JP6808830B2 - Electrical steel sheet and its manufacturing method - Google Patents

Description

The present invention relates to a grain-oriented electrical steel sheet and a method for producing the same, and more particularly to a grain-oriented electrical steel sheet obtained by containing a certain amount of B, Ba, and Y and segregating at grain boundaries and a method for producing the same.

The grain-oriented electrical steel sheet is a soft magnetic material having excellent magnetic properties in the rolling direction, which is composed of crystal grains having a crystal orientation of {110} <001>, also known as a Goss orientation.
Generally, the magnetic characteristics are expressed by the magnetic flux density and the iron loss, and the high magnetic flux density is obtained by accurately arranging the orientations of the crystal grains in the {110} <001> orientation. An electromagnetic steel sheet having a high magnetic flux density can not only reduce the size of the iron core material of an electric device, but also reduce the history loss, so that the electric device can be miniaturized and the efficiency can be improved at the same time. Iron loss is the power loss consumed as thermal energy when an arbitrary alternating magnetic field is applied to a steel plate, and is the magnetic flux density and thickness of the steel plate, the amount of impurities in the steel plate, the specific resistance, and the secondary recrystallization. It varies greatly depending on the grain size and the like, and the higher the magnetic flux density and specific resistance, and the lower the plate thickness and the amount of impurities in the steel plate, the lower the iron loss and the higher the efficiency of electrical equipment.

Currently, in order to deal with global warming by reducing CO ₂ emissions worldwide, there is a tendency to aim for high-efficiency products as well as energy saving, and highly efficient electrical equipment that uses less electrical energy. As the demand for expansion and dissemination increases, the social demand for the development of grain-oriented electrical steel sheets having better low iron loss characteristics is increasing.
Generally, in a directional electromagnetic steel sheet having excellent magnetic properties, a Goss texture in the {110} <001> direction must be strongly developed in the rolling direction of the steel sheet, and in order to form such an aggregate structure. In order, the grains in the Goth orientation must form an abnormal grain growth called secondary recrystallization. Such abnormal crystal growth is different from normal grain growth, and the movement of grain boundaries in which normal grain growth normally grows due to precipitates, inclusions, or elements that segregate into solid solutions or grain boundaries. Occurs when is suppressed. Precipitates and inclusions that suppress grain growth in this way are particularly called grain growth inhibitors (inhibitors), and research on manufacturing technology for directional electromagnetic steel sheets by secondary recrystallization in the {110} <001> orientation. Has focused its efforts on forming secondary recrystallization with a high degree of integration with respect to the {110} <001> orientation using a strong grain growth inhibitor to ensure excellent magnetic properties.

In the existing grain-oriented electrical steel sheet technology, precipitates such as AlN and MnS [Se] are mainly used as a crystal grain growth inhibitor. As an example, after one strong cold rolling and decarburization, nitrogen is supplied to the inside of the steel sheet by a separate nitriding process using ammonia gas to exert a strong grain growth suppressing effect. There is a manufacturing method in which secondary recrystallization is caused by the nitride of the above.
However, the complexity of the manufacturing process is that the instability of the precipitate due to denitrification or renitrification due to the atmosphere in the furnace becomes serious in the high temperature annealing process, and that long-term purification annealing at high temperature for 30 hours or more is required. And cost burden.

For this reason, recently, a method for producing grain-oriented electrical steel sheets without using precipitates such as AlN and MnS as a crystal grain growth inhibitor has been proposed. As an example, there is a production method using grain boundary segregation elements such as barium (Ba) and yttrium (Y).
Ba and Y are excellent in the effect of suppressing grain growth so that secondary recrystallization can be formed, and have advantages such as not being affected by the atmosphere in the furnace during the high temperature annealing process, but they are said to weaken the binding force of the grain boundaries. There are drawbacks. Therefore, there is a problem that a large number of grain boundary cracks are generated in the cold rolling process that requires strong reduction, and a decrease in productivity cannot be avoided.

An object of the present invention is to provide a grain-oriented electrical steel sheet and a method for producing the same.

The grain-oriented electrical steel sheet according to an embodiment of the present invention contains Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y alone or in total in% by weight. It is characterized by containing 0.005% by weight to 0.5% by weight, and the balance containing Fe and other unavoidable impurities.

The grain-oriented electrical steel sheet according to an embodiment of the present invention can satisfy the following formula 1.
[Equation 1]
0.5 ≤ ([Ba] + [Y]) / ([B] * 10) ≤ 3
(However, in Formula 1, [Ba], [Y], and [B] indicate the contents (% by weight) of Ba, Y, and B, respectively.)
C: 0.005% or less (excluding 0%), Al: 0.005% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less (Excluding 0%) can be further included.

Mn: 0.01% to 0.5% can be further contained.
The average particle size of the crystal grains having a particle size of 2 mm or more is preferably 10 mm or more.
B segregated at the grain boundaries and Ba or Y can be included.

In the method for producing a directional electromagnetic steel sheet according to an embodiment of the present invention, Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y are used alone or in% by weight, respectively. The total amount contains 0.005% by weight to 0.5% by weight, and the balance is the stage of heating a slab containing Fe and other unavoidable impurities, the stage of hot rolling the slab to produce a hot-rolled plate, and the stage of hot-rolled plate. Includes a step of cold rolling to produce a cold rolled plate, a step of primary recrystallization annealing of the cold rolled plate, and a step of secondary recrystallization annealing of the cold rolled plate for which the primary recrystallization annealing has been completed. Characterized by

The slab can satisfy the following equation 1.
[Equation 1]
0.5 ≤ ([Ba] + [Y]) / ([B] * 10) ≤ 3
(However, in Formula 1, [Ba], [Y], and [B] indicate the contents (% by weight) of Ba, Y, and B, respectively.)
The slab has C: 0.001 to 0.1%, Al: 0.01% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less. (Excluding 0%) can be further included.

The slab can further contain Mn: 0.01% to 0.5%.
At the stage of heating the slab, it is preferable to heat it to 1000 to 1280 ° C.
At the stage of cold-rolling the hot-rolled plate to produce the cold-rolled plate, the final reduction ratio is preferably 80% or more.
The secondary recrystallization annealing step includes a temperature raising step and a heat soaking step, and the temperature of the heat soaking step is preferably 900 to 1250 ° C.

The grain-oriented electrical steel sheet according to an embodiment of the present invention is excellent in magnetic properties by stably forming Goth crystal grains.
Moreover, since AlN and MnS are not used as the crystal grain growth inhibitor, it is not necessary to heat the slab to a high temperature of 1300 ° C. or higher.
Further, due to the effect of strengthening the grain boundaries, the occurrence of grain boundary cracks is reduced even under strong cold rolling, and the productivity is improved and the manufacturing cost is reduced.

It is a photograph of a cold-rolled steel sheet in the manufacturing process of the invention material of sample number 2. It is a photograph of a cold-rolled steel sheet in the manufacturing process of the comparative material of sample number 1.

Terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and / or sections. These terms are used only to distinguish one part, component, area, layer or section from another part, component, area, layer or section. Therefore, the first part, component, region, layer or section described below is referred to as the second part, component, region, layer or section within the scope of the present invention.
The terminology used herein is merely to refer to a particular embodiment and is not intended to limit the invention. The singular form used herein also includes multiple forms, unless the wording has a clear opposite meaning. As used herein, the meaning of "contains" embodies a particular property, region, integer, stage, behavior, element and / or component, and other characteristics, region, integer, stage, behavior, element and / or. It does not exclude the presence or addition of ingredients.

When referring to one part being "above" another part, this may be just above the other part, or with another part in between. In contrast, when one mentions that one part is "directly above" another, there is no other part in between.
Although not defined separately, all terms, including the technical and scientific terms used herein, have the same meaning as generally understood by those with ordinary knowledge in the technical field to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and currently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.
Further, unless otherwise specified,% means% by weight, and 1 ppm is 0.0001% by weight.

Hereinafter, examples of the present invention will be described in detail so that a person having ordinary knowledge in the technical field to which the present invention belongs can easily carry out the examples. However, the present invention is feasible in a variety of different forms and is not limited to the examples described herein.
In the existing directional electromagnetic steel sheet technology, precipitates such as AlN and MnS are used as the crystal grain growth inhibitor, and all the steps strictly control the distribution of the precipitates and secondary recrystallization is performed. The process conditions were extremely limited by the conditions for removing the precipitates remaining in the steel sheet.
On the other hand, in one embodiment of the present invention, precipitates such as AlN and MnS are not used as the crystal grain growth inhibitor. In one embodiment of the present invention, by using B and Ba or Y as a crystal grain growth inhibitor, the fraction of Goss crystal grains can be increased and an electromagnetic steel sheet having excellent magnetism can be obtained.

The grain-oriented electrical steel sheet according to an embodiment of the present invention is Si: 1.0 to 7.0%, Mn: 0.01% to 0.5%, B: 0.001 to 0.1% in weight%. In addition, Ba and Y are contained alone or in a combined amount of 0.005% by weight to 0.5% by weight, and the balance contains Fe and other unavoidable impurities.
Hereinafter, each component will be specifically described.

In one embodiment of the present invention, barium (Ba) and yttrium (Y) act as crystal grain growth inhibitors, and during secondary recrystallization annealing, crystal grains in directions other than Goth crystal grains grow. To improve the magnetism of the electromagnetic steel sheet. Ba and Y may be added individually or in combination. Ba and Y can be contained alone or in a combined amount of 0.005% by weight to 0.5% by weight, respectively. That is, when Ba or Y is added alone, the content of Ba or Y may be 0.005% by weight to 0.5% by weight, respectively, and when Ba and Y are added at the same time, Ba. And the total content of Y may be between 0.005% and 0.5% by weight (ie, the total amount). If the amount of Ba or Y or the total amount thereof is too small, it is difficult to exert a sufficient restraining force, and if the amount of Ba or Y or the total amount thereof is too large, the brittleness of the steel sheet increases and cracks may occur during rolling. ..

Boron (B, boron) segregates at the grain boundaries and strengthens the grain boundary bonding force, so that it plays a role of reducing crack generation during rolling and the number of rolling times. In addition, it reacts with nitrogen in steel to form a part of BN precipitate, but BN is excellent in high temperature stability and can act as an auxiliary inhibitor that suppresses crystal grain growth together with Ba and Y described above. is there. The content of B may be 0.001 to 0.1% by weight. If B is contained in an excessively small amount, it may be insufficient to alleviate the intergranular brittleness due to Ba and Y. If B is contained in an excessively large amount, the grain boundary segregation of Ba and Y can be suppressed, and a large number of inclusions can be formed in the high temperature annealing process to deteriorate the magnetic properties.
B can satisfy the following equation 1 in relation to Ba and Y.
[Equation 1]
0.5 ≤ ([Ba] + [Y]) / ([B] * 10) ≤ 3
(However, in Formula 1, [Ba], [Y], and [B] indicate the contents (% by weight) of Ba, Y, and B, respectively.)
When the value of Equation 1 is less than 0.5, the grain boundary segregation of Ba and Y can be suppressed, and a large number of inclusions can be formed in the high temperature annealing process to deteriorate the magnetic properties. If the value of Equation 1 exceeds 3, it may be insufficient to alleviate the intergranular brittleness due to Ba and Y.

Silicon (Si) plays a role of increasing the specific resistance of the material and lowering the iron loss. If the Si content of the slab and the electrical steel sheet is less than 1.0% by weight, the specific resistance may decrease and the iron loss characteristics may decrease. On the contrary, when the Si content of the grain-oriented electrical steel sheet exceeds 7% by weight, it is difficult to process it at the time of manufacturing the transformer. Therefore, the Si content of the grain-oriented electrical steel sheet is preferably 7% by weight or less.
Carbon (C) is an austenite stabilizing element, which is added to 0.001% by weight or more in the slab to refine the coarse columnar structure generated in the continuous casting process and suppress the segregation of S in the slab center. Can be done. Further, it is possible to promote work hardening of the steel sheet during cold rolling to promote nucleation of secondary recrystallization in the {110} <001> orientation in the steel sheet. However, if it exceeds 0.1%, edge-cracks may occur during hot spreading. However, the electrical steel sheet undergoes decarburization annealing during production, and the C content in the final electrical steel sheet after decarburization annealing is preferably 0.005% by weight or less. More specifically, it is 0.003% by weight or less.

In one embodiment of the present invention, since precipitates such as AlN and MnS are not used as a grain growth inhibitor, they are essential for general directional electromagnetic steel sheets such as aluminum (Al), nitrogen (N) and sulfur (S). The elements used as are controlled in the impurity range. That is, when Al, N, S and the like are inevitably further contained, Al may be further contained in 0.005% by weight or less, S in 0.0055% by weight or less, and N in 0.0055% by weight or less.
In one embodiment of the present invention, since AlN does not have to be used as a crystal grain growth inhibitor, the aluminum (Al) content can be positively suppressed. Therefore, in one embodiment of the present invention, Al is not added to the grain-oriented electrical steel sheet, or it can be controlled to 0.005% by weight or less. Further, in the slab, since Al is removed in the manufacturing process, Al can be contained in an amount of 0.01% by weight or less.

Nitrogen (N) forms precipitates such as AlN, (Al, Mn) N, (Al, Si, Mn) N, Si3N4, and BN. Therefore, in one embodiment of the present invention, N is not added. , 0.0055% by weight or less can be controlled. More specifically, it may be 0.0030% by weight or less. In one embodiment of the present invention, since the nitrification step can be omitted, the N content in the slab and the N content in the final magnetic steel sheet can be substantially the same.
Sulfur (S) is an element that has a high solid solution temperature and severe segregation during hot rolling. Therefore, in one embodiment of the present invention, sulfur (S) may not be added or may be controlled to 0.0055% by weight or less. .. More specifically, it may be 0.0035% by weight or less.

In one embodiment of the present invention, since MnS is not used as a crystal grain growth inhibitor, manganese (Mn) does not have to be added. However, since Mn is a resistivity element and has an effect of improving magnetism, it may be additionally contained as an optional component in the slab and the electromagnetic steel sheet. When Mn is additionally contained, the content of Mn may be 0.01% by weight or more. However, if it exceeds 0.5% by weight, phase transformation may occur after secondary recrystallization and the magnetism may deteriorate. In one embodiment of the present invention, it is understood that when additional elements are further included, the remaining iron (Fe) is added in place of it.
In addition, as other unavoidable impurities, components such as Ti, Mg, and Ca react with oxygen in steel to form oxides, which interfere with the movement of magnetic domains in the final product as inclusions and cause magnetic deterioration. Since it can be a cause, it is necessary to strongly suppress it. Therefore, when these are unavoidably contained, each component can be controlled at 0.005% by weight or less.

In the grain-oriented electrical steel sheet according to an embodiment of the present invention, the average particle size of crystal grains having a particle size of 2 mm or more is 10 mm or more. When the average particle size of the crystal grains having a particle size of 2 mm or more is less than 10 mm, the crystal grains do not grow sufficiently and the magnetism may decrease. In one embodiment of the present invention, the grain size of the crystal grains means the length of the diameter with respect to the crystal grains corresponding to the circle.
The grain-oriented electrical steel sheet according to an embodiment of the present invention is excellent in magnetic properties by stably forming Goth crystal grains. Specifically, the grain-oriented electrical steel sheet according to the embodiment of the present invention may have a magnetic flux density of B8 of 1.88 T or more measured in a magnetic field of 800 A / m.

In the method for producing a directional electromagnetic steel sheet according to an embodiment of the present invention, Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y are used alone or in% by weight, respectively. The total amount contains 0.005% by weight to 0.5% by weight, and the balance is the stage of heating the slab containing Fe and other unavoidable impurities, the stage of hot rolling the slab to produce a hot-rolled plate, and the hot-rolled plate. Includes a step of cold rolling to produce a cold rolled plate, a step of primary recrystallization annealing of the cold rolled plate, and a step of secondary recrystallization annealing of the cold rolled plate for which the primary recrystallization annealing has been completed. ..

Hereinafter, the method for manufacturing the grain-oriented electrical steel sheet will be specifically described for each step.
First, the slab is heated.
Since the composition of the slab has been specifically described in relation to the composition of the electrical steel sheet, duplicate description will be omitted.
The heating temperature of the slab is not limited, but heating the slab to a temperature of 1280 ° C or lower prevents the columnar crystal structure of the slab from growing coarsely and prevents cracks in the plate during the hot rolling process. can do. Therefore, the heating temperature of the slab may be 1000 ° C. to 1280 ° C. In particular, in one embodiment of the present invention, since AlN and MnS are not used as the crystal grain growth inhibitors, it is not necessary to heat the slab to a high temperature of 1300 ° C. or higher.

Next, the slab is hot-rolled to produce a hot-rolled plate. The hot rolling temperature is not limited, and as an example, hot rolling can be completed at 950 ° C. or lower. After that, it can be cooled with water and wound at 600 ° C. or lower.
Next, if necessary, the hot-rolled plate can be annealed. When the hot-rolled plate is annealed, it can be heated to a temperature of 900 ° C. or higher, equalized, and then cooled in order to make the hot-rolled structure uniform.
Next, the hot-rolled plate is cold-rolled to produce a cold-rolled plate. Cold rolling, using a reverse (Reverse) mill or a tandem (Tandem) rolling mill, one of the cold rolling, a plurality of times of cold rolling, or multiple cold rolling method including intermediate annealing 0 A cold rolled plate having a thickness of 1 mm to 0.5 mm can be produced.
In addition, warm rolling can be performed in which the temperature of the steel sheet is maintained at 100 ° C. or higher during cold rolling.

Further, the final rolling reduction by cold rolling may be 80% or more. In one embodiment of the present invention, as described above, by including B in the slab component at a specific content, segregation occurs at the grain boundaries and the grain boundary bonding force is strengthened, so that cracks occur during rolling and the number of times of rolling. Can be reduced and the final rolling reduction rate can be increased.
Next, the cold-rolled cold-rolled sheet is first recrystallized and annealed. Primary recrystallization In the annealing step, primary recrystallization occurs in which nuclei of Goth grains are generated. The cold rolled plate is decarburized at the primary recrystallization annealing stage. For decarburization, it can be annealed at a temperature of 800 ° C to 900 ° C. Further, the atmosphere may be a mixed gas atmosphere of hydrogen and nitrogen. Further, when the decarburization is completed, the carbon content in the cold rolled plate may be 0.005% by weight or less. In one embodiment of the present invention, since the AlN crystal grain growth inhibitor is not used, the nitriding step can be omitted.

Next, the cold-rolled plate for which the primary recrystallization annealing has been completed is subjected to the secondary recrystallization annealing. At this time, after applying the annealing separator to the cold-rolled plate for which the primary recrystallization annealing has been completed, the secondary recrystallization annealing can be performed. At this time, the annealing separator is not particularly limited, and an annealing separator containing MgO as a main component can be used.
The secondary recrystallization annealing step includes a heating step and a soaking step. The temperature raising step is a step of raising the temperature of the cold rolled sheet for which the primary recrystallization annealing has been completed to the temperature of the soaking step. The temperature of the soaking step may be 900 ° C to 1250 ° C. If it is less than 900 ° C., the Goth crystal grains do not grow sufficiently and the magnetism decreases, and if it exceeds 1250 ° C., the crystal grains grow coarsely and the characteristics of the electrical steel sheet may deteriorate. The heating step is performed in a mixed gas atmosphere of hydrogen and nitrogen, and the soaking step is performed in a hydrogen atmosphere.

Since the method for producing grain grain growth inhibitor of AlN and MnS is not used in the method for producing grain grain growth inhibitor according to the embodiment of the present invention, the purification annealing step can be omitted after the secondary recrystallization annealing is completed. In the conventional method for producing grain-oriented electrical steel sheets using MnS and AlN as grain growth inhibitors, high-temperature purification annealing for removing precipitates such as AlN and MnS was required. The method for manufacturing grain-oriented electrical steel sheets according to one embodiment does not require a purification annealing step.
After that, if necessary, an insulating film can be formed on the surface of the grain-oriented electrical steel sheet, or a magnetic domain miniaturization treatment can be performed. In one embodiment of the present invention, the alloy component of the grain-oriented electrical steel sheet means a base steel sheet excluding a coating layer such as an insulating film.
Hereinafter, the present invention will be described in more detail through examples. However, such examples are merely for exemplifying the present invention, and the present invention is not limited thereto.

Example 1
By weight%, it contains Si: 3.2%, C: 0.05%, Mn: 0.06%, S: 0.0048%, N: 0.0032%, and Al: 0.005%. A slab containing barium (Ba), yttrium (Y), and boron (B) as shown in Table 1 below, and consisting of the balance Fe and other unavoidably mixed impurities was prepared.
The slab was heated to a temperature of 1150 ° C. for 90 minutes and then hot-rolled to produce a hot-rolled plate having a thickness of 2.6 mm. The hot-rolled plate was heated to a temperature of 1050 ° C. or higher, maintained at 910 ° C. for 90 seconds, cooled with water, and then pickled. Next, using a Reverse rolling mill, cold rolling was performed to a thickness of 0.30 mm through a total of 7 passes. The reduction rate per pass was applied the same for each test condition. After the temperature of the cold-rolled steel sheet is raised in the furnace, it is maintained at a mixed gas atmosphere of hydrogen: 50% by volume and nitrogen: 50% by volume and an annealing temperature of 850 ° C. for 120 seconds to have a carbon concentration of 0.002% by volume. Primary recrystallization annealing was performed along with decarburization to%. Then, after applying MgO, it was wound into a coil and annealed for secondary recrystallization. In the secondary recrystallization annealing, the temperature is raised to 1200 ° C. in a mixed gas atmosphere of nitrogen: 25% by volume and hydrogen: 75% by volume, and after reaching 1200 ° C., maintained in a gas atmosphere of hydrogen: 100% by volume for 20 hours, and then the furnace. It was chilled.

After surface cleaning of the finally obtained steel sheet, the magnetic flux density was measured under the condition of a magnetic field strength of 800 A / m using a single sheet measurement method.

As can be confirmed from Table 1, when the B content is controlled within the range of the present invention according to the Ba and Y contents, rolling cracks do not occur and the magnetism is superior to that of the comparative material. I was able to get it.
Further, FIGS. 1 and 2 show a photograph of a cold-rolled steel sheet during the manufacturing process of the invention material of Sample No. 2 and a photograph of the cold-rolled steel sheet during the manufacturing process of the comparative material of Sample No. 1. In the case of the comparative material, it can be confirmed that rolling cracks clearly appear.

Example 2
By weight%, it contains Si: 3.2%, C: 0.048%, Mn: 0.11%, S: 0.0051%, N: 0.0028%, and Al: 0.008%. A slab containing barium (Ba), yttrium (Y), and boron (B) as shown in Table 2 below, and consisting of the balance Fe and other unavoidably mixed impurities was prepared.
The slab was heated to a temperature of 1150 ° C. for 90 minutes and then hot-rolled to produce a hot-rolled plate having a thickness of 2.6 mm. The hot-rolled plate was heated to a temperature of 1050 ° C. or higher, maintained at 910 ° C. for 90 seconds, cooled with water, and then pickled. Next, using a Reverse rolling mill, cold rolling was performed to a thickness of 0.30 mm through a total of 7 passes. The reduction rate per pass was applied the same for each test condition. After the temperature of the cold-rolled steel sheet is raised in the furnace, it is maintained at a mixed gas atmosphere of hydrogen: 50% by volume and nitrogen: 50% by volume and an annealing temperature of 850 ° C. for 120 seconds to have a carbon concentration of 0.003% by volume. Primary recrystallization annealing was performed along with decarburization to%. Then, after applying MgO, it was wound into a coil and annealed for secondary recrystallization. In the secondary recrystallization annealing, the temperature is raised to 1200 ° C. in a mixed gas atmosphere of nitrogen: 25% by volume and hydrogen: 75% by volume, and after reaching 1200 ° C., maintained in a gas atmosphere of hydrogen: 100% by volume for 20 hours, and then the furnace. It was chilled.

After surface cleaning of the finally obtained steel sheet, the magnetic flux density was measured under the condition of a magnetic field strength of 800 A / m using a single sheet measurement method. The grain size of the crystal grains was calculated by immersing in hydrochloric acid heated to 60 ° C. for 5 minutes to remove the coating layer on the surface, and then calculating the average value according to the area.
With reference to Table 2, in the electromagnetic steel sheet according to the embodiment of the present invention, the average particle size of the crystal grains having a particle size of 2 mm or more was 10 mm or more, and it was clarified that the magnetic steel sheet was excellent in magnetism.

The present invention is not limited to the above-mentioned examples, and can be produced in various forms different from each other, and a person having ordinary knowledge in the technical field to which the present invention belongs may consider the technical idea of the present invention. You will understand that it can be implemented in other concrete forms without changing the essential features. Therefore, it should be understood that the above-described embodiments are exemplary in all respects and are not limiting.

Claims (9)

By weight%, Si: 1.0 to 7.0%, B: 0.001 to 0.1 %, Ba and Y alone or in total, 0.005% by weight to 0.5% by weight , C: 0.005% or less (excluding 0%) , Al: 0.005% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less (0) % excluding) wherein, the balance being impurities mixed in Fe and other unavoidable, oriented electrical steel sheet satisfies the following formula 1.
[Equation 1]
0.5 ≤ ([Ba] + [Y]) / ([B] * 10) ≤ 3
(However, in Formula 1, [Ba], [Y], and [B] indicate the contents (% by weight) of Ba, Y, and B, respectively.) The grain-oriented electrical steel sheet according to claim 1, further comprising Mn: 0.01% to 0.5%. The grain-oriented electrical steel sheet according to claim 1 or 2, wherein the average particle size of the crystal grains having a particle size of 2 mm or more is 10 mm or more. The grain-oriented electrical steel sheet according to any one of claims 1 to 3 , which contains B segregated at the grain boundaries and Ba or Y. By weight%, Si: 1.0 to 7.0%, B: 0.001 to 0.1 %, Ba and Y alone or in total, 0.005% by weight to 0.5% by weight , C: 0.001 to 0.1%, Al: 0.01% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less (excluding 0%) ) wherein, the balance being impurities mixed in Fe and other unavoidable, satisfies the following formula 1, heating the slab stage;
A stage in which the slab is hot-rolled to produce a hot-rolled plate;
A stage in which the hot-rolled plate is cold-rolled to produce a cold-rolled plate;
The stage of primary recrystallization annealing of the cold rolled plate; and;
A method for producing a grain-oriented electrical steel sheet, which comprises a step of secondary recrystallization annealing of the cold-rolled sheet for which the primary recrystallization annealing has been completed.
[Equation 1]
0.5 ≤ ([Ba] + [Y]) / ([B] * 10) ≤ 3
(However, in Formula 1, [Ba], [Y], and [B] indicate the contents (% by weight) of Ba, Y, and B, respectively.) The method for producing a grain-oriented electrical steel sheet according to claim 5, wherein the slab further contains Mn: 0.01% to 0.5%. The method for manufacturing a grain-oriented electrical steel sheet according to claim 5 or 6, wherein the slab is heated to 1000 to 1280 ° C. at the stage of heating. The direction according to any one of claims 5 to 7 , wherein the final reduction rate is 80% or more at the stage of cold-rolling the hot-rolled sheet to produce the cold-rolled sheet. Manufacturing method of electromagnetic steel sheet. Any one of claims 5 to 8 , wherein the secondary recrystallization annealing step includes a temperature raising step and a heat soaking step, and the temperature of the heat soaking step is 900 to 1250 ° C. The method for manufacturing a directional electromagnetic steel plate according to the section.