JP2002004061A - Separating agent for annealing grain oriented electrical steel sheet and method of producing the grain oriented electrical steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grain oriented electrical steel sheet having uniform and excellent film properties and excellent magnetic properties, which is obtained by improving a separating agent for annealing to form, especially, a forsterite-based insulating film when the grain oriented electrical steel sheet is produced. SOLUTION: The separating agent for annealing is used for producing the grain oriented electrical steel sheet which is produced by making the separating agent for annealing containing MgO as a main component into slurry, then coating the slurry on a steel plate, drying and subjecting the coated steel sheet to final finishing annealing. The separating agent for annealing is characterized by that the 90 % diameter of the separating agent for annealing coated on the steel sheet and dried is shorter than the 90 % diameter of the separating agent for annealing before being made into the slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of grain-oriented electrical steel sheets, in particular, by improving an annealing separator for forming a forsterite-based insulating film to provide uniform and excellent film properties and excellent An object is to obtain a grain-oriented electrical steel sheet having magnetic properties.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets have a Si content of 2.5-4.
A material slab containing 0% is hot-rolled, and the final sheet thickness is obtained by annealing and one or two or more cold rollings sandwiching intermediate annealing. Then, in a continuous annealing furnace, H ₂ or N ₂ + H
Decarburization annealing is performed in _two atmospheres, and decarburization treatment, primary recrystallization treatment, and oxide layer formation treatment containing SiO ₂ as a main component are performed. Thereafter, an annealing separator containing MgO as a main component is applied to the steel sheet and dried. The steel sheet is wound into a coil and subjected to final finish annealing, and then subjected to an insulating coating agent treatment and a heat flattening treatment to become a final product.

A grain-oriented electrical steel sheet has excellent magnetic properties due to the presence of many Goss-oriented crystal grains having a <001> orientation in the rolling direction. The Goss-oriented grains grow during the secondary recrystallization in the final finish annealing step. The preferential growth of Goss-oriented grains is caused by precipitates (AlN, MnS, etc.) dispersed as inhibitors in steel.
This is because the growth of crystal grains in other directions than the crystal orientation is suppressed to the Goss crystal growth start temperature range. Therefore, in order to manufacture an excellent grain-oriented electrical steel sheet, the dispersion state of the inhibitor (AlN, MnS, etc.) in the steel is appropriately controlled,
It is important to grow Goss-oriented crystal grains having the <001> orientation as accurate as possible. The dispersion state of the inhibitor in the steel varies depending on various factors, and particularly, the formation state of the forsterite film formed at the time of final finish annealing has a great influence.

[0004] Forsterite coating consists of SiO ₂ in an oxide layer formed during decarburizing annealing and MgO in an annealing separator.
However, during the final annealing, SiO ₂ + 2MgO → Mg ₂
It is formed by reacting like SiO ₄ (forsterite). Since this forsterite film is formed on the surface of the steel sheet, it plays an important role in controlling the exchange between the inhibitor in the steel and the atmosphere gas in the final annealing.

[0005] The forsterite film is formed in a temperature range of about 900 ° C during the temperature rise process during the finish annealing. However, when the progress is delayed or the formed film exhibits an uneven or porous structure. In this case, since O and N excessively penetrate into the steel from the finish annealing atmosphere, the inhibitor in the steel is decomposed, coarsened or excessively dispersed, and a proper inhibitor dispersion state cannot be obtained. Also, if the forsterite film formation reaction proceeds too early from the low temperature range, the inhibitor constituent elements are excessively absorbed from the steel into the forsterite film, so that the inhibitor in the steel becomes insufficient and the proper Inhibitor dispersion cannot be obtained.

The progress and form of the forsterite film forming reaction include the amount and form of SiO _{2 in} the oxide layer on the surface of the steel sheet, the properties of MgO in the annealing separator (purity, reactivity, progress of hydration, particle size). , Coating amount, etc.) and the gas composition of the final annealing atmosphere. In particular, M in the annealing separator
The reactivity of gO is very important for forsterite film formation. When the reactivity of MgO is deteriorated, the reaction between SiO ₂ in the oxide layer on the surface of the steel sheet and MgO in the annealing separator hardly progresses, and the forsterite film is hardly formed. If the good reactivity of MgO SiO ₂ and Mg
The reaction with O easily proceeds, and the forsterite film is easily formed.

The reactivity of MgO varies depending on various factors, but the influence of the particle size of MgO is particularly large. When the MgO particles are large, the surface area per unit weight decreases and the reaction area decreases, so that the reaction between SiO ₂ and MgO becomes difficult to progress, and the MgO reactivity deteriorates. In addition, even when a film-forming accelerator is added, the MgO particles are large, so that the accelerator concentration becomes non-uniform microscopically, and the MgO reactivity deteriorates locally in portions where the accelerator concentration is low, resulting in uniformity. A good forsterite film cannot be obtained. On the other hand, Mg
When the O grains are small, the surface area per unit weight increases and the reaction area increases, so that the reaction between SiO ₂ and MgO easily proceeds, the MgO reactivity is improved, and the film-forming accelerator and the like are uniformly dispersed. Therefore, a uniformly good forsterite film can be obtained.

Usually, an annealing separator mainly composed of MgO is first mixed with water to form a slurry, and then applied to a steel sheet using a grooved roll or the like. Then, after a drying process for removing moisture, the steel sheet is wound into a coil shape and subjected to final finish annealing. In order to obtain a good forsterite film, the MgO slurry must be uniformly applied to the steel sheet surface, but the particle size of the MgO has a great influence on the applicability of the MgO slurry. That is, when the MgO particles are small, the MgO particles are easily applied uniformly to the steel sheet, the adhesion to the dried steel sheet is good, and the state of forming the forsterite film is good. On the other hand, when the MgO particles are large, the uniform coating property is degraded, and peeling may occur during drying, and the state of forming the forsterite film is deteriorated. Thus, MgO
The particle size is greatly related to the reactivity of MgO and the applicability of MgO slurry, and as a result, affects the state of formation of the forsterite film, and has a great influence on the state of dispersion of the inhibitor and further on the magnetism of the grain-oriented electrical steel sheet.

[0009] Much research has been done on MgO particle size since the past. For example, Japanese Patent Application Laid-Open No. Hei 5-239664 discloses a method of performing atomization by an ultrafine pulverizer in the process from slurry adjustment to steel sheet application. By this mechanical method, the MgO grains become ultrafine,
Since the surface area of the entire O grains is increased, the reactivity of MgO is improved, and uniform coating properties on the steel sheet surface can be secured. However, Mg
Since the O particles were too small, there was a problem that particles in the MgO slurry were likely to be excessively aggregated. as a result,
There is a danger that the narrow space between the ultrafine grinders will be blocked, and in some cases, the MgO particles will be too agglomerated and consequently quite coarse, eventually resulting in the MgO particles having a large size.
There was also a problem that the O reactivity and the coatability of the MgO slurry deteriorated.

JP-A-10-88242 discloses that Mg
A method has been proposed in which the agglomeration characteristics of MgO particles when O powder is mixed with water to form a slurry are defined in a certain region in a graph showing the stirring speed on the horizontal axis and the cumulative 90% diameter on the vertical axis. .
This method obtains the conditions for forming a forsterite film having uniform and excellent film properties by controlling the “agglomeration” occurring when the MgO powder is converted into the MgO slurry within an appropriate range. However, since the operating conditions are strict, which is impossible even if they deviate from the specified ranges of the vertical axis and the horizontal axis, more accurate operation technology is required than before, and those that deviate from the specified ranges are unusable. It had to be discarded, which was disadvantageous in terms of factory operation, which caused various troubles.

[0011]

As described above, in the prior art, even if there is a method of obtaining a good forsterite film by controlling the particle size of MgO and the coagulation of MgO particles in a slurry, it is difficult to improve the manufacturing site. In addition, the operability becomes difficult, and those deviating from the specified conditions have the disadvantage that excellent coating properties cannot be obtained. Therefore, it has been desired to develop a method capable of easily controlling the particle size of MgO and obtaining a good forsterite coating without finely specifying the operation and equipment conditions.

In order to solve these problems, the present invention fully considers the property that “MgO particles agglomerate in a slurry to increase the size of MgO particles”. However, the present invention provides a method in which the MgO particles after being applied to the steel sheet and dried become small, and which does not impose a load on the on-site operation.

[0013]

SUMMARY OF THE INVENTION The present inventor has found that, even when MgO particles are agglomerated in a slurry, the MgO particles after being applied to a steel sheet and dried are reduced in size. Rather than achieving the purpose by changing or modifying the equipment, it was thought that if the MgO powder itself had the property to achieve the purpose, it could be easily handled without particularly changing the manufacturing site conditions. Therefore, as a property of MgO powder, if the MgO powder is represented by “MgO particle size before slurrying> MgO particle size after coating and drying on steel sheet”, “MgO particle size after aggregation in slurry> Slurry” M before doing
gO particle size ”, it means that“ MgO
Particle size> MgO particle size after coating and drying on steel sheet ", and a desired method of" Even if MgO particles are agglomerated in the slurry, the MgO particles after coating and drying on the steel sheet become small "can be realized.

That is, a material slab containing 2.5% to 4.0% of Si is hot-rolled, and is subjected to annealing and one or two or more cold-rolling steps of intermediate annealing to obtain a final sheet thickness. Decarburizing annealing is performed in an H ₂ or N ₂ + H ₂ atmosphere in an annealing furnace, and then an annealing separator containing MgO as a main component is slurried, applied to a steel plate, dried, wound into a coil, and finally finished. In a method for producing a grain-oriented electrical steel sheet comprising a series of steps of performing annealing, an annealing separator mainly containing MgO applied to a grain-oriented electrical steel sheet produced by this method, applied to a steel sheet, and dried. 90% of the annealed separating agent is 9% of the annealed separating agent before slurrying.
The object of the present invention can be solved by using a material having a diameter smaller than 0%.

The drying of the slurry in the above step is desirably performed after the slurry is applied to a steel sheet and held in an annealing furnace heated to a temperature of 500 to 900 ° C. for 3 to 40 seconds. the atmosphere in the drying furnace may be an oxygen-free atmosphere such as N ₂ in air.

As the MgO powder, one obtained by subjecting a substance containing Mg to a treatment for obtaining MgO by firing at 1500 ° C. or more is particularly suitable. Here, the substance containing Mg refers to MgCl ₂ , magnesium carbonate, basic magnesium carbonate, seawater, bittern, rock salt, etc.
(OH) ₂ is acceptable. 15 containing Mg
As a specific processing method of obtaining MgO by firing at 00 ° C. or higher, an “Arman reactor” method is known.
This method uses about 2 g of concentrated seawater containing MgCl ₂ as a main component.
It is obtained by firing at about 000 ° C. to obtain MgO.

The 90% diameter before the slurry is 100 μm.
m or less is preferable. Here, the 90% diameter is the diameter of the 90% MgO particle counted from the small particle diameter.
As a measuring method of the 90% diameter, a laser diffraction type particle size distribution measuring device is used. In the present invention, LA-500 manufactured by HORIBA is used, and measurement conditions are selected by using distilled water at room temperature as a dispersion and a maximum rotation speed of 1 as a stirring method.
The fourth selection of eight-step adjustment at 000 rpm, the third selection of seven-step adjustment at a maximum discharge rate of 600 ml / min as a circulation method, no ultrasonic dispersion bath was used, and the required sample amount was within the appropriate range indicated on the apparatus.

As a method of collecting the MgO powder sample for measuring the particle size, the MgO powder before the slurry was arbitrarily taken out of a paper bag or a flexible container pack containing the MgO powder. In the actual product coil, the MgO powder applied to the steel sheet and dried is 10 mm after the end of the drying from the entire width of the dried steel sheet surface.
Within minutes, the amount needed for the measurement was mechanically scraped. Here, besides using the actual product coil, the effects of the present invention can be confirmed in a laboratory as follows.

First, 100 g of MgO powder is arbitrarily taken out of a paper bag or a flexible container pack containing MgO powder. Next, 100 g of the MgO powder is charged into 750 cm ³ of water cooled to a temperature of 0 to 5 ° C., and stirred at a stirring speed of about 1000 rpm to prepare an MgO slurry. Then, M is applied to both sides of a steel plate of about 0.3 mm thickness mainly composed of iron.
After drying the gO slurry, the MgO powder weight was 5 g / m
^It is applied so as to be ² and kept for 15 seconds in a laboratory furnace in an air atmosphere heated to 500 ° C. The temperature of the steel sheet after annealing becomes about 300 ° C., and the applied MgO slurry is in a sufficiently dried state. The dried MgO powder is scraped off from the surface of the steel sheet using a spatula or the like to form a sample for particle size measurement.

A comparison is made by measuring the 90% diameter of the MgO powder after coating and drying on the steel sheet thus obtained and the MgO powder before slurry arbitrarily taken out of a paper bag or a flexible container pack. In addition, as a measuring method of the 90% diameter, a laser diffraction type particle size distribution analyzer is used, and the details are as described above. As a result of the measurement, if the 90% diameter of the MgO powder after application and drying is smaller than the 90% diameter of the MgO powder before the slurry, it can be determined that the MgO powder has the effects of the present invention.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the invention will be described below. The inventors investigated the effect of the MgO on the magnetic properties and the film properties using MgO obtained by changing the manufacturing method and the particle size in various ways. as a result,
Magnetic properties and coating properties of MgO produced by the Amann reactor method, when the 90% diameter of the annealing separator after coating and drying on a steel sheet is smaller than the 90% diameter of the annealing separator before slurrying. Is newly found to be improved. That is, since the MgO of the present invention satisfies “MgO particle size before slurrying> MgO particle size after coating and drying on steel sheet”, magnetic properties and coating properties are improved.

Here, the differences between the armor reactor system and the conventional rotary kiln system and muffle furnace system will be described. Although quicklime (CaO) is not added during the production of MgO in the Arman reactor method, quicklime is added in the rotary kiln method and the muffle furnace method. Therefore, the MgO produced by the Arman reactor method is the same as the MgO produced by the rotary kiln method and the muffle furnace method.
It is characterized in that the CaO content is lower than that of CaO. Next, the firing temperature of the armor reactor system is higher than that of the rotary kiln system or muffle furnace system. The temperature of 1500 ℃ or more in the Armant reactor system, on average about 2000
C., whereas the rotary kiln method sinters at 800-1000 ° C., and the muffle furnace method fires at 1000-1000 ° C.
Baking at a temperature of 1200 ° C. In general, the rotary kiln method is a method of baking in a heated rotating furnace, and the muffle furnace method is a method of baking in a relatively small kettle-shaped annealing furnace while appropriately stirring.

The characteristics of the MgO of the present invention are as follows. (1) The 90% diameter after coating and drying on a steel sheet is smaller than the 90% diameter before slurrying. (2) Manufactured by the Arman reactor method. (3) firing at a temperature of 1500 ° C. or higher (around about 2000 ° C.); (4) CaO content is low. The most significant feature of the MgO of the present invention is that the “90% diameter after coating and drying on a steel sheet is smaller than the 90% diameter before slurrying” as described in the above (2) to (4). It is considered that this is largely related to the phenomenon that has actually occurred, such as Mg produced by firing at about 1000 ° C. in a conventional rotary kiln system or muffle furnace system.
Unlike O, in the drying stage after coating on the steel sheet, it can be estimated that the cracks of the MgO particles are enlarged or newly generated, the division proceeds, and the overall grain size is reduced.

Next, the reasons for limitation of the present invention will be described. First, MgO applied to the present invention is characterized in that the 90% diameter of the annealing separator after coating and drying on a steel sheet is smaller than the 90% diameter of the annealing separator before forming into a slurry. If the 90% diameter after coating and drying on a steel sheet is larger than that before slurry, it indicates that excessive agglomeration reaction has occurred, that is, MgO particles are agglomerated and considerably coarsened, so that MgO reactivity and MgO This is not good because the slurry coatability deteriorates.

The 90% diameter of the annealing separator before slurry is 10%.
It is preferably 0 μm or less. 90% before slurry
If the diameter exceeds 100 μm, the coatability of the MgO slurry deteriorates. The lower limit of the 90% diameter is not particularly limited as long as the 90% diameter after coating and drying on the steel sheet is smaller than that before the slurry, and thus is not limited.

As a production method, a method in which a Mg-containing substance is subjected to a treatment of obtaining MgO by firing at 1500 ° C. or higher is particularly suitable, and a method of firing at about 2000 ° C. is preferable. As this method, an Armor reactor method is known, but in a conventional rotary kiln method or a muffle furnace method, a material containing Mg is heated to 1500 ° C. or more (preferably about 2000 ° C.) by the same concept.
(Approx. ° C.), the MgO of the present invention can be obtained. At a sintering temperature of less than 1500 ° C., it becomes difficult for the MgO particles agglomerated in the slurry to be divided and refined in the drying stage, and the effect of the present invention cannot be obtained. We believe that the effect of the present invention is more likely to be obtained when firing at a high temperature.
Approximately about 2000 ° C. is optimal in view of the durability of the gO powder production equipment.

As for chemical components, it is preferable that CaO is 0.3% or less. The MgO produced by the Ahrmann reactor method is characterized in that the content of CaO is smaller than the MgO produced by the rotary kiln method and the muffle furnace method. Is estimated to have contributed. If CaO is present in excess, the formation of the forsterite film tends to deteriorate, which is not good. From the above, the upper limit of the CaO content is set to 0.3%, which is equal to the upper limit of the range of components normally produced by the Arman reactor method.

As a method for drying the MgO slurry, it is preferable to apply the slurry to a steel plate and then hold it in an annealing furnace heated to a temperature of 500 to 900 ° C. for 3 to 40 seconds. If the drying method is out of this range, the effects of the present invention cannot be obtained to the maximum, and furthermore, the water cannot be sufficiently removed or the steel sheet is overoxidized, so that the state of formation of the forsterite film deteriorates. The atmosphere in the drying furnace may be air or an oxygen-free atmosphere such as N ₂ , but if it is in the air, the cost is lower in terms of cost.

The same effects of the present invention can be obtained by mixing MgO of the present invention with other powders of MgO other than the present invention as long as the effects of the present invention can be obtained. Other powders include TiO ₂ powder, Sb compound, B compound,
Cl compounds and the like.

[0030]

[Example 1] C: 0.05%, Si: 3%,
Mn: 0.06%, S: 0.03%, N: 0.005
%, Cu: 0.2%, the balance is decarburized and annealed to a steel plate having a thickness of 0.30 mm consisting of unavoidable impurities and Fe.
A slurry obtained by mixing MgO powder shown in Table 1 with pure water was applied at a rate of 5 g / m ² per side, dried in an air atmosphere for 10 seconds in a furnace heated to 800 ° C., and wound into a coil. 1150 ℃ × 20hr final finish annealing
Heat flattening treatment was performed to obtain a product.

A steel sheet sample was collected from each product, the magnetic properties were measured, and the appearance of the coating and the incidence of defective portions were obtained from the observation results of the entire length of the coil. For each coil, the MgO sample after drying the MgO slurry was mechanically scraped and collected within 10 minutes after the end of drying from the entire width direction of the dried steel sheet surface, and was collected by a laser diffraction particle size distribution analyzer (HORIB).
A-LA), the particle size distribution was measured to be 90%.
The diameter was determined. Table 2 shows the results. Within the scope of the present invention, both magnetic properties and coating properties are good.

[0032]

[Table 1]

[0033]

[Table 2]

Example 2 C: 0.06%, Si: 3
%, Mn: 0.1%, S: 0.03%, Al: 0.03
%, N: 0.008%, Cu: 0.2%, and the balance is decarburized and annealed to a 0.30 mm-thick steel plate composed of unavoidable impurities and Fe. A slurry was prepared by mixing with pure water, and Ti was added as a film-forming accelerator.
O ₂ was added at 3% of the weight of the MgO powder, the slurry was applied at 5 g / m ² per side, dried in an air atmosphere for 20 seconds in a furnace heated to 800 ° C., and wound into a coil.
The product was subjected to a final finish annealing at 0 ° C. × 20 hours, and a heat flattening treatment was performed to obtain a product.

A steel sheet sample was taken from each product, the magnetic properties were measured, and the appearance of the coating and the incidence of defective portions were obtained from the observation results of the total length of the coil. Further, the MgO sample after drying the MgO slurry in each coil was mechanically scraped and collected from the entire width direction of the surface of the dried steel sheet within 10 minutes after the completion of the drying, and the laser diffraction particle size distribution analyzer (HORIB)
A-LA), the particle size distribution was measured to be 90%.
The diameter was determined. Table 3 shows the results. Within the scope of the present invention, both magnetic properties and coating properties are good.

[0036]

[Table 3]

Example 3 C: 0.08%, Si: 3
%, Mn: 0.08%, S: 0.03%, Al: 0.0
3%, N: 0.008%, Cu: 0.1%, Sn: 0.
A steel sheet having a thickness of 0.23 mm containing 1% and the balance consisting of unavoidable impurities and Fe was decarburized and annealed.
gO powder was mixed with pure water to form a slurry, and TiO ₂ was used as a film formation accelerator in an amount of 3% by weight of MgO powder and Sb.
₂ (SO ₄ ) ₃ was added at 0.2% of the weight of the MgO powder, the slurry was applied at 6 g / m ² on one side, dried in an air atmosphere for 10 seconds in a furnace heated to 800 ° C. and wound into a coil. The product was subjected to a final finish annealing at 1150 ° C. × 20 hours, and subjected to a heat flattening treatment to obtain a product.

A steel sheet sample was taken from each product, the magnetic properties were measured, and the appearance of the coating and the incidence of defective portions were obtained from the observation results of the entire length of the coil. Further, the MgO sample after drying the MgO slurry in each coil was mechanically scraped and collected from the entire width direction of the surface of the dried steel sheet within 10 minutes after the completion of the drying, and the laser diffraction particle size distribution analyzer (HORIB)
A-LA), the particle size distribution was measured to be 90%.
The diameter was determined. Table 4 shows the results. Within the scope of the present invention, both magnetic properties and coating properties are good.

[0039]

[Table 4]

Example 4 MgO powder shown in Table 1 was weighed 1
Each sample was collected in a 750 cm ³ water cooled to a range of 0 to 5 ° C., and stirred at a stirring speed of about 1000 rpm to prepare an MgO slurry. Then, S
i: MgO slurry was dried on both sides of a 0.3 mm-thick steel sheet containing iron as a main component and containing 3%, and then applied so that the weight of MgO powder was 5 g / m ² per side. It was kept for 15 seconds in a heated atmosphere atmosphere in a laboratory furnace. A sufficiently dried MgO powder is scraped off from the surface of the steel sheet using a spatula and collected, and a laser diffraction particle size distribution analyzer (HOR) is used.
The particle size distribution was measured using an LA-500 manufactured by IBA to obtain 9
The 0% diameter was determined. Table 5 shows the results. The laboratory method as described above has confirmed that the MgO powder of the present invention has a 90% diameter of the coated and dried MgO powder smaller than the 90% diameter of the MgO powder before the slurry. Example 1
It is clear from FIG. 3 that when the grain-oriented electrical steel sheet is produced using the MgO of the present invention, excellent magnetic properties and coating properties can be obtained.

[0041]

[Table 5]

[0042]

As described in detail above, if a grain-oriented electrical steel sheet is manufactured using the annealing separator containing MgO as a main component of the present invention, a grain-oriented electrical steel sheet having extremely excellent magnetic properties and coating properties can be obtained. It is possible to manufacture a steel sheet stably.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K026 AA03 AA22 BA08 BB05 CA16 CA18 DA02 DA11 EB11 4K033 AA02 LA01 LA02 MA01 MA02 RA04 TA01 TA02 5E041 AA02 BC01 HB11 HB14 NN18

Claims (7)

[Claims] 1. An annealing separator mainly composed of MgO is applied to a steel sheet in the form of a slurry, applied to a steel sheet, dried, and then subjected to final finish annealing. An annealing separator for grain-oriented electrical steel sheets, wherein the 90% diameter of the annealing separator is smaller than the 90% diameter of the annealing separator before being made into a slurry. 2. The drying of the slurry, wherein the slurry is applied to a steel plate and held in an annealing furnace heated to a temperature of 500 to 900 ° C. for 3 to 40 seconds. Item 4. An annealing separator for a grain-oriented electrical steel sheet according to Item 1. 3. The method according to claim 1, wherein MgO obtained by firing a material containing Mg at 1500 ° C. or higher is used.
An annealing separator for a grain-oriented electrical steel sheet as described. 4. The annealing separating agent for grain-oriented electrical steel sheets according to claim 3, wherein MgO obtained by treating a substance containing Mg by an Arman reactor method is used. 5. The annealing separator according to claim 1, wherein the 90% diameter before the slurry is 100 μm or less. 6. The annealing separator according to claim 1, wherein the CaO content is 0.3% or less. 7. An anneal separating agent containing MgO as a main component is formed into a slurry, applied to a steel sheet, dried, and then subjected to final finish annealing to produce a grain-oriented electrical steel sheet. 500 ~ 900
The method for producing a grain-oriented electrical steel sheet using an annealing separator according to claim 1, wherein the annealing is carried out in an annealing furnace heated to a temperature within the range of 3 to 40 seconds.