JP2003268451A - Method for manufacturing grain-oriented electromagnetic steel sheet with high magnetic flux density and mirror plane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve iron loss by enhancing the integration of the crystal orientation in a grain-oriented electromagnetic steel sheet with a mirror plane. <P>SOLUTION: In a process for manufacturing the grain-oriented electromagnetic steel sheet, which cold-rolls a steel strip containing, by mass, 0.8-4.8% Si, 0.003-0.1% C, 0.012-0.05% acid-soluble Al, and N≤0.01%, decarburization anneals it, applies a separation agent for annealing on it, and finishing anneals it, a method for manufacturing the grain-oriented electromagnetic steel sheet with high magnetic flux density and the mirror plane is characterized by carrying out the decarburization annealing in an atmosphere having such a degree of oxidation as not forming Fe-based oxides, to form an oxide layer mainly consisting of silica on a steel sheet surface, and then applying the separation agent for annealing mainly consisting of alumina, and by adding a boron compound to the agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a grain-oriented electrical steel sheet mainly used as an iron core of a transformer or other electric equipment. In particular, the iron loss characteristics are improved by effectively finishing the surface and increasing the magnetic flux density.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets are used as magnetic iron cores in many electric devices. The grain-oriented electrical steel sheet contains Si in an amount of 0.8 to 4.8%, and has a crystal grain orientation of {11
It is a steel plate highly integrated in the 0} <001> direction. The magnetic properties are required to have a high magnetic flux density (represented by B8 value) and a low iron loss (represented by W17 / 50 value). Particularly in recent years, there has been an increasing demand for reduction of power loss from the viewpoint of energy saving.

In response to this demand, a technique for subdividing magnetic domains has been developed as a means for reducing the iron loss of grain-oriented electrical steel sheets. In the case of a laminated iron core, a method of irradiating a steel beam after finish annealing with a laser beam to locally apply a minute strain to subdivide a magnetic domain to reduce iron loss is disclosed in, for example, JP-A-58-26405. Has been done. However, by observing the movement of these magnetic domains, it was found that there were magnetic domains that were pinned due to the unevenness of the glass coating on the surface of the steel sheet and did not move. Therefore, in order to further reduce the iron loss value of the grain-oriented electrical steel sheet, it is important to eliminate the pinning effect due to the unevenness of the glass coating on the surface of the steel sheet that inhibits the movement of the magnetic domain together with the subdivision of the magnetic domain. To be

For that purpose, it is effective not to form a glass coating on the surface of the steel sheet which hinders the movement of magnetic domains. As a means for this, a method of forming a glass film by using coarse and highly pure alumina as an annealing separator is disclosed in, for example, US Pat. No. 3,785,882. However, with this method, the inclusions just below the surface cannot be eliminated, and the improvement margin of iron loss is only 2% at W15 / 60.

As a method of controlling the inclusions just below the surface and achieving a mirror surface of the surface, a method of performing chemical polishing or electrolytic polishing after finish annealing is disclosed in, for example, Japanese Patent Laid-Open No. 64-8.
It is disclosed in Japanese Patent No. 3620. However, chemical polishing, electrolytic polishing, etc. can process a small amount of material at the laboratory level, but for industrial scale processing, chemical concentration control, temperature control, and provision of pollution equipment are required. There is a big problem in terms of such things, and it has not yet been put to practical use.

On the other hand, in order to improve iron loss, it is effective to increase the degree of orientational integration of crystal grains, and as a method therefor, Taguchi / Sakakura (Japanese Patent Publication No. 40-15644), Komatsu et al. (Japanese Patent Publication No. 62). -45285 gazette) etc., the method of using the nitride of Al as an inhibitor is disclosed. However, when the method of US Pat. No. 3,785,882 using alumina as an annealing separator is applied to these methods using Al nitride as an inhibitor, secondary recrystallization becomes unstable, and iron loss Cannot achieve improvement.

The present inventors have found these problems, namely,
(1) Taguchi and Sakakura (Japanese Patent Publication No. 40-15644),
Secondary recrystallization of high magnetic flux density materials such as Komatsu et al. (Japanese Patent Publication No. 62-45285) using Al nitrides as inhibitors is unstable, and (2) subsurface inclusions are present. The measures to solve the problem were examined.

As a result, it was found that the secondary recrystallization becomes unstable due to the rapid weakening of the Al nitride inhibitor during the finish annealing when the glass film is not formed. By carefully studying the countermeasures against this, the dew point of decarburization annealing is controlled, and Fe-based oxides (Fe ₂ SiO ₄ , FeO) are formed in the oxide layer formed during decarburizing annealing.
Etc. are not formed, and the decarburized annealed plate on which such an oxide layer is formed is coated with an annealing separator containing alumina as a main component in the form of a water slurry, or is dry-coated by an electrostatic coating method or the like. It was found that the secondary recrystallization can be stabilized by this method and the surface after finish annealing can be mirror-finished to greatly reduce the iron loss (Japanese Patent Laid-Open No. 7-118750). Also, it is effective to add interfacial segregation elements to the steel and concentrate these elements on the surface before secondary recrystallization in order to control the inhibitor and stabilize the secondary recrystallization behavior. Was found (JP-A-6-256850).

[0009]

The present invention further enhances the degree of integration of crystal orientation due to secondary recrystallization by adjusting the additive of the annealing separator containing alumina as a main component, thereby reducing the iron loss of the product. It provides a way to achieve improvement.

[0010]

In order to solve the above problems, the present invention has the following structures. (1) By mass, contains Si: 0.8 to 4.8%, C: 0.003 to 0.1%, acid-soluble Al: 0.012 to 0.05%, N ≦ 0.01%. After cold rolling and decarburizing annealing of a steel strip, in a method for producing a grain-oriented electrical steel sheet in which an annealing separator is applied and finish annealing is performed, decarburizing annealing is performed in an atmosphere gas having an oxidation degree that does not form an Fe-based oxide, A magnetic flux density characterized by applying an annealing separator containing alumina as a main component after forming an oxide layer containing silica as a main component on the surface of a steel sheet, and adding a boron compound into the annealing separator. Of high specular grain oriented electrical steel sheet. (2) The method for producing a specular grain-oriented electrical steel sheet having good magnetic properties according to the above (1), characterized in that one or more of Sn or Sb or a compound thereof is added to the annealing separator. (3) Sn or Sb as an element in steel is 0.03 by mass.
~ 0.15% is added, The method for producing a specular grain-oriented electrical steel sheet having good magnetic properties according to the above (1) or (2). (4) The amount of water brought in during the finish annealing of the annealing separator is 1.
5% or less, the above (1) to (3)
2. A method for producing a specular grain-oriented electrical steel sheet having good magnetic properties according to any one of 1. (5) In the finish annealing step, the heating rate in the secondary recrystallization temperature range of 1000 to 1100 ° C. is set to 20 ° C./hr or less, and the secondary recrystallization is performed in this temperature range, (1) to (4) The manufacturing method of the mirror-oriented grain-oriented electrical steel sheet with high magnetic flux density of any one of 1).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
By mass, Si: 3.3%, Mn: 0.1%, C: 0.0
6%, S: 0.007%, acid-soluble Al: 0.028
%, N: 0.008% of a silicon steel slab was heated at 1150 ° C., and then hot rolled to a plate thickness of 2.0 mm. This hot rolled sheet 1
After annealing at 120 ° C. for 2 minutes, it was cold-rolled to a final plate thickness of 0.22 mm. This cold-rolled sheet was subjected to an atmospheric gas oxidation degree (PH ₂ O
/ P H ₂ ): Decarburization annealing was performed at 830 ° C. in a wet gas of 0.1. After that, the amount of nitrogen was reduced to 0.
A nitriding treatment was performed so that the content was 02%.

To these samples, 0 to 3% of B ₂ O ₃ was added to an annealing separator containing alumina as a main component, and the resulting mixture was applied and dried in the form of a water slurry. The coating amount after drying was 20 g / m ² . Finishing annealing has an oxidation degree (P H ₂ O / P H ₂ ): 0.0
10 ° C./h in a nitrogen-hydrogen mixed gas atmosphere of 0016
heating to 1200 ° C at r, and the degree of oxidation (P H ₂ O / P
H ₂ ): switch to 0.000039 hydrogen gas 120
Annealed at 0 ° C for 5 hours. FIG. 1 shows the magnetic flux densities (B8) of the products obtained by subjecting these samples to the tension coating treatment and the magnetic domain refinement treatment by laser irradiation.

From FIG. 1, 0 to 0.2% of B ₂ O ₃ was added,
In particular, it is understood that the magnetic flux density (B8) of the product is improved by adding 0.5% or more. When the effect of B ₂ O ₃ on the secondary recrystallization was investigated, the amount of B in the steel increased in the secondary recrystallization temperature range of 1000 ° C. and the grain growth suppression effect of the matrix was strengthened. It was confirmed that Thus magnetic flux density (B8) was improved, the B ₂ O ₃ was added to annealing separator decomposed decomposed S is presumed to be due to enhanced penetration and the inhibitor effect in the steel.

Next, an embodiment of the present invention will be described. As a basic manufacturing method, a manufacturing method based on a low temperature slab using (Al, Si) N by Komatsu et al. As a main inhibitor capable of manufacturing a product having a high magnetic flux density (B8) (eg Japanese Patent Publication No. 62-48585). , Or Taguchi / Sakakura et al., A manufacturing method based on high-temperature slab heating using AlN and MnS as main inhibitors (for example, Japanese Patent Publication No. 40-15644).
Issue).

Si is an important element for increasing electric resistance and reducing iron loss. If the content exceeds 4.8%, the material tends to crack during cold rolling, making rolling impossible. On the other hand, if the amount of Si is reduced, α → γ transformation occurs during finish annealing, and the crystal orientation is impaired. Therefore, the lower limit is 0.8%, which does not substantially affect the crystal orientation.

When C remains, it causes deterioration of product characteristics (iron loss), so it is necessary to suppress C to 0.003% or less. However, if the C content is lowered in the steelmaking stage, coarse {100} elongated grains are present in the crystal structure of the hot rolled sheet,
It adversely affects secondary recrystallization. Further, from the viewpoint of controlling precipitates and primary recrystallization texture, it is necessary to add C to some extent in the steelmaking stage. Therefore, in the steelmaking stage,
003% or more, preferably 0.02 in which α / γ transformation occurs
% Or more is desirable. On the other hand, even if added in excess of 0.1%, the effects on the crystal structure, precipitates, etc. described above are almost saturated and the time required for decarburization becomes long, so 0.1%
Is the upper limit.

Acid-soluble Al is an essential element for binding to N to function as AlN or (Al, Si) N as an inhibitor. Higher magnetic flux density 0.0
The range is 12 to 0.05%.

When N is added in excess of 0.01% during steelmaking, N causes vacancies in the steel sheet called blisters, so 0.0
The upper limit is 1%.

Mn and S are essential elements to function as MnS as an inhibitor in the manufacturing method based on high temperature slab heating by Taguchi, Sakakura and others. Higher magnetic flux density, Mn: 0.03 to 0.15%, S: 0.01 to
The limiting range is 0.05%. In addition, S is desirable to be 0.015% or less because it adversely affects the magnetic properties in a manufacturing method based on a low temperature slab using (Al, Si) N as a main inhibitor by Komatsu et al.

Sn and Sb are elements effective in segregating on the surface of the steel sheet to suppress decomposition of the inhibitor during finish annealing and to stably produce a product having a high magnetic flux density. 0.
It is desirable to add 03 to 0.15%. Below this lower limit, the inhibitory decomposition inhibiting effect is small, and a substantial magnetic flux density improving effect cannot be obtained. Moreover, when exceeding this upper limit, the inhibitory effect of inhibitor decomposition is saturated, and
In the manufacturing method based on a low temperature slab that uses (Al, Si) N as a main inhibitor by Komatsu et al., Nitriding into a steel sheet becomes difficult, and secondary recrystallization may become unstable.

Cr improves the oxide layer of decarburization annealing and is an effective element for forming a glass film, and if necessary, 0.03 to
It is desirable to add 0.2%. In addition, a small amount of B,
The inclusion of Bi, Cu, Se, Pb, Ti, Mo, etc. in the steel does not impair the gist of the present invention.

The molten steel having the above components is formed into a hot-rolled sheet by a usual process, or the molten steel is continuously cast into a ribbon. The hot-rolled sheet or the continuously cast ribbon is immediately or cold-rolled after annealing for a short time. The above annealing is 750
The annealing is performed in a temperature range of ~ 1200 ° C for 30 seconds to 30 minutes, and this annealing is effective for enhancing the magnetic properties of the product. Therefore, it is advisable to decide whether or not to accept the product in consideration of the characteristic level and cost of the desired product. The cold rolling is performed once or by a plurality of cold rolling processes in which intermediate annealing is performed to obtain a predetermined final plate thickness. In order to increase the magnetic flux density (B8) of the product, basically, as disclosed in Japanese Patent Publication No. 40-15644, the final cold rolling reduction should be 80% or more.

The material after cold rolling is subjected to decarburization annealing in a wet hydrogen atmosphere in order to remove carbon contained in steel. In this decarburization annealing, Fe-based oxide (Fe ₂ Si
Annealing at a low degree of oxidation that does not form lower oxides such as O ₄ and FeO is an essential requirement for achieving a mirror-finished surface. For example, 80 where decarburization annealing is usually performed
In the temperature range of 0 to 850 ° C., the generation of Fe-based oxides can be suppressed by adjusting the oxidation degree of the atmospheric gas (P H ₂ O / P H ₂ ): 0.15 or less. However, if the degree of oxidation is lowered too much, the decarburization rate will become slow. Considering both of them, in this temperature range, the degree of oxidation of the atmospheric gas (PH ₂ O / PH ₂ ): 0.01 to
The range of 0.15 is preferable.

A manufacturing method using (Al, Si) N as a main inhibitor for this decarburized annealed plate (see, for example, Japanese Patent Publication No. 62-
No. 45285), a nitriding treatment is performed. The method of this nitriding treatment is not particularly limited, and there is a method of performing it in an atmosphere gas having a nitriding ability such as ammonia.
Quantitatively 0.005% or more, preferably N / acid soluble A
Nitriding may be performed so that the ratio of l is 2/3 or more.

These decarburized and annealed sheets are coated with an annealing separator containing alumina as a main component in a water slurry or dry coated by an electrostatic coating method and wound into a coil.
At that time, it is effective to bring the moisture content of the annealing separating agent containing alumina as the main component to 1.5% or less in order to stabilize the secondary recrystallization and achieve the mirror surface. When coating and drying with water slurry, BET of alumina is used to control the water content brought in after coating and drying of the annealing separator.
The water temperature, stirring time, and the like when making the water slurry may be managed together with the value, particle size, and the like.

As an annealing separator, Japanese Patent Application No. 2001-22
As disclosed in No. 0228, using a powder obtained by mixing alumina and magnesia having a controlled BET specific surface area in a certain ratio range as an annealing separator is an effective method for promoting the mirroring of the surface. is there. Further, if there is a concern that the adhesion to the steel sheet is insufficient, or if there is a problem in sedimentation in a slurry state, a thickener or the like may be added as necessary.

A boron compound is added to this annealing separator.
That is the requirement of the present invention. Added in annealing separator
Boron compounds decompose during finish annealing, and decomposed boron is steel.
Invades inside and acts as an inhibitor, magnetic flux density
It is thought to improve (B8). As a boron compound
Is B₂O₃, H₃BO₃, Na₂B_FourO₇, Na₂B
_FourO₇・ 10H₂A compound such as O may be used. these
It is also possible to add and use a plurality of boron compounds.
When using alumina as the main component of the annealing separator,
No forsterite film is formed on the steel plate surface
Thus, the added B efficiently penetrates into the steel sheet.

In order to improve the magnetic flux density, the added boron compound should be added in an amount such that the B content is 0.0005% or more with respect to the steel sheet. The upper limit of the amount added is not particularly limited, but the effect will be saturated if about 0.004% is added. Further, if too much is added, the secondary recrystallization completion temperature of finish annealing becomes too high, so the heating rate in the secondary recrystallization temperature range of 1000 to 1100 ° C. is slowed to adjust the secondary recrystallization completion temperature. There is a need. Taking these into consideration, it is preferable to add sulfide as an S content in an amount of 0.0005 to 0.004% to the steel sheet.

Furthermore, one or more of Sn or Sb and their compounds may be added to the annealing separator.
This is an effective measure. It is considered that when Sn and Sb segregate on the surface, they serve as a denitrification barrier, and Al nitride inhibitors such as AlN and (Al, Si) N stabilize to the secondary recrystallization temperature range.

The decarburized and annealed sheets are laminated and finish annealed to carry out secondary recrystallization and purification of the nitride. It is possible to maintain the secondary recrystallization at a constant temperature as disclosed in JP-A-2-258929, or to perform the secondary recrystallization within a predetermined temperature range by means such as controlling the heating rate. , Is effective in increasing the magnetic flux density (B8) of the product.

After the completion of the secondary recrystallization, in order to purify nitrides and reduce the surface oxide film, 1100 ° C. with 100% hydrogen.
Anneal at the above temperature. In this case, it is preferable that the dew point of the atmospheric gas is low. After the finish annealing, the surface is subjected to tension coating treatment and, if necessary, magnetic domain subdivision treatment such as laser irradiation.

[0032]

[Example] [Example 1] Si: 3.3% by mass, C:
0.06%, acid-soluble Al: 0.026%, N: 0.0
08%, Mn: 0.1%, S: 0.007%, Cr:
A silicon steel slab containing 0.1% and Sn: 0.07% was heated at 1150 ° C. and then hot-rolled to a plate thickness of 2.0 mm.
The hot rolled sheet was annealed at 1100 ° C. for 2 minutes and then cold rolled to a final sheet thickness of 0.22 mm. This cold-rolled sheet was subjected to an oxidation degree (P H ₂
O / P H ₂ ): Decarburization in wet gas of 0.1 840
It was annealed at 90 ° C. for 90 seconds for primary recrystallization. Then, by annealing in an ammonia atmosphere, the nitrogen content is reduced to 0.02%.
Intensification of inhibitor was carried out.

The following annealing separators (A) to (F) were applied to this steel sheet in the form of a water slurry and dried. (A) Al ₂ O ₃ , (B) Al ₂ O ₃ + 1% H ₃ B
O ₃ , (C) Al ₂ O ₃ + 1% Na ₂ B ₄ O ₇ · 10H
₂ O, (D) Al ₂ O ₃ + 0.5% B ₂ O ₃ , (E) A
l ₂ O ₃ + 0.5% B ₂ O ₃ + 2% Sb ₂ (S
O ₄ ) ₃ , (F) Al ₂ O ₃ + 0.5% B ₂ O ₃ + 1%
Sn.

These samples were laminated and subjected to finish annealing. Finish annealing is 10 ℃ / hr in mixed gas of nitrogen and hydrogen
It is heated up to 1200 ° C and switched to hydrogen gas 1200
Annealed at 20 ° C for 20 hours. After that, a tension coating treatment was performed and then laser irradiation was performed to subdivide the magnetic domains. The magnetic properties of the obtained product are shown in Table 1.

Table 1 Sample code Magnetic flux density Iron loss W17 / 50 Remarks B8 (T) (W / kg) A 1.937 0.70 Comparative example B 1.955 0.62 Inventive example C 1.949 0. 64 Invention Example D 1.958 0.61 Invention Example E 1.955 0.61 Invention Example F 1.953 0.62 Invention Example

It can be seen that by adding the boron compound, secondary recrystallization is stably developed, the magnetic flux density (B8) is improved, and the iron loss (W17 / 50) is reduced. Moreover, S
It can be seen that adding n or Sb or one or more of these compounds to the annealing separator is also an effective strategy.

Example 2 The decarburizing / nitriding plate used in Example 1 was coated with the following annealing separators (A) to (D) and dried. (A) Al ₂ O ₃ , (B) Al ₂ O ₃ + 0.5% B
₂ O ₃ , (C) Al ₂ O ₃ + 1% B ₂ O ₃ , (D) Al
₂ O ₃ + 3% B ₂ O ₃ . These samples were laminated and subjected to finish annealing. Finish annealing is performed in a mixed gas of nitrogen and hydrogen,
(1) Heat to 1200 ° C. at a heating rate of 20 ° C./hr and (2) 25 ° C./hr and switch to hydrogen gas 1200
Annealed at 20 ° C for 20 hours. After that, a tension coating treatment was performed and then laser irradiation was performed to subdivide the magnetic domains. The magnetic properties of the obtained product are shown in Table 2.

Table 2 Heating rate Sample code Magnetic flux density Remarks (° C / hr) B8 (T) 20 A 1.933 Comparative example 20 B 1.953 Inventive example 20 C 1.952 Inventive example 20 D 1.955 Inventive Example 25 A 1.931 Comparative Example 25 B 1.951 Inventive Example 25 C 1.949 Inventive Example 25 D 1.924 Comparative Example

By adding the boron compound, the secondary recrystallization is stably developed and the magnetic flux density (B8) is improved, but if it is added too much as in the case of (D), the heating rate of finish annealing is increased. It can be seen that when the temperature is as fast as 25 ° C./hr, the secondary recrystallization completion temperature becomes too high and the magnetic flux density decreases.

Example 3 By mass, Si: 3.2%,
C: 0.08%, acid-soluble Al: 0.025%, N:
0.009%, Mn: 0.08%, Cu: 0.09%,
A silicon steel slab containing S: 0.025% and Sn: 0.1% was heated at 1350 ° C. and then hot-rolled to a plate thickness of 2.0 mm. 0.22 m after annealing this hot rolled sheet at 1120 ° C
Cold rolled to m thickness. This cold-rolled sheet has an oxidation degree (P H ₂ O / P H
₂ ): 0.13 in wet gas, also for decarburization in wet gas 8
It was annealed at 50 ° C. for 90 seconds to perform primary recrystallization.

The following annealing separators (A) to (F) were applied to this steel sheet in the form of water slurry and dried. (A) Al ₂ O
₃ , (B) Al ₂ O ₃ + 1% H ₃ BO ₃ , (C) Al ₂
O ₃ + 1% Na ₂ B ₄ O ₇ · 10H ₂ O, (D) Al ₂
O ₃ + 0.5% B ₂ O ₃ , (E) Al ₂ O ₃ + 0.5%
B ₂ O ₃ + 2% Sb ₂ (SO ₄ ) ₃ , (F) Al ₂ O ₃
+ 0.5% B ₂ O ₃ + 1% Sn. These samples were laminated and subjected to finish annealing. The finish annealing was performed by heating to 1200 ° C. at 10 ° C./hr in a mixed gas of nitrogen and hydrogen, switching to hydrogen gas and annealing at 1200 ° C. for 20 hours. After that, a tension coating treatment was performed and then laser irradiation was performed to subdivide the magnetic domains. Table 4 shows the magnetic properties of the obtained product.

Table 4 Sample code Magnetic flux density Iron loss W17 / 50 Remarks B8 (T) (W / kg) A 1.935 0.71 Comparative example B 1.953 0.62 Inventive example C 1.946 0. 64 Present Invention Example D 1.952 0.62 Present Invention Example E 1.955 0.61 Present Invention Example F 1.953 0.62 Present Invention Example

It can be seen that by adding the boron compound, secondary recrystallization is stably developed, the magnetic flux density (B8) is improved, and the iron loss (W17 / 50) is reduced. Moreover, S
It has been found that adding one or more of n or Sb and their compounds to the annealing separator is also an effective strategy.

[0044]

According to the present invention, by increasing the degree of integration of crystal orientation by secondary recrystallization and improving the mirror surface state of the surface, a unidirectional electrical steel sheet having good magnetic properties can be manufactured at low cost. it can.

[Brief description of drawings]

FIG. 1 shows the effect of boron compounds (B ₂ O) on the magnetic flux density (B 8).
_The figure which shows the influence of the addition amount of ₃ ).

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Claims (5)

[Claims] 1. By mass, Si: 0.8 to 4.8%, C: 0.003 to 0.1%, acid-soluble Al: 0.012 to 0.05%, N ≤ 0.01%. In the method for producing a grain-oriented electrical steel sheet, in which the steel strip containing is cold-rolled / decarburized and annealed, and then an annealing separator is applied and finish annealing is performed, the decarburization / annealing is performed in an atmosphere gas with an oxidation degree that does not form an Fe-based oxide. And forming an oxide layer containing silica as a main component on the surface of the steel sheet, applying an annealing separating agent containing alumina as a main component, and adding a boron compound into the annealing separating agent. A method for manufacturing a mirror-oriented electrical steel sheet having a high magnetic flux density. 2. The method for producing a grain-oriented electrical steel sheet with good magnetic properties according to claim 1, wherein one or more of Sn or Sb or a compound thereof is added to the annealing separator. 3. Manufacture of a mirror-oriented silicon steel sheet having good magnetic properties according to claim 1 or 2, characterized in that Sn or Sb is added as an element in the steel in an amount of 0.03 to 0.15% by mass. Method. 4. The specular directional electromagnetic field with good magnetic properties according to claim 1, wherein the moisture content of the annealing separator during finish annealing is 1.5% or less. Steel plate manufacturing method. 5. The secondary recrystallization is performed in the temperature range of 1000 to 1100 ° C. in the secondary recrystallization temperature range of 20 ° C./hr or less in the finish annealing step. The method for producing a specular grain-oriented electrical steel sheet having a high magnetic flux density according to any one of 1.