JPH1053818A - Production of separation agent at annealing, excellent in film forming capacity, and grain oriented silicon steel sheet using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a separation agent at annealing, excellent in application workability as well as in glass film forming capacity, and a grain oriented silicon steel sheet using this separation agent at annealing. SOLUTION: This separation agent at annealing excellent in film forming capacity is composed of oxides having a mole ratio of one or >=2 elements selected from among Al, Ca, Ti, V, Cr, Mn, Fe, Sr, Co, Zr, and Sb of 0.05-10 to Mg of 100. Further, the value of (the total number of the molar numbers of the elements other than Al)/(the molar number of Al) is regulated to 0.5-10. Moreover, BET specific surface area and hydration water content are regulated to (10 to 100)m<2> /g and 0.5-6.0%, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annealing separator having excellent glass film forming ability, a uniform and extremely excellent glass coating, and excellent coating workability at the time of producing a grain-oriented electrical steel sheet. The present invention relates to a method for manufacturing a conductive electrical steel sheet.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets usually contain less than 4% of Si.
Hot rolled material containing and contains annealing and one or two annealing
The final thickness is obtained by cold rolling more than once. Then N ₂
+ H ₂ or H ₂ or other atmosphere gas to control PH ₂ O / PH ₂ for decarburization annealing, primary recrystallization, decarburization and SiO 2
An oxide film mainly composed of ₂ is formed.

[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. Further, in the case of a high magnetic flux density oriented magnetic steel sheet, especially in a thin material having a thickness of 0.27 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.

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)
It is thought that the plane crystal grows preferentially and grows preferentially to erode other crystals whose growth is suppressed by AlN, MnS, etc. which are finely dispersed as an inhibitor in the steel. . 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.

[0005] The change in the inhibitor during the final annealing is as follows:
It is known that it is affected by an oxide film formed by decarburizing annealing, an annealing separator, a thermal cycle of final finishing annealing, and atmospheric conditions. Among these, M of the annealing separator
The properties and additives of gO have a great influence on the glass film formation start time, formation rate, film quality, quantity, etc., and therefore have a great influence on the inhibitor.

The annealing separator MgO reacts with the SiO ₂ -based oxide film formed by the decarburizing annealing to form a forsterite-based coating usually called a glass coating (2).
MgO + SiO ₂ → Mg ₂ SiO ₄ ). When a conventional MgO powder is used in the formation of the glass film, it is difficult to control the reactivity in the formation of the glass film.
In addition to the particle size, purity, and activity, the properties of gO are greatly affected by dispersibility in water, the amount of hydration, the amount of coating, the uniformity of the coating film, the adhesion to the steel sheet surface, and the like during application to steel sheets. . Further, the type and amount of the additive added as a reaction accelerator for the formation of the glass film 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.

Generally, MgO used as an annealing separator
Adjusts raw materials such as magnesium hydroxide, magnesium carbonate, basic magnesium carbonate and the like into fine-particle crystals having an average particle size of several hundreds to several thousand Angstroms;
M is fired at a high temperature of about 200 ° C and has a M of about 0.2 to 5 µm.
It is used by obtaining fine crystal particles of gO. At this time, Mg
O and additives are applied to the steel plate surface by agglomeration of particles 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 suspension in water. At this stage, the particles become coarse particles of several microns to several tens microns, causing a decrease in reactivity. In particular, in the case of conventional MgO, in order to obtain low hydrated MgO, production at high temperature sintering is indispensable, and in such a case, reactions such as sintering and agglomeration of MgO are further strengthened. For this reason, on the steel sheet surface after coating and drying, the contact area of the MgO particles is reduced, the coating film density is reduced, the adhesion to the steel sheet surface is reduced, and the uniformity of the coating film is reduced.

Further, when an additive is added to MgO as a reaction accelerator for a glass film, the additive itself also undergoes sintering during production and agglomeration in a slurry, resulting in a coating film with coarse particles. Present inside or on steel oxide film. Especially,
This phenomenon becomes more remarkable when it is added to MgO having strong cohesiveness. As a result, the reaction promoting effect weakens,
Heterogeneous reaction occurs, and it is difficult to obtain a uniform and good glass coating, thereby deteriorating magnetic properties. Therefore, development of an annealing separator having good dispersibility and good reactivity with fine particles is an important issue. On the other hand, when trying to obtain highly active and reactive MgO, the hydration moisture tends to increase, and at the same time, the viscosity of the slurry increases, and there is a problem that uniform application properties cannot be obtained in the coating operation in a high-speed line. is there.

As a production technique of an annealing separator MgO having excellent reactivity, Japanese Patent Application Laid-Open No. 02-267278 discloses a technique in which baked MgO is passed through a steam-containing atmosphere at 100 ° C. or higher to form an OH chemically adsorbed layer on the MgO surface. Mg in ₂ O conversion
There has been proposed a technique in which an annealing separator containing 0.8 to 2.5% of MgO based on the amount of O is applied to a steel plate after decarburizing annealing 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 7-310188 discloses that [Mg _-X M ³⁺ _X ] O, [Mg _-X M ²⁺
_X] O, [Mgl _-X M ²⁺ _X1 M ³⁺ _X2] composite metal oxide represented by the general formula of O has been proposed (M ^2+; Be, C
a, Ba, Sr, Sn, Mn, Fe, Co, Ni, C
u, Zn, M ³⁺ ; Al, Fe, Cr, Co, B, Ti,
Sb 0.01 ≦ x ≦ 0.40, x = x1 + x2). In the present invention, a part of Mg is substituted and solid-dissolved by the above-mentioned divalent or trivalent, and the melting point is lowered by the composite metal oxide, whereby a uniform and high-tensile glass film can be obtained. In this technique, as a solution to coagulation of MgO particles at the time of applying an annealing separating agent, the MgO surface after annealing is modified by performing a special surface treatment at a high temperature, or MgO is combined (solid solution). Or lowering the melting point. Further, it is to obtain MgO of fine particles to improve the glass film forming reaction, and a considerable improvement effect is obtained.

However, the sintering caused by the MgO production conditions, the stability of the OH chemically adsorbed layer, the agglomeration due to the aging change from the MgO production to the use, the hydration moisture, and the viscosity control in the coating process cause problems. The problems of uniform coating and the like were not completely solved, and there were problems that could not be avoided such as troubles in the coating and magnetic properties depending on the quality of the oxide film formed in the decarburization annealing. For this reason, there has been a demand for the development of MgO which has a lower hydration, a higher reactivity, and an excellent coating workability in a coating process on site.

In the present invention, as a solution to the above-mentioned problems in the prior art, it has been made to solve the problems of the applicability of the annealing separator and the reaction of forming a glass film.

[0013]

SUMMARY OF THE INVENTION According to the present invention, when applying an annealing separator in the production of grain-oriented electrical steel sheets, there is a limit on the improvement of reactivity and the lowering of the melting point in the conventional glass film formation of MgO. Problems and hydration properties of the annealing separator slurry,
The problem of uneven coating in high-speed lines caused by the problem of viscosity is solved by applying a new annealing separator. Accordingly, an object of the present invention is to provide a method for manufacturing a grain-oriented electrical steel sheet that can form a uniform glass film and obtain good magnetic properties.

[0014]

Means for Solving the Problems In the glass coating forming process from the decarburizing annealing to the final finishing annealing of the grain-oriented electrical steel sheet, the present inventors manufactured a product having a uniform glass coating and excellent magnetic properties. The method was discussed. In this study, the research was conducted focusing on the improvement of the reactivity of MgO used as an annealing separator and the properties of the slurry during the coating operation.

As an annealing separator, MgO and an additive such as a Ti compound are usually used as a reaction accelerator. In such prior art, the properties of MgO affect glass film formation, mainly the reactivity and stability of the film,
Because it has a great effect on not only the coating but also the magnetic properties,
This is because the auxiliary effect of the additive is rather important.

The present inventors have conducted extensive research and experiments on a composite oxide MgO as a novel highly reactive annealing separator. As a result, Al, Ca, Ti,
The hydration of the annealing separator can be achieved by containing a certain amount of one or more of V, Cr, Mn, Fe, Sr, Co, Zr, and Sb and keeping the molar ratio with Al within a certain range. A highly reactive oxide of fine particles having improved moisture and viscosity can be obtained.
As a result, the application of the high-speed sheet passing on-site is easy, the glass film is stabilized under a wide range of other process conditions, and the technology for improving the magnetism has been developed.

The present invention relates to a method for manufacturing a grain-oriented electrical steel sheet.
When applying an annealing separator on the steel sheet surface after decarburizing annealing,
Novel annealing separator applied and directional electromagnetics using it
It relates to a steel plate. The summary is as follows:
You. (1) Al, Ca, T with respect to Mg;
i, V, Cr, Mn, Fe, Sr, Co, Zr, Sb
One or more selected from among 0.05 to 1 in total
0, and (moles of elements other than Al
(Total number of ratio) / (mol number of Al) ratio is 0.5 to 1
0 and the BET specific surface area is 10 to 100 m ^Two/ G, water
Baking with excellent film-forming ability with a total water content of 0.5 to 6.0%
Blunt separating agent. (2) Al, Ca, Ti, V, Cr, M in the annealing separator
1 selected from n, Fe, Sr, Co, Zr, and Sb
More than 20% of the total of the seed or two or more kinds in the MgO crystal
Those who are superior in the film forming ability of the above (1), which are substituted solid solution
Annealing separator for grain-oriented electrical steel sheets. (3) Grain-oriented electrical steel sheet coil cold-rolled to final thickness
After decarburizing annealing, applying an annealing separator and drying, finish annealing,
In the process consisting of applying and baking an insulating film agent
Claim (1) or on the steel sheet surface after decarburization annealing
When performing the final annealing after applying and drying the annealing separator of (2)
And the atmosphere gas at the time of temperature rise is changed to N_Two10-90%, balance H
_TwoAnd PH_TwoO / PH_TwoTo 0.01 to 0.4
A method for producing grain-oriented electrical steel sheets with excellent dull glass coating.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, Mg100 is used as a molar ratio.
Al, Ca, Ti, V, Cr, Mn, F
e, Sr, Co, Zr, and Sb are oxides of one or more selected from 0.05 to 10 and the total mole number of these elements other than Al / the mole number of Al is 0.1. BET specific surface area of 10 to 100 m ² / g and hydrated water of 0.5 to 6.
It is characterized by being 0%, whereby excellent coating workability and a glass film forming effect in a high-speed line can be obtained.

In the Mg compound of the present invention, it is essential to contain a certain amount of Al. Al is added at the stage of hydroxide in a normal MgO production process. This Al
Has the effect of suppressing the growth of MgO-based hydroxide crystals and at the same time very effectively suppressing the sintering of the oxide obtained by firing this hydroxide. As a result,
Very fine oxides are obtained. Al is Mg1 in a molar ratio.
It is added at a ratio of 0.05 to 10 with respect to 00. 0.
Addition of not more than 05 significantly reduces the effect of suppressing the crystal growth and sintering of the hydroxide. On the other hand, when it is 10 or more, MgO-based oxide after firing is too active to inevitably cause high hydration, and the viscosity of the slurry becomes too high, making it difficult to perform a uniform coating operation with high-speed sheet passing. . In addition, these may cause non-uniformity of the glass film and film defects,
It is not preferable because the magnetic properties are deteriorated. In the present invention, it is important to add Ca, Ti, V, Cr, Mn, Fe, Sr, Co,
It is the ratio of the total amount of one or more Zr to the amount of Al. These other additional elements have a function of lowering the melting point of the oxide mainly composed of Mg while inactivating the oxide. When this ratio is 0.5 to 10 in terms of molar ratio, a low hydration oxide can be obtained while keeping the effect of making the oxide fine. As a result, an oxide having a low hydration and an extremely high reactivity as compared with ordinary MgO is obtained. Further, since the viscosity of the slurry can be freely controlled by this ratio, an oxide suitable for the conditions of the production line can be obtained. If the ratio is less than 0.5,
The dehydration effect by this inactivation cannot be obtained. Also,
It is difficult to obtain the effect of controlling the viscosity of the slurry. On the other hand, if the ratio is 10 or more, the action is too strong, the effect of atomization is reduced, and the reactivity of forming a glass film is lowered.

Next, a certain amount of Al is contained, and Ca, Ti,
The oxide of the present invention containing a constant ratio of other elements such as V, Cr, Mn, Fe, Sr, Co, Zr, and Sb in a molar ratio is characterized by the specific surface area of the oxide controlled by the ratio. There is. An oxide produced by a process like the present invention is characterized in that an extremely fine oxide can be obtained, particularly in the case of an Al-containing Mg compound, for the above-described reason. In the case of ordinary MgO, although it depends on the manufacturing process conditions, there is no miniaturization effect of Al of the present invention, so
Only a specific surface area of about 20 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. Further, it is characterized in that high reactivity is obtained at a low melting point even with a specific surface area similar to that of conventional MgO. This allows
The reactivity in forming a glass coating is improved, and a grain-oriented electrical steel sheet having extremely excellent coating and magnetic properties can be obtained. If the specific surface area is in the range of 10 to 100 m ² / g, the effects of low hydration, high reactivity and slurry viscosity optimization aimed at by the present invention can be obtained.

According to the present invention, the BET specific surface area is 10 m.^Two
/ G is less than glass even with the component oxide of the present invention.
It is not preferable because the effect of improving the formation becomes small. On the other hand, 10
0m ^Two/ G or more, the viscosity becomes too high, and
Becomes difficult to apply. In addition, it is difficult to control hydration moisture.
Depending on the conditions of decarburizing annealing and finish annealing.
Film cannot be obtained.

Next, in the case of the oxide of the present invention, the water of hydration is 0.5 to 6.0%. In the present invention, the effect of improving the film-forming reaction by atomizing oxide particles and improving reactivity by Al and other metal elements added at a fixed ratio to Mg is obtained. However, if it is less than 0.5%, the atmosphere between the steel sheets in the step of raising the temperature of the finish annealing becomes too dry, and the quality of the decarboxylation film is changed, so that the thickness of the glass film becomes thin or the adhesion decreases. A drop in tension occurs. on the other hand,
When the content exceeds 6.0%, even with the highly reactive annealing separator of the present invention, as a peroxide-like film defect, shimofuri, gas mark, scale, and the like are easily generated particularly in a large coil, so that it is limited. .

In the present invention, ordinary MgO
One of the features is that the glass film formation is excellent from the low hydration region to the high hydration region as compared with the case where is used. Usually MgO
The glass film formation reaction by the method mainly utilizes the effect of decomposing Mg (OH) ₂ generated by hydration of MgO during the finish annealing temperature raising process and making the steel plates wet. On the other hand, in the case of the present invention, as described above, the effect of moisture is not so required due to the effect of forming fine particles and improving the reactivity by the additive element such as Al. For this reason, the reactivity is good in the low hydration region and the glass film is formed at a low temperature, so that the additional oxidation at a high temperature can be suppressed, so that it is hardly affected by moisture.

Next, the additional elements Al, Ca, Ti, V, Cr, Mn, and F used together with Mg in the present invention.
Preferably, 20% or more of the total of one or more selected from e, Sr, Co, Zr, and Sb is in a solid solution state in the MgO crystal. After these additive elements have a hydroxide structure, they are converted into oxides by firing. For this reason, a solid solution type complex oxide structure is exhibited depending on the hydroxide generation conditions and firing conditions. If the amount of the solid solution is less than 20%, the effect of improving the formation of the glass film is weak, and it becomes unstable depending on the conditions of decarburizing annealing and finish annealing.

Next, the oxide of the present invention is used as an annealing separator.
When the annealing gas is N_Two1
0-90%, balance H_TwoAnd PH_TwoO / PH_TwoIs 0.0
1 to 0.4. In the annealing separator of the present invention,
Good glass film shape even in a relatively dry atmosphere due to its responsiveness
Is done. Atmospheric gas N_TwoThe ratio is mainly the cost of secondary recrystallization.
Limited in qualitative terms. N_TwoIf it is less than 10%,
Reduction of the decarboxylation film occurs, reducing the glass film formation reaction.
While using AlN as an inhibitor
Inhibition is accelerated, and secondary recrystallization becomes unstable
Sprinkle. On the other hand, N _TwoIf it exceeds 90%, nitriding of the steel sheet occurs.
This affects the amount and form of AlN. Again, in this case,
It is not preferable because the magnetic properties are deteriorated. Atmosphere gas
PH_TwoO / PH_TwoIs less than 0.01,
A reduction reaction of the decarboxylation film occurs in the
Decrease. In this case, too, the inhibitor is prematurely magnetized
Causes instability. On the other hand, if it exceeds 0.4,
Non-uniform additional oxidation occurs in the high temperature range during the temperature, and the annealing of the present invention is performed.
Even with a separating agent, a uniform glass film cannot be obtained.
In particular, defects are likely to occur in the outer peripheral portion and the edge portion of the coil. This
In the case of overheating, deoxidation occurs due to excessive oxidation
Is seen to decrease. In the range of 0.01 to 0.4
Good glass film and good magnetic properties
You.

FIG. 1 shows (A) the annealing separator of the present invention.
Example 2-The case where the present invention 4 was used and (B) Example 2-
The results of analyzing the glass film forming reaction in the case of adding only Al of Comparative Example 1 and (C) the case of using the conventional MgO of Comparative Example 2 of Example 1 as an annealing separator in the finish annealing process are shown. In this experiment, the grain-oriented electrical steel sheet sample applied was the same material as in Example 2.

As shown in FIG. 1, it was confirmed that the glass according to the present invention formed a glass film from a lower temperature in the course of the finish annealing heating, and the final formation amount was larger than that of the comparative example. However, it was confirmed that in the comparative example to which only Al was added, the film formation amount was small due to slightly inferior reactivity, and when the conventional MgO was used, the film formation amount was extremely small.

[0028]

【Example】

<Example 1>C; 0.054, Si; 3.0% by weight.
0, Mn; 0.060, S; 0.024, Al; 0.0
07, the remainder of the grain-oriented electrical steel sheet material consisting of unavoidable impurities and Fe was cold rolled twice with hot rolling and annealing by a known method to a final sheet thickness of 0.34 mm. After this, furnace temperature 85
Decarburizing annealing in an atmosphere gas of 0 ° C., 25% N ₂ + 75% H ₂ and a dew point of 66 ° C. to form an oxide layer mainly composed of SiO _{2 on the} surface after decarburizing. 1500 rp in a tank with a propeller-like stirring device at a liquid temperature of 5 ° C
After stirring for mx 120 min., the mixture was applied, dried, wound around a 20T coil, and subjected to final annealing at 1200 ° C for 20 hours. Thereafter, an insulating coating agent composed of 20% colloidal silica: 100 ml, 50% Al phosphate: 50 ml, and CrO ₃ : 4 g was applied so that the weight after drying was 2.5 g / m ^2.
Heat flattening and baking were performed at 50 ° C. Table 2 shows the state of formation of the glass film after the finish annealing in this test and the film properties after the baking treatment with the insulating film.

[0029]

[Table 1]

[0030]

[Table 2] As a result of this experiment, in any of the devices according to the present invention, a thick and glossy glass film was formed over the entire surface of the coil, and the adhesion of the film after the insulating film treatment was good. On the other hand, ordinary MgO was used for the annealing separator of the comparative example.
In the case where the ratio of other elements to Al and the added element is small outside the present invention, the glass film is thin or gas mark-like unevenness occurs at the edge of the steel sheet, and the adhesion is considerably higher than that of the present invention. Inferior results. Also, in the magnetic properties, in the case of the annealing separator of the present invention, the magnetic properties are stable and good, especially, while the iron loss showed a very good value,
In the comparative example, both the magnetic flux density and the iron loss were inferior.

Example 2 C: 0.080, S by weight%
i; 3.30, Mn; 0.075, S; 0.025, C
u; 0.08, Sn; 0.06, Al; 0.028,
N: 0.0079 high magnetic flux density directional magnetic steel sheet material composed of unavoidable impurities and Fe with the balance being 0.0079 by hot rolling, annealing, pickling, and cold rolling by a known method to a final sheet thickness of 0.225 mm.
And The steel plate _{N 2 25% + H 2 75} %, dew point 68
Decarburization annealing was performed at 850 ° C. for 120 seconds in a humid atmosphere gas at 850 ° C. Next, an annealing separator ^{(* 1)} containing an oxide as a main component having the composition shown in Table 3 was stirred at a liquid temperature of 10 ° C. using the same stirring apparatus as in the example at 1,000 rpm × 60 minutes. Next, it was applied so that the weight after drying was 12 g / m ^2, and after the drying, final finishing annealing at 1200 ° C. × 20 hours was performed. Thereafter, a coating agent having the same composition as in Example 1 was applied as an insulating coating agent 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 4 shows the results of the film properties and magnetic properties at this time.

As a result of this test, in each of the cases where the oxide of the present invention was used as an annealing separator, the glass coating was formed uniformly over the entire length and the entire surface of the coil, and the tension and adhesion of the glass coating were good. Was. 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, in the comparative example, the addition of Al alone or the one in which the addition of other elements other than Al is small indicates hydration
Slurry viscosity is high, coating cannot be performed uniformly, film magnetic,
Both magnetic properties were poor. In addition, when Al was not added, sintering occurred during firing, resulting in the formation of a glass film and the magnetic properties were slightly inferior.

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

As described in detail above, the present invention provides a novel annealing separator as a new annealing separator in a molar ratio of M
g100 with respect to 0.05 to 10 Al and Ca, Ti,
By using an oxide prepared by adding V, Cr, Fe, Mn, Co, Zr, Sb, etc. to Al at a ratio of 0.5 to 10, an effect of lowering the melting point and an effect of improving the reactivity can be obtained.
Further, the viscosity is easily controlled at the time of adjusting the slurry in the coating step, and uniform coating can be realized even in a high-speed line. As a result, the glass film is formed uniformly over the entire surface of the coil, thereby preventing deterioration and weakening of the inhibitor, thereby obtaining good magnetic properties.

[Brief description of the drawings]

FIG. 1 shows an example of an annealing separator of the present invention (A) of Example 2-
Glass coating in the case of using the present invention 4, (B) in the case of adding only Al of Example 2-Comparative Example 1, and (C) in the case of using the conventional MgO of Comparative Example 2 of Example 1 as an annealing separator. It is a figure which shows the result of having analyzed the formation reaction in the finish annealing process.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norihiro Yamamoto 1-1 Niwahata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Yawata Works (72) Inventor Osamu Tanaka Larger section of Tobata-ku, Kitakyushu-shi, Fukuoka Inside Nippon Steel Plant Design Co., Ltd. at 46 Nakahara

Claims (3)

[Claims] 1. A molar ratio of Mg; 100 to Al, C
a, Ti, V, Cr, Mn, Fe, Sr, Co, Zr,
One or more selected from Sb is used in a total of 0.0
An oxide composed of 5 to 10 and having a ratio of (total number of mole ratios of elements other than Al) / (mol number of Al) of 0.5
And a BET specific surface area of 10 to 100 m ² /
g, an annealing separator for grain-oriented electrical steel sheets having excellent film-forming ability, having a hydrated water content of 0.5 to 6.0%. 2. The method according to claim 1, wherein Al, Ca, Ti, V,
2. The MgO crystal according to claim 1, wherein at least 20% of a total of one or more selected from Cr, Mn, Fe, Sr, Co, Zr, and Sb is substituted and solid-solved in the MgO crystal.
An annealing separator for grain-oriented electrical steel sheets having excellent film-forming ability as described. 3. A process comprising the steps of decarburizing and annealing a grain-oriented electrical steel sheet coil cold-rolled to a final thickness, applying and drying an annealing separating agent, finish annealing, and applying and baking an insulating film agent. 3. The steel sheet surface after carbon annealing
When performing the finish annealing after applying and drying the described annealing separator, the atmosphere gas at the time of temperature rise is N ₂ 10 to 90%, and the remainder is H.
_2, and the manufacturing method of the grain-oriented electrical steel sheet having excellent glass coating film, which comprises annealing the PH ₂ O / PH ₂ as 0.01 to 0.4.