KR20200013469A - Insulating coating composition for electrical steel sheet and electrical steel sheet comprising insulating coating - Google Patents

Abstract

According to one embodiment of the present invention, an insulation film composition for an electric steel plate includes: a silane compound described in the chemical formula 1 below; and at least one kind of chromic acid among a chromic anhydride, a chromate and a dichromate. In the chemical formula 1: R^1 is hydrogen, a halogen element, a straight-chain or branch type alkyl group, a cyclo-alkyl group, an alkenyl group, an alkynyl group, an aryl group, a hetero-aryl group, and an alkoxy group or an amino-alkyl group; L is a directly coupled or bivalent connection groups; m is an integer from 1 to 4; and n is 4-m.

Description

INSULATING COATING COMPOSITION FOR ELECTRICAL STEEL SHEET AND ELECTRICAL STEEL SHEET COMPRISING INSULATING COATING}

The present invention relates to an electrical steel sheet comprising an insulating coating composition for electrical steel sheet and an insulating coating. More specifically, the present invention relates to an electrical steel sheet including an insulating coating composition and an insulating coating for an electrical steel sheet having excellent heat resistance 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, a transformer, etc. requires not only an interlayer resistance but various characteristics. For example, it is convenience in work forming, storage, stability in use, etc. Moreover, since electrical steel sheets are used for various uses, development of various insulating films is performed according to the use.

For example, when the electrical steel sheet is subjected to punching, shearing, bending, or the like, magnetic properties deteriorate due to residual deformation. Therefore, stress relief annealing (SRA) is sometimes performed at high temperature to recover the deteriorated magnetic properties. Therefore, the insulating film needs heat resistance that does not peel off during stress relief annealing and maintains intrinsic electrical insulation.

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

In addition, a method of improving adhesion during stress relief annealing 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 characteristics of phosphate having high absorption resistance, so that dust is generated during processing of the product, and heat resistance is rather inferior to a portion where whitening defects occur.

Provided is an electrical steel sheet comprising an insulating coating composition for electrical steel sheet and an insulating coating. More specifically, by using a silane compound containing a specific chemical structure, to provide an electrical steel sheet comprising an insulating coating composition and an insulating film for electrical steel sheet excellent in heat resistance during stress relief annealing.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention is a silane compound represented by the formula (1) silane compound; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.)

The total amount of the silane compound and the chromic acid compound may include 10 to 80 parts by weight of the silane compound and 20 to 90 parts by weight of the chromic acid compound.

In formula 1 R ¹ can be hydrogen, a halogen atom, a straight-chain or branched alkyl group or alkoxy group.

In Formula 1, L may be at least one of a direct bond, an alkylene group, and —CF ₂ —.

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

[Formula 2]

R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, 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 a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

R ² and R ³ in Formula 2 may each independently be a hydrogen or a halogen element.

The silane compounds are triethyl (trifluoromethyl) silane (triethyl), trimethoxy (trifluoropropyl) silane (trimethoxypropyl) silane, Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-methyl) (Trifluopropyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl-triethoxysilane).

The total amount of the silane compound and the chromic acid compound may further include 0.5 to 65 parts by weight of the ceramic powder.

Ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, ZrO 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O 3 , BN, CrN, BaTiO ₃ , SiC, and TiC.

The average particle diameter of the ceramic powder may be 0.05 to 20 μm.

Acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin, polyamide resin, polycarbonate resin, phenol resin, alkyd resin, based on 100 parts by weight of the silane compound and the chromic acid compound. And 0.5 to 30 parts by weight of one or more polymer resins in the epoxy resin.

1 to 15 parts by weight of one or more of ethylene glycol, propylene glycol, glycerine, and butyl carbitol based on 100 parts by weight of the silane compound and the chromic acid compound It may include.

An 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.

The insulating film is a silane compound represented by the following formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.)

The insulating film contains 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F.

The thickness of the insulating coating may be 0.1 to 10㎛.

Method for producing an electrical steel sheet according to an embodiment of the present invention comprises the steps of preparing an electrical steel sheet; And forming an insulating coating by applying the insulating coating composition to one or both surfaces of the electrical steel sheet substrate.

The insulation coating composition may include an silane compound represented by Formula 1 below; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.)

The manufacturing of the electrical steel sheet may include hot rolling the slab to prepare a hot rolled sheet; Cold rolling of the hot rolled sheet may include producing a cold rolled sheet and the final annealing of the cold rolled sheet.

The forming of the insulating film may include heat treating the steel sheet to which the insulating film composition is applied at a temperature of 100 to 680 ° C.

After forming the insulating film, it may further include the step of stress relief annealing at a temperature of 700 to 1000 ℃.

According to one embodiment of the present invention, it is possible to obtain an electrical steel sheet having excellent iron loss characteristics after the insulation film is formed.

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

According to one embodiment of the present invention, even after stress relief annealing (SRA), it is possible to obtain an insulating film excellent in roughness, adhesion and peeling resistance.

1 is a schematic diagram of a cross section of an electrical steel sheet according to an embodiment of the present invention.
2 is a flowchart of a method of manufacturing an electrical steel sheet according to an embodiment of the present invention.
Figure 3 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 2.
4 is a scanning electron microscope (SEM) photograph of the surface of the electrical steel sheet prepared in Comparative Example 3.

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

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular property, region, integer, step, operation, element, and / or component, and the presence of another property, region, integer, step, operation, element, and / or component, or It does not exclude the addition.

When a portion is referred to as being "on" or "on" another portion, it may be directly on or on the other portion or may be accompanied by another portion therebetween. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted as ideal or very formal meaning unless defined.

In the description of group (atom group) in this specification, the description which is not describing substitution and unsubstitution includes what has a substituent with the thing which does not have a substituent. For example, an "alkyl group" includes not only the alkyl group (unsubstituted alkyl group) which does not have a substituent but the alkyl group (substituted alkyl group) which has a substituent.

As used herein, unless otherwise defined, at least one hydrogen in the compound 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 groups; Amine groups; Alkylamine group; Arylamine group; Mean substituted by ethyleneoxyl group or halogen group.

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

As used herein, unless otherwise defined, an "alkyl group" means a "saturated alkyl group" that does not include any alkenyl or alkynyl groups; Or "unsaturated alkyl group" containing at least one alkenyl group or 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 "alkyn 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 chain or cyclic.

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

For example, a C1 to C4 alkyl group means that there are 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 Selected from the group consisting of:

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

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

An "aryl group" includes a single ring or fused ring, ie, a plurality of ring substituents that divide adjacent pairs of carbon atoms.

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

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

Unless otherwise defined herein, a divalent linking group is 1 selected from an alkylene group, an alkenylene group, an arylene group, -NR'-, -O-, -SO _2- , -CO-, and -CF _2- It means two or more divalent linking groups. R 'is an alkyl group.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Insulation coating composition for electrical steel sheet

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention is a silane compound represented by the formula (1) silane compound; And at least one chromic acid compound selected from chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.)

Insulating coating composition according to an embodiment of the present invention includes a silane compound having a unique chemical structure 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 in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. It also includes chromic acid compounds to improve this.

Hereinafter, the insulating film composition for 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 Chemical Formula 1.

The silane compound represented by the formula (1) contains Si element and F element in the compound and is extremely excellent in heat resistance. In particular, the element F has an effect of suppressing a chemical reaction in which moisture in the air penetrates into the insulating film, and thus plays an important role in remarkably improving the surface quality of electrical steel sheet due to its excellent chemical resistance, insulation, and corrosion resistance.

The total amount of the silane compound and the chromic acid compound may include 10 to 80 parts by weight of the silane compound.

If too little silane compound is included, the content of Si and F elements in the insulating film to be formed decreases heat resistance, which may lead to heat loss after stress relief annealing. The compatibility with the solvent may be lowered, which may cause a problem of difficulty in forming a uniform insulating film. Therefore, the silane compound may be included in the aforementioned range. More specifically, the silane compound may be included from 40 to 70 parts by weight.

In formula 1 R ¹ can be hydrogen, a halogen atom, a straight-chain or branched alkyl group or alkoxy group. When m is 2 or more, a plurality of R ¹ may be the same or different from each other.

In Formula 1, L may be at least one of a direct bond, an alkylene group, and —CF ₂ —. When n is 2 or more, the plurality of L's may be the same or different from each other.

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

[Formula 2]

R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, 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 a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Specifically, in Formula 2, R ¹ , m, n are the same as the description of Formula 1.

L ₁ may be a direct bond or a divalent linking group. More specifically, L ₁ may be at least _one of a direct bond, an alkylene group, and —CF ₂ —.

R ² and R ³ may be each independently hydrogen or a halogen element.

The silane compounds are triethyl (trifluoromethyl) silane (triethyl), trimethoxy (trifluoropropyl) silane (trimethoxypropyl) silane, Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-methyl) (Trifluopropyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl-triethoxysilane).

More specifically, the silane compounds are triethyl (trifluoromethyl) silane, Trimethoxy (3,3,3-trifluoropropyl) silane, Dimethoxy-methyl (3,3,3-trifluoropropyl) silane and 1H, 1H, 2H, 2H-Perfluorooctyl-triethoxysilane It may include one or more of.

The insulating coating composition for electrical steel sheet according to one embodiment of the present invention includes at least one chromic acid compound selected from chromic anhydride, chromate and dichromate.

The chromic acid compound chemically reacts with the silane compound to improve dispersion stability to form a uniform film. In addition, the chromic acid compound has the advantage of reducing the cost in mass production and has the advantage that can be stably operated in the insulation coating process.

As chromate and dichromate, salts, such as Na, K, Mg, Ca, Mn, Mo, Zn, Al, can be used, for example.

The total amount of the silane compound and the chromic acid compound may include 20 to 90 parts by weight of the chromic acid compound. If too little chromic acid compound is included, problems may occur in dispersion of the silane compound, making it difficult to uniformly apply the chromic acid compound. When too much chromic acid compound is included, the silane compound may be relatively small, and thus the improvement of heat resistance and corrosion resistance during stress relief annealing may be insufficient. More specifically, the chromic acid compound may be included in 30 to 60 parts by weight.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention may further include a ceramic powder in addition to the silane compound and chromic acid compound. When the ceramic powder is further included in an appropriate amount, the insulating properties of the insulating film to be formed may be further improved.

The ceramic powder may be included in an amount of 0.5 to 65 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound. If too little ceramic powder is included, the effect of improving the insulating properties may be insufficient. If too much ceramic powder is included, the amount of the silane compound and the chromic acid compound may be relatively low, resulting in insufficient heat and corrosion resistance improvement during stress relief annealing. More specifically, the ceramic powder may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound.

Ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, ZrO 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O 3 , BN, CrN, BaTiO ₃ , SiC, and TiC. More specifically, the ceramic powder is MgO, CaO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ · TiO ₂ , Y ₂ O ₃ , 9Al ₂ O ₃ · B ₂ O ₃ , BN, May contain one or more of CrN, BaTiO ₃ , SiC, and TiC

The average particle diameter of the ceramic powder may be 0.05 to 20 μm. The particle diameter of the ceramic powder should be appropriate, so that dispersibility and applicability are easy.

Insulating coating composition for electrical steel sheet according to an embodiment of the present invention is based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound, acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin It may further comprise 0.5 to 30 parts by weight of at least one polymer resin of polyamide resin, polycarbonate resin, phenol resin, alkyd resin and epoxy resin. By adding an appropriate amount of the above-mentioned polymer resin further, it is possible to produce an electrical steel sheet excellent in surface gloss and very beautiful roughness.

Insulating coating composition for electrical steel sheet according to an embodiment of the present invention is based on 100 parts by weight of the silane compound and chromic acid compound, ethylene glycol (Ethylene golycol), propylene glycol (Glycerine), glycerine (butyl carbitol) Butyl carbitol) may further comprise 1 to 15 parts by weight of one or more. By further including the above-mentioned additives, it is possible to form an insulating film having excellent surface gloss and very beautiful roughness. If too little additive is included, the above-mentioned improvement effect may be insufficient. Even if the additive is further included, there is no further improving effect, but may be inferior in dispersibility. More specifically, the additive may be included in an amount of 3 to 10 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound.

The insulating coating composition may further include a solvent for even dispersion and easy application of the solids. Water, alcohol, or the like 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 the chromic acid compound. As such, the insulating coating composition may be in the form of a slurry.

Electrical steel sheet

The electrical steel sheet 100 according to the embodiment of the present invention includes an electrical steel sheet substrate 10 and an insulating coating 20 located on one or both surfaces of the electrical steel sheet substrate 10. 1 is a schematic side cross-sectional view of an electrical steel sheet according to an embodiment of the present invention. In FIG. 1, the insulating film 20 is formed on the upper surface of the electrical steel sheet substrate 10.

Insulating coating 20 of the electrical steel sheet 100 according to an embodiment of the present invention includes a silane compound having a unique chemical structure 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 in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. It also includes chromic acid compounds 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 thereof will be omitted. While the chemical structure of some silane compounds may be modified during the formation of the insulating film 20, most of the silane compounds retain their chemical structure. In addition, the silane compound and the chromic acid compound may react to form a compound in the process of forming the insulating film 20. In this case, the silane compound and the chromic acid compound may be calculated by calculating the ratio of the silane compound and the chromic acid compound in the compound, respectively. Calculate by weight. Since volatile components, such as a solvent, are removed in the formation process of the insulating film 20, the component in the insulating film 20 is substantially the same as the solid content component in an insulating film composition. Solid content means the thing based on 100 weight% of solid parts except volatile components, such as a solvent in an insulation coating composition.

The insulating film 20 may include 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F. In this case, Si may be Si in the silane compound, Si in the ceramic powder, or Si diffused from the electrical steel sheet substrate 10 when SiO ₂ is used as the ceramic powder. An appropriate amount of Si is included to ensure the insulating properties of the insulating film 20.

F may also be derived from F in the silane compound. An appropriate amount of F can be included to improve chemical resistance, insulation, and corrosion resistance of the insulating coating 20.

The insulating film 20 may include elements derived from the insulating film composition such as Cr, Fe, C, O and the electrical steel sheet substrate 10 in addition to Si and F.

The thickness of the insulating film 20 may be 0.1 to 10㎛. If the thickness of the insulating film 20 is too thin, the heat resistance is lowered, there may be a problem that the iron loss is heated after the stress relief annealing. If the thickness of the insulating film 20 is too thick, the spot ratio may be lowered, which may cause a problem of inferior motor characteristics. Therefore, the thickness of the insulating film 20 can be adjusted to the above-mentioned range. More specifically, the thickness of the insulating film 20 may be 0.2 to 5 ㎛.

The electrical steel substrate 10 may be used without limitation for non-oriented electrical steel sheets or oriented electrical steel sheets. Specifically, non-oriented electrical steel sheet can be used. In one embodiment of the present invention, the insulating property is generated by the component of the insulating film 20, and may be independent of the alloy component of the electrical steel sheet. Hereinafter, as an example, the alloy component of the electrical steel sheet will be described.

Electrical steel sheet 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 Up to% wt, Ti: up to 0.005 wt%, and Sb, Sn, Bi, or a combination thereof: 0.01 to 0.15 wt%, and may include Fe and unavoidable impurities in the balance.

Hereinafter, each alloy component will be described in detail.

Hereinafter, the reason for limitation of the non-oriented electrical steel sheet base material 10 component is demonstrated.

C: 0.01 wt% or less

Carbon (C) in the embodiment according to the present invention is a component that does not greatly help to improve the magnetic properties of the electrical steel sheet is preferably removed as possible. C may be contained in an amount of 0.01% by weight or less since it causes magnetic aging in the final product and lowers its magnetic properties during use.The lower the content of C, the better the magnetic property, so it is more preferable to limit it to 0.005% by weight or less in the final product. Do.

Si: 6.0 wt% or less

Silicon (Si) is a component that reduces the eddy current loss during iron loss by increasing the specific resistance of the steel, if the content of Si is too large, the brittleness may increase, which makes it difficult to cold rolling. Therefore, it is desirable to limit to 6.0% by weight or less. More specifically Si may be included 0.1 to 4.0% by weight.

P: 0.5 weight% or less

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

S: 0.005 wt% or less

Sulfur (S) is to be managed as low as possible because it forms a fine precipitates MnS and CuS and inhibits grain growth to deteriorate the magnetic properties, so the content is limited to 0.005% by weight or less.

Mn: 0.1-1.0 wt%

When manganese (Mn) is present in less than 0.1% by weight, fine MnS precipitates are formed, which inhibits grain growth, thereby deteriorating magnetism. Therefore, when 0.1 weight% or more exists, coarse MnS is formed and S component can be prevented from being precipitated by CuS which is a finer precipitate. However, when Mn increases, since magnetic deteriorates, it adds at 1.0 weight% or less.

Al: 0.40 to 2.0 wt%

Al is an effective component to lower the eddy current loss by increasing the specific resistance. In the case of less than 0.40% by weight, AlN is finely precipitated and inferior in magnetism, and when it exceeds 2.0% by weight, the workability is deteriorated, so it is preferable to limit it to 2.0% by weight or less.

N: 0.005 wt% or less

Since N forms fine and long AlN precipitates inside the base material and suppresses grain growth, the content of N is preferably less than 0.005% by weight.

Ti: 0.005 wt% or less

Ti inhibits grain growth by forming fine precipitates of TiN and TiC, and when added in excess of 0.005% by weight, many fine precipitates occur to worsen the texture and deteriorate the magnetic properties.

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

Sb, Sn, or Bi is a surface precipitation element, which concentrates on the surface of the steel sheet to suppress the adsorption of nitrogen, and consequently serves to lower iron loss by not inhibiting the growth of crystal grains. Sb, Sn, or Bi alone or in combination If the content is too small, the effect may be reduced. If the content of Sb, Sn, or Bi alone or in combination is too high, grain boundary segregation may occur severely, leading to brittleness of the steel sheet, which may cause plate breakage during rolling. When two or more kinds of Sb, Sn, and Bi are added in combination, the total amount thereof may be 0.01 to 0.15 wt%.

More specifically, Sb may include 0.01 to 0.05% by weight, Sn to 0.01 to 0.12% by weight, Bi may include 0.01 to 0.06% by weight.

Manufacturing method of electrical steel

Figure 2 schematically shows a flow chart of the manufacturing method of the electrical steel sheet according to an embodiment of the present invention. The flowchart of the manufacturing method of the electrical steel sheet of FIG. 2 is merely for illustrating the present invention, 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 manufacturing method of the electrical steel sheet comprises the steps of preparing the electrical steel sheet (S10); And applying an insulating coating composition to one or both surfaces of the electrical steel sheet to form an insulating coating (S20). In addition, the manufacturing method of the electrical steel sheet may further include other steps.

First, in step S10 to prepare an electrical steel sheet substrate. Since the alloy component of the electrical steel sheet substrate has been described in detail, repeated descriptions are omitted.

The manufacturing of the electrical steel sheet may include hot rolling the slab to prepare a hot rolled sheet; Cold rolling of the hot rolled sheet may include producing a cold rolled sheet and the final annealing of the cold rolled sheet.

First, the slab is heated. At this time, the slab heating may be heated at 1,200 ℃ or less.

Next, the heated slab is hot rolled to produce a hot rolled sheet. The produced hot rolled sheet can be hot rolled annealed.

Next, the hot rolled sheet is cold rolled to produce 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. In this case, in the final annealing of the cold rolled sheet, the rolling oil present in the cold rolled sheet may be degreased and subjected to the first annealing, and the second annealing may be performed in an atmosphere composed of hydrogen and nitrogen. In addition, the final annealing can control the dew point temperature to -5 ℃ or less for the purpose of preventing the formation of oxide on the surface of the magnetic deterioration.

Returning to the description of the manufacturing method of the electrical steel sheet, the next step (S20) to form an insulating coating by applying an insulating coating composition on one side or both sides of the electrical steel substrate. Since the insulation coating composition is the same as that described above, overlapping descriptions are omitted.

The forming of the insulating film may include heat treating the steel sheet to which the insulating coating composition is applied at a temperature of 100 to 680 ° C. If the heat treatment temperature is too low, the removal of the solvent is not easy, and a beautiful insulating film is hardly formed. Too high a heat treatment temperature may cause a problem of inferior adhesion. More specifically, the heat treatment may be performed at a temperature of 350 to 650 ° C. The heat treatment time may be 5 to 200 seconds.

After forming the insulating film, it may further include the step of stress relief annealing at a temperature of 700 to 1000 ℃. In one embodiment of the present invention, the adhesion and surface properties of the insulating film can be excellently maintained even after stress relief annealing by the silane compound and the chromic acid compound in the insulating film composition. 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 stress relief annealing step 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 with reference to Examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experimental Example  One : Silane  Kinds of Compounds

Example 1

3.4% by weight of silicon (Si), aluminum (Al): 0.80% by weight, manganese (Mn): 0.17% by weight titanium (Ti): 0.0015% by weight, tin (Sn): 0.03% by weight, bismuth (Bi): 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, and the balance consists of Fe and other unavoidable impurities Slabs were prepared.

The slab was heated at 1130 ° C. and 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, subjected to hot rolled sheet annealing at 1040 ° C. for 2 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm to prepare a cold rolled sheet.

The cold rolled sheet was annealed at 1040 ° C. for 50 seconds in an atmosphere of 20% hydrogen and 80% nitrogen, and then subjected to final annealing to prepare an annealed steel sheet.

As an insulating coating composition, 60 parts by weight of triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane), 20 parts by weight of chromic anhydride (CrO ₃ ), 10 parts by weight of magnesium oxide (MgO) and 5 parts by weight of ethylene glycol with distilled water The mixture was prepared in the form of a slurry, the slurry was applied to the final annealed steel sheet using a roll, and then heat-treated at 650 ° C. for 25 seconds and cooled in air. The electrical steel sheet was subjected to Stress Relief Annealing (SRA) at 100% nitrogen atmosphere at 820 ° C. for 2 hours, and then cooled in air. The thickness of the insulating film was about 0.8 μm.

Examples 2-12

In the same manner as in Example 1, the content and type of the silane compound, the chromic acid compound and the ceramic powder in the insulation coating composition were replaced as shown in Table 1 to form an insulation coating.

Comparative Example 1

In the same manner as in Example 1, without using a chromic acid compound, an insulating coating composition containing 100 parts by weight of triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane) was used.

Comparative Example 2

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

Comparative Example 3

In the same manner as in Example 1, without using a silane compound, an insulating coating composition including 60 parts by weight of chromic anhydride and 40 parts by weight of magnesium oxide was used.

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

The iron loss (W _15/50) refers to the power loss that appears when sikyeoteul magnetized with the alternate current magnetic field frequency of 50Hz to 1.5Tesla.

In addition, the insulation properties were measured by using a Franklin meter in accordance with the ASTM A717 International Standard.

In addition, the adhesion is shown by 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 characteristic is a result of visually evaluating the degree to which a uniform film is formed and a uniform color.

division Silane compound
(Part by weight) Chromic acid compound
(Part by weight) Ceramic powder
(Part by weight) Comparative Example 1 K1 (100) - - Comparative Example 2 - CrO ₃ (100) - Comparative Example 3 - CrO ₃ (60) MgO (40) Example 1 K1 (60) CrO ₃ (30) MgO (5) Example 2 K2 (50) CrO ₃ (30) MgO (10), 9Al ₂ O _{3B 2} O ₃ (3) Example 3 K3 (70) Cr ₂ O ₃ (20) MgO (7) Example 4 K4 (33) CrO ₃ (50) CaO (10), BN (2) Example 5 K1 (30), K2 (25) K ₂ Cr ₂ O ₇ (40) Al ₂ O ₃ (4) Example 6 K1 (35), K3 (10), K4 (5) Na ₂ Cr ₂ O ₇ (20) SiO ₂ (10), Y ₂ O ₃ (10) Example 7 K2 (45) CrO ₃ (40) TiO ₂ (7), CrN (3) Example 8 K2 (30) Cr ₂ O ₃ (30) ZrO ₂ (35), BaTiO ₃ (3) Example 9 K3 (48) CrO ₅ (40) _{Al 2 O 3 · TiO 2 (} 0.5) Example 10 K1 (10), K2 (10), K3 (10), K4 (15) CrO ₃ (35) SiC (5), TiC (5) Silane compound
K1: Triethyl (trifluoromethyl) silane
K2: Trimethoxy (3,3,3-trifluoropropyl) silane
K3: Dimethoxy-methyl (3,3,3-trifluoropropyl) silane
K4: 1H, 1H, 2H, 2H-Perfluorooctyl-triethoxysilane

division Iron loss
_{(W 15/50, W /} kg) Insulation (mA) Adhesiveness (mmφ) Surface feature Comparative Example 1 3.17 990 70 Surface peeling extreme Comparative Example 2 3.65 990 70 Surface peeling extreme Comparative Example 3 3.14 990 70 Surface peeling extreme Example 1 2.55 682 10 Uniformity Example 2 2.24 677 10 Uniformity Example 3 2.33 712 10 Uniformity Example 4 2.27 550 15 Uniformity Example 5 2.01 611 10 Uniformity Example 6 2.03 650 10 Uniformity Example 7 2.33 588 10 Uniformity Example 8 1.89 645 15 Uniformity Example 9 2.13 711 10 Uniformity Example 10 1.91 327 20 Uniformity

As shown in Table 1 and Table 2, it can be confirmed that the insulating film characteristic of the Example is superior to the comparative example. In addition, when the silane compound or the chromic acid compound is included alone, peeling of the film occurs excessively and it can be confirmed that the magnetic properties are deteriorated.

3 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 2. FIG.

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

Experimental Example  2: Evaluation of Polymer Resin Addition Effect

Example 11

4.5 wt% of silicon (Si), 0.80 wt% of aluminum (Al), 0.15 wt% of manganese (Mn), 0.001 wt% of titanium (Ti), 0.05 wt% of tin (Sn), and 0.004 of carbon (C) Wt%, nitrogen (N) 0.0015% by weight, phosphorus (P) 0.015% by weight, sulfur (S) 0.001% by weight, the balance was prepared a slab consisting of Fe and other unavoidable impurities.

The slab was heated at 1150 ° C. and 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, subjected to hot rolled sheet annealing at 1040 ° C. for 3 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm 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 at 1050 ° C. for 60 seconds, and subjected to final annealing to prepare an annealed steel sheet.

Thereafter, the polymer resin was mixed in the insulating coating composition described in Example 2 as summarized in Table 3 below to prepare a slurry, heat treated at 650 ° C. for 30 seconds, and cooled in air. The steel sheet was subjected to Stress Relief Annealing (SRA) heat treatment at 100% nitrogen atmosphere at 820 ° C. for 2 hours, and cooled in air. The insulating film was formed to a thickness of about 0.4 mu m.

The stress relief annealed steel sheet was treated for 24 hours at 60 ° C. and 95% humidity for 24 hours.

division Polymer resin
(Part by weight) Iron loss
(W15 / 50, W / kg) Surface roughness
(Μm) Drip rate
(%) Rust generation area
(%) Example 11 Acrylic resin
(12) 2.11 0.35 98.3 0.6 Example 12 Styrene resin
(15) 2.05 0.25 98.5 1.5 Example 13 Vinyl acetate resin
(7) 2.17 0.23 98.8 2.2 Example 14 Polyester resin
20 2.35 0.37 98.2 7.7 Example 15 Urethane resin
(7) 2.31 0.32 98.5 3.8 Example 16 Polyethylene resin
(5) 1.99 0.35 98.4 9.8 Example 17 Polypropylene resin
(5) 2.15 0.33 98.4 1.0 Example 18 Polyamide resin
(9) 2.11 0.22 99.1 3.0 Example 19 Polycarbonate resin
(15) 2.51 0.25 99.0 2.5 Example 20 Phenolic resin
(5) 2.20 0.35 98.1 0.7 Example 21 Alkyd resin
(6) 2.22 0.33 98.1 3.3 Example 22 Epoxy resin
(18) 1.88 0.18 99.5 0.3

As shown in Table 3, changes in iron loss, surface roughness, area ratio, and rust generation area were confirmed according to the change in the type and amount of the polymer resin.

The present invention is not limited to the embodiments and can be manufactured in various different forms, and those skilled in the art to which the present invention pertains may change to other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it may be practiced. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

100: electrical steel sheet
10: electric steel substrate
20: insulation film

Claims (19)

A silane compound represented by Formula 1 below; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.
[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.) The method of claim 1,
An insulating coating composition for electrical steel sheet comprising 10 to 80 parts by weight of the silane compound and 20 to 90 parts by weight of the chromic acid compound, based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound. The method of claim 1,
In Formula 1, R ¹ is hydrogen, a halogen element, a linear or branched alkyl group or an alkoxy group insulation coating composition for electrical steel sheet. The method of claim 1,
In Chemical Formula 1, L is a direct bond, an alkylene group, and at least one of -CF ₂ -insulation coating composition for electrical steel sheet. The method of claim 1,
The silane compound is an insulating film composition for electrical steel sheet represented by the following formula (2).
[Formula 2]

R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, 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 a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.) The method of claim 5,
In Formula 2, R ² and R ³ are each independently an insulating coating composition for an electrical steel sheet which is hydrogen or a halogen element. The method of claim 1,
The silane compound is triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane), Trimethoxy (trifluoropropyl) silane (trimethoxy propyl) silane), Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-) Insulation coating composition for electrical steel sheets containing at least 1 sort (s) of methyl (tripulo propyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl triethoxysilane). The method of claim 1,
The insulating coating composition for electrical steel sheet containing 0.5-65 weight part of ceramic powders with respect to 100 weight part of total amounts of the said silane compound and the said chromic acid compound. The method of claim 8,
The ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, ZrO 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O ₃ , BN, CrN, BaTiO ₃ , SiC and TiC, including an insulating coating composition for electrical steel sheet. The method of claim 8,
The average particle diameter of the ceramic powder is 0.05 to 20㎛ insulating film composition for electrical steel sheet. The method of claim 8,
Acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin, polyamide resin, polycarbonate resin, phenol resin, based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound Insulating coating composition for electrical steel sheet further comprising 0.5 to 30 parts by weight of at least one polymer resin of alkyd resin and epoxy resin. The method of claim 1,
1 to 15 weights of one or more of ethylene glycol, propylene glycol, glycerine, and butyl carbitol based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound. Insulating coating composition for electrical steel sheet comprising a further. Electrical steel substrate and
Insulating coating on one side or both sides of the electrical steel sheet substrate,
The insulating film is a silane compound represented by the following formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.
[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.) The method of claim 13,
The insulating film is an electrical steel sheet containing 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F. The method of claim 13,
The insulating film has a thickness of 0.1 to 10㎛ electrical steel sheet. Manufacturing an electrical steel sheet substrate; And
Forming an insulating coating by coating the insulating coating composition on one or both surfaces of the electrical steel sheet substrate,
The insulating coating composition is a silane compound represented by the formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.
[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, 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 from 1 to 4, n is 4-m.) The method of claim 16,
The step of manufacturing the electrical steel sheet is
Hot rolling the slab to produce a hot rolled plate;
Cold rolling the hot rolled sheet to produce a cold rolled sheet;
A method of manufacturing an electrical steel sheet comprising the final annealing of the cold rolled sheet. The method of claim 16,
Forming the insulating film is a method of manufacturing an electrical steel sheet comprising the step of heat-treating the steel sheet coated with the insulating coating composition at a temperature of 100 to 680 ℃. The method of claim 16,
After forming the insulating film,
Method for producing an electrical steel sheet further comprising the step of stress relief annealing at a temperature of 700 to 1000 ℃.

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