JPH05247661A - Production of grain oriented silicon steel sheet having uniform glass film and excellent in magnetic property - Google Patents

Abstract

PURPOSE:To manufacture a grain oriented silicon steel sheet in which glass film of good quality is formed and excellent in magnetic properties by subjecting the cold rolled sheet of high silicon steel to decarburizing annealing to form an oxidized film thickness consisting essentially of SiO2 on the surface, thereafter coating it with a separation agent for annealing having a specified compsn. and executing final finish annealing. CONSTITUTION:A high silicon steel slag is subjected to hot rolling, annealing and cold rolling into a cold rolled sheet having a final sheet thickness, which is thereafter subjected to decarburizing annealing to form an oxidized film thickness contg. SiOS2 by the quantity of 0.5 to 1.3g/m<2> on the surface of the cold rolled sheet. Next, 0.1 to 10 pts.wt. of one or >= two kinds selected from the oxides, sulfides, sulfates, phosphates and borates of Al, Mg, Ca, Na, K, V, B, P, Sb and Sr are added to 100 pts.wt. MgO, which is pulverized by a ultrafinely pulverizing apparatus to uniformize the size of the grains and is subjected to activating treatment into slurry. The surface of the cold rolled sheet subjected to the decarburizing annealing is coated with the slurry as a separation agent for annealing, which is dried, is coiled round a coil and is subjected to final finish annealing. The objective grain oriented silicon steel sheet in which a uniform glass film is formed and excellent in magnetic properties can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, in the production of grain-oriented electrical steel sheet, in the final annealing, forms a thin glass film of high quality and has excellent magnetic properties, and also has a high degree of magnetic domain refinement. The present invention relates to a method for manufacturing an electromagnetic steel sheet.

[0002]

2. Description of the Related Art Generally, grain-oriented electrical steel sheets have a Si content of 4.5% or less.
Hot-rolling the material containing the bottom, annealing and one time or intermediate annealing
The final plate thickness is obtained by cold rolling twice or more. Then N
₂+ H ₂Or H₂PH in a humid atmosphere such as₂O / PH₂The
Control and decarburization annealing to decarburize and SiO₂Subject to
Forming an oxide film. After that, the main component is MgO
Coating roll etc.
Coating, final finishing annealing, secondary recrystallization, purification,
Lath film is formed, and if necessary, insulation film treatment
Heat flattening is done to make the final product. Further
High magnetic flux density grain oriented electrical steel sheet is insulated depending on the application
Laser, press roll, rolling before or after coating agent treatment
Magnetic domain subdivision processing using rolls, tooth profile rolls, scribing, etc.
Go to improve iron loss.

This grain-oriented electrical steel sheet utilizes a phenomenon in which a (110) <001> crystal having a <001> axis grows preferentially by high temperature secondary recrystallization. During this secondary recrystallization process, (110) face crystals with low surface energy grow preferentially and are finely dispersed as an inhibitor in steel A
It is considered that the (110) <001> crystal grows preferentially in order to erode other crystals whose growth is suppressed by 1N, MnS and the like.

Therefore, in order to produce an excellent grain-oriented electrical steel sheet, it is important to control the dispersion of AlN, MnS, etc. in the steel and the control until their decomposition. The change of the inhibitor in the final annealing is affected by the oxide film on the surface of the steel sheet formed by the decarburization annealing, the annealing separator, the thermal cycle in the final finishing annealing, the atmospheric conditions and the like. Among these, the properties of MgO as an annealing separator and the effects of additives are particularly large. These are the change of the surface oxide layer in the temperature rising process in the final annealing, the formation rate in the glass film formation stage, the formation amount,
This is because it affects the quality of the glass film and the like, which affects the stability of the inhibitor.

Annealing Separator MgO and Additives are Decarburization Annealing
SiO formed by₂It reacts with the main oxide layer
Forming a film mainly composed of forsterite
(2MgO + SiO₂→ Mg₂SiO_Four). This glass
In forming the film, MgO is the main component as described above.
SiO of oxide layer formed by decarburization annealing with annealing separator ₂
The quantity and quality of the product have a great influence. That is, Forsterai
The amount of glass coating mainly composed of g
O₂Amount and due to additional oxidation generated during the temperature rising process of finish annealing
SiO₂This is because it is proportional to the total amount of increase. Change
In addition, these factors also affect the quality and uniformity of the glass coating.
It is no exaggeration to say that it depends on

In particular, the glass coating forms Mg ₂ SiO ₄ having a small coefficient of thermal expansion at a high temperature where the steel sheet itself is thermally expanded, and therefore gives tension to the steel sheet during cooling after finishing annealing.
Therefore, forming a glass film with high tension increases the iron loss improving effect due to the tension effect. However, the glass coating itself is a non-magnetic material, and as the thickness increases, the magnetic flux density of the steel sheet decreases, which has the adverse effect of reducing iron loss. In particular, in recent years, a method for improving core loss by subdividing magnetic domains by forming linear, point-like strains, grooves, and alloy layers in a direction substantially perpendicular to the rolling direction by means of optical, mechanical, chemical, etc. Was developed. Also in this case, it is known that the higher the magnetic flux density is, the better the magnetic domain subdivision effect is. Furthermore, the internal oxide layer existing at the interface between the glass coating and the base steel is harmful because it acts as a barrier to the magnetic domain subdivision and hinders the magnetic domain subdivision. In such applications, a thin, high-quality glass coating with no internal oxide layer is formed. It is important to.

Further, in the process of forming the glass film, depending on the time of formation of forsterite, the change in the amount of additional oxidation of the steel sheet, the penetration of N in the atmosphere gas, and the conversely the decrease of N, S, etc. in the steel are affected. Or SiO ₂ in the oxide film
As a result, a decomposition reaction of AlN occurs, which has a great influence on the inhibitor. Thus, the conditions for forming the decarboxylation film layer and the conditions for the annealing separator for the magnetic properties and glass film properties that are most important in determining the commercial value of grain-oriented electrical steel sheet are important, The development of forming technology has become an important development issue for companies in the same industry that manufacture grain-oriented electrical steel sheets.

Among the properties of the annealing separator MgO, factors that influence the formation of the glass film and the stability of the inhibitor include particle size, activity, purity and adhesion, and when applied to steel sheets, hydration The degree of progress, the dispersion state of particles, the density of the coating film, the coating amount, and the like. In addition, as for the additive added as the reaction accelerator, as in the case of MgO,
The particle size and the melting state relating to the reactivity of lowering the melting point for the reaction of O and SiO ₂ include, in particular, the uniform dispersibility on the surface of MgO and the surface of the steel sheet and the addition amount. For this reason, in order to obtain excellent product characteristics, efforts are being made to optimize them together with the conditions for forming the decarboxylated film.

For MgO as an annealing separator, raw materials such as magnesium hydroxide, magnesium carbonate and basic magnesium carbonate are adjusted to crystals having an average particle diameter of 0.2 to 5.0 μm and a primary particle diameter of 700 to It is fired at a high temperature of 1200 ° C. and used as MgO. Usually, this MgO is mixed with an additive as needed, suspended in water to form a slurry, stirred in a tank equipped with a propeller-like stirrer, and applied to a steel plate by a rubber roll method or a spray method. And then dried. At this time, MgO and additives may have an average particle diameter of several μm due to sintering during firing in the manufacturing stage, moisture absorption during storage from the manufacturing stage to the use stage, aggregation due to aging and aggregation during suspension in water. ˜Coarse particles of several tens of μm. Therefore, a contact area and density are small on the surface of the steel sheet after coating and drying, and a coating film having poor adhesion is formed. Furthermore,
In such a case, the viscosity of the slurry becomes low, the coating property at high speed operation becomes poor, and a uniform coating film cannot be obtained.

In particular, when the additive is added, the additive itself also sinters and agglomerates, which adheres to a part of the MgO agglomerate or remains as coarse particles in the coating film or the steel sheet. Since it exists on the surface, the formation reactivity of the forsterite coating is deteriorated or nonuniformity occurs. Such a decrease in reactivity due to sintering and aggregation of the annealing separator component,
As a means for solving the problem due to the decrease in adhesion, a method of controlling the physical properties of MgO at the manufacturing stage to prevent agglomeration has been conventionally used. JP-A-62-15622
In the publication No. 6, a method of activating the outermost surface layer of MgO particles is performed by the present inventors. in this way,
A hydrated layer (Mg (OH) ₂ ) is formed only on the outermost surface layer of MgO obtained by high temperature firing in the MgO production stage, which improves the uniformity of the glass coating and improves the magnetic properties. ing. Further, in Japanese Patent Laid-Open No. 2-267278, the calcined MgO is treated in a vapor-containing gas layer at 100 ° C. or higher, and the OH chemisorption phase on the MgO surface is converted to H ₂ O as MgO.
A method for producing a grain-oriented electrical steel sheet is proposed in which an annealing separator containing 0.8 to 2.5% by weight of MgO is applied to a steel sheet after decarburizing and annealing, and finish annealing is performed. As a result, a grain-oriented electrical steel sheet having a uniform glass coating and excellent magnetic properties can be obtained.

These techniques are for solving the problem of agglomeration of MgO particles at the time of applying the annealing separator slurry, by modifying the surface of the MgO particles after firing by performing a special surface treatment at a high temperature to reduce the surface energy. It lowers and improves the compatibility with water. Due to this effect, it is applied to the steel sheet surface in a well-dispersed state, and a considerable effect is obtained. However, MgO production conditions, problems due to sintering, problems with stability of chemisorbed phases, and the inability to control the dispersed state of the additive cannot be controlled, and further development of new technology is desired.

[0012]

DISCLOSURE OF THE INVENTION The present invention relates to the application of an annealing separating agent to a steel sheet in the production of grain-oriented electrical steel sheet,
An object of the present invention is to provide a new method for adjusting an annealing separator slurry as a solution to the deterioration of the glass film forming property due to a sintered body or an aggregate formed during the production of MgO and an additive and an aggregate formed during the adjustment of the slurry. .. Furthermore, the present invention forms a thin, uniform, and high-quality glass film by specifying the conditions for forming an oxide film during decarburization annealing, which makes it possible to improve the magnetic properties and the iron loss improving effect by controlling magnetic domains. It is an object of the present invention to provide a method of manufacturing a glass grain oriented electrical steel sheet.

[0013]

Means for Solving the Problems In the glass film formation and the secondary recrystallization process from the decarburization annealing of the grain-oriented electrical steel sheet to the application of the annealing separator to the finishing annealing step, the present inventors have a small internal oxide layer, A thin and high quality glass coating was formed and the manufacturing method of the product with excellent magnetic properties was examined. Among them, the research was conducted focusing on the conditions for forming the decarboxylated film and the method of adjusting the annealing separator slurry.

As a method for preparing an annealing separator slurry, an apparatus in which a stirring vessel (tank or the like) is provided with a propeller-shaped or shear-shaped rotating body is generally used. When stirring the slurry with such a device,
The stirring speed and stirring for a long time are required, and sufficient particle dispersion cannot be obtained even if the treatment is carried out under considerably strong stirring conditions. In particular, in such a case, it is difficult to obtain the effect of dispersing and crushing the sintered body and the agglomerate during the production of the annealing separator such as MgO.

Further, the major problem with such a method is that
This is because the slurry temperature rises due to the friction between the particles in the slurry or the friction between the particles and the rotor of the stirrer due to high speed or long time stirring, and the hydrated water content increases. As a result, there is a problem that the glass coating characteristics and magnetic characteristics are deteriorated. Therefore, a large amount of experiments and researches have been conducted on a method in which a sintered body and an agglomerate of an annealing separator can be reliably crushed by treating a slurry for a short time without causing a problem such as an increase in hydrated water content. As a result, as a method for applying an annealing separator which can solve the above problems, a new slurry preparation method utilizing a dispersion crushing technique in a short time by an ultrafine particle pulverizer was developed. As a result, the above problems caused by coarsening of particles due to a sintered body, agglomerate or the like of the conventional annealing separator, non-uniformity of the components and non-uniformity of the coating film have been solved all at once.

The present invention will be described in detail below based on the experimental results. In this experiment, C: 0.075 by weight
%, Si: 3.25%, Mn: 0.066%, S: 0.
024%, Al: 0.029%, N: 0.0078%,
Cu: 0.080%, Sn: 0.080%, high magnetic flux density grain-oriented electrical steel sheet material slab consisting of balance Fe and unavoidable impurities is hot rolled-annealed-cold rolled by a known method to obtain a final sheet thickness of 0. It was 225 mm. After this, N ₂ 25% + H ₂ 75
%, Decarburization annealing was performed at 850 ° C. for 120 seconds in an atmosphere having a dew point of 65 ° C. SiO _{2 in} the oxide film at this time is steel plate 1
It was 0.9 g per m ² . Next, an annealing separator having the composition shown in Table 1 was prepared into a slurry under the conditions shown in the same table.
In stirring the slurry, according to the adjusting method of the present invention, first, stirring was performed at 1000 RPM × 30 minutes with a device having a shear-shaped rotor called a conventional homomixer.
Next, this is supplied from a slurry supply port (hopper) 1 of an ultrafine pulverizer as shown in FIG. 1 and passes between rotating body grinding stones 2 and 3 (the shape of which is shown in FIG. 2) provided with a certain clearance. Then, it was crushed and taken out from the outlet 4.

At that time, the grindstone clearance was crushed under the conditions shown in Table 1. The slurry thus obtained was applied to the decarburized annealed plate, dried and then subjected to finish annealing at 1200 ° C. × 20 Hr. Then as an insulating film agent, 30% colloidal silica _{70l + 50% Al (H 2} PO 4) 3 5
A coating liquid consisting of 0 l + 7 kg of CrO ₃ was applied to obtain a final product. Table 2 shows the results of observing the coating state of the annealing separator, and examining the glass coating and magnetic properties of the product in this experimental process.

[0018]

[Table 1]

[0019]

[Table 2]

As a result of this experiment, the slurry obtained by subjecting the slurry of the present invention to ultrafine particle pulverization was uniformly applied with good adhesion without any sintered aggregate of the annealing separator. Further, the glass coatings after the finish annealing were uniformly and densely formed, and the glass formation amount was appropriate. The magnetic properties were also very good. On the other hand, in the case where only the homomixer of the comparative example was stirred, many sintered bodies and aggregates of the annealing separator were found, resulting in a non-uniform coating film and significantly poor adhesion. In this case, there were many non-uniform portions of the glass coating, which was considerably thinner than in the present invention. In addition, the magnetic characteristics were considerably poor in both magnetic flux density and iron loss value as compared with the present invention.

Next, the reasons for limitation of the present invention will be described. INDUSTRIAL APPLICABILITY The present invention is applied when an annealing separator is applied to the surface of a steel sheet after decarburization annealing of a grain-oriented electrical steel sheet, dried and wound into a coil, and is applied in the subsequent steps including the decarburization step. .. 0 oxide film weight SiO ₂ of the steel sheet in the decarburization annealing of the present invention.
It is in the range of 5 to 1.3 g / m ² . Forsterite amount formed by finish annealing is basically proportional to the total amount of SiO ₂ SiO ₂ amount generated by additional oxidation during formed SiO ₂ amount and final annealing at decarburization annealing. In the usual manufacturing process, if the film of forsterite is made thin, the amount of SiO ₂ formed during decarburization annealing must be reduced, but in order to do so, the annealing temperature, dew point, etc. must be lowered. Inevitably, firelite (Fe
₂ SiO ₄ ) and the like are reduced, and the reactivity of forming a glass film is extremely lowered. Therefore, in the prior art, the annealing separator M
Although methods such as strictly controlling the conditions of gO and additives have been considered, it has been very difficult to form a thin, good-quality glass film useful for magnetic properties.

According to the present invention, S in the decarboxylated film as described above is used.
Even under conditions where the amount of iO ₂ was reduced, the development of coating conditions for the annealing separator significantly improved the film forming reactivity,
It makes it possible to form a thin, good quality glass coating. The amount of SiO _{2 in} the oxide film during decarburization annealing is 0.
If it is less than 5 g / m ² , the amount of forsterite formed is small, and a good quality film cannot be obtained uniformly even with the technique of the present invention. In addition, the decrease in the inhibitor during the temperature rise of the finish annealing is accelerated, and in the extreme case, the orientation of the secondary recrystallized grains becomes worse. On the other hand, if it exceeds 1.3 g / m ² , the amount of forsterite formed becomes too large,
Magnetism deteriorates due to an increase in the internal oxide layer called subscale. In particular, an ultra-low iron loss material cannot be obtained when the magnetic domains are subdivided, which is the feature of the present invention. Further, when the amount of SiO ₂ exceeds 1.3 g / m ² , lower oxides such as (Fe, Mn) ₂ SiO ₄ in the oxide film increase, causing film defects such as pinholes and scales peculiar to the peroxidation phenomenon. It tends to occur.

The most characteristic feature of the present invention is the following method for preparing an annealing separator slurry. As a method for uniformly dispersing the ultrafine particles of the slurry, an ultrafine particle pulverizer is used. As a result, surface activation can be obtained by dispersing and crushing ultrafine particles of the annealing separator, which cannot be solved by the conventional apparatus provided with a propeller-shaped or shear-shaped rotating body. The dispersion treatment by the ultra-fine particle pulverizer is performed by an apparatus provided with a rotary grindstone as shown in FIG. 1 during the process of adjusting the annealing separator slurry and before applying it to the steel plate after the adjustment. The grinding and crushing conditions at this time are controlled by changing the surface shape of the grindstone, the clearance of the grindstone, the concentration of the annealing separator, and the like, while controlling the processing flow rate.

These setting conditions are determined according to the sintering state, cohesiveness, etc. of the supplied annealing separator. This ultra-fine pulverization treatment increases hydrated water similarly to mixing in a conventional stirring device. It is preferable to perform the cooling while adjusting the liquid temperature of the slurry, and the ultrafine particle pulverization treatment is 1 to
About 10 passes are preferable. Under such conditions, the hydrated water content does not increase and the effect is great.

In fact, in the ultrafine particle crushing process, even a considerably strong sintered body or agglomerate can be processed in approximately 70 to 80 in one pass.
Ultra-fine graining is completed up to%. In applying the ultrafine particle pulverizer in the present invention, adjustment of the annealing separator slurry-
It is preferable to use it together with an ordinary stirring device before coating the steel sheet. That is, as described above, the ultrafine particle pulverization treatment is completed in an extremely short time, and reaggregation does not occur even if a normal stirring for a long time is performed thereafter, so that the combined use with the normal stirring is sufficient. For this reason, when industrially applied, the slurry is circulated to the coil while circulating the slurry by performing one or more ultra-fine atomization treatments with a device installed in a bypass or connected to a normal agitator equipped with a slurry agitator. It is best to carry out the coating work.

In preparing the annealing separator of the present invention, the annealing separator is Al, Mg, C based on 100 parts by weight of MgO.
a, Na, K, B, V, P, Sb, Sr and other oxides, sulfides, sulfates, phosphates, borates, etc. Used. These additives act as reaction accelerators or inhibitor enhancers and stabilizers in the forsterite formation reaction.

The effect varies depending on the form of each additive compound, but if the amount added is less than 0.1 part by weight, a sufficient effect cannot be obtained. On the other hand, if the amount is more than 10 parts by weight, the melting point is lowered too much at the time of forming the glass film, or a peroxide phenomenon occurs to cause defects such as shimofuri and scale. Further, the additional oxidation during finish annealing increases the amount of SiO ₂ in the oxide film, resulting in an increase in the amount of forsterite formed or an increase in the internal oxide layer, which is a cause of magnetic deterioration, which is not preferable.

Next, the reason why the glass film is uniformly formed and the magnetic characteristics are improved by the present invention will be described. In the present invention,
Under the conditions in which the amount of SiO ₂ in the oxide film during decarburization annealing is controlled, the dispersion state, adhesion state, uniformity, etc. of the annealing separator applied to the surface are improved. At this time, compounds such as oxides, sulfides, sulfates, phosphates, borates, etc., which are added if necessary, are also finely dispersed and crushed at the same time to form ultrafine particles.
It is evenly distributed on the gO surface and the steel plate surface. As a result, high reactivity and uniformity of reaction, which were not obtained by the conventional technology, are obtained, the forming property of the glass film is improved, a thin and high-density glass film is formed, and the inhibitor Improve the magnetism by controlling the strengthening and stabilization appropriately. Further, as a result of forming this high-quality glass coating, the iron loss improving effect is enhanced by the reduction of the coating thickness and the reduction of the barrier at the time of domain wall movement in the domain segmentation treatment.

[0029]

【Example】

Example 1 C: 0.075% by weight, Si: 3.30%, Mn:
0.062%, S: 0.025%, Al: 0.026
%, N: 0.0078%, the balance being Fe and inevitable impurities, a material for high magnetic flux density grain-oriented electrical steel sheet was treated by a known method to obtain a cold rolled sheet having a final sheet thickness of 0.22 mm. This steel plate is N ₂ 25% + H ₂ 75% and the dew point is changed to 850 ° C.
Decarburization annealing was performed for 120 seconds to manufacture coils having different amounts of SiO ₂ in the oxide film.

Then, as shown in Table 3, the steel sheet was coated by changing the composition of the annealing separator and the adjusting condition of the slurry, wound, and subjected to final finishing annealing at 1200 ° C. × 20 Hr. After this, 50l of 50% phosphoric acid Al as an insulating coating agent
+ 30% colloidal silica 70l + CrO ₃ 7kg was applied and a tensioning type coating agent was applied, and 850 ° C x 3
A baking process was performed for 0 seconds. Table 4 shows the results of an examination of the application state of the annealing separator, product characteristics, etc. in this test process.

[0031]

[Table 3]

[0032]

[Table 4]

As a result, in all of the products according to the present invention, the annealing separator was applied uniformly, finely and with good adhesion.
On the other hand, when only the homomixer of Comparative Example was used for stirring, many coarse particles were observed, the particles were uneven, and the graininess was very large. Further, the adhesiveness to the steel plate was also very poor, and the situation was such that peeling was likely to occur. Regarding the characteristics after finish annealing, a high-quality glossy glass film was uniformly formed in the present invention, and very good magnetic characteristics were obtained. In particular, SiO ₂ after decarburization annealing
When the amount formed was 0.8 g or less, remarkably good characteristics were obtained. However, in the comparative example, the glass coating was thin and formed nonuniformly, and the magnetic characteristics were considerably worse than those of the present invention.

Example 2 The same material as in Example 1 was used as a starting material, and processed in the same manner, and cold rolled to a final plate thickness of 0.20 mm. This coil is N ₂ 25
% + H ₂ 75%, decarburization annealing was performed in an atmosphere with a dew point of 65 ° C., the annealing separator composition and slurry adjusting conditions were changed as shown in Table 5, and the steel sheet was applied and finish annealing was performed at 1200 ° C. × 20 Hr. Then, in the same manner as in Example 1, an insulating coating material was applied and baked. A linear distortion was applied to this product at a distance of 5 mm in the direction perpendicular to the rolling direction using a YAG laser, and magnetic domain subdivision processing was performed.

Table 6 shows the particle size of the annealing separating agent slurry, the coating state, the coating properties of the product, and the magnetic properties in this test.

[0036]

[Table 5]

[0037]

[Table 6]

As a result, according to the present invention, the particle size in the slurry was extremely fine, the surface of the steel sheet was finely and uniformly applied after the application, and the adhesion to the steel sheet was strong and good. In addition, the glass coating film after finishing annealing was formed in a uniform and glossy quality. Regarding the magnetic properties, the magnetic flux density and iron loss value according to the present invention were good, and a particularly good improvement effect was obtained after the magnetic domain refining treatment. On the other hand, under the conditions of the comparative example, the particle size was considerably large due to the agglomerated particles in the slurry, and the surface was rough and the adhesion was poor after the application to the steel sheet. For this reason, the glass films after finish annealing were all thin and uneven. Also, the magnetic properties were considerably worse than those of the present invention.

[0039]

According to the present invention, when the annealing separator is applied to the steel sheet, the slurry is crushed by the ultrafine particle crushing device to disperse the sintered body and the agglomerates into the ultrafine particles, so that the steel sheet surface is evenly distributed. It is applied with good adhesion, whereby the reactivity of glass film formation is significantly improved. Further, according to the present invention, by controlling the amount of steel sheet oxidation during decarburization annealing, a thin, uniform and high-quality glass film is formed, which can improve the magnetic properties. Further, the steel sheet thus obtained has a large magnetic domain refining effect, and good iron loss characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of an ultrafine particle crushing device of the present invention.

FIG. 2 is a diagram showing a typical example of the shape of a grindstone.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Sato 59 Nittetsu Plant Design Co., Ltd., 46 Nakahara, Tobata-ku, Kitakyushu, Fukuoka

Claims (2)

[Claims] 1. A material for a grain-oriented electrical steel sheet is cold rolled to a final thickness, decarburized and annealed to form an oxide film layer containing SiO ₂ as a main component, and an annealing separator containing MgO as a main component is applied. Then, in a process consisting of performing finish annealing, 0.5 to 1.3 g / m of SiO ₂ in the steel sheet oxide film formed during decarburization annealing
Annealing as ² , when applying the annealing separating agent, after the annealing separating agent slurry suspended in water is subjected to uniform fineness and activation treatment of particles with an ultrafine pulverizer, coating, drying, coil A method for producing a grain-oriented electrical steel sheet which has a uniform glass coating formed by winding and final annealing and has excellent magnetic properties. 2. An annealing separator composition is Al, Mg, Ca, Na, K, V, B, P, S based on 100 parts by weight of MgO.
The homogeneous composition according to claim 1, wherein 0.1 to 10 parts by weight of one or more selected from oxides such as b and Sr, sulfides, sulfates, phosphates, borates, etc. is added. Method for producing grain-oriented electrical steel sheet with excellent glass properties and excellent glass coating.