The present invention relates to an excellent grain-oriented electrical steel sheet and a manufacturing method thereof in water resistance. In particular, the present invention relates to oriented electrical steel sheet no excellent forsterite film in water resistance.
　This application, on July 13, 2017, claiming priority on Japanese Patent Application No. 2017-137411 filed in Japan, the contents of which are incorporated herein.
BACKGROUND
[0002]
　Oriented electrical steel sheet is a soft magnetic material, mainly because it is used as core materials such as transformers, magnetic properties represented by high magnetic flux density and low core loss is required. Therefore, to ensure the required magnetic properties, the crystal orientation of the base material steel plate, for example, aligned in parallel to {110} plane in the steel sheet surface, and, with uniform <100> axis in the rolling direction orientation (Goss orientation ) is controlled to. To increase the integration of the Goss orientation, AlN, secondary recrystallization process using MnS or the like as an inhibitor is widely used.
[0003]
　To reduce iron loss, the surface of the base material steel plate is film is formed. This film, in addition to reducing the core loss as an electromagnetic steel veneer by applying tension to the base steel sheet, when used by laminating electromagnetic steel plates, to ensure electrical insulation between magnetic steel sheets, the core It is responsible for the function of reducing the iron loss of as.
[0004]
　As oriented electrical steel sheet film has been formed on the base steel sheet surface, for example, forsterite (Mg in the base steel sheet surface 2 SiO 4 finishing sintered pure coating a) The finished sintered pure film and the insulating film, respectively, are responsible for the function of tensioning to insulation and the base steel sheet.
[0005]
　Finishing sintered pure coating, in the finishing annealing causing the base steel sheet produce secondary recrystallization and annealing separator and the base steel sheet mainly composed of magnesia (MgO), for example, 600 ~ 1200 ° C. or more for 30 hours It is formed by reaction of during the heat treatment. Insulating coating, the base material steel sheet after finish annealing, for example, phosphoric acid or phosphate, colloidal silica, and co comprising chromic anhydride or chromium salt - coating solution was applied, 10 seconds at 300 ~ 950 ° C. It is formed by baking and drying the above.
[0006]
　To exert the required tension and insulating properties, coating so it must not be peeled off from the base material steel plate, these coating high adhesion to the base material steel plate is required.
[0007]
　Adhesion of the film is primarily, although due to the unevenness of the interface between the base steel sheet and finish sintered pure coating can be secured by the anchor effect, unevenness of the interface, also in disorders of the domain wall motion during electrical steel sheet is magnetized since, it has also become factors that impede the reduction of iron loss. Therefore, without the presence of finish sintered pure coating, while smoothing the interface, to ensure the adhesion of the insulating coating, in order to reduce iron loss, so far, the following techniques have been disclosed.
[0008]
　For example, Patent Document 1, the finishing sintered pure film is removed by a means pickling etc., techniques to smooth the surface of the steel sheet by chemical polishing or electrolytic polishing is disclosed. Patent Document 2, alumina (Al during finish annealing 2 O 3 with an annealing separating agent containing), However, in the technique of Patent Documents 1 and 2, the insulating film on the base steel sheet surface is a problem that it is difficult to contact.
[0009]
　In order to enhance the coating adhesion to the smoothed base material steel plate surface, it has been proposed to form an intermediate layer between the base steel sheet and the insulating film (the base film). For example, the number in the patent document 3, discloses a technique of forming an intermediate layer by applying an aqueous solution of phosphoric acid or alkali metal silicate, Patent Documents 4-6, which is appropriately controlling the temperature and atmosphere of the steel sheet technique of the external oxidation type oxide silicon film formed by heat treatment of tens of seconds to several minutes and the intermediate layer is disclosed.
[0010]
　Silicon oxide film of these external oxidation type, the improvement of the adhesion of the insulating coating, to reduce iron loss by smoothing the unevenness of the interface between the base steel sheet and its film, but exhibits a certain effect, in particular for the film adhesion, practically, I did not become sufficient, the silicon oxide film of an external oxidation type, further technical development has been promoted.
[0011]
　For example, Patent Document 7, in addition to an external oxide film mainly made of silicon oxide, a technique of forming a particulate external oxide is disclosed. Patent Document 8, a technique for controlling the form of an external oxide type oxide film mainly made of silicon oxide (cavity) is disclosed.
[0012]
　JP 9-10, metallic iron and metallic oxides outside oxide film of silicon oxide mainly (e.g., Si-Mn-Cr oxide, Si-Mn-CRal-Ti oxides, Fe oxides, etc.) technique of reforming is disclosed an external oxide film be contained. In Patent Document 11, with a coating layer mainly composed of silicon oxide formed by applying baking the oxide film mainly made of silicon oxide produced by the oxidation reaction, oriented electrical steel sheet is disclosed to be an intermediate layer of multi-layer It is.
[0013]
　Thus, the intermediate layer mainly composed of silicon oxide, while ensuring film adhesion regardless of the unevenness of the interface between the base steel sheet and its coating, the magnetic properties are good oriented electrical steel sheet is being put to practical use.
[0014]
　On the other hand, the insulating coating, in use of the electromagnetic steel sheet may be not a little by reaction alteration or degradation of the moisture in the oil moisture or core in the air is immersed in the insulating film, water resistance ensure there is a demand. Alteration or deterioration of the insulation film not only causes tension decrease due to changes in physical properties of the insulating film itself, due to peeling of the insulation coating, substantial tension reducing, also leads to a decrease in insulating properties. Therefore, ensuring the water resistance of the insulating coating, considering the until use environment of an electromagnetic steel sheet, an extremely important issue.
[0015]
　In general, to ensure the water resistance of the insulating film, often to contain Cr in an insulating film. However, it is expected that future commercialization, in the electromagnetic steel sheets using an external oxide film of silicon oxide mainly water issues insulating film has not been studied.
[0016]
　Furthermore, the coating of electrical steel sheets is a foreign material as a magnetic material, when used as a core, since the factor of lowering the space factor, the thickness of the coating is desired as small as possible, the thickness of the coating When thinner, water resistance of degradation of the coating is concerned that becomes remarkable.
CITATION
Patent Document
[0017]
Patent Document 1: Japanese Sho 49-096920 Patent Publication
Patent Document 2: Japanese Japanese Patent No. 4184809
Patent Document 3: Japanese Patent Laid-Open 05-279747 discloses
Patent Document 4: Japanese Patent Laid-Open No. 06-184762 Japanese
Patent Document 5: Japanese Unexamined Japanese Patent Application Laid-Open No. 09-078252
Patent Document 6: Japanese Patent Laid-Open 07-278833 discloses
Patent Document 7: Japanese Patent 2002-322566 JP
Patent Document 8: Japanese Patent 2002- 363763 JP
Patent Document 9: Japanese Patent 2003-313644 JP
Patent Document 10: Japanese Patent 2003-171773 JP
Patent Document 11: Japanese Patent 2004-342679 JP
Summary of the Invention
Problems that the Invention is to Solve
[0018]
　Currently, widely commercialized, coating structure of a typical grain oriented electrical steel sheet, as shown in FIG. 1, the basic three-layer structure of "base material steel plate 1 / forsterite film 2A / insulating film 3" structure It is set to. Insulating film 3, is generally a coating that phosphates (e.g., aluminum phosphate) to a colloidal silica and amorphous phosphate formed by baking by applying a solution mainly composed of a matrix.
[0019]
　On the other hand, by utilizing a thin intermediate layer, the film structure of the interface forms between the base steel sheet and the film macroscopically uniform and smooth and the oriented electrical steel sheet, as shown in FIG. 2, "the base material steel plate 1 / is a basic structure of three-layer structure of the intermediate layer 2B / insulating film 3 ".
[0020]
　However, silicon oxide (e.g., silicon dioxide (SiO 2 ), etc.) in the coating structure with an intermediate layer mainly composed of (Figure 2), compared with a coating structure having a finish sintered pure film (FIG. 1), the insulating film water resistance was found to be susceptible to degradation. The water resistance of the deterioration becomes remarkable when the film including the intermediate layer becomes thinner. Previously developed in oriented electrical steel sheet utilizing intermediate layer, water resistance of the deterioration of the insulating film is not considered.
[0021]
　To accommodate social demand energy saving, practical use of grain-oriented electrical steel sheet with reduced iron loss of the unevenness of the interface between the base steel sheet and the coating is smoothed is expected. In this realization, it is necessary to solve the practical use concerns generated when used in environment is water resistance problems. In particular, the thickness of the intermediate layer, even under conditions with minimal within a range of ensuring the film adhesion, it is important to propose a coating structure that can secure a sufficient water resistance.
[0022]
　Accordingly, the present invention forms an intermediate layer mainly composed of silicon oxide, to reduce iron loss by adjusting the interface between the base steel sheet and the coating on the smooth surface, further forming an insulating film containing Cr in the oriented electrical steel sheet, and an object thereof is to sufficiently secure the water resistance of the insulation coating, and to provide a grain-oriented electrical steel sheet to solve this problem.
Means for Solving the Problems
[0023]
　The present inventors have intensively studied a technique for solving the above problems.
[0024]
　First, First, the present inventors have found that the phenomenon that the water resistance of the insulation coating is deteriorated, the thickness of the intermediate layer mainly composed of silicon oxide is reduced given that becomes significant, the water resistance of degradation of the insulation coating , it was estimated to be a phenomenon associated with the mass transfer between the base steel sheet and the insulating film.
[0025]
　Although increasing the thickness of the intermediate layer mainly composed of silicon oxide is one solution, it is therefore thus lowers the space factor of the iron core, the present inventors have assuming the estimated, consider other methods, by noting modifying the intermediate layer itself. That is, if devising the formation process of the intermediate layer, even thinner thickness of the intermediate layer, but bypass the water resistance of degradation of the insulating film, and extensive studies.
[0026]
　Intermediate layer mainly composed of silicon oxide, and the base steel sheet surface forming the finish annealing film is intentionally suppressed finished sintered pure coating is substantially absent, the finish annealing film from the base material steel plate surface are substantially etc. all the removed base material steel plate surface, is formed by subjecting the thermal oxidation treatment (annealing in an atmosphere having a controlled dew point). After formation of the intermediate layer, baking the coating solution was applied to the surface of the intermediate layer to form an insulating film.
[0027]
　The present inventors have found that when forming the intermediate layer by thermal oxidation, in the base steel sheet surface, intentionally, by leaving the presence of some substance, attempted to modify the intermediate layer. As a result, the base steel sheet surface, if the intermediate layer is formed in a state one or both are present in the Al and Mg, to form an insulating film on the surface of the intermediate layer, it may improve water resistance of the insulation coating found.
[0028]
　Furthermore, the present inventors intentionally leaving a part of the oxide film and / or the annealing separating agent which has been conventionally removed, the base steel sheet surface, creating a state one or both are present in the Al and Mg I was thinking that. By changing the residual condition of oxide film and / or annealing separator to examine variation in the interface structure and the insulating film of the base material steel plate and its coating.
[0029]
　As a result, it led to obtain the following findings.
[0030]
　(A) when baking the insulating coating, the Fe from the base steel sheet in an insulating film contaminated with diffused.
[0031]
　(B) is low Fe concentration of the insulating film, although Cr in a non-crystalline phosphate which is a matrix of the insulating film is equivalent amount of solid solution, when the high Fe concentration of the insulating film, Fe and Cr in the insulating film crystalline phosphide is generated.
[0032]
　(C) When the crystalline phosphide is produced, Cr concentration of the matrix of insulating film is reduced, to deteriorate water resistance of the insulating coating.
[0033]
　(D) when baking the insulating coating, the phenomenon of Fe is diffused from the base material steel plate in the insulating film varies by one or both of the amounts of Al and Mg present in the base steel sheet surface during forming the intermediate layer, the by adjusting the amount to suppress the diffusion of Fe, suppressing a decrease in Cr concentration in the matrix of the insulating coating, it is possible to avoid the water resistance of degradation of the insulating film.
[0034]
　The gist of the present invention is as follows.
[0035]
　(1) grain-oriented electrical steel sheet according to an embodiment of the present invention, the base steel sheet and a base steel sheet on contact with arranged intermediate layer, the contact with arranged that in the outermost surface on the intermediate layer insulating film a grain-oriented electrical steel sheet having a preparative parallel, the average Cr concentration of the insulating film is 0.1 atomic% or more, cut surface cutting direction is parallel to the thickness direction (specifically, the thickness direction and when viewed in the rolling direction and a cutting plane perpendicular), the insulating film is, the region in contact with the intermediate layer has a compound layer containing crystalline phosphide, as a crystalline phosphide, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 or, (Fe, Cr) 2 P 2 O 7 contains at least one of the cutting of the when viewed in terms, the average thickness of the compound layer has a 0.5μm or less and der than 1/3 of the average thickness of the insulating film That.
[0036]
　The oriented electrical steel sheet according to (2) above (1), when viewed in the above cut surface, the insulating film is, in a region in contact with the compound layer has a Cr-depleted layer, the average Cr and Cr-depleted zone concentration, in atomic concentration is less than 80% of the Cr concentration in the insulating film, the average thickness of the Cr-depleted zone is at 0.5μm or less and even more than 1/3 of the average thickness of the insulating film good.
[0037]
　(3) In the oriented electrical steel sheet according to (1) or (2), when viewed in the above cut surface, the average thickness of the intermediate layer may be a 2 ~ 100 nm.
[0038]
　(4) The method of producing grain-oriented electrical steel sheet according to an embodiment of the present invention is a manufacturing method for manufacturing a grain-oriented electrical steel sheet according to any one of (1) to (3), a directional heating the slab for electrical steel sheet to 1280 ° C. or less, and the hot rolling step of performing hot rolling, the steel sheet after the hot rolling step, the hot-rolled sheet annealing step of performing hot-rolled sheet annealing, the hot rolled sheet annealing the steel sheet through the steps, the cold rolling step of performing once or twice or more cold rolling sandwiching the intermediate annealing, the steel sheet after the cold rolling step, the decarburization annealing step of performing decarburization annealing, decarburization the steel sheet after the annealing step, the annealing separator application step of applying the annealing separator, the steel sheet after the annealing separator application step, and finish annealing step of performing finish annealing, the steel sheet after the finish annealing step, surface smoothening processing performed, at least one of Al and Mg in the surface of the steel sheet 0.03 ~ 2.00 g m 2 and the steel sheet surface conditioning step of adjusting to be present, the steel sheet after the steel sheet surface conditioning step, a heat treatment, an intermediate layer forming step of forming an intermediate layer on the surface of the steel sheet, and, through the intermediate layer forming step steel sheet, and baked by applying an insulating film-forming solution containing a phosphate and colloidal silica and Cr, and an insulating film forming step of the insulating film formed on the surface of the steel sheet.
[0039]
　(5) In the manufacturing method of the grain-oriented electrical steel sheet according to (4), in the steel sheet surface conditioning step, leaving a portion of the film produced in the finish annealing step, the amount of oxygen 0.05 to the residual film 1.50 g / m 2 may be adjusted.
[0040]
　In (6) above (4) or the method of manufacturing the oriented electrical steel sheet according to (5), an intermediate layer forming step, the steel sheet after the steel sheet surface conditioning step, dew point: in an atmosphere of -20 ~ 0 ° C., subjected to heat treatment for holding at a temperature range of 600 ~ 1150 ℃ 10 ~ 60 seconds to form an intermediate layer, then with an insulating film forming step, the steel sheet through the intermediate layer forming step, phosphoric acid or phosphate, colloidal silica, and, co comprising chromic anhydride or chromium salt - applying a coating solution may be formed an insulation film subjected to baking to hold 300 ~ 900 ° C. in a temperature range 10 seconds or more.
The invention's effect
[0041]
　According to this aspect of the present invention, to form an intermediate layer mainly composed of silicon oxide, the interface between the base steel sheet and the coating was adjusted to a smooth surface to reduce iron loss, further containing Cr insulation in grain-oriented electrical steel sheet to form a film, it is possible to sufficiently secure the water resistance of the insulating coating, it is possible to provide an excellent grain-oriented electrical steel sheet in water resistance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042]
It is a cross-sectional view schematically showing the FIG. 1 coating structure of a conventional grain-oriented electrical steel sheet.
It is a cross-sectional view schematically showing the FIG. 2 another film structure of the conventional oriented electrical steel sheet.
3 is a schematic sectional view showing a film structure of the grain-oriented electrical steel sheet according to an embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0043]
　The following describes in detail preferred embodiments of the present invention. However, the present invention is not limited only to the configuration disclosed in this embodiment, and various modifications are possible without departing from the scope of the present invention. In addition, the numerical limitation range below the lower limit value and the upper limit value is included in the range. A number indicating the "super" or "less than", the value is not included in the numerical range.
[0044]
　Hereinafter, oriented electrical steel sheet according to the present embodiment and its manufacturing method will be described in detail.
[0045]
　A. Oriented electrical steel sheet
　oriented electrical steel sheet according to the present embodiment (hereinafter sometimes referred to as "the present invention electrical steel sheet".) Is finished sintered pure coating on the surface of the base material steel plate substantially absent, the mother is the intermediate layer is formed mainly of silicon oxide on the surface of the wood steel sheet insulating coating is formed this intermediate layer on the surface mainly of phosphate and colloidal silica and baked by applying a solution containing Cr a grain-oriented electrical steel
　sheet, (i) and the above average Cr concentration of the entire insulating film is 0.1 atomic% or
　more, (ii) within the insulating
　　film, (ii-1) (Fe, Cr ) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , and, (Fe, Cr) 2 P 2 O 7 1, two or more crystallinity phosphorus compound layer compound is present, is formed in a region in contact with the surface of the intermediate layer,
　　(II- ) Thickness of the compound layer, in the following 1/3 of the thickness of the insulating film, and may be at 0.5μm or less.
[0046]
　Specifically, the insulating film oriented electrical steel sheet according to the present embodiment, comprising a base steel sheet, and the base steel sheet intermediate layer disposed on and in contact with the, and contact with arranged that in the outermost surface on the intermediate layer a grain-oriented electrical steel sheet having bets,
　average Cr concentration of the insulating film is not more than 0.1 atomic% or more and 5.1 atomic%,
　the cut surface (in detail the cutting direction is parallel to the thickness direction when viewed in the thickness direction and parallel to and rolling direction and a cutting plane perpendicular), the insulating film is, the region in contact with the intermediate layer has a compound layer containing crystalline phosphide,
　crystalline phosphides as, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 of at least one of includes,
　when viewed in the above cut surface, the average thickness of the compound layer, be 50nm or more and 0.5μm or less And it may be at 1/3 or less of the average thickness of the insulating film.
[0047]
　Finish annealing film, due finish annealing, by reacting annealing separator and the base steel sheet is a film formed on the surface of the base material steel plate. Incidentally, the finish annealing film is the reaction product of the annealing separating agent and the base steel sheet (e.g., oxides containing inorganic mineral or Al, such as forsterite) as well, including the annealing separator of the unreacted it may be Idei.
[0048]
　The finished sintered pure coating substantially nonexistent base steel sheet surface, the base steel sheet surface forming the finish annealing film is intentionally suppressed finished sintered pure coating does not substantially exist, and, the base steel sheet surface finish annealing film from means substantially all removed base material steel plate surface. In addition, the base material steel plate surface finish sintered pure coating is substantially absent, in the manufacturing method described in the section "B. Directionality method for manufacturing electrical steel sheet", in the steel sheet surface conditioning step, after the finish annealing finishing sintered pure coating on the base steel sheet surface portion is remaining, then in the subsequent intermediate layer forming step process, including the base material steel plate surface substantially being entirely eliminate the finish annealing film.
[0049]
　The following describes the present invention electrical steel sheet.
[0050]
　The present invention electrical steel sheet is that diffusion of Fe conventional silicon oxide from the base material steel plate which has not been considered in the electrical steel sheet using an intermediate layer mainly into the insulating film, by reaction with the base steel sheet and the insulating film it is obtained by taking into account the deterioration of the insulating film. The method of adjusting one or both of the amount of Al and Mg present in the base steel sheet surface during formation of an intermediate layer, modifying the intermediate layer, to suppress the diffusion of Fe from the base steel sheet to insulating coating, suppressing a decrease in Cr concentration in the matrix of the insulating film, resulting in inhibited water resistance of degradation of the insulation coating.
[0051]
　3, a film structure of the present invention electrical steel sheet schematically showing. Coating structure of the present invention electrical steel sheet (hereinafter sometimes referred to as "the present invention film structure".), The intermediate layer 2B is disposed in contact with the base steel sheet 1, in contact with the intermediate layer 2B is disposed an insulating film 3 there. The insulating film 3 has a compound layer 3A and the Cr depleted layer 3B. The compound layer 3A is disposed at a position in contact with the intermediate layer 2B, Cr-depleted zone 3B is disposed at a position in contact with the compound layer 3A. Thus, the present invention coating structure is cut surface cutting direction is parallel to the thickness direction (specifically, the plate thickness direction and parallel to and rolling direction and a cutting plane perpendicular) when viewed in, as described above It is the basic structure of the five-layer structure.
[0052]
　Hereinafter, each layer will be described of the present invention electrical steel sheet.
[0053]
　1. Intermediate layer
　The intermediate layer is formed on the base steel sheet surface finish sintered pure coating does not substantially exist, it is a layer mainly composed of silicon oxide. The intermediate layer in the present invention coating structure, other to adhere the the insulating coating base steel sheet, has a function of suppressing diffusion of Fe from the base steel sheet to insulating coating.
[0054]
　Intermediate layer means a layer that exists between the base steel sheet, and an insulating film (including a Cr-depleted layer and the compound layer). The intermediate layer is, specifically, as described in "B. Fabrication method 8. intermediate layer forming step of a grain-oriented electrical steel sheet", for example, thermal oxidation of the finish annealing film and the base steel sheet (dew point layer and which is formed from the resulting product by annealing) in an atmosphere having a controlled coating material, the deposited material, plating materials, and / or a layer formed of a product produced by thermal oxidation of the base material steel plate and the like.
[0055]
　Silicon oxide forming a main body of the intermediate layer is preferably SiOx (x = 1.0 ~ 2.0) , SiOx (x = 1.5 ~ 2.0) is more preferable in terms of stability of the silicon oxide. If Hodokose heat treatment to form a silicon oxide base material steel plate surface sufficiently, silica (SiO 2 can be formed).
[0056]
　To form the intermediate layer, to the base steel sheet, the hydrogen 50 to 80 vol%, and the balance: consists of nitrogen and impurities, dew point: -20 ~ at 2 ℃ atmosphere, of 600 - 1150 ° C. the heat treatment of the general conditions of holding at a temperature range from 10 seconds to 600 seconds is subjected. In the intermediate layer formed by the heat treatment, silicon oxide remains amorphous. Therefore, the intermediate layer has a high strength to withstand thermal stresses and elasticity increases, the dense material of the thermal stress can be easily relaxed.
[0057]
　The intermediate layer is composed mainly of silicon oxide, therefore, the Si high concentrations (e.g., Si: 0.80 wt% or more 4.00 mass%) base steel sheet and a strong chemical affinity containing at is expressed Te be firmly adhered.
[0058]
　If the thickness of the intermediate layer is thin, the thermal stress relaxation effect is not sufficiently expressed, can not be sufficiently ensured film adhesion, it can not secure sufficient water resistance by suppressing the deterioration of the insulation film, the intermediate layer thickness It is is preferably more than 2nm in average, more preferably not less than 5 nm. On the other hand, if the thickness of the intermediate layer is thick, with the thickness becomes uneven, since the defects of voids and cracks in the layer occurs, the thickness of the intermediate layer is preferably 400nm or less on average, more is 300nm or less preferable.
[0059]
　The thickness of the intermediate layer, it is made thinner within a range capable of securing the film adhesion is, by shortening the forming time, can also contribute to a high productivity, also a reduction in the space factor when using as a core can be suppressed, the thickness of the intermediate layer is more preferably 100nm or less on average, and most preferably not 50nm.
[0060]
　The intermediate layer is considered to have a characteristic chemical composition or structure derived from Al and / or Mg present in the base steel sheet surface during forming the intermediate layer. However, currently, the distinct features are not apparent in the chemical composition or structure of the intermediate layer.
[0061]
　2. Insulating coating
　insulating coating, the surface of the intermediate layer is formed by baking by applying a solution containing Cr as a main component phosphate and colloidal silica. Average Cr concentration of the entire insulating film is 0.1 atomic% or more. The upper limit of the Cr density of the entire insulating film is not particularly limited, an average, preferably 5.1 atomic%, and more preferably on average 1.1 atomic%. Insulating coating, in addition to reducing the core loss as an electromagnetic steel veneer by applying tension to the base steel sheet, the time of use of laminated electromagnetic steel plates, the ability to ensure electrical insulation between the magnetic steel sheets a.
[0062]
　Matrix of the insulating coating, for example, is composed of amorphous phosphate, in which Cr is solid-solved. Amorphous phosphate constituting the matrix is, for example, aluminum phosphate, magnesium phosphate and the like.
[0063]
　In the present invention coating structure, as shown in FIG. 3, the insulating film 3 has a compound layer 3A and the Cr depleted layer 3B, the intermediate layer 2B on the contact with the compound layer 3A disposed, in contact with the compound layer 3A Cr-depleted layer 3B is disposed, in contact with the Cr-depleted layer 3B insulating film (the remainder excluding the compound layer 3A and the Cr depleted layer 3B) is disposed.
[0064]
　(1) compound layer
　on the compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , and, (Fe, Cr) 2 P 2 O 7 1, two or more crystallinity phosphide contains.
[0065]
　In the present invention electrical steel sheet, Cr atomic ratio in the metal element contained in the crystalline phosphide (Fe and Cr) is 0 percent. If crystalline phosphide contains no Cr, since the Cr concentration in the matrix of the insulating coating is not reduced, is not degraded water resistance of the insulating coating. Therefore, the issue of "Ensuring water-resistant" does not occur. Atomic ratio of the metal element contained in the crystalline phosphides varies in the thickness direction, the side close to the base steel sheet, the atomic ratio of Fe is high (atomic ratio of Cr is low). General, if the insulating film containing Cr, the side close to the base steel sheet, Cr atomic ratio in the metal element contained in the crystalline phosphides decreases the extent of 90% or less.
[0066]
　Compound layer, crystalline phosphide is formed by being formed in the insulating film. Specifically, the base material steel plate through the intermediate layer Fe is diffused into the insulating film, Fe concentration is increased in the region of the insulating film in contact with the intermediate layer, reacts with Fe and Cr in this area crystals forming a sexual phosphide, resulting in crystalline phosphides are formed area is the compound layer in the insulating film.
[0067]
　The thickness of the compound layer, one third of the thickness of the insulating film, or, if it exceeds 0.5 [mu] m, in some cases the water resistance of the insulation coating is deteriorated. In the present invention electrical steel sheet, when the intermediate layer is formed, the amount of one or both of Al and Mg that exist in the base steel sheet surface is adjusted to a proper amount, suppresses the diffusion of Fe from the base steel sheet to insulating coating. This suppresses the formation of a compound layer, the thickness of the compound layer below 1/3 of the thickness of the insulating film, and controls the 0.5μm or less, as a result, sufficient water resistance of the insulation coating it can be ensured.
[0068]
　The average thickness of the compound layer, the following 1/3 of the average thickness of the insulating film, and, preferably at 0.5μm or less, more preferably 0.3μm or less, more preferably 0.1μm or less. The lower limit of the thickness of the compound layer is not particularly limited, for example if 10 nm. The thickness of the lower limit of the compound layer, 50 nm are preferred, more preferably 100 nm.
[0069]
　(2) Cr-depleted zone
　Cr-depleted zone is the average value of the Cr concentration in the entire insulating film, a region where the Cr concentration of less than 80%. That is, the average Cr concentration of the Cr-depleted zone is in atomic concentration, less than 80% of the average Cr concentration in the insulating film. The lower limit of the average Cr concentration of the Cr-depleted zone is not particularly limited as long as it is a, for example, 0 percent. The average thickness of the Cr-depleted zone is 1/3 with a thickness of the insulating film, and is preferably 0.5μm or less. This makes it possible to more sufficiently ensure the water resistance of the insulating coating.
[0070]
　Cr-deficient layer, Cr concentration is formed by reduction in the area in contact with the compound layer. Specifically, Cr concentration of the compound layer by crystallinity phosphide is formed is reduced, Cr is diffused from the insulating film in contact with the compound layer to the compound layer, Cr in the region of the insulating film in contact with the compound layer concentration is lowered, as a result, the region where the Cr concentration was reduced in the insulating film is Cr-depleted zone.
[0071]
　The thickness of the Cr-depleted zone, one third of the thickness of the insulating film, or, if it exceeds 0.5 [mu] m, in some cases the water resistance of the insulation coating is deteriorated. In the present invention electrical steel sheet, when the intermediate layer is formed, the amount of one or both of Al and Mg that exist in the base steel sheet surface is adjusted to a proper amount, suppresses the diffusion of Fe from the base steel sheet to insulating coating. Thus, to suppress the formation of Cr-depleted layer, the average thickness of the Cr-depleted zone, 1/3 or less of the thickness of the insulating film, and controls the 0.5μm or less, as a result, water resistance of the insulation coating sex can be sufficiently secured.
[0072]
　The average thickness of the Cr-depleted zone is 1/3 with a thickness of the insulating film, and, preferably at 0.5μm or less, more preferably 0.3μm or less, more preferably 0.1μm or less. In addition, Cr-deficient layer may not exist at all. That is, the average thickness of the Cr-depleted zone can be equal to or greater than 0 .mu.m, however, the average thickness of the Cr-depleted zone is more preferably 50nm. When the average thickness of the Cr-depleted layer is 50nm or more, the Cr-depleted layer acts as a stress relaxation layer, the film can be easily relaxing thermal stress overall insulating coating. The lower limit of the thickness of the Cr-depleted zone is more preferably 100 nm.
[0073]
　(3) variation in composition layer
　is referred to as the aforementioned compound layer and the Cr depleted layer region of the combined composition variation layer.
[0074]
　(4) insulating film across
　present invention electrical steel sheet, since it is intended to have a concentration of Cr in the insulating film to solve the problem of deterioration water resistance of the insulating film decreases, essential that the insulating film contains Cr it is. In recent years, it has been promoted the development of the insulating film which does not contain Cr, Such electrical steel sheet insulating coating is formed, there is no technical problem of the present invention electrical steel sheet. The present invention electrical steel sheet, the average of the Cr density of the entire insulating film is characterized in that 0.1 at% or more.
[0075]
　Insulating coating of the present invention electrical steel sheet is disposed in contact with the surface of the intermediate layer, the presence status of crystallinity phosphide according to the thickness direction is controlled, preferably also controlled Cr concentration according to the thickness direction there. Therefore, the present invention electrical steel sheet, the water resistance of the insulating film can be sufficiently secured, can be used without problems for a long time at practical.
[0076]
　Insulating coating, mainly composed of phosphate and colloidal silica, containing Cr. This insulating coating, the average Cr concentration as a whole film is not particularly limited as long as it is 0.1 atom% or more. For example, it may contain a chromate. Further, the insulation coating, unless the effects of the present invention electrical steel sheet is lost, in order to improve various properties, may contain a variety of elements or compounds.
[0077]
　If the thickness of the insulating film becomes thinner, with tension applied to the base material steel plate becomes small, the insulation resistance even not only reduced, ensuring water resistance becomes difficult. Therefore, the thickness of the entire insulating film is preferably not less than 0.1μm in average, more preferably not less than 0.5 [mu] m. On the other hand, if the thickness of the entire insulating film exceeds 10 [mu] m, the formation step of the insulating film, there is a possibility that cracks occur in the insulating film. Therefore, the thickness of the entire insulating film is preferably 10μm or less in average, more preferably not more than 5 [mu] m.
[0078]
　Incidentally, if necessary, laser, plasma, mechanical methods, etching, and other methods may be subjected to magnetic domain refining treatment for forming a localized microscopic strain region, or localized groove.
[0079]
　3. Base material steel plate
　present invention electrical steel sheet, characterized in that it is a five-layer structure as described above. In the present invention electrical steel sheet, the chemical composition and structure, etc. of the base material steel plate is not relevant to the present invention coating structure directly. Therefore, in the present invention electrical steel sheet can be used the base steel sheet is not particularly limited, a typical base material steel plate. The following describes the base material steel plate of the present invention electrical steel sheet.
[0080]
　(1) Chemical Composition
　The chemical composition of the base steel sheet may be any chemical composition of the base steel sheet in a typical grain oriented electrical steel sheet. However, oriented electrical steel sheet, because it is produced through various processes, for composition of the preferred material billet (slab) and the base steel sheet in order to produce the present invention electrical steel will be described below. % Of the chemical composition means mass%.
[0081]
　Chemical composition of the base steel sheet
　base material steel plate of the present invention electrical steel sheet, for example, Si: contains 0.8 ~ 7.0%, C: 0.005 % or less, and, N: limited to 0.005% or less and, the balance being Fe and impurities.
[0082]
　Si: 0.8 or more and 7.0% or less
　silicon (Si) reduces the iron loss by increasing the electrical resistance of the grain-oriented electrical steel sheet. If Si content is less than 0.5%, this effect can not be obtained sufficiently. A preferable lower limit of Si content is 0.5%, more preferably 0.8%, more preferably 1.5%, more preferably from 2.5%. On the other hand, when the Si content exceeds 7.0%, the saturation magnetic flux density of the base material steel plate is reduced. Therefore, the iron loss is deteriorated. The preferable upper limit of the Si content is 7.0%, more preferably 5.5%, more preferably from 4.5%. In the present invention electrical steel sheet, Si content of the base material steel plate is preferably 0.8 or more and 7.0% or less.
[0083]
　C: 0.005% or less
　carbon (C) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. C content is preferably limited to 0.005% or less. The preferable upper limit of the C content is 0.004%, more preferably 0.003%.
[0084]
　N: 0.005% or less
　Nitrogen (N) forms a compound in the base steel sheet in order to degrade the iron loss, the less preferred. N content is preferably limited to 0.005% or less. The preferable upper limit of the N content is 0.004%, more preferably 0.003%.
[0085]
　The remainder of the chemical composition of the base material steel plate described above is Fe and impurities. Herein, the term "impurities", when manufacturing the base material steel plate industrially, components contained in the raw materials or inevitably mixed from the components to be mixed in the manufacturing process, substantial effects for the present invention It means an element that does not affect the.
[0086]
　Also, the base material steel plate of the present invention electrical steel sheet, in a range that does not disturb a property as a selective element in place of part of Fe is the balance, for example, acid-soluble Al (acid-soluble aluminum), Mn (manganese), S (sulfur), Se (selenium), Bi (bismuth), B (boron), Ti (titanium), Nb (niobium), V (vanadium), Sn (tin), Sb (antimony), Cr (chromium), Cu (copper), P (phosphorus), Ni (nickel), may contain at least one selected from Mo (molybdenum).
[0087]
　The content of the selected element as described above may be, for example, less. The lower limit of the selection element is not particularly limited, the lower limit may be 0%. These selection elements be contained as an impurity, the effect of the present invention electrical steel sheet is not impaired.
　　Acid-soluble Al: 0% or more and 0.065 or
　　less, Mn: 0% or more and 1.00% or less,
　　S and Se: 0% in total and 0.015 or
　　less, Bi: 0% or more and 0.010%
　　hereinafter, B: 0% or more and 0.080% or
　　less, Ti: 0% or more and 0.015% or
　　less, Nb: 0% or more and 0.20% or
　　less, V: 0% or more and 0.15% or less,
　　sn: 0% or more and 0.10% or less,
　　Sb: 0% or more and 0.10% or
　　less, Cr: 0% or more and 0.30% or
　　less, Cu: 0% or more and 0.40% or
　　less, P: 0% or more and 0.50% or
　　less, Ni: 0% or more and 1.00% or less, and
　　Mo: 0% or more and 0.10% or less.
[0088]
　Steel material piece component composition of (slab)
[0089]
　a. Si: 0.8% to 7.0% or less
　Si (silicon) is an element that reduces core loss by increasing electrical resistance. When Si exceeds 7.0%, cold rolling becomes difficult, since cracking during cold rolling is likely to occur, Si is not more than 7.0%. Preferably 4.5% or less, more preferably less than or equal to 4.0%. On the other hand, if the Si is less than 0.8%, the austenite γ transformation occurs during finish annealing, the crystal orientation of the grain-oriented electrical steel sheet is impaired, Si is 0.8% or more. Preferably 2.0% or more, more preferably 2.5% or more.
[0090]
　b. C: 0.085% or less
　C (carbon) is an element effective for formation of the primary recrystallization structure, but also adversely affects the elements in the magnetic properties. Therefore, before the finish annealing is subjected to a decarburization annealing the steel sheet, reduce C. When C exceeds 0.085% decarburization annealing time becomes longer, since the productivity in industrial production is impaired, C is not more than 0.085%. Preferably 0.080% or less, more preferably not more than 0.075%.
[0091]
　The lower limit of C is not particularly limited, in terms of formation of a primary recrystallization structure, C is preferably 0.020% or more, more preferably at least 0.050%.
[0092]
　c. Acid-soluble Al: 0.010% or more 0.065% or less
　acid-soluble Al (acid soluble Aluminum) is combined with N, is an element which forms a function as an inhibitor (Al, Si) N. If the acid soluble Al is more than 0.065%, the secondary recrystallization becomes unstable, acid-soluble Al is a 0.065% or less. Preferably 0.050% or less, more preferably 0.040% or less.
[0093]
　On the other hand, when the acid-soluble Al is less than 0.010%, Similarly, the secondary recrystallization becomes unstable, acid-soluble Al is 0.010% or more. In the finish annealing, by concentrating the Al on the surface of the steel sheet, in that it used as Al present on the surface of the steel sheet during forming the intermediate layer, acid-soluble Al is preferably 0.020% or more, more or more 0.025% preferable.
[0094]
　d. N: 0.004% to 0.012% or
　less, N (nitrogen) is combined with Al, an element which forms acts as an inhibitor (Al, Si) N. If N exceeds 0.012%, the likely entails defects called blisters in the steel sheet, N is not more than 0.012%. Preferably 0.010% or less, more preferably not more than 0.009%. On the other hand, when N is less than 0.004% or, because it is impossible to obtain a sufficient amount of inhibitor, N is 0.004% or more. Preferably 0.006% or more, more preferably 0.007% or more.
[0095]
　e. Mn: 0.05% to 1.00% or less,
　　　S and / or Se: 0.003% or more than 0.020%
　Mn (manganese), S (sulfur), and, Se (selenium) may function as an inhibitor is an element to form a MnS and MnSe to.
[0096]
　When Mn exceeds 1.00%, since the secondary recrystallization becomes unstable, Mn is not more than 1.00%. Preferably 0.50% or less, more preferably 0.20% or less. On the other hand, when the Mn is less than 0.05%, Similarly, the secondary recrystallization becomes unstable, Mn is less than 0.05%. Preferably 0.08% or more, more preferably 0.09% or more.
[0097]
　When S and / or Se exceeds 0.020%, the secondary recrystallization becomes unstable, S and / or Se is set to 0.020% or less. Preferably 0.015% or less, more preferably 0.012% or less, more preferably 0.010% or less. On the other hand, when the S and / or Se is less than 0.003%, Similarly, the secondary recrystallization becomes unstable, S and / or Se is set to 0.003% or more. Preferably 0.005% or more, more preferably 0.008% or more.
[0098]
　Note that "S and / or Se is 0.003 to 0.015%" are material steel piece, containing one of S and Se, which is one of S or Se is 0.003 to 0.015% the case, material steel piece, containing both of S and Se, means a case where the total amount of S and Se is 0.003% to 0.015%.
[0099]
　f. Balance
　balance consists of Fe and impurities. Note that the "impurities", in manufacturing the steel industrially, refers to those mixed ores as raw material, scrap or from the manufacturing environment and the like. That is, in the present invention electrical steel sheet, if within a range that does not inhibit the properties of interest, allowing the impurity is contained.
[0100]
　Strengthening and inhibitors function by compounds formed, in consideration of the influence on the magnetic properties, instead of a part of Fe in balance, may contain various elements. Type and amount of element to be contained instead of a part of Fe is, for example, Bi (bismuth): 0.010% or less, B (boron): 0.080% or less, Ti (titanium): 0.015% or less , Nb (niobium): 0.20% or less, V (vanadium): 0.15% or less, Sn (tin): 0.10% or less, Sb (antimony): 0.10% or less, Cr (chromium): 0.30% or less, Cu (copper) 0.40% or less, P (phosphorus): 0.50% or less, Ni (nickel): 1.00% or less, Mo (molybdenum): 0.10% or less, such as it is. The lower limit of the selection element is not particularly limited, the lower limit may be 0%.
[0101]
　(2) surface roughness of
　the present invention electrical steel (oriented electrical steel sheet having an insulation coating and the intermediate layer), when viewed in cutting plane becomes a thickness direction and parallel to and rolling direction and perpendicular, coating and the base steel sheet it is preferred that the interface to the irregularities are not formed with. That is, the roughness of the base material steel plate surface (the interface with the base steel sheet and the film), from the viewpoint of reducing the iron loss, for example, preferably 1.0μm or less in Ra (arithmetic average roughness). More preferably 0.8μm or less, more preferably 0.6μm or less. From the viewpoint of by applying a large tension to the steel sheet further reduced iron loss, the roughness is more preferably 0.5μm or less in the above Ra, or less and most preferably 0.3 [mu] m.
[0102]
　(3) the thickness of the base material steel plate
　thickness of the base material steel plate is not particularly limited, in order to further reduce the iron loss, the thickness is preferably 0.35mm or less in average, more preferably not more than 0.30 mm. Incidentally, the thickness of the base material steel plate is not particularly limited, the lower limit of the manufacturing limitations may be a 0.12 mm.
[0103]
　B. Method for producing a grain-oriented electrical steel sheet
　A method of manufacturing grain-oriented electrical steel sheet according to the present embodiment (hereinafter sometimes referred to as "production method of the present invention".) Will be described.
[0104]
　The present invention production process is a manufacturing method for manufacturing a grain-oriented electrical steel sheet described in the section "A. Oriented electrical steel sheet",
　by heating the slab for grain oriented electrical steel sheet to 1280 ° C. or less, the hot rolling hot rolling step of performing,
　in the steel sheet after the hot rolling step, hot-rolled sheet annealing step of performing hot-rolled sheet annealing,
　the steel sheet after the hot rolled sheet annealing step, more than twice interposing once or intermediate annealing cold rolling step of performing cold rolling,
　the steel sheet after the cold rolling step, decarburization annealing step of performing decarburization annealing,
　the steel sheet after the decarburization annealing step, the annealing separating agent for applying the annealing separator coating step,
　the steel sheet after the annealing separator application step, the finish annealing step of performing finish annealing,
　the steel sheet after the finish annealing step, subjected to a surface smoothing treatment, one or both of Al and Mg in the surface of the steel sheet 0.03 ~ 2.00 g / m 2 present as adjusted to steel Plate surface conditioning step,
　the steel sheet after the steel sheet surface conditioning step, subjected to a heat treatment, the intermediate layer forming step of forming an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet, and,
　the steel sheet through the above intermediate layer forming step on the surface, and baked by applying an insulating film-forming solution containing Cr as a main component phosphate and colloidal silica, an insulating film formation step, of forming an insulating film on the surface of the steel sheet.
[0105]
　The present invention electrical steel sheet, the intermediate layer was employed in order to avoid deterioration of the iron loss characteristics due to the unevenness of the interface between the finish annealing film and the base steel sheet, the adhesion between the coating and the base steel sheet by the intermediate layer ensuring, Sonouede, improving the water resistance of the insulating coating. Therefore, the present invention production process, the smooth surface and the base steel sheet surface, one or both of Al and Mg is 0.03 ~ 2.00 g / m 2 by controlling the conditions present, heat treatment is performed on the steel plate to form an intermediate layer, further, an insulating film containing Cr on the surface of the intermediate layer. Therefore, the present invention production process, in particular, annealing separator application step, the finish annealing step, the steel sheet surface conditioning step, an intermediate layer forming step, and controls the insulating film forming step.
[0106]
　The following describes each step of the manufacturing method of the present invention. The present invention production process, without being limited only to the production conditions described below, and various modifications are possible without departing from the scope of the present invention.
[0107]
　1. Hot rolling step
　directional slab for electrical steel sheet was heated to 1280 ° C. or less, subjected to hot rolling. The chemical composition of this slab, in particular, not limited to a particular chemical composition. For example, "A. Oriented electrical steel sheet 3. base steel sheet (1) chemical composition" chemical composition according to the section is preferred.
[0108]
　Slab, for example, the steel of the chemical composition was melted in a converter furnace or electric furnace or the like, if necessary, subjected to a vacuum degassing treatment, then rolled and continuous casting, or, slabbing after ingot it is possible to get. The thickness of the slab is not particularly limited, but is preferably 0.99 ~ 350 mm, more preferably 220 ~ 280 mm. Thickness may be 10 ~ 70mm about the slab (the so-called "thin-slab"). With thin slab, in the hot rolling process, it is possible to omit rough rolling before finish rolling.
[0109]
　The heating temperature of the slab, and 1280 ° C. or less. By the heating temperature of the slab and 1280 ° C. or less, problems (for example, high temperature heating furnace only needs molten scale amount surge, etc.) in high-temperature heating can be avoided. The lower limit of the heating temperature of the slab is not particularly limited, the heating temperature is too low, the hot rolling becomes difficult, so productivity is lowered, the heating temperature, considering the productivity in the range of 1280 ° C. or less it may be set Te. Further, after casting, it is omitted slab heating, until the temperature of the slab falls, it is also possible to start hot rolling.
[0110]
　The hot rolling step is subjected to rough rolling to the slab, further subjected to finish rolling, the hot rolled steel sheet having a predetermined thickness. After finish rolling completion, the hot rolled steel sheet is wound at a predetermined temperature. Thickness of hot-rolled steel sheet is not particularly limited, for example, the following are preferred 3.5 mm.
[0111]
　2. Hot-rolled sheet annealing step
　in the hot rolled sheet annealing step, applying a hot-rolled sheet annealing in a steel sheet which has undergone a hot rolling step. Hot-rolled sheet annealing condition may be a general conditions, for example, be held in a temperature range of 750 - 1200 ° C. 30 seconds to 10 minutes.
[0112]
　3. Cold rolling step
　in the cold rolling process, the steel sheet after the hot-rolled sheet annealing step, applying twice or more cold rolling sandwiching once or intermediate annealing. The cold rolling rate in the final cold rolling (final cold rolling reduction) is not particularly limited, from the viewpoint of controlling the crystal orientation in a desired direction, preferably at least 80%, more preferably at least 90%. Thickness of the cold-rolled steel sheet is not particularly limited, in order to reduce more the core loss is preferably 0.35mm or less, more preferably 0.30 mm.
[0113]
　4. Decarburization annealing step
　in the decarburization annealing step, the steel sheet after the cold rolling step is subjected to decarburization annealing. Specifically, by performing decarburization annealing the steel sheet which has undergone cold rolling step, the resulting primary recrystallization steel sheet, to remove the C in the steel sheet. Decarburization annealing, in order to remove C, it is preferable to perform in a moist atmosphere.
[0114]
　5. Annealing separator application step
　in the annealing separator application step, applying the annealing separator to a steel sheet which has undergone decarburization annealing step. Annealing separator, for example, alumina (Al 2 O 3 annealing separator composed mainly of), Annealing separating agent, annealing separator containing Al and / or Mg are preferred. If annealing separator contains Al and / or Mg, Al and / or Mg in the steel sheet surface needed when forming the intermediate layer, it can be supplied from the finishing sintered pure film.
[0115]
　It is also possible to use an annealing separator containing no Al and / or Mg. In this case, during the finish annealing, the Al of the annealing separator and the base steel sheet during reacts, finishing sintered pure film containing an oxide containing not a little Al on the steel sheet surface. Therefore, the Al surface of the steel sheet required when forming the intermediate layer, it can be supplied from the finishing sintered pure film.
[0116]
　Annealing separating agent, annealing separator consisting mainly of alumina is preferred. In this case, it is possible to suppress the unevenness is formed at the interface between the finish annealing film and the base steel sheet. Annealing separator consisting mainly of alumina, it is preferred to include both an alumina and magnesia. In this case, capture during annealing film finishing Al of the base material steel plate in, it is possible to purify the steel, Al of the base material steel plate in the internally oxidized, possible to suppress the iron loss is increased.
[0117]
　Annealing separator containing both alumina and magnesia is preferably a weight ratio of magnesia in the main component is less than 20% and 60%. The weight ratio of magnesia, 20% or more and 50% or less, particularly, more preferably 20% or more and 40% or less of the annealing separator.
[0118]
　When the mass ratio of the magnesia in the main component is less than 20% (mass ratio of alumina 80%), incorporated into annealing film finishing Al of the base material steel plate in, it may become difficult to purify the steel because the weight ratio of the magnesia in the main component is 20% or more (weight ratio of alumina less than 80%) are preferred. On the other hand, if the mass ratio of magnesia than 60% (mass ratio of the alumina is less than 40%) is, by reacting magnesia and the base steel sheet during finish annealing, the interface deterioration in uneven finish annealing film and the base steel sheet since risk of there, the mass ratio of the magnesia 60% or less (weight ratio of alumina 40 percent) are preferable.
[0119]
　Steel sheet coated with the annealing separator (decarburization annealed steel sheet), in a state in which wound in a coil shape, is subjected to a finish annealing step, the finish annealing is performed.
[0120]
　6. Finish annealing step
　in finish annealing step, annealed finish the steel sheet that has passed through the annealing separator application step, causing secondary recrystallization. During the finish annealing, annealing separator and the base steel sheet reacts, finishing sintered pure film on the steel sheet surface. Finishing sintered pure coating, including reaction products annealing separator, and the base steel sheet was produced by the reaction, it may include an annealing separator agent unreacted.
[0121]
　For example, when applied with an annealing separator consisting mainly of alumina, react annealing separator and the base material steel plate, the steel sheet surface, finish sintered pure film mainly made of oxide containing Al is formed that. If the application of the annealing separator containing no Al, reacts with Al of the annealing separator and the base steel sheet is replaced by a surface of the steel sheet, the finish sintered pure film mainly made of oxide containing not a little Al formation It is.
[0122]
　If the application of the annealing separator composed mainly of magnesia, reacted annealing separator and the base material steel plate, the steel sheet surface, forsterite (Mg 2 SiO 4 finishing sintered pure coating a) If the application of the annealing separator containing Al or Mg, annealing separator is not completely reacted and the base material steel plate sometimes finished sintered pure film containing an annealing separator, unreacted is formed.
[0123]
　In the finishing sintered pure process, it is preferable to apply the ShoJun finish so as not to interface irregularities forming the finish annealing film and the base steel sheet, and annealing separator containing Al and Mg, and / or, Al it is preferred to finish sintered pure coating comprising a reaction product containing or Mg is subjected to ShoJun finish as formed. In this case, the steel sheet surface conditioning step, by intentionally allowed to remain part of the finished sintered pure film on the surface of the steel sheet after finish annealing, one or both of 0.03 to Al and Mg on the surface of the steel plate 2 .00G / m 2 can be adjusted so that there.
[0124]
　Finish annealing conditions may be a general condition, for example, it may be heated in a temperature range of 1100 ~ 1300 ℃ 20 ~ 24 hours.
[0125]
　If the application of the annealing separator containing Al and / or Mg, finish annealing conditions, even common finish annealing conditions, annealing separator containing Al and Mg, and / or, Al or Mg finishing sintered pure coating comprising a reaction product containing is formed.
[0126]
　If applying the annealing separator containing no Al, by reacting the Al of annealing separator and the base steel sheet during the forming the finished sintered pure film mainly made of oxide containing not a little Al on the surface of the steel sheet , finish annealing conditions do not need to be a special annealing conditions, it may be a typical annealing conditions. When adjusting the amount of oxides contained in the final sintered pure film to a suitable amount is in the end of the finish annealing, the hydrogen: 100 vol% of N after the purification annealing in an atmosphere 2 switching to gas, 500 ° C. or higher, leaving the furnace temperature it preferably performed at 400 ° C. or higher.
[0127]
　Thus finish annealing by performing, reduces the amount of oxides contained in the final sintered pure coating the steel sheet surface conditioning step, it is possible to reduce the load for removing the finished sintered pure film.
[0128]
　7. Steel sheet surface conditioning step
　in the steel sheet surface conditioning step, the steel sheet after the finish annealing step, subjected to a surface smoothing treatment, at least one of Al and Mg in the surface of the steel sheet 0.03 ~ 2.00 g / m 2 to present to adjust to.
[0129]
　The steel sheet surface conditioning process, as core loss is preferably reduced, the steel sheet surface after finish annealing to smooth surfaces. Specifically, the steel sheet surface Ra (arithmetic mean roughness), for example, adjusted to be 1.0μm or less. Preferably 0.8μm or less, more preferably 0.6μm or less. This adjustment, iron loss can be preferably reduced.
[0130]
　The steel sheet surface conditioning process, and smooth the surface of the steel sheet after finish annealing, the surface of the steel sheet, one or both of Al and Mg is 0.03 ~ 2.00 g / m 2 is adjusted such that there. This adjustment, 0.10 ~ 1.00 g / m 2 preferably, 0.13 ~ 0.70 g / m 2 and more preferably.
[0131]
　Abundance of one or both of Al and Mg is 0.03 g / m 2 by weight, the thickness of the compound layer, one third of the thickness of the insulating coating, or may exceed 0.5 [mu] m, the thickness of the Cr-depleted zone, one third of the thickness of the insulating film, or may exceed the 0.5 [mu] m. Therefore, since there may not be ensured water resistance of the insulating coating, the presence of one or both of Al and Mg is 0.03 g / m 2 and more.
[0132]
　On the other hand, the abundance of one or both of Al and Mg is 2.00 g / m 2 by weight, in the intermediate layer forming step of the steel sheet surface after the steel sheet surface conditioning step, oxidation progresses locally, intermediate layer the interface of the base material steel plate is deteriorated and the irregularities there is a possibility that the iron loss is deteriorated with. Therefore, the presence of one or both of Al and Mg is 2.00 g / m 2 or less.
[0133]
　Steel sheet surface conditioning step is roughly divided in the case of irregularities on the interface between the finish annealing film and the base steel sheet is formed, and when unevenness in the interface between the finish annealing film and the base steel sheet not formed. Hereinafter, for each case it will be described.
[0134]
　Here, the "case where irregularities on the interface between the finish annealing film and the base steel sheet is formed", as in the conventional oriented electrical steel sheet forsterite film is formed as the annealing film finishing, finishing annealing film at the interface between the base steel sheet, irregularities in the form of so-called "root", are formed to a deep position of the base material steel plate inner, result means if the iron loss is not preferable reduced. Specifically, the base material steel plate surface Ra (arithmetic mean roughness), for example, refers to a case where more than 1.0 .mu.m.
[0135]
　The "if irregularities on the interface between the finish annealing film and the base steel sheet is not formed" literally means when unevenness on the interface between the finish annealing film and the base steel sheet not formed. Specifically, the base material steel plate surface Ra (arithmetic mean roughness), for example, refers to the case where 1.0μm or less.
[0136]
　(1) When the interface irregularities are formed between the finish annealing film and the base steel sheet
　if the interface to the unevenness of the finish annealing film and the base steel sheet is formed, in order to preferably reduce iron loss, the steel sheet surface control in step, to remove any finish sintered pure film from the steel sheet surface after finish annealing, to adjust the surface of the steel sheet smooth surface.
[0137]
　After adjusting the base steel sheet surface to the smooth surface, the base material the method of applying a solution or the like containing Al and / or Mg on the surface of the steel sheet, the metal elements Al and / or Mg in the base steel sheet surface and / or oxides method of depositing or thermal spraying as compounds such as the base material by a method such as plating the Al and / or Mg as a pure metal and / or alloy on the surface of the steel sheet, - one or both of 0.03 of Al and Mg in the steel sheet surface 2 .00G / m 2 adjusted to such that there.
[0138]
　These methods, when adjusting the abundance of Al and / or Mg present in the steel sheet surface, the total amount of Al and / or Mg, the amount of coating, the adhesion amount of vapor deposition or thermal spraying, or can be calculated from the coating weight .
[0139]
　How to remove all finished sintered pure coating, for example, pickling, and carefully removed with a means of grinding or the like, a method of the base steel sheet to expose is preferred. How to make the surface of the steel sheet smooth surface, for example, a method of smoothing the base material steel plate surface by chemical polishing or electrolytic polishing is preferable. These regarded as surface smoothing treatment.
[0140]
　(2) finish annealing film and the base material when the interface irregularities are not formed of the steel sheet
　if the interface to the unevenness of the finish annealing film and the base steel sheet is not formed, the steel sheet surface conditioning step, the (a) finish sintered pure film, annealing separator containing Al and Mg, and / or, in the case that contains the reaction product containing Al and Mg, annealing separator containing (b) to finish sintered pure film, Al and Mg, and / or, it is divided into the case does not contain the reaction product containing Al and Mg. Hereinafter, for each case it will be described.
[0141]
　(A) the finished sintered pure coating annealing separator containing Al and / or Mg, and / or, if include reaction products containing Al and / or Mg
　finishing sintered pure film, Al or Mg annealing separator containing, and / or, if it contains a reaction product containing Al and Mg, in the steel sheet surface conditioning step, deliberately leaving a portion of the finishing sintered pure coating of the steel sheet surface, the steel sheet surface adjusted to smooth surface.
[0142]
　Some finishing sintered pure film intentionally allowed to remain, and the amount of oxygen finish annealing film be left contains the 0.05 ~ 1.50 g / m 2 is controlled so that, Al and the surface of the steel sheet one or both of Mg is 0.03 ~ 2.00 g / m 2 can be adjusted so that there.
[0143]
　Controlled by, the steel sheet surface which is necessary when forming the intermediate layer Al and / or Mg is supplied from the finish sintered pure coating of, and one or both of Al and Mg in the steel sheet surface is 0.03 ~ 2.00 g / m 2 can be adjusted so that there. In this case, the total amount of it is required to be present on the surface of the steel sheet Al and / or Mg, is adjusted by replacing the amount of oxygen contained in the finish annealing film to remain.
[0144]
　The amount of oxygen finish annealing film be left contains the 0.12 ~ 0.70 g / m 2 was controlled to be, one or both of Al and / or Mg on the surface of the steel sheet is 0.10 ~ 1.00 g / m 2 is preferably adjusted so that there. The amount of oxygen finish annealing film be left contains the 0.17 ~ 0.35 g / m 2 in the control so as to be, one or both of Al and Mg in the steel sheet surface is 0.13 ~ 0.70 g / m 2 there it is more preferable to adjust to.
[0145]
　When the finish annealing film which residual oxygen is less contained, it may not be possible to ensure the water resistance of the insulating coating. When the oxygen amount of the many, the intermediate layer becomes thicker, the space factor when using the iron core may be reduced. When the oxygen amount of the is excessive, it becomes difficult to maintain a uniform formation reaction of the intermediate layer, the progress of local oxidation occurs, the interface between the intermediate layer and the base material steel plate becomes uneven, iron loss may be deteriorated.
[0146]
　Incidentally, intentionally leaving a part of the finished sintered pure coating of steel surfaces, one or both of Al and Mg in the steel sheet surface is 0.03 ~ 2.00 g / m 2 when adjusted to present, residual the amount of oxygen finish annealing film which contains, or, the total amount of Al and / or Mg present in the steel sheet surface may be determined as follows. By analyzing the steel sheet leaving a finish annealing film, the steel plate 1 m 2 the amount of oxygen present per, or to determine the total amount of Al and Mg. Further, by analyzing the steel sheet to remove any finish annealing film (base material steel plate), the steel plate 1 m 2 the amount of oxygen present per, or to determine the total amount of Al and Mg. From the difference between these two analysis results may be obtained the desired value.
[0147]
　Method of leaving a part of the finished sintered pure coating, for example, as to leave a part of the finished sintered pure film, pickling may be performed grinding or the like. This regarded as surface smoothing treatment.
[0148]
　(B) the finished sintered pure coating annealing separator containing Al and / or Mg, and / or, if not included reaction products containing Al and / or Mg
　finishing sintered pure film, Al or Mg annealing separator containing, and / or, if not included reaction products containing Al and Mg, because finishing sintered pure coating is not required, the steel sheet surface conditioning step, a finishing sintered pure film from the steel sheet surface all were removed, to adjust the surface of the steel sheet smooth surface.
[0149]
　After removing all the finishing sintered pure film, one or both of Al and Mg in the steel sheet surface is 0.03 ~ 2.00 g / m 2 is adjusted such that there. Method of adjusting the total amount of Al and / or Mg present in the steel sheet surface, similar to the method described in the section of "(1) When the irregularities on the interface between the finish annealing film and the base steel sheet is formed" it is.
[0150]
　Further, a method of a method and the surface of the steel sheet to remove any finish sintered pure film on the smooth surface, the above-mentioned section of the "(1) When the irregularities on the interface between the finish annealing film and the base steel sheet is formed" is the same as the method.
[0151]
　(3) preferably steel sheet surface conditioning step
　described above were described in the section "(1) When the interface irregularities of the finish annealing film and the base steel sheet is formed", the total amount of Al and / or Mg present on the surface of the steel sheet how to adjust the direct, albeit simple, as electromagnetic steel plates, be incorporated into the method of manufacturing a steel sheet for continuously producing at a high speed is difficult, even if incorporated, manufacturing costs there is likely to be very high.
[0152]
　For this reason, the present inventors have conducted intensive studies, it is not difficult to incorporate the manufacturing method of the electromagnetic steel sheets, and an increase in manufacturing costs little, as a method that can be used realistically, the above "(2) when unevenness on the interface between the finish annealing film and the base steel sheet is not formed (a) finish sintered pure coating annealing separator containing Al or Mg, and / or, Al and / or Mg described in the section if it contains a reaction product containing ", I found a method of adjusting the total amount of Al and Mg that exist on the surface of the steel sheet.
[0153]
　In this way, without newly providing a special step of adjusting the total amount of Al and / or Mg present on the surface of the steel sheet, the amount of oxygen contained in the finish annealing film to residual 0.05 ~ 1.50 g / m 2 so that, by deliberately leaving a portion of the finishing sintered pure coating of steel surfaces, one or both of Al and Mg is 0.03 ~ 2.00 g / m on the surface of the steel sheet 2 such that there adjust.
[0154]
　Further, in this method, if the conventional one carefully all finished sintered pure coating had to be removed, intentionally oxygen content 0.05 ~ 1.50 g / m 2 the residual is thereby such that, it is possible to reduce the load of the removal of the finished sintered pure film.
[0155]
　Considering the manufacturing cost including productivity, a method of adjusting the total amount of Al and / or Mg present in the steel sheet surface, the method is preferable.
[0156]
　8. Intermediate layer forming step
　in the intermediate layer formation step, a heat treatment to the steel sheet which has passed through the steel surface conditioning step, to form an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet. In the intermediate layer forming step, the steel sheet surface-treated steel sheet that is thermally oxidized (annealing in an atmosphere having a controlled dew point), to form the intermediate layer. In the steel sheet surface conditioning step, when intentionally leaving a part of the annealing film finishing the surface of the steel sheet, the intermediate layer is formed from the reaction product produced by thermal oxidation of the finish annealing film and the base steel sheet .
[0157]
　In the steel sheet surface conditioning step, after removing all the finish annealing film of the steel sheet surface, in the case of applying a solution or the like containing Al and / or Mg on the surface of the steel sheet, Al and / or Mg metal elements and / or oxides when depositing or thermal spraying as compounds such or, in the case of plating the Al and / or Mg as a pure metal and / or alloy, coating material, the deposited material of the vapor deposition or thermal spraying, plating materials, and / or, the base material intermediate layer is formed from a reaction product formed by thermal oxidation of the steel sheet.
[0158]
　In the intermediate layer forming step, the heat treatment in the steel sheet after the steel sheet surface conditioning step, one or both of Al and Mg in the surface of the steel sheet 0.03 ~ 2.00 g / m 2 to be subjected to a heat treatment in the presence Become. The total amount of Al and / or Mg present on the surface of the steel sheet is 0.03 g / m 2 by at least, it is possible to ensure water resistance of the insulating coating. The total amount of Al and / or Mg present on the surface of the steel sheet is 2.00 g / m 2 by at most, the intermediate layer is ensured adhesion between the base steel sheet and the insulating film, and was adjusted to the smooth surface It can be avoided that the surface of the steel sheet deteriorates to irregularities.
[0159]
　For the same reason, one or both of Al and Mg is 0.10 ~ 1.00 g / m on the surface of the steel sheet 2 is preferably subjected to a heat treatment in the presence, either or both of Al and Mg in the steel sheet surface 0. 13 ~ 0.70 g / m 2 and more preferably subjected to heat treatment in the presence.
[0160]
　Why can secure water resistance of the insulating film by applying the heat treatment is not clear, Al and / or Mg is incorporated into the intermediate layer, the intermediate layer is considered to be because the modified.
[0161]
　Be an intermediate layer of the same thickness, in the intermediate layer which is not Al and / or Mg is incorporated, easily diffused Fe, whereas, in the intermediate layer is Al and / or Mg is incorporated, Fe is difficult to spread. Therefore, by Al and / or Mg is incorporated into the intermediate layer, the intermediate layer is reformed, diffusing from the base material steel plate of Fe into the insulating film is suppressed, it is considered to improve the water resistance of the insulation coating .
[0162]
　Intermediate layer is preferably formed to a thickness in the item of the "A. oriented electrical steel sheet 1. intermediate layer." The intermediate layer, as described above, and the reaction product formed by thermal oxidation of the finish annealing film and the base steel sheet, the coating material, the deposited material, plating materials, and / or generated by thermal oxidation of the base material steel plate It formed from the reaction product. Therefore, and if the finish annealing film remaining amount of oxygen often contain, coating materials, if the deposited material, and / or the plating material is the total amount of Al and / or Mg often contain an intermediate layer is formed thickly easy.
[0163]
　Conditions of the heat treatment is not particularly limited, from the viewpoint of forming the intermediate layer to a thickness of 2 ~ 400 nm, preferably be held in a temperature range of 300 ~ 1150 ℃ 5 ~ 120 seconds, a temperature of 600 ~ 1150 ° C. it is more preferably maintained in range 10 to 60 seconds.
[0164]
　From the viewpoint of not oxidized inside the steel sheet, the atmosphere during heating and during the temperature holding annealing is preferably a reducing atmosphere. Nitrogen mixed with hydrogen being more preferred. Nitrogen mixed with hydrogen, for example, hydrogen 50 to 80 vol% and the balance consists of nitrogen and impurities, dew point: Preferably atmosphere -20 ~ 2 ° C.. Among them, a hydrogen: 10-35 vol%, the balance consists of nitrogen and impurities, dew point: Preferably atmosphere -10 ~ 0 ° C..
[0165]
　In the intermediate layer forming step, dew point: -20 ~ at 0 ℃ atmosphere, and held in a temperature range of 600 - 1150 ° C. 10 ~ 60 seconds, is preferably subjected to heat treatment steel. Otherwise atmosphere, the oxidation reaction is inside oxidized, intermediate layer and the unevenness of the interface between the base steel sheet may be prominently iron loss may deteriorate.
[0166]
　From the viewpoint of the reaction rate, although the heat treatment temperature is preferably at least 600 ° C., exceeding 1150 ° C., it becomes difficult to maintain the formation reaction of the intermediate layer uniformly, unevenness of the interface between the intermediate layer and the base steel sheet is conspicuous It made iron loss and may deteriorate. In addition, decreases the strength of the steel sheet, it is difficult to process in the continuous annealing furnace, the productivity may decrease. Retention time, depending on the mood and the holding temperature conditions, from the viewpoint of forming the intermediate layer, preferably at least 10 seconds, reduced productivity, and a reduction in space factor due to the thickness of the intermediate layer becomes thicker with a view to avoiding, preferably 60 seconds or less.
[0167]
　9. Insulating film formation step
　in the insulating film forming step, the steel sheet through the intermediate layer forming step, and baking by applying an insulating film-forming solution containing Cr as a main component phosphate and colloidal silica, the insulating film on the surface of the steel sheet to form.
[0168]
　The insulating film formation step, the surface of the intermediate layer, phosphoric acid or phosphate, colloidal silica, and co comprising chromic anhydride or chromium salt - baked by applying a coating solution to form an insulating coating. Phosphates, for example, Ca, Al, Mg, phosphates Sr and the like are preferable. Chromates, for example, Na, K, Ca, chromic acid salts Sr and the like are preferable. Colloidal silica is not particularly limited, and various particle sizes may be used. Co - The coating solution, in order to improve various characteristics of the present invention electrical steel sheet, the various elements or compounds may be added.
[0169]
　Insulating coating is preferably formed to a thickness in the item of the "A. oriented electrical steel sheet 2. insulating film (4) all of the insulating film." Baking conditions of the insulating coating can be a typical baking conditions, for example, hydrogen, water vapor, and consists of nitrogen, the oxidation degree (P H2 O / P H2 ): In an atmosphere of 0.001-1.0, 300 preferably maintained at a temperature range of ~ 1150 ℃ 5 ~ 300 seconds.
[0170]
　The insulating film formation step, the surface of the intermediate layer, phosphoric acid or phosphate, chromic acid or chromates, and co including colloidal silica - coating solution was applied and the degree of oxidation (P H2 O / P H2 ): 0 in an atmosphere of .001 to 0.1, more preferably baked and held in a temperature range of 300 - 900 ° C. 10 ~ 300 seconds. And the degree of oxidation less than 0.001, liable to crystalline phosphides decompose the phosphate is formed, there are cases where water resistance of the insulation coating is deteriorated. And the degree of oxidation is greater than 0.1, tends to proceed the oxidation of the steel sheet, there is a case where iron loss is reduced oxides of internal oxidation type is generated.
[0171]
　Baking conditions themselves, the present invention production process is not specific special baking conditions. However, in the present invention production process, since the inseparably control each step can be suppressed Fe from the base steel sheet to insulating coating upon heating for baking is diffused.
[0172]
　The insulating film forming step, after baking, as the insulating film and the intermediate layer does not change, in an atmosphere that was maintained low degree of oxidation, it is preferable to cool the steel plate. Cooling conditions may be a general cooling conditions, for example, hydrogen: 75 vol% and the balance consists of nitrogen and impurities, dew point: 5 ~ 10 ° C. and the oxidation degree (P H2 O / P H2 ): less than 0.01 preferably cooled in the atmosphere.
[0173]
　Cooling conditions, in an atmosphere at the time of cooling from the holding temperature at the time of baking to 500 ° C., preferably lower than when baking the degree of oxidation. For example, the hydrogen: 75 vol% and the balance consists of nitrogen and impurities, dew point: 5 ~ 10 ° C. and the oxidation degree (P H2 O / P H2 ): it is preferable 0.0010 to cool in an atmosphere of ~ 0.0015.
[0174]
　10. Preferred present invention production process
　in the manufacturing method of the present invention, in consideration of the manufacturing cost including productivity, a method of adjusting the total amount of Al and / or Mg present in the steel sheet surface, the "7 steel surface conditioning step ( 2) the interface if the irregularities are not formed in (a) finish sintered pure film of the finish annealing film and the base steel sheet, annealing separator containing Al and / or Mg, and / or the content of Al and / or Mg the method described in the section of the case "that contains the reaction product is preferable.
[0175]
　To use this method, the conditions to finishing annealing step (e.g., the coating amount of the annealing separating agent) to adjust the annealing separating agent contained in the final sintered pure film, and / or contained in the reaction product the total amount of Al and Mg may suppress the. Thus, it is possible to reduce the load of the removal of the finished sintered pure film.
[0176]
　The present invention production process may further include a common process. For example, during the period from the start of the decarburization annealing to the expression of secondary recrystallization in finish annealing may further comprise a nitriding treatment step for increasing the N content of the decarburization annealed steel sheet. In this case, even small temperature gradients to be applied to steel sheet boundary portion of the primary recrystallization region and the secondary recrystallization region, it can be stably improved magnetic flux density.
[0177]
　Nitriding can be a general nitriding. For example, processing for annealing in an atmosphere containing a gas with a nitriding ability such as ammonia, processing for annealing finishing decarburization annealed steel sheets where the annealing separator coating containing powder with a nitriding capability such as MnN is preferred.
[0178]
　Each layer of the present invention electrical steel sheet is observed as follows, measured.
[0179]
　Test pieces were cut out from the oriented electrical steel sheet having an insulating film, a film structure of the test piece, transmission electron microscope observation with (TEM Transmission Electron Microscope).
[0180]
　Specifically, the cut surface was cut out by FIB (Focused Ion Beam) processing so that the thickness direction and parallel to and rolling direction and perpendicular, the cross-sectional structure of the cut surface, each layer in the observation field observed by STEM (Scanning-TEM) at a magnification enters to (bright-field image). If during the observation field of view from entering each layer, observing a cross section structure in successive multiple field-of-view.
[0181]
　To identify each of the cross-sectional structure, using the TEM-EDS (Energy Dispersive X-ray Spectroscopy), perform line analysis along a thickness direction, a quantitative analysis of chemical components of each layer. Element for quantitatively analyzing is Fe, P, Si, O, Mg, and 6 elements Cr. Further, the particular compound layer, combined with EDS, performs identification of the crystal phase by electron diffraction.
[0182]
　Bright field image observation in TEM described above, quantitative analysis of TEM-EDS, the electron diffraction results, and identifying the respective layers, the measurement of the thickness of each layer. Incidentally, the specific subsequent layers, measurement of the thickness is carried out in the same scanning line all the same sample.
[0183]
　Regions Fe content is 80 atomic% or more is judged to be the base steel sheet.
[0184]
　Fe content is less than 80 atomic%, P content is 5 atomic% or more, Si content of less than 20 atomic%, O content of 50 atomic% or more, the insulating regions Mg content is 10 atomic% or less coating it is determined that the (Cr-deficient layer and comprising a composition variation layer of compound layer).
[0185]
　Fe content is less than 80 atomic%, less than the P content of 5 atomic%, Si content is 20 atomic% or more, O content is 50 atomic% or more, the intermediate regions Mg content satisfies 10 at% it is determined that the layer.
[0186]
　Judging by the component layers as described above, areas where none of the compositional analysis (blank area) may occur.
　However, in the present invention electrical steel sheet, the base steel sheet, intermediate layer, and identifying the respective layers so that the three-layer structure of the insulating film (including a composition fluctuation layer). Its criteria are as follows. Blank area between the first and the base steel sheet and the intermediate layer as a boundary to the center of the blank area, the base material steel plate side base material steel plate, the intermediate layer side is considered as an intermediate layer. Then the blank area between the insulating film and the intermediate layer as a boundary to the center of the blank area, the insulating film side insulating film, the intermediate layer side is considered as an intermediate layer. Blank area between then and the base steel sheet and the insulating coating, as a boundary the center of the blank area, the base material steel plate side base steel sheet, the insulating film side is considered insulating coating. Then between the intermediate layer and the intermediate layer, the blank area, the base steel sheet, the insulating film is regarded as an intermediate layer. Then, between the base steel sheet and the base steel sheet, a blank area, the insulating coating is regarded as the base steel sheet. Then, between the insulating film and the insulating film, the blank area is regarded as an insulating film.
　This procedure, the base material steel plate is separated into insulating film and the intermediate layer.
[0187]
　Next, the compound layer to confirm whether or not present in the insulating film in specified above. Verifying whether the compound layer is present also conducted by TEM.
[0188]
　The insulating film in the observation field, performs a wide-area electron diffraction of the electron beam diameter as the smaller of 1/20 or 100nm insulating film, some or crystalline phase is present in the electron beam irradiation region the whether to confirm the electron diffraction pattern.
[0189]
　Above-mentioned when the crystalline phase in the electron diffraction pattern was confirmed to be present, check the object of the crystalline phase in the bright-field image, information with respect to the crystalline phase, the crystalline phase of the subject squeezing an electron beam so as to obtain performs electron diffraction to identify the crystal structure of the crystalline phase from the electron diffraction pattern of interest. This identification may be performed by using the ICDD (International Centre for Diffraction Data) of the PDF (Powder Diffraction File).
[0190]
　The identification of the crystalline phases as described above, the subject crystalline phase, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 or, (Fe , Cr) 2 P 2 O 7 , a whether the possible decision is.
[0191]
　Incidentally, the crystalline phase (Fe, Cr) 3 P in which one of the identification, Fe 3 of P PDF: No. 01-089-2712 or Cr 3 P of PDF: No. It may be carried out based on 03-065-1607. Crystalline phase (Fe, Cr) 2 if it were P identified, Fe 2 of P PDF: No. 01-078-6749 or Cr 2 P of the PDF: No. It may be carried out based on 00-045-1238. Crystalline phase (Fe, Cr) of identifying a P is the FeP PDF: No. 03-065-2595 or CrP of PDF: No. It may be carried out based on 03-065-1477. Crystalline phase (Fe, Cr) P 2 or identification is the, FeP 2 of PDF: No. 01-089-2261 or CrP 2 of the PDF: No. It may be carried out based on 01-071-0509. Crystalline phase (Fe, Cr) 2 P 2 O 7 if they were identified, Fe 2 P 2 O 7Of PDF: No. 01-076-1762 or Cr 2 P 2 O 7 of the PDF: No. It may be carried out based on 00-048-0598. In the case of identification based crystalline phase above the PDF, performing the identification of crystal structure as a tolerance ± 3 ° tolerance ± 5% and inter-plane angle of the surface interval.
[0192]
　From the identification results of crystal structure analysis is performed point by TEM-EDS against crystalline phase can be determined to be the same crystal structure as the crystalline phosphide above. Accordingly, the chemical components of the crystalline phase of interest is, the total content of Fe and Cr is 0.1 atomic% or more and 0.1 atomic% or more P and O, respectively, Fe, Cr, P and O the total content of 70 atomic% or more, if Si is 10 atomic% or less, it is determined that the crystalline phosphide described above.
　Point analysis by crystal structure and TEM-EDS was performed with respect to 10 pieces of the crystalline phase in a wide area electron diffraction exposure area, of which, five or more can be determined to be crystalline phosphides according the If, it is determined that the area is a compound layer.
[0193]
　Checking whether any crystalline phase in the electron beam irradiation region described above is present (the wide-area electron beam irradiation), along the thickness direction, towards the outermost surface of the interface between the insulating film and the interlayer gap sequentially performed so that no repeated until the crystalline phosphide electron beam irradiation zone is confirmed that there is no.
[0194]
　The compound layer specified above, the total length of the scanning line of the electron beam irradiation region is determined that the compound layer and the thickness of the compound layer.
[0195]
　Then, Cr-depleted zone confirms whether or not there in an insulating film specified above. Verifying whether the Cr-depleted zone is present also conducted by TEM.
[0196]
　The specified insulating coating region above and analyzed by STEM. Time of analysis, the analysis value of the void portion in the insulating film is evaluated to exclude.
[0197]
　For insulating coating region toward the outermost surface at the interface of the insulating film and the intermediate layer, Cr concentration when the quantitative analysis is continuously over 5 nm, when it becomes less than 80% of the average Cr concentration as a whole insulating film, the the region sandwiched by the first analysis point and an interface to the composition change layer. Cr-deficient layer, the composition change layer, the region excluding the compound layer.
[0198]
　The composition variation layer region is smaller than the compound layer region, it is determined that the Cr-depleted layer is not present in the insulating coating. Compositional variation layer region is greater than the compound layer region, which is referred to as Cr-depleted layer.
[0199]
　The Cr-depleted layer region specified above, the length of the scanning line and the thickness of the Cr-depleted zone.
[0200]
　Insulating film specified above, the length of the scanning line of the intermediate layer and the Cr depleted layer region, the thickness of each layer. Incidentally, when the thickness of each layer is 5nm or less, using a TEM with a spherical aberration correction function in terms of spatial resolution, analyzed along the thickness direction, to identify the respective layers. Using the TEM having spherical aberration correcting function, it is possible to EDS analysis in the spatial resolution of about 0.2 nm.
[0201]
　Or more insulating film, the intermediate layer, the measurement of the particular and the thickness of the compound layer and the Cr depleted zone, implemented seven locations in 1μm intervals with respect to the direction orthogonal to the thickness direction, the thickness of each layer in each one place the seek. Thereafter, an average value by excluding the maximum and minimum values ​​from measurements at 7 locations of a layer. This insulating coating, an intermediate layer, was performed for the compound layer and the Cr-depleted zone, the thickness of each layer.
[0202]
　Also, Ra (arithmetic average roughness) of the base material steel plate surface of the present invention electrical steel sheet is obtained by observing the vertical cross section of the tissue to the rolling direction of the steel sheet. Specifically, the position coordinates of the thickness direction of the base material steel plate surface in the cross-sectional structure of the present invention electrical steel sheet (oriented electrical steel sheet having an insulation coating and intermediate layers), measured at 0.01μm or more precision, Ra It is calculated.
[0203]
　The above measurement was continuous 0.1μm pitch in a direction parallel to the base steel sheet surface, carried out on a range (total 20000 points) over 2 mm, which is carried out at least five positions. Then, the average value of Ra calculated values ​​for each location and Ra of the base material steel plate surface. This observation, since it requires some observation magnification, observation by SEM is suitable. In addition, the measurement of the position coordinates, may be used image processing.
[0204]
　Core loss oriented electrical steel sheet (W17 / 50), the AC frequency is 50 Hz, the induced magnetic flux density is measured at 1.7 Tesla.
[0205]
　Water resistance of the coating, the plate-like test piece of 80 mm × 80 mm, after winding a round bar having a diameter of 30 mm, is submerged as it bends, evaluated by the film residual ratio after a lapse of 1 minute. Film residual rate, flat stretched test piece was flooded, the area of ​​the insulating film is not peeled off from the test piece was measured, the peeled dividing the area not in the area of ​​the steel sheet values ​​a film remaining ratio (area %) and is defined to evaluate. For example, a transparent film with a 1mm grid tick marks placed on the specimen may be calculated by measuring the area of ​​the release and non insulation coating.
Example
[0206]
　Will be further specifically described in detail the effects of an embodiment of the present invention through examples, the conditions in the examples, in one example of conditions adopted for confirming the workability and effects of the present invention There, 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, it is capable of adopting various conditions.
[0207]
　In Examples and Comparative Examples below were evaluated according to the method of observation and measurement described above.
[0208]
　(Example 1)
　in mass%, Si: 3.0%, C : 0.050%, acid-soluble Al: 0.03%, N: 0.006 %, Mn: 0.5%, and, S, and Se: to 0.01% in total, after heated 60 minutes soaking at 1150 ° C. the slab having a chemical composition the balance being Fe and impurities, subjected to hot rolling, and hot-rolled steel sheet having a thickness of 2.6mm did. The hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., and immediately cooled, and held for 120 seconds at 900 ° C., was subjected to hot rolled sheet annealing to subsequent quenching. After pickling the hot-rolled annealed sheet is subjected to cold rolling to obtain a cold-rolled steel sheet of the final sheet thickness 0.27 mm.
[0209]
　The cold-rolled steel sheet, the hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was subjected to a decarburization annealing for holding 180 seconds at 850 ° C.. The steel sheet subjected to decarburization annealing, hydrogen - nitrogen - with ammonia mixed atmosphere, subjected to nitriding annealing for holding 30 seconds at 750 ° C., was adjusted nitrogen content of the steel sheet to 230 ppm.
[0210]
　The steel sheet after nitriding annealing, alumina (Al 2 O 3 the annealing separator composed mainly of) Then, naturally cooled to obtain a steel sheet secondary recrystallization is completed.
[0211]
　The steel sheet after finish ShoJun, irregularities on the interface between the finish annealing film and the base steel sheet was formed. Specifically, Ra according base steel sheet surface after finish ShoJun is as shown in Table 1.
[0212]
　Removing a portion of the finish annealing film formed on the surface of the steel sheet, by deliberately leaving a portion of the finishing sintered pure coating on the surface of the steel sheet, as shown in Table 1, the oxygen finish annealing film remaining contains the amount was allowed to change.
[0213]
　Then, the steel sheet, hydrogen: 75 vol%, the balance consists of nitrogen and impurities, dew point: at -2 ° C. atmosphere, and held by heating to 800 ° C. at a heating rate of 10 ° C. / sec for 30 seconds, optionally, by changing the dew point of the atmosphere it was naturally cooled, to form an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet.
[0214]
　The surface of the intermediate layer, phosphates, colloidal silica, and is coated with a coating solution containing chromate, hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was heated to 850 ° C. 30 held by baking the insulating coating seconds. Subsequently, as appropriate, by changing the dew point of the atmosphere, furnace cooled 500 ° C., then allowed to cool, the steel sheet surface to form an insulating film containing Cr.
[0215]
　Note that, by heating during baking of the insulating film, the Fe from the base steel sheet to insulating coating is mixed with diffusion, structure of the insulating film is changed.
[0216]
　For the fabricated oriented electrical steel sheet, as well as evaluate the Ra of the film structure and the base steel sheet surface was evaluated and water resistance and magnetic properties. The results of the evaluation are shown in Table 1. Incidentally, finish-sintered pure coating was remaining on the surface of the steel sheet, all lost in the subsequent intermediate layer forming step process, the intermediate layer was formed directly on the base steel sheet surface.
[0217]
[Table 1]

[0218]
　As shown in Table 1, the amount of oxygen contained in the finish annealing film to remain on the surface of the steel sheet (hereinafter, referred to as "the amount of oxygen remaining finish annealing film".) Is 0.05 ~ 1.50 g / m 2 in the range of in is No. In 2-5, the thickness and the thickness of the Cr-depleted zone of the compound layer, at 1/3 or less of the thickness of the insulating film, and becomes 0.5μm or less, the higher the film residual rate, water resistance There is ensured, iron loss was lower.
[0219]
　The amount of oxygen remaining is not finished annealing film is 0.05 g / m 2 is less than No. In 1, the thickness and the thickness of the Cr-depleted zone of the compound layer, exceeds 1/3 and 0.5μm in thickness of the insulating film, the lower the film residual rate, water resistance is deteriorated. Oxygen content of the finish annealing film obtained by residual 1.50 g / m 2 greater than No. In 6 and 7, remarkably thick intermediate layer, the higher the Ra of the base material steel plate surface, the iron loss is increased.
[0220]
　Although not shown in Table 1, crystalline phosphides contained in compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 was at least one of. The average Cr concentration of the Cr-depleted zone is at atomic concentration was less than 80% of the average Cr concentration of the entire insulating film.
[0221]
　(Example 2)
　in mass%, Si: 3.5%, C : 0.070%, acid-soluble Al: 0.02%, N: 0.01 %, Mn: 1.0%, and, S, and Se: contains 0.02% in total, after heated 60 minutes soaking at 1150 ° C. the slab having a chemical composition the balance being Fe and impurities, subjected to hot rolling, and hot-rolled steel sheet having a thickness of 2.6mm did. The hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., and immediately cooled, and held for 120 seconds at 900 ° C., was subjected to hot rolled sheet annealing to subsequent quenching. After pickling the hot-rolled annealed sheet is subjected to cold rolling to obtain a cold-rolled steel sheet of the final sheet thickness 0.27 mm.
[0222]
　The cold-rolled steel sheet, the hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was subjected to a decarburization annealing for holding 180 seconds at 850 ° C.. The steel sheet subjected to decarburization annealing, hydrogen - nitrogen - with ammonia mixed atmosphere, subjected to nitriding annealing for holding 30 seconds at 750 ° C., was adjusted nitrogen content of the steel sheet to 200 ppm.
[0223]
　The steel sheet after nitriding annealing, as shown in Table 2, alumina was mixed with various weight ratios (Al 2 O 3 the annealing separator was applied to mainly magnesia (MgO)), Then, naturally cooled to obtain a steel sheet secondary recrystallization is completed.
[0224]
　Removing a portion of the finish annealing film formed on the surface of the steel sheet, by deliberately leaving a portion of the finishing sintered pure coating on the surface of the steel sheet, as shown in Table 2, oxygen finish annealing film remaining contains the amount was allowed to change.
[0225]
　Then, the steel sheet, hydrogen: 75 vol%, the balance consists of nitrogen and impurities, dew point: at -2 ° C. atmosphere, and held by heating to 900 ° C. at a heating rate of 10 ° C. / sec for 30 seconds, optionally, by changing the dew point of the atmosphere it was naturally cooled, to form an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet.
[0226]
　The surface of the intermediate layer, phosphates, colloidal silica, and is coated with a coating solution containing chromate, hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was heated to 830 ° C. 30 held by baking the insulating coating seconds. Subsequently, as appropriate, by changing the dew point of the atmosphere, furnace cooled 500 ° C., then allowed to cool, the steel sheet surface to form an insulating film containing Cr.
[0227]
　For the fabricated oriented electrical steel sheet, as well as evaluate the Ra of the film structure and the base steel sheet surface was evaluated and water resistance and magnetic properties. The results of the evaluation are shown in Table 2. Incidentally, the finished sintered pure coating not remain on the surface of the steel sheet, all lost in the subsequent intermediate layer forming step process, the base steel sheet surface, the intermediate layer was formed directly.
[0228]
[Table 2]

[0229]
　As shown in Table 2, the amount of oxygen finish annealing film obtained by residual 0.05 ~ 1.50 g / m 2 is No. In 8-14, regardless of the weight ratio of magnesia and alumina, the thickness and the thickness of the Cr-depleted zone of the compound layer, at 1/3 or less of the thickness of the insulating film, and becomes 0.5μm or less , the higher the film residual rate, water resistance is ensured, the iron loss is reduced.
[0230]
　The amount of oxygen remaining is not finished annealing film is 0.05 g / m 2 is less than No. 1 and No. In 2-7, regardless of the weight ratio of magnesia and alumina, the thickness of the thickness of the compound layer and / or Cr-depleted zone, beyond the third or 0.5μm in thickness of the insulating film, film residual the rate is low, the water resistance is deteriorated. Oxygen content of the finish annealing film obtained by residual 1.50 g / m 2 greater than No. In 15-21, remarkably thick intermediate layer, the higher the Ra of the base material steel plate surface, the iron loss is increased.
[0231]
　As shown in Table 2, No. In 1-21, regardless of the amount of oxygen in the finish annealing film obtained by residual, when the mass ratio of the magnesia is 20-50%, as compared with the case of the other mass ratio, the smaller the Ra of the base material steel plate surface , tended to iron loss is reduced.
[0232]
　Although not shown in Table 2, crystalline phosphides contained in compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 was at least one of. The average Cr concentration of the Cr-depleted zone is at atomic concentration was less than 80% of the average Cr concentration of the entire insulating film.
[0233]
　(Example 3)
　in mass%, Si: 2.7%, C : 0.070%, acid-soluble Al: 0.02%, N: 0.01 %, Mn: 1.0%, and, S, and Se: contains 0.02% in total, after heated 60 minutes soaking at 1150 ° C. the slab having a chemical composition the balance being Fe and impurities, subjected to hot rolling, and hot-rolled steel sheet having a thickness of 2.6mm did. The hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., and immediately cooled, and held for 120 seconds at 900 ° C., was subjected to hot rolled sheet annealing to subsequent quenching. After pickling the hot-rolled annealed sheet is subjected to cold rolling to obtain a cold-rolled steel sheet of the final sheet thickness 0.30 mm.
[0234]
　The cold-rolled steel sheet, the hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was subjected to a decarburization annealing for holding 180 seconds at 850 ° C.. The steel sheet subjected to decarburization annealing, hydrogen - nitrogen - with ammonia mixed atmosphere, subjected to nitriding annealing for holding 30 seconds at 750 ° C., was adjusted nitrogen content of the steel sheet to 250 ppm.
[0235]
　The steel sheet after nitriding annealing, 50%: alumina were mixed with 50% of the mass ratio (Al 2 O 3 ) and magnesia (MgO) was coated with an annealing separator consisting mainly of hydrogen - a nitrogen mixed atmosphere, after heating to 1200 ° C. at a heating rate of 15 ° C. / time, resulting in a hydrogen atmosphere, subjected to a finishing ShoJun holding at 1200 ° C. 20 h, then cooled naturally, the steel sheet secondary recrystallization is completed It was.
[0236]
　As shown in Table 3, the oxygen removing a portion of the finish annealing film formed on the surface of the steel sheet, by deliberately leaving a portion of the finishing sintered pure coating on the surface of the steel sheet, residual finish annealing film contains the amount was allowed to change. It should be noted that, in Table 3, No. While the method of removing the 5 finishing sintered pure film is "no removal", which, without removing the finished sintered pure film, means that leaving a whole finishing sintered pure coating on the surface of the steel sheet ing.
[0237]
　Then, the steel sheet, hydrogen: 75 vol%, the balance consists of nitrogen and impurities, dew point: at -2 ° C. atmosphere, was heated to 800 ° C. at a heating rate of 10 ° C. / sec and held for 60 seconds, optionally, by changing the dew point of the atmosphere it was naturally cooled, to form an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet.
[0238]
　The surface of the intermediate layer, phosphates, colloidal silica, and is coated with a coating solution containing chromate, hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was heated to 870 ° C. 60 It held, baking the insulating coating seconds. Subsequently, as appropriate, by changing the dew point of the atmosphere, furnace cooled 500 ° C., then allowed to cool, the steel sheet surface to form an insulating film containing Cr.
[0239]
　For the fabricated oriented electrical steel sheet, as well as evaluate the Ra of the film structure and the base steel sheet surface was evaluated and water resistance and magnetic properties. The results of the evaluation are shown in Table 3. Incidentally, the finished sintered pure coating not remain on the surface of the steel sheet, all lost in the subsequent intermediate layer forming step process, the base steel sheet surface, the intermediate layer was formed directly.
[0240]
[table 3]

[0241]
　As shown in Table 3, the amount of oxygen finish annealing film obtained by residual 0.05 ~ 1.50 g / m 2 in the range of No. In 1-4, regardless of the type of method for removing finishing sintered pure coating thickness and the thickness of the Cr-depleted zone of the compound layer, 1/3 or less of the thickness of the insulating film, and, 0.5 [mu] m or less becomes, the higher the film residual rate, water resistance is ensured, the iron loss was low. On the other hand, the amount of oxygen finish annealing film obtained by residual 1.50 g / m 2 greater than No. In 5, remarkably thick intermediate layer, the higher the Ra of the base material steel plate surface, the iron loss is increased.
[0242]
　Although not shown in Table 3, crystalline phosphides contained in compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 was at least one of. The average Cr concentration of the Cr-depleted zone is at atomic concentration was less than 80% of the average Cr concentration of the entire insulating film.
[0243]
　(Example 4)
　in mass%, Si: 3.3%, C : 0.070%, acid-soluble Al: 0.03%, N: 0.01 %, Mn: 0.8%, and, S, and Se: to 0.01% in total, after heated 60 minutes soaking at 1150 ° C. the slab having a chemical composition the balance being Fe and impurities, subjected to hot rolling, and hot-rolled steel sheet having a thickness of 2.6mm did. The hot-rolled steel sheet, after holding for 200 seconds at 1120 ° C., and immediately cooled, and held for 120 seconds to 900 ° C., was subjected to hot rolled sheet annealing to subsequent quenching. After pickling the hot-rolled annealed sheet is subjected to cold rolling to obtain a cold-rolled steel sheet of the final sheet thickness 0.23 mm.
[0244]
　The cold-rolled steel sheet, the hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was subjected to a decarburization annealing for holding 180 seconds at 850 ° C.. The steel sheet subjected to decarburization annealing, hydrogen - nitrogen - with ammonia mixed atmosphere, subjected to nitriding annealing for holding 30 seconds at 750 ° C., was adjusted nitrogen content of the steel sheet to 200 ppm.
[0245]
　The steel sheet after nitriding annealing, as shown in Table 4, alumina were mixed at various weight ratios (Al 2 O 3 the annealing separator was applied to mainly magnesia (MgO)),
[0246]
　In Table 4, No. 1 for - 10, oxygen to remove a portion of the finished sintered pure film formed on the surface of the steel sheet, by deliberately leaving a portion of the finishing sintered pure coating on the surface of the steel sheet, residual finish annealing film contains varying amounts, as shown in Table 4 was changed a total amount of Al and / or Mg present on the surface of the steel sheet.
[0247]
　No. For 11-13, after removing all the finishing sintered pure film, by smoothing the base steel sheet surface after finish annealing in electrolytic polishing. Specifically, Ra according base steel sheet surface after the smoothing is smoothed so that as shown in Table 4. Thereafter, the base steel sheet surface after smoothing, by electroplating Al and / or Mg as a pure metal and / or alloy, as shown in Table 4, the amount of each of Al and Mg that exist on the surface of the steel sheet It was changed.
[0248]
　Then, the steel sheet, hydrogen: 75 vol%, the balance consists of nitrogen and impurities, dew point: at -2 ° C. atmosphere, and heated to maintained for 60 seconds to 800 ° C. at a heating rate of 20 ° C. / sec, optionally, by changing the dew point of the atmosphere it was naturally cooled, to form an intermediate layer mainly composed of silicon oxide on the surface of the steel sheet.
[0249]
　The surface of the intermediate layer, phosphates, colloidal silica, and is coated with a coating solution containing chromate, hydrogen: 75 vol%, the balance in an atmosphere consisting of nitrogen and impurities, was heated to 870 ° C. 45 held by baking the insulating coating seconds. Subsequently, as appropriate, by changing the dew point of the atmosphere, furnace cooled 500 ° C., then allowed to cool, the steel sheet surface to form an insulating film containing Cr.
[0250]
　For the fabricated oriented electrical steel sheet, as well as evaluate the Ra of the film structure and the base steel sheet surface was evaluated and water resistance and magnetic properties. The results of the evaluation are shown in Table 4. Incidentally, finish-sintered pure coating was remaining on the surface of the steel sheet, all lost in the subsequent intermediate layer forming step process, the intermediate layer was formed directly on the base steel sheet surface.
[0251]
[Table 4]

[0252]
　As shown in Table 4, the total amount of Al and Mg that exist on the surface of the steel sheet (hereinafter, referred to as "the total amount of Al and Mg in the steel sheet surface.") Is 0.03 ~ 2.00 g / m 2 is No. 1 to 7 and No. In 11 to 13, regardless of the weight ratio of magnesia and alumina, the thickness and the thickness of the Cr-depleted zone of the compound layer, at 1/3 or less of the thickness of the insulating film, and becomes 0.5μm or less , the higher the film residual rate, water resistance is ensured, the iron loss is reduced.
[0253]
　The total amount of Al and Mg in the steel sheet surface is 2.00 g / m 2 No. of more than In 8 and 9, remarkably thick intermediate layer, the higher the Ra of the base material steel plate surface, the iron loss is increased. The total amount of Al and Mg in the steel sheet surface is 0.03 g / m 2 is less than No. In 10, the thickness and the thickness of the Cr-depleted zone of the compound layer, exceeds 1/3 and 0.5μm in thickness of the insulating film, the lower the film residual rate, water resistance is deteriorated.
[0254]
　Although not shown in Table 4, crystalline phosphides contained in compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 was at least one of. The average Cr concentration of the Cr-depleted zone is at atomic concentration was less than 80% of the average Cr concentration of the entire insulating film.
[0255]
　(Example 5)
　Using the same base material steel plate and the above (Example 1), and is a comparable production conditions of the above (Example 1), chromic anhydride as coating solution for forming an insulating film to produce a grain-oriented electrical steel sheet by changing the ratio. The evaluation results of these grain-oriented electrical steel sheet are shown in Table 5. No. 3-5, the thickness and the thickness of the Cr-depleted zone of the compound layer, at 1/3 or less of the thickness of the insulating film, and becomes 0.5μm or less, the higher the film residual rate, water resistance There is ensured, iron loss was lower.
[0256]
[table 5]

[0257]
　Although not shown in Table 5, crystalline phosphides contained in compound layer, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 , or (Fe, Cr) 2 P 2 O 7 was at least one of. The average Cr concentration of the Cr-depleted zone is at atomic concentration was less than 80% of the average Cr concentration of the entire insulating film.
Industrial Applicability
[0258]
　According to this aspect of the present invention, to form an intermediate layer mainly composed of silicon oxide, the interface between the base steel sheet and the coating was adjusted to a smooth surface to reduce iron loss, further containing Cr insulation in grain-oriented electrical steel sheet to form a film, it is possible to sufficiently secure the water resistance of the insulating coating, it is possible to provide an excellent grain-oriented electrical steel sheet in water resistance. Thus, there is a high availability of the industry.
DESCRIPTION OF SYMBOLS
[0259]
　1 the base steel sheet
　2A forsterite film
　2B intermediate layer
　3 insulating film
　3A compound layer
　3B Cr depleted layer
　4 crystalline phosphides

WE claims

[Requested item 1]
　A base steel sheet, and an intermediate layer disposed in contact on the base steel sheet, a grain-oriented electrical steel sheet having an insulating film serving as the intermediate layer in contact with arranged that in the uppermost surface,
　the insulating film the average of the Cr concentration is 0.1 atomic percent or more,
　when the cutting direction is viewed in cutting plane becomes parallel to the thickness direction, wherein the insulating film is, in a region in contact with on the intermediate layer, the crystalline phosphides has a compound layer containing,
　as the crystalline phosphide, (Fe, Cr) 3 P, (Fe, Cr) 2 P, (Fe, Cr) P, (Fe, Cr) P 2 or, (Fe , Cr) 2 P 2 O 7 of at least one of is included,
　when viewed in the cutting surface, the average thickness of the compound layer has a 0.5μm or less and the average thickness of the insulating film 1/3 or less
oriented electrical steel sheet, characterized in that.
[Requested item 2]
　When viewed in the cutting plane, wherein the insulating film is, in a region in contact with the compound layer has a Cr-depleted layer,
　the Cr concentration of the average Cr concentration of the Cr-depleted zone, in atomic concentration, the insulating film of less than 80%,
　the average thickness of the Cr-depleted zone is at 0.5μm or less and the one-third or less the average thickness of the insulating film
direction according to claim 1, characterized in that sex electromagnetic steel sheet.
[Requested item 3]
　When viewed in the cutting surface, the average thickness of the intermediate layer is 2 ~ 100 nm
oriented electrical steel sheet according to claim 1 or 2, characterized in that.
[Requested item 4]
　A method of manufacturing a grain-oriented electrical steel sheet according to any one of claims 1 to 3,
　heating the slab for grain oriented electrical steel sheet to 1280 ° C. or less, and the hot rolling step of performing hot rolling,
　the steel sheet having passed through the hot rolling step, the hot-rolled sheet annealing step of performing hot-rolled sheet annealing,
　subjecting the steel sheet after the hot rolled sheet annealing step, the twice or more cold rolling sandwiching once or intermediate annealing a cold rolling step,
　the steel sheet has passed the cold rolling step, the decarburization annealing step of performing decarburization annealing,
　the steel sheet which has undergone decarburization annealing step, the annealing separator application step of applying the annealing separator,
　the steel sheet having passed through the annealing separator application step, and finish annealing step of performing finish annealing,
　the steel sheet having passed through the finish annealing step, subjected to a surface smoothing treatment, at least one of Al and Mg in the surface of the steel sheet 0.03 ~ 2.00 g / m 2 steel surface conditioning engineering be adjusted to present And degree,
　the steel sheet having passed through the steel surface conditioning step, a heat treatment, an intermediate layer forming step of forming an intermediate layer on the surface of the steel sheet, and
　the steel sheet having passed through the intermediate layer forming step, a phosphate and colloidal silica and baked by applying an insulating film-forming solution containing Cr, and an insulating film forming step of the insulating film formed on the surface of the steel sheet
production method of the grain-oriented electrical steel sheet, characterized in that.
[Requested item 5]
　In the steel sheet surface conditioning step, the finish annealing step leaving a portion of the formed film, the amount of oxygen remaining film 0.05 ~ 1.50 g / m 2 is adjusted to
claim 4, characterized in that method for producing oriented electrical steel sheet according to.
[Requested item 6]
　In the intermediate layer forming step, the steel sheet has passed the steel sheet surface conditioning step, dew point: -20 ~ atmosphere of 0 ° C., the intermediate layer is subjected to heat treatment for holding at a temperature range of 600 - 1150 ° C. 10 - 60 seconds formed, then
　the the insulating film forming step, the steel sheet has passed the intermediate layer forming step, phosphoric acid or phosphate, colloidal silica, and co comprising chromic anhydride or chromium salt - applying a coating solution, forming an insulating film subjected to baking to hold 300 ~ 900 ° C. in a temperature range 10 seconds or more
manufacturing method of the grain-oriented electrical steel sheet according to claim 4 or 5, characterized in that.