The present invention relates to a grain-oriented electrical steel sheet, in particular, it relates to oriented electrical steel sheet having an insulation coating containing no chromium. This application, on October 31, 2016, claiming priority on Japanese Patent Application No. 2016-213783 filed in Japan, the contents of which are incorporated herein.
BACKGROUND
[0002]
　The grain-oriented electrical steel sheet, on the surface thereof, may have an insulating coating of forsterite layer and a phosphate coating layer. Forsterite layer, after the slab hot rolled to a hot rolled steel sheet, cold rolled (optionally cold rolled after annealing the hot-rolled steel sheet), the decarburization annealing, after which the magnesia on the surface It is formed upon high temperature finish annealing after coating.
　Further, phosphate coating layer, after the high-temperature finish annealing for forsterite layer formed, is formed by performing baking after performing the coating of the treatment liquid composed mainly of such flattening and phosphate that. A treatment liquid coating consisting mainly of such flattening and phosphate may be performed simultaneously, it may be performed separately.
[0003]
　Forsterite layer is located between the steel sheet and phosphate coating layer contributes to improvement of adhesion between the steel sheet and phosphate coating layer as an intermediate layer.
　Both primary coatings referred phosphate coating layer improves the iron loss by reducing the eddy current loss to impart insulating properties to the electromagnetic steel sheet, thereby improving the energy efficiency of electric equipment.
[0004]
　However, in producing the iron core of the transformer or by processing the electromagnetic steel sheet, the workability of the electrical steel sheet, heat resistance and sliding property is inferior, there is a case where the insulating film at the time of stress relief annealing is peeled. In this case, there is a risk that the insulation may decrease the efficiency of the electrical device decreases. Further, when these properties are inferior, in manufacturing an iron core, it takes time to laminating electromagnetic steel plates, workability and assembling efficiency is deteriorated.
　Therefore, in recent years, the phosphate coating layer, in addition to insulating properties also corrosion, heat resistance, slip properties, or various properties such as processability (film properties) is required.
[0005]
　The insulation coating of the oriented electrical steel sheet, other than the above to confer surface tension electrical steel sheet, it is known that a characteristic of improving the magnetic properties of the grain-oriented electrical steel sheet. Electromagnetic steel plates tension is iron loss is reduced by domain wall motion is facilitated. Transformer having an iron core made from oriented electrical steel sheets, by reducing the iron loss oriented electrical steel sheet, magnetic distortion can be reduced, which is one of the main causes of noise.
[0006]
　For example, Patent Document 1, on the forsterite film formed on the surface of the steel sheet after finish annealing, phosphates having a specific composition, chromate, an insulating film treatment solution mainly composed of colloidal silica was applied by baking Te, an insulating coating to impart high tension steel plate (high-tensile insulating film) is formed on the surface of the steel sheet, a method of reducing the iron loss and magnetostriction of grain-oriented electrical steel sheet is described.
　Further, Patent Document 2, which is formed by a specific amount deposited a treatment liquid phosphate and chromate and glass transition point as a main component and 950 ° C. ~ 1200 ° C. of colloidal silica, high tensile oriented electrical steel sheet having an insulation coating is described.
[0007]
　According to the above disclosed in Patent Document 1 and Patent Document 2 technology, large film has a tension (effect of imparting tension to the steel plate), and an insulating film having excellent various film properties can be obtained. However, chromate is compounded chromium compounds in any of the insulating coating. As environmental problems in recent years, is to limit the use of banned or chromate use chromate has been demanded.
[0008]
　As a technique for producing an insulating coating containing no chromate, Patent Document 3, colloidal silica SiO 2 and 20 parts by weight, and 10 to 120 parts by weight of aluminum phosphate, boric acid from 2 to 10 parts by weight If, coated Mg, Al, Fe, Co, Ni, a coating treatment solution containing a one or a total of 4 to 40 parts by weight selected from among each of sulfate Zn steel sheet, 300 a method of forming an insulating film by ℃ at temperatures above baking process is described.
　Further, Patent Document 4, Ca, Mn, Fe, Zn, Co, Ni, Cu, organic acid salts selected from B and Al, formate, acetate, oxalate, tartrate, lactate, citrate salt, techniques have been described for grain oriented electrical steel sheet for surface-treating agent not containing chromium characterized by containing one or more organic acid salts selected from succinate and salicylate.
[0009]
　However, in the method of Patent Document 3 has a problem that lowers the corrosion resistance of the insulating coating by sulfate ions in sulfates. Further, the surface treatment agent of Patent Document 4, there is a problem with discoloration and solution stability of the insulating coating by an organic acid in an organic acid salt, was required further improvement.
[0010]
　Patent Document 5, a phosphate and colloidal silica as a main component, a metal component in the phosphate, divalent metal elements, trivalent metal elements, and the tetravalent metal elements, respectively identified oriented electrical steel sheet characterized by containing an amount is described.
　However, in the technique described in Patent Document 5, the stability of the coated liquid by the metal component is a multi-type mixing is a problem of decrease.
[0011]
　Patent Document 6, a phosphate and colloidal silica as a main component, the crystallinity of the phosphate is limited to a specific range, oriented electrical steel sheet having a high tensile insulation coating containing no chromium are described ing.
　In the technique described in Patent Document 6, there is no problem of stability of the coating process liquid is lowered. However, in the technology described in Patent Document 6, there are restrictions on baking conditions. Therefore, it is difficult to form a stable coating, industrial productivity is disadvantageously lowered.
[0012]
　Patent Document 7, a nitrogen-containing compound is mixed into a mixture of phosphate and colloidal silica, chromeless tension coating treatment liquid which ratio was blended so that the above specified values of nitrogen and phosphorus in the coating is Have been described. In Patent Document 7, it is applied to the surface of the final finish-oriented electrical steel sheet after annealing, by baking at 350 ~ 1100 ° C., without the need to specially optimized underlying film, and sufficient excellent moisture absorption resistance it is described that it is possible to obtain a chromeless tension coating having both iron loss reducing effect.
　However, the technique described in Patent Document 7, mechanism contributing to the expression of the effect is not clear. In particular, baking the temperature range lower limit of is a 350 ° C. or higher, such a one desired effect at a low temperature baking temperature doubt, many unclear points to other.
CITATION
Patent Document
[0013]
Patent Document 1: Japanese Patent Publication 53-28375 Patent Publication
Patent Document 2: Japanese Patent Laid-Open 11-071683 discloses
Patent Document 3: Japanese Patent Publication 57-9631 discloses
Patent Document 4: Japanese Patent 2000-178760 JP
Patent Document 5: Japanese Patent 2010-13692 JP
Patent Document 6: Japanese Patent 2007-217758 JP
Patent Document 7: Japanese Patent 2012-158799 JP
Summary of the Invention
Problems that the Invention is to Solve
[0014]
　The present invention has been made in view of the above circumstances. The present invention does not contain chromium (especially chromium compounds), adhesion, corrosion resistance is good, and has an insulating coating which can impart a much higher tension than the conventional steel plate, the magnetic properties are good directional electromagnetic it is an object of the present invention to provide a steel plate.
Means for Solving the Problems
[0015]
　To achieve the above object, the present invention is summarized as following configuration.
(1) oriented electrical according to an embodiment of the present invention includes a steel sheet, and an insulating film formed on the surface of the steel sheet, the insulating coating contains phosphoric acid metal salt and colloidal silica and, relative to the phosphoric acid metal salt to 100 parts by mass, the a colloidal silica is 20-150 parts by weight, further, selected silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, from among the cordierite one or more microparticles, relative to the phosphoric acid metal salt to 100 parts by mass, 0.5 to 7 parts by weight containing an average particle size of the fine particles is 0.3 ~ 7.0 .mu.m, the phosphorus crystallinity of the acid metal salt is from 2 to 40% oriented electrical steel sheet characterized in that it does not contain chromium.
[0016]
(2) oriented electrical steel sheet according to the above (1), said phosphoric acid metal salt, Al, Ba, Co, Fe, Mg, Mn, 1 or 2 or more selected from Ni and Zn it may be a metal salt.
[0017]
(3) oriented electrical steel sheet according to (1) or (2) has an arithmetic average roughness Ra of the insulating coating is in the range of 0.1 ~ 0.4 .mu.m in the rolling direction, rolling direction and at right angles it may be in the range of 0.3 ~ 0.6 .mu.m in the direction.
[0018]
(4) above (1) oriented electrical steel sheet according to any one of - (3), the steel sheet contains, by mass%, C: 0.005% or less, Si: 2.5 ~ 7.0 % contained in the tissue of the steel sheet, the average crystal grain size of 1 ~ 10 mm, crystal orientation, (110) with respect to an ideal orientation of [001], 8 ° or less orientation deviation of the rolling direction with an average value it may have.
[0019]
(5) oriented electrical steel sheet according to any one of the above (1) to (4), between the insulating coating and the steel sheet may further have a forsterite film.
Effect of the invention
[0020]
　According to this aspect of the present invention, even though not containing chromium, adhesion and corrosion resistance is satisfactory, and has an insulating coating which can impart a much higher tension than the conventional steel plate, the magnetic properties are good It can provide grain-oriented electrical steel sheet.
DESCRIPTION OF THE INVENTION
[0021]
　As described above, in the grain oriented electrical steel sheet which has been granted in tension, the iron loss is reduced because the magnetic domain wall movement is facilitated. For insulating coating of oriented electrical steel sheet so as to impart tension to the steel sheet, it is effective to provide a difference in thermal expansion coefficient between the steel sheet and the insulating film. If the thermal expansion coefficient of the insulating coating is less than the steel plate, when the insulating film is baked, contraction of the steel sheet is larger than the shrinkage of the insulating coating. As a result, the steel sheet is subjected to tensile stress, while compressive stress is applied to the coating. Therefore, by reducing the thermal expansion coefficient of the insulating coating, the tensile stress (tension) applied to the steel sheet, it is possible to increase.
[0022]
　When the insulating coating is peeled off from the steel plate, to decrease tension applied to the steel sheet. Therefore, the insulating coating of oriented electrical steel sheet, excellent adhesion to the steel sheet is required. To enhance the adhesion, as forming an insulating film, a conventional, phosphoric acid metal salt, a mixture of colloidal silica and chromate are generally used.
[0023]
　Contain a chromate method for increasing the adhesion of the insulation coating is known. Meanwhile, conventionally, when mixing a relatively large amount of colloidal silica to metal phosphate, only a phosphoric acid metal salt and colloidal silica does not contain chromium difficult to obtain a high tensioning effect insulation coating It was.
　Therefore, the present inventors have found that an insulating film capable of imparting a high tension required in grain-oriented electrical steel sheet in the steel sheet, and made intensive studies to obtain an insulating film containing no chromium corresponding to environmental issues. As a result, the insulating coating mainly a metal phosphate and colloidal silica, the degree of crystallinity phosphoric acid metal salt are involved largely to the thermal expansion coefficient of the insulating coating, the crystallization of the metal phosphate by controlling the degree of 40% or less, it was found to be significantly increased coating tension while maintaining the adhesiveness. Furthermore, the present inventors have found that by the inclusion of certain particulate into the insulating coating has been found further that it is possible to improve the film tension.
[0024]
　Mechanisms film tension is significantly improved is not clear in detail by mixing the fine particles in the insulating film. However, the present inventors have made extensive studies on the reactivity of the phosphoric acid metal salts, by introducing a specific amount of highly stable particles in phosphoric acid metal salt of the specific compounding ratio and the colloidal silica, phosphoric acid film forming colloidal silica was found to be promoted metal salt moderately crystallized. Accordingly believed film tension when mixed particulate insulating film is greatly improved.
　The following describes oriented electrical steel sheet according to an embodiment of the present invention (grain-oriented electrical steel sheet according to the present embodiment).
[0025]
　Oriented electrical steel sheet according to the present embodiment includes a steel plate, and an insulating film formed on the surface of the steel sheet. The insulating coating contains phosphoric acid metal salt and colloidal silica as a main component. Per 100 parts by mass of phosphoric acid metal salts, colloidal silica contains from 20 to 150 parts by weight. Further, silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, with respect to one or more microparticles, 100 parts by weight of phosphoric acid metal salts selected from among cordierite, 0.5-7 mass part contains. The average particle diameter of the fine particles is the 0.3 ~ 7.0 .mu.m, the crystallinity of the metal phosphate is from 2 to 40%. The insulating film does not contain chromium.
　This insulating coating, phosphoric acid metal salts, (sometimes hereinafter referred treating agent) treating agent containing colloidal silica and fine particles is applied on the steel sheet surface, it is formed by further annealing.
　The insulating coating is a high tension insulating coating to impart high tension to the steel sheet.
[0026]

　insulating coating if it contains phosphoric acid metal salt, the effect can be obtained. Phosphoric acid metal salt is a Al, Ba, Co, Fe, Mg, Mn, Ni, is preferably one of a metal salt of Zn, Al, Mg, Mn, Ni, metal salts of either Zn it is more preferable. Insulating coating may comprise a metal salt thereof alone may contain a mixture of two or more. Case of containing phosphoric acid Ba, phosphate Ni, solubility, such as phosphoric acid Co is a low metal salt in an insulating coating, these metal salts are added to the treatment agent as an acidic solution, and colloidal solution or dispersion the liquid, is contained in the processing agent by any method, it may be annealed after applying the treatment agent on the surface of the steel sheet.
[0027]

　colloidal silica is not particularly limited.
　However, stability when the average particle diameter of colloidal silica was added to the treating agent as long as 5nm or more often, the colloidal silica can be uniformly dispersed in the insulating coating. On the other hand, if the average particle size is 50nm or less, good reactivity with phosphate upon annealing after applying the treatment agent, to enhance the chemical stability of the metal phosphate enough it can. As a result, moisture absorption resistance of the insulating coating is improved. Therefore, the average particle size of the colloidal silica is preferably from 5 nm ~ 50 nm, more preferably the average particle diameter is 6 nm ~ 15 nm.
　Further, as the type of colloidal silica, alkaline liquid property of the solution is neutral, but may also be used any of those acidic, especially colloidal surfaces is solution stability that has been subjected to Al treatment of the silica The preferred is excellent.
　Further, the shape of the colloidal silica is not particularly limited, from the viewpoint of film formability, shape silica is continuous with irregular or bead-shaped are preferred.
[0028]
　The proportion of the phosphoric acid metal salt and colloidal silica in the insulating film, relative to 100 parts by weight of phosphoric acid metal salts, colloidal silica is in the range of 20-150 parts by weight.
　If less than 20 parts by mass relative to the amount of 100 parts by mass phosphoric acid metal salt of colloidal silica, not sufficient tensioning effect. On the other hand, if 150 parts by mass, the crystallinity of the insulating film becomes excessively high, defects such as cracking and peeling the insulating coating tends to occur. Preferably, relative to 100 parts by weight of phosphoric acid metal salts, colloidal silica is 35-90 parts by weight. More preferably, relative to 100 parts by weight of phosphoric acid metal salts, colloidal silica is 40-55 parts by weight. The proportion of these components in the insulating film is equal to the proportion of the treatment agent for forming the insulating coating.
[0029]
　
　when the low crystallinity of the metal phosphate, surface high film tension smooth, highly corrosion resistant coating is obtained. However, if the crystallinity of the metal phosphate is less than 2% moisture by depending on the type of metal phosphate proceeds and condensation polymerization reaction even after the insulating film forming, as a result, to generate surplus phosphate or, in some cases corrosion resistance of the insulating coating is deteriorated. Therefore, the crystallinity of the metal phosphate is at least 2%. On the other hand, the degree of crystallinity is likely to film tension is degraded 40 percent. Therefore, the crystallinity of the metal phosphate is 40% or less. The crystallinity of the metal phosphate, and more preferably in the range of 5-20%.
[0030]
　The crystallinity of the metal phosphate, a grain-oriented electrical steel sheet insulating coating formed, by analyzing by X-ray structural analysis apparatus, it is possible to easily calculated. The calculation of crystallinity by X-ray diffraction, may be used a profile fitting method (profile fitting by peak separation). In this case, specifically, from the peak of the amorphous component and the crystalline component of the diffraction pattern obtained, we determined the respective scattering intensity by separating the background, the following equation (1) Crystallinity X ( %) is calculated. At that time, since colloidal silica also containing amorphous components, the content of colloidal silica to calculate the contribution of the amorphous halo correcting the amorphous scattering intensity A.
　= C X / (C + A) × 100
(1) C: crystalline scattering intensity, A: amorphous scattering intensity
[0031]

　The insulating coating, silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, include one or more particles selected from among cordierite. Particles added to be contained may be used any of the above alone, do not may be used as a mixture of two or more, used as an organic material is blended in a part with stabilizers and it may be.
　Conventionally, valence of divalent, trivalent, by mixing it into tetravalent and various metal phosphate processing agent, there is the processing agent becomes unstable. However, silicon carbide in the present embodiment, silicon nitride, aluminum nitride, boron nitride, sialon, the coating treatment solution by adding to one or more particulate treating agent of the particular particle size selected from among cordierite stability is good. Further, by containing the fine particles in the insulating film, it is possible to control the crystallinity of the metal phosphate, high insulation coating of film tension can be obtained. Further, by incorporating fine particles in the insulating film is also improved sliding properties of the insulating coating.
　Both of these fine particles, the thermal expansion coefficient is low and has a crystal structure in which there is a symmetry such as hexagonal or cubic. Silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, crystal system of one or more particles selected from among cordierite, when a hexagonal or cubic, more crystalline phosphoric acid metal salt It preferred because the ability to can be expected. Particulate hexagonal boron nitride, and more preferably it is aluminum nitride or cordierite.
[0032]
　The proportion of the fine particles in the insulating film, relative to 100 parts by weight of metal phosphate, in the range of 0.5 to 7 parts by mass. The proportion of the fine particles effects can not be sufficiently obtained to crystallize the metal phosphate is less than 0.5 part by mass. On the other hand, the existing ratio of 7 parts by mass of fine particles, there is a possibility that fine particles decreases the uniformity of the aggregate into the insulating film. Therefore, the existence ratio of the particles, relative to 100 parts by weight of phosphoric acid metal salt is 0.5 to 7 parts by mass. Preferably, 1 to 7 parts by mass, and more preferably 1 to 5 parts by weight.
　The proportion of the fine particles in the insulating coating can be obtained by the following method.
　That is, peeled from the steel sheet insulating coating of constant area, after measuring the weight of the peeled insulating coating, by dissolving the peeled insulating coating in an alkaline solution, separating the hard particles are dissolved in an alkaline solution. The weight of the separated particles was measured, obtaining the ratio of the weight of the pre-measured insulating coating by (gravimetric method) can be determined the existence ratio of the fine particles in the insulating film.
[0033]
　Diameter of the particles is in the range of 0.3 [mu] m ~ 7.0 .mu.m in average particle diameter in terms of volume. Liable aggregation in the treatment agent with an average particle size of less than 0.3μm microparticles, there is a possibility that fine particles are unevenly distributed in the insulating film. Further, the average particle size of 7.0μm greater than the thickness of the insulating coating is increased, the space factor of the steel sheet in the case of a grain oriented electrical steel sheet was an iron core may be reduced. Preferably, the average particle size is in the range of 0.3 [mu] m ~ 2.0 .mu.m.
　The average particle diameter of the fine particles can be determined by the micro track method. The micro-track method, which is also known as laser diffraction method or a laser diffraction scattering method, the time of measurement, after dissociation of pseudo-agglomeration pretreated with ultrasound for 5 minutes, transmittance of 80% -90% It is measured on set in. The refractive index, but it is to use it when there is a known number, if the refractive index is not known, by changing the refractive index was measured three times or more, other measurement principles and particle size distribution and the shape of the to adopt best matching refractive index.
[0034]
　Conventionally, in order to improve the sliding properties of the insulating coating, there is the addition of non-colloidal particles in an insulating film containing chromium. However, there is no report that the addition of particles to improve the film tension. Further, in the insulating film without the insulating film and the chromium containing chromium, quite different in nature. Therefore, the fine particles as described above, simply even if an attempt is contained in the insulating film not containing chromium, in the particle size and the presence ratio as shown in the present embodiment, it is not easy to be dispersed in the insulating coating .
　The insulation coating of the oriented electrical steel sheet according to the present embodiment, the adjustment of such baking conditions of the insulating coating, or by using a suitable surfactant according to the type of particles to be contained, predetermined particle size and existence ratio in contains fine particles.
　The insulation coating of the oriented electrical steel sheet according to the present embodiment, a chromium-free. This indicates that the content of chromium is below the detection limit (less than at most 10 ppm).
[0035]
　Coating weight of the insulation coating is 2 ~ 7 g / m 2 is preferred. Deposition amount 2 g / m 2 equal to or greater than, the sufficient tension is applied to the steel sheet, thereby improving the magnetic characteristics improving effect. The insulating property of the insulating coating, corrosion resistance, etc. are improved. Further, the amount of deposition of the insulating coating is 7 g / m 2 equal to or less than the decrease in space factor of the steel sheet in the case of using an iron core of the transformer can be prevented.
[0036]
　On the surface of the insulating film oriented electrical steel sheet according to the present embodiment will (insulation coating according to the present embodiment), there is unevenness is presumed to be due to the presence of fine particles. This unevenness, insulating coating has a predetermined surface roughness.
　By unevenness is present on the surface, to improve the sliding properties of the insulating coating in the manufacture of iron cores, also improved the steel sheet space factor of the iron core. The arithmetic mean roughness of the rolling direction (Ra) is not less 0.1μm or more, the arithmetic mean roughness of the rolling direction and the perpendicular direction (Ra) is equal to 0.3μm or more, to improve the sliding property at the time of the iron core manufacturing productivity can be improved. Also, arithmetic mean roughness of the rolling direction (Ra) is not more 0.4μm or less, if the arithmetic average roughness of the rolling direction and the perpendicular direction (Ra) is 0.6μm or less, the space factor of the steel sheet in the iron core There was increased, thereby improving the magnetic properties of the laminated iron core is. Therefore, the surface roughness of the insulating coating, an arithmetic average roughness (Ra), in the range of 0.1 ~ 0.4 .mu.m in the rolling direction, of 0.3 ~ 0.6 .mu.m in the direction perpendicular to the rolling direction it is preferably in the range.
　Cause of such irregularities on the surface of the insulating film is formed, for example burned coated by a roll coater or the like along the rolling direction, a portion of the fine particles present in the insulating coating, exposed on the surface of the insulating film it is presumed to be due to.
　Arithmetic average roughness, JISB0601: determined by according to (2013 edition), it is measured.
[0037]

　steel to deposit the insulating coating if oriented electrical steel sheet is not particularly limited. However, for example, grain-oriented electrical steel sheet produced using the technique disclosed in JP-A-7-268567, i.e., in mass%, 0.005% or less of C, 2.5 to Si ~ 7.0 % and containing an average crystal grain size of 1 ~ 10 mm, grain-oriented electrical steel sheet having the ideal orientation, the deviation of the orientation of the below 8 ° to the rolling direction with an average value of the crystal orientation (110) [001] it is preferably used, and the like.
[0038]
　The surface before the steel sheet to adhere the insulating film may be forsterite film is formed. In this case, the insulating coating is formed on the surface of the forsterite film. If forsterite film is formed between the steel sheet and the insulating coating, preferably improved adhesion between the steel sheet and the insulating film.
[0039]
　Next, a preferred manufacturing method of a grain-oriented electrical steel sheet according to the present embodiment.
　Oriented electrical steel sheet according to the present embodiment, regardless of the manufacturing process, as long as the above-described configuration, the effect is obtained. However, for example, the following, to apply the treatment agent to the surface of the steel sheet, dried, according to the manufacturing method further comprising the step of performing baking, so obtained stably preferred.
[0040]
　Method for producing a steel sheet for forming an insulating film on the surface is not particularly limited. Steel sheet manufactured by the method disclosed hitherto, preferably if oriented electrical steel sheet after finish annealing, and more preferably if oriented electrical steel sheet having a known forsterite film. Further, after finish annealing, washed with water removed excess annealing separator, subjected to pickling and water washing treatment with such as sulfuric acid bath, it is preferable to perform the activation of the surface cleaning and surface.
[0041]
　For example, the hot coil slab containing Si 2.0 ~ 4.0% by weight hot rolled, cold-rolled hot coil cold rolled or after annealing, of about 0.2 ~ 0.5 mm plate and a thickness of cold-rolled steel sheet, the cold-rolled steel sheet decarburization annealing, thereafter the state in which the annealing separator was applied mainly comprised of MgO, subjected to high temperature annealing in a batch furnace to 1200 ° C. before and after the so-called secondary recrystallization after forming the forsterite film on the surface causes the, the grain-oriented electrical steel sheet obtained by washing the excess MgO, may be used as a steel sheet for forming an insulating film on the surface.
[0042]
　To form the insulating coating on the steel sheet, coated with a treating agent on the surface of the steel sheet, dried, further subjected to baking. Treatment agent for forming the insulating film according to the present embodiment, phosphoric acid metal salts, colloidal silica and fine particles have been treating agent dispersed in a solvent such as water is preferred. The mixing ratio of each component, in terms of solid content, colloidal silica is preferably in the range of 20-150 parts by mass with respect to 100 parts by weight of phosphoric acid metal salts, fine particles is preferably in the range of 0.5 to 7 parts by weight. The further processing agent, boric acid, sodium boride, and titanium oxide, various oxides such as molybdenum oxide, pigments, may be added an inorganic compound such as barium titanate. That is, grain-oriented electrical steel sheet according to the present embodiment, although the basic in that it consists of a metal phosphate and colloidal silica and fine particles, with not jeopardized characteristics, various oxides as described above, inorganic the compound may contain. In particular, inorganic compounds such as pigments, increase the coating hardness not colored only, preferred because an effect of hardly attached flaw in the insulation film.
[0043]
　With the crystallinity of the metal phosphate into the desired range, in order to control the fine particles in a predetermined state, baking conditions of the insulating coating is important.　
　Heating rate during baking treatment is preferably in the range of 30 ° C. / sec ~ 100 ° C. / sec. The heating rate is within the above range can be easily controlled crystallinity in the range 2-40%. When the temperature rising rate is less than 30 ° C. / sec, there is a possibility that crystallization would proceed excessively undesirable. On the other hand, when the heating rate is at 100 ° C. / sec greater, there is a risk that crystallization becomes difficult to proceed in the reverse undesirable. Heating rate is more preferably in the range of 40 ° C. / sec ~ 70 ° C. / sec.
　Soaking temperature during baking process is preferably in the range of 800 ℃ ~ 1000 ℃. Tension and soaking temperature is lower than 800 ° C. is not applied sufficiently. On the other hand, the insulating coating soaking temperature exceeds 1000 ° C. cracking occurs, there is a possibility that the film tension is decreased and or insulating deterioration. Soaking temperature is more preferably in the range of 880 ℃ ~ 950 ℃.
　Soaking time is preferably in the range of 10 seconds to 60 seconds. Soaking time is insufficient seizure is less than 10 seconds there is a possibility that moisture absorption is degraded. On the other hand, in the soaking holding time is 60 seconds or more is likely to contain the flaw in the insulation coating. Soaking time is more preferably in the range of 15 seconds to 30 seconds.
　The steel sheet after baking (post-soaking), cooled in a non-oxidizing atmosphere from 20 ° C. / sec to 200 ° C. or less at an average cooling rate of 100 ° C. / sec. Preferred average cooling rate is 100 ° C. / sec from 50 ° C. / sec.
　By baking the insulating coating in this condition, the crystallinity of the metal phosphate in the range of from 2 to 40% and, it is possible to obtain an insulating film containing fine particles in a predetermined range.
[0044]
　May form an insulating film according to the present embodiment does not have a steel plate forsterite film. In this case, as in the case of having a forsterite film, washed with water removed excess annealing separator, pickling due sulfate bath, subjected to water washing treatment, after the activation of the surface cleaning and surface it may be formed an insulating film.
Example
[0045]
　It will now be described 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 not limited to this single example of conditions. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention may employ various conditions.
[0046]
　Si 3.2 mass%, the Al 0.027 wt%, 0.008 wt% of N, casting a molten steel containing C 0.08 mass%, to prepare a slab. The slab was heated performs hot-rolled to obtain a hot rolled steel sheet. For this hot rolled steel sheet was cooled from the annealing for 5 minutes at 1100 ° C.. To hot-rolled steel sheet after annealing to obtain a cold-rolled steel sheet thickness of 0.23mm perform cold rolling. Then to this cold-rolled steel sheet, subjected to 3 minutes decarburization annealing at 850 ° C., was coated with an annealing separator mainly comprised of MgO, was 20 hours final annealing at 1200 ° C.. The cut from the cold-rolled steel sheet after finish annealing the sample width 7 cm × length 32cm, while leaving forsterite film, remaining on the surface of the annealing separator was washed with water removed is, a steel sheet by performing a subsequent stress relief annealing Obtained.
[0047]
　The resulting steel sheet, by mass%, 0.001% and C, contains Si 3.2 mass%, in the tissue, the average crystal grain diameter of 1 ~ 10 mm, crystal orientation, (110) [ to the ideal orientation of 001, it had a deviation of 8 ° below the orientation in the rolling direction with an average value.
[0048]
　Next, using the fine particles shown in Table 1, after the metal phosphate solution was prepared at the mixing ratio shown in Table 2, the coating amount is 4.5 g / m 2 was coated with a roll coater to a steel sheet so as to be further baking under the conditions described in Table 2, by cooling in a non-oxidizing atmosphere to 200 ° C. or less, to obtain a grain oriented electrical steel sheets of examples 1 to 12 and Comparative examples 1-13. The obtained grain-oriented electrical steel sheet, were evaluated and the surface roughness and the film properties and magnetic properties. The results shown in Table 2, Table 3.
[0049]
　Boron nitride, aluminum nitride, silicon nitride, silicon carbide, alumina, sialon, for boehmite, with each of the particle size of commercially available products. For cordierite, magnesium carbonate, were blended so that the kaolinite, quartz powder cordierite composition, and calcined after mixing, then the pulverized to a predetermined particle size. For mullite, a powder of alumina and quartz were blended so that the mullite composition, calcined after mixing stirred, followed by a predetermined grinding process so that the particle size. The average particle diameter of the colloidal silica used was 15 nm.
[0050]
　Surface roughness, in conformity with JISB0601 (2013), in the direction perpendicular to the rolling direction and the rolling direction, were measured arithmetic mean roughness Ra.
[0051]
　Evaluation method of coating properties are as follows.
　Adhesion, was adhered to cellophane tape to the steel sheet samples of 30 mm × 200 mm, 10 mm [phi, 20 mm.phi, after bending wound around a round bar with a diameter of 30 mm?, Peeling conditions peeling the cellophane tape observed, and evaluated according to the following 0 to 30, was passed 10 or less.
　0: 10mmφ even without peeling
　10: peeling in 10Mmfai
　20: peeling in 20Mmfai
　30: peeling in 30mmφ
[0052]
　The corrosion resistance was evaluated with 5% salt spray test. The exposure time of 10 hours, was evaluated in 10 stage of the rust situation. The case of no rust and 10 were evaluated when the area rate of 50% of rust 1. In addition, it was passed 7 or more.
[0053]
　Coating tension was calculated backward from the curved state when peeling the one side of the insulating coating.

we claims

And the steel sheet,
　an insulating film formed on the surface of the steel sheet
has a,
　the insulating coating
　　contains phosphoric acid metal salt and colloidal silica, with respect to the 100 parts by weight of metal phosphate, the colloidal Jo silica is from 20 to 150 parts by mass,　
　　further, silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, one or more particles selected from among cordierite, the phosphoric acid metal salt relative to 100 parts by weight, 0.5 to 7 parts by weight containing,
　　average particle size of the fine particles is 0.3 ~ 7.0 .mu.m,
　　crystallinity of the metal phosphate is from 2 to 40%
　　containing no chromium
-oriented electrical steel sheet, characterized in that.
[Requested item 2]
　Direction of claim 1, wherein the metal phosphate is, Al, Ba, Co, Fe, Mg, Mn, characterized in that the one or more metal salts selected from the group consisting of Ni and Zn sex electromagnetic steel sheet.
[Requested item 3]
　The arithmetic average roughness Ra of the insulating coating is in the range of 0.1 ~ 0.4 .mu.m in the rolling direction, in the rolling direction and the perpendicular direction is in the range of 0.3 ~ 0.6 .mu.m
claims, characterized in that oriented electrical steel sheet according to 1 or claim 2.
[Requested item 4]
　The steel sheet contains, by
　mass%, C: 0.005% or
　less, Si: 2.5 ~ 7.0%
containing,
　in tissue of the steel sheet, the average crystal grain diameter of 1 ~ 10 mm, crystal orientation, (110) with respect to an ideal orientation of [001], with a deviation of the orientation of the below 8 ° to the rolling direction with an average value
oriented electrical according to any one of claims 1 to 3, characterized in that steel sheet.
[Requested item 5]
　In further has a forsterite film between said insulating film and said steel plate
oriented electrical steel sheet according to any one of claims 1 to 4, characterized in that.