The present invention is oriented electrical steel sheet used as an iron core material of a transformer, in particular, coating adhesion about excellent grain-oriented electrical steel sheet.
　The present application, to 07 May 13, 2017, claiming priority based on Japanese Patent Application No. 2017-137433, filed in Japan, the contents of which are incorporated here.
BACKGROUND
[0002]
　Oriented electrical steel sheet is used mainly transformer. Transformer is continuously energized for a long time before it is discarded from the seated decision since the energy losses continue to occur, the energy loss when magnetized by alternating current, i.e., core loss performance of the transformer become a major parameters to be.
[0003]
　In order to reduce the iron loss oriented electrical steel sheets used in transformers, ever, many developers have been made. For example, increasing the accumulation of the {110} <001> orientation called Goss orientation, increasing the content of Si or the like solid solution elements to increase the electrical resistance, it is possible such as to thin the thickness. Further, it is known that applying a tension to the steel sheet is effective in reducing the iron loss.
[0004]
　In order to impart tension to the steel sheet, it is effective to form on the steel plate a coating consisting of a small material having thermal expansion coefficient than steel at high temperatures. Forsterite film oxide surface of the steel sheet at the finish annealing step and the annealing separator is produced by the reaction can tension the steel sheet, adhesion to the steel plate (coating adhesion) are also excellent.
[0005]
　Patent Document 1, a method of forming an insulating film by baking a coating solution mainly comprising colloidal silica and phosphate is disclosed. This method has a large effect of tensioning to the steel sheet is effective in reducing iron loss. Therefore, after leaving the forsterite film generated by such a finish annealing step, a method of applying an insulating coating mainly composed of phosphate, and has a production method of common grain-oriented electrical steel sheet.
[0006]
　On the other hand, in recent years, forsterite coating inhibits the domain wall motion, it has become clear that an adverse effect on the iron loss. 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, since the forsterite coating has an uneven structure on the steel sheet / insulation coating interface, the movement of the domain wall is hindered, adversely affects the iron loss.
　For such problems, hitherto, to suppress the formation of forsterite coating, a technique for smoothing the surface of the steel sheet have been proposed.
[0007]
　For example, Patent Documents 2-5 control the dew point of the decarburization annealing, by using alumina as an annealing separating agent, without forming a forsterite coating after finish annealing, a technique for smoothing the surface of the steel sheet It has been disclosed.
[0008]
　However, in the case of smoothing the surface of the steel sheet in this manner, in order to impart tension to the steel sheet, it is necessary to form an insulating film having a sufficient adhesion to the steel sheet surface. As a method of forming a tension insulating film having a sufficient adhesion, for example, 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, after performing a process before introducing fine unevenness, by forming the external oxidation type oxide, the film of the outer oxide layer the thickness of silica to form a particulate external oxide based on at penetrating form, and has secured coating adhesion to the tension insulating film and the steel sheet.
[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 step of forming an external oxidation type oxide film to the surface of the steel sheet grain-oriented electrical steel sheet is smoothed, the heating rate of 200 ° C. or higher 1150 ° C. or less of the temperature range 10 ° C. / sec or higher 500 ° C. / sec and controls below and iron occupy the outer oxide layer, aluminum, titanium, manganese, coating adhesion to the tension insulating film and the steel sheet in the cross-sectional area ratio of metallic oxides such as chromium be 50% or less It is secured.
[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 obtained by smoothing, followed, in the step of forming a tension insulating film, coating a tension insulating film formed external oxide type oxide film-coated steel sheet by the contact time between the liquid below 20 seconds, 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, the heat treatment for forming the external oxidation type oxide film to the surface of the steel sheet grain-oriented electrical steel sheet obtained by smoothing performed at 1000 ° C. or higher, the temperature range of from the formation temperature of the external oxide type oxide film to 200 ° C. controlling the cooling rate below 100 ° C. / sec, the cavity in the external oxide type oxide film by 30% or less in cross-section area ratio so as to ensure a coating adhesion to the tension insulating film and the steel sheet.
[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 step of forming an external oxidation type oxide film to the surface of the steel sheet grain-oriented electrical steel sheet obtained by smoothing, heat treated, 600 ° C. or higher 1150 ° C. or less of the temperature range and dew point -20 ° C. or higher 0 ℃ performed under the following conditions, the cooling after the heat treatment is performed in an atmosphere dew point 5 ° C. or higher 60 ° C. the following conditions, by containing 5% to 30% or less of the metal iron sectional area ratio in the outer oxide type oxide film , it has secured coating adhesion to the tension insulating film and the steel sheet.
[0014]
　However, in prior art described above, to draw a sufficient coating adhesion to the expected has occurred can be difficult.
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
Summary of the Invention
Problems that the Invention is to Solve
[0016]
　In view of the state of the prior art, in the grain-oriented electrical steel sheet of the steel sheet surface was smoothed without forming a forsterite film, it is an object to improve the coating adhesion tension insulating coating. That is, the present invention aims to provide a grain-oriented electrical steel sheet excellent in coating adhesion tension insulating coating.
Means for Solving the Problems
[0017]
　The present inventors have intensively studied a technique for solving the above problems. As a result, the oxide film on the steel sheet surface, in the grain oriented electrical steel sheet having a tensile insulation coating containing chromium compounds, if appropriate the amount of Fe in the tension insulating film, increasing the film adhesion tension insulating coating it has been found that it is possible. The present invention has been made based on the above findings and has as its gist is as follows.
[0018]
(1) oriented electrical steel sheet according to an embodiment of the present invention, and the steel plate, SiO is formed on the steel plate 2 and the oxide film containing a tension insulating film formed on the oxide on the film, the a, the steel sheet, as a chemical composition, in mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn: 1.00% 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%, wherein the and the balance Fe and impurities, wherein the tension insulating film comprises a chromium compound, Fe amount of the oxide film and the tension insulating in coating 70 mg / m 2 or more, 250 mg / m 2 or less.
[0019]
(2) oriented electrical steel sheet according to the above (1), the chemical composition of the steel sheet contains, by mass%, Cu: may contain from 0.01 to 0.80%.
The invention's effect
[0020]
　According to this aspect of the present invention, the forsterite film to have not steel sheet surface is the surface of the smoothed-oriented electrical steel sheet, the coating adhesion through the oxide coating is markedly superior tension insulating coating it can be formed. That is, it is possible to provide a grain-oriented electrical steel sheet excellent in coating adhesion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
It is a diagram showing a relationship between Fig. 1] Fe amount of tension insulating film and the oxide film and the film residual rate.
Is a diagram showing the relationship between FIG. 2] Fe content and interlayer current tension insulating film and the oxide film.
DESCRIPTION OF THE INVENTION
[0022]
　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".) It is, and the steel plate, SiO is formed on the steel plate 2 and the oxide film containing, anda tension insulating film formed on the oxide on the film, the steel sheet, as a chemical composition, in mass%, C: 0.085% or less, Si: 0.80 ~ 7.00%, Mn : 1.00% 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%, wherein the and the balance Fe and impurities, wherein the tension insulating film comprises a chromium compound, wherein Fe of the oxide film and the tension insulating in the coating is 70 mg / m 2 or more, 250 mg / m 2 or less
[0023]
　The following describes an electromagnetic steel sheet according to the present embodiment.
[0024]
　
　The present inventors have no forsterite film, when forming a tension insulating film surface of the steel sheet on the surface of the smoothed-oriented electrical steel sheet, ensure excellent coating adhesion to, in baking process of the tension insulating film, which contributes as an adhesion layer responsible for adhesion of the steel sheet and the tension insulating film, SiO 2 oxide film containing, in particular SiO amorphous 2 coating comprising, more preferably substantially amorphous SiO 2 thereby forming a film made of is considered important. 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 oriented electrical steel sheet according to the present embodiment, the oxide coating is substantially amorphous SiO 2 is preferably composed only.
[0025]
　When forming the internal oxide type amorphous oxide, tension insulating coating is peeled off by the forming portion as the starting point. Therefore, the morphology of the amorphous oxide, an external oxidation type are preferred. The internal oxidation type amorphous oxide at the interface of the steel sheet and the amorphous oxide is an oxide form amorphous oxide is recessed, the length in the depth direction of the dimple and the dimple aspect ratio as the ratio of the length of the base is what 1.2 or more is defined as an amorphous oxide of internal oxidation type.
[0026]
　Further, the amorphous SiO as a coating 2 with to the form, amorphous SiO 2 Fe originally present in the formation region of, diffuses into the tension insulating film. Therefore, we thought to be important to optimize the amount of Fe oxide film and tension insulating coating was repeated further investigation by experiments described below.
[0027]
　The electromagnetic steel sheet according to the present embodiment, the steel plate (the base steel sheet) other than the site, i.e., the oxide film (amorphous SiO 2 the amount of Fe contained in the both sites of) and tension insulating film simply tension sometimes referred to as Fe amount in the insulating film.
[0028]
　As test materials, the decarburization annealed sheet having a thickness of 0.23mm containing 3.4% of Si, perform finish annealing by applying an annealing separator consisting mainly of alumina, were secondary recrystallization, forsterite coating was prepared not oriented electrical steel sheet.
[0029]
　This grain-oriented electrical steel sheet, 25% of nitrogen, hydrogen 75%, in an atmosphere of a dew point -30 ° C. ~ 5 ° C., subjected to a heat treatment of soaking time 10 seconds, the steel sheet surface, silica (SiO 2 film to make) mainly It was formed.
　The SiO 2 on the surface of the steel sheet having an oxide coating comprising (specifically, the surface of the oxide film), a phosphate, chromic acid, a coating solution composed mainly of colloidal silica was coated, nitrogen 3-97 % of hydrogen 3-97%, in an atmosphere of a dew point -30 ~ 30 ° C., and baked for 100 seconds at 850 ° C. to form a tension insulating film containing chromium compounds were investigated coating adhesion coating film.
　Since the corrosion resistance is greatly reduced when a chromium-free compound, in the electromagnetic steel sheet according to the present embodiment, the tension insulating film was a tension insulating film containing chromium compound. Chromium compounds include, but its effect can be obtained if it contains little, 1.0 g / m 2 is preferably at least.
[0030]
　Coating adhesion, the test piece taken from the steel sheet, after winding into a cylindrical diameter 30 mm (180 ° bending), when rewinding, without peeling off from the steel plate, the area ratio of the coating remains adhered to the steel plate (hereinafter " was evaluated by sometimes referred film residual ratio ".).
[0031]
　Next, by immersing the steel plate with a bromine methanol solution by dissolving the base material steel plate, to recover the residue was recovered oxide coating and tension insulating coating. The recovered residue was dissolved in perchloric acid and nitric acid, the amount of Fe dissolved solution was analyzed by ICP (Inductively Coupled Plasma) high-frequency inductively coupled plasma emission spectroscopy. The residue that could not be fully dissolved, further dissolved in hydrochloric acid and analyzed for Fe content by ICP.
[0032]
　The relationship between the Fe content and the film remaining ratio of the oxide film and the tension insulating film was analyzed by an ICP shown in FIG. From Figure 1, in order to ensure the film residual rate of 80% or more, Fe amount 250 mg / m 2 must be less than or equal to, in order to secure the coating residual rate of 90% or more, Fe amount 200 mg / m 2 it can be seen that it is necessary to below.
[0033]
　The present inventors have further to confirm the insulation of the tension insulating film, and investigated the relationship between the Fe content and the interlayer current of the oxide film and the tension insulating film. Interlayer current was measured by the method according to JIS C 2550.
[0034]
　Figure 2 shows the measurement results. From Figure 2 two, Fe of the oxide film and the tension insulating film is 70 mg / m 2 is less than, greater than the inter-layer current 300 mA, it can be seen that the insulation is insufficient. Further, Fe of the oxide film and the tension insulating film is 150 mg / m 2 when is more, the interlayer current is less than 50 mA, it can be seen that can ensure good insulation properties. Fe of the oxide film and the tension insulating film is 70 mg / m 2 by weight, it was found also turned black steel plate surface.
[0035]
　Causes blackening of lack of insulation and steel sheet surface is not clear, the baking conditions, the compounds of the conductive iron and phosphorus and is believed to be due to generation. Accordingly, the tension insulating film, in order to ensure the adhesion to the insulating properties, the amount of Fe oxide film and tension insulating coating 70 mg / m 2 or more, 250 mg / m 2 should be less than or equal to. Preferably 150 mg / m 2 or more, 200 mg / m 2 or less.
[0036]
　In tension insulating film and the oxide film, SiO of Si 2 adhesion amount in terms of, preferably less than 50% of the total coating weight. SiO of Si 2 adhesion amount in terms of, if it is the total adhesion amount of 50% or more, the film tension becomes too high, adhesion of the coating may decrease.
　In the insulating film and the oxide film, SiO of Si 2 adhesion amount in terms of in the same manner as the measurement of the amount of Fe described above, it can be obtained by ICP (Inductively Coupled Plasma) high-frequency inductively coupled plasma emission spectroscopy.
　Compared to the tension insulating film, the oxide film is so thin (to several nm), the insulating film and the oxide film, the amount of Fe and, SiO of Si 2 adhesion amount in terms of, in the insulating film, the Fe content and Si SiO 2 is close to the amount deposited in the conversion.
[0037]
　
　Next, a description will be given chemical composition of the electromagnetic steel sheet according to the present embodiment (the component composition). Hereinafter,% of the chemical composition means mass%.
[0038]
　C: 0.085% or less
　C is an element significantly increase the core loss by magnetic aging. When C content exceeds 0.085%, the increase in the iron loss becomes remarkable, C content is at most 0.085%. The content is preferably 0.010% or less, more preferably 0.005% or less. C is more minor, since preferred for reducing the iron loss, the lower limit is not particularly limited, since the order of 0.0001% is a detection limit of 0.0001% are substantially the lower.
[0039]
　Si: 0.80 ~
　7.00% Si controls the secondary recrystallization in secondary recrystallization annealing, an element which contributes to the improvement of the magnetic properties. When Si content is less than 0.80%, the steel sheet is transformed phase in the secondary recrystallization annealing, it is difficult to control the secondary recrystallization, is not good magnetic flux density and iron loss characteristics can not be obtained . Therefore, Si content is 0.80% or more. Preferably 2.50% or more, more preferably 3.00%.
[0040]
　On the other hand, when the Si content exceeds 7.00%, the steel sheet is embrittled, sheet passing property in the manufacturing process is significantly deteriorated. Therefore, Si content is at most 7.00%. Preferably 4.00% or less, and more preferably not more than 3.75%.
[0041]
　Mn: 1.00% or less
　Mn content exceeds 1.00%, the steel sheet is transformed phase in the secondary recrystallization annealing, no satisfactory magnetic flux density and core loss characteristics. Therefore, Mn content is at most 1.00%. Preferably 0.70% or less, more preferably 0.50% or less.
[0042]
　Meanwhile, Mn is an austenite forming element, to control the secondary recrystallization in secondary recrystallization annealing, an element which contributes to the improvement of the magnetic properties. When the Mn content is less than 0.01%, the steel sheet becomes brittle during hot rolling. Therefore, Mn content is preferably 0.01% or more. Mn content is more preferably 0.05% or more, further preferably 0.10% or more.
[0043]
　Acid-soluble Al: 0.065% or less
　When the acid-soluble Al content exceeds 0.065%, AlN precipitation becomes uneven, can not be obtained the required secondary recrystallized structure, magnetic flux density decreases, In addition, the steel sheet becomes brittle. Therefore, acid-soluble Al content is 0.065% or less. Preferably 0.060% or less, more preferably 0.050% or less.
[0044]
　On the other hand, acid-soluble Al combines with N, is an element that generates functions as an inhibitor (Al, Si) N. When the acid-soluble Al content is less than 0.010%, the less AlN generation amount but also the secondary recrystallization may not proceed sufficiently, acid-soluble Al content be 0.010% or more It is preferred. More preferably 0.015% or more, further preferably 0.020% or more.
[0045]
　S: 0.013% or less
　S combines with Mn, is an element forming MnS, which acts as an inhibitor. When S content exceeds 0.013% fine sulfide is formed and iron loss is reduced. Therefore, S content is at most 0.013%. Preferably 0.010% or less, more preferably 0.007% or less.
[0046]
　Since S is preferably as small amounts, the lower limit is not particularly limited, since the order of 0.0001% is a detection limit of 0.0001% are substantially the lower. In that the required amount of forms MnS which functions as an inhibitor, S content is preferably 0.003% or more, more preferably 0.005% or more.
[0047]
　Chemical composition of the electromagnetic steel sheet according to the present embodiment, in addition to the above elements, improve characteristics, may include 0.01 to 0.80% of Cu. Further, within a range that does not impair the properties of the electrical steel sheet according to the present embodiment, N: 0.001 ~ 0.012%, P: 0.50% or less, Ni: 1.00% or less, Sn: 0.30% hereinafter, Sb: it may contain one or more than 0.30% of the. However, since it is not always necessary to contain the lower limit of these elements is 0%.
[0048]
　Cu: 0 ~
　0.80% Cu combines with S, is an element which forms a CuS functioning as an inhibitor. When Cu content is less than 0.01%, the effect is not exhibited sufficiently, the Cu content is 0.01% or more. Preferably 0.04% or more, more preferably 0.07% or more.
[0049]
　On the other hand, when the Cu content exceeds 0.80% dispersion of precipitates becomes inhomogeneous, the iron loss reducing effect is saturated. Therefore, Cu content is made 0.80%. Preferably 0.60% or less, more preferably 0.45% or less.
[0050]
　N: 0 ~ 0.012%
　N combines with Al, an element that forms AlN that functions as inhibitor. 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.
[0051]
　Meanwhile, N is the, cold rolling is also an element forming a blister (holes) in the steel sheet. If N exceeds 0.012% during cold rolling, there is a risk of generating blister (holes) in the steel sheet. Therefore, N content is preferably 0.012% or less. More preferably not more than 0.010%.
[0052]
　P: 0 ~ 0.50%
　P is raising the specific resistivity of the steel sheet, an element which contributes to the reduction of iron loss. The lower limit includes 0%, from the viewpoint of obtaining reliably effect, preferably not less than 0.02%.
　On the other hand, when the P content exceeds 0.50%, the rolling resistance decreases. Therefore, P content is preferably 0.50% or less. More preferably not more than 0.35%.
[0053]
　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 effect, Ni content is preferably 0.02% or more. When Ni content exceeds 1.00%, since the secondary recrystallization proceeds unstable, Ni is preferably 1.00% or less. More preferably not more than 0.75%.
[0054]
　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 effect, each element also content preferably set to 0.02% or more.
[0055]
　On the other hand, when any of the elements also exceeds 0.30%, the secondary recrystallization becomes unstable, the magnetic characteristics are deteriorated. Therefore, both the content of Sn and Sb is preferably 0.30% or less. More preferably, each element also below 0.25%.
[0056]
　The electromagnetic steel sheet according to the present embodiment, the balance excluding the element is Fe and impurities. Impurity is an element mixed in inevitably in steel and / or in the steelmaking process from the steel material.
[0057]
　
　Next, a method for manufacturing the electrical steel sheet according to the present embodiment.
[0058]
　The molten steel having the required chemical composition, were cast in a conventional manner, the slab was subjected to ordinary hot rolling, the hot rolled steel sheet (material of the grain-oriented electrical steel sheet). Then, after performing hot-rolled sheet annealing to the hot-rolled steel 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 the cold rolling.
[0059]
　In the decarburization annealing, it is preferable to heat in a wet hydrogen atmosphere. The heat treatment by the atmosphere, the C content in the steel sheet, reducing the product sheet before the area is no deterioration of the magnetic characteristics due to magnetic aging, at the same time, it is possible to the steel sheet structure is primary recrystallization. This primary recrystallization, the preparation of secondary recrystallization.
[0060]
　After decarburization annealing, then annealed steel sheet in an ammonia atmosphere, to produce an AlN inhibitor.
[0061]
　Subsequently, a finish annealing at 1100 ℃ or higher. Finish annealing is a steel sheet surface, the purpose of anti-seizing of the steel plate, Al 2 O 3 was coated with an annealing separator mainly comprised of, performed in the form of a wound coil of steel sheet.
　After finish annealing, by using a scrubber, to remove the excess annealing separator, and controlling 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 is preferably reduction ratio of the brush is controlled to be 1.0 mm ~ 5.0 mm.
　Undesirable reduction ratio of the brush is less than 1.0 mm, it is impossible to sufficiently remove excess annealing separator, since film adhesion is deteriorated. Also, increased surface activity reduction amount of the brush is scraped more than necessary the surface of the steel sheet becomes a 5.0mm greater than the amount of elution of iron becomes excessive, Fe content in the coating becomes excessive, the coating adhesion since the decrease, which is not preferable.
[0062]
　Then formed annealing, the oxide film in a mixed atmosphere of hydrogen and nitrogen. Oxygen partial pressure of the vapor mixed atmosphere to form an oxide film (P H2 O / P H2 ) is preferably 0.005 or less, more preferably 0.001 or less. Further, the holding temperature is preferably 600 ~ 1150 ° C., more preferably 700 ~ 900 ° C.. If this condition, the amorphous SiO 2 oxide film containing is formed.
　The oxygen partial pressure of 0.005 greater, iron oxides other than the amorphous oxide film is also formed, the coating adhesion is reduced. To become. 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.
[0063]
　The morphology of the oxide film, if the aspect ratio is controlled to an external oxidation type less than 1.2, the annealing for forming an oxide coating, it is preferable to set the oxygen partial pressure during cooling with 0.005 or less .
[0064]
　The oxide coating formed steel plates, aluminum phosphate, chromic acid, and the tension insulating film consisting of colloidal silica was coated, nitrogen 3-97%, of hydrogen 3-97%, the oxygen partial pressure 0.0005-1. of 46 atmosphere, by baking 20 to 100 seconds at 835 ~ 870 ° C., it can be magnetic properties give (electromagnetic steel sheet according to the present embodiment) good oriented electrical steel sheet.
Example
[0065]
　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.
[0066]
　
　were subjected to hot rolling by heating silicon steel compositions shown in Table 1 to 1100 ° C., and hot-rolled steel sheet having a thickness of 2.6 mm. This was subjected to annealing at 1100 ° C. in a hot-rolled steel sheet and a single cold rolling or a plurality of times of cold subjected to rolling cold-rolled steel sheet of the final sheet thickness 0.23mm sandwiching the intermediate annealing.
[0067]
[Table 1]

[0068]
　The above cold-rolled steel sheet was subjected to decarburization annealing and nitriding annealing. It was then coated with a water slurry of the annealing separator consisting mainly of alumina. Then, 1200 ° C., subjected to finish annealing of 20 hours, no forsterite film to obtain a completed oriented electrical steel sheet of the secondary recrystallization having a specular gloss.
[0069]
　This steel sheet, 25% of nitrogen, hydrogen 75%, in an atmosphere of an oxygen partial pressure shown in Table 2, was subjected to soaking treatment for 30 seconds at 800 ° C., 25% nitrogen, hydrogen 75%, the oxygen partial shown in Table 2 It was cooled to room temperature in an atmosphere of pressure. If the holding temperature of annealing was 600 ° C. or higher, the coating is formed on the surface of the steel sheet.
[0070]
　This formed film is, 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. Even in combination, the steel sheet cross-section is processed FIB (Focused Ion Beam), was observed range of 10 [mu] m × 10 [mu] m with a transmission electron microscope (TEM). As a result, coating SiO 2 was confirmed that consist. 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 coating, SiO 2 was amorphous oxide film composed of.
[0071]
　Oriented electrical steel sheet having an amorphous oxide film, aluminum phosphate, the tension insulating film forming liquid comprising a chromic acid and colloidal silica was applied, nitrogen 10-30%, hydrogen 70-90%, Table 2 oxygen partial pressure atmosphere shown, baking temperature shown in Table 2, baked at baking time, to form a tension insulating film.
　Further, by adjusting the mixing ratio of the coating solution, SiO of Si in the tension insulating film 2 the adhesion amount in terms it was less than 50% of the total coating weight.
[0072]
　Tension insulating coating to the specimen from the formed oriented electrical steel sheet harvested, wrapped cylinder having a diameter of 30 mm (bent 180 °), to evaluate the adhesion of the insulating coating with a coating residual rate when bent back. Evaluation of adhesion of the insulation coating was determined whether the release of the tension insulating film visually. Not peeled off from the steel plate, the film residual ratio was NG of less than less than 90% more than 90% GOOD, 80% or more OK, 80%.
[0073]
　Next, in order to measure the amount of Fe tension insulating film and the oxide film, by immersing the steel sheet in bromine methanol solution, by dissolving the base steel was recovered residue. The recovered residue was dissolved in perchloric acid and nitric acid, the amount of Fe dissolved solution was analyzed by ICP. Note that could not be fully dissolved residue is further dissolved in hydrochloric acid and analyzed for Fe content by ICP. The evaluation of the adhesion between the Fe content and the insulating film shown in Table 2.
[0074]
　In addition, to measure the inter-current in accordance with JIS C 2550. The interlayer current shown in Table 2.
[0075]
[Table 2]

Industrial Applicability
[0076]
　As described above, according to the present invention, there is no forsterite coating, the steel sheet surface to the surface of the smoothed-oriented electrical steel sheet, it is possible to coat adhesion is formed significantly superior tension insulating coating, it is possible to provide a superior tension insulating film having a directional magnetic steel sheet in the coating adhesion. Accordingly, the present invention has high applicability in the electromagnetic steel sheet manufacturing industry.

WE claims

[Requested item 1]
　And the steel sheet,
　SiO is formed on the steel plate 2 and the oxide film containing,
　a tension insulating film formed on said oxide on film
have,
　the steel plate, as a chemical composition, in mass%,
　　C : 0.085% or
　　less, Si: 0.80
　　~ 7.00%, Mn: 1.00% 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%,
include ,
　　and the balance Fe and impurities,
　wherein the tension insulating film comprises a chromium compound,
　Fe amount of the oxide film and the tension insulating in the coating is 70 mg / m 2 or more, 250 mg / m 2 or less
and wherein the oriented electrical steel sheet to be.
[Requested item 2]
　Wherein the chemical composition of the steel sheet, by mass%, Cu: oriented electrical steel sheet according to claim 1, characterized in that it comprises 0.01 to 0.80%.