JP3091088B2 - Annealing separation agent having extremely excellent reactivity and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annealing separator for producing a grain-oriented electrical steel sheet having a uniform and extremely excellent glass coating, and at the same time, obtaining a grain-oriented electrical steel sheet having excellent magnetic properties in the production of a grain-oriented electrical steel sheet. And a method for manufacturing a grain-oriented electrical steel sheet.

[0002]

2. Description of the Related Art Normally, a grain-oriented electrical steel sheet is hot-rolled from a material containing 4% or less of Si, and is subjected to annealing and cold rolling once or more than once with annealing to a final thickness. Then N ₂ +
Decarburization annealing is performed by controlling P H ₂ O / P H ₂ in an atmosphere gas such as H ₂ or H ₂ , and primary recrystallization, decarburization and formation of an oxide film mainly composed of SiO ₂ are performed. .

[0003] Thereafter, an annealing separator containing MgO as a main component is made into a slurry and applied by a coating roll or the like, and then subjected to final annealing to perform secondary recrystallization, purification, and formation of a glass film. A mold insulating coating agent is applied and baked in a continuous line to obtain a product. Furthermore, in the case of a high magnetic flux density grain-oriented electrical steel sheet, especially in a thin material having a thickness of 0.17 mm or less, a laser, a press roll,
Iron loss is improved by performing a magnetic domain refining treatment for providing linear flaws by using a tooth-shaped roll, marking, or the like.

[0004] This grain-oriented electrical steel sheet utilizes a phenomenon in which (110) <001> crystals having a <001> axis grow preferentially by high-temperature finish annealing (secondary recrystallization annealing). It has low surface energy during this secondary recrystallization process (110)
Plane crystals grow preferentially and erode other crystals whose growth is suppressed by finely dispersed AlN, MnS, etc. as inhibitors in the steel (110) <00.
1> It is considered that crystals grow preferentially. Therefore, in order to manufacture an excellent grain-oriented electrical steel sheet, it is important to control the dispersion of AlN, MnS, and the like in the steel and control the decomposition thereof. It is known that the change of the inhibitor during the final annealing is affected by the oxide film formed by the decarburizing annealing, the annealing separator, the thermal cycle of the final finishing annealing, and the atmospheric conditions. Among them, the properties and additives of MgO as an annealing separator have a great influence on the start time of glass film formation, the formation speed, the quality and quantity of the film, and the like, and thus have a great influence on the inhibitor.

The annealing separator MgO reacts with the SiO ₂ -based oxide film formed by decarburizing annealing to form a forsterite-based glass film usually called a glass film (2MgO + SiO ₂ → Mg ₂ SiO _4). ). In the case of using a conventional MgO powder in the formation of the glass film, there is a problem of the reactivity control in the formation of the glass film.
In addition to the particle size, purity, and activity, the properties of MgO, such as the dispersibility in water, the amount of hydration, the amount of application, the uniformity of the applied film, the adhesion to the steel sheet surface, etc., are large when applied to steel sheets. Further, the type and amount of the additive added as a reaction accelerator for the glass film formation and the state of dispersion on the MgO surface and the steel sheet surface affect the film formation start temperature, the formation speed, the formation amount, and the like. . These differences in the various MgO properties of the annealing separator result in determining not only the coating properties but also the magnetic properties of the final product.

In general, MgO used as an annealing separator is prepared by adjusting a raw material such as magnesium hydroxide, magnesium carbonate, basic magnesium carbonate or the like to fine-particle crystals having an average particle size of about several hundreds to several thousand angstroms. , 7
Baking at a high temperature of about 00 to 1200 ° C and 0.2 to 5 μm
MgO fine crystal particles are obtained and used. Usually, this MgO is blended with various additives as a reaction accelerator at the time of glass formation as needed, suspended in water to form a slurry, and placed in a tank equipped with a propeller-like, shear-like, or other stirring device. After stirring and dispersing, it is applied to a steel plate surface by a rubber roll or the like and dried.

[0007] At this time, MgO and additives are aggregated due to temporal change due to moisture absorption during storage from sintering and baking in the manufacturing stage to use stage, and strong agglutination reaction between particles in the stage of being suspended in water. In the stage of being applied to the steel plate surface,
The particles become coarse particles of several microns to several tens of microns and cause a decrease in reactivity. In particular, in the case of conventional MgO, in order to obtain low hydrated MgO, production at high temperature is indispensable. In such a case, reactions such as sintering and aggregation of MgO are further strengthened. For this reason, on the steel sheet surface after coating and drying, a reduction in the contact area of the MgO particles, a reduction in the coating film density, a reduction in the adhesion to the steel sheet surface, a reduction in the uniformity of the coating film, and the like occur.

Further, in such a case, the viscosity of the slurry is reduced, the workability of high-speed coating is deteriorated, and uniform coating becomes extremely difficult. Also, when an additive is added to MgO as a reaction accelerator for a glass coating, the additive itself also undergoes sintering during production and agglomeration in the slurry, resulting in coarse particles in the coating film or in the steel sheet. Present on the oxide film.
In particular, when added to MgO having strong cohesiveness of MgO itself, this phenomenon becomes more remarkable. As a result, the reaction promoting effect is weakened or a non-uniform reaction occurs, so that it is difficult to obtain a uniform and good glass coating, thereby deteriorating magnetic properties. From such a problem, development of an annealing separator having good dispersibility, fine particles and good reactivity is an important subject.

As a technique for producing an annealing separator MgO having excellent reactivity, Japanese Patent Laid-Open No. 156226/1987 proposes a method of activating the outermost surface layer of MgO particles by the present inventors. In this method, only the outermost layer of the MgO particles obtained by firing at a high temperature is subjected to the hydration layer M
It forms g (OH) ₂ , improving the uniformity of the glass coating and improving the magnetic properties. In Japanese Patent Application Laid-Open No. 2-267278, baked MgO is
After passing through an atmosphere containing water vapor of 0 ° C. or more, an annealing separator containing MgO, in which an OH chemically adsorbed layer is formed on the MgO surface in an amount of 0.8 to 2.5% based on the amount of MgO in terms of H ₂ O, is decarburized. A technique has been proposed because it is applied to a later steel sheet and finish annealing is performed. It is described that a grain-oriented electrical steel sheet having a uniform glass coating and having excellent magnetic properties is thereby obtained.

Japanese Patent Application Laid-Open No. Hei 5-247661 discloses a method for producing a grain-oriented electrical steel sheet having a uniform glass coating and excellent magnetic properties, in which a certain amount of sulfur is removed in a decarburizing annealing step.
There has been proposed a method in which an iO ₂ layer is formed, and a slurry fine particle dispersing device is used to perform ultra-fine atomization of the slurry and activation treatment of the particle surface when applying the annealing separator slurry. All of these technologies solve the agglomeration of MgO particles during the application of the annealing separator by modifying the surface of MgO after annealing by special surface treatment at high temperature or by atomizing by ultra-fine dispersion technology. And surface modification, thereby lowering surface energy, improving compatibility with water, and at the same time, improving the forsterite formation reaction by a certain amount of OH layer formed on the surface layer of MgO particles. Things. Due to this effect, it is applied in a state of better dispersion on the steel sheet surface than conventional MgO, and a considerable improvement effect is obtained in the formation of a glass film. However, the sintering resulting from the MgO production conditions, the stability of the OH chemisorption layer,
Problems such as agglomeration due to changes over time from the production of MgO to its use have not been completely solved, and there remains a problem that troubles in the film and magnetic properties cannot be avoided depending on the quality of the oxide film formed in the decarburization annealing. For this reason, further development and improvement of MgO having lower hydration and higher reactivity is desired.

[0011]

SUMMARY OF THE INVENTION In the present invention, a new annealing method is used to apply the annealing separating agent during the production of grain-oriented electrical steel sheets, by improving the reactivity of the conventional MgO glass film and limiting the lowering of the melting point. The solution is achieved by applying a separating agent. At this time, as MgO, M
By using a complex MgO compound in which a part of the Mg element of gO is solid-displaced by a certain amount by divalent and trivalent Fe, and further divalent and trivalent metals are substituted and dissolved, a low water content is obtained. A significant lowering of the melting point can be obtained by the sum, and the improvement is achieved by lowering the temperature of the glass film formation in the finish annealing and by making it uniform and stable.
This enables the formation of a good glass film with good film tension, adhesion, uniformity, etc., as well as an excellent surface sealing effect by the film, stabilization of the inhibitor, and at the same time annealing separation for obtaining good magnetic properties. The object is to provide an agent and a method for producing a grain-oriented electrical steel sheet using the same.

[0012]

Means for Solving the Problems In the glass coating forming process from the decarburizing annealing to the final finishing annealing process of the grain-oriented electrical steel sheet, the present inventors produce a product having a uniform glass coating and excellent magnetic properties. The method was discussed. In this study, the research was conducted with a focus on improving the reactivity of MgO used as an annealing separator. As the annealing separator,
Usually, MgO and an additive such as a Ti compound are used as a reaction accelerator. In such prior art, Mg
Only the properties of O affect the formation of the glass film, mainly the reactivity and stability of the film, and have a great effect not only on the film but also on the magnetic properties. Therefore, the auxiliary effect of the additive is rather important. It is.

The present inventors have conducted enormous research and experiments on the conversion of MgO into a solid solution type composite metal oxide as a novel low hydration highly reactive annealing separator. As a result, as a novel annealing separator which solves the above-mentioned problem, a solid solution type composite in which a certain amount of divalent or trivalent Fe and a divalent and / or trivalent metal element are substituted for a part of Mg of MgO. A new composition of MgO annealing separator has been developed. As a result, the melting point of the MgO material in the production of a grain-oriented electrical steel sheet was significantly reduced, and the formation temperature of the glass film was significantly reduced and the reaction was uniformly stabilized. As a result, an oxide film is formed under decarburizing annealing and finish annealing conditions, and an excellent glass film is formed under a wide range of glass film forming conditions. This has led to the development of a technology that can achieve a magnetic improvement effect.

Next, the novel solid solution type composite M of the present invention
A typical production method of a gO compound and reasons for improving the reactivity will be described. The composite metal oxide of the present invention comprises [Mg _1-x X ^a _x1
^Xb _x2 ] O.Ay contains at least 0.01 to 0.20 of Fe ²⁺ and / or Fe ³⁺ as a composite solid solution metal of Mg of MgO represented by the general formula The present invention relates to an annealing separator for grain-oriented electrical steel sheets, which is characterized by dissolving a monovalent and / or trivalent metal in a solid solution and having extremely excellent reactivity. X ^a ; Fe ²⁺ and / or Fe ³⁺ X ^b ; M ²⁺ and / or M ³⁺ M ²⁺ ; Be, Ca, Ba, Sr, Sn, Mn, Co, N
i, Cu, Zn or other divalent metal M ³⁺ ; Al, Cr, Co, B, Ti, Sb or other trivalent metal A; F, Cl, Br, CO ₃ , SiO ₃ , PO ₃ , C
One or more of rO ₃ 0.01 ≦ x1 + x2 ≦ 0.40 (provided that 0.01 ≦ x1 ≦
0.20) 0.001 ≦ y ≦ 2.0 (ratio to 100 parts by weight of composite metal oxide)

In the production of this composite oxide, for example, first, the crystal structure is composed of a positively charged basic layer similar to brucite [Mg (OH) ₂ ] and a negatively charged intermediate layer composed of anions and interlayer water. Build a layered structure. In this case, the positive charge amount is determined depending on the substitution amount. This positive charge is neutralized by anions in the intermediate layer to maintain electrical neutralization of the entire crystal. The remaining space occupied by anions in the middle layer is filled with interlayer water. The production of this composite metal hydroxide is carried out, for example, using M ²⁺ , M ³⁺ and A ^{n−
(OH -, F -, Cl} -, Br -, CO 3 -, S
O ₄ ⁻ , SiO ₃ ⁻ , HPO ₄ ²⁻ , CrO ₄ ²⁻ , Fe
(CN) ₆ ^3- )), add alkali to the mixture, and adjust the pH to 7
It is obtained by a method of reacting while keeping the above. Thereafter, the composite metal hydroxide material is fired in a rotary kiln, a batch furnace, or the like at a high temperature of about 700 to 1000 ° C. for a controlled time and the like to obtain a composite metal oxide.

The composite metal oxide produced in this manner has the effect of lowering the melting point of the solid solution substance and the anion substance added as necessary is left in an appropriate amount in the final composite metal oxide product depending on the processing conditions. Can be.
For this reason, the lowering of the melting point of the Fe-containing composite metal oxide and the lowering of the melting point of the anion substance (Ay) left in an appropriate amount act synergistically, so that the conventional MgO single oxide substance or oxide mixed High reactivity that cannot be obtained with body substances is obtained. For this reason, when the temperature of the finish annealing is increased, the formation of the glass film starts at a remarkably low temperature side, and the instability of AlN, MnS, and the like due to the atmospheric gas is prevented. In addition, the inhibitory phenomenon due to the uniform glassy coating is suppressed, and a crystal structure having a good orientation can be obtained. Furthermore, a high-strength coating film with uniform and good adhesion is also formed on the finally formed glass coating film, and extremely good iron loss characteristics can be obtained by a synergistic effect with the increase in the magnetic flux density.

Next, the reasons for limitation of the present invention will be described.
TECHNICAL FIELD The present invention relates to a novel annealing separator applied when applying an annealing separator to the surface of a steel sheet after decarburizing annealing in the production of a grain-oriented electrical steel sheet. In the present invention, a part of Mg of MgO used for the annealing separator is 0.01 to 0.1%.
The most characteristic feature of the present invention is a solid-solution type composite metal oxide in which Fe of 20 is replaced with another metal element and the total amount thereof is in the range of 0.01 to 0.40. By the way, a remarkable improvement in reactivity is obtained. Form of the oxide, ^{_{[Mg 1-x X a x1 X}} b x2 ] O
-It is represented by the general formula of Ay. That is, a part of Mg of MgO is at least 0.01% by divalent and / or trivalent Fe.
Is a composite metal oxide which is substituted at a rate of about 0.20 and further substituted with other M ²⁺ and M ³⁺ to form a solid solution with a total amount of Mg in the range of 0.01 to 0.4. Features.

The divalent and trivalent substituted metal elements other than Fe at this time are represented as follows. X ^a ; Fe ²⁺ and / or Fe ³⁺ X ^b ; M ²⁺ and / or M ³⁺ M ²⁺ ; Be, Ca, Ba, Sr, Sn, Mn, Co, N
i, a divalent metal such as Cu and Zn; M ³⁺ ; a trivalent metal such as Al, Cr, Co, B, Ti, and Sb A; F, Cl, Br, CO ₃ , SiO ₃ , PO ₃ , and C
One or more of rO ₃ 0.01 ≦ x1 + x2 ≦ 0.40 (provided that 0.01 ≦ x1 ≦
0.20) 0.001 ≦ y ≦ 2.0 (ratio to 100 parts by weight of composite metal oxide)

The solid-solution type composite oxide of a divalent or trivalent metal in the present invention also includes a composite metal oxide containing two or more of the above-mentioned M ²⁺ and M ³⁺ elements in MgO. In the present invention, Fe ²⁺ and / or Fe ³⁺ are contained in an amount of 0.01 to 0.1.
It is important to include 20. When Fe is dissolved in MgO, a remarkable effect of improving the reactivity which is not seen in other metal elements is produced. This is because F in the oxide film during decarburization annealing
This is because, as in the case where the e compound improves the reactivity of the oxide film with MgO, a more remarkable effect of improving the reactivity is produced by the solid solution of Fe into MgO. Fe ²⁺ and / or Fe
^{When 3+} is 0.01 or less, the reactivity effect is small even with the solid solution effect of the present invention. On the other hand, if it is 0.20 or more, the amount is too large than the optimum amount for improving the reactivity, and depending on the conditions of the finish annealing, a coating defect in a peroxide state may occur, which is not preferable.

The metal substituted and dissolved together with Fe is the above-mentioned M
²⁺ and M ³⁺ . These appropriate amounts of substituted solid solutions are
Although the effect is not so remarkable as when the solid solution of e is substituted, all of them bring a considerable effect of improving the reactivity. The compounding amount is 0.01 ≦ X ≦ 0.40, 0.01 ≦ x1 ≦ 0.20 X = x1 + x2, x2; M ²⁺ , M other than Fe ²⁺ , Fe ³⁺
One or more of ³⁺ . If the substitution ratio is more than 0.4 in total with Fe, it is not preferable because film defects occur for the same reason as when more than 0.20 is substituted for Fe.

Next, the anionic substance remaining for the purpose of further improving the reactivity is A; F, Cl, Br, CO ₃ , S
One or more of iO ₃ , PO ₃ , CrO _3, etc., and 0.001 ≦ y ≦ 2.0 (ratio to 100 parts by weight of the composite metal oxide). If the y content is less than 0.001, little effect is exhibited. On the other hand, when it is 2.0 or more, it is likely that film defects peculiar to excessive oxidation such as shimofuri and scale are likely to occur, and not only cannot stable film characteristics be obtained in final annealing, but also magnetic characteristics may be deteriorated. Absent. In the present invention, if the composite metal oxide is adjusted within the above range, an extremely large effect of lowering the melting point can be obtained as compared with MgO alone as a base.

Next, the Fe-containing solid solution type composite metal oxide of the present invention is characterized by a surface area and an activity (CAA) to be adjusted by reducing the particle diameter. The composite oxide produced by the process of the present invention is characterized in that an extremely fine oxide can be obtained, particularly in the case of an Fe solid solution Mg compound.
In the case of an annealing separator made of ordinary MgO material, 10 to 20
Only a specific surface area of about m ² / g can be obtained. However, the present invention is characterized in that a Mg compound having a remarkably large specific surface area, which cannot be obtained with conventional MgO, is obtained.
Thereby, the reactivity in forming the glass film is further improved, and a grain-oriented electrical steel sheet having extremely excellent film and magnetic properties can be obtained.

It is desirable that the specific surface area is in the range of 15 to ²⁰⁰ m ² because the effect can be sufficiently exhibited. According to the present invention, an ultrafine Fe-containing composite oxide of 30 to 200 m ² can be easily obtained. If the specific surface area is smaller than the limited range of 15 m ^{2, the} effect of improving the reactivity is reduced, which is not preferable. On the other hand, if an attempt is made to obtain a particle having an ultrafine particle size of more than 200 m ² , it becomes difficult to produce a stable product industrially, and coagulation at the time of slurry preparation tends to occur. It is not desirable because it becomes difficult to control the amount of hydration.

The CAA value is desirably 30 to 100 seconds. Adjustment of the activity is also important for the Mg composite metal oxide of the present invention. If the CAA value is less than 30 seconds, the control of the hydration amount and the control of cohesiveness become difficult similarly to the case where the particle specific surface area is large, which is not desirable. On the other hand, if it exceeds 100 seconds, even in the highly reactive composite oxide of the present invention, a decrease in reactivity is inevitable, and sintering during firing, stable glass film formation, and a surface sealing effect cannot be obtained, which is not desirable.

Next, when the composite metal oxide of the present invention is used as an annealing separator for grain-oriented electrical steel sheets, it can be used as a reaction-promoting aid for glass coatings according to the steel sheet components and sheet thickness. In this case, for example, one or more selected from sulfates, sulfides, borates, chlorides, oxides and the like may be used in an amount of 0.005 to 0.005 parts by weight of the composite metal oxide.
It is added in a proportion of 10 parts by weight. If the amount is less than 0.005%, the effect of promoting the reaction is weak, which is not desirable. On the other hand, 10
If the amount exceeds part by weight, pinhole-like, scale-like, and gas-mark-like defects peculiar to the peroxidation reaction are generated, which is not preferable.

In the solid solution type composite metal oxide of the present invention, the role of the composite metal oxide itself is better than the role of the additive in the conventional MgO, so that the role is considerably reduced. However, if the appropriate additives and amounts are selected, a stable auxiliary effect of improving the reactivity can be obtained in accordance with the high reactivity of the composite metal oxide itself, and the atmosphere condition in the finish annealing is more stable from dry to wet. The improved reactivity is obtained.

[0027]

【Example】

Example 1 C: 0.077% by weight, Si: 3.2% by weight
3%, Mn; 0.075%, S; 0.025%, Cu;
0.008%, Sn; 0.08%, Al; 0.028
%, N: 0.0079%, the balance being unavoidable impurities and Fe
The slab of high magnetic flux density oriented magnetic steel sheet made of hot rolled, annealed, pickled, and cold rolled to a final sheet thickness of 0.225 mm by a known method. This steel sheet is N ₂ 25% + H ₂ 75
%, Decarburization annealing in a humid atmosphere gas with a dew point of 66 ° C.

Next, an annealing separator mainly composed of a composite metal oxide having a CAA value adjusted to 85 seconds and composed mainly of a composite metal oxide having a composition shown in Table 1 was dried in an amount of 12 g / kg.
m ^2, and after the final drying annealing at 1200 ° C. × 20 hours. After that, 2
100 ml of 0% colloidal silica-50% Al50 phosphate
A coating agent consisting of 6 g of ml-CrO ₃ was applied so that the weight after drying and baking was 5 g / m ² , and heat flattening and baking were performed at a furnace temperature of 850 ° C. Table 2 shows the results of the film properties and magnetic properties at this time. FIG. 1 shows the process of forming a film during finish annealing in the examples (A), (B), and (C) at this time. In the present invention (A), the formation of a glass coating is promoted.

FIG. 1 shows (A) the case of using Example 2 of the present invention 2 as the composite metal oxide of the present invention and (B) Example 2 of Example 2 of the present invention 2 in which all of Fe ³⁺ is Ca ^2+. (0.25) and T
Finishing glass film forming reaction when replaced by i ³⁺ (0.05) (Comparative Example) and (C) when conventional MgO is used (Comparative Example 1) as an annealing separator It is the result of analyzing in the annealing process. In this experiment, the grain-oriented electrical steel sheet sample applied was the same material as in Example 2, and the activity of the Mg substance as the annealing separator was CA.
The A value (measured at 30 ° C.) was adjusted to 45 seconds.

[0030]

[Table 1]

[0031]

[Table 2]

As a result, in each of the cases where the composite metal oxide of the present invention was used as an annealing separator, the glass coating was formed uniformly over the entire steel plate, and the tensile strength and adhesion of the glass coating were good. Regarding the magnetic characteristics, all of the magnetic recording media of the present invention exhibited extremely good magnetic flux density and iron loss characteristics. On the other hand, when the conventional MgO of the comparative example was applied, the film properties and the magnetic properties were considerably inferior to those of the present invention.

Example 2 C: 0.055% by weight;
Si: 3.29%, Mn: 1.00%, S: 0.007
8%, Al: 0.033%, N: 0.0080%, S
n: 0.03%, and the remainder consisting of unavoidable impurities and Fe was slab-heated at a low temperature of 1250 ° C., annealed by hot rolling, and pickled and cold rolled to a thickness of 0.225 mm. Next, decarburizing annealing was performed in an atmosphere gas of 25% N ₂ + 75% H ₂ and a dew point of 65 ° C. to form a decarburized and SiO ₂ film on the surface, and then 750 ° C. in a dry atmosphere zone provided on the same line.
A sample was prepared by performing a nitriding treatment in an atmosphere of N ₂ 25% + H ₂ 75% + NH ₃ for × 30 seconds so that the total N content of the steel sheet was 200 ppm.

CAA having the composition shown in Table 3 was applied to this steel sheet.
An annealing separator having a composite metal oxide composition whose main component was adjusted to 35 seconds was applied so as to have a concentration of 12 g / m ² , dried, and then subjected to finish annealing and insulating film treatment in the same manner as in Example 2. . Table 4 shows the results of the glass coating properties and the magnetic properties.

[0035]

[Table 3]

[0036]

[Table 4]

As a result, according to the present invention, the glass film was formed very uniformly, a product having a very high glass film tension was obtained, and the adhesion was stable. In addition, the magnetic properties were extremely good results which could not be obtained with the conventional annealing separator. On the other hand, in the case of the comparative agent, the composite metal substance in Comparative Example 1 in which the amount of the composite metal material was larger than that of the present invention area exhibited film defects such as shimofuri and gas marks as seen in the case of excessive oxidation. In Comparative Example 2, the number of defective portions of the glass coating was large, uneven and thin, and the coating tension was low. Also, the magnetic properties were considerably inferior to those of the agent of the present invention.

[0038]

The present invention relates to a novel annealing separator, Mg
A low melting point and a reaction promoting effect are obtained by a particulate composite metal oxide in which a part of Mg of O is replaced with a certain amount of divalent and / or trivalent Fe and another divalent or trivalent metal to form a solid solution. Forming a uniform, high-tensile, excellent glass coating, and by using the excellent sealing effect of the steel sheet surface during the coating formation process and the inhibitor removal process, prevent the alteration and weakening of the inhibitor and achieve good secondary recrystallization. And extremely excellent magnetic properties can be obtained.

[Brief description of the drawings]

FIG. 1 shows the temperature of the final annealing temperature rise process and the M in the surface oxide.
It is a chart with gO.

Continuing from the front page (72) Inventor Takeshi Hamaya 1-1, Tobata-cho, Tobata-ku, Kitakyushu Nippon Steel Corporation Inside Yawata Works (72) Inventor Hiroshi Sato 1-1-1, Tobata-cho, Tobata-ku, Kitakyushu New Japan (56) References JP-A-7-180064 (JP, A) JP-A-7-310188 (JP, A) JP-A-7-316831 (JP, A) (58) Survey Fields (Int. Cl. ⁷ , DB name) C23C 22/00-22/86 C21D 1/70 C21D 9/46 501

Claims (5)

(57) [Claims] 1. A ^{_{[Mg 1-x X a x1 X}} b x2 ] for very excellent grain-oriented electrical steel sheet reactivity, which is a solid solution-type composite oxide represented by the general formula of O · Ay Annealing separator. X ^a ; Fe ²⁺ and / or Fe ³⁺ X ^b ; M ²⁺ and / or M ³⁺ M ²⁺ ; Be, Ca, Ba, Sr, Sn, Mn, Co, N
i, a divalent metal such as Cu and Zn; M ³⁺ ; a trivalent metal such as Al, Cr, Co, B, Ti, and Sb A; F, Cl, Br, CO ₃ , SiO ₃ , PO ₃ , and C
One or more of rO ₃ 0.01 ≦ x1 + x2 ≦ 0.40 (provided that 0.01 ≦ x1 ≦
0.20) 0.001 ≦ y ≦ 2.0 (ratio to 100 parts by weight of composite metal oxide) 2. Specific surface area: 15 to ²⁰⁰ m ² / g, 30 ° C.
The annealing separator according to claim 1, which has a CAA value of 30 to 100 seconds as measured in step (a). 3. A material for a grain-oriented electrical steel sheet after cold rolling to a final sheet thickness is decarburized and annealed, an oxide film mainly composed of SiO ₂ is formed on the surface, and an annealing separator mainly composed of MgO is used. Coating, finish annealing, and processing and baking the insulating coating agent.
^{_{1-x X a x1 X b}} x2 ], characterized in that the O · formula solute composite oxide represented by the Ay is coated on the steel sheet, the use of reactive extremely excellent annealing separator. X ^a ; Fe ²⁺ and / or Fe ³⁺ X ^b ; M ²⁺ and / or M ³⁺ M ²⁺ ; Be, Ca, Ba, Sr, Sn, Mn, Co, N
i, a divalent metal such as Cu and Zn; M ³⁺ ; a trivalent metal such as Al, Cr, Co, B, Ti, and Sb A; F, Cl, Br, CO ₃ , SiO ₃ , PO ₃ , and C
One or more of rO ₃ 0.01 ≦ x1 + x2 ≦ 0.40 (provided that 0.01 ≦ x1 ≦
0.20) 0.001 ≦ y ≦ 2.0 (ratio to 100 parts by weight of composite metal oxide) 4. The specific surface area of the annealing separator is 15 to 200 m.
4. The method according to claim 3, wherein the CAA value measured at ² / g and 30 DEG C. is 30 to 100 seconds. 5. One or two or more selected from sulfates, sulfides, borates, chlorides and oxides as a reaction-promoting aid for forming a glass film, based on 100 parts by weight of the solid solution composite oxide. 6. The method of claim 3, wherein the addition of 0.005 to 10 parts by weight is carried out.