Technical field
[0001]
　The present invention relates to a grain-oriented electrical steel sheet.
　Priority is claimed on Japanese Patent Application No. 2015-086299 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, a non-destructive magnetic domain control method applied to the steel sheet oriented electrical steel sheet distortion of the by non-destructive means, for example, on the surface of the steel sheet and destructive magnetic domain control methods such as forming a groove being classified.
[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]
　On the other hand, when manufacturing wound cores using grain-oriented electrical steel sheet which the grooves are imparted by destructive magnetic domain control method, since not lost grooves by practice of the strain relief annealing treatment, it is possible to maintain the magnetic domain subdivision effect . Thus, for the winding core, disruptive magnetic domain control method is generally employed as a method for reducing abnormal eddy current loss. In the case of producing the product cores for transformers because no problems such as the deformation strain of the winding core, selectively adopt either the non-destructive magnetic domain control method disruptive domain control method can do.
[0007]
　As disruptive domain control method, electrolytic etching method for forming a groove on the steel sheet surface oriented electrical steel sheet by electrolytic etching (see Patent Document 1), mechanically to press the gear surface of the steel sheet of oriented electrical steel sheet the gear pressing method of forming grooves on the surface of the steel sheet (see Patent Document 2), a laser irradiation method of forming a groove on the steel sheet surface oriented electrical steel sheet by laser irradiation (see Patent Document 3), in general It is known to specifically.
[0008]
　The electrolytic etching method, for example, after removing the insulating coating of the steel sheet surface (or the glass coating film) linearized by laser or mechanical means, by performing electrolytic etching in a portion steel is exposed, to form a groove on the steel sheet surface . When adopting such electrolytic etching method, the manufacturing process of the grain-oriented electrical steel sheet becomes complicated, resulting in a problem that manufacturing cost becomes high. Further, in the gear press method, since the steel sheet of the grain-oriented electrical steel sheet is very hard steel sheet containing Si of about 3 wt%, wear and damage of the gear is likely to occur. When adopting such gear pressing method, because the gear is a variation in the depth of the groove when worn occurs, there is a problem that the effect of reducing the abnormal eddy current loss can not be sufficiently obtained.
[0009]
　On the other hand, when employing the laser irradiation method, relatively, it is possible to form a groove easily and stably steel sheet surface, problems and gear press method of electrolytic etching method as described above problem does not occur. Accordingly, in recent years, as the magnetic domain control method of a grain-oriented electromagnetic steel sheet, the laser irradiation method is adopted widely.
CITATION
Patent Literature
[0010]
Patent Document 1: Japanese Patent Publication 62-54873 Patent Publication
Patent Document 2: Japanese Patent Publication 62-53579 Patent Publication
Patent Document 3: Japanese Patent Laid-Open 6-57335 discloses
Summary of the Invention
Problems that the Invention is to Solve
[0011]
　When employing the laser irradiation method as domain control method of a grain-oriented electrical steel sheet, after the insulating film is formed on the surface of the steel sheet by irradiating a laser toward the surface of the steel sheet from above the insulating film, the surface of the steel sheet to form a groove and the like as one of the manufacturing processes. In this case, since the groove immediately after the laser irradiation is exposed to the outside, to prevent rusting in the groove, after the groove formation, again, it is necessary to form an insulating film on the steel plate.
[0012]
　The thickness of the insulating film in the groove is formed region is greater than the thickness of the insulation coating in other areas, adhesion between the steel sheet and the insulating film at the grooved region, and other regions worse compared to. As a result, cracks or peeling is likely to occur in the insulating film of the peripheral groove. A crack or peeling occurs in the insulating film, rust is likely to occur in the steel sheet.
　Thus, when employing the laser irradiation method as domain control method of the grain-oriented electrical steel sheet, rust resistance of the grain-oriented electrical steel sheet is lowered. For example, rust is the film near its peeling occurs, if the interlayer current flows significantly there is a possibility that the iron loss is increased. Furthermore Should you steel by rust has eroded spread nonmagnetic portion, the optimum magnetic domain refining conditions may sometimes not maintained.
　Before the on the surface of the steel sheet insulating coating is formed, a groove is formed in the surface of the steel sheet by laser irradiation, even in the case of adopting the manufacturing process of subsequently forming a surface insulating film of the steel sheet, the problem occurs.
[0013]
　The present invention has been made in view of the above problems, and an object thereof is to improve the rust resistance of the grain-oriented electrical steel sheet in which the grooves on the surface of the steel sheet is formed for domain refining.
Means for Solving the Problems
[0014]
　The gist of the present invention is as follows.
(1) grain-oriented electrical steel sheet according to an embodiment of the present invention comprises a steel plate having grooves and the groove depth direction extends in a direction crossing the rolling direction is the thickness direction is formed steel sheet surface, when viewed the groove in groove longitudinal cross section including the Mizonobe extension direction and the thickness direction, the arithmetic mean height Ra of the roughness curve forming the contour of the groove bottom region of the groove is at 1μm or more 3μm or less, the average length RSm of a roughness curve element forming the contour of the groove bottom region is 10μm or more 150μm or less. The oriented electrical steel sheet further comprises an insulating film, when viewed with the grooves in the groove widthwise cross section perpendicular to the Mizonobe extending direction, starting from the boundary between the groove and the steel sheet surface, the groove widthwise sectional when the 10μm or 500μm following areas away from orthogonal and the groove and the thickness direction is defined as a particle existing area at the insulating film in the particles present area, the circle equivalent diameter of 0.1μm or more 2μm comprises iron-containing particles or less, the ratio of the area of the iron-containing particles to the area of particle existence region is less than 30% than 0.1%, the chemical composition of the iron-containing particles, 80 to 100 wt% including between Fe, and 0-10 wt% of Si, and 0 to 10 wt% Mg.
[0015]
(2) oriented electrical steel sheet according to (1) may be further provided with a glass coating film between the steel sheet and the insulating film. In this case, as compared with the average content of Mg in mass fraction contained in the glass film and the insulating film, the glass coating film and the insulating film in the Mg content satisfies the above 1.3 times the average when a region is defined as Mg concentrated region, when viewed with the grooves in the groove widthwise cross section perpendicular to the Mizonobe extension direction, the Mg concentrated region, starting from the boundary between the groove and the surface of the steel sheet it may be included in the 0.1μm or 10μm following areas away from orthogonal and the groove and the plate thickness direction in the groove widthwise cross section. Further, when viewed the groove from the plate thickness direction, the Mg concentrated region is continuously present along the Mizonobe extending direction, or a plurality of the Mg concentrated region is along the Mizonobe extension direction there have intervals Te, the distance between the adjacent along the Mizonobe extension direction Mg concentrated region may be not greater than 0 100μm or less.
[0016]
(3) in the oriented electrical steel sheet according to the above (2), on the groove, and the average thickness is less than 5μm or more 0μm glass coating film, the average thickness of the said insulating coating of 1μm or 5μm or less is formed in which, on the steel sheet, the mean and thickness 5μm or less of the glass coating film above 0.5 [mu] m, an average and a thickness is formed and the insulating film of 1μm or 5μm or less, is formed on the groove the the average thickness of the glass coating film may be thinner than the average thickness of the glass coating film formed on the steel sheet.
[0017]
(4) In the oriented electrical steel sheet according to any one of the above (1) to (3), the grain size of the crystal grains may be 5μm or more in contact with the groove in the steel sheet.
Effect of the invention
[0018]
　According to this aspect of the present invention, it is possible to improve the rust resistance of the oriented electrical steel sheet in which grooves are formed on the surface of the steel sheet for domain refining.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
FIG. 1 is a plan view of a grain-oriented electrical steel sheet 1 according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1 (a view as viewed groove 5 in cross-section including the Mizonobe extension direction).
3 is a sectional view taken along line the line B-B in FIG. 1 (Mizonobe view of the groove 5 in the cross section perpendicular to the lengthwise direction).
4 is a first explanatory view relating to the definition of the groove base line BL of the groove 5.
It is a second explanatory diagram concerning the definition of the groove base line BL in FIG. 5A] groove 5.
Is a third explanatory view relating to the definition of the groove base line BL in FIG. 5B] groove 5.
6 is a fourth explanatory diagram relating to the definition of the groove base line BL of the groove 5.
Is [7] illustration on defining the groove bottom region 5a of a by and grooves 5 a cross-sectional view taken along a line C-C of FIG.
8 is a schematic diagram showing a roughness curve RC which forms the contour of the groove bottom region 5a.
[9] and the groove area 5b a cross-sectional view taken along line E-E in FIG. 6, the steel sheet region 2b, an explanatory diagram relating to the definition of particle existence regions W1 and Mg concentrated region W2.
Is a schematic diagram showing the Mg concentrated region W2 when viewing the groove 5 from FIG. 10 thickness direction Z.
Is a flowchart showing a manufacturing process of FIG. 11 oriented electrical steel sheet 1.
It is a first explanatory view relating to a laser irradiation step S08 in FIG. 12 oriented electrical steel sheet 1 of the manufacturing process.
It is a second explanatory view relating to a laser irradiation step S08 in FIG. 13A] oriented electrical steel sheet 1 of the manufacturing process.
It is a third explanatory view relating to a laser irradiation step S08 in FIG. 13B] oriented electrical steel sheet 1 of the manufacturing process.
14 is a fourth explanatory view relating to a laser irradiation step S08 in the oriented electrical steel sheet 1 of the manufacturing process.
DESCRIPTION OF THE INVENTION
[0020]
　It will be described in detail preferred embodiments of the present invention. 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.
[0021]
　It will be described in detail with reference to the accompanying drawings, an embodiment of the present invention.
　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. Figure 3 is a cross-sectional view taken along line B-B of FIG. Note that, in FIGS. 1 to 3, the rolling direction of the grain-oriented electrical steel sheet 1 X, grain-oriented electrical steel sheet 1 in the sheet width direction (direction perpendicular to the rolling direction in the same plane) Y, of the grain-oriented electrical steel sheet 1 the thickness direction (direction perpendicular to the XY plane) is defined as Z.
[0022]
　As shown in FIGS. 1-3, the grain-oriented electrical steel sheet 1, in combination with the cold rolling process and annealing process, the crystal orientation as the crystal grains of the easy magnetization axis and the rolling direction X matches is controlled a steel plate (the base steel) 2, a glass coating film 3 formed on the surface of the steel plate 2 (the surface of the steel sheet 2a), and an insulating film 4 formed on the surface of the glass coating film 3.
[0023]
　As shown in FIG. 1, the surface of the steel sheet 2a, for domain refining, a plurality of grooves 5 and the groove depth direction extends in a direction coincides with the thickness direction Z crossing the rolling direction X, They are formed at predetermined intervals along the rolling direction X. That is, FIG. 2, the one groove 5, a diagram viewed in cross-section including the Mizonobe running direction and the thickness direction Z. 3, the one groove 5, a diagram viewed in cross section perpendicular to Mizonobe lengthwise direction. Incidentally, the groove 5 may be provided so as to cross the rolling direction X, need not necessarily Mizonobe the extending direction and the rolling direction X is perpendicular. However, in the present embodiment, for convenience of descriptions, illustrate the case where the Mizonobe extending direction and the rolling direction X is perpendicular. The groove 5, when viewed from a thickness direction Z (if the grooves 5 in a plan view), may have an arcuate shape. However, in the present embodiment, for convenience of descriptions, it illustrates the groove 5 having a linear shape.
[0024]
　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.
[0025]
　Chemical components of the steel plate 2 is a preferred chemical composition in order to control the crystal orientation {110} <001> to Goss texture was integrated in orientation. Among the 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.
[0026]
　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 angle from the central position of the steel plate 2 after film removal, by Shimadzu ICPS-8100, etc. (measuring device), by measuring under the conditions based on a previously prepared calibration curve It can be identified. Incidentally, C and S are combustion - infrared absorption method using, N is the inert gas fusion - can be measured with a thermal conductivity method.
[0027]
　Glass film 3, for example, forsterite (Mg 2 SiO 4 ), spinel (MgAl 2 O 4 ), or 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 3, the finish annealing step which 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 3 is not an essential element as a component of a grain-oriented electrical steel sheet 1.
[0028]
　Insulating film 4, 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.
[0029]
　Incidentally, the glass coating film 3 and the insulating film 4 of a 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 3 or insulating coating 4, NaOH: 10% by mass + H 2 O: 90 wt% aqueous sodium hydroxide for 15 minutes at 80 ° C., immersion. 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 the 90 wt% nitric acid aqueous solution, 1 minute weak at room temperature, washed immersed in. Finally, one minute less than with a blower of hot air and dried. Note that when removing the glass coating film 3 or insulating coating 4 from oriented electrical steel sheet 1 by the method described above, the shape and roughness of the groove 5 of the steel plate 2 is equivalent to the before forming a glass coating film 3 or insulating coating 4 it has been confirmed that there is.
[0030]
　Oriented electrical steel sheet 1 according to this embodiment has a characteristic structure for improving the rust resistance, the following three configurations A, B, C, and D.
　The value of (A) a surface roughness parameter indicating the surface roughness of the groove bottom region of the groove 5 (Ra, RSm) is within a predetermined range.
　(B) it is preferred that the insulating film 4 contains an iron-containing particles.
　The (C) glass coating film 3 and the insulating film 4, it is preferable that Mg concentrated region exists along the Mizonobe extension direction at a position adjacent to the groove 5.
　(D) the particle size of the crystal grains in contact with the steel plate 2 in the grooves 5 is preferably 5μm or more.
　Hereinafter, the configuration A, B, C, and will be described in detail for each D.
[0031]
[Structure A]
　in the present embodiment, as shown in FIG. 2, Mizonobe grooves 5 in lengthwise direction section (in the present embodiment the direction parallel to the sheet width direction Y) including and a thickness direction Z (grooves lengthwise section) the when viewed, the arithmetic mean height Ra of the roughness curve forming the contour of the groove bottom region 5a of the groove 5 is at 1μm or more 3μm or less, preferably 1.2μm or 2.5μm or less, further preferably is at 1.3μm or 2.3μm or less, an average length RSm of a roughness curve element forming the contour of the groove bottom region 5a is, it is 10μm or more 150μm or less, preferably 40μm or more 145μm or less, more preferably it is 60μm above 140μm or less.
[0032]
　By surface roughness parameters (Ra, RSm) satisfies the above range, since the groove bottom region 5a is roughened constant degree, the adhesion between the steel plate 2 and the glass coating film 3 or the insulating film 4 by the anchor effect improves. Therefore, cracks or peeling hardly occurs in the glass coating film 3 or the insulating film 4 in the peripheral groove 5. As a result, rust resistance of the groove 5 oriented electrical steel sheet 1 which is formed on the surface of the steel plate 2 for domain refining is improved.
[0033]
　Meanwhile, as shown in FIG. 3, in the width direction of the groove 5, the depth of the groove 5 is not necessarily constant. Therefore, it is necessary to clarify the groove bottom region 5a when viewing the groove 5 in the groove longitudinal section. Hereinafter, an example of a specific method of the groove bottom region 5a when viewing the groove 5 in the groove longitudinal section.
[0034]
　As shown in FIG. 4, when viewing the groove 5 from a thickness direction Z (if the grooves 5 in a plan view), the observation range 50 and sets a part of the groove 5, along the Mizonobe extension direction more set virtually virtual lines L1 ~ Ln the observation range 50 of the (n lines). Observation range 50 is a region (i.e., a region where the shape of the groove bottom is stable) excluding the end portions in the extending direction of the groove 5 is preferably set to. For example, the observation range 50, the length of Mizonobe extension direction may be the observation region such that approximately 300 [mu] m. Next, using a laser type surface roughness measuring instrument or the like, as measured along the surface roughness of the groove 5 to the virtual line L1, as shown in FIG. 5A, the measurement cross-section forming a Mizonobe extending direction of the contour of the groove 5 curve MCL1 is obtained in line with imaginary line L1.
[0035]
　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. 5B, waviness curve LWC1 forming a Mizonobe extending direction of the contour of the groove 5 can be obtained in line with imaginary line L1. Waviness curve is a kind of contour curve together with the roughness curve described later, a roughness curve is particularly surface roughness of the contour whereas a profile curve that is suitable to indicate accurately, waviness curve contour a profile curve that is suitable for simplifying the shape itself in smooth lines.
[0036]
　As shown in Figure 5B, the use of waviness curve LWC1, at each location of the plurality along the imaginary line L1 (m pieces), the thickness between the outline of the steel sheet surface 2a and the groove 5 (i.e. waviness curve LWC1) distance direction Z (depth d1 ~ dm: unit [mu] m) is obtained. Further, the average value of these depths d1 ~ dm (groove average depth D1) is obtained. The same measurement technique, for each well of the other virtual lines L2 ~ Ln, groove average depth D2 ~ Dn is obtained.
　In order to measure the distance between the contour of the steel sheet surface 2a and the groove 5 (waviness curve LWC1), it is necessary to measure the position of the steel sheet surface 2a in the Z direction (height) previously. For example, for each of a plurality of locations on the steel sheet surface 2a in the observation range 50, using a laser type surface roughness measuring instrument measures the position in the Z direction (height), the measurement results of the average surface of the steel sheet 2a it may be used as the height.
[0037]
　In this embodiment, among the virtual lines L1 ~ Ln, and a groove average depth along the Mizonobe extension direction is to select a virtual line which satisfies the condition that maximizes the groove base line BL. Groove depth D of the groove 5 and groove average depth of the groove base line BL (unit [mu] m) to define. For example, as shown in FIG. 6, of the groove average depth D1 ~ Dn obtained for each of the virtual lines L1 ~ Ln, when the groove average depth D3 is maximum, virtual line L3 and the groove base line BL is defined, the groove average depth D3 of the virtual line L3 is defined as the groove depth D of the groove 5. Groove depth D of the groove 5 in this embodiment, in order to obtain preferred effects of magnetic domain refining is preferably 5μm or 40μm or less.
　In order to obtain preferred effects of magnetic domain refining is preferably the groove width W of the groove 5 in this embodiment is 10 [mu] m ~ 250 [mu] m. The groove width W is on the waviness curve of the groove 5 in the groove widthwise cross section perpendicular to Mizonobe lengthwise direction, a depth toward the surface of the groove 5 from the surface of the steel sheet 2a in the thickness direction Z is, the groove of the groove 5 deep is may be obtained as the length of the line segment (groove opening) connecting the two points to be 0.05 × D to D (see FIG. 9).
[0038]
　Figure 7 is a cross-sectional view taken along line C-C of FIG. That is, FIG. 7 is a view of the groove 5 in the groove longitudinal cross section including a groove base line BL and the plate thickness direction Z of the above. In this embodiment, as shown in FIG. 7, when viewing the groove 5 in the groove longitudinal cross section including a groove base line BL and the plate thickness direction Z, the contour of the groove 5 appearing in the observation range 50 and the groove bottom region 5a Define.
[0039]
　The groove bottom region 5a of the groove 5 are identified by the methods described above. That is, in this embodiment, as shown in FIG. 8, obtained by converting the measured profile curve forming the contour of the groove bottom region 5a of the groove 5 appearing in the groove longitudinal cross section including a groove base line BL and the plate thickness direction Z arithmetic average height Ra of the roughness curve RC was found is at 1μm or more 3μm or less, preferably 1.2μm or 2.5μm or less, or less even more preferably 1.3μm or more 2.3 .mu.m, the groove bottom the average length RSm of a roughness curve element obtained by converting the measured profile curve forming the outline of the region 5a is, it is 10μm or more 150μm or less, preferably 40μm or 145μm or less, further preferably 60μm or 140μm or less it is. Roughness curve RC, after obtaining section curves by applying a low-pass filter cut-off values ​​λs on the measurement cross section curves obtained for the groove reference line BL, and a high-pass filter in its cross-section curve (cut-off value [lambda] c) by applying, obtained by excluding the long wavelength component from the profile curve. Mean definition of length RSm of the roughness curve RC of the arithmetic mean height Ra and roughness profile elements are according to Japanese Industrial Standards JIS B0601 (2013).
[0040]
Structure B for]
　As shown in FIG. 3, in this embodiment, when viewing the groove 5 in the groove widthwise cross section perpendicular to Mizonobe lengthwise direction, starting from the boundary G between the groove 5 and the steel sheet surface 2a, It defines the area extending grooves shorter perpendicular in cross-section and the thickness direction Z and in a direction away from the groove 5 10 [mu] m or more 500μm or less in length and particle existence region W1.
[0041]
　As shown in FIG. 3, in this embodiment, the insulating film 4 in the particle existence region W1 is equivalent circle diameter contains the iron-containing particles 6 is 0.1μm or more 2μm or less. The ratio of the area of ​​the iron-containing particles 6 to the area of ​​particle existence region W1 is less than 30% 0.1% or more. Here, the area of ​​the iron-containing particles 6, the area of ​​the iron-containing particles 6 a plurality present in the particle existence region W1 of the insulating film 4 sum of (surface area of ​​the particles) (total area). If the proportion of the area of ​​the iron-containing particles 6 to the area of ​​particle existence region W1 is 0.1% or more increases the strength of the insulating film 4, cracking of the insulation due to cracking film 4 is reduced, as a result, directionality rust resistance of the electromagnetic steel sheet 1 is improved. Therefore, it is preferable that the ratio of the area of ​​the iron-containing particles 6 to the area of ​​particle existence region W1 is 0.1% or more. On the other hand, if the ratio of the area of ​​the iron-containing particles 6 to the area of ​​particle existence region W1 is more than 30%, increased conductivity due to iron, flow short-circuit current by an interlayer resistance decreases, the vortex of the grain-oriented electrical steel sheet 1 current loss increases. Therefore, the ratio of the area of ​​the iron-containing particles 6 to the area of ​​particle existence region W1 is preferably less than 30%. Iron-containing particles 6, containing 100% iron 80% by mass fraction. Iron-containing particles 6 is a mass fraction, and at least 0% to 10% of Si, may further contain a Mg of 0% to 10%.
[0042]
　Satisfies the width above range of particle existence regions W1, by circle equivalent diameter and the area of ​​the iron-containing particles 6 satisfies the above range and, therefore improves the strength of the insulating film 4 in the particle existence region W1, near the groove 5 cracks or delamination hardly occurs in the insulating film 4. As a result, rust resistance of the groove 5 oriented electrical steel sheet 1 which is formed on the surface of the steel plate 2 for domain refining is improved.
[0043]
　Meanwhile, when observing a groove widthwise cross section of the groove 5 with an electron microscope or the like, there is a case the boundary G between the groove 5 and the steel sheet surface 2a is unclear. Therefore, it is necessary to clarify the boundary G between the groove 5 and the steel sheet surface 2a. Hereinafter, an example of a specific method of boundary G between the groove 5 and the steel sheet surface 2a when viewing the groove 5 in the groove widthwise cross section.
[0044]
　Figure 9 is a cross-sectional view taken along line E-E of FIG. That is, FIG. 9 is a view of the groove 5 in the groove widthwise cross section perpendicular to Mizonobe lengthwise direction. As shown in FIG. 9, the groove when the widthwise sectional view of the groove 5, the groove and the short groove 5 appearing in the cross section measurement section curved groove widthwise waviness curve SWC those converted into waviness curve forming the contour Define. As shown in FIG. 9, it sets a virtual line Ls perpendicular to the groove base line BL in the XY plane virtually, by using a laser type surface roughness measuring instrument or the like, the surface roughness of the steel plate 2 including the groove 5 as measured along a virtual line Ls of the measurement profile curve forming the outline of the groove 5 in the groove widthwise cross section obtained in line with imaginary line Ls.
[0045]
　Groove widthwise waviness curve SWC is appearing in the groove widthwise cross section, after obtaining a profile curve by applying a low pass filter (cut-off value [lambda] s) to the measured profile curve obtained for the imaginary line Ls as described above, the profile curve to the band filter (cut-off value .lambda.f, [lambda] c) by applying, obtained by excluding the longer wavelength component and a shorter wavelength component from the cross section curve.
[0046]
　As shown in FIG. 9, the use of groove widthwise waviness curve SWC forming the contour of the groove 5 appearing in the groove widthwise cross-section at each location of the plurality (p number) along the virtual line Ls, the surface of the steel sheet 2a and the groove thickness direction Z distance between the 5 contour (i.e. groove widthwise waviness curve SWC) (depth f1 ~ fp: unit [mu] m) is obtained. In the present embodiment, as shown in FIG. 9, the groove widthwise waviness curve SWC, defines an area that satisfies the following conditional expression (2) defines a groove region 5b, the region other than the trench regions 5b and the steel sheet region 2b to. The boundary between the groove region 5b and the steel sheet region 2b is identified as a boundary G between the groove 5 and the steel sheet surface 2a. The width of the trench region 5b corresponds to the groove width W.
　　　　　　　　　　　≧ 0.05 × fi D ... (2)
　　　　　　　　　(where, i is an integer of 1 ~ p)
[0047]
Structure C for]
　In the present embodiment, among the glass coating film 3 and the insulating film 4, compared to the average content of Mg in mass fraction contained in the glass coating film 3 and the insulating film 4, the Mg content is on average the region that satisfies the above 1.3 times is defined as Mg concentrated region W2. As shown in FIG. 3, in this embodiment, when viewing the groove 5 in the groove widthwise cross section perpendicular to Mizonobe extending direction, the above-mentioned Mg concentrated region W2 is the boundary between the groove 5 and the steel sheet surface 2a G the starting, are included in the thickness direction Z perpendicular to and 10μm following areas direction 0.1μm or more away from the groove 5 in the groove widthwise cross section.
[0048]
　In other words, the average content of Mg in mass fraction of the glass coating film 3 and the insulating film 4 in the Mg concentrated region W2 shown in FIG. 3, the average content of Mg in mass fraction contained in the glass coating film 3 and the insulating film 4 it is compared to 1.3 times or more and. As described above, the boundary between the groove region 5b and the steel sheet region 2b is identified as a boundary G between the groove 5 and the surface of the steel sheet 2a (see FIG. 9).
[0049]
　Further, as shown in FIG. 10, when viewing the groove 5 from a thickness direction Z (if the grooves 5 in a plan view), the above Mg concentrated region W2 is there are a plurality along the Mizonobe extension direction . In this case, Mizonobe distance dw between the Mg concentrated region W2 adjacent to each other along the extension direction is greater than 0 100μm or less. Or, Mg concentrated region W2 may be present continuously along the Mizonobe extension direction. Incidentally, Mg content may be measured using the EPMA (Electron Probe Micro Analyser) or the like.
[0050]
　The width of Mg concentrated region W2 is included in the above range, by the distance dw between the Mg concentrated region W2 adjacent to each other are included in the above range, firmly bonding the insulating film 4 and the steel plate 2 surface since the crack or peeling hardly occurs in the insulating film 4 around the groove 5. As a result, rust resistance of the groove 5 oriented electrical steel sheet 1 which is formed on the surface of the steel plate 2 for domain refining is improved.
[0051]
[Configuration D]
　In the present embodiment, the steel plate 2, it is preferred particle size of the crystal grains in contact with the groove 5 is 5μm or more in average. Surrounding groove 5, when there is a melt solidified region derived from the formation of the groove 5, the particle diameter of crystal grains in contact with the groove 5 becomes fine. In this case, the final crystal orientation {110} <001> may deviate from the orientation becomes high, may not be obtained preferably magnetic properties becomes high. Therefore, the periphery of the groove 5, it is preferred that no melting and solidification region. If there is no melt-solidified region around the groove 5, the particle diameter of the crystal grains in contact with the groove 5 (the secondary recrystallized grains) is 5μm or more in average. Although not limit the grain size of the crystal grains in contact with the groove 5 is not particularly limited, the upper limit 100 × 10 3 may μm or less. 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 groove 5 may be observed in the above groove widthwise cross-section or the thickness direction Z perpendicular cross section.
　Groove no melt solidification region of the 5, for example, it can be obtained by the manufacturing method described below.
[0052]
　As described above, according to this embodiment, it is possible to greatly improve the steel sheet surface 2a to the rust resistance of a grain-oriented electrical steel sheet 1 which groove 5 is formed for domain refining.
[0053]
　Further, as shown in FIG. 3, in the above embodiment, the groove 5 the absence of the glass coating film 3 (groove region 5b) (average thickness that is the glass coating film 3 is a state of 0 .mu.m) illustrates, the groove 5, the average thickness of the glass coating film 3 below 0μm super 5 [mu] m, an average thickness may be arranged and 5 [mu] m below the insulation coating 4 or 1 [mu] m. Further, the surface of the steel sheet 2a (steel region 2b), and the glass coating film 3 of 0.5μm or more 5μm or less the average thickness, the average thickness of the and 5μm or less of the insulating film 4 over 1μm may be disposed. Furthermore, the average thickness of the glass coating film 3 in the groove 5 may be thinner than the average thickness of the glass coating film 3 in the steel sheet surface 2a.
[0054]
　As described above, by setting the thickness of the glass coating film 3 and the insulating film 4, since the cracking or peeling is less likely to occur in the insulating film 4 around the groove 5, rust resistance of the grain-oriented electrical steel sheet 1 There is further improved. Further, by adopting a configuration in which no glass film 3 in the groove 5 (that is configured average thickness of the glass coating film 3 is 0μm in groove 5), the walls of the grooves facing each other the distance (groove width) since it is possible to more narrowly, it is possible to further improve the magnetic domain refining effect by the groove 5 (that is the effect of reducing the abnormal eddy current loss).
[0055]
　The direction in the above embodiment has exemplified the oriented electrical steel sheet 1 with a glass coating film 3, since the glass film 3 is not an essential component, as, to be composed of only the steel plate 2 and the insulating film 4 for even sex electromagnetic steel sheets, by applying the present invention, it is possible to obtain a rust resistance improving effect. The grain-oriented electrical steel sheet comprised of only the steel plate 2 and the insulating film 4, the groove 5 (groove region 5b), the average thickness is disposed 5μm or less of the insulating film 4 over 1 [mu] m, the surface of the steel sheet 2a (steel region 2b) , the average thickness is 5μm or less of the insulating film 4 over 1μm may be disposed.
[0056]
　Next, a method for manufacturing a grain-oriented electrical steel sheet 1 according to this embodiment.
　Figure 11 is a flowchart showing a manufacturing process of the grain-oriented electrical steel sheet 1. As shown in FIG. 11, 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.
[0057]
　Subsequently, the hot-rolling step S02, after the slab obtained from the casting step S01 is heated to a predetermined temperature (e.g. 1150 ~ 1400 ° C.), the hot rolling is performed on the slabs. Thus, for example, hot-rolled steel sheet is obtained having a thickness of 1.8 ~ 3.5 mm.
[0058]
　Subsequently, the annealing step S03, with respect to hot-rolled steel sheet obtained from hot rolling step S02, the annealing treatment under a predetermined temperature condition (e.g., conditions of heating at 750 - 1200 ° C. 30 seconds to 10 minutes) It is carried out. Subsequently, the cold-rolling step S04, after the pickling process is carried out on the surface of the hot-rolled steel sheet annealing process is performed at the annealing step S03, the cold rolling is performed on the hot-rolled steel sheet. Thus, for example, cold rolled steel sheet is obtained having a thickness of 0.15 ~ 0.35 mm.
[0059]
　Subsequently, the decarburization annealing step S05, with respect to cold-rolled steel sheet obtained from the cold-rolling step S04, under a predetermined temperature condition (e.g., conditions of heating 1-3 minutes at 700 ~ 900 ° C.) heat treatment ( that is, the 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)
[0060]
　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., finish annealing treatment) 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 5 of the cold-rolled steel sheet (i.e. oriented electrical steel sheet 1 which crystal orientation is controlled so that the crystal grains of the easy magnetization axis and the rolling direction X coincide steel 2) in a state before forming is obtained.
[0061]
　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 3 containing) composite oxide or the like is formed. In the finish annealing step S07, finish annealing process is performed in a state in which the steel plate 2 is coiled. By glass coating film 3 is formed on the surface of the steel plate 2 during the finish annealing process, it is possible to prevent the burn-in steel plate 2 which is coiled occurs.
[0062]
　Plurality Then, the laser irradiation step S08, by irradiating the laser with respect to the glass coating film 3 is formed steel sheet second surface (one side only), the surface of the steel plate 2, extending in a direction crossing the rolling direction X grooves 5 of are formed at predetermined intervals along the rolling direction X. Hereinafter, with reference to FIGS. 12 to 14, it will be described in detail laser irradiation step S08.
[0063]
　As shown in FIG. 12, in the laser irradiation step S08, the laser YL is 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 YL on the surface of the steel plate 2, to scan the laser YL steel 2 in the plate width direction Y and substantially parallel.
[0064]
　Simultaneously with the irradiation of the laser YL, assist gas 25 such as air or an inert gas, is blown to the portion of the steel plate 2 which laser YL is irradiated. The inert gas, for example, nitrogen or argon. Assist gas 25 is responsible for removing the scattered or vaporized components from the steel plate 2 by the laser irradiation. By blowing the assist gas 25, since the laser YL reaches the steel plate 2 without being inhibited by the scattered or vaporized components of the groove 5 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 5 along a scanning line of the laser YL is formed.
[0065]
　In the laser irradiation step S08, while being conveyed along the sheet passing direction steel plate 2 coincides with the rolling direction X, the laser YL is irradiated to the surface of the steel plate 2. Here, as the grooves 5 are formed along the rolling direction X at a predetermined interval PL, 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. 12, the surface of the steel plate 2, a plurality of grooves 5 crossing the rolling direction X, it is formed at predetermined intervals PL along the rolling direction X.
[0066]
　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 groove 5 in a stable manner may be used pulsed laser or a continuous wave laser, a laser light source. As the laser YL, light harvesting high, it is preferable to use a single mode laser suitable for forming the grooves.
[0067]
　As the irradiation conditions of the laser YL, e.g., a laser output to 200 W ~ 2000 W, (diameter containing 86% of i.e. laser output, 86% diameter abbreviated described below) condensing spot diameter in the rolling direction X of the laser YL a 10 [mu] m ~ to 1000 .mu.m, focusing spot diameter in the sheet width direction Y of the laser YL (86% diameter) in 10 [mu] m ~ 1000 .mu.m, the laser scanning speed 5m / s ~ 100m / s, the laser scanning pitch (interval PL) of 2 mm ~ 10 mm it is preferable to set in. As desired groove depth D is obtained, it may be suitably adjusted to these laser irradiation conditions. For example, in the case of obtaining a deeper groove depth D is set slow laser scanning speed may be set higher laser output.
[0068]
　As shown in FIG. 13A, the laser irradiation step S08 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 (the plate of the laser YL from a direction with the inclination of the first angle θ1 with respect to a direction parallel) in the width direction Y, the assist gas 25 is injected so as to follow the laser YL. Further, as shown in FIG. 13B, when viewed the steel sheet 2 is conveyed along the sheet passing direction TD from the plate width direction Y (the laser scanning direction SD), the inclination of the second angle θ2 with respect to the steel sheet surface 2a from a direction with the assist gas 25 is injected so as to follow the laser YL. The first angle θ1 is preferably set in a range of more than 90 ° less than 180 °, the second angle θ2 is preferably set in the range of 1 ° or more 85 ° or less. 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.
[0069]
　In particular, by the first angle θ1 is assist gas injection angle with respect to the laser scanning direction is set in the above range, the surface roughness of the groove bottom region 5a and (Ra, RSm) can be accurately controlled. In addition, by the quantity of particles having a size of at least 0.5μm present in the sheet passing atmosphere set in the above range, the surface roughness of the groove bottom region 5a (especially RSm) can be more accurately controlled . In particular, by the flow rate of the assist gas 25 is set in the above range, can be accurately controlled range and spacing dw of Mg concentrated region W2. Further, in particular, by a second angle θ2 is assist gas injection angle relative to the surface of the steel sheet 2a is set in the above range, it can be accurately controlled range of particle existence region W1, the equivalent circle diameter and area of ​​the iron-containing particles 6 .
[0070]
　Conventionally, when forming the groove by the laser irradiation, the direction (thickness direction) perpendicular to the steel sheet surface, was injected toward the assist gas to the steel sheet surface so as to follow the laser. In contrast, the present inventors have conducted intensive studies to define the direction of injection assist gas 25 three-dimensionally as shown in FIGS. 13A and 13B, further assist gas 25 flow rate and in Tsuban atmosphere by also particle amount specified, the surface roughness of the groove bottom region 5a (Ra, RSm) as well as the range and distance dw of Mg concentrated region W2, range of particle existence regions W1, yen equivalent iron-containing particles 6 It found that the diameter and area can be accurately controlled.
[0071]
　The present inventors have, by a novel manufacturing method as described above, the configuration A, B, when manufacturing a grain-oriented electrical steel sheet having a C and D, the rust resistance of the oriented electrical steel sheet is improved the heading, is to have completed the present invention. Therefore, the manufacturing method of the grain-oriented electrical steel sheet according to the present embodiment (in particular laser irradiation step) is a novel manufacturing method by those skilled in the art can not expect, the grain oriented electrical steel sheet 1 also those skilled obtained thereby new configuration a which can not be predicted, B, and has a C and D.
[0072]
　By one laser irradiation apparatus 10, when it is difficult to form the groove 5 in the entire plate width direction Y of the steel plate 2, as shown in FIG. 14, by using the laser irradiation apparatus 10 in a plurality, a groove may be formed 5 across the plate width direction Y of the steel plate 2. In this case, as shown in FIG. 14, 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. By adopting the laser irradiation method shown in this FIG. 14, it is possible to form a plurality of grooves 5 as shown in FIG. 1 on the surface of the steel sheet 2a.
[0073]
　Referring back to FIG. 11, the end of the insulating film forming step S09, the laser irradiation process steel sheet surface 2a of the groove 5 is formed by S08 described above, containing, for example, colloidal silica and phosphate insulation coating liquid is applied from above the glass coating film 3. Then, by heat treatment under predetermined temperature conditions (e.g. 840 ~ 920 ° C.) is carried out, finally, as shown in FIGS. 1 to 3, the steel plate 2 groove 5 is formed, the glass coating film 3 and and an insulating film 4, and configurations a, B, and grain-oriented electrical steel sheet 1 having a C and D are obtained.
[0074]
　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.
[0075]
　In the above embodiment, before the insulating film 4 is formed on the surface of the steel sheet 2a, a groove 5 on the surface of the steel sheet 2a by the laser irradiation, a manufacturing process of subsequently forming an insulating film 4 on the surface of the steel sheet 2a the case of employing illustrated. In the present embodiment, not limited to this, after the insulating film 4 is formed on the surface of the steel sheet 2a, by irradiating a laser YL toward the surface of the steel sheet 2a from above the insulating film 4, the groove 5 on the surface of the steel sheet 2a it may be adopted a manufacturing process of forming. In this case, since the groove 5 immediately after the laser irradiation is exposed to the outside, after the formation of the groove 5, again, it is necessary to form the insulating film 4 on the steel plate 2. Or, in this embodiment, after the groove 5 is formed on the steel plate 2, the glass coating film 3 or insulating coating 4 may be formed.
[0076]
　Therefore, the grain-oriented electrical steel sheet according to the present embodiment include, but are oriented electrical steel sheet 1 which high-temperature annealing has the completed and coating of the glass coating film 3 and the insulating film 4 has been completed for the secondary recrystallization, similarly to also include oriented electrical steel sheet after the it was and groove 5 is formed before the coating of the glass coating film 3 or insulating coating 4 is completed. 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 coating film 3 or insulating coating 4. Incidentally, as described above, when removing the glass coating film 3 or the insulating film 4 by the above-described film removal process from the glass coating film 3 or insulating coating 4 oriented electrical steel sheet 1 which is formed, the shape and roughness of the groove 5 it has been confirmed that the equivalent before forming the glass coating film 3 or insulating coating 4.
[0077]
　In the above embodiment, a case has been exemplified for implementing the laser irradiation step S08 after the finish annealing step S07, the laser irradiation step may be carried out between the cold rolling steps S04 and decarburization annealing step S05 . 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 trench 5 on the steel sheet surface 2a of the cold-rolled steel sheet, leaving for the cold-rolled steel sheet charcoal annealing may be performed.
Example
[0078]
　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.
[0079]
[Rust resistance verification 1]
　First, to verify the rust resistance of the grain-oriented electrical steel sheet satisfying the following conditions 1 and 2.
　(Condition 1)
　when viewing the groove in the groove longitudinal section, the arithmetic mean height Ra of the roughness curve forming the contour of the groove bottom region of the groove, it is 1μm or more 3μm or less.
　(Condition 2)
　when viewing the groove in the groove longitudinal section, an average length RSm of a roughness curve element forming the contour of the groove bottom region of the groove is 10μm or more 150μm or less.
[0080]
　Oriented electrical steel sheet used in this validation 1 was prepared as follows.
　In mass fraction, Si: 3.0%, C: 0.08%, acid-soluble Al: 0.05%, 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%, containing and the balance hot rolling is performed on a slab having a chemical composition consisting of Fe and impurities, hot-rolled steel plate having a thickness of 2.3mm was obtained.
[0081]
　Subsequently, to the above hot-rolled steel sheet, annealing under temperature conditions of heating for 1 minute was performed at 1000 ° C.. After the pickling treatment is carried out on the surface of the hot-rolled steel sheet annealing process is performed, cold rolling is performed on the hot-rolled steel sheet, cold-rolled steel plate having a thickness of 0.23mm were obtained. Subsequently, to the above cold-rolled steel sheet, after the decarburization annealing under the temperature condition is performed of heating 2 minutes at 800 ° C., annealing separator containing magnesia (MgO) as the main component, It applied to the surface of the cold rolled steel sheet.
[0082]
　Subsequently, with respect to cold-rolled steel sheet annealing separator is applied, final annealing process was performed under the temperature condition of heating at 1200 ° C. 20 hours. As a result, has the chemical composition described above, cold-rolled steel sheet crystal orientation is controlled so that the crystal grains of the easy magnetization axis and the rolling direction coincides (steel sheet glass coating film is formed on the surface) was obtained .
[0083]
　Subsequently, as described above, by the laser is irradiated to the surface of the steel sheet glass coating film is formed on the surface of the steel sheet, a plurality of grooves extending in a direction perpendicular to the rolling direction, along the rolling direction It formed at a predetermined interval Te. As the irradiation conditions of the laser is set laser output is 200 ~ 2000 W, the condensing spot diameter (86% diameter) is set to 10 ~ 1000 .mu.m in the rolling direction of the laser light condensing spot diameter in the sheet width direction of the laser (86 % diameter) is set to 10 ~ 4000 .mu.m, the laser scanning speed is set to 1 ~ 100m / s, the laser scanning pitch is set to 4 ~ 10 mm.
[0084]
　Simultaneously with the laser irradiation, the assist gas is blown to the site of the steel plate the laser is irradiated. So as to satisfy the above conditions 1 and 2, the assist gas injection angle relative to the laser scanning direction (first angle .theta.1), the assist gas injection angle relative to the surface of the steel sheet (second angle .theta.2), and the flow rate of the assist gas is adjusted. Specifically, the first angle θ1 was adjusted in the range of 90 ° or more than 180 °. The second angle θ2 was adjusted in a range of 1 ° or more 85 ° or less. The flow rate of the assist gas was adjusted in a range of min 10 to 1000 liters. Moreover, present in Tsuban atmosphere during laser irradiation, the quantity of particles having a size of at least 0.5μm is performed in an atmosphere controlled so Nau 10000 fewer than 10 or more per 1CF.
[0085]
　As described above, with respect to grooved steel sheet under the temperature condition that the insulating coating solution containing colloidal silica and phosphate is then coated over the glass coating film is heated for 1 minute at 850 ° C. in the heat treatment is performed, and finally, the steel sheet which the grooves are formed, oriented electrical steel sheet with a glass coating film and an insulating film was obtained.
[0086]
　Finally obtained steel sheet of the oriented electrical steel sheet (steel sheet in which grooves are formed) mainly, Si: contained 3.0%.
[0087]
　By the above-described processes, as shown in Table 1, as Examples 1-8, it was prepared oriented electrical steel sheet satisfying the above conditions 1 and 2. Further, as Comparative Examples 1-4, it was prepared oriented electrical steel sheet which does not satisfy at least one of the conditions 1 and 2. As described above, the assist gas injection angle relative to the laser scanning direction (first angle .theta.1), the assist gas injection angle relative to the surface of the steel sheet (second angle .theta.2), the assist gas flow rate, and the amount of particles in Tsuban atmosphere, the a is example those adjusted in the range described in the embodiment, a comparative example that deviate from the scope thereof.
[0088]
　Note that each of the grain-oriented electrical steel sheet that corresponds to Examples 1-8 and Comparative Examples 1-4, was identified groove bottom region of the groove by a specific method described in the above embodiment. The measurement of the surface roughness parameter indicating the surface roughness of the groove bottom region (Ra, RSm), laser type surface roughness measuring device (manufactured by Keyence Corporation of VK-9700) was used. Further, in the verification 1, prior to formation of the insulating film to remove iron-containing particles formed on the surface of the steel sheet by the formation of grooves in brushing.
[0089]
　For each oriented electrical steel sheet that corresponds to Examples 1-8 and Comparative Examples 1-4, it was verified rust resistance. Specifically, a test piece of 30mm square from each oriented electrical steel sheet was taken, the test piece, the test piece is subjected to a temperature of 50 ° C. and a humidity of 91% and allowed to stand for 1 week, the test piece in its longitudinal It was assessed on the basis of the weight change. 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 corresponding to Examples 1-8, by satisfying the conditions 1 and 2 described above (i.e. by adopting the structure A), it was confirmed to be improved rust resistance of the grain-oriented electrical steel sheet.
[0090]
[Table 1]

[0091]
　For reference, the results of measurement of the magnetic characteristics (iron loss W17 / 50) after rust resistance test, the iron loss of Examples 1-8 rust resistance is "good" is from 0.702 to 0. It was 822W / kg. Core loss of Comparative Example 1 rust resistance is "bad" was 0.951W / kg. Also the core loss of Comparative Example 4 rust resistance is "bad" was 0.794W / kg. In Examples 1-8, the particle diameter of the crystal grains in contact with the groove in the steel sheet was 5μm or more. In Examples 1-8 and Comparative Examples 1-4 together, the groove depth D is 5μm or more 40μm or less, the groove width W was 10μm or 250μm or less.
[0092]
[Rust resistance verification 2]
　Subsequently, as shown in Table 2, using a known production method, as in Example 9, to satisfy the above conditions 1 and 2, and directional electromagnetic without a glass coating film It was prepared steel plate. Further, as Comparative Examples 5-7, it does not satisfy the at least one of the conditions 1 and 2 were and prepared oriented electrical steel sheet without a glass coating film. The chemical composition of the steel sheet is the same as the verification 1. Like the verification 1, in order to satisfy the above Conditions 1 and 2, the assist gas injection angle with respect to the laser scanning direction (first angle .theta.1), the assist gas injection angle with respect to the steel sheet surface and the (second angle .theta.2), assisted and the flow rate of the gas 25, the particle amount in the strip passing atmosphere was adjusted within the range described in the above embodiment.
[0093]
　For each corresponding oriented electrical steel sheets in Examples 9 and Comparative Examples 5-7, it was verified rust resistance by using the same verification process as the verification 1. As a result, as shown in Table 2, even oriented electrical steel sheet without a glass coating film, by adopting the structure A satisfying the conditions 1 and 2, it is confirmed that the rust resistance is improved It was.
　For reference, the results of measurement of the magnetic characteristics (iron loss W17 / 50) after rust resistance test, the iron loss of Example 9 rust resistance is "good" was 0.832W / kg . Core loss of Comparative Example 5 rust resistance is "bad" was 0.925W / kg. Also the core loss of Comparative Example 6 rust resistance is "bad" was 0.736W / kg. In Examples 9 and Comparative Examples 5-7 together, the groove depth D is 5μm or more 40μm or less, the groove width W was 10μm or 250μm or less.
[0094]
[Table 2]

[0095]
[Rust resistance verification 3]
　Then, in addition to the above conditions 1 and 2, to verify the rust resistance of the grain-oriented electrical steel sheet that satisfies the conditions 3 and 4 below.
　(Condition 3)
　glass coating film and compared to the average content of Mg in mass fraction contained in the insulating film, the area of the glass coating film and the insulating film in the Mg content satisfies 1.3 times or more the average Mg when defining the concentrated region, when viewing the groove in the groove widthwise cross, the Mg concentrated region is, starting from the boundary between the grooves and the steel sheet surface and perpendicular to the thickness direction at the groove widthwise sectional and it contained away from the groove to 10μm following areas than 0.1 [mu] m.
　(Condition 4)
　when viewing the groove from a thickness direction (if the grooves in plan view), Mizonobe distance dw between the Mg concentrated region adjacent to each other along the extension direction is 0 super 100μm or less.
[0096]
　As shown in Table 3, by the same process as the verification 1, as Examples 10 to 18, satisfies the above conditions 1 and 2, and were prepared oriented electrical steel sheet which satisfies the above conditions 3 and 4. Further, as Examples 19-21, it satisfies the above conditions 1 and 2, and were prepared oriented electrical steel sheet which does not satisfy at least one of the above conditions 3 and 4. Like the verification 1, so as to satisfy the above conditions 1 to 4, the assist gas injection angle with respect to the laser scanning direction (first angle .theta.1), the assist gas injection angle with respect to the steel sheet surface and the (second angle .theta.2), assist gas and flow rate, and the amount of particles in the strip passing atmosphere was adjusted within the range described in the above embodiment.
[0097]
　Incidentally, in the directional electromagnetic steel plates corresponding to Examples 10-21, the arithmetic mean height Ra of 2.1μm in roughness curve forming the contour of the groove bottom region, the roughness curve element forming the contour of the groove bottom region of the groove the average length RSm of was 45 [mu] m. Moreover, in this verification 3, before the formation of the insulating film to remove iron-containing particles formed on the surface of the steel sheet by the formation of grooves in brushing. It was also analyzed for Mg content using EPMA.
[0098]
　For each oriented electrical steel sheet corresponding to Examples 10-21, it was verified rust resistance by using the same verification process as the verification 1. As a result, as shown in Table 3, in addition to the above conditions 1 and 2, by satisfying the above conditions 3 and 4 (i.e. by adopting the structure A and C), rust resistance oriented electrical steel sheet it was confirmed that further improved.
　For reference, the results of measurement of the magnetic characteristics (iron loss W17 / 50) after rust resistance test, the iron loss of the Example 10 rust resistance is "good" was 0.836W / kg . Also, core loss of Example 19 rust resistance is "good" was 0.701W / kg. In Examples 10-21, the groove depth D is 5μm or more 40μm or less, the groove width W was 10μm or 250μm or less.
[0099]
[table 3]

[0100]
[Rust resistance verification 4]
　Subsequently, in addition to the above conditions 1 and 2, to verify the rust resistance of the grain-oriented electrical steel sheet which satisfies the condition 5 and condition 6 below.
　(Condition 5)
　when viewing the groove in the groove widthwise cross-section starting from the boundary between the grooves and the steel sheet surface, the groove widthwise in cross-section perpendicular to the thickness direction and in a direction away from the groove 10μm or 500μm following when a region extending was defined as the particle existence region with a length, an insulating film in the particle existence region comprises iron-containing particles.
　(Condition 6)
　the equivalent circle diameter of the iron-containing particles contained in the insulating film in the particles present region is at 0.1μm or 2μm or less, the ratio of the area of the iron-containing particles to the area of particle existence region of 0.1% or more it is less than 30%.
[0101]
　As shown in Table 4, by the same process as the verification 1, as Examples 22-30, satisfies the above conditions 1 and 2, and were prepared oriented electrical steel sheet which satisfies the above conditions 5 and 6. Further, as Examples 31 to 34, it satisfies the above conditions 1 and 2, and were prepared oriented electrical steel sheet which does not satisfy at least one of the conditions 5 and 6. Like the verification 1, so as to satisfy the above conditions 1, 2, 5 and 6, the assist gas injection angle with respect to the laser scanning direction (first angle .theta.1), the assist gas injection angle relative to the surface of the steel sheet (second angle .theta.2) When the flow rate of the assist gas and the amount of particles in the strip passing atmosphere was adjusted within the range described in the above embodiment.
　Incidentally, in the directional electromagnetic steel plates corresponding to Examples 22-34, the arithmetic mean height Ra of 1.9μm in roughness curve forming the contour of the groove bottom region, the roughness curve element forming the contour of the groove bottom region of the groove the average length RSm of was 42 .mu.m.
[0102]
　For each oriented electrical steel sheet corresponding to Examples 22-34, it was verified rust resistance by using the same verification process as the verification 1. As a result, as shown in Table 4, in addition to the above conditions 1 and 2, by satisfying the above conditions 5 and 6 (i.e. by employing the configuration A and B), rust resistance oriented electrical steel sheet it was confirmed that further improved.
　For reference, the results of measurement of the magnetic characteristics (iron loss W17 / 50) after rust resistance test, the iron loss of the Example 22 rust resistance is "good" was 0.823W / kg . Also, core loss of Example 31 rust resistance is "good" was 0.718W / kg. In Examples 22-34, the groove depth D is 5μm or more 40μm or less, the groove width W was 10μm or 250μm or less.
[0103]
[Table 4]

[0104]
[Verification 5 of rust resistance]
　Subsequently, the three requirements, and in addition to 4 was verified rust resistance of the grain-oriented electrical steel sheet which satisfies the condition 5 and condition 6.
[0105]
　As shown in Table 5, by the same process as the verification 1, as Examples 35-37 satisfies the conditions 1, 2, 3 and 4, and the grain-oriented electrical steel sheet which satisfies the above conditions 5 and 6 It was prepared. Further, as Examples 38-40 satisfies the conditions 3, 4, 5 and 6, and were prepared oriented electrical steel sheet which does not satisfy at least one of the above conditions 1 and 2. Further, as Examples 41 to 43, it satisfies the above conditions 1, 2, 5 and 6, and were prepared oriented electrical steel sheet which does not satisfy at least one of the above conditions 3 and 4. Further, as Examples 44-46 satisfies the conditions 1, 2, 3 and 4, and was prepared oriented electrical steel sheet which does not satisfy at least one of the conditions 5 and 6. Like the verification 1, so as to satisfy the above conditions 1, 2, 3 and 4, the assist gas injection angle with respect to the laser scanning direction (first angle .theta.1), the assist gas injection angle relative to the surface of the steel sheet (second angle .theta.2) When the flow rate of the assist gas and the amount of particles in the strip passing atmosphere was adjusted within the range described in the above embodiment.
[0106]
　For each oriented electrical steel sheet corresponding to Examples 35-46, it was verified rust resistance by using the same verification process as the verification 1. As a result, as shown in Table 5, in addition to the above conditions 1, 2, 3 and 4, by satisfying the conditions 5 and 6 (i.e. configuration A, by employing all B and C), oriented electrical it was confirmed that the rust resistance of the steel sheet is further improved. In Examples 35-46, the groove depth D is 5μm or more 40μm or less, the groove width W was 10μm or 250μm or less.
[0107]
[table 5]

Industrial Applicability
[0108]
　According to this aspect of the present invention, since it is possible to improve the rust resistance of the grain-oriented electrical steel sheet in which the grooves on the surface of the steel sheet is formed for domain refining, industrial applicability sufficient It has to.
DESCRIPTION OF SYMBOLS
[0109]
　1 oriented electrical steel sheet
2 steel
2a steel surface
2b steel region
3 glass coating film
4 insulating film
5 grooves
5a groove bottom region
5b groove region
6 iron-containing particles
BL groove base line
LWC groove longitudinal waviness curve
SWC groove widthwise waviness curve
RC roughness curve
W1 particle existence regions
W2 Mg concentrated region
W groove width
X rolling direction
Y plate width direction
Z thickness direction

The scope of the claims
[Claim 1]
　In grain-oriented electrical steel sheet and the groove depth direction extends in a direction crossing the rolling direction comprises a steel plate having become grooves formed steel surface thickness direction,
　a groove comprising Mizonobe extension direction and the thickness direction if the longitudinal section viewed the grooves,
　the arithmetic mean height Ra of the roughness curve forming the contour of the groove bottom region of the groove is at 1μm or more 3μm or less,
　roughness forming the contour of the groove bottom region average length of profile elements RSm is, it is 10μm or more 150μm or less,
　the grain-oriented electrical steel sheet further comprises an insulating film,
　when viewed with the grooves in the groove widthwise cross section perpendicular to the Mizonobe extension direction,
　said grooves wherein a boundary between the steel sheet surface as a starting point, when defining said groove widthwise sectional in the plate thickness direction perpendicular to and the above 10μm in a direction away from the groove 500μm following areas particle existence region and,
　the particles present said insulating in the region Film includes an iron-containing particle equivalent circle diameter of 0.1μm or more 2μm or less,
　the ratio of the area of the iron-containing particles to an area of the particles existing region is less than 30% 0.1% or more,
　the iron chemical components containing particles comprise a 80 to 100 wt% Fe, and 0-10 wt% of Si, from 0 to 10% by weight and a Mg
-oriented electrical steel sheet, characterized in that.
[Claim 2]
　The oriented electrical steel sheet further comprises a glass coating film between said insulating film and said steel sheet,
　as compared with the average content of Mg in mass fraction contained in the glass film and the insulating film, the Mg content is when the glass coating film and a region in the insulating film satisfies the above 1.3 times the average was defined as Mg concentrated region,
　when viewed with the grooves in the groove widthwise cross section perpendicular to the Mizonobe extension direction,
　the Mg concentrated region, starting from the boundary between the groove and the steel sheet surface, the groove widthwise perpendicular to the thickness direction in cross-section and 10μm following areas direction 0.1μm or more away from the groove included are, and,
　if from the plate thickness direction as viewed the groove,
　the Mg concentrated region is continuously present along the Mizonobe extending direction,
　or, the plurality of the Mg concentrated region there have intervals along the Mizonobe extension direction, before Serial Mizonobe distance between the Mg concentrated region adjacent to each other along the extension direction is greater than 0 100μm or less
oriented electrical steel sheet according to claim 1, characterized in that.
[Claim 3]
　On the groove, the mean and thickness 5μm or less of the glass coating film above 0 .mu.m, the average and the thickness is formed with the insulating film of 1μm or 5μm or less,
　on the steel sheet, an average thickness of more than 0.5μm and following the glass coating film 5 [mu] m, average and thickness are formed with the insulating film of 1μm or 5 [mu] m or less,
　the average thickness of the glass coating film formed on the groove, formed on the steel sheet thinner than the average thickness of the glass coating film
oriented electrical steel sheet according to claim 2, characterized in that.
[Claim 4]
　Oriented electrical steel sheet according to any one of claims 1 to 3 in the steel plate, wherein the grain size of the crystal grains in contact with the groove is 5μm or more.