JP2018504518A - High silicon steel sheet with excellent magnetic properties and method for producing the same - Google Patents

Abstract

Provided are a high silicon steel plate excellent in magnetic properties and a method for producing the same. According to the present invention, by weight ratio, Si 4-7%, Al 0.1-3%, the sum of Si + Al is 5.5-7.5%, and the molten silicon steel composed of the remainder Fe is nitrogen or A strip casting step of strip casting in an argon atmosphere, a hot rolling step of hot rolling the strip cast strip to produce a high silicon steel plate, and the hot rolled high silicon steel plate with nitrogen, argon Or a heat treatment step in which heat treatment is performed in a non-oxidizing atmosphere of a mixed atmosphere of hydrogen and nitrogen, a warm rolling step in which the heat-treated high silicon steel sheet is warm-rolled to a final thickness of 0.5 mm or less, and the high silicon A final heat treatment step of subjecting the steel plate to a final heat treatment at a temperature of 800 ° C. to 1200 ° C., wherein the final heat treatment step is performed. After, in order to improve the magnetic high-frequency region, comprising forming a soft ferrite layer on the surface of the high silicon steel sheet manufactured in final thickness.

Description

  The present invention relates to a high silicon electrical steel sheet having excellent magnetic properties and a method for producing the same, and more specifically, by applying magnetic iron oxide to a high silicon steel before or after final heat treatment to form a composite structure, The present invention relates to a high silicon steel sheet and a method for producing the same, in which magnetic properties are dramatically improved as compared with ordinary high silicon steel.

  In general, electromagnetic steel sheets containing silicon are used for iron core materials such as transformers, electric motors, generators and other electromagnetic devices. Electrical steel sheets are required to be excellent in magnetic flux density and iron loss. Since the amount of iron core required to achieve the same performance is smaller as the magnetic flux density is larger, the electrical equipment can be downsized.

  The iron loss causing energy loss is composed of eddy current loss and hysteresis loss. As the frequency increases with alternating current, the component of eddy current loss increases. Since eddy current loss is heat generated by eddy current generated when a magnetic field is induced in the iron core, silicon is added for the reduction. When the silicon content is added to 6.5%, the magnetostriction causing noise is reduced to 0, and the magnetic permeability shows the maximum value. Further, when the silicon content is 6.5%, the high frequency characteristics are very good. High value-added electrical equipment such as inverters and reactors used in new renewable energy power generation equipment, generator induction heating equipment for gas turbines, reactors for uninterruptible power supplies, etc., utilizing such excellent magnetic properties of high silicon steel It can be applied to other uses.

  A high silicon steel sheet containing 6.5% Si is excellent in magnetic properties, but when Si becomes 3.5% or more, cold rolling is impossible by a normal method. Therefore, since it is impossible to produce a high silicon steel plate by ordinary hot rolling-cold or warm rolling, an attempt has been made to produce a high silicon steel plate having excellent magnetic properties by another method.

  The technology known as a method for producing a high silicon steel sheet so far includes a direct casting method using a single roll or a twin roll such as Japanese Unexamined Patent Publication No. 56-3625, and Japanese Unexamined Patent Publication No. 5-171281 etc. As described above, a so-called cladding method has been tried in which high silicon steel is placed inside and rolling is performed with low silicon steel placed outside, but these techniques have not yet been commercialized.

  In Korean Patent Publication No. 10-0374292, etc., powder metallurgy is used to make a high silicon steel block made of powder instead of a high silicon steel plate and use it as an alternative to the high silicon steel plate. A pure iron powder core, a high silicon steel powder core, and a sendust powder core are used in combination, but the soft magnetic properties are inferior to those of a high silicon steel plate due to the properties of the powder.

As a technique for mass-producing high silicon steel containing 6.5% Si, chemical vapor deposition (CVD, Chemicla Vapor Deposition) in a way, Japanese Patent Publication for diffusion anneal with SiCl ₄ to 3% Si steel No. 38-26263, Japanese Patent Publication No. 45-21181, and Japanese Unexamined Patent Publication No. 62-227078. These methods have the disadvantage that toxic SiCl ₄ must be used and that diffusion annealing takes a long time.

  In the electromagnetic steel sheet, the brittleness of the silicon steel sheet increases as the silicon content increases, and it is impossible to cold-roll a silicon steel sheet containing 3.5% Si or more of silicon. However, there is an attempt to produce a thin plate laboratory by a so-called warm rolling method that raises the rolling temperature.

  Increasing the rolling temperature has the effect of improving the rollability, but the improvement effect is not sufficient, and there are many difficulties in the process of producing a hot-rolled sheet.

  The present invention provides a high-silicon steel plate with excellent magnetic properties, which is formed by forming a MnZnNi-based soft ferrite layer with excellent high-frequency characteristics on the surface of a high-silicon steel plate, thereby dramatically improving the magnetism in the high-frequency region. A manufacturing method is provided.

According to one embodiment of the present invention, by weight ratio, Si 4-7%, Al 0.1-3%, the sum of Si + Al is 5.5-7.5%, and the silicon steel melt composed of the remainder Fe A strip casting step of strip casting in a nitrogen or argon atmosphere, a hot rolling step of hot rolling the strip cast strip to produce a high silicon steel plate, and the hot rolled high silicon steel plate A heat treatment stage in which heat treatment is performed in a non-oxidizing atmosphere of nitrogen, argon, or a mixed atmosphere of hydrogen and nitrogen, and a warm rolling stage in which the heat-treated high silicon steel sheet is warm-rolled to a final thickness of 0.5 mm or less. In the method for producing a high silicon steel plate, comprising a final heat treatment step of subjecting the high silicon steel plate to a final heat treatment at a temperature of 800 ° C. to 1200 ° C.,
After performing the final heat treatment step, high silicon having excellent magnetic properties including a step of forming a soft ferrite layer on the surface of a high silicon steel plate manufactured to a final thickness in order to improve magnetism in a high frequency region A method for manufacturing a steel sheet is provided.

  The soft ferrite layer is formed on both sides of the surface of a high silicon steel plate manufactured to a final thickness.

  The soft ferrite layer may be made of MnZnNi-based soft ferrite.

  The MnZnNi soft ferrite may be made of Mn oxide, Zn oxide, Ni oxide, or Fe oxide.

  The total thickness of both surfaces of the soft ferrite layer may be 1 μm or more and 30 μm or less.

The soft ferrite layer forming step includes applying a soft ferrite powder to the surface of the high silicon steel plate mixed with a magnetic steel sheet coating solution,
After mixing and applying a soft ferrite powder and a phosphate binder to the surface of the high silicon steel sheet, mixing and applying a magnetic steel sheet coating solution on the soft ferrite powder; and
It may consist of any one of the steps of causing the soft ferrite powder to collide with the steel plate at a high speed in vacuum or at room temperature and attaching it to the surface.

At least one of SiO ₂ , CaO, Nb ₂ O ₅ , V ₂ O ₅ , ZrO ₂ , and MoO ₃ may be added to the soft ferrite layer.

  According to one embodiment of the present invention, a soft ferrite layer is formed on the surface of a high silicon steel sheet manufactured to a final thickness in order to improve magnetism in a high frequency region. An excellent high silicon steel sheet is provided.

  The soft ferrite layer is formed on both sides of the surface of a high silicon steel plate manufactured to a final thickness.

  The soft ferrite layer may be made of MnZnNi-based soft ferrite.

  The MnZnNi soft ferrite may be made of Mn oxide, Zn oxide, Ni oxide, or Fe oxide.

  The total thickness of both surfaces of the soft ferrite layer may be 1 μm or more and 30 μm or less.

  The soft ferrite layer is formed by mixing soft ferrite powder on the surface of the high silicon steel plate with a magnetic steel sheet coating solution and applying the soft ferrite powder on the surface of the high silicon steel plate. After mixing and coating, the layer formed by mixing and coating the magnetic steel sheet coating liquid on the soft ferrite powder and the soft ferrite powder collide with the steel sheet at a high speed in vacuum or at room temperature to adhere to the surface And any one of the layers formed may be used.

At least one of SiO ₂ , CaO, Nb ₂ O ₅ , V ₂ O ₅ , ZrO ₂ , and MoO ₃ may be added to the soft ferrite layer.

  According to the present example, a high silicon steel sheet having excellent high frequency characteristics and having a high improvement in magnetism in the high frequency region can be manufactured by forming a MnZnNi soft ferrite layer having excellent high frequency characteristics on the surface of the high silicon steel sheet. .

It is a block diagram of the manufacturing method of the high silicon steel plate excellent in the magnetic property by one Example of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out. As will be readily understood by those having ordinary skill in the art to which the present invention pertains, the embodiments described below can be modified into various forms without departing from the concept and scope of the present invention. The same or similar parts as much as possible are denoted by the same reference numerals in the drawings.

  The terminology used below is merely for the purpose of reference to particular embodiments and is not intended to limit the invention. As used herein, the singular form includes the plural unless the sentence clearly indicates the opposite. As used herein, the meaning of “comprising” embodies certain characteristics, regions, integers, steps, operations, elements and / or components, and other specific properties, regions, integers, steps, operations, elements, It does not exclude the presence or addition of ingredients and / or groups.

  All terms including technical and scientific terms used below have the same meaning as commonly understood by those having ordinary skill in the art to which this invention belongs. Terms defined in the dictionary are further construed as having a meaning consistent with such technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

  The inventors of the present invention combined a strip casting and a warm rolling method, added Al instead of 6.5% Si, and produced a method for producing a high-silicon steel sheet having excellent workability and excellent magnetism. Invented and further researched, we developed a high-silicon steel plate with dramatically improved magnetism by forming a composite structure by forming a soft ferrite powder layer with excellent high-frequency characteristics on the surface layer.

Soft ferrite is a compound having a spinel type crystal structure, and the magnetic properties of the material easily change depending on the direction and magnitude of the magnetic field. Usually, Fe ₂ O ₃ iron oxide accounts for 60 to 70% by weight, and is classified into manganese zinc ferrite, nickel zinc ferrite, magnesium zinc ferrite and the like depending on the remaining metal oxide components. Hard ferrite compared to soft ferrite is a material in which the magnetic characteristics of the material do not easily change depending on the direction and magnitude of the magnetic field, and is generally called a permanent magnet. Fe ₂ O ₃ iron oxide accounts for about 90% by weight, and its use is divided according to the metal component added to improve other properties.

  In general, soft ferrite powder has high magnetic permeability and saturation magnetic flux density, has little magnetic deterioration at high temperature, and is excellent in magnetic stability. In particular, MnZnNi ferrite has high saturation magnetic flux density, magnetic permeability and low loss magnetic properties in a relatively wide frequency band of 100 KHz to 500 KHz. Ferrite uses powder as a core shape in sintered form.

  In the present invention, the magnetic property of the existing high silicon steel sheet could be dramatically improved by the method of forming these soft ferrites on the surface of the high silicon electromagnetic steel sheet. The high-frequency characteristic of the high silicon steel sheet has excellent magnetism in the frequency range of several hundred Hz to several KHz. It has been found that when a powder soft ferrite layer having excellent super-high frequency characteristics is formed on the surface of such a high silicon steel sheet, it has even more excellent characteristics.

  When an electromagnetic steel sheet is used as a core, energy loss mainly occurs in the surface layer, but iron loss can be greatly improved by forming a soft ferrite layer having excellent high-frequency characteristics on the surface.

  Hereinafter, a high silicon steel plate having excellent magnetic properties according to an embodiment of the present invention will be described.

  The high silicon electrical steel sheet having excellent magnetic properties, particularly in the high frequency region, according to an embodiment of the present invention, is a steel containing a large amount of Si and Al as 5.5% or more. After producing a final thickness by combining hot rolling, annealing heat treatment, warm rolling, etc., a MnZnNi soft ferrite layer is formed on the surface.

Specifically, the high silicon steel sheet is silicon steel composed of Si 4-7%, Al 0.1-3%, Si + Al in a weight ratio of 5.5-7.5%, and the balance Fe. The molten metal is strip-cast in a nitrogen or argon atmosphere, and the strip-cast strip is hot-rolled to produce a high-silicon steel plate, and then the hot-rolled high-silicon steel plate is subjected to nitrogen, argon, or hydrogen. After heat-treating in a non-oxidizing atmosphere of a mixed atmosphere of nitrogen and nitrogen, after hot rolling to a final thickness of 0.5 mm or less, the high silicon steel sheet is finally heat-treated at a temperature of 800 ° C. to 1200 ° C.,
In order to improve the magnetism in the high frequency region, a soft ferrite layer is formed on the surface of the high silicon steel plate manufactured to the final thickness.

  A method for manufacturing a high silicon steel sheet having excellent magnetic properties according to an embodiment of the present invention will be described.

According to one embodiment of the present invention, a method for manufacturing a high-silicon steel sheet having excellent magnetic properties is Si 4-7%, Al 0.1-3%, and the sum of Si + Al is 5.5-7.5% by weight. A strip casting step S10 for strip casting the molten silicon steel composed of the remaining Fe in a nitrogen or argon atmosphere;
A hot rolling step S20 for producing a high silicon steel sheet by hot rolling the strip cast strip;
Next, a heat treatment step S30 for heat-treating the hot-rolled high silicon steel sheet in a non-oxidizing atmosphere of nitrogen, argon, or a mixed atmosphere of hydrogen and nitrogen;
Next, in order to avoid the generation of ordered phases as much as possible, after rapid cooling to 100 ° C. at a cooling rate of 30 ° C./second or more, warm rolling including at least one heat treatment at 900 to 1200 ° C. is performed. The warm rolling temperature is 300 ° C. or higher, and the high silicon steel sheet is warm rolled in step S40 with a final thickness of 0.5 mm or less,
Next, a final heat treatment step S50 for performing a final heat treatment on the high silicon steel sheet at a temperature of 800 to 1200 ° C.,
After performing the final heat treatment step S50, the method includes a step S60 of forming a soft ferrite layer on the surface of the high silicon steel sheet manufactured to the final thickness in order to improve the magnetism in the high frequency region.

The manufacturing method of the high silicon steel plate that applies the method of forming the soft ferrite layer on the surface layer of the high silicon steel plate does not need to be limited to a method in which strip casting and warm rolling are combined. The present invention can be applied not only to a rapid solidification method by strip casting but also to a process that can be produced by steelmaking-continuous casting-hot rolling. However, in methods other than strip casting, there is room for the productivity to be extremely deteriorated due to generation of cracks during rolling. Further, the present invention can also be applied to a high silicon steel plate manufactured by the method of Japanese Patent Publication No. 38-26263, which uses SiCl ₄ gas to make high silicon steel by a CVD method.

  In the method for producing a high silicon steel sheet of the present invention, the lower the C content and the N content, the better the rollability and the more advantageous the magnetism.

  If the Si content is 4% or less, the magnetism is not good, and if it is 7% or more, processing is impossible.

  If the Al content is 0.1% or less, there is no effect of improving the rollability, and if it is 3% or more, the rollability is not good. If Si + Al is 5.5% or less, the high frequency characteristics are not good, and if it is 7.5% or more, processing is impossible.

  It is more preferable to perform hot rolling immediately after strip casting than to perform warm rolling immediately after casting by strip casting because the load of warm rolling can be reduced. Further, if a hot rolling mill is directly connected to the strip casting manufacturing apparatus, there is an advantage that it is not necessary to heat the strip separately. Most preferably, the strip is hot-rolled immediately after casting. However, it is more preferable that the strip is cooled and then treated in a separate line, instead of hot-rolling immediately without hot rolling. In addition to simply reducing the load of warm rolling, hot rolling is useful for warm rolling performed later by hot rolling to break down the cast structure and make the crystal grains fine.

  It is preferable to heat-treat the hot-rolled plate rather than immediately warm-rolling. When heat treatment is performed prior to warm rolling, stress generated during hot rolling is eliminated, heat treatment is performed in the region of the A2 irregular phase, and then rapid cooling is performed to suppress the formation of B2 and DO3 ordered phases. Will be better.

  According to the examination with respect to the warm rolling temperature, 300 ° C. became the critical temperature. When it becomes 300 degrees C or less, it becomes clear that there is almost no ductility, and if it is 300 degrees C or more, it can extend | stretch. A minimum of 350 ° C. is preferred for mass production.

  A high silicon steel sheet thinned to a final thickness of 0.5 mm or less by warm rolling is subjected to a final heat treatment to improve magnetism. If the heat treatment temperature is 800 ° C. or less, the crystal grains are not sufficiently grown and the iron loss is poor. If the heat treatment temperature is 1200 ° C. or higher, it is not preferable in terms of economy and productivity, and a surface oxide layer is easily formed even when a non-oxidizing atmosphere is used. .

  Manganese oxide, zinc oxide, nickel oxide, and MnZnNi-based soft ferrite made of Fe-based oxide are applied to the surface of the high silicon steel having the final thickness. The soft ferrite powder may be mixed and applied with a normal electrical steel sheet coating solution. After the soft ferrite powder is mixed with a phosphate binder and applied, the normal magnetic steel sheet coating solution is applied onto the soft ferrite powder. It may be applied.

  The thickness of the soft ferrite layer made of soft ferrite powder is 1 μm or more. If the thickness is 1 μm or less, there is no effect of forming the composite structure. If the thickness of the soft ferrite layer is 30 μm or more, there is a drawback that the surface layer is cracked when the steel sheet is punched, and the upper limit of the thickness is 30 μm.

  The demand for high-frequency electrical steel sheets used for iron core materials for high-frequency equipment is increasing. It is widely used in motors used in computers, dental power tools, motors in electric vehicles, reactors, transformers for new renewable energy, and generators. The frequency region in which a normal high-frequency electromagnetic steel sheet is in charge is several tens to several hundreds Hz, and the region in which high silicon steel is in charge is several hundred Hz to several KHz. On the other hand, at several tens of KHz or more, a powder sintered core using soft ferrite is used.

  The inventors have studied with the idea that forming a soft ferrite layer on the surface of high silicon steel not only improves the magnetism in the high frequency region that high silicon steel was responsible for, but also expands the usable frequency region. In the case where a soft ferrite layer of 1 μm or more is formed on the surface of high silicon steel, the magnetic properties of high silicon steel were successfully reduced. The soft ferrite layer is applied to both sides of the surface of the high silicon steel sheet in sheet form. The total thickness of the soft ferrite layers applied on both sides of the surface of the high silicon steel sheet must be 1 μm or more. However, it has been found that when the total thickness of both surfaces of the soft ferrite layer exceeds 30 μm, when the steel sheet is punched into a core form, the surface layer is crushed and it is difficult to maintain the surface layer.

  The soft ferrite layer can be formed by mixing soft ferrite powder with a normal magnetic steel sheet coating solution or by applying soft ferrite powder with a phosphate or polymer and applying it to a high silicon steel plate in liquid form. Thereafter, a method of applying with a normal magnetic steel sheet coating solution, a method of causing soft ferrite powder to collide with a steel sheet at a high speed in vacuum or at room temperature, and adhere to the surface can be used.

The soft ferrite layer is composed of so-called MnZnNi soft ferrite composed of manganese oxide, zinc oxide, nickel oxide and iron oxide. The soft _{ferrite, SiO 2, CaO, Nb 2} O 5, V 2 O 5, ZrO 2, MoO 3 and the like may be added at least one or more. These oxides have excellent magnetic properties in the high frequency region, and can greatly improve the magnetism of the high silicon steel in the surface layer of the high silicon steel plate.

  In order to sinter soft ferrite to produce a core, the shape of the sintered body is different for each core, and there is a drawback that high-temperature and high-pressure heat treatment is required when producing the core. However, the present invention has an advantage that a core can be produced by simply applying soft ferrite to the surface of a thin high-silicon steel plate and punching and assembling it to the required size.

[Example 1]
A high silicon steel alloy having a composition of 5.5% by weight and 5.5% Si and 1.0% Al was cast to a thickness of 2.0 mm using a vertical twin roll strip caster. A 2.0 mm thick strip was hot rolled to 1.0 mm using a hot rolling mill connected to a strip caster. The hot rolling start temperature is 1050 ° C.

  The hot-rolled high silicon steel sheet was heated at 1000 ° C. for 5 minutes in an atmosphere of 20% hydrogen and 80% nitrogen, and then rapidly cooled to room temperature at a cooling rate of 200 ° C./second.

  Thereafter, the surface oxide layer was removed by pickling with a hydrochloric acid solution. After reducing the thickness of the heat-treated high silicon steel sheet to 0.1 mm at a temperature of 400 ° C., the final magnetism is realized at 1000 ° C. for 10 minutes, hydrogen 20%, nitrogen 80%, dew point −10 ° C. After annealing in the following dry atmosphere, MnZnNi soft ferrite was applied to the surface layer, an insulating coating was applied again on the coating layer, and then cured to measure magnetism. The coating thickness is a combined value of the upper and lower surfaces of the steel plate. Table 1 shows the composition and magnetism of the soft ferrite.

  B50 (T) which measured the magnetism shown in Table 1 measured magnetic flux density, and it is evaluated that it has the magnetism which is so good that magnetic flux density is high. Moreover, W10 / 400 and W10 / 1000 were measured for iron loss at commercial frequencies, and it is evaluated that the lower the iron loss, the lower the magnetism.

  Here, B50 (T) indicates the value of magnetic flux density in units of Telsa when the strength of the magnetic field is 5000 amp (ampere) / m, and W10 / 400 (W / Kg) is the magnetic flux density value. When the value is 1.0 Telsa, the value of iron loss when the frequency is 400 Hz is shown. W10 / 1000 (W / Kg) is when the magnetic flux density value is 1.0 Telsa, the frequency is 1000 Hz. The value of the iron loss in the case is shown.

  If the coating thickness of the soft ferrite layer is less than 1 μm, the high frequency iron loss characteristic is poor and the effect of the soft ferrite coating is not achieved. If the coating thickness of the soft ferrite layer is 30 μm or more, the peeling phenomenon of the soft ferrite layer on the surface layer occurs, the surface roughness is not uniform, and the space factor decreases when laminated as a core. is there.

Claims (14)

In a weight ratio, Si 4-7%, Al 0.1-3%, Si + Al total is 5.5-7.5%, and the silicon steel melt composed of the remaining Fe is strip-casted under nitrogen or argon atmosphere A strip casting step, a hot rolling step of hot rolling the strip cast strip to produce a high silicon steel plate, and the hot rolled high silicon steel plate with nitrogen, argon, or hydrogen and nitrogen. A heat treatment stage in which heat treatment is performed in a non-oxidizing atmosphere of a mixed atmosphere; a warm rolling stage in which the heat-treated high silicon steel sheet is warm-rolled to a final thickness of 0.5 mm or less; and the high silicon steel sheet is heated to 800 ° C. to 1200 ° C. In a method for producing a high silicon steel sheet comprising a final heat treatment step of performing a final heat treatment at a temperature of ° C.,
After performing the final heat treatment step, high silicon having excellent magnetic properties including a step of forming a soft ferrite layer on the surface of a high silicon steel plate manufactured to a final thickness in order to improve magnetism in a high frequency region A method of manufacturing a steel sheet.   The method for manufacturing a high-silicon steel sheet with excellent magnetic properties according to claim 1, wherein the soft ferrite layer is formed on both surfaces of the surface of the high-silicon steel sheet manufactured to a final thickness.   The method for manufacturing a high-silicon steel sheet with excellent magnetic properties according to claim 2, wherein the soft ferrite layer is made of MnZnNi-based soft ferrite.   The method for producing a high-silicon steel sheet with excellent magnetic properties according to claim 3, wherein the MnZnNi-based soft ferrite is made of Mn oxide, Zn oxide, Ni oxide, and Fe oxide.   The method for producing a high-silicon steel sheet having excellent magnetic properties according to claim 2, wherein the total thickness of both surfaces of the soft ferrite layer is 1 µm or more and 30 µm or less. The soft ferrite layer forming step includes applying a soft ferrite powder to the surface of the high silicon steel plate mixed with a magnetic steel sheet coating solution,
After mixing and applying a soft ferrite powder and a phosphate binder to the surface of the high silicon steel sheet, mixing and applying a magnetic steel sheet coating solution on the soft ferrite powder; and
The soft ferrite powder is made to collide with a steel plate at a high speed in vacuum or normal temperature and adhere to the surface, and includes any one of the steps. A method for producing a high silicon steel sheet having excellent magnetic properties as described. 7. The magnetic material according to claim 6, wherein at least one of SiO ₂ , CaO, Nb ₂ O ₅ , V ₂ O ₅ , ZrO ₂ , and MoO ₃ is added to the soft ferrite layer. A method for producing a high silicon steel sheet having excellent properties. The silicon steel melt is strip cast in a nitrogen or argon atmosphere, and the strip cast strip is hot rolled to produce a high silicon steel plate, and then the hot rolled high silicon steel plate is nitrogen, argon, Alternatively, after heat-treating in a non-oxidizing atmosphere of a mixed atmosphere of hydrogen and nitrogen, after warm rolling to the final thickness, the high-silicon steel sheet produced by subjecting the high-silicon steel sheet to a final heat treatment,
A high silicon steel sheet with excellent magnetic properties, characterized in that a soft ferrite layer is formed on the surface of a high silicon steel sheet manufactured to a final thickness in order to improve magnetism in a high frequency region.   The high-silicon steel plate with excellent magnetic properties according to claim 8, wherein the soft ferrite layer is formed on both surfaces of a surface of a high-silicon steel plate manufactured to a final thickness.   The high-silicon steel sheet having excellent magnetic properties according to claim 9, wherein the soft ferrite layer is made of MnZnNi-based soft ferrite.   The high-silicon steel sheet having excellent magnetic properties according to claim 10, wherein the MnZnNi-based soft ferrite is made of Mn oxide, Zn oxide, Ni oxide, and Fe oxide.   The high silicon steel sheet with excellent magnetic properties according to claim 9, wherein the total thickness of both surfaces of the soft ferrite layer is 1 µm or more and 30 µm or less.   The soft ferrite layer is formed by mixing soft ferrite powder on the surface of the high silicon steel plate with a magnetic steel sheet coating solution and applying the soft ferrite powder on the surface of the high silicon steel plate. After mixing and coating, the layer formed by mixing and coating the magnetic steel sheet coating liquid on the soft ferrite powder and the soft ferrite powder collide with the steel sheet at a high speed in vacuum or at room temperature to adhere to the surface The high-silicon steel sheet having excellent magnetic properties according to any one of claims 9 to 12, wherein the high-silicon steel sheet is any one of the above-described layers. The magnetic layer according to claim 13, wherein at least one of SiO ₂ , CaO, Nb ₂ O ₅ , V ₂ O ₅ , ZrO ₂ , and MoO ₃ is added to the soft ferrite layer. High silicon steel plate with excellent properties.

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