The present invention, grain-oriented electrical steel sheet used as an iron core material of a transformer, in particular, excellent in adhesion tension insulating coating, to an amorphous oxide film having a directional magnetic steel sheet.
　The present application, to 07 May 13, 2017, claiming priority based on Japanese Patent Application No. 2017-137440, filed in Japan, the contents of which are incorporated here.
BACKGROUND
[0002]
　Oriented electrical steel sheet is mainly used in the transformer. Transformer, a long period of time until it is discarded from the seated, is continuously energized, continues to generate the energy loss. Therefore, the energy loss when magnetized by alternating current, i.e., the iron loss, the main parameters that determine the performance of the transformer.
[0003]
　In order to reduce the iron loss oriented electrical steel sheet, so far, for example, called Goss orientation {110} <001> to increase the integration of the orientation, increasing the content of Si or the like solid solution elements to increase the electrical resistance that, by using a technique such as reducing the thickness of the plate thickness, many developers have been made.
[0004]
　Further, it is effective in reducing the iron loss to impart tension to the steel sheet. In order to impart tension to the steel sheet, the thermal expansion coefficient of the small material of the coating from the steel sheet at a high temperature, it is effective to form on the surface of the steel sheet. In the finish annealing step, forsterite coating and the oxide surface of the steel sheet and annealing separator is produced by the reaction can tension the steel sheet has excellent coating adhesion.
[0005]
　For example, disclosed in Patent Document 1, a method of forming an insulating film by baking a coating solution mainly containing colloidal silica and phosphoric acid salt, a large effect of tensioning to the steel sheet, effective to reduce iron loss it is. Therefore, after leaving the forsterite film generated in the finish annealing step, it is subjected to insulating coating mainly comprising phosphate, and has a production method of common grain-oriented electrical steel sheet.
[0006]
　On the other hand, the domain wall motion is inhibited by the forsterite coating, may adversely affect the iron loss has become clear. In the grain-oriented electrical steel sheet, magnetic domains, under the alternating magnetic field varies with the movement of the domain walls. That the domain wall movement is performed smoothly, it is effective to iron loss improvement. However, forsterite coating is to have an uneven structure in the steel / insulating film interface, the movement of the domain wall is hindered, adversely affects the iron loss.
[0007]
　Therefore, so far, to suppress the formation of forsterite coating, a technique for smoothing the surface of the steel sheet has been developed. For example, Patent Documents 2-5 control the dew point of the decarburization annealing, and by using alumina as an annealing separating agent, without forming a forsterite coating after finish annealing to smooth the surface of the steel sheet technology There has been disclosed.
[0008]
　However, when the smoothed surface of the steel sheet in this manner, in order to impart tension to the steel sheet, the steel sheet surface, it is necessary to form a tension insulating film having a sufficient adhesion.
　For such problems, in Patent Document 6, after forming the amorphous oxide film on the surface of the steel sheet, a method of forming a tension insulating film is disclosed. Patent Document 7 to 11, for the purpose of forming a further high adhesion tension insulating film, a technique for controlling the structure of the amorphous oxide film is disclosed.
[0009]
　Patent Document 7 discloses a method of securing the coating adhesion to the tension insulating film and the steel sheet is disclosed. In this way, the surface of the steel sheet of grain-oriented electrical steel sheet of the steel sheet surface was smoothed, was subjected to a treatment prior to introduction of the fine irregularities, to form external oxidation type oxide, further, the thickness of the external oxide film It has secured coating adhesion by forming a particulate external oxide based on silica penetrating form the.
[0010]
　Patent Document 8, a method of securing the coating adhesion to the tension insulating film and the steel sheet is disclosed. In this way, in the heat treatment process for forming the external oxidation type oxide film to the surface of the steel sheet grain-oriented electrical steel sheet obtained by smoothing, 200 ° C. or higher 1150 ° C. The heating rate of the following temperature range 10 ° C. / sec to 500 ° C. / sec to control the following iron to total external oxide film, aluminum, titanium, manganese, a cross-section area of ​​the metal-based oxide such as chromium by 50% or less, the coating adhesion to the tension insulating film and the steel sheet It has secured sex.
[0011]
　Patent Document 9, a method of securing the coating adhesion to the tension insulating film and the steel sheet is disclosed. In this way, the steel sheet surface to form external oxidation type oxide film on the grain-oriented electrical steel sheet smoothed, in the step of forming the subsequent tension insulating film, an external oxide type oxide film-coated steel sheet and the tension insulating film-forming coating liquid by the contact time to less than 20 seconds and the ratio of the density reduction layer in the outer oxidized oxide film as a 30% or less so as to ensure a coating adhesion to the tension insulating film and the steel sheet.
[0012]
　Patent Document 10, a method of securing the coating adhesion to the tension insulating film and the steel sheet is disclosed. In this method, carried out at a temperature heat treatment of more than 1000 ° C. to form an external oxide type oxide film surface of the steel sheet to a grain-oriented electrical steel sheet obtained by smoothing the temperature of the formation temperature of the external oxide type oxide film to 200 ° C. controlling the cooling rate of the band below 100 ° C. / sec, a cavity in the external oxide type oxide film by 30% or less in the cross-sectional area ratio, to ensure coating adhesion to the tension insulating film and the steel sheet there.
[0013]
　Patent Document 11, a method of securing the coating adhesion to the tension insulating film and the steel sheet is disclosed. In this way, in the heat treatment process for forming the external oxidation type oxide film to the surface of the steel sheet grain-oriented electrical steel sheet obtained by smoothing, the heat treatment temperature 600 ° C. or higher 1150 ° C. or less, the dew point -20 ° C. or higher 0 ℃ less and carried out in conditions and annealed under the conditions that the dew point of the cooling atmosphere at that time with 5 ° C. or higher 60 ° C. or less, 5% or more than 30% of metallic iron in sectional area ratio in the outer oxide type oxide film It is contained so as to ensure the coating adhesion to the tension insulating film and the steel sheet.
[0014]
　However, in the prior art, it can not be obtained sufficient adhesion between the tension insulating film and the steel sheet, when it is difficult to draw a sufficient iron loss reducing effect as expected has occurred.
CITATION
Patent Document
[0015]
Patent Document 1: Japanese Sho 48-039338 Patent Publication
Patent Document 2: Japanese Patent Laid-Open 07-278670 discloses
Patent Document 3: Japanese Patent Laid-Open 11-106827 discloses
Patent Document 4: Japanese Patent 11- 118750 JP
Patent Document 5: Japanese Patent 2003-268450 JP
Patent Document 6: Japanese Patent Laid-Open 07-278833 discloses
Patent Document 7: Japanese Patent 2002-322566 JP
Patent Document 8: Japanese Patent 2002-348643 JP
Patent Document 9: Japanese Patent 2003-293149 JP
Patent Document 10: Japanese Patent 2002-363763 JP
Patent Document 11: Japanese Patent 2003-313644 JP
Non-patent literature
[0016]
Non-Patent Document 1: Vol iron and steel. 77 (1991) No. 7 p. 1075
Summary of the Invention
Problems that the Invention is to Solve
[0017]
　The present invention, light of the prior art, in the grain oriented electrical steel sheet having no forsterite coating, and aims to enhance the coating adhesion to the tension insulating film and the steel sheet surface. That is, the present invention aims to provide a grain-oriented electrical steel sheet excellent in coating adhesion to the tension insulating film and the steel sheet surface.
Means for Solving the Problems
[0018]
　The present inventors have intensively studied a technique for solving the above problems. As a result, after forming the amorphous oxide film on the surface of the steel sheet, when the morphology of the amorphous oxide film in a uniform (smooth), that the coating adhesion to the tension insulating film and the steel sheet surface is improved and knowledge.
[0019]
　The present invention has been made based on the above findings and has as its gist is as follows.
(1) grain-oriented electrical steel sheet according to an embodiment of the present invention includes a steel sheet, and the amorphous oxide film formed on the steel sheet, wherein the steel sheet, as a chemical composition, in mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn: 1.50% or less, acid soluble Al: 0.065% or less, S: 0.013% or less, Cu: 0 ~ 0 .80%, N: 0 ~ 0.012 %, P: 0 ~ 0.50%, Ni: 0 ~ 1.00%, Sn: 0 ~ 0.30%, Sb: 0 ~ 0.30%, the contained, the balance is a value measured by a mapping image clarity measuring device mapping sharpness of the surface of Fe and impurities, NSIC value of the surface is 4.0% or more.
[0020]
(2) oriented electrical steel sheet according to the above (1), the steel sheet, as the chemical composition, by mass%, Cu: may contain 0.01 to 0.80%.
[0021]
(3) above (1) or oriented electrical steel sheet according to (2), the steel sheet, as the chemical composition, in mass%, N: 0.001 ~ 0.012%, P: 0.010 ~ 0.50%, Ni: 0.010 ~ 1.00%, Sn: 0.010 ~ 0.30%, and, Sb: contain one or more 0.010 to 0.30% it may be.
The invention's effect
[0022]
　According to this aspect of the present invention can be oriented electrical steel sheet not forsterite coating is formed on the surface, it provides a significantly higher oriented electrical steel sheet coating adhesion to the tension insulating film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023]
FIG. 1 is a graph showing a relationship between the film remaining area ratios and NSIC value.
DESCRIPTION OF THE INVENTION
[0024]
　Oriented electrical steel sheet according to an embodiment of the present invention (hereinafter sometimes referred to as "electromagnetic steel sheet according to the present embodiment".) Is,
　and the steel plate, and the amorphous oxide film formed on the steel sheet, the has the steel sheet, as a chemical composition, in mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn: 1.50% or less, acid soluble Al: 0.065% hereinafter, S: 0.013% or less, Cu: 0 ~ 0.80%, N: 0 ~ 0.012%, P: 0 ~ 0.50%, Ni: 0 ~ 1.00%, Sn: 0 ~ 0.30%, Sb: 0 ~ 0.30 %, and contains, the balance being Fe and impurities
　are values measured by the mapping image clarity measuring device mapping sharpness of the steel sheet surface, the steel sheet surface NSIC value (value measured by mapping image clarity measuring apparatus [NSIC] mapping sharpness of the steel sheet surface) is 4.0% or more.
　The electromagnetic steel sheet containing, by mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn: 0.01 ~ 1.50%, acid-soluble Al: 0.01 ~ 0.065 % S: it contains 0.003 to 0.013%, and the material of the slab and the balance Fe and impurities, a grain-oriented electrical steel sheet having no forsterite coating.
[0025]
　It described oriented electrical steel sheet according to an embodiment of the present invention (magnetic steel sheet according to the present embodiment).
[0026]
　
　The present inventors have, forsterite no coating (forsterite film on the surface is not formed) in the oriented electrical steel sheet was investigated how to ensure excellent coating adhesion. As a result, it is necessary to suppress the stress concentration at the interface between the coating and the steel sheet surface, So, on the surface of the steel sheet has no forsterite coating, an amorphous oxide film (especially a surface of a steel sheet to in terms of an amorphous oxide film formation) was in direct contact, to be the morphology of the amorphous oxide film in uniform (even) intensive studies conceived to be important. Steel no forsterite coating, or to remove the forsterite coating after finish annealing, or it can be formed by intentionally prevent the formation of forsterite. For example, by adjusting the composition of the annealing separator, it is possible to intentionally prevent the formation of forsterite.
[0027]
　As described above, the surface of the steel sheet has no forsterite coating, after forming the amorphous oxide film, morphology (amorphous oxide of the amorphous oxide of the amorphous oxide film by uniform morphology) of the film, the tension insulating film is further formed thereon, it is considered possible to improve the adhesion between the steel sheet. However, the thickness of the amorphous oxide film very thin and several nm, it is very difficult to evaluate the morphology of the homogeneity of the amorphous oxide film (the smoothness).
[0028]
　The present inventors have intensive studies results, the film morphology of the uniformity of the amorphous oxide film of thickness number nm (smoothness) of the mapping image sharpness degree to evaluate the sharpness of the steel sheet surface (mapping DOI it has been found that can be evaluated by the measuring device measured by [NSIC]).
[0029]
　As means for evaluating the sharpness of the steel sheet surface, although PGD meter is widely known, PGD meter, it has been reported that the sensitivity in the high gloss area drops. Meanwhile, NSIC has high sensitivity in the high gloss area, the measurements are reported to better match the visual evaluation (non-patent document 1, reference).
[0030]
　Hence, the present inventors have found that the film thickness is very thin and a few nm, an index for evaluating the surface of the amorphous oxide film of high gloss, considered towards the NSIC value than PGD value is preferred, NSIC value in, it was decided to evaluate the amorphous oxide film to define.
[0031]
　In the present embodiment, NSIC value is a value measured mapping sharpness degree of the film surface (smoothness) using Suga Tester Co. mapping DOI measuring device (NSIC).
[0032]
　More specifically, between the surface to be measured and the light source, arranged slit plate formed with straight slits, the light from a light source is irradiated to the measured surface through the slit of the slit plate, the imaging device and the surface to be measured in imaging is a value calculated based on the linearity and lightness difference of the slit beam image in the captured image (the difference in brightness of the slit beam image and the background image neighboring thereof). NSIC value is the case where the surface to be measured is black mirror is 100, a value calculated by the relative therewith.
[0033]
　That is, as the NSIC value is high, the morphology of the amorphous oxide film thickness of several nm to coat the steel sheet surface is uniform (even).
　The present inventors have conducted described below experiments were investigated and the film adhesion, the relationship between the NSIC value of the surface of the grain oriented electrical steel sheet having an amorphous oxide.
[0034]
　As experimental materials, including Si 3.4%, the decarburization annealed sheet having a thickness of 0.23 mm, the annealing separator consisting mainly of alumina was applied to the secondary recrystallization performing finish annealing, folders It was prepared oriented electrical steel sheet having no stellite-based film. This grain-oriented electrical steel sheet, 25% of nitrogen, hydrogen 75%, in an atmosphere of a dew point -30 ~ 5 ° C., subjected to a heat treatment of soaking time 10 seconds, the amorphous oxide mainly comprising silica on the surface of the steel sheet the formed.
[0035]
　NSIC value of the surface of the amorphous oxide film with oriented electrical steel sheet (mapping image sharpness degree) was measured using a mapping image clarity measuring apparatus manufactured by Suga Tester Co..
　Then, the surface of the grain-oriented electrical steel sheet having an amorphous oxide film, a phosphate, chromic acid, and a coating liquid composed mainly of colloidal silica was coated, in a nitrogen atmosphere, 30 seconds at 835 ° C., baking, to form a tension insulating film on the surface of the steel sheet was investigated coating adhesion to the steel sheet surface tension insulating coating.
[0036]
　Coating adhesion, the test piece taken from the steel plate forming the tension insulating film, (bend 180 °) wound around the cylinder having a diameter of 20 mm, in a state where the bent back, the tension insulating film is not peeled off from the steel plate, in close contact area ratio of the portion of the still were evaluated by (hereinafter referred to as "film remaining area ratio".). The coating remaining area ratio may be determined visually.
[0037]
　Figure 1 shows the relationship between the coating remaining area ratios and NSIC value.
[0038]
　From Figure 1, the NSIC value is 4.0% or more, the film residual area ratio becomes 80% or more, it can be seen that can ensure good film adhesion. Further, the NSIC value is 4.5% or more, the film residual area ratio is 90% or more can be ensured a better coating adhesion, the NSIC value is 5.0% or more, the film residual area ratio reached 95% or more, it can be seen that can ensure particularly good coating adhesion.
[0039]
　In the electrical steel sheet according to the present embodiment, based on the results shown in FIG. 1, and the steel plate, anda amorphous oxide film formed on the steel sheet surface (if insulation coating is formed to define it NSIC value of the removed surface) (the value measured by mapping image clarity measuring apparatus [NSIC] a mapping image sharpness degree of the steel sheet surface) is 4.0% or more ". The upper limit of the NSIC value is not necessary to define, but not exceed 100.
[0040]
　Here, amorphous and is not made of atoms or molecules regular spatial grid, a solid has a sequence disturbed. More specifically, when subjected to X-ray diffraction, only a halo was detected, indicating the state in which the specific peak is not detected.
　The amorphous oxide film, a film composed of substantially only amorphous oxide. Coating Whether an oxide can be confirmed using TEM and FT-IR.
[0041]
　NSIC value is under the above conditions, if it can be measured using a mapping image clarity measuring apparatus manufactured by Suga Tester Co., tension insulating film on the amorphous oxide film is formed, the tension insulating the test pieces taken from a coated unidirectional electromagnetic steel sheet is immersed in an etching solution of 20% sodium hydroxide 80 ° C. 20 minutes, may be measured NSIC value after selectively removing only the tension insulating film .
[0042]
　Amorphous oxide film is not within oxidized coating, an external oxidation type coating is preferred. Amorphous oxide film of the internal oxidation type, the interface of the steel sheet and the amorphous oxide with a film forms part of the amorphous oxide is recessed, the length in the depth direction of the dimple bets Recessed aspect ratio as the ratio of the length of the base of the join the club is 1.2 or more coatings, the amorphous oxide film of an external oxidation type, the aspect ratio of the coating of less than 1.2.
　Rather than an external oxidation type, to form an amorphous oxide film of the internal oxidation type, there is a case where the tension insulating film is peeled as a starting point the invagination.
[0043]
　Next, a description will be given chemical composition of the electromagnetic steel sheet according to the present embodiment. Hereinafter, the% of the component composition is "% by mass".
[0044]
　
　C: 0.085% or less
　C is an effective element for controlling the primary recrystallization structure is an element to increase the iron loss in the magnetic aging. Therefore, decarburization annealing before finish annealing, it is necessary to reduce the C content to less than 0.010%.
　When C content exceeds 0.085% requires a long time decarburization annealing, since productivity is lowered, C content is at most 0.085%. Preferably 0.070% or less, more preferably 0.050% or less.
　The lower limit is not particularly limited, in terms of stably controlling the primary recrystallization structure, preferably at least 0.050%.
[0045]
　Si: 0.80 ~
　7.00% Si is to increase the electrical resistance of the steel sheet is an element to reduce the iron loss. When Si content is less than 0.80%, it is not sufficiently obtained effect of incorporating. The secondary recrystallization annealing during the phase transformation occurs, it can not be controlled to accurately secondary recrystallization, and the crystal orientation is deteriorated, the magnetic characteristics are deteriorated. Therefore, Si content is 0.80% or more. Preferably 2.50% or more, and more preferably not less than 3.00%.
[0046]
　On the other hand, when the Si content exceeds 7.00%, the steel sheet is embrittled, cold rolling becomes difficult, cracking occurs during rolling. Therefore, Si content is at most 7.00%. Preferably 4.00% or less, and more preferably not more than 3.75%.
[0047]
　Mn: 1.50% or less
　if the Mn content exceeds 1.50%, the phase transformed during the secondary recrystallization annealing, no satisfactory magnetic flux density can not be obtained. Therefore, Mn content is at most 1.50%. Preferably 1.20% or less, more preferably not more than 0.90%.
[0048]
　Meanwhile, Mn is an austenite-promoting elements, raising the specific resistivity of the steel sheet, an element which contributes to the reduction of iron loss. When the Mn content is less than 0.01%, the effect of incorporating is not sufficiently obtained, also, the steel sheet becomes brittle during hot rolling. Therefore, Mn content is less than 0.01%. Preferably 0.05% or more, more preferably 0.10% or more.
[0049]
　Acid-soluble Al: 0.065% or less
　of Al exceeds 0.065% coarse (Al, Si) or N precipitates, (Al, Si) N deposition becomes uneven. As a result, the required secondary recrystallized structure can not be obtained, the magnetic flux density decreases. Therefore, acid-soluble Al content is 0.065% or less. Preferably 0.055% or less, and more preferably not more than 0.045%. Al content may be 0%.
　On the other hand, acid-soluble Al combines with N, is an element which forms a function as an inhibitor (Al, Si) N. Therefore, in the slab used in the manufacturing, the acid-soluble Al is less than 0.010%, a sufficient amount of (Al, Si) N is not formed, is not stable secondary recrystallization. Therefore, acid-soluble Al in the slab to be used in the preparation is preferably set to 0.010% or more, the Al may remain in the steel sheet. The content of acid-soluble Al in the slab is more preferably 0.002% or more, more preferably 0.030% or more.
[0050]
　S: 0.013% or less
　When S content exceeds 0.013% precipitation dispersion of MnS becomes uneven, the required secondary recrystallized structure can not be obtained, the magnetic flux density decreases. Therefore, S is at most 0.013%. Preferably 0.012% or less, more preferably not more than 0.011%.
　Meanwhile, S is, in combination with Mn, is an element forming MnS, which acts as an inhibitor. Therefore, in the slab to be used in the production, preferably to a S content of 0.003% or more, the S may remain in the steel sheet. S content in the slab used for fabrication is more preferably 0.005% or more, further preferably 0.008% or more.
[0051]
　Electromagnetic steel sheet according to the present embodiment, in addition to the above elements, for various properties improved, in addition to the above elements, (a) Cu: 0.01 ~ 0.80%, and / or, (b) N: 0. 001 ~ 0.012%, P: 0.50% or less, Ni: 1.00% or less, Sn: 0.30% or less, and, Sb: containing one or more than 0.30% of it may be. Since they need not necessarily contain the lower limit of the content thereof is 0%.
[0052]
　(a) elemental
　Cu: 0 ~
　0.80% Cu combines with S, is an element which forms a precipitate that acts as an inhibitor. When Cu content is less than 0.01%, the effect is not exhibited sufficiently, Cu is preferably 0.01% or more. More preferably 0.04% or more.
[0053]
　On the other hand, when the Cu content exceeds 0.80% dispersion of precipitates becomes inhomogeneous, since the iron loss reducing effect is saturated, Cu content is preferably 0.80% or less. More preferably 0.60%.
[0054]
　(b) group elements
　N: 0 ~ 0.0120%
　N combines with Al, an element that forms AlN that functions as inhibitor.
[0055]
　When the N content is less than 0.001%, the formation of AlN becomes insufficient, N content is preferably 0.001% or more. More preferably 0.006% or more. Meanwhile, N is the, cold rolling is also an element forming a blister (holes) in the steel sheet. When N content exceeds 0.0120%, the cold rolling, there is a fear of generating blister (holes) in the steel sheet, the N content is preferably 0.012% or less. More preferably not more than 0.009%.
[0056]
　P: 0 ~ 0.50%
　P increases the specific resistance of the steel sheet, an element which contributes to the reduction of iron loss. In terms of obtaining reliably the effect of incorporating the, P content is preferably 0.01% or more.
　On the other hand, if P exceeds 0.50%, the rolling resistance decreases. Therefore, P content is preferably 0.50% or less. More preferably not more than 0.35%. The lower limit includes 0% and to reduce P to less than 0.0005%, the manufacturing cost is greatly increased, practically steel, 0.0005%, which is substantially the lower.
[0057]
　Ni: 0 ~ 1.00% Ni
　is raising the specific resistivity of the steel sheet, contributes to the reduction of iron loss by controlling the metal structure of the hot-rolled steel sheet, which is an element contributing to the improvement of the magnetic properties. The lower limit includes 0%, from the viewpoint of obtaining reliably the effect of incorporating, Ni content is preferably 0.01% or more.
　On the other hand, when the Ni content exceeds 1.00%, unstable proceeded secondary recrystallization, the magnetic characteristics are deteriorated. Therefore, Ni content is preferably 1.00% or less. More preferably not more than 0.35%.
[0058]
　Sn:
　0 ~ 0.30% Sb: 0 ~
　0.30% Sn and Sb segregates at grain boundaries, the finish annealing, the annealing separator agent Al is oxidized by moisture release (in this oxidation, different inhibitor strength at the coil location, an element forming a function of preventing the magnetic characteristics fluctuate) to. The lower limit includes 0%, from the viewpoint of obtaining reliably the effect of incorporating the content of each element is also preferably not less than 0.01%.
　On the other hand, each element also the content thereof exceeds 0.30%, the secondary recrystallization becomes unstable, the magnetic characteristics are deteriorated. Therefore, none of the Sn and Sb preferably 0.30% or less. More preferably, each element also below 0.25%.
[0059]
　Balance excluding the elements of an electromagnetic steel sheet according to the present embodiment is Fe and impurities. Impurities inevitably mixed in steel raw material and / or steel manufacturing process, an element that is allowed in a range that does not inhibit the characteristics of an electromagnetic steel sheet according to the present embodiment.
[0060]
　Electrical steel sheet having the chemical composition described above, for example, as a chemical composition, in mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn: 0.01 ~ 1.50%, acid soluble Al: 0.01 ~ 0.065%, S: 0.003 ~ 0.013%, Cu: 0 ~ 0.80%, N: 0 ~ 0.012%, P: 0 ~ 0.50%, Ni: 0 ~ 1.00%, Sn: 0 ~ 0.30%, Sb: 0 ~ 0.30%, and contains the balance is obtained by manufacturing using a slab consisting of Fe and impurities.
[0061]
　It will now be described preferred manufacturing method of the electromagnetic steel sheet according to the present embodiment.
[0062]
　Was melted and cast in the usual way, subjecting the slab with the required components to the normal hot rolling and hot rolled sheet is wound into a coil. Then, after performing hot-rolled sheet annealing to the hot rolled sheet, one cold rolling, or is subjected to a plurality of cold rolling sandwiching the intermediate annealing, the same thickness of the steel sheet as the final product . Then, subjected to decarburization annealing the steel sheet after cold rolling.
[0063]
　Decarburization annealing is preferably carried out in a wet hydrogen atmosphere. By performing the decarburization annealing in the atmosphere, the C content in the steel sheet, while reducing until no magnetic aging deterioration of the product sheet region, the steel sheet structure can be primary recrystallization. The primary recrystallization is a preparation for the next secondary recrystallization.
　After decarburization annealing, the steel sheet in an ammonia atmosphere annealing, to form an AlN inhibitor in the steel sheet.
[0064]
　Subsequently, a finish annealing at 1100 ℃ or higher. Finish annealing may be performed in a coiled form but, because of the anti-seizing of the steel sheet, the steel sheet surface, Al 2 O 3 carried out after applying an annealing separator composed mainly of.
[0065]
　After finish annealing, by using a scrubber, thereby removing at washing the excess annealing separator, a steel plate, to control the surface state of the steel sheet. If the removal of excess annealing separator, together with the processing by the scrubber, it is preferable to carry out rinsing.
　Scrubber, the SiC and abrasive, the grit is, it is preferable to use those which are 100th to 500 th (JISR6010 in P100-P 500).
　If grit is less than # 100, the surface activity is enhanced by being too sharpener steel sheet surface. As a result, like iron oxide is easily formed, since film adhesion is deteriorated, unfavorably. On the other hand, if the grit is No. 500 than can not be sufficiently removed annealing separating agent, since the film adhesion becomes inferior when forming the insulating film is not preferred.
[0066]
　Then, to form an amorphous oxide film of the steel sheet in a mixed atmosphere of hydrogen and nitrogen annealing, the steel sheet surface. The oxygen partial pressure in the annealing to form an amorphous oxide film (P H2 O / P H2 ) is preferably 0.005 or less, more preferably 0.001 or less. Holding temperature is preferably 600 ~ 1150 ° C., more preferably 700 ~ 900 ° C..
　Oxygen partial pressure (P H2 O / P H2 ) is When it is 0.005 greater, iron oxides other than the amorphous oxide film is also formed, the coating adhesion is reduced. Further, it is less than the holding temperature is 600 ° C., the amorphous oxide is not sufficiently generated. In addition, it is not preferable because the equipment load is higher in 1150 ℃ than.
[0067]
　Amorphous oxide film is not within oxidized coating, an external oxidation type coating is preferred. External oxidation type having an aspect ratio of less than 1.2 amorphous oxide morphology uniformity of the film (smoothness) is to be accomplished by controlling cooling of the annealing, the oxygen partial pressure than 0.005 can.
[0068]
　Thus, it is possible to coat adhesion tension insulating film is good, obtaining grain oriented electrical steel sheet having an amorphous oxide coating.
Example
[0069]
　Next, a description will be given of an embodiment of the present invention, conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the present invention is, in this single condition example the present invention is not limited. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention, it is capable of adopting various conditions.
[0070]
　(Example 1)
　to Table 1 are shown a silicon steel slab of chemical composition (steel No. A ~ F), subjected to hot rolling by heating to respectively 1100 ° C., and hot-rolled steel sheet having a thickness of 2.6 mm.
　After annealed at 1100 ° C. in the hot-rolled steel sheet, and a plurality of cold subjected to rolling final thickness cold rolled steel sheet 0.23mm sandwiching the rolling or intermediate annealing between single cold. Then, the cold-rolled steel sheet was subjected to a decarburization annealing and nitriding annealing.
[0071]
[Table 1-1]

[0072]
[Table 1-2]

[0073]
　Then, an aqueous slurry of an annealing separator composed mainly of alumina was applied, 1200 ° C., and finish-annealed for 20 hours to complete the secondary recrystallization, there is no forsterite coating, having a specular gloss, directional It was produced electromagnetic steel sheet. Before finish annealing was carried out to control the removal and surface conditions of the annealing separator by grit of the scrubber shown in Table 2. Analysis of the components of the steel sheet after final annealing were as shown in Table 1-2.
[0074]
　The above steel sheet, 25% nitrogen, consist of hydrogen 75%, in an atmosphere of an oxygen partial pressure shown in Table 2, 800 ° C., subjected to soaking treatment for 30 seconds, then, becomes 25% of nitrogen, hydrogen 75%, Table at an oxygen partial pressure shown in 2, it was cooled to room temperature. If the holding temperature of annealing was 600 ° C. or higher, the coating is formed on the surface of the steel sheet.
[0075]
　Film formed on the surface of the steel sheet is whether an even amorphous oxide film, X-rays diffraction and was confirmed using TEM. In addition, confirmation was also carried out using FT-IR together.
　Specifically, each of the steel coating formed No. Manufacturing conditions No. In combination, a steel sectional processed FIB (Focused Ion Beam), observing the range of 10 [mu] m × 10 [mu] m at a transmission electron microscope (TEM), coating SiO 2 was confirmed to consist of.
　Furthermore, analysis of the surface with Fourier transform infrared spectroscopy (FT-IR), the wave number 1250 (cm -1 peak is present at the position of). This peak, SiO 2 since the peak derived, from this, the film is SiO 2 was confirmed to have been formed by.
　Further, with respect to steel sheet with a coating, when subjected to X-ray diffraction, only a halo was detected except the peak of the base steel, a particular peak is not detected.
　That is, both formed film was an amorphous oxide coating.
[0076]
　Next, to evaluate the adhesion of the tension insulating film, the amorphous oxide film formed was oriented electrical steel sheet, aluminum phosphate, the tension insulating film forming liquid comprising a chromic acid and colloidal silica was applied, 30 seconds at 850 ° C., to produce a tension insulating film having a directional magnetic steel sheet and baked.
[0077]
　It was taken from the manufactured tension insulating film having a directional magnetic steel sheet test piece wrapped cylinder having a diameter of 20 mm (bent 180 °), with a coating residual area ratio when bent back, were evaluated coating adhesion tension insulating coating . Evaluation of coating adhesion tension insulating coating was determine the presence or absence of peeling of the tension insulating film visually. Not peeled off from the steel plate, the coating remaining area ratio was NG of less than less than 90% more than 90% GOOD, 80% or more OK, 80%.
[0078]
　Next, in order to measure the NSIC value of the amorphous oxide film with oriented electrical steel sheet, a test piece taken from one direction electrical steel sheet with tension insulating film, the etching solution of 20% sodium hydroxide 80 ° C. 20 immersed in minutes to selectively remove only the tension insulating film.
[0079]
　The NSIC value of the surface of the amorphous oxide film with oriented electrical steel sheet to selectively remove the tension insulating film was measured using a mapping image clarity measuring apparatus manufactured by Suga Tester Co.. More specifically, between the surface to be measured and the light source, arranged slit plate formed with straight slits, the light from a light source is irradiated to the measured surface through the slit of the slit plate, the imaging device and the surface to be measured in imaging, computed on the basis of the linearity and lightness difference of the slit beam image in the captured image (the difference in brightness of the slit beam image and the background image neighboring thereof). NSIC value is the case where the surface to be measured is black mirror is 100, calculated in the relative therewith. Table 2 shows the evaluation of the coating adhesion to the NSIC value and the tension insulating film.
[0080]
[Table 2]

[0081]
　From Table 2, the NSIC value is 4.0%, it can be seen that the coating adhesion is good.
Industrial Applicability
[0082]
　As described above, according to the present invention, there is provided a grain-oriented electrical steel sheet having no forsterite coating, significantly higher coating adhesion to the tension insulating film, providing an amorphous oxide film having a directional magnetic steel sheet can do. Accordingly, the present invention has high applicability in the electromagnetic steel sheet manufacturing industry and electrical steel sheet processing industry.

WE claims

[Requested item 1]
And the steel sheet,
and the amorphous oxide film formed on the steel sheet,
　has,
　　the steel plate, as a chemical composition, in
　　　mass%, C: 0.085% or
　　　less, Si: 0.80 ~ 7.
　　　00%, Mn: 1.50% or less,
　　　acid soluble Al: 0.065% or
　　　less, S: 0.013% or
　　　less,
　　 Cu: 0 ~ 0.80%, N: 0 ~
　　 0.012%, P: 0
　　 0.50%

　　 Sn:~, 0 ~ 0.30%, Sb: 0 ~ 0.30%,
　and contains,
　　　made balance being Fe and impurities
　mapping distinctness of the surface which is a value measured by mapping image clarity measuring device, NSIC value of the surface is 4.0% or more
and wherein the
grain-oriented electrical steel sheet.
[Requested item 2]
　Said steel sheet, as the chemical composition, by mass%, Cu: oriented electrical steel sheet according to claim 1, characterized in that it contains 0.01 to 0.80%.
[Requested item 3]
　Said steel sheet, as the chemical composition, in mass%, N: 0.001 ~ 0.012%, P: 0.010 ~ 0.50%, Ni: 0.010 ~ 1.00%, Sn: 0. from 010 to 0.30%, and, Sb: 0.010 oriented electrical steel sheet according to claim 1 or 2, characterized in that it contains - one or more 0.30% of.