KR20230092809A - Insulation coating composition for electrical steel sheet, electrical steel sheet comprising same, and method of manufacturing thereof - Google Patents

Abstract

The insulation coating composition according to an embodiment of the present invention includes a resin having an average particle diameter of 50 to 250 nm, a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn, and a metal chloride, and the above The amount of the metal chloride may be 1 to less than 40 parts by weight based on solid content, based on 100 parts by weight of the total insulation coating composition.

Description

Insulation coating composition for electrical steel sheet, electrical steel sheet comprising the same, and manufacturing method thereof

The present invention relates to an electrical steel sheet, and more particularly, to an insulation coating composition for electrical steel sheet, an electrical steel sheet including the same, and a manufacturing method thereof.

Electrical steel is a product used as a material for transformers, motors, and electronic devices. Unlike general carbon steel, which emphasizes workability such as mechanical characteristics, electrical steel is a functional product that values electrical characteristics. The electrical properties include characteristics such as iron loss, magnetic flux density, magnetic permeability, and spotting factor, and the electrical steel sheet is characterized by low iron loss and high magnetic flux density, magnetic permeability, and spotting factor.

The electrical steel sheet is largely divided into grain-oriented electrical steel sheet and non-oriented electrical steel sheet. The grain-oriented electrical steel sheet is an electrical steel sheet having excellent magnetic properties in the rolling direction by forming a {100}<001> texture, which is a Goos texture, over the entire steel sheet using an abnormal grain growth phenomenon called secondary recrystallization. The non-oriented electrical steel sheet is an electrical steel sheet having uniform magnetic properties in all directions on a rolled sheet.

The formation of an insulating film on the non-oriented electrical steel sheet is a process corresponding to the final manufacturing process of the product, and in addition to the electrical properties of suppressing the occurrence of eddy currents, the wear of the mold when manufacturing an iron core by stacking a plurality of sheets after punching in a predetermined shape After stress relief annealing (SRA), which restores magnetic properties by removing the processing stress of the steel sheet and the continuous punching workability that suppresses the processing stress of the steel sheet, sticking resistance that does not adhere between the core steel sheets, and surface adhesion, laminated core When welding the side for fixing, it is required to have good weldability. In addition to these basic properties, excellent application of the coating solution and solution stability that can be used for a long time after mixing are also required.

Among them, the welding is performed for the purpose of fixing the laminated cores. Due to the nature of the welding at high temperatures, the organic matter of the coating layer vaporizes, leaving pores that are partially trapped or escaped marks in the welding solution. (Blow-Hole) defects may also be caused. Recently, along with the development of high-efficiency motors, as materials are thinned to reduce eddy current loss, the number of defects in the coating layer is relatively increased while the amount of the coating layer is relatively increased.

In this way, the defects appearing as a decrease in the area ratio due to the thinning of the material require a method for improving weldability while maintaining the thickness of the coating layer.

A technical problem to be solved by the present invention is to provide an insulation coating composition capable of improving weldability in an electrical steel sheet.

Another technical problem to be solved by the present invention is to provide an electrical steel sheet including a coating layer composition having the above advantages.

Another technical problem to be solved by the present invention is to provide a method for producing an insulation coating composition having the above advantages.

According to one embodiment of the present invention, the insulation coating composition includes a resin having an average particle diameter of 50 to 250 nm, a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn, and a metal chloride, The amount of the metal chloride may be 1 to less than 40 parts by weight, based on solid content, based on 100 parts by weight of the total insulation coating composition. In one embodiment, the metal chloride may be at least one of Al, Ca, Mg, Sr, Zn, and Fe. In one embodiment, the metal chloride may include at least one of iron sulfate (FeSO ₄ ), aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, and zinc sulfate.

In one embodiment, the ratio of the resin to the metal phosphate may be 1/9 to 1 based on the solid content. In one embodiment, the metal phosphate may include at least one of aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, and zinc phosphate.

According to another embodiment of the present invention, an electrical steel sheet includes an electrical steel sheet substrate and an insulating coating layer applied on the electrical steel substrate substrate, wherein the insulating coating layer is selected from among resin, Mg, Al, Ca, Sr, Mn, and Zn. It includes at least one metal phosphate and at least one metal chloride of Al, Ca, Mg, Sr, Zn, and Fe, wherein the metal chloride is present in an amount of 1 to 40, based on solid content, based on 100 parts by weight of the total insulating coating composition. It is less than a part by weight, and the coating thickness difference rate of the insulating coating layer may satisfy Equation 1 below.

<Equation 1>

10 ≤ ((coating thickness at the thickest part - coating thickness at the thinnest part)/average coating thickness) × 100 ≤ 40

In one embodiment, at least one of the metal chlorides may include iron sulfate (FeSO ₄ ). In one embodiment, the glossiness of the electrical steel sheet may be 60 GU or more. In one embodiment, the surface roughness of the electrical steel sheet may be 0.28 to 0.51 μm.

According to another embodiment of the present invention, a method of manufacturing an insulation coating composition is a resin containing an organic material, at least one of Mg, Al, Ca, Sr, Mn, and Zn, a metal phosphate of the resin for the metal phosphate. Mixing at a ratio of 1/9 to 1 based on solid content, and mixing at least one metal chloride of Al, Ca, Mg, Sr, Zn, and Fe with respect to 100 parts by weight of the mixture, It may include the step of adding from 1 to less than 40 parts by weight based on solids. In one embodiment, the metal chloride may include at least one of iron sulfate (FeSO ₄ ), aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, and zinc sulfate. In one embodiment, the metal phosphate may include at least one of aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, and zinc phosphate.

Insulation coating composition according to an embodiment of the present invention contains a resin, a metal phosphate, and a metal sulfate, so that when coated on an electrical steel sheet, surface roughness is imparted and a gas channel is secured between materials to prevent welding. Occurrence of blow-hole defects can be prevented.

An electrical steel sheet according to another embodiment of the present invention may provide an electrical steel sheet having surface roughness and good weldability by including the insulating coating composition having the above advantages.

The method for manufacturing an insulation coating composition according to another embodiment of the present invention can manufacture an insulation coating composition having the above advantages.

1 shows an electrical steel sheet according to an embodiment of the present invention.
2a to 2d are cross-sectional SEM (Scanning Electron Microscope) images of the insulating film according to the amount of metal sulfate added according to an embodiment of the present invention.
3A to 3D are welded cross-sectional images of electrical steel sheets coated with insulating coatings according to the amount of metal sulfate added according to an embodiment of the present invention.

Terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and/or sections. 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 only for referring to specific embodiments and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising" as used herein specifies particular characteristics, regions, integers, steps, operations, elements and/or components, and the presence or absence of other characteristics, regions, integers, steps, operations, elements and/or components. Additions are not excluded.

When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part or may be followed by another part therebetween. In contrast, when a part is said to be “directly on” another part, there is no intervening part between them.

Although not defined differently, all terms including technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

In addition, unless otherwise specified, % means weight%, and 1ppm is 0.0001 weight%.

In one embodiment of the present invention, the meaning of further including an additional element means replacing and including iron (Fe) as much as the additional amount of the additional element.

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

According to one embodiment of the present invention, the insulation coating composition includes at least one of a resin, a metal phosphate, and a metal chloride. Specifically, the composition of the insulating coating may be an insulating coating composition for electrical steel sheet, which is applied to the electrical steel sheet to improve properties such as material adhesion, corrosion resistance, and punchability.

The resin is included in the insulation coating composition and may function as a binder. In one embodiment, the resin may be an acrylic resin, an epoxy resin, a polyester resin, a styrene resin, a phenolic resin, a urethane resin, a melanin resin, a vinyl acetate resin, or a mixture of two or more thereof, and specifically, an acrylic emulsion resin. can The resin may be an emulsion or a water-soluble resin, and specifically may be an emulsion resin.

As said acrylic resin, methyl methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate , n-decyl acrylate or n-dodecyl acrylate is used as a monomer, and a monomer having a functional group such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid or itaconic acid, or A monomer having a hydroxyl group such as 2-hydroxylethyl (meth)acrylate, 2-hydroxylpropyl (meth)acrylate, 3-hydroxylbutyl (meth)acrylate, or 2-hydroxylethyl (meth)aryl ether A copolymerized product can be more suitably used.

As the epoxy resin, one obtained by reacting an amine-modified epoxy resin with carboxylic acid anhydride can be used. For example, bisphenol A-diglycidyl ether, caprolactone ring-opening adduct of bisphenol A-diglycidyl ether, bisphenol F-diglycidyl ether, bisphenol S-diglycidyl ether, novolakglycy Epoxy resins such as dilether and dimer acid glycidyl ether, isopropanolamine, monopropanolamine, monobutanolamine, monoethanolamine, diethylenetriamine, ethylenediamine, butylamine, propylamine, isophoronediamine, tetra It is modified by the action of an amine such as hydrofurfurylamine, xylenediamine, hexylamine, nonylamine, triethylenetetramine, tetramethylenepentamine, or diaminodiphenylsulfone, and succinic anhydride, itaconic anhydride, maleic anhydride, What made by reacting carboxylic anhydride such as citraconic anhydride, phthalic anhydride or trimellitic anhydride can be suitably used.

As the polyester resin, for example, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid or sheet Dicarboxylic acids such as laconic acid, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyldiol, 1,6-hexanediol, A polyester resin obtained by reacting glycol such as triethylene glycol, dipropylene glycol, or polyethylene glycol can be suitably used. Moreover, you may use what graft-polymerized acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, methacrylic acid anhydride, etc. to the above-mentioned polyester resin.

The resin may be a resin having an average particle diameter in the range of 50 to 250 nm. Specifically, when the average particle diameter of the resin is out of the upper limit of the range, there is a problem in that coating wetting performance is deteriorated. When the average particle diameter of the resin is out of the lower limit of the range, there is a problem in that the stability of the solution is lowered.

The metal phosphate may be a solid content obtained by drying an aqueous solution containing phosphoric acid and metal ions as main components, and may function as a binder in an insulating film. In one embodiment, the metal phosphate is magnesium (Mg), aluminum (Al), calcium (Ca), strontium (Sr), manganese (Mn), and zinc (Zn) any one or more metal phosphates can Specifically, the metal phosphate may be at least one of aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, and zinc phosphate.

In one embodiment, the ratio of the resin to the metal phosphate may be 1/9 to 1 based on the solid content. Specifically, the ratio of the metal phosphate and the resin based on the solid content may be 9:1 to 5:5. When the ratio of the metal phosphate is excessively high compared to the ratio of the resin, there is a problem in that mold deterioration occurs in the punching process. If the ratio of the resin is too high, there is a problem of causing peeling of the coating layer including the insulation coating composition after stress relief annealing.

The metal chloride may be added to facilitate coagulation of the resin. In general, the resin is uniformly distributed in the coating layer during heating and drying or curing, so that it is difficult to improve weldability because it does not impart roughness to the surface. By adding the metal sulfate or the metal chloride to the resin, the ionic strength of the solution for forming the insulating coating composition may be increased.

Therefore, when iron ions are eluted through a reaction with the material surface during the process of heat drying or curing of the solution for forming the insulation coating composition, the ionic strength of the metal chloride increases, thereby increasing the surface roughness of the insulation coating composition through aggregation of the resin particles. can be granted

In one embodiment, the metal chloride may be a material capable of forming ions by dissolving in water and forming an insoluble film through heat curing or salt formation after drying. In one embodiment, the metal chlorides may include metal sulfates and metal nitrates. The metal chloride may include nitrite (-NO ₃ ) sulfide (-SO ₄ ), chloride (-Cl), or carbonate (-CO ₃ ) to form a salt.

In one embodiment, the metal chloride may include at least one of aluminum (Al), calcium (Ca), magnesium (Mg), strontium (Sr), zinc (Zn), and iron (Fe). The metal chloride specifically includes the iron, and may be iron sulfate (FeSO ₄ ) or aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, or zinc sulfate.

In one embodiment, the metal chloride may be added in a range of 1 to less than 40 parts by weight based on solid content, based on 100 parts by weight of the entire insulation coating composition. Specifically, the range may be 10 to 30 parts by weight.

If the upper limit of the above range is exceeded, the stability of the solution may decrease or the surface friction coefficient may increase, resulting in workability problems such as slit processing, and the boiling point of the coating layer may increase, resulting in weldability evaluation. There is a problem of increasing blow-holes. If it is out of the lower limit of the range, there is a problem that it is difficult to expect the effect of improving weldability.

1 shows an electrical steel sheet 100 according to an embodiment of the present invention.

Referring to FIG. 1 , an electrical steel sheet 10 according to an embodiment of the present invention may include an electrical steel substrate 100 and an insulating coating layer 200 . In the electrical steel sheet 10, for example, by applying the insulating coating layer 200 to the electrical steel base material 100, which is the surface of the non-oriented electrical steel sheet, properties such as material adhesion, corrosion resistance, punchability, insulation, and weldability can be improved. can

The electrical steel sheet substrate 100 may be a grain oriented electrical steel sheet having excellent magnetic properties in the rolling direction by forming a {100}<001> texture, which is a Goos texture, throughout the steel sheet using an abnormal grain growth phenomenon called secondary recrystallization, It may be a non-oriented electrical steel sheet having uniform magnetic properties in all directions on the rolled sheet. Specifically, according to an embodiment of the present invention, the electrical steel sheet substrate 100 may be a non-oriented electrical steel sheet.

The insulation coating layer 200 is applied on the electrical steel substrate 100, and is formed by applying the above-described insulation coating composition to the electrical steel substrate 100 and then drying it. The insulation coating composition is the same as described above within a range not contradictory.

In one embodiment, the insulating coating layer 200 may include a resin, a metal phosphate, and a metal chloride. Since the resin, the metal phosphate, and the metal chloride are the same within a range not inconsistent with those described above, detailed descriptions are omitted.

In one embodiment, the insulating coating layer 200 is applied on the surface of the electrical steel sheet substrate 100 and may be positioned in an external direction from the surface of the electrical steel sheet substrate 100 to the outside of the electrical steel sheet 10 . Insulation coating layer 200 is coated with a coating solution for the insulation coating composition, and in the drying step, when the coating solution reacts with the electrical steel sheet 10, some of the Fe component included in the substrate is in the form of ions on the solution. It may be melted and formed.

After the insulation coating layer 200 is formed, the insulation coating layer 200 of the electrical steel sheet 10 may have a coating thickness difference rate, and the coating thickness difference rate may satisfy Equation 1 below.

<Equation 1>

10 ≤ ((coating thickness at the thickest part - coating thickness at the thinnest part)/average coating thickness) × 100 ≤ 40

Referring to Equation 1, the coating thickness difference rate is the difference between the thickness of the thickest portion of the coated portion and the thickness of the thinnest coated portion of the coated portion with respect to the average value of the coating thickness expressed as a percentage. The coating thickness difference rate may be in the range of 10 to 40.

When the range of the coating thickness difference ratio excessively exceeds the upper limit, there is a problem in that glossiness is reduced. When the range of the coating thickness difference rate excessively exceeds the lower limit, there is a problem in that weldability is deteriorated.

In one embodiment, the glossiness of the electrical steel sheet 10 may be 60 GU or more. The glossiness is measured at a measurement angle of 60 °, and when the glossiness is lower than 60, there is a problem in that the appearance of the electrical steel sheet 10 is not beautiful.

In one embodiment, the surface roughness (Ra) of the electrical steel sheet 10 may range from 0.28 to 0.51 μm. When the surface roughness is out of the upper limit of the range, there is a problem in that the space factor is lowered and the weldability is lowered. When the surface roughness is out of the lower limit of the range, the cost tends to increase during the cold rolling process, and there is a problem in that weldability deteriorates.

According to an embodiment of the present invention, a method for manufacturing an insulation coating composition includes a resin containing an organic material, a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn, for the metal phosphate. Mixing at a ratio of 1/9 to 1 based on solid content, and mixing at least one metal chloride of Mg, Al, Fe, Co, Mn, and Zn with respect to 100 parts by weight of the mixture for the mixture that has undergone the mixing step as solid content It may include the step of adding from 1 to less than 40 parts by weight on a basis. Since the resin, the metal phosphate, and the metal chloride are the same within a range not inconsistent with those described above, detailed descriptions are omitted.

The step of mixing a resin containing an organic material, a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn at a ratio of 1/9 to 1 based on the solid content of the resin to the metal phosphate. and the metal phosphate are mixed to synthesize a solution for forming an insulation coating composition. The resin may be, specifically, an acrylic emulsion resin, and the metal phosphate may be, specifically, aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, or zinc phosphate. For a detailed description thereof, reference may be made to the description of the above-described insulation coating composition within a range that is not contradictory.

The step of adding at least one metal chloride of Mg, Al, Fe, Co, Mn, and Zn in an amount of 1 to less than 40 parts by weight based on solid content with respect to 100 parts by weight of the mixture to the mixture that has undergone the mixing step is the insulation coating composition. In the solution for formation, the metal chloride may be specifically added to facilitate aggregation of the resin. Specifically, the metal chloride may be iron sulfate (FeSO ₄ ), aluminum sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, or zinc sulfate, and a detailed description thereof does not contradict the description of the above-described insulation coating composition. can be referenced in scope.

Hereinafter, specific embodiments of the present invention will be described. However, the following examples are only specific examples of the present invention, but the present invention is not limited to the following examples.

Example 1

A non-oriented electrical steel sheet (150*50 mm) containing 3.15% by weight of silicon (Si) and having a thickness of 0.27 mm was used as a specimen, and the non-oriented electrical steel sheet was prepared as shown in Table 1 below. After applying the prepared solution to a thickness of 0.4 to 0.6 μm on each prepared specimen using a bar coater and a roll coater, hold it in a dry furnace at 300 to 750 ° C for 10 to 30 seconds, and then slowly in the air. Cooled down.

At this time, the solution was mixed with an acrylic emulsion resin and aluminum phosphate (AlPO ₄ , Al(H ₂ PO ₄ ) ₃ , Al ₂ (HPO ₄ ) ₃ ) in a ratio of 3:7 to synthesize a solution for forming an insulating coating composition. , When synthesizing the above solution, 1% of iron sulfate (FeSO ₄ ) was added as an additive.

Example 2

Except for adding 10% of the iron sulfate (FeSO ₄ ), the rest was carried out in the same manner as in Example 1.

Example 3

Except for adding 30% of the iron sulfate (FeSO ₄ ), the rest was carried out in the same manner as in Example 1.

Example 4

The rest was carried out in the same manner as in Example 1 except that the emulsion having an average particle diameter of 50 μm was used.

Example 5

Except for using the emulsion having an average particle diameter of 100 μm, the rest was performed in the same manner as in Example 1.

Example 6

The rest was carried out in the same manner as in Example 1 except that the emulsion having an average particle diameter of 250 μm was used.

Example 7

Except for using magnesium phosphate (Mg ₃ (PO ₄ ) ₂ , Mg(HPO ₄ ), Mg(H ₂ PO ₄ ) ₂ ) instead of aluminum phosphate as the phosphate, the rest was carried out in the same manner as in Example 1.

Example 8

Except for using calcium phosphate (Ca ₃ (PO ₄ ) ₂ , Ca(HPO ₄ ), Ca(H ₂ PO ₄ ) ₂ ) instead of aluminum phosphate as the phosphate, the rest was carried out in the same manner as in Example 1.

Example 9

Except for using strontium phosphate (Sr ₃ (PO ₄ ) ₂ , Sr(HPO ₄ ), and Sr(H ₂ PO ₄ ) ₂ ) instead of aluminum phosphate as the phosphate, the rest was carried out in the same manner as in Example 1.

Example 10

Except for the fact that manganese phosphate (Mn ₃ (PO ₄ ) ₂ , Mn (HPO ₄ ), Mn (H ₂ PO ₄ ) ₂ ) was used instead of aluminum phosphate as the phosphate, the rest was carried out in the same manner as in Example 1.

Example 11

Except for using zinc phosphate (Zn3(PO ₄ ) ₂ , Zn(HPO ₄ ) , Zn(H ₂ PO ₄ ) ₂ ) instead of aluminum phosphate as the type of phosphate, the rest was carried out in the same manner as in Example 1.

Example 12

Except for using aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) instead of iron sulfate as the inorganic additive, the rest was carried out in the same manner as in Example 1.

Example 13

Except for using calcium sulfate (CaSO ₄ ) instead of iron sulfate as the inorganic additive, the rest was carried out in the same manner as in Example 1.

Example 14

Except for using magnesium sulfate (MgSO ₄ ) instead of iron sulfate as the inorganic additive, the rest was carried out in the same manner as in Example 1.

Example 15

Except for using manganese sulfate (MnSO ₄ ) instead of iron sulfate as the inorganic additive, the rest was carried out in the same manner as in Example 1.

Example 16

Except for the fact that strontium sulfate (SrSO ₄ ) was used instead of iron sulfate as the inorganic additive, the rest was carried out in the same manner as in Example 1.

Comparative Example 1

Except for not adding the iron sulfate (FeSO ₄ ), the rest was carried out in the same manner as in Example 1.

Comparative Example 2

Except for adding 40% of the iron sulfate (FeSO ₄ ), the rest was carried out in the same manner as in Example 1.

Comparative Example 3

Except for adding 50% of the iron sulfate (FeSO ₄ ), the rest was carried out in the same manner as in Example 1.

Comparative Example 4

The rest was performed in the same manner as in Example 1 except that the emulsion having an average particle diameter of 30 μm was used.

Comparative Example 5

Except for using the emulsion having an average particle diameter of 300 μm, the rest was performed in the same manner as in Example 1.

Equation 1 below evaluates the effect of the present invention according to the above-described Examples and Comparative Examples. Specifically, solution stability, glossiness, material roughness, surface roughness, thickness difference rate, weldability, and adhesion after heat treatment were evaluated, respectively.

Solution stability was measured by DLS Terbiscan, gloss was measured using a gloss meter, and material roughness and surface roughness were measured using a roughness meter. The thickness difference ratio was calculated by comparing the thickness difference between the thickest part and the thinnest part within 40 μm through SEM cross-sectional analysis. Weldability was evaluated through external inspection and cross-sectional inspection after TIG welding in Lab experiments.

Adhesion after heat treatment was evaluated by ASTM D3359 after heat treatment at 750 °C in a N ₂ atmosphere.

Evaluation of the weldability and the adhesion were indicated as excellent (◎), good (○), average (Δ), and poor (×). In the case of the above weldability, when there is no blow hole during the visual inspection and the diameter of the blow hole is 0.1 mm or less in the cross-sectional inspection, it is excellent, and when there is no blow hole during the external inspection and the diameter of the blow hole is 0.2 mm or less in the cross-sectional inspection, it is good. , When there is no blow hole during the visual inspection and the blow hole diameter exceeds 0.2 mm during the cross-section inspection, it is marked as normal, and when the blow hole is observed during the visual inspection, it is marked as defective.

Adhesion after the heat treatment was indicated as excellent when 5B or more, good when 4B, normal when 3B, and poor when 2B or less.

Experimental example profit Phosphate type inorganic additives solution
stability coating Glossiness Material surface thickness
rate of difference weldability Adhesion after heat treatment thickness illuminance illuminance profit average particle diameter
(μm) type Amount added (μm) (GU) (μm) (μm) (%) type (%) Comparative Example 1 emulsion 200 aluminum
phosphate iron sulfate 0 Good 0.5 120 0.32 0.27 One% × ◎ Example 1 emulsion 200 aluminum
phosphate iron sulfate One Good 0.5 90 0.32 0.37 10% ○ ◎ Example 2 emulsion 200 aluminum phosphate iron sulfate 10 Good 0.5 70 0.32 0.39 20% ◎ ◎ Example 3 emulsion 200 aluminum phosphate iron sulfate 30 Good 0.5 60 0.32 0.41 40% ◎ ◎ Comparative Example 2 emulsion 200 aluminum
phosphate iron sulfate 40 Good 0.5 15 0.32 0.52 70% △ ◎ Comparative Example 3 emulsion 200 aluminum
phosphate iron sulfate 50 precipitation 0.5 - 0.32 - - - - Comparative Example 4 emulsion 30 aluminum
phosphate iron sulfate 10 Good 0.5 100 0.32 0.35 25 △ △ Comparative Example 5 emulsion 300 aluminum
phosphate iron sulfate 10 Good 0.5 20 0.32 0.38 23 ◎ × Example 4 emulsion 50 aluminum
phosphate iron sulfate 10 Good 0.5 70 0.32 0.35 18% ◎ ◎ Example 5 emulsion 100 aluminum phosphate iron sulfate 10 Good 0.5 70 0.32 0.36 22% ◎ ◎ Example 6 emulsion 250 aluminum phosphate iron sulfate 10 Good 0.5 70 0.32 0.35 20% ◎ ○ Example 7 emulsion 200 magnesium iron sulfate 10 Good 0.5 70 0.32 0.41 30 ◎ ◎ phosphate Example 8 emulsion 200 calcium
phosphate iron sulfate 10 Good 0.5 70 0.32 0.45 35 ◎ ◎ Example 9 emulsion 200 Strontune iron sulfate 10 Good 0.5 70 0.32 0.42 33 ◎ ◎ phosphate Example 10 emulsion 200 manganese
phosphate iron sulfate 10 Good 0.5 70 0.32 0.38 28 ◎ ◎ Example 11 emulsion 200 zinc iron sulfate 10 Good 0.5 70 0.32 0.38 25 ◎ ◎ phosphate Example 12 emulsion 200 aluminum
phosphate aluminum sulfate 10 Good 0.5 70 0.32 0.39 20 ◎ ◎ Example 13 emulsion 200 aluminum phosphate calcium sulfate 10 Good 0.5 70 0.32 0.41 15 ◎ ◎ Example 14 emulsion 200 aluminum phosphate magnesium sulfate 10 Good 0.5 70 0.32 0.45 15 ◎ ◎ Example 15 emulsion 200 aluminum phosphate manganese sulfate 10 Good 0.5 70 0.32 0.35 20 ◎ ◎ Example 16 emulsion 200 aluminum phosphate strontium sulfate 10 Good 0.5 70 0.32 0.32 32 ◎ ◎ Example 17 emulsion 200 aluminum phosphate zinc sulfate 10 Good 0.5 70 0.32 0.35 30 ◎ ◎

Looking at Table 1, in the case of Examples 1 to 3, compared to Comparative Examples 1 to 3, it can be confirmed that there is a difference in weldability and adhesion after heat treatment. Examples 4 to 6 When the average particle diameter of the resin emulsion satisfies the range of the present invention, the weldability and adhesion after heat treatment are excellent compared to Comparative Examples 4 and 5, in which the average particle diameter of the resin emulsion does not satisfy the range of the present invention Confirmation did

Examples 7 to 11 are types of phosphates, and even when magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, or zinc phosphate is used in addition to aluminum phosphate, very good effects are obtained in terms of weldability and adhesion after heat treatment. confirmed to have.

In Examples 12 to 17, even when aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, or zinc sulfate was used in addition to iron sulfate as the inorganic additive, very good effects were obtained in terms of weldability and adhesion after heat treatment. confirmed that

2a to 2d are cross-sectional SEM (Scanning Electron Microscope) images of the insulating film according to the amount of metal sulfate added according to an embodiment of the present invention. Specifically, FIG. 2a is Comparative Example 1 without iron sulfate, FIG. 2b is Example 1, FIG. 2c is Example 2, and FIG. 2d is a cross-sectional SEM image of the insulating film for Example 3.

3A to 3D are welded cross-sectional images of electrical steel sheets coated with insulating coatings according to the amount of metal sulfate added according to an embodiment of the present invention. Specifically, FIG. 3A is Comparative Example 1 without iron sulfate, FIG. 3B is Example 1, FIG. 3C is Example 2, and FIG. 3D is a weld cross-sectional image of an electrical steel sheet coated with an insulating coating for Example 3.

Referring to Figures 2a to 2d together with Table 1, Examples 1 to 3 are excellent in gloss compared to Comparative Examples 2 and 3, and compared to Comparative Examples 1 to 3, the surface roughness is also the target of the present invention It is included in one range, and it can be confirmed that the percentage value for the difference between the thickest and thinnest parts of the coating layer with respect to the average coating layer thickness is included in the range targeted by the present invention.

Referring back to Table 1, as a result of evaluating the weldability of Examples 1 to 3, it can be confirmed that Example 1 is good (○), and Examples 2 and 3 are very good (◎). Compared to Examples 1 to 3, Comparative Example 1 had poor weldability (X), Comparative Example 2 had normal (Δ), and Comparative Example 3 could not be measured (-).

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

10: electrical steel
100: electrical steel substrate
200: insulating film layer

Claims (12)

a resin having an average particle diameter of 50 to 250 nm;
a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn; and
contains metal chlorides;
The metal chloride is 1 to less than 40 parts by weight based on solid content, based on 100 parts by weight of the total insulation coating composition.
According to claim 1,
The metal chloride is an insulating coating composition of at least one of Al, Ca, Mg, Sr, Zn, and Fe.
According to claim 1,
The metal chloride is an insulating coating composition comprising at least one of iron sulfate (FeSO ₄ ), aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, and zinc sulfate.
According to claim 1,
The ratio of the resin to the metal phosphate is 1/9 to 1 based on the solid content of the insulating coating composition.
According to claim 1,
The metal phosphate is an insulating coating composition comprising at least one of aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, and zinc phosphate.
electrical steel substrate; and
Including an insulating coating layer applied on the electrical steel substrate,
The insulating film layer includes at least one of a resin, a metal phosphate of at least one of Mg, Al, Ca, Sr, Mn, and Zn, and a metal chloride of at least one of Al, Ca, Mg, Sr, Zn, and Fe, ,
The metal chloride is 1 to less than 40 parts by weight based on solid content, based on 100 parts by weight of the total insulation coating composition,
An electrical steel sheet in which the coating thickness difference rate of the insulating film layer satisfies Equation 1 below.
<Equation 1>
10 ≤ ((coating thickness at the thickest part - coating thickness at the thinnest part)/average coating thickness) × 100 ≤ 40
According to claim 5,
At least one of the metal chlorides includes at least one of iron sulfate (FeSO ₄ ), aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, and zinc sulfate.
According to claim 5,
Electrical steel with a gloss level of 60 GU or higher.
According to claim 5,
An electrical steel sheet having a surface roughness of 0.28 to 0.51 μm.
Mixing a resin containing an organic material and at least one metal phosphate of Mg, Al, Ca, Sr, Mn, and Zn at a ratio of 1/9 to 1 based on the solid content of the resin to the metal phosphate; and
Insulation coating comprising the step of adding at least one metal chloride of Al, Ca, Mg, Sr, Zn, and Fe to the mixture that has undergone the mixing step in an amount of 1 to less than 40 parts by weight based on solid content, based on 100 parts by weight of the mixture. Method of making the composition.
According to claim 10,
wherein the metal chloride comprises at least one of iron sulfate (FeSO ₄ ), aluminum sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, strontium sulfate, and zinc sulfate.
According to claim 10,
The metal phosphate is a method of manufacturing an insulating coating composition comprising at least one of aluminum phosphate, magnesium phosphate, calcium phosphate, strontune phosphate, manganese phosphate, and zinc phosphate.

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