KR20180073307A - Non-oriented electrical steel steet laminate and manufacturing method for the same - Google Patents

Abstract

The present invention provides a non-oriented electrical steel sheet laminate with excellent post-heat treatment magnetic properties and strength, and manufacturing method thereof. According to one embodiment of the present invention, the non-oriented electrical steel sheet laminate is formed by stacking two or more non-oriented electrical steel sheets, which comprise: 2 to 4 weight percent of Si; 2 weight percent or less of Al (excluding 0 weight percent); 3.0 weight percent or less of Mn (excluding 0 weight percent); 0.1 weight percent or less of P (excluding 0 weight percent); 0.005 weight percent or less of C (excluding 0 weight percent); 0.005 weight percent or less of S (excluding 0 weight percent); 0.003 weight percent or less of N (excluding 0 weight percent); 0.005 weight percent or less of Ti (excluding 0 weight percent); 0.005 weight percent or less of Nb (excluding 0 weight percent); 0.0001 to 0.003 weight percent of Mg; 0.0005 to 0.003 weight percent of B; and the remainder being Fe and unavoidable impurities. Moreover, an inorganic adhesive layer is formed between the non-oriented electrical steel sheets.

Description

TECHNICAL FIELD [0001] The present invention relates to a non-oriented electrical steel sheet laminate and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

A non-oriented electrical steel sheet laminate and a manufacturing method thereof. More specifically, the present invention relates to a non-oriented electrical steel sheet laminate which is widely used as an important component of a rotating machine, and which is excellent in magnetic properties and strength after heat treatment, and a manufacturing method thereof.

In general, the nonoriented electric steel sheet is an important iron core material necessary for converting electrical energy into mechanical energy in a rotating machine. Therefore, it is important to have a magnetic property, that is, a low iron loss for energy saving. Here, iron loss is the energy that turns into heat in the energy conversion process, so the lower the energy loss, the more efficient it is.

Recently, technologies for converting existing internal combustion engine vehicles into HEV (hybrid vehicle) / EV (electric vehicle) have been rapidly developed as measures to reduce fossil fuel shortage and greenhouse gas reduction. These HEV / EVs are cars that can convert some or all of the drive system into electric motors to reduce the consumption of gasoline or diesel fuel, which is a fuel for existing internal combustion engines, while achieving better fuel economy.

The motor used in such a car is rotated at a high speed when traveling at a high speed. Therefore, the non-oriented electrical steel sheet, which is an iron core material of the motor, should have a low iron loss at high frequency. In general, the term high-frequency iron loss means that the core loss at a frequency above 200Hz, but the car non-oriented electrical steel sheet is mainly used for the value of the conventional W _10/400. Also, in the field of home appliances, the iron loss of such a high frequency iron loss region band gradually becomes important due to adoption of BLDC motor.

In order to improve the high-frequency iron loss, the alloy elements such as Si, Al, and Mn, which are the resistivity elements of the electric steel sheet, should be raised, impurities should be reduced to facilitate the movement of the magnetic domains, and the thickness of the electric steel sheet must be reduced.

However, when a non-magnetic alloy element such as Si, Al, and Mn is included in a high content, rolling becomes difficult and there is a limit. If the thickness is reduced, the production unit price and the processing cost of the customer side are difficult to increase.

In addition, since the rotor of the motor in which the permanent magnet is inserted generates a weak portion at high speed rotation, it is inevitably necessary to consider the strength. Especially, recently, the rotor speed has reached tens of thousands of RPM, and various studies for increasing the strength have been conducted. As a result, high strength products have been developed. However, in the case of high strength steels, iron loss is high due to the fine grain size, There is a problem that it can not be used, and there is a problem that the post-shipment residue increases and the rate of occurrence of the error increases.

An embodiment of the present invention is to provide a method of manufacturing a non-oriented electrical steel sheet laminate which simultaneously improves high-frequency iron loss and strength by providing an electrical steel sheet with an insulating layer added therein.

An embodiment of the present invention is characterized in that an insulating layer is inserted in the middle of a final electrical steel sheet to prevent an increase in the production cost due to thinning and increase the processing cost of the customer so that the non- S body.

A method for producing a non-oriented electrical steel sheet laminate according to an embodiment of the present invention comprises: 2 to 4% of Si, 2% or less of Al (excluding O%), 3.0% , P: not more than 0.1% (excluding O%), C: not more than 0.005% (excluding O%), S: not more than 0.005% (excluding O%), N: not more than 0.003% O%), Nb: 0.005% or less (excluding O%), Mg: 0.0001 to 0.003%, and B: 0.0005 to 0.003%, the balance being Fe and other unavoidable impurities; Hot rolling the slab to produce a hot rolled sheet; Cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; Laminating the cold rolled sheets by inserting an adhesive in the middle of each layer; Re-cold-rolling the double-ply cold-rolled sheet to manufacture a multi-layer cold-rolled sheet, and finally annealing the multi-layered cold-rolled sheet.

In the step of heating the slab, it may be heated at 1,050 ° C to 1,200 ° C.

The step of producing the hot rolled sheet can be hot rolled so that the thickness of the hot rolled sheet is 2.5 mm or less.

After the step of producing the hot-rolled steel sheet, the hot-rolled steel sheet may further include annealing the hot-rolled steel sheet at a temperature of 850 to 1,150 캜.

The adhesive may comprise an oxide or a nitride.

The adhesive may include at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO, and ZrO ₂ .

After the step of laminating, cold rolling and annealing may be further included.

In the step of producing the multi-layered cold-rolled sheet, the thickness of the multi-layered cold-rolled sheet is 0.2 to 0.4 mm and the surface roughness Ra of the multi-layered cold-rolled sheet can be re-cold-rolled to 1.5 탆 or less.

The final annealing step may be performed at a temperature of 850 to 1050 캜.

After the final annealing step, the step of finishing annealing may be further included.

The non-oriented electrical steel sheet laminate according to one embodiment of the present invention may contain, by weight%, 2 to 4% of Si, 2% or less of Al (exclusive of O%), 3.0% C: not more than 0.005% (excluding O%), S: not more than 0.005% (excluding O%), N: not more than 0.003% (excluding 0%) Ti: not more than 0.005% ), Nb: 0.005% or less (excluding O%), 0.0001 to 0.003% of Mg, and 0.0005 to 0.003% of B, the remainder being Fe and other unavoidable impurities, An inorganic adhesive layer is formed between the non-oriented electrical steel sheets.

The thickness of each of the non-oriented electrical steel sheets may be 0.3 mm or less.

The non-oriented electrical steel sheet may have an average grain size of 20 mu m or less.

The inorganic adhesive layer may comprise an oxide or nitride.

The inorganic adhesive layer may include at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO, and ZrO ₂ .

The inorganic adhesive layer may have a thickness of 1 탆 or more.

The thickness of the entire laminate may be 0.2 to 0.4 mm.

By producing the non-oriented electrical steel sheet laminate according to an embodiment of the present invention, it is possible to provide a non-oriented electrical steel plate laminate having high-frequency characteristics and strength at the same time.

When the non-oriented electrical steel sheet laminate is formed into a laminated structure according to an embodiment of the present invention, iron loss and strength characteristics are improved compared to the conventional non-oriented electrical steel sheet of the same component.

The non-oriented electrical steel sheet laminate according to one embodiment of the present invention can contribute to the improvement of the efficiency of a BLDC motor or an automobile drive motor driven at a high frequency.

1 is a schematic view illustrating a process for manufacturing a cold-rolled sheet from a cold-rolled sheet in the manufacture of a non-oriented electrical steel sheet laminate according to an embodiment of the present invention.
Fig. 2 is a photograph of a section of the inventive material 1 in the thickness direction after final annealing with a scanning electron microscope (SEM). Fig.
Fig. 2 is a photograph of a section of the inventive material 1 in the thickness direction after the annealing annealing with a scanning electron microscope (SEM). Fig.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

When referring to a portion as being "on" or "on" another portion, it may be directly on or over another portion, or may involve another portion therebetween. In contrast, when referring to a part being "directly above" another part, no other part is interposed therebetween.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Unless otherwise stated,% means% by weight, and 1 ppm is 0.0001% by weight.

In an embodiment of the present invention, the term further includes an additional element, which means that an additional amount of the additional element is substituted for the remaining iron (Fe).

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The non-oriented electrical steel sheet laminate according to one embodiment of the present invention may contain, by weight%, 2 to 4% of Si, 2% or less of Al (exclusive of O%), 3.0% C: not more than 0.005% (excluding O%), S: not more than 0.005% (excluding O%), N: not more than 0.003% (excluding 0%) Ti: not more than 0.005% ), Nb: 0.005% or less (excluding O%), 0.0001 to 0.003% of Mg, and 0.0005 to 0.003% of B, the remainder being Fe and other unavoidable impurities, An inorganic adhesive layer is formed between the non-oriented electrical steel sheets.

First, the reason why the range of the component elements of the non-oriented electrical steel sheet 10 and the addition ratio between the element elements are limited will be described.

Si: 2 to 4 wt%

Silicon (Si) enhances the resistivity of the material and lowers the iron loss, and if too much is added, the hardness of the material increases and the productivity and saturation are heated, which is not desirable. Conversely, when added too little, strength and high frequency iron loss can be caused by heat. Therefore, Si may be included in the above-mentioned range.

Al: 2.0 wt% or less

Aluminum (Al) increases the resistivity of the material to lower the iron loss and suppress the formation of fine nitride. However, if it is added too much, it will cause problems in all processes such as steelmaking, continuous casting and hot rolling, and the productivity is greatly lowered. Therefore, Al can be included in the above-mentioned range.

Mn: 3.0 wt% or less

Manganese (Mn) improves the resistivity of the material and improves iron loss and forms sulphide. When added too little, MnS is precipitated finely and deteriorates magnetism. If too much is added, the magnetic flux density may be lowered. Therefore, Mn may be included in the above-mentioned range.

P: not more than 0.1% by weight

Phosphorus (P) is mostly employed in the steel to improve the iron loss, but if it is included in large amounts, it is undesirable because it segregates in the grain boundaries and lowers the toughness of the material and lowers the productivity and saturation. Therefore, P may be included in the above-mentioned range.

C: 0.005 wt% or less

If the amount of carbon (C) exceeds 0.005% by weight, the effect due to magnetic decline due to magnetic aging is more effective, and it is necessary to control the amount of carbon (C) to 0.005% by weight or less. In particular, in an embodiment of the present invention, since the magnetism is improved through crystal growth after annealing annealing performed by the customer, it is necessary to extremely reduce the carbide, and therefore, it is necessary to control the content of C to 0.005 wt% or less.

S: 0.005 wt% or less

Since sulfur (S) forms fine precipitates MnS and CuS to deteriorate magnetic properties and further inhibits grain growth during annealing annealing, it is preferable to control the ratio to a low level, and it is possible to perform a refining process in steelmaking as an indispensable element in steel However, the S content is limited to 0.005% by weight or less in one embodiment of the present invention due to an increase in refining cost or the like.

N: not more than 0.003% by weight

Since nitrogen (N) forms fine and long AlN precipitates inside the base material to cause iron loss, and further inhibits grain growth during refining annealing, it is preferable to contain as little as possible. In one embodiment of the present invention, the N content is 0.003 wt% %.

Ti: 0.005 wt% or less

However, in the case of the present invention, it is preferable that iron (Ti) is added to C, N or the like to lower the iron loss by itself and further inhibits grain growth during refining annealing. And 0.005 wt% or less in the examples.

Nb: 0.005 wt% or less

Niobium (Nb) also combines with C, N and the like in combination with Ti to increase the strength. In the case of the present invention, however, it is preferable that the niobium (Nb) is contained as low as possible because it lowers the iron loss per se and hinders grain growth during annealing. In one embodiment of the invention, it is limited to 0.005% by weight or less.

Mg: 0.0001 to 0.003 wt%

Magnesium (Mg) is an impurity that can be incorporated from iron, refractory and the like, and suppresses crystal growth by forming oxides and other additive elements and precipitates. If it contains too little Mg, it can be heat-resistant in terms of strength. When Mg is included too much, it is difficult to secure crystal growth ability in the annealing annealing. Therefore, Mg may be included in the above-mentioned range.

B: 0.0005 to 0.003 wt%

Boron (B) is an element which bonds with N or the like and improves toughness of the material, but inhibits crystal growth. If you include too little B, it can be heat-resistant. If B is included too much, it is difficult to secure crystal growth. Therefore, B may be included in the above-mentioned range.

Other impurity elements

In addition to the above-mentioned elements, inevitably incorporated impurities such as V and Cu may be contained, and in some cases precipitates are formed to inhibit crystal growth, and therefore, it should be limited to 0.1 wt% or less.

In one embodiment of the present invention, the components of the slab may be substantially the same as the components of the non-oriented electrical steel sheet described above, since the composition of the non-oriented electrical steel sheet laminate is substantially unchanged.

The thickness of each of the non-oriented electrical steel sheets may be 0.3 mm or less. The lower the thickness of each layer, the better the high-frequency iron loss.

The non-oriented electrical steel sheet may have an average grain size of 20 mu m or less. Strength and puncture property are improved in the average crystal grain diameter in the above-mentioned range, and high strength characteristics suitable for high-speed rotation motors are obtained. More specifically, it may be 9 to 15 占 퐉.

An inorganic adhesive layer (20) is formed between the non-oriented electrical steel sheets (10).

The inorganic adhesive layer may comprise an oxide or nitride. Specifically, the inorganic adhesive layer may include at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO, and ZrO ₂ .

The inorganic adhesive layer may have a thickness of 1 탆 or more. As a result, the inorganic adhesive layer can maintain a higher insulation performance.

The thickness of the entire laminate may be 0.2 to 0.4 mm. Considering the cost increase factor, it is effective to manufacture the laminate with a thickness of 0.2 mm or more. When the thickness exceeds 0.4 mm, the laminate is not suitable for high frequency, and therefore, the thickness can be 0.2 to 0.4 mm.

The average roughness (Ra) of the surface of the laminate may be 1.5 탆 or less. If the average roughness (Ra) is too high, the iron loss may be inferior.

A method for producing a non-oriented electrical steel sheet laminate according to an embodiment of the present invention comprises: 2 to 4% of Si, 2% or less of Al (excluding O%), 3.0% , P: not more than 0.1% (excluding O%), C: not more than 0.005% (excluding O%), S: not more than 0.005% (excluding O%), N: not more than 0.003% O%), Nb: 0.005% or less (excluding O%), Mg: 0.0001 to 0.003%, and B: 0.0005 to 0.003%, the balance being Fe and other unavoidable impurities; Hot rolling the slab to produce a hot rolled sheet; Cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; Laminating the cold rolled sheets by inserting an adhesive in the middle of each layer; Re-cold-rolling the double-ply cold-rolled sheet to manufacture a multi-layer cold-rolled sheet, and finally annealing the multi-layered cold-rolled sheet.

Hereinafter, a method of manufacturing the non-oriented electrical steel sheet laminate according to one embodiment of the present invention will be described in detail for each step.

First, molten steel controlled within the above-described composition range is solidified in a continuous casting process to produce a slab. Since the components of the slab are substantially the same as those of the above-described non-oriented electrical steel sheet, a duplicate description will be omitted.

The slab is charged into a heating furnace and heated at 1,050 ° C to 1,200 ° C. Since it is preferable to reheat at a low temperature as much as possible in order to prevent redeposition of the precipitate upon heating, it is necessary to heat at 1,200 占 폚 or less. When the temperature is less than 1,050 占 폚, the deformation resistance during hot rolling is too large.

Next, the slab is hot-rolled to produce a hot-rolled sheet. The hot-rolled sheet can be hot rolled so that the thickness of the hot-rolled sheet is 2.5 mm or less. This is to minimize the formation of unfavorable (111) recrystallized texture when the rolling reduction is high in the subsequent cold rolling.

Next, the hot-rolled sheet can be subjected to hot-rolled sheet annealing if necessary. At this time, the hot-rolled sheet can be annealed at a temperature of 850 to 1,150 캜. If the annealing temperature of the hot-rolled sheet is less than 850 캜, the structure does not grow or grows finely and the synergistic effect of the magnetic flux density is small. If the annealing temperature exceeds 1,150 캜, the magnetic properties are rather deteriorated. Can be bad. Therefore, it can be limited to the above-mentioned temperature range. More specifically, the hot-rolled sheet annealing temperature may be 950 to 1,150 ° C.

Next, the hot-rolled sheet is cold-rolled to produce a cold-rolled sheet. At this time, the thickness of the cold-rolled sheet may be 1 mm or less. The hot rolled sheet can be pickled and then cold rolled.

Next, cold-rolled sheets are laminated, and an adhesive is inserted in the middle of each layer to laminate. As disclosed in FIG. 1, the cold rolled sheet can be degreased before the adhesive is inserted. The adhesive may comprise an oxide or a nitride. This is because it is necessary to maintain insulation at the time of final annealing to be described later. In order to sufficiently adsorb the inorganic material to the steel sheet and maintain the adhesion state during rolling and annealing, proper use of a medium such as water or resin is essential. Specifically, the adhesive may include at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO, and ZrO ₂ . They may be present in the form of slurries with water or a resin.

In order to make the steel sheet to have a uniform thickness by using an adhesive, it may further include a lamination process, a rolling process and an annealing process. However, if it is directly connected to the re-cold rolling step after lamination, it is possible to produce a laminated cold-rolled sheet by heat and pressure generated during re-rolling, and the additional rolling and annealing step may be omitted.

Next, the double-ply cold-rolled sheet is re-cold-rolled to produce a multi-layer cold-rolled sheet. The thickness of the multilayer cold-rolled sheet is 0.2 to 0.4 mm, and the surface roughness (Ra) of the multilayer cold-rolled sheet is 1.5 占 퐉 or less. If the average roughness exceeds 1.5 탆, the insulating effect by the adhesive layer may be lost after re-cold-rolling. When the thickness of the multilayer cold-rolled sheet is too thick, excellent high-frequency iron loss characteristics can not be obtained. When the thickness of the multilayer cold-rolled sheet is too thin, the degree of improvement of the iron loss is not so large as compared with the non-oriented electric steel sheet of a single layer.

Next, the multi-layer cold rolled sheet is finally annealed. The final annealing temperature is desirably 800 DEG C or less since it is aimed to have a high strength before the annealing annealing and to have a high-frequency low iron loss through crystal growth after the annealing. In particular, when the final annealing is performed at a temperature of 800 ° C or lower, there is little distortion during annealing, and the solution can be stably maintained, which is advantageous for production of products. When the final annealing temperature is 800 DEG C or lower, the average crystal grain diameter becomes 20 mu m or less, and the strength and pitting property are improved, so that high strength characteristics suitable for high-speed rotating motors are obtained. When the non-oriented electrical steel sheet laminate having completed the final annealing is utilized, it can be used for the rotor.

After final annealing, it may further include annealing annealing. The refining annealing can be performed at a temperature range of 650 to 850 캜 and can be performed in a nitrogen atmosphere at 100% by volume. When the calcination annealing is carried out, the average crystal grain size becomes 100 탆 or less, and a structure favorable to iron loss is obtained. When the non-oriented electrical steel sheet laminate having the finishing annealing is utilized, it can be used in the stator.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these embodiments are only for illustrating the present invention, and the present invention is not limited thereto.

Example 1

The steel sheet according to any one of claims 1 to 3, wherein the steel sheet contains 3.4% Si, 0.6% Al, 0.5% Mn, 0.002%, 0.002%, 0.001% B, and the balance of Fe and other inevitably incorporated impurities.

The slab was heated at a temperature of 1150 DEG C for 90 minutes, and hot-rolled to produce a hot-rolled steel sheet having a thickness of 2.0 mm. The hot-rolled sheet was cold-rolled to the thickness shown in Table 1 below. Thereafter, an intermediate layer consisting of two layers of MgO, resin and water was inserted into the intermediate layer, followed by light rolling, annealing at around 400 ° C., re-cold rolling to 0.27 mm, and hydrogenation at 20 ° C. for 1 minute at 750 ° C., , And 80 volume% nitrogen, and then the yield strength and average grain diameter were measured by tensile test and cross - sectional optical image analysis.

FIG. 2 is a photograph of a section of the inventive material 1 in the thickness direction after final annealing by a scanning electron microscope (SEM).

After the measurement, annealing was performed for 1 hour at 750 DEG C in a nitrogen atmosphere of 100 vol%.

Fig. 3 is a photograph of a section of the inventive material 1 in the thickness direction after the refining annealing with a scanning electron microscope (SEM). Fig. The iron loss after the annealing was measured and summarized in Table 1 below.

After iron surface was cleaned, steel loss was measured at 1.0 Tesla and 400 Hz using single sheet method.

B
content
(weight%) Mg content
(weight%) Cold rolled plate
thickness
(mm) Cold rolled laminates average roughness
(탆) Size of grain before annealing
(탆) Strength before annealing annealing
(MPa) Iron loss after annealing annealing
W _10/400
(W / Kg) Remarks 0.0005 0.0014 0.7 0.8 14 596 9.1 Inventory 1 0.0012 0.0013 0.7 0.8 13 599 9.2 Inventory 2 0.0025 0.0014 0.7 0.8 9 603 9.5 Inventory 3 0.0035 0.0015 0.7 0.8 8 605 11.5 Comparison 1 0.0007 0.0022 0.7 0.8 13 601 9.4 Invention 4 0.0008 0.0028 0.7 0.8 12 605 9.5 Invention Article 5 0.0003 0.0035 0.7 0.8 14 610 11.6 Comparative material 2 0.0007 0.0018 0.5 0.8 13 597 8.5 Inventions 6 0.0007 0.0019 0.8 0.7 13 598 9.2 Invention 7 0.0006 0.0017 1.2 0.8 13 604 10.5 Comparative material 3 0.0008 0.0017 1.5 0.7 13 600 11.6 Comparison 4 0.0006 0.0017 0.7 One 12 598 9.2 Invention 8 0.0006 0.0020 0.7 1.3 14 598 9.6 Invention 9 0.0006 0.0019 0.7 1.7 13 604 10.8 Comparative material 5

As shown in Table 1, in the case of inventive materials 1 to 5, the iron loss was not more than 10 W / Kg after the refining annealing to not more than 0.003 wt% of the content of B, Mg and the like. On the other hand, in the case of the comparative materials 1 and 2, the content of either B or Mg was higher than 0.003 wt%, and the iron loss was high after annealing annealing. This is because B or Mg forms a precipitate and grain growth is slowed during refining annealing (SRA). In the case of Inventive materials 6 to 9, in which the thickness of the cold-rolled sheet is not more than 1 mm and the roughness of the cold-rolled laminated board is not more than 1.5 탆, the properties after heat treatment are good. However, when the thickness exceeds 1 mm and the roughness of the cold- In the case of 3 to 5, the iron loss was lowered after the relative annealing. This is because when the thickness of the cold rolled steel sheet is high, insulation breakdown occurs due to rolling.

It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. It will be understood that the invention may be practiced. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: non-oriented electrical steel sheet laminate
10: Non-oriented electrical steel sheet
20: Adhesive layer

Claims (17)

(Excluding O%), Mn: not more than 3.0% (excluding O%), P: not more than 0.1% (excluding O%), C: not more than 0.005% (Excluding O%), S: not more than 0.005% (excluding O%), N: not more than 0.003% (excluding 0%) Ti: not more than 0.005% 0.0001 to 0.003% of B and 0.0005 to 0.003% of B, the remainder comprising Fe and other unavoidable impurities;
Hot rolling the slab to produce a hot rolled sheet;
Cold-rolling the hot-rolled sheet to produce a cold-rolled sheet;
Laminating the cold-rolled sheet by inserting an adhesive in the middle of each layer;
Re-cold-rolling the laminated cold-rolled sheet to produce a multi-layer cold-rolled sheet and
And finally annealing the multi-layered cold-rolled sheet. The method according to claim 1,
Wherein the slab is heated at a temperature of 1,050 to 1,200 DEG C in the step of heating the slab. The method according to claim 1,
Wherein the step of producing the hot-rolled steel sheet comprises hot-rolling the steel sheet so that the thickness of the hot-rolled steel sheet is not more than 2.5 mm. The method according to claim 1,
Further comprising the step of annealing the hot rolled sheet at a temperature of 850 to 1,150 占 폚 after the step of producing the hot rolled sheet. The method according to claim 1,
Wherein the adhesive comprises an oxide or a nitride. The method according to claim 1,
Wherein the adhesive comprises at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO, and ZrO ₂ . The method according to claim 1,
Further comprising the step of cold rolling and the step of annealing after the step of laminating the non-oriented electrical steel plate laminate. The method according to claim 1,
In the step of producing the multi-layered cold-rolled sheet, the thickness of the multi-layered cold-rolled sheet is 0.2 to 0.4 mm and the average roughness (Ra) of the surface of the multi-layered cold- Way. The method according to claim 1,
Wherein the final annealing is performed at a temperature of 850 to 1050 캜. The method according to claim 1,
Further comprising the step of refining and annealing after the final annealing step. (Excluding O%), Mn: not more than 3.0% (excluding O%), P: not more than 0.1% (excluding O%), C: not more than 0.005% (Excluding 0%) Ti: 0.005% or less (excluding O%), Nb: 0.005% or less (excluding O%), Mg: 0.0001 to 0.003% of B, and 0.0005 to 0.003% of B, the balance being a laminate of two or more layers of non-oriented electrical steel sheets containing Fe and other unavoidable impurities,
Wherein an inorganic adhesive layer is formed between the non-oriented electrical steel sheets. 12. The method of claim 11,
Wherein the thickness of each of the non-oriented electrical steel sheets is 0.3 mm or less. 12. The method of claim 11,
Wherein the non-oriented electrical steel sheet has an average grain size of 20 mu m or less. 12. The method of claim 11,
Wherein the inorganic adhesive layer comprises an oxide or a nitride. 12. The method of claim 11,
Wherein the inorganic adhesive layer comprises at least one of Al ₂ O ₃ , AlN, SiO ₂ , BN, MgO and ZrO ₂ . 12. The method of claim 11,
Wherein the inorganic adhesive layer has a thickness of 1 占 퐉 or more. 12. The method of claim 11,
Wherein the thickness of the whole laminate is 0.2 to 0.4 mm and the average roughness (Ra) of the surface of the laminate is 1.5 탆 or less.

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