diameter RA of the direction perpendicular to the rolling direction C and particle size RB C defined and evaluated by.
[0075]
　Particle size RB C for the small or the particle size RB C is larger switches less particle size RA C because of the large, RB C / RA C the value is less than 1.15, the switching frequency is not sufficient , Magnetostriction may not be sufficiently improved. RB C / RA C value is preferably 1.20 or more, more preferably 1.30 or more, more preferably 1.50 or more, more preferably 2.0 or more, more preferably 3.0 or more, more preferably It is 5.0 or more.
[0076]
　RB C / RA C There is no particular limitation on the upper limit of the value. High RB occurrence frequency switching C / RA C The greater the value, because the continuity of the crystal orientation of the whole grain-oriented electromagnetic steel sheet is increased, preferred for improvement of the magnetostriction. On the other hand, since switching is also a residual lattice defect in the crystal grains, there is a concern that if the frequency of occurrence is too high, the effect of improving iron loss may be particularly reduced. Therefore, RB C / RA C 80 can be mentioned as a practical maximum value of values. Particularly if necessary considerations for iron loss, RB C / RA C as the maximum value of the values, preferably 40, more preferably include 30.
[0077]
　Incidentally, if no switching at all occurred, since the crystal grain boundary that divides the inside of the secondary recrystallized grains (grain boundaries is not satisfied satisfied and boundary conditions BB boundary conditions BA) is not present, the particle size RA C and particle size RB C and the same size, RB C / RA C value is 1.0.
[0078]
　The above particle diameter RB C is determined based on the grain boundaries satisfying the case A of Table 1, the particle size RA C is determined based on the grain boundaries satisfying the case A and / or case B in Table 1. For example, perpendicular to the rolling direction along measures the deviation angle of the crystal orientation measurement line including at least 500 measurement points, the average value of the particle diameter RB of the line segment length sandwiched between the grain boundaries of the case A in this measurement line C And. Similarly, in the above measuring line, a line segment length of the average value held between the grain boundaries of the case A and / or case B particle size RA C and.
[0079]
　RB C / RA C affects reasons for control magnetostriction and core loss value is not necessarily clear, switched one in the secondary recrystallized grains (local azimuth changes) that occurs, the adjacent grains It is considered that the relative orientation difference between the two is reduced (the change in the crystal orientation near the grain boundaries becomes gentle), and the continuity of the crystal orientation in the entire directional electromagnetic steel plate is enhanced.
[0080]
[Fourth Embodiment]
　Subsequently, the grain-oriented electrical steel sheet according to the fourth embodiment of the present invention will be described below. In the following, the differences from the above-described embodiment will be mainly described, and duplicate description will be omitted.
[0081]
　In the directional electromagnetic steel plate according to the fourth embodiment of the present invention, the particle size of the subcrystal grains in the rolling direction is smaller than the particle size of the subcrystal grains in the direction perpendicular to the rolling direction. That is, the grain-oriented electrical steel sheet according to the present embodiment has subcrystal grains whose particle size is controlled with respect to the rolling direction and the rolling perpendicular direction.
[0082]
　Specifically, the grain-oriented electrical steel sheet according to the present embodiment, the average crystal grain size in the rolling direction L obtained based on the boundary conditions BA particle size RA L perpendicular to the rolling direction is defined as, obtained based on the boundary conditions BA the average grain size of C particle size RA C when defined as,
　particle size RA L and a particle size RA C and a, 1.15 ≦ RA C ÷ RA L meet. Furthermore, RA C ÷ RA L is preferably ≦ 10.
[0083]
　In the following description, the shape of the crystal grains may be described as "(in-plane) anisotropy" or "flat (shape)". The shape of these crystal grains describes the shape when observed from the surface (rolled surface) of the steel sheet. That is, the shape of the crystal grains does not consider the size in the plate thickness direction (observed shape in the plate thickness cross section). Incidentally, in the grain-oriented electrical steel sheet, almost all the crystal grains have the same size as the sheet thickness in the plate thickness direction. That is, in the grain-oriented electrical steel sheet, the thickness of the steel sheet is often occupied by one crystal grain except for a peculiar region such as the vicinity of the crystal grain boundary.
[0084]
　RA and the C / RA L prescribed value, for the rolling direction and the direction perpendicular to the rolling direction, indicating the status of the "switching" described above. That is, it means that the frequency with which the local crystal orientation changes to the extent that it is recognized as switching differs depending on the in-plane direction of the steel sheet. In this embodiment, the status of this switch, the particle diameter RA of the two orthogonal directions in the steel sheet surface C and particle size RA L was assessed by defining.
[0085]
　RA C / RA L that value is greater than 1, the subgrains defined by switching Viewed on average, and stretched in the direction perpendicular to the rolling direction, and shown to have a flat form collapsed in the rolling direction There is. That is, it is shown that the morphology of the crystal grains defined by the subgrain boundaries has anisotropy.
[0086]
　The reason why the magnetic properties are improved by the in-plane anisotropy of the shape of the subcrystal grains is not clear, but it is considered as follows. As described above, in the magnetization behavior, "continuity" with adjacent crystal grains is important when the 180 ° magnetic domain moves or the magnetization rotates. For example, when one secondary recrystallized grain is divided into small regions by switching, if the number of these small regions is the same (the area of ​​the small regions is the same), the shape of the small regions is more than isotropic. , The more anisotropic, the larger the abundance ratio of the boundary (subgrain boundary) due to switching. That, RA C / RA L will be present frequency of switching is a local change of orientation is increased by controlling the value is considered to enhance the continuity of the crystal orientation of the whole grain-oriented electromagnetic steel sheet.
[0087]
　The anisotropy of the occurrence of such switching is some anisotropy existing in the steel plate before the secondary recrystallization: for example, the anisotropy of the shape of the primary recrystallized grain; the anisotropy of the shape of the hot-rolled plate crystal grain. Anisotropy of crystal orientation distribution of primary recrystallized grains due to It is considered to be caused by the distribution of precipitates due to fluctuations in the thermal history in the longitudinal direction; the anisotropy of the crystal particle size distribution; However, the details of the generation mechanism are unknown. However, if the steel sheet in the secondary recrystallization has a temperature gradient, it gives direct anisotropy to the growth of crystal grains (dislocation disappearance and grain boundary formation). That is, the temperature gradient in the secondary recrystallization is a very effective control condition for controlling the anisotropy defined in the present embodiment. Details will be described in detail in relation to the manufacturing method.
[0088]
　Further, although it is related to the above-mentioned process of giving anisotropy by the temperature gradient at the time of secondary recrystallization, the direction in which the subcrystal grains are stretched in the present embodiment is the direction perpendicular to rolling, which is the current general production. It is preferable to consider the method. In this case, the rolling direction of the grain size RA L is the particle size RA of the direction perpendicular to the rolling direction C becomes smaller than. The relationship between the rolling direction and the direction perpendicular to the rolling will be described in relation to the manufacturing method. The direction in which the subcrystal grains are stretched is determined not by the temperature gradient but by the frequency of occurrence of subgrain boundaries.
[0089]
　Particle size RA C due to the small or the particle size RA C is larger in particle size RA L because of the large, RA C / RA L If value is less than 1.15, the switching frequency is not sufficient, magnetostriction It may not be possible to improve sufficiently. RA C / RA L value is preferably 1.80 or more, more preferably 2.10 or more.
[0090]
　RA C / RA L is not particularly limited on the upper limit of the value. Frequency and the extending direction of the switching is limited to a specific direction, RA C / RA L The larger the value, because the continuity of the crystal orientation of the whole grain-oriented electromagnetic steel sheet is increased, preferred for improvement of the magnetostriction. On the other hand, since switching is also a residual lattice defect in the crystal grains, if the frequency of occurrence is too high, there is a concern that the effect of improving iron loss may be particularly reduced. Therefore, RA C / RA L include 10 as a practical maximum value of values. Particularly if necessary considerations for iron loss, RA C / RA L as the maximum value of the value, preferably 6, more preferably include 4.
[0091]
　Further, grain-oriented electrical steel sheet according to the present embodiment, RA and the C / RA L In addition to controlling the value, the particle size RA described above L and a particle size RB L and a, 1.20 ≦ RB L ÷ RA L It is preferable to satisfy.
[0092]
　This provision clarifies that a "switch" is occurring. For example, particle size RA C and RA L is the angle φ between two adjacent measurement points is the particle size based on the grain boundaries to be 0.5 ° or more, "switch" is not at all generated, even if all of the grain boundaries of the angle φ was at 2.0 ° or more, RA and the C / RA L is the value is satisfied. Even RA C / RA L be values satisfying, if the angle of all the grain boundaries φ is 2.0 ° or more, only been generally recognized secondary recrystallized grains are simply becomes flat shape Therefore, the above-mentioned effect of the present embodiment cannot be preferably obtained. In the present embodiment, since it is assumed that the grain boundaries satisfy the boundary condition BA and do not satisfy the boundary condition BB (grain boundaries that divide the secondary recrystallized grains), the angles φ of all the grain boundaries are 2. situation hardly occurs that is .0 ° or more but, RA above C / RA L in addition to satisfying the value, RB L / RA L preferably satisfies the value.
[0093]
　Further, in the present embodiment, RB with respect to the rolling direction L / RA L In addition to controlling the value, for the direction perpendicular to the rolling direction, the particle size mentioned above RA C and particle size RB C and is 1.20 ≦ RB C / RA C be satisfied does not become any problem, but rather preferable in view of enhancing the continuity of the crystal orientation of the whole grain-oriented electromagnetic steel sheet.
[0094]
　Further, in the grain-oriented electrical steel sheet according to the present embodiment, it is preferable that the grain sizes of the secondary recrystallized grains in the rolling direction and the direction perpendicular to the rolling are controlled.
[0095]
　Specifically, the grain-oriented electrical steel sheet according to the present embodiment, the average crystal grain size in the rolling direction L obtained based on the boundary conditions BB particle size RB L perpendicular to the rolling direction is defined as, obtained based on the boundary conditions BB When the average crystal grain size of C is defined as the
　particle size RB C , it is preferable that the particle size RB L and the particle size RB C satisfy 1.50 ≦ RB C ÷ RB L. Further, it is preferable that RB C ÷ RB L ≦ 20.
[0096]
　This provision has nothing to do with the "switching" described above and indicates that the secondary recrystallized grains are stretched in the direction perpendicular to rolling. Therefore, this feature itself is not special. However, in the present embodiment, RA C / RA L in terms of a controlled value, RB C / RB L it is preferred that the value satisfies the numerical range mentioned above.
[0097]
　In the present embodiment, in relation to the switching of the, RA subgrain C / RA L If value is controlled tends to be planar anisotropy becomes larger form of secondary recrystallized grains. From the opposite point of view, when switching the angle φ is generated as in the present embodiment, the shape of the secondary recrystallized grains is controlled to have in-plane anisotropy, so that the shape of the subcrystal grains is also changed. Tends to have in-plane anisotropy.
[0098]
　RB C / RB L value is preferably 1.80 or more, more preferably 2.00 or more, more preferably 2.50 or more. The upper limit of the RB C / RB L value is not particularly limited.
[0099]
　As a practical method of controlling the RB C / RB L value, for example, preferential heating is performed from the end of the coil width during finish annealing, and a temperature gradient in the coil width direction (coil axis direction) is applied. Examples include the process of growing secondary recrystallized grains. At this time, while maintaining the particle size of the secondary recrystallized grains in the coil circumferential direction (for example, the rolling direction) at about 50 mm, the particle size of the secondary recrystallized grains in the coil width direction (for example, the direction perpendicular to rolling) is defined as the coil width. It is also possible to control in the same way. For example, one crystal grain can occupy the entire width of a coil having a width of 1000 mm. In this case, 20 is mentioned as the upper limit value of the RB C / RB L value.
[0100]
　If the secondary recrystallization is carried out by a continuous annealing process so as to have a temperature gradient in the rolling direction instead of the rolling perpendicular direction, the maximum value of the grain size of the secondary recrystallized grains is not limited to the coil width. It is also possible to make it a larger value. Even in this case, according to the present embodiment, it is possible to obtain the above-mentioned effect of the present embodiment by appropriately dividing the crystal grains by the subgrain boundaries due to switching.

The scope of the claims
[Claim 1]
　By mass%,
　　Si: 2.0 to 7.0%,
　　Nb: 0 to 0.030%,
　　V: 0 to 0.030%,
　　Mo: 0 to 0.030%,
　　Ta: 0 to 0.030%. ,
　　W: 0 to 0.030%,
　　C: 0 to 0.0050%,
　　Mn: 0 to 1.0%,
　　S: 0 to 0.0150%,
　　Se: 0 to 0.0150%,
　　Al: 0 to 0.0650%,
　　N: 0 to 0.0050%,
　　Cu: 0 to 0.40%,
　　Bi: 0 to 0.010%,
　　B: 0 to 0.080%,
　　P: 0 to 0.50%,
　　Ti: 0 to 0.0150%,
　　Sn: 0 to 0.10%,
　　Sb: 0 to 0.10%,
　　Cr: 0 to 0.30%,
　　Ni: 0 to 1.0%,
　and the balance In
　a directional electromagnetic steel plate having a chemical composition consisting of Fe and impurities and having an texture oriented in the Goss orientation.
　The deviation angle from the ideal Goss direction with the rolling surface normal direction Z as the rotation axis is defined as α, the deviation angle from the ideal Goss direction with the
　rolling perpendicular direction C as the rotation axis is defined as β, and the
　rolling direction L is defined as β. The deviation angle from the ideal Goss orientation as the rotation axis is defined as γ, and the deviation angle of
　the crystal orientation measured at two measurement points adjacent to each other on the plate surface and having an interval of 1 mm is (α 1　β 1　γ 1 ). And (α 2　β 2　γ 2 ), and the
　boundary condition BA is [(α 2- α 1 ) 2 + (β 2- β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 ≧ 0. Defined as 5 °
　When the boundary condition BB is defined as [(α 2- α 1 ) 2 + (β 2- β 1 ) 2 + (γ 2- γ 1 ) 2 ] 1/2 ≧ 2.0 °, the
　boundary condition BA is defined as
A directional electromagnetic steel plate characterized in that there is a grain boundary that satisfies and does not satisfy the boundary condition BB .
[Claim 2]
　Wherein an average crystal grain size of the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as,
　the particle diameter RB of the average crystal grain size in the rolling direction L obtained based on the boundary conditions BB L defined as to time,
　the particle size RA L and the grain size RB L and is, 1.15 ≦ RB L ÷ RA L meet,
oriented electrical steel sheet according to claim 1, characterized in that.
[Claim 3]
　The boundary conditions the average crystal grain size of the perpendicular to the rolling direction C particle size RA obtained based on BA C is defined as,
　the direction perpendicular to the rolling direction C the average crystal grain size of the particle diameter RB of determined based on the boundary conditions BB C when defining the,
　the particle size RA C and the particle diameter RB C and is, 1.15 ≦ RB C ÷ RA C meet,
oriented electrical steel sheet according to claim 1 or claim 2, characterized in that ..
[Claim 4]
　The average crystal grain size in the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as,
　the average crystal grain size of the perpendicular to the rolling direction C obtained based on the boundary conditions BA particle size RA C and when defining,
　the particle size RA L and the grain size RA C and is, 1.15 ≦ RA C ÷ RA L meet,
that directionality according to any one of claims 1 to 3, wherein Electromagnetic steel plate.
[Claim 5]
　The average crystal grain size in the rolling direction L obtained based on the boundary conditions BB particle size RB L is defined as,
　the average crystal grain size of the perpendicular to the rolling direction C obtained based on the boundary conditions BB particle size RB C and when defining,
　the particle diameter RB L and the grain size RB C and is, 1.50 ≦ RB C ÷ RB L meet,
that directionality according to any one of claims 1 to 4, wherein Electromagnetic steel plate.
[Claim 6]
　Wherein an average crystal grain size of the rolling direction L obtained based on the boundary conditions BA particle size RA L is defined as,
　the particle diameter RB of the average crystal grain size in the rolling direction L obtained based on the boundary conditions BB L defined as and,
　the average crystal grain size of the perpendicular to the rolling direction C obtained based on the boundary conditions BA particle size RA C is defined as,
　the particle diameter of the average crystal grain size of the perpendicular to the rolling direction C obtained based on the boundary conditions BB RB C when defining the,
　the particle size RA L and the grain size RA C and the particle diameter RB L and the grain size RB C and
　is, (RB C × RA L ) ÷ (RB L × RA C ) <1
The directional electromagnetic steel sheet according to any one of claims 1 to 5, wherein the directional electromagnetic steel sheet satisfies .0 .
[Claim 7]
　When the deviation angle of the crystal orientation measured at the measurement point on the plate surface is expressed as (α β γ) and the deviation angle at each measurement point is defined as θ = [α 2 + β 2 + γ 2 ] 1/2 , the
　above The directional electromagnetic steel plate according to any one of claims 1 to 6, wherein the standard deviation σ (θ) of the absolute value of the deviation angle θ is 0 ° or more and 3.0 ° or less.
[Claim 8]
　Claim 1 is characterized in that when the boundary condition BC is defined 　as | α 2- α 1 | ≧ 0.5 °,
there is a grain boundary that satisfies the boundary condition BC and does not satisfy the boundary condition BB. The directional electromagnetic steel plate according to any one of 7 to 7.
[Claim 9]
　Wherein an average crystal grain size of the rolling direction L obtained based on the boundary condition BC particle size RC L is defined as,
　the particle diameter RB of the average crystal grain size in the rolling direction L obtained based on the boundary conditions BB L defined as The directional electromagnetic wave according to any one of claims 1 to 8 ,
　wherein the particle size RC L and the particle size RB L satisfy 1.10 ≦ RB L ÷ RC L.
Steel plate.
[Claim 10]
　The boundary conditions the average crystal grain size of the perpendicular to the rolling direction C particle size RC determined based on the BC C is defined as,
　the direction perpendicular to the rolling direction C the average crystal grain size of the particle diameter RB of determined based on the boundary conditions BB C when defining the,
　the particle size RC C and the particle diameter RB C and is, 1.10 ≦ RB C ÷ RC C meet,
direction according to any one of claims 1 to 9, characterized in that Sex electromagnetic steel plate.
[Claim 11]
　The average crystal grain size of the rolling direction L obtained based on the boundary condition BC particle size RC L is defined as,
　the average crystal grain size of the perpendicular to the rolling direction C obtained based on the boundary condition BC grain size RC C and When defined, the direction according to any one of claims 1 to 10 ,
　wherein the particle size RC L and the particle size RC C satisfy 1.15 ≦ RC C ÷ RC L.
Electromagnetic steel plate.
[Claim 12]
　Wherein an average crystal grain size of the rolling direction L obtained based on the boundary condition BC particle size RC L is defined as,
　the particle diameter RB of the average crystal grain size in the rolling direction L obtained based on the boundary conditions BB L defined as Then,
　the average crystal grain size in the rolling orthogonal direction C obtained based on the boundary condition BC is defined as the particle size RC C, and
　the average crystal grain size in the rolling perpendicular direction C obtained based on the boundary condition BB is defined as the particle size. RB C when defining the,
　the particle size RC L and the grain size RC C and the particle diameter RB L and the grain size RB C and
　is, (RB C × RC L ) ÷ (RB L × RC C ) <1
The directional electromagnetic steel sheet according to any one of claims 1 to 11, wherein the directional electromagnetic steel sheet satisfies .0 .
[Claim 13]
　The directional electromagnetic steel according to any one of claims 1 to 12, wherein the standard deviation σ (| α |) of the absolute value of the deviation angle α is 0 ° or more and 3.50 ° or less. Steel plate.
[Claim 14]

Claims 1 to 13 are characterized 　in that, as the chemical composition, at least one selected from the group consisting of Nb, V, Mo, Ta, and W is contained in a total amount of 0.0030 to 0.030% by mass. The grain-oriented electrical steel sheet according to any one of the above.
[Claim 15]
　The grain-oriented electrical steel sheet according to any one of claims 1 to 14, wherein the magnetic domain is subdivided by at least one of applying local microstrain or forming a local groove.
[Claim 16]
　The invention according to any one of claims 1 to 15, further comprising an intermediate layer arranged in contact with the grain-oriented electrical steel sheet and an insulating film arranged in contact with the intermediate layer. Directional electrical steel sheet.
[Claim 17]
　The grain-oriented electrical steel sheet according to claim 16, wherein the intermediate layer is a forsterite film having an average thickness of 1 to 3 μm.
[Claim 18]
　The grain-oriented electrical steel sheet according to claim 16, wherein the intermediate layer is an oxide film having an average thickness of 2 to 500 nm.