KR102180816B1 - Method for manufacutring a grain oriented electrical steel sheet having low core loss - Google Patents

Abstract

A method of manufacturing an ultra-low iron loss grain-oriented electrical steel sheet is provided.
In the grain-oriented electrical steel sheet manufacturing method comprising the steps of reheating the steel slab, hot rolling, hot-rolled sheet annealing, cold rolling, primary recrystallization annealing, and secondary recrystallization annealing, the method for manufacturing a grain-oriented electrical steel sheet of the present invention comprises: A ceramic layer is formed by spraying ceramic powder on one or both sides of a steel sheet subjected to recrystallization annealing treatment, and then secondary recrystallization annealing is performed.

Description

Method for manufacutring a grain oriented electrical steel sheet having low core loss}

The present invention relates to a method for manufacturing a grain-oriented electrical steel sheet.

In general, grain-oriented electrical steel sheet contains 3.1% Si component in the steel sheet, and has an aggregate structure in which the orientation of crystal grains is aligned in the {100}<001>[0002] direction, so it has extremely excellent magnetic properties in the rolling direction. It refers to an electrical steel plate with It is possible to obtain such a {100}<001> texture by a combination of several manufacturing processes. In particular, the components of the steel slab are heated, hot-rolled, hot-rolled sheet annealing, primary recrystallization annealing, and final annealing. The process must be very tightly controlled. Specifically, the grain-oriented electrical steel sheet suppresses the growth of primary recrystallized grains and exhibits excellent magnetic properties due to the secondary recrystallized structure obtained by selectively growing grains of {100}<001> orientation among grains in which growth is suppressed. Therefore, it is more important to inhibit the growth of primary recrystallized grains. And in the final annealing process, one of the main matters in the grain-oriented electrical steel sheet manufacturing technology is to allow the grains having a stable {100}<001> orientation to grow preferentially among grains whose growth is suppressed. Examples of primary crystal grain growth inhibitors that can satisfy the above-described conditions and are widely used industrially include MnS, AlN, and MnSe. Specifically, MnS, AlN, and MnSe contained in the steel slab are reheated at high temperature for a long time to solidify and then hot-rolled, and in the subsequent cooling process, the component having an appropriate size and distribution is made into a precipitate and used as the growth inhibitor. It can be. However, this has a problem in that the steel slab must be heated to a high temperature. In this regard, in recent years, efforts have been made to improve the magnetic properties of grain-oriented electrical steel sheets by heating steel slabs at low temperatures. To this end, a method of adding an antimony (Sb) element to a grain-oriented electrical steel sheet was proposed, but a problem was pointed out that the noise quality of the transformer is inferior due to the uneven and coarse grain size after the final high-temperature annealing.

On the other hand, in order to minimize the power loss of the grain-oriented electrical steel sheet, it is common to form an insulating film on its surface. In this case, the insulating film is basically high in electrical insulation and has excellent adhesion to the material, and has a uniform appearance without defects. It should have one color. In addition, due to the recent reinforcement of international standards for transformer noise and intensifying competition in related industries, research on magnetostriction (magnetism) phenomenon is required in order to reduce the noise of the insulating film of the grain-oriented electrical steel sheet. Specifically, when a magnetic field is applied to an electrical steel sheet used as a transformer core, a vibration phenomenon is caused by repeating contraction and expansion, and vibration and noise are caused in the transformer due to such vibration. In the case of a generally known grain-oriented electrical steel sheet, an insulating film is formed on the steel sheet and the Forsterite base film, and tensile stress is applied to the steel sheet by using the difference in the thermal expansion coefficient of the insulating film to improve iron loss and self-deformation. Although it aims to reduce the noise due to this, there is a limit to satisfying the noise level in the high-grade grain-oriented electrical steel sheet that is recently required. Meanwhile, a wet coating method is known as a method of reducing the 90° magnetic domain of a grain-oriented electrical steel sheet. Here, the 90° magnetic domain refers to a region having magnetization directed at a right angle with respect to the magnetic field application direction, and the smaller the amount of the 90° magnetic domain, the smaller the magnetic deformation. However, the general wet coating method lacks the effect of improving noise due to the application of tensile stress, and has the disadvantage of having to be coated with a thick film having a thick coating thickness, and thus there is a problem that the transformer drop ratio and efficiency are deteriorated.

In addition, a coating method through vacuum deposition such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) is known as a method of imparting high tensile properties to the surface of a grain-oriented electrical steel sheet. However, this coating method is difficult to commercially produce, and the grain-oriented electrical steel sheet manufactured by this method has a problem in that the insulating properties are poor.

The present invention is a dry ceramic that can improve iron loss by 10% or more through a method of melting and spraying ceramic powder with high temperature heat at normal pressure, unlike conventional insulating coating by roll coating to improve the iron loss of 3%. It is an object of the present invention to provide a method for manufacturing a low iron loss grain-oriented electrical steel sheet using a coating process.

In addition, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. Can be.

A method of manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention,

In the grain-oriented electrical steel sheet manufacturing method comprising the step of reheating the steel slab, hot rolling, hot rolled sheet annealing, cold rolling, primary recrystallization annealing, and secondary recrystallization annealing,

It relates to a method for manufacturing a grain-oriented electrical steel sheet in which a ceramic layer is formed by spraying ceramic powder on one or both surfaces of the steel sheet subjected to the primary recrystallization annealing treatment, and then secondary recrystallization annealing.

In addition, the present invention,

Preparing a steel sheet for manufacturing a grain-oriented electrical steel sheet subjected to primary recrystallization annealing treatment;

Forming a ceramic layer by spraying ceramic powder on a part or all of one or both sides of the steel sheet; And

It relates to a grain-oriented electrical steel sheet manufacturing method comprising; secondary recrystallization annealing the steel sheet on which the ceramic layer is formed.

The ceramic layer may be formed by supplying ceramic powder to a heat source obtained by plasmaizing a gas containing Ar, H ₂ , N ₂ , or He at an output of 20 to 300 kW and spraying it on the steel sheet subjected to the primary recrystallization annealing. .

The ceramic powder contains at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Sn and Ba It may be an oxide, nitride, carbide or oxynitride.

The ceramic powder is Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO·Al ₂ O ₃ , 2MgO·SiO ₂ , MgO·SiO ₂ , 2MgO·TiO ₂ , MgO·TiO ₂ , MgO·2TiO ₂ , _{Al 2 O 3 · SiO 2,} 3Al 2 O 3 · 2SiO 2, Al 2 O 3 · TiO 2, ZnO · SiO 2, ZrO 2 · SiO 2, ZrO 2 · TiO 2, 9Al 2 O 3 · 2B 2 O 3 , 2Al ₂ O ₃ ·B ₂ O ₃ , 2MgO·2Al ₂ O ₃ ·5SiO ₂ , Li ₂ O·Al ₂ O ₃ · SiO ₂ , Li ₂ O·Al ₂ O ₃ ·4SiO ₂ , BaO·Al ₂ O _{3 · SiO 2, AlN, SiC} , TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4, FeTiO 4, SrZrO _It may be at least one selected from ₃ , Y ₂ O ₃ and ZrSiO ₄ .

The ceramic layer may have a thickness of 0.1 to 10 μm.

The process of primary recrystallization annealing may be a process of obtaining a decarburized annealed steel sheet by quenching the steel sheet at the same time as decarburization, or by quenching and annealing after decarburization.

The secondary recrystallization annealing process may be a high-temperature annealing process in which the steel sheet on which the ceramic layer is formed is heated in two stages and then subjected to cracking treatment.

After the secondary recrystallization annealing process, a process of forming an insulating film on the surface of the grain-oriented electrical steel sheet on which the ceramic layer is formed may be further included.

The steel sheet is a weight percent, silicon (Si): 2.6 to 4.5%, aluminum (Al): 0.020 to 0.040%, manganese (Mn): 0.01 to 0.20%, the balance may be composed of Fe and other inevitable impurities. have.

According to the present invention having the above-described configuration, instead of applying an annealing separator to the surface of the steel sheet in the primary recrystallization annealing process, a ceramic layer is formed to act as an annealing separator, thereby causing the primary cracking in the subsequent secondary recrystallization process. The process can be omitted and productivity can be improved.

In addition, the ceramic layer of the present invention is a high-tensile coating layer, and unlike a conventional MgO annealing separator, it does not need to be removed, and a grain-oriented electrical steel sheet having excellent iron loss due to high-tension strength can be effectively provided.

1 is a diagram showing a typical grain-oriented electrical steel sheet manufacturing process.
Figure 2 is a diagram showing the manufacturing process of the grain-oriented electrical steel sheet of the present invention.
Figure 3 (ab) is a graph showing the annealing heat treatment process in the secondary recrystallization annealing process, (a) shows a conventional example and (b) shows an example of the present invention.
Figure 4 is a schematic diagram showing the alignment of the high-temperature ceramic melt spraying device of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

1 is a diagram showing a typical grain-oriented electrical steel sheet manufacturing process.

As shown in Fig. 1, first, as an annealing & pickling line (APL), it removes the scale of the hot plate, secures the cold rolling property, and performs the role of depositing and dispersing the inhibitor (AlN) of the hot rolled plate in favor of magnetism. do. Subsequently, the cold rolling process (SendZimir Rolling Mill) performs rolling to the final product thickness required by the customer, and plays a role in securing a crystal orientation that is advantageous for magnetism. In addition, the [C] of the material is removed by a decarburizing & nitriding line (DNL), which is the first recrystallization annealing process, and the primary recrystallization is formed through a nitriding reaction with an appropriate temperature. Subsequently, a base coating (Mg ₂ SiO ₄ ) layer is formed by a high temperature annealing process (COF), which is a second recrystallization annealing process, and a secondary recrystallization is formed. Finally, the shape of the material is corrected by the HCL process, the annealing separator is removed, and then an insulating film is formed to impart tension to the surface of the electrical steel sheet.

In this case, in the prior art, a process of applying an annealing separator MgO after decarburization treatment in the first recrystallization process is performed. Accordingly, in the secondary recrystallization annealing process, the primary cracking treatment is performed after the primary heating, followed by the secondary heating and the secondary cracking treatment.

On the other hand, Figure 2 is a diagram showing the manufacturing process of the grain-oriented electrical steel sheet of the present invention.

As shown in FIG. 2, the present invention forms a ceramic layer using a method of melting and spraying ceramic powder with high temperature heat at normal pressure instead of applying an annealing separator to a steel sheet in a primary recrystallization annealing process. Then, according to the formation of the ceramic layer, a second step of heating is performed in a subsequent secondary recrystallization annealing process, followed by a first crack treatment.

3(a-b) is a graph showing an annealing heat treatment process in a secondary recrystallization annealing process, where (a) shows a conventional example and (b) shows an example of the present invention. As shown in FIG. 3, it can be seen that in the present invention, unlike the prior art, the first crack treatment process can be omitted, and thus productivity can be improved. Furthermore, in the present invention, unlike the prior art, there is also an advantage in that there is no need to remove the annealing separator in the HCL process described above.

As before, the grain-oriented electrical steel sheet manufacturing process of the present invention is substantially the same as in the prior art in the processes prior to the primary recrystallization annealing process.

That is, the present invention uses a general process of reheating, hot rolling, hot-rolled sheet annealing, cold rolling, primary recrystallization annealing, and secondary recrystallization annealing, similar to the prior art, in manufacturing grain-oriented electrical steel sheets. Here, the step of the primary recrystallization annealing may be a step of acquiring a decarburization annealed steel sheet by quenching the steel sheet at the same time as decarburization, or by immersing and annealing the steel sheet after decarburization.

However, unlike the prior art, a ceramic layer is formed using a method of melting and spraying ceramic powder with high temperature heat at normal pressure, instead of an annealing separator, on one or both sides of the steel sheet subjected to the primary recrystallization annealing treatment. do.

In the secondary recrystallization annealing process, a high-temperature annealing process in which the steel sheet on which the ceramic layer is formed is heated in two stages and then cracked once and then cooled by furnace is used.

First, in the present invention, a cold-rolled steel sheet for manufacturing a grain-oriented electrical steel sheet subjected to primary recrystallization annealing is prepared.

In the present invention, the steel sheet is in wt%, silicon (Si): 2.6 to 4.5%, aluminum (Al): 0.020 to 0.040%, manganese (Mn): 0.01 to 0.20%, the balance including Fe and other inevitable impurities Can be done. Hereinafter, the reasons for limiting the composition and content of the steel sheet will be described in the present invention.

Si: 2.6 to 4.5% by weight

Silicon (Si) plays a role in reducing the iron loss by increasing the specific resistance of the steel.If the content of Si is too small, the specific resistance of the steel decreases and the iron loss characteristics deteriorate. Problems can arise. If the content of Si is too large, brittleness may increase, and thus cold rolling may become difficult. Therefore, it is possible to adjust the content of Si in the above-described range. More specifically, Si may be included in 2.6 to 4.5% by weight.

Al: 0.020 to 0.040% by weight

Aluminum (Al) is a component that acts as an inhibitor as it finally becomes nitride in the form of AlN, (Al,Si)N, and (Al,Si,Mn)N. When the Al content is too small, it is difficult to expect a sufficient effect as an inhibitor. In addition, when the Al content is too large, the Al-based nitride precipitates and grows too coarse, so that the effect as an inhibitor may be insufficient. Therefore, it is possible to adjust the content of Al in the above-described range.

Mn: 0.01 to 0.20% by weight

Mn has the same effect of increasing the specific resistance as Si to reduce iron loss, and it reacts with nitrogen introduced by nitriding with Si to form (Al,Si,Mn)N precipitates to grow primary recrystallized grains. It is an important element to suppress secondary recrystallization. However, if the content of Mn is too high, the austenite phase transformation is promoted during hot rolling, and thus the size of the primary recrystallized grains is reduced, thereby making the secondary recrystallization unstable. In addition, when the content of Mn is too low, the austenite-forming element increases the austenite fraction when hot-rolled and reheats to increase the high capacity of the precipitates. It can happen insufficiently. Therefore, it is possible to adjust the content of Mn in the above-described range.

Subsequently, in the present invention, a ceramic layer is formed on a part or all of one or both surfaces of the steel sheet subjected to the primary recrystallization annealing treatment by melting and spraying the ceramic powder with high temperature heat at normal pressure.

That is, in the present invention, as an embodiment, the ceramic layer is supplied with ceramic powder to a heat source in which a gas containing Ar, H ₂ , N ₂ , or He is plasmaized with an output of 20 to 300 kW, and the primary recrystallization annealing It can be formed by spraying on the treated steel sheet.

In addition, the ceramic powder contains at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Sn, and Ba. It may be an oxide, nitride, carbide or oxynitride containing.

More preferably, the ceramic powder is Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO·Al ₂ O ₃ , 2MgO·SiO ₂ , MgO·SiO ₂ , 2MgO·TiO ₂ , MgO·TiO ₂ , MgO·2TiO ₂ , Al ₂ O ₃ SiO ₂ , 3Al ₂ O ₃ 2SiO ₂ , Al ₂ O ₃ TiO ₂ , ZnO SiO ₂ , ZrO ₂ SiO ₂ , ZrO ₂ TiO ₂ , 9Al ₂ O ₃ ·2B ₂ O ₃ , 2Al ₂ O ₃ ·B ₂ O ₃ , 2MgO·2Al ₂ O ₃ ·5SiO ₂ , Li ₂ O·Al ₂ O ₃ · SiO ₂ , Li ₂ O·Al ₂ O ₃ ·4SiO ₂ , _{BaO · Al 2 O 3 · SiO} 2, AlN, SiC, TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4 , FeTiO ₄ , SrZrO ₃ , Y ₂ O ₃ and ZrSiO _{4 It} may be at least one selected from.

In the present invention, the particle diameter of the ceramic powder may be 0.01 to 100 μm. If the particle diameter of the ceramic powder is too small, it may not be accelerated at a sufficient speed during the thermal spray coating process, so that many defects such as pores and cracks are formed in the ceramic layer, and adhesion may be lowered. If the particle diameter of the ceramic powder is too large, there is a problem in that the thickness of the ceramic layer becomes thick and the surface roughness increases. More specifically, the particle diameter of the ceramic powder may be 0.1 to 5 μm.

In addition, in the present invention, it is preferable to limit the thickness of the ceramic layer to a range of 0.1 to 10 μm. If the thickness of the ceramic layer is too thin, the amount of tension generated on the surface of the grain-oriented electrical steel sheet by the ceramic layer is small, so that the effect of reducing iron loss is not large, and the problem that the insulation effect is small may occur. On the other hand, if the thickness of the ceramic layer is too thick, the adhesion of the ceramic layer is lowered, and peeling may occur.

More preferably, the thickness of the ceramic layer is limited to a range of 1 to 3 μm.

On the other hand, a device for melting and spraying ceramics at a high temperature is not easy to cover a large area, but it is possible to cover a wide width of a steel sheet by aligning each spray device as shown in FIG. 4. The number and incidence angles of spray devices positioned on the left and right sides of the steel plate may be determined according to the width of the steel plate or a desired coating thickness.

In the present invention, in the second recrystallization annealing process, the steel sheet on which the ceramic layer is formed is heated in two stages and then subjected to a high-temperature annealing process in which a single cracking treatment is performed. This is technically significant in that it is possible to omit the first cracking treatment compared to the prior art of performing the first and second cracking treatment.

Thereafter, in the present invention, after correcting the shape of the steel sheet in the HCL process, a process of forming an insulating film on the surface on which the ceramic layer is formed may be further included.

That is, an insulating coating layer including metal phosphate may be further formed on the ceramic layer. By further forming an insulating coating layer, insulating properties can be improved.

The metal phosphate may include at least one selected from Mg, Ca, Ba, Sr, Zn, Al, and Mn.

The metal phosphate may be formed of a compound by a chemical reaction of a metal hydroxide and phosphoric acid (H3PO4).

Metal phosphate is composed of a chemical reaction of a metal hydroxide and phosphoric acid (H3PO4), and the metal hydroxide is Sr(OH)2, Al(OH)3, Mg(OH)2, Zn(OH)2, and It may be at least one or more selected from the group containing Ca(OH)2.

As described above, in the case of high-temperature annealing through the decarburization (DNL) process in which the MgO coating process of the present invention is omitted, MgO·H ₂ O is coated to prevent sticking between materials during high-temperature annealing and Mg ₂ SiO ₄ Unlike the prior art, which forms the base coating layer of, by coating a ceramic layer, sticking during high temperature annealing can be prevented and magnetic enhancement can be achieved together. In addition, the MgO coating before high-temperature annealing and the MgO removal process after high-temperature annealing can be eliminated, and the insulating coating process after high-temperature annealing can be deleted depending on the condition of the ceramic layer. Furthermore, depending on the utilization of the ceramic coating process, it is possible to maintain the MgO coating and removal process of the existing process and to replace the insulation coating in the final process, HCL, or perform ceramic coating before insulation coating.

In addition, by removing the MgO process through the high-temperature ceramic coating process, the primary crack section to remove moisture from the MgO coated with MgO·H ₂ O hydrate before forming the existing base coating of Mg ₂ SiO ₄ is deleted. I can. Therefore, when moisture escapes, it is possible to fundamentally remove oxidative defects that have occurred a lot in the outer winding part, upper part, and lower part of the coil due to the temperature difference in the coil. In addition, by deleting the first crack section, the productivity of the existing high-temperature annealing process can be reduced by at least 10 hours, and thus, a dramatic effect on productivity can be seen.

Hereinafter, the present invention will be described in detail through examples.

(Example)

3.4% by weight of silicon (Si), 0.03% by weight of aluminum (Al), 0.15% by weight of manganese (Mn), 0.05% by weight of antimony (Sb), 0.06% by weight of tin (Sn), 0.03 of nickel (Ni) Including wt%, the balance was prepared steel slab consisting of Fe and other inevitable impurities.

Then, the steel slab was heated at 1150° C. for 220 minutes and then hot-rolled to a thickness of 2.3 mm, thereby manufacturing a hot-rolled sheet. Then, the hot-rolled sheet was heated to 1120°C, maintained at 920°C for 95 seconds, quenched in water, pickled, and then cold-rolled to a thickness of 0.23mm to prepare cold-rolled sheets.

After the cold-rolled sheets were put into a furnace maintained at 850°C, the dew point temperature and the oxidation ability were adjusted, and the primary recrystallization annealing was carried out at the same time in the atmosphere of a mixture of hydrogen, nitrogen, and ammonia. , Decarburization annealed steel sheets were prepared.

Thereafter, as ceramic powder, Al ₂ O ₃ was used as a ceramic powder to a heat source formed by plasmaizing argon (Ar) gas at an output of 200 kW without applying an annealing separator on the surfaces of the steel sheets prepared as described above. By supplying, ceramic layers having different thicknesses were formed on the surface of the final annealed plate with a 30mm coating width (w) and a 20mm coating gap (d) in the rolling direction.

And the steel sheet on which the ceramic layer was formed was finally annealed. At this time, the cracking temperature at the time of final annealing was 1200°C and 15°C/hr in the temperature range of the heating section. In addition, a mixed gas atmosphere of 50% by volume of nitrogen and 50% by volume of hydrogen was used up to 1200°C, and after reaching 1200°C, the atmosphere was maintained for 15 hours in an atmosphere of 100% by volume of hydrogen, followed by furnace cooling.

The electrical steel sheet having ceramic layers having different thicknesses as described above was evaluated for magnetic properties under conditions of 1.7T and 50Hz, and is shown in Table 1 below. Meanwhile, W17/50 and B8 are usually used as representative values for magnetic properties of electrical steel sheets. W17/50 refers to the power loss that occurs when a magnetic field with a frequency of 50 Hz is magnetized to 1.7 Tesla by alternating current. Here, Tesla is a unit of magnetic flux density which means flux per unit area. B8 represents the magnetic flux density value flowing through the electrical steel sheet when a current amount of 800 A/m is passed through the winding winding around the electrical steel sheet.

division Coating material Coating thickness (㎛) Iron loss (W17/50, W/kg) Magnetic flux density (BB, T) Comparative Example 1 MgO 1.5 1.22 1.89 Comparative Example 2 MgO 3.7 0.96 1.91 Invention Example 1 Al ₂ O ₃ 1.3 0.87 1.92 Inventive Example 2 Al ₂ O ₃ 1.6 0.81 1.93 Invention Example 3 Al ₂ O ₃ 2.8 0.77 1.94 Invention Example 4 Al ₂ O ₃ 5.6 0.79 1.94

As shown in Table 1, compared to Comparative Examples 1 to 2 in which MgO as an annealing separator was applied, Inventive Examples 1-4 in which ceramic layers were formed using ceramic powder showed more excellent iron loss characteristics. have. Meanwhile, Comparative Example 1-2 in Table 1 is a case in which MgO, which is an annealing separator, is applied to the surface of the steel sheet subjected to the primary recrystallization annealing treatment, and other manufacturing conditions are substantially the same as in Example 1-4.

Although the embodiments and invention examples of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (10)

In the grain-oriented electrical steel sheet manufacturing method comprising the step of reheating the steel slab, hot rolling, hot rolled sheet annealing, cold rolling, primary recrystallization annealing, and secondary recrystallization annealing,
A ceramic layer is formed by supplying and spraying ceramic powder on one or both surfaces of the steel sheet subjected to the primary recrystallization annealing by spraying it to a plasma-formed heat source, and is manufactured by secondary recrystallization annealing,
The ceramic powder is an oxide consisting of at least one selected from Li, B, Ca, Sr, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Sn and Ba, A method for manufacturing a grain-oriented electrical steel sheet, characterized in that it is nitride, carbide or oxynitride.
Preparing a steel sheet for manufacturing a grain-oriented electrical steel sheet subjected to primary recrystallization annealing treatment;
Forming a ceramic layer by supplying and spraying ceramic powder to a plasma-generated heat source on some or all of one or both sides of the steel sheet; And
Including; secondary recrystallization annealing the steel sheet on which the ceramic layer is formed;
The ceramic powder is an oxide consisting of at least one selected from Li, B, Ca, Sr, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Sn and Ba, A method for manufacturing a grain-oriented electrical steel sheet, characterized in that it is nitride, carbide or oxynitride.
The first recrystallization annealing according to claim 1 or 2, wherein the ceramic layer supplies ceramic powder to a heat source obtained by plasmaizing a gas containing Ar, H ₂ , N ₂ , or He at an output of 20 to 300 kW. A method for manufacturing a grain-oriented electrical steel sheet, characterized in that formed by spraying the treated steel sheet.
delete The method of claim 1 or 2, wherein the ceramic powder is Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ SiO ₂ , 3Al ₂ O ₃ 2SiO ₂ , Al ₂ O ₃ TiO ₂ , ZnO·SiO ₂ , ZrO ₂ ·SiO ₂ , ZrO ₂ ·TiO ₂ , 9Al ₂ O ₃ ·2B ₂ O ₃ , 2Al ₂ O ₃ ·B ₂ O ₃ , Li ₂ O·Al ₂ O ₃ · SiO _{2 , Li 2 O · Al 2 O} 3 · 4SiO 2, BaO · Al 2 O 3 · SiO 2, AlN, SiC, TiC, TiN, BN, ZrN, BaTiO 3, SrTiO 3, FeTiO 3, CaO, FeAl 2 O 4 , CaTiO ₃ , FeTiO ₄ , SrZrO ₃ , and ZrSiO _{4 A} method of manufacturing a grain-oriented electrical steel sheet, characterized in that at least one selected from.
The method of claim 1 or 2, wherein the ceramic layer has a thickness of 0.1 to 10 μm.
The grain-oriented electrical steel sheet according to claim 1 or 2, wherein the primary recrystallization annealing step is a step of obtaining a decarburization annealed steel sheet by quenching the steel sheet at the same time as decarburization, or by quenching and annealing the steel sheet after decarburization. Manufacturing method.
The method according to claim 1 or 2, wherein the secondary recrystallization annealing process is a high-temperature annealing process in which the steel sheet on which the ceramic layer is formed is heated in two stages and then subjected to a cracking treatment.
The method for manufacturing a grain-oriented electrical steel sheet according to claim 1 or 2, further comprising a step of forming an insulating film on the surface of the grain-oriented electrical steel sheet on which the ceramic layer is formed after the secondary recrystallization annealing step.
The method of claim 1 or 2, wherein the steel sheet is in wt%, silicon (Si): 2.6 to 4.5%, aluminum (Al): 0.020 to 0.040%, manganese (Mn): 0.01 to 0.20%, the balance is Fe And grain-oriented electrical steel sheet manufacturing method, characterized in that it comprises other inevitable impurities.

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