KR102176355B1 - Insulating coating composition for electrical steel sheet and electrical steel sheet comprising insulating coating - Google Patents

Abstract

(화학식 1에서 R¹ 및 R²는 각각 독립적으로, 수소, 직쇄형 또는 분지형 알킬기, 시클로 알킬기, 알케닐기, 알키닐기, 아릴기, 헤테로아릴기, 알콕시기 또는 아미노알킬기이고, L는 직접 결합 또는 2가의 연결기이다. m은 1 내지 4의 정수이고, n은 4-m이다.)An electrical steel sheet substrate according to an embodiment of the present invention and an insulating film positioned on one or both sides of the electrical steel sheet substrate are included, and the insulating film includes a silane compound and a hydroxide metal represented by Formula 1 below.
[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

Description

Insulation coating composition for electrical steel sheet and electrical steel sheet including insulation coating {INSULATING COATING COMPOSITION FOR ELECTRICAL STEEL SHEET AND ELECTRICAL STEEL SHEET COMPRISING INSULATING COATING}

It relates to an electrical steel sheet comprising an insulating coating composition and an insulating coating for electrical steel sheet. More specifically, it relates to an electrical steel sheet comprising an insulating coating composition and an insulating coating for an electrical steel sheet excellent in heat resistance and thermal conductivity during stress relief annealing, using a silane compound containing a specific chemical structure.

The insulating film of an electrical steel sheet used for a motor or a transformer is required not only for interlayer resistance but also for various characteristics. For example, it is convenience during processing and molding, stability during storage and use. In addition, since the electrical steel sheet is used for various purposes, various insulating films have been developed according to the use.

For example, when punching, shearing, bending, or the like is performed on an electrical steel sheet, magnetic properties are deteriorated due to residual deformation. Therefore, stress relief annealing (SRA) is sometimes performed at high temperatures to restore deteriorated magnetic properties. Therefore, the insulating film is not peeled off during stress relief annealing and needs heat resistance to maintain intrinsic electrical insulation.

As a previously known insulating coating composition, chromic anhydride, magnesium oxide, acrylic resin, or acrylic-styrene copolymer resin was mixed and applied to improve corrosion resistance and insulation. However, there is a limit to satisfying the heat resistance during stress relief annealing required recently with such an insulating coating composition.

In addition, a method of improving adhesion during stress relief annealing by using metal phosphate as a main component of the insulating coating composition has been proposed. However, this method has a problem that whitening defects are generated on the surface due to the characteristic of phosphate having strong absorption resistance, and thus dust is generated during product processing, and heat resistance is rather inferior to the area where whitening defects occur.

It provides an electrical steel sheet comprising an insulating film composition and an insulating film for electrical steel sheet. More specifically, it provides an electrical steel sheet comprising an insulating coating composition and an insulating coating for an electrical steel sheet excellent in heat resistance and thermal conductivity during stress relief annealing by using a silane compound containing a specific chemical structure.

The electrical steel sheet according to an embodiment of the present invention includes an electrical steel sheet substrate and an insulating film located on one or both sides of the electrical steel sheet substrate, and the insulating film includes a silane compound represented by the following formula (1) and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

The silane compound may be represented by the following formula (2).

(In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly It is a bond or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

Silane compounds include triacetoxy(methyl)silane, triacetoxy(vinyl)silane, and dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di(methacroyloxy-1- ethoxy) silane) and 3- (trimethoxysilyl) propyl methacrylate (3- (trimethoxysilyl) propylmethacrylate) may be included.

The metal hydroxide is Ni(OH) ₂ , Co(OH) ₂ , Cu(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , Pd(OH) ₂ , In(OH) ₃ , (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ , Bi(OH) ₃ and Sn(OH) ₂ It may contain one or more of.

The insulating film may further include a metal nitride, and may include 0.1 to 40% by weight of a metal nitride, 25 to 75% by weight of a silane compound, and 0.5 to 60% by weight of a metal hydroxide.

The metal nitride may include one or more of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

The electrical steel sheet may satisfy the following General Formula 1.

[General Formula 1]

20≤ TC ≤ 200 W/mK

(In the general formula 1, TC represents a thermal conductivity value measured by induction heating a 600×400mm specimen at 230° C. and PPMS (Physical Property Measurement System).)

The electrical steel sheet substrate is C: 0.01% by weight or less, Si: 6.0% by weight or less, P: 0.5% by weight or less, S: 0.005% by weight or less, Mn: 0.1 to 1.0% by weight, Al: 0.40 to 2.0% by weight, N: 0.005% by weight or less, Ti: 0.005% by weight or less, and Sb, Sn, Ni or a combination thereof: 0.01 to 0.15% by weight, and may include Fe and inevitable impurities as the balance.

The insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by the following Formula 1 and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

A metal nitride may be further included, and, based on a solid content, 0.1 to 40% by weight of a metal nitride, 25 to 75% by weight of a silane compound, and 0.5 to 60% by weight of a metal hydroxide may be included.

The metal nitride may include one or more of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

A method of manufacturing an electrical steel sheet according to an embodiment of the present invention includes the steps of preparing a hot-rolled sheet by hot-rolling a slab, undergoing cold-rolling, and then preparing a steel sheet having finished annealing; And applying an insulating film composition to the steel sheet to form an insulating film, wherein the insulating film composition includes a silane compound represented by Formula 1 below and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

The electrical steel sheet on which the insulating film is formed may satisfy the following General Formula 1.

[General Formula 1]

20≤ TC ≤ 200 W/mK

(In the general formula 1, TC denotes a thermal conductivity value measured by induction heating a 600x400mm specimen at 230°C and using a PPMS (Physical Property Measurement System).)

According to an embodiment of the present invention, an electrical steel sheet having excellent iron loss characteristics can be obtained after forming an insulating film.

According to one embodiment of the present invention, it is possible to obtain an electrical steel sheet excellent in the drop ratio.

According to an embodiment of the present invention, an insulating film having excellent adhesion and peeling resistance can be obtained even after stress relief annealing (SRA).

According to one embodiment of the present invention, an electrical steel sheet having excellent thermal conductivity can be manufactured, and products such as motors manufactured using the electrical steel sheet are excellent in efficiency.

1 is a schematic view of a cross section of an electrical steel sheet according to an embodiment of the present invention.
Figure 2 is a flow chart of a method for manufacturing an electrical steel sheet according to an embodiment of the present invention.
3 is a scanning electron microscope (SEM) photograph of a cross section of an electrical steel sheet prepared in Example 2.
4 is a scanning electron microscope (SEM) photograph of a cross section of an electrical steel sheet prepared in Comparative Example 2.
5 is a FT-IR-RAS analysis result of the electrical steel sheet film prepared in Example 2.

Terms such as first, second and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for referring only to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of “comprising” as used in the specification specifies a specific characteristic, region, integer, step, action, element and/or component, and the presence of another characteristic, region, integer, step, action, element and/or component, or It does not exclude additions.

When a part is referred to as being "on" or "on" another part, it may be directly on or on another part, or other parts may be involved in between. In contrast, when a part is referred to as being “directly above” another part, no other part is intervened.

Although not defined differently, 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 the present invention belongs. Terms defined in a commonly used dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal meaning unless defined.

In the description of the group (atomic group) in the present specification, the notation that does not describe substituted or unsubstituted includes not only having no substituent but also having a substituent. For example, the term "alkyl group" includes not only an alkyl group not having a substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

In the present specification, unless otherwise defined, "substituted" is a C1 to C30 alkyl group; C2 to C30 alkenyl group, C2 to C30 alkynyl group, C1 to C10 alkylsilyl group; C3 to C30 cycloalkyl group; C6 to C30 aryl group; C1 to C30 heteroaryl group; C1 to C10 alkoxy group; Silane group; Alkylsilane group; Alkoxysilane group; Amine group; Alkylamine group; Arylamine group; It means substituted with an ethyleneoxyl group or a halogen group.

In the present specification, "hetero" means an atom selected from the group consisting of N, O, S, and P unless otherwise defined.

In the present specification, the term "alkyl group" is a "saturated alkyl group" that does not contain any alkenyl group or alkynyl group, unless otherwise defined; Or it means including all of the "unsaturated alkyl group" including at least one alkenyl group or an alkynyl group. The "alkenyl group" refers to a substituent in which at least two carbon atoms form at least one carbon-carbon double bond, and the "alkyne group" refers to a substituent in which at least two carbon atoms form at least one carbon-carbon triple bond. it means. The alkyl group may be branched, straight or cyclic.

The alkyl group may be a C1 to C20 alkyl group, and specifically, a C1 to C6 lower alkyl group, a C7 to C10 intermediate alkyl group, and a C11 to C20 higher alkyl group.

For example, a C1 to C4 alkyl group means the presence of 1 to 4 carbon atoms in the alkyl chain, which is methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and t-butyl. It indicates that it is selected from the group consisting of.

Typical alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, ethenyl group, propenyl group, butenyl group, cyclopropyl group, cyclobutyl group, cyclo And a pentyl group and a cyclohexyl group.

"Aromatic group" means a substituent in which all elements of a cyclic substituent have a p-orbital, and these p-orbitals form a conjugation. Specific examples include an aryl group and a heteroaryl group.

"Aryl group" includes a single ring or a fused ring, ie, a plurality of ring substituents that share adjacent pairs of carbon atoms.

"Heteroaryl group" means an aryl group in which a hetero atom selected from the group consisting of N, O, S, and P is included in the aryl group. When the heteroaryl group is a fused ring, each ring may contain 1 to 3 hetero atoms.

Unless otherwise defined herein, an alkyl group, cycloalkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, or aminoalkyl group is a substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl group, alkynyl group, It means an aryl group, a heteroaryl group, an alkoxy group, or an aminoalkyl group.

Unless otherwise defined in the specification, a divalent linking group refers to 1 selected from an alkylene group, an alkenylene group, an arylene group, -NR'-, -O-, -SO ₂ -, -CO-, -CF _2- It means a divalent linking group of more than a species. R'is an alkyl group.

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.

Insulation coating composition for electrical steel sheet

The insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by the following Formula 1 and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

The insulating coating composition according to an embodiment of the present invention includes a silane compound having a unique chemical structure in order to significantly improve the stress relief annealing heat resistance and corrosion resistance. In addition, when the silane compound is used alone, there is a problem that the film is peeled off during the stress relief annealing process and it is difficult to uniformly apply it to the surface of the electrical steel sheet. It also includes metal hydroxides to improve this.

Hereinafter, an insulating coating composition for an electrical steel sheet according to an embodiment of the present invention will be described in detail for each component.

First, the insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by Formula 1 on a solid basis. Specifically, it may contain 30 to 75 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

The silane compound represented by Formula 1 contains an Si element and a carbonyl group in the compound, so it has excellent heat resistance. In addition, the carbonyl group is excellent in reactivity with metal hydroxide, and thus plays an important role in forming a silane compound-metal hydroxide complex and remarkably improving the surface quality.

Specifically, the silane compound may be represented by the following formula (2).

[Formula 2]

(In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly It is a bond or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

Specifically, in Formulas 1 and 2, R ¹ and R ² may be hydrogen or an alkyl group. More specifically, R ¹ and R ² may be a methyl group or an ethyl group.

Specifically, in Formula 1, L may be at least one divalent linking group selected from an alkylene group, -O-, and -CO-. More specifically, in Formula 1, L may be represented by -L ¹ -O-, and L ¹ may be a direct bond or at least one divalent linking group selected from an alkylene group, -O-, and -CO-.

Silane compounds include triacetoxy(methyl)silane, triacetoxy(vinyl)silane, and dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di(methacroyloxy-1- ethoxy) silane) and 3- (trimethoxysilyl) propyl methacrylate (3- (trimethoxysilyl) propylmethacrylate) may be included.

If too little of the silane compound is included, heat resistance may be lowered, resulting in heat loss after stress relief annealing. If too much of the silane compound is included, the metal hydroxide is relatively small, and the film may be peeled off. Therefore, a silane compound may be included in the above-described range. More specifically, the silane compound may be included in an amount of 40 to 55 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

The insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a metal hydroxide. Specifically, it contains 25 to 70 parts by weight of metal hydroxide based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

Metal hydroxide is characterized by being well dispersed in a solvent, and plays a role in changing the surface property from hydrophobic to hydrophilic so that it can be well dispersed in the solvent through a chemical reaction with the functional group of the silane compound. Since this metal hydroxide is uniformly applied to the surface of the electrical steel sheet, it is of great help in remarkably improving heat resistance and corrosion resistance during stress relief annealing of the insulating film.

The metal hydroxide can be used without limitation as long as it is a metal containing a hydroxyl group (-OH). Specifically, the metal hydroxide is Ni(OH) ₂ , Co(OH) ₂ , Cu(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , Pd(OH) ₂ , In(OH) ₃ , (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ , Bi(OH) ₃ and Sn(OH) ₂ It may contain one or more of. More specifically, it may include at least one of Co(OH) ₂ and (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ .

If too little metal hydroxide is included, a problem may occur in dispersion of the silane compound, and uniform coating may be difficult. When too much metal hydroxide is included, the silane compound is relatively small, so that improvement of heat resistance and corrosion resistance during stress relief annealing may be insufficient. More specifically, 45 to 60 parts by weight of metal hydroxide may be included based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

The insulating coating composition for an electrical steel sheet according to an embodiment of the present invention may further include a metal nitride in addition to a silane compound and a metal hydroxide. When an appropriate amount of metal nitride is further included, the insulating properties and thermal conductivity properties of the formed insulating film may be further improved.

When a metal nitride is further included, 0.1 to 40% by weight of a metal nitride, 25 to 75% by weight of a silane compound, and 0.5 to 60% by weight of a metal hydroxide may be included, based on the solid content.

The solid content means that the solid portion excluding volatile components such as solvents in the insulating coating composition is based on 100% by weight.

If too little metal nitride is added, the effect of improving the insulating properties and the thermal conductivity properties may be insufficient. If too much metal nitride is included, the amount of the silane compound and the metal hydroxide are relatively small, and thus, improvement in heat resistance and corrosion resistance during stress relief annealing may be insufficient. More specifically, based on solid content, 1 to 25% by weight of a metal nitride, 35 to 65% by weight of a silane compound, and 15 to 50% by weight of a metal hydroxide may be included.

The metal nitride may include one or more of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

The average particle diameter of the metal nitride may be 0.05 to 20 μm. When the particle size of the metal nitride is appropriate, dispersibility and coating property are easy.

Insulation coating composition for electrical steel sheet according to an embodiment of the present invention is at least one of ethylene glycol (Ethylene golycol), propylene glycol (Propylene glycol), glycerin (Glycerine), butyl carbitol (Butyl carbitol) in addition to the silane compound and metal nitride. It may further include. By further including the above-described additives, it is possible to form an insulating film having excellent surface gloss and very beautiful roughness. The aforementioned additive may be further included in 1 to 15 parts by weight based on 100 parts by weight of the total amount of the silane compound and metal hydroxide. If too little of the additive is included, the above-described enhancement effect may be insufficient. Even if the additive is further included, there is no further improvement effect, and the dispersibility may be inferior. More specifically, the additive may be included in 3 to 10 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

The insulating coating composition may further contain a solvent for even dispersion and easy application of solids. Water, alcohol, etc. may be used as the solvent, and may include 300 to 1000 parts by weight based on 100 parts by weight of the total amount of the silane compound and metal hydroxide. As such, the insulating coating composition may be in the form of a slurry.

Electric steel plate

The electrical steel sheet 100 according to an embodiment of the present invention includes an electrical steel sheet substrate 10 and an insulating film 20 located on one or both sides of the electrical steel sheet substrate 10. 1 shows a schematic side cross-sectional view of an electrical steel sheet according to an embodiment of the present invention. 1 shows a case where an insulating film 20 is formed on the upper surface of the electrical steel plate substrate 10.

The insulating film 20 includes a silane compound and a metal hydroxide represented by Formula 1 below.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.)

The insulating film 20 of the electrical steel sheet 100 according to an embodiment of the present invention includes a silane compound having a unique chemical structure in order to significantly improve the stress relief annealing heat resistance and corrosion resistance, and also improve thermal conductivity. In addition, when the silane compound is used alone, there is a problem that the film is peeled off during the stress relief annealing process and it is difficult to uniformly apply it to the surface of the electrical steel sheet. It also includes metal hydroxides to improve this.

Since the content of the components of the insulating film 20 has been described in detail with respect to the above-described insulating film composition, redundant descriptions will be omitted. In the process of forming the insulating film 20, the chemical structure of some silane compounds may be modified, but most of the silane compounds retain their chemical structure. In addition, in the process of forming the insulating film 20, a silane compound and a metal hydroxide may react to form a compound. In this case, the ratio of the silane compound and the content of metal hydroxide in the compound are calculated, and the silane compound and the metal hydroxide are respectively It is calculated by the weight of Since volatile components such as a solvent are removed during the formation of the insulating film 20, the components in the insulating film 20 are substantially the same as the solid component in the insulating film composition.

The insulating film 20 may contain 0.1 to 50% by weight of Si. In this case, Si may be Si in the silane compound, Si in the metal nitride when Si ₃ N ₄ is used as the metal nitride, or Si diffused from the electrical steel sheet substrate 10. Si is included in an appropriate amount, so that the insulating properties of the insulating film 20 can be secured.

In addition to Si, the insulating film 20 may include an insulating film composition such as Fe, C, and O, and an element derived from the electrical steel plate substrate 10.

The thickness of the insulating film 20 may be 0.1 to 10 μm. If the thickness of the insulating film 20 is too thin, heat resistance may be lowered, resulting in a problem of heat loss after stress relief annealing. If the thickness of the insulating film 20 is too thick, a drop ratio may be lowered, resulting in a problem of deteriorating motor characteristics. Accordingly, the thickness of the insulating film 20 can be adjusted within the above-described range. More specifically, the thickness of the insulating film 20 may be 0.2 to 5 μm.

The electrical steel plate substrate 10 may be used without limitation of a non-oriented electrical steel sheet or a grain-oriented electrical steel sheet. Specifically, a non-oriented electrical steel sheet can be used. In one embodiment of the present invention, insulating properties are generated by the components of the insulating film 20, and may be irrelevant to the alloy component of the electrical steel sheet. Hereinafter, as an example, an alloy component of the electrical steel sheet will be described.

Electrical steel sheet C: 0.01% by weight or less, Si: 6.0% by weight or less, P: 0.5% by weight or less, S: 0.005% by weight or less, Mn: 0.1 to 1.0% by weight, Al: 0.40 to 2.0% by weight, N: 0.005 Wt% or less, Ti: 0.005 wt% or less, and Sb, Sn, Ni or a combination thereof: 0.01 to 0.15 wt%, and may include Fe and unavoidable impurities as the balance.

Hereinafter, it will be described in detail for each alloy component.

Hereinafter, the reasons for limiting the components of the non-oriented electrical steel sheet substrate 10 will be described.

C: 0.01% by weight or less

Carbon (C) is a component that is not very helpful in improving the magnetic properties of the electrical steel sheet in the embodiment according to the present invention, so it is preferable to remove it as much as possible. C is contained in less than 0.01% by weight as it causes magnetic aging in the final product and degrades magnetic properties during use, and it is more preferable to limit it to less than 0.005% by weight in the final product because the lower the content of C is, the more desirable it is for magnetic properties. Do.

Si: 6.0% by weight or less

Silicon (Si) is a component that decreases eddy current loss during iron loss by increasing the specific resistance of steel, and when the content of Si is too large, brittleness increases and cold rolling becomes difficult. Therefore, it is preferable to limit it to 6.0% by weight or less. More specifically, Si may be included in an amount of 0.1 to 4.0% by weight.

P: 0.5% by weight or less

Phosphorus (P) is added to increase the specific resistance and improve the texture to improve magnetism. If it is added excessively, it is preferable to limit it to 0.5% by weight or less because cold rolling property deteriorates.

S: 0.005% by weight or less

Since sulfur (S) forms fine precipitates of MnS and CuS and deteriorates magnetic properties by suppressing crystal grain growth, it is preferable to manage as low as possible, and the content thereof is limited to 0.005% by weight or less.

Mn: 0.1 to 1.0% by weight

If manganese (Mn) is present in an amount of less than 0.1% by weight, fine MnS precipitates are formed, thereby inhibiting grain growth, thereby deteriorating magnetism. Therefore, when present in an amount of 0.1% by weight or more, coarse MnS is formed, and the S component can be prevented from being precipitated as a finer precipitate, CuS. However, since the magnetism deteriorates when Mn is increased, it is added at 1.0% by weight or less.

Al: 0.40 to 2.0% by weight

Al is an effective component in reducing eddy current loss by increasing specific resistance. If the amount is less than 0.40% by weight, AlN is finely precipitated, resulting in poor magnetism, and if it exceeds 2.0% by weight, the workability is deteriorated.

N: 0.005% by weight or less

N is contained in a small amount because it suppresses grain growth by forming fine and long AlN precipitates inside the base material, and is preferably limited to 0.005% by weight or less.

Ti: 0.005% by weight or less

Ti forms fine precipitates of TiN and TiC to suppress crystal grain growth, and when added in excess of 0.005% by weight, many fine precipitates are generated, deteriorating the texture and deteriorating magnetism.

Sb, Sn, Ni or a combination thereof: 0.01 to 0.15% by weight

Sb, Sn, or Ni is a surface precipitation element that is concentrated on the surface layer of the steel plate to suppress the adsorption of nitrogen and, as a result, does not interfere with the growth of crystal grains, thereby lowering the iron loss, and adding Sb, Sn, or Ni alone or in combination If one content is too small, there may be a problem that the effect is reduced. If the amount of Sb, Sn, or Ni added alone or in combination is too large, grain boundary segregation occurs severely, resulting in increased brittleness of the steel sheet, which may lead to sheet fracture during rolling. When two or more types of Sb, Sn, and Ni are added in combination, the total amount may be 0.01 to 0.15% by weight.

More specifically, 0.01 to 0.05% by weight of Sb, 0.01 to 0.12% by weight of Sn, and 0.01 to 0.06% by weight of Ni may be included.

As described above, the electrical steel sheet according to an embodiment of the present invention has excellent thermal conductivity due to the formation of an insulating film. Specifically, the following general formula 1 may be satisfied.

[General Formula 1]

20≤ TC ≤ 200 W/mK

(In the general formula 1, TC denotes a thermal conductivity value measured by induction heating a 600x400mm specimen at 230°C and using a PPMS (Physical Property Measurement System).)

Manufacturing method of electrical steel sheet

2 schematically shows a flow chart of a method for manufacturing an electrical steel sheet according to an embodiment of the present invention. The flow chart of the manufacturing method of the electrical steel sheet of FIG. 2 is for illustrative purposes only, and the present invention is not limited thereto. Therefore, the manufacturing method of the electrical steel sheet can be variously modified.

As shown in Figure 2, the method of manufacturing an electrical steel sheet comprises the steps of manufacturing an electrical steel sheet substrate (S10); And forming an insulating film by applying an insulating film composition to one or both surfaces of an electrical steel substrate (S20). In addition, the manufacturing method of the electrical steel sheet may further include other steps.

First, in step S10, an electrical steel plate substrate is prepared. Since the alloy components of the electrical steel sheet have been described in detail, repeated descriptions are omitted.

The step of manufacturing the electrical steel sheet base material comprises the steps of hot rolling the slab to manufacture a hot rolled sheet; Cold-rolling the hot-rolled sheet to manufacture a cold-rolled sheet, and final annealing the cold-rolled sheet may be included.

First, the slab is heated. At this time, the slab heating can be heated below 1,200 ℃.

Next, the heated slab is hot-rolled to manufacture a hot-rolled sheet. The manufactured hot-rolled sheet can be hot-rolled and annealed.

Next, the hot-rolled sheet is cold-rolled to manufacture a cold-rolled sheet. Cold rolling may be performed once, or two or more cold rolling including intermediate annealing may be performed.

Next, the cold-rolled sheet is finally annealed. At this time, in the final annealing step of the cold-rolled sheet, the rolling oil present in the cold-rolled sheet is degreased, primary annealing is performed, and secondary annealing in an atmosphere composed of hydrogen and nitrogen may be performed. In addition, in the final annealing, the dew point temperature may be controlled to be -5°C or less for the purpose of preventing magnetism from deteriorating due to oxide formation on the surface.

Returning to the description of the manufacturing method of the electrical steel sheet, next step (S20) is to form an insulating film by applying the insulating film composition to one or both surfaces of the electrical steel sheet substrate. Since the insulating coating composition is the same as described above, a duplicate description will be omitted.

The step of forming the insulating film may include heat-treating the steel sheet coated with the insulating film composition at a temperature of 100 to 680°C. If the heat treatment temperature is too low, it is difficult to remove the solvent, and it is difficult to form a beautiful insulating film. If the heat treatment temperature is too high, a problem of poor adhesion may occur. More specifically, it may be heat-treated at a temperature of 350 to 650°C. The heat treatment time may be 5 to 200 seconds.

After the step of forming the insulating film, it may further include a step of stress relief annealing at a temperature of 700 to 1000 ℃. In one embodiment of the present invention, even after stress relief annealing by the silane compound and metal hydroxide in the insulating film composition, it is possible to maintain excellent adhesion and surface properties of the insulating film. If the temperature of the stress relief annealing is too low, the desired stress relief may not be performed smoothly. If the temperature of the stress relief annealing is too high, the magnetism of the electrical steel sheet may be inferior.

The step of stress relief annealing may be performed in a nitrogen atmosphere, and may be performed for 1 to 5 hours.

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

Experimental Example 1: Characteristics of each type of silane compound

Example 1

3.4 wt% silicon (Si), aluminum (Al): 0.80 wt%, manganese (Mn): 0.17 wt% titanium (Ti): 0.0015 wt%, tin (Sn): 0.03 wt%, nickel (Ni): 0.01 % By weight, carbon (C): 0.003% by weight, nitrogen (N): 0.0013% by weight, phosphorus (P): 0.012% by weight, sulfur (S): 0.001% by weight, the balance consisting of Fe and other inevitable impurities The slabs were prepared.

The slab was heated at 1130° C. and then hot-rolled to a thickness of 2.3 mm to prepare a hot-rolled sheet.

The hot-rolled sheet was wound at 650°C, cooled in air, and then annealed at 1040°C for 2 minutes, quenched in water, pickled, and then cold-rolled to a thickness of 0.35mm to prepare a cold-rolled sheet.

The cold-rolled sheet was subjected to final annealing by controlling the dew point temperature in an atmosphere of 20% hydrogen and 80% nitrogen at 1040°C for 50 seconds, thereby producing an annealed steel sheet.

As an insulating coating composition, triacetoxymethylsilane 60 parts by weight, nickel hydroxide (Ni(OH) ₂ ) 20 parts by weight, strontium hydroxide (Sr(OH) ₂ ) 10 parts by weight, boron nitride 5 parts by weight, and ethylene glycol 5 parts by weight The mixture was mixed with distilled water to prepare a slurry form, and the slurry was applied to the final annealed steel sheet using a roll, and then heat-treated at 650°C for 30 seconds and cooled in air. The electrical steel sheet was subjected to stress relief annealing (SRA, Stress Relief Annealing) for 2 hours at 750°C in a 100% nitrogen atmosphere and cooled in air. The thickness of the insulating film was about 0.8 µm.

Examples 2 to 12

In the same manner as in Example 1, the contents and types of the silane compound, metal hydroxide, and metal nitride in the insulating film composition were replaced as shown in Table 1 below to form an insulating film.

Comparative Example 1

In the same manner as in Example 1, but without metal hydroxide, an insulating coating composition containing 100 parts by weight of triacetoxymethylsilane was used.

Comparative Example 2

In the same manner as in Example 1, but without a silane compound, an insulating coating composition containing 100 parts by weight of chromium hydroxide was used.

Comparative Example 3

In the same manner as in Example 1, an insulating coating composition containing 60 parts by weight of chromium hydroxide and 40 parts by weight of boron nitride was used without a silane compound.

The properties of the electrical steel sheets prepared in Examples and Comparative Examples were measured and summarized in Table 2 below.

The iron loss (W _15/50 ) refers to the power loss that occurs when a magnetic field with a frequency of 50 Hz is magnetized to 1.5 Tesla by alternating current.

In addition, the insulating properties were measured on the upper part of the insulating film using a Franklin measuring device according to ASTM A717 international standard.

In addition, the adhesion is expressed as the minimum arc diameter without film peeling when the specimen is bent 180° in contact with a 10 to 100 mm arc.

In addition, the surface feature is the result of visually evaluating the degree of uniformity of color and formation of a uniform film.

In addition, thermal conductivity was measured by induction heating the electrical steel sheet at 230°C and the thermal conductivity of the specimen by PPMS (Physical property measurement system, manufactured by Quantum Design).

division Silane compound
(Part by weight) Metal hydroxide
(Part by weight) Metal nitride
(Part by weight) Comparative Example 1 A(100) - - Comparative Example 2 - Cr(100) - Comparative Example 3 - Cr(60) BN (40) Comparative Example 4 A(10) Cr(90) Example 1 A(60) Ni(20), Sr(10) BN(5) Example 2 B(50) Cr(30) AlN(10) Example 3 C(70) Co(20) AlN (7) Example 4 D(33) Cr(50) Si ₃ N ₄ (10) Example 5 A(30), B(25) Cu(17), Cr(23) Mg ₃ N ₂ (4) Example 6 A(35), C(10), D(5) Cr(17), Pd(3) Ca ₃ N ₂ (10) Example 7 B(45) Cr(40) Sr ₃ N ₂ (7) Example 8 B(30) Cr(20), Co(5), Ni(5) Ba ₃ N ₂ (35) Example 9 C(48) Cr(35), Ba(5) Ge ₃ N ₄ (0.5) Example 10 A(10), B(10), C(10), D(15) Cr(30), Co(0.5), Bi(0.1), Sn(0.1) Ge ₃ N ₄₃ (5) Example 11 B(45) Cr(30), Co(0.5), Bi(0.1), Sn(0.1) BN (15), AlN (5) Example 12 C(5), B(35) Cr(25), In(0.5), Sn(0.2) BN (20), AlN (5) Silane compound
A: triacetoxymethylsilane
B: triacetoxyvinylsilane
C: dimethyldimethacroyloxy-1-ethoxysilane
D: 3-(trimethoxysilyl)propyl methacrylate
Metal hydroxide
Cr: (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂
Ni: Ni(OH) ₂
Sr: Sr(OH) ₂
Co: Co(OH) ₂
Pd: Pd(OH) ₂
Ba: Ba(OH) ₂
Bi: Bi(OH) ₃
Sn: Sn(OH) ₂
In: In(OH) ₃

division _Iron loss (W _15/50 , W/Kg) Insulation (mA) Adhesion (mmφ) Surface features Thermal conductivity (W/mK) Comparative Example 1 3.12 990 70 Extreme surface peeling 15 Comparative Example 2 3.55 990 70 Extreme surface peeling 4 Comparative Example 3 3.04 990 70 Extreme surface peeling 17 Comparative Example 4 3.20 985 70 Extreme surface peeling 9 Example 1 2.45 782 10 Uniform 78 Example 2 2.34 777 10 Uniform 26 Example 3 2.38 812 10 Uniform 22 Example 4 2.27 650 10 Uniform 28 Example 5 2.01 711 10 Uniform 31 Example 6 2.10 750 10 Uniform 26 Example 7 2.37 688 10 Uniform 47 Example 8 1.88 745 15 Uniform 75 Example 9 2.15 811 10 Uniform 32 Example 10 1.90 527 15 Uniform 31 Example 11 2.11 450 15 Uniform 142 Example 12 2.05 475 20 Uniform 170

As shown in Tables 1 and 2, it can be seen that the insulating film properties of the examples are superior to those of the comparative examples. In addition, when a silane compound or a metal hydroxide is included alone, it can be confirmed that film peeling occurs severely and the magnetic properties are deteriorated.

3 and 4 show a scanning electron microscope (SEM) photograph of a cross section of an electrical steel sheet prepared in Example 2 and Comparative Example 2, respectively. As shown in FIG. 3, in the case of Example 2, it can be seen that the beautiful insulating film is maintained even after the SRA. On the other hand, as shown in FIG. 4, in the case of Comparative Example 2, it can be seen that a number of cracks occur on the surface of the insulating film after SRA.

5 shows the results of FT-IR-RAS analysis of the electrical steel sheet film prepared in Example 2. As can be seen in FIG. 5, it can be seen that triacetoxyvinylsilane is present in the film.

Experimental Example 2: Evaluation of dot ratio

Example 13

Silicon (Si) 4.2 wt%, Aluminum (Al): 0.80 wt%, Manganese (Mn): 0.15 wt% Titanium (Ti) 0.001 wt%, Tin (Sn) 0.08 wt%, Carbon (C) 0.004 Slabs were prepared containing 0.0015% by weight of nitrogen (N), 0.015% by weight of phosphorus (P), and 0.001% by weight of sulfur (S), the balance being Fe and other inevitable impurities.

The slab was heated at 1150° C. and then hot-rolled to a thickness of 2.3 mm to prepare a hot-rolled sheet.

The hot-rolled sheet was wound at 650°C, cooled in air, and then annealed at 1040°C for 3 minutes, quenched in water, pickled, and then cold-rolled to a thickness of 0.35mm to prepare a cold-rolled sheet.

The cold-rolled sheet was adjusted to a dew point temperature of -40°C in an atmosphere of 30% hydrogen and 70% nitrogen for 60 seconds at 1050°C, and final annealing was performed to prepare an annealed steel sheet.

Thereafter, as an insulating coating composition, triacetoxymethylsilane 25 parts by weight, triacetoxyvinylsilane 25 parts by weight, chromium hydroxide ((CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ ) 15 parts by weight, cobalt hydroxide (Co (OH) ₂ ) 15 parts by weight, strontium hydroxide (Sr(OH) ₂ ) 3 parts by weight, boron nitride 15 parts by weight, and propylene glycol 2 parts by weight are mixed with distilled water to prepare a slurry form, and the slurry is thickened using a roll. After coating with, it was heat-treated at 650°C for 30 seconds and cooled in air. The electrical steel sheet was subjected to stress relief annealing (SRA, Stress Relief Annealing) heat treatment at 820°C for 2 hours in a 100% nitrogen atmosphere, and then cooled in air. Table 3 shows the results of evaluating the degree of rust generation on the surface after the stress-relieving annealed steel sheet was treated at 60° C. and 95% humidity for 24 hours.

Comparative Example 5

After slowly adding about 7 parts by weight of MgO and CaO to the ionized water, about 20 parts by weight of CrO ₃ causing an exothermic reaction was slowly injected into the solution (MgO, CaO + ionized water), followed by stirring until it became a transparent brown liquid, followed by branding. .

Thereafter, about 30 parts by weight of one type of acrylic resin or acrylic-styrene copolymer resin and 6.7 parts by weight of butyl carbitol as a reducing agent were injected into the solution to prepare an insulating coating composition.

In the same manner as in Example 13, an insulating film was formed using the prepared insulating film composition.

Comparative Example 6

Aluminum 1 phosphate (Al(H ₂ PO ₄ ) ₃ ) 50 parts by weight, Zinc 1 phosphate (Zn(H ₂ PO ₄ ) ₂ ) 50 parts by weight, 210 parts by weight of epoxy resin, cobalt hydroxide An insulating coating composition containing 1 part by weight, 1 part by weight of strontium hydroxide, and 0.05 part by weight of a Ti chelating agent was used.

In the same manner as in Example 13, an insulating film was formed using the insulating film composition.

division _Iron loss (W _15/50 , W/Kg) Drop rate (%) Area of rust (%) Example 13 1.87 99.2 0.6 Comparative Example 5 2.87 96.5 54.2 Comparative Example 6 2.57 97.2 32.7

As shown in Table 3, compared to Comparative Examples 5 and 6, it can be seen that the characteristics of Example 13 are significantly superior.

The present invention is not limited to the embodiments, but may be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains may use other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it can be implemented. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

100: electrical steel sheet
10: electrical steel plate base
20: insulating film

Claims (13)

Electrical steel substrate and
Including an insulating film located on one or both sides of the electrical steel substrate,
The insulating film contains a silane compound, a metal nitride and a metal hydroxide represented by the following formula (1),
Electrical steel sheet comprising 0.1 to 40% by weight of the metal nitride, 25 to 75% by weight of the silane compound, and 0.5 to 60% by weight of the metal hydroxide.
[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.) The method of claim 1,
The silane compound is an electrical steel sheet represented by the following formula (2).
[Formula 2]

(In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly It is a bond or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.) The method of claim 1,
The silane compound is triacetoxy(methyl)silane, triacetoxy(vinyl)silane, dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di(methacroyloxy-1). -ethoxy) silane) and 3- (trimethoxysilyl) propyl methacrylate (3- (trimethoxysilyl) propylmethacrylate) an electrical steel sheet containing at least one of. The method of claim 1,
The metal hydroxide is Ni(OH) ₂ , Co(OH) ₂ , Cu(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , Pd(OH) ₂ , In(OH) ₃ , (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ , Bi(OH) ₃ and Sn(OH) ₂ An electrical steel sheet containing at least one of. delete The method of claim 1,
The metal nitride is an electrical steel sheet comprising at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ . The method of claim 1,
The electrical steel sheet is an electrical steel sheet that satisfies the following General Formula 1.
[General Formula 1]
20≤ TC ≤ 200 W/mK
(In the general formula 1, TC represents a thermal conductivity value measured by induction heating a 600×400mm specimen at 230° C. and PPMS (Physical Property Measurement System).) The method of claim 1,
The electrical steel sheet substrate is C: 0.01 wt% or less, Si: 6.0 wt% or less, P: 0.5 wt% or less, S: 0.005 wt% or less, Mn: 0.1 to 1.0 wt%, Al: 0.40 to 2.0 wt%, N : 0.005% by weight or less, Ti: 0.005% by weight or less and Sb, Sn, Ni, or a combination thereof: an electrical steel sheet containing 0.01 to 0.15% by weight, and Fe and inevitable impurities as the balance. Including a silane compound represented by the following Formula 1, a metal nitride and a metal hydroxide,
An insulating coating composition for an electrical steel sheet comprising 0.1 to 40% by weight of a metal nitride, 25 to 75% by weight of a silane compound, and 0.5 to 60% by weight of a metal hydroxide based on solid content.
[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.) delete The method of claim 9,
The metal nitride is an insulating coating composition for an electrical steel sheet comprising at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ . Preparing a hot-rolled sheet by hot-rolling the slab, undergoing cold-rolling, and then preparing a final annealing-completed steel sheet; And
Including the step of forming an insulating film by applying an insulating film composition to the steel plate,
The insulating coating composition contains a silane compound, a metal nitride and a metal hydroxide represented by the following formula (1),
A method of manufacturing an electrical steel sheet comprising 0.1 to 40% by weight of the metal nitride, 25 to 75% by weight of the silane compound, and 0.5 to 60% by weight of the metal hydroxide.
[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer of 1 to 4, and n is 4-m.) The method of claim 12,
The electrical steel sheet on which the insulating film is formed is a method of manufacturing an electrical steel sheet that satisfies the following General Formula 1.
[General Formula 1]
20≤ TC ≤ 200 W/mK
(In the general formula 1, TC denotes a thermal conductivity value measured by induction heating a 600x400mm specimen at 230°C and using a PPMS (Physical Property Measurement System).)

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