JP6032230B2 - Electrical steel sheet and laminated electrical steel sheet with insulation coating - Google Patents

Description

  The present invention relates to an electrical steel sheet with an insulating coating that can be bonded by heating and pressurization after lamination, and can maintain adhesion even when subjected to annealing treatment such as strain relief annealing.

  Insulating coatings on electrical steel sheets used for motors, transformers, and the like are required to have not only interlayer resistance but also various characteristics such as convenience during processing and storage, and stability during use. Since electrical steel sheets are used for various applications, various insulating coatings have been developed according to the applications.

  When the magnetic steel sheet is punched, sheared, bent, etc., the magnetic properties are deteriorated due to residual strain. In order to solve this problem, strain-removed pure is often performed at a temperature of about 700 to 800 ° C. Therefore, in this case, the insulating coating must be able to withstand strain relief annealing.

  On the other hand, there is a strong demand for higher motor efficiency to save energy, and the plate thickness tends to be thinner to reduce iron loss. However, when an iron core is manufactured using a thin steel plate, not only caulking and welding are difficult, but the laminated end face is easily opened and it is difficult to keep the shape as an iron core. For this reason, organic adhesive coatings have been proposed and put into practical use. However, this organic adhesive coating cannot withstand strain relief annealing and cannot eliminate residual strain.

  On the other hand, in Patent Document 1, a resin having a softening point temperature of room temperature to 300 ° C. is 20 to 500% by weight with respect to a low melting point glass frit, water glass, or a mixture of them with colloidal silica. An electrical steel sheet with a heat-resistant adhesive coating is disclosed. And according to this electrical steel sheet with a heat resistant adhesive coating, it is possible to bond and fix it before strain relief annealing.

  Patent Document 2 discloses an electromagnetic wave with a heat-resistant adhesive insulating coating for laminated thermocompression bonding, which is composed of an alkali metal silicate containing a specific amount of Li and K, and an organic resin binder, and has improved blocking due to hygroscopicity that easily occurs in alkali metal silicate. A steel sheet is disclosed.

Japanese Patent No. 4860480 Japanese Patent No. 4885164

  However, the coatings disclosed in Patent Documents 1 and 2 contain a resin binder and have improved low-temperature film formability and low-temperature adhesiveness. However, since there are many resins, the adhesiveness at high temperatures tends to be low. . In particular, in a motor using a thin steel plate, there is a problem that causes a peeling of a tooth portion at the time of handling such as slitting and punching lamination, leading to malfunction.

  The present invention has been made in view of such circumstances, and can be bonded by heating and pressurization after lamination, and can maintain adhesive ability even after annealing treatment such as strain relief annealing, and has sufficient core adhesion (lamination It is an object of the present invention to provide a magnetic steel sheet and a laminated magnetic steel sheet with an insulating coating having excellent annealing adhesion and having an adhesive property when an iron core is used.

The inventors of the present invention have made extensive studies to solve the above problems and have found the following.
The insulating coating contains water glass-derived substances and oxide particles in order to maintain adhesiveness even when subjected to annealing treatment such as strain relief annealing and to have adhesiveness during the annealing treatment. However, simply containing the water glass-derived material and oxide particles results in insufficient adhesion, and sufficient core adhesion cannot be obtained. On the other hand, adhesiveness becomes high by containing the specific component contained in a water glass origin thing and oxide particle | grains by a specific ratio. As a result, the above problem is advantageously solved.

The present invention is based on the above findings, and features are as follows.
[1] An electrical steel sheet having an insulating coating containing water glass-derived material and oxide particles on at least one side, wherein the water glass-derived material is composed of one or two kinds selected from Na and K as components; Si is contained, the oxide particles contain one or two kinds selected from Na and K, Si and B, and the insulating coating is (the mass of Si contained in the insulating coating in terms of SiO _2. ) / (Mass of insulating coating) is 0.20 to 0.70, (mass in terms of B ₂ O ₃ of B contained in the insulating coating) / (mass of SiO in terms of SiO _{2 of} Si contained in the insulating coating) ) Is 0.18 to 1.00, {(mass of Na contained in the insulating coating in terms of Na ₂ O) + (mass of K in the insulating coating in terms of K ₂ O)} / (above mass of SiO ₂ in terms of Si contained in the insulating film) is 0.20 to 1.0 Insulation coating with an electromagnetic steel sheet is.
[2] The electrical steel sheet with an insulating coating according to the above [1], wherein an area ratio of the oxide particles is 35% or more and 90% or less.
The area ratio of the oxide particles is the ratio of the area occupied by the oxide particles to the total area of the insulating coating.
[3] The electrical steel sheet with an insulating coating according to the above [1] or [2], wherein an average particle diameter of the oxide particles is 0.2 μm or more and 35 μm or less.
[4] The electrical steel sheet with an insulating coating according to any one of [1] to [3], wherein the oxide particles are low-melting glass.
[5] The electrical steel sheet with an insulating coating according to any one of [1] to [4], wherein the insulating coating contains 15% by mass or less of an organic resin.
[6] A laminated electrical steel sheet obtained by laminating and integrating two or more of the electrical steel sheets with insulating coatings according to any one of [1] to [5] with the insulating coating interposed therebetween.

According to the present invention, after lamination, it can be adhered by heating and pressing, and can be maintained even after annealing treatment such as strain relief annealing, has sufficient core adhesion, and has an insulating coating with excellent insulating adhesion. Steel sheets and laminated electrical steel sheets can be obtained.
Since the laminated electromagnetic steel sheets can be integrated without performing welding or caulking, it is possible to avoid iron loss deterioration, and it is possible to stack even on a thin steel sheet.
Moreover, since an adhesive state is maintained even after strain relief annealing, a laminated electrical steel sheet having excellent magnetic properties can be obtained.

  Hereinafter, the present invention will be specifically described.

The electrical steel sheet of the present invention has an insulating coating containing water glass-derived material and oxide particles on at least one side. The water glass-derived material contains, as components, one or two selected from Na and K and Si, and the oxide particles include one or two selected from Na and K, and Si. , B is contained. In addition, the insulating coating has a ratio (mass of Si in SiO ₂ equivalent to SiO ₂ ) / (insulating coating mass) of 0.20 to 0.70, and (B ₂ of B contained in the insulating coating). The mass in terms of O ₃ / (the mass in terms of SiO _{2 of} Si contained in the insulating coating) is 0.18 to 1.00, and {(the mass in terms of Na ₂ O of Na contained in the insulating coating) + (Mass of K contained in the insulating coating in terms of K ₂ O)} / (mass of Si in the insulating coating in terms of SiO ₂ ) is 0.20 to 1.00. These are important requirements in the present invention. Thus, by specifying the content of Si, B, Na, and K, that is, the content ratio contained in the composition of the insulation film and the composition of the insulation film (water glass-derived material and oxide particles), An electrical steel sheet with an insulating coating that can be bonded by pressure and can maintain adhesive ability even when subjected to an annealing treatment such as strain relief annealing, has sufficient core adhesion, and is excellent in annealing adhesion.

  In the present invention, the electromagnetic steel sheet as a material is not particularly limited, and any conventionally known steel sheet is suitable. Use all of general cold-rolled steel sheets such as so-called soft iron plates (electric iron plates) and SPCC with high magnetic flux density, non-oriented electrical steel sheets and directional electrical steel sheets containing Si and Al to increase specific resistance. Can do.

Next, a water glass origin thing is demonstrated.
In the present invention, water glass containing one or two kinds selected from Na and K and Si is used as a raw material for the insulating coating because it can be painted at room temperature and a smooth surface is easily obtained. Examples of the water glass include sodium silicate and potassium silicate. Conventionally, sodium silicate does not contain particles and can be coated with a thin film, but it has a tendency to peel off without being bonded during annealing, and the core adhesion is insufficient. However, in the present invention, even when sodium silicate is used, the adhesiveness is increased by specifying the content ratio of Si, B, Na, and K contained in the insulating coating, and therefore the core adhesion is insufficient. Thus, sodium silicate can be preferably used.

Next, the oxide particles will be described.
The insulating coating of the present invention contains one or two selected from Na and K and oxide particles containing Si and B in order to develop adhesiveness.
As the oxide particles, it is preferable to use a low melting point glass. The melting point or softening point of the low melting point glass is higher than the temperature at which the iron core is used and lower than the strain relief annealing temperature. For this reason, in the environment which handles a normal iron core, it can be used without a problem without melting or softening, and has the effect of being melted or softened and bonded by strain relief annealing. The composition of the low melting point glass is as follows: R: alkali metal, SiO ₂ -B ₂ O ₃ -R ₂ O system, P ₂ O ₅ -R ₂ O system, SiO ₂ -PbO-B ₂ O ₃ system, B ₂ O ₃ -Bi ₂ O ₃ system, SiO ₂ -B ₂ O ₃ -ZnO system, SnO-P ₂ O ₅ system, SiO ₂ -B ₂ O ₃ -ZrO ₂ system, etc. are raised and selected from these One kind or two or more kinds can be added. Among these, the SiO ₂ —B ₂ O ₃ —R ₂ O system is preferably used because it does not contain lead. However, sufficient core adhesion cannot be obtained simply by using, for example, SiO ₂ —B ₂ O ₃ —R ₂ O-based low-melting glass. As described above, in addition, it is important to specify the content ratio of Si, B, Na, and K contained in the insulating coating.

Area ratio of oxide particles The ratio of the area occupied by the oxide particles to the total area of the insulating coating, that is, the area ratio of the oxide particles is preferably 35% or more and 90% or less. If it is 35% or more, sufficient adhesion to the core can be obtained without insufficient adhesion. If it is 90% or less, peeling due to a decrease in adhesiveness between insulating coatings does not occur, and sufficient core adhesion can be obtained.
The area ratio of the oxide particles can be determined by observing the embedded polishing section, observing the frozen fracture section, or observing the FIB section. A typical value can be obtained by averaging in a range of 40 μm or more in width.

It is important to define the average particle size of the oxide particles in order to make sufficient contact between the insulating coatings of the average particle size of the oxide particles and improve the adhesion.
The average particle diameter of the oxide particles is preferably 0.2 μm or more and 35 μm or less. By setting it to 0.2 μm or more, the effect of the present invention can be further obtained. When the thickness is 35 μm or less, the laminated plate is not peeled off and sufficient core adhesion can be obtained. More preferably, it is 0.3 μm or more and 30 μm or less.
The average particle size can be represented by the particle size of oxide particles as a raw material. Alternatively, in embedded polishing cross-section observation, frozen fracture cross-section observation, and FIB cross-section observation, it is possible to obtain a representative value by measuring the particle diameter of particles dispersed in islands at 10 or more points and averaging them. The shape in the cross section may be various, such as a circle, an ellipse, and a polygon, but the particle diameter can be converted into a circle by calculation from the area to be a representative value.

(Mass of Si contained in insulating coating in terms of SiO ₂ ) / (insulating coating mass) is 0.20 to 0.70.
If it is less than 0.20, sufficient adhesiveness between insulating coatings is not expressed, and adhesion with Si oxide or Al oxide concentrated on the surface of the electrical steel sheet is lowered. When it exceeds 0.70, it becomes difficult to soften at the time of annealing, and the adhesiveness between insulating coatings decreases.

(Mass of terms _{of B} 2 _{O 3} and B contained in the insulating film) / (mass of SiO ₂ in terms of Si contained in the insulating film) is from 0.18 to 1.00
{(Mass of terms of Na ₂ O of Na contained in the insulating film) + (mass of _{K 2} O in terms of K contained in the insulating coating)} / (weight of SiO ₂ in terms of Si contained in the insulating film) is 0 .20-1.00
The inventors of the present invention use a magnetic steel sheet with an insulating coating manufactured by coating a surface treatment of a magnetic steel sheet with a treatment liquid in which SiO ₂ —B ₂ O ₃ —R ₂ O-based low-melting glass and water glass are mixed and baking it. The core adhesion was examined. As a result, it has been found that by specifying the content ratio of Si, B, Na, and K, the core sticking property is improved. In addition, it is understood that the same effect can be seen when a mixture of colloidal silica, etc. added with Na compound, K compound, B compound instead of low melting glass is mixed with water glass and applied to a steel sheet. It was.

  Furthermore, when a plurality of magnetic steel sheets made of a conventional low melting point glass or water glass alone are laminated to form a laminated magnetic steel sheet, peeling is likely to occur during handling such as slitting and punching lamination, while Si, When a plurality of electromagnetic steel sheets with insulating coatings according to the present invention with a specified content ratio of B, Na, and K are laminated to form a laminated electromagnetic steel sheet, it becomes resistant to impact and peels when slitting or punching lamination is performed. I found it difficult.

  The reason for the above is not clear, but I think as follows. Water glass alone has the advantage that it can be painted at room temperature, but has poor adhesion. When the low-melting glass is used alone, there is a high possibility of adhesion, but since it is brittle, it is easily peeled off by impact during handling or punching lamination. On the other hand, low melting point glass, colloidal silica Si-based particles and water glass are mixed in a specific content ratio, which creates a reaction part and takes a sea-island structure, thus suppressing the propagation of cracks due to impact. It is considered that peeling such as floating of the teeth is suppressed.

As a result of the above examination, (mass in terms of B ₂ O ₃ of B contained in the insulating coating) / (mass in terms of SiO _{2 of} Si contained in the insulating coating) is 0.18 to 1.00, {( Na ₂ O equivalent mass of Na contained in the insulating coating) + (mass equivalent to K ₂ O equivalent of K contained in the insulating coating)} / (mass equivalent to SiO _{2 of} Si contained in the insulating coating). It turned out that it has the said effect by setting it as 0.20-1.00.

  In addition, the said component and ratio contained in an insulating film can be known from the mixing ratio at the time of coating liquid preparation. Moreover, it can measure by carrying out ICP analysis of Si, Na, K, and B in a melt | dissolution solution by heating and melt | dissolving an insulating coating film in 20 mass% NaOH aqueous solution. The insulating coating mass can be measured from the change in mass before and after dissolution after dissolving the insulating coating as described above. For laminated electrical steel sheets, it is sometimes difficult to analyze the interlayer, but the interlayer insulating film composition can be represented by the analysis of the outermost insulating film.

It is preferable that an insulating film contains 15 mass% or less of organic resins.
By including an organic resin in the insulating coating, it is possible to further improve the insulating coating performance such as punchability. In the present invention, the organic resin is not particularly limited, and any conventionally known organic resin is advantageously adapted. Examples thereof include aqueous resins (emulsion, dispersion, water-soluble) such as acrylic resin, alkyd resin, polyolefin resin, styrene resin, vinyl acetate resin, epoxy resin, phenol resin, polyester resin, urethane resin, and melamine resin. Particularly preferred is an emulsion of acrylic resin or ethylene acrylic resin.

  Such an organic resin contributes effectively to the improvement of corrosion resistance, scratch resistance and punchability. Moreover, if it is 15 mass% or less in a dry film, there will be no adhesive deterioration by the residue at the time of annealing. For this reason, when it contains organic resin, an upper limit shall be 15 mass%.

  The ratio in the dry film is the ratio of each component (solid content) in the insulating film formed on the surface of the steel sheet. For example, the treatment liquid for forming the insulating film was dried at 180 ° C. for 30 minutes. It can be determined from the remaining components after drying.

  Further, in the present invention, in addition to the above-described components, it does not hinder the inclusion of commonly used additives such as surfactants, rust inhibitors, lubricants, antioxidants, and other inorganic compounds and organic compounds. The organic compound may contain an organic acid as a contact inhibitor between the inorganic component and the organic resin. Examples of the organic acid include a polymer or copolymer containing acrylic acid.

In the present invention, in addition to the above components, each of Al, Ca, Li, F, P, Zn, V, Te, Ge, Ag, Tl, S, I, Br, As, Bi, Cd, and Pb One kind or / and two or more kinds of inorganic compounds such as compounds and pigments, rust preventives and surfactants can be added. Although such an additive can be added to such an extent that the effects of the present invention are not impaired, (additional solid content total mass) / (mass of Si contained in the insulating coating in terms of SiO ₂ ) exceeds 1.0. Then, the unreacted substance remains in the insulating film and lowers the water resistance, so the content is 1.0 or less, preferably 0.5 in terms of (total mass of solid content of additive) / (SiO ₂ converted mass). The following is preferable. Although addition is possible, it may be environmentally preferable not to add As, Bi, Cd, or Pb.

Next, the method for forming the insulating coating of the present invention will be described.
In this invention, it does not prescribe | regulate especially about the pretreatment of the electromagnetic steel plate which is a raw material. That is, although it may be untreated, it is preferably used to perform a degreasing treatment such as alkali or pickling treatment such as hydrochloric acid, sulfuric acid or phosphoric acid.

  And the processing liquid which mix | blended water glass, oxide particle | grains, sodium hydroxide, potassium hydroxide, boric acid, further organic resin, and an additive etc. in the predetermined ratio as needed on the surface of this electrical steel sheet. The insulating coating of the present invention is formed by applying and baking.

  Various methods such as a roll coater, a flow coater, a spray, and a knife coater that are generally used in industry can be applied as a method for applying the insulating coating treatment liquid. In addition, a baking method such as a hot air method, an infrared method, an induction heating method, or the like, which is usually performed, is possible. The baking temperature should just be a normal level, and should just be about 150-350 degreeC by ultimate steel plate temperature.

  Furthermore, a laminated electrical steel sheet can be obtained by laminating and integrating two or more of the electrical steel sheets with an insulating coating obtained as described above via an insulating coating. That is, the coated surfaces of the electromagnetic steel sheets with insulating coatings are superposed and heated and pressed to form a laminated steel sheet, and the surface is further coated to obtain a laminated electromagnetic steel sheet. The heating temperature can be performed in a usual range, for example, 750 ° C. By using such a laminated electrical steel sheet, not only the thin steel sheet with a thickness of 0.30 mm or less is improved in shape retention and handling, but also the number of punches is reduced, greatly increasing productivity. Can be improved. Moreover, since it can be fixed to the iron core after delamination as in the case of a single plate, the magnetic properties can be greatly recovered.

  In this case, the insulating film between the layers of the present invention can be preferably used.

In addition, the electrical steel sheet with an insulating coating of the present invention can be subjected to strain relief annealing to remove, for example, strain due to punching. As a preferable strain relief annealing atmosphere, an atmosphere in which iron is not easily oxidized, such as an N ₂ atmosphere or a DX gas atmosphere, is applied. Here, the dew point is set high, for example, Dp: about 5 to 60 ° C., and the corrosion resistance can be further improved by slightly oxidizing the surface and the cut end face. The preferred strain relief annealing temperature is 700 to 900 ° C, more preferably 700 to 800 ° C. The holding time of the strain relief annealing temperature is preferably longer, but more preferably 1 hour or longer.

  The insulating coating is preferably on both sides of the steel plate. Moreover, it is preferable that it exists in both surfaces of the outermost surface of a laminated electromagnetic steel plate. However, depending on the purpose, only one side may be used. Further, depending on the purpose, only one side may be applied, and the other side may be another insulating film.

  The thickness of the insulating coating of the present invention is not particularly defined, but is preferably 0.1 μm or more and 50 μm or less on average. More preferably, they are 1 micrometer or more and 25 micrometers or less. If it is 0.1 μm or more, the adhesiveness is not lowered, and sufficient core adhesion can be obtained. On the other hand, if it is 50 micrometers or less, a space factor will not fall. In the case of laminated magnetic steel sheets and when bonded by annealing, the thickness of the insulating coating tends to be thinner than a single plate, and the average thickness of the insulating coating between the layers is 0.1 μm or more and 20 μm or less, more preferably 0.5 μm or more and 10 μm. The following is preferred. If it is the said preferable range, it does not matter even if the outermost surface and the insulating film thickness between layers are not uniform.

  Hereinafter, the present invention will be described by way of examples. The present invention is not limited to the following examples.

  The components shown in Tables 2 to 5 were added to deionized water in the proportions shown in Table 1 as the components of the insulating coating, to obtain a treatment solution. In addition, the mass part of a component is an active ingredient except a water | moisture content and a solvent. The total solid concentration of each component with respect to the amount of deionized water was 200 g / l.

  Each of these treatment liquids was applied to both sides of a test piece cut from a magnetic steel sheet having a thickness of 0.20 mm to a width of 150 mm and a length of 300 mm with a bar coater, and the baking temperature (reached by a hot air baking furnace). Steel plate temperature): 200 ° C., baking time: 30 seconds, and then stood to cool to room temperature to form an insulating coating to produce an insulating steel plate with an insulating coating.

  The insulating film characteristics of the electromagnetic steel sheet with the insulating film thus obtained (referred to as product plate in Table 1) were examined.

  Furthermore, the insulating coating film (hereinafter referred to as “annealing plate 1” in Table 1) obtained by performing strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere is applied to the above insulating coating coated electromagnetic steel sheet. The characteristics were investigated.

The evaluation method of each characteristic is as follows.
<Adhesion>
For the product plate and the annealed plate 1, cello tape (registered trademark) was applied to the surface of the test material, the cellotape (registered trademark) was peeled off after bending in φ10 mm, and the remaining state of the insulating coating was visually observed and evaluated.
(Criteria)
◎: Residual rate 90% or more ○: Residual rate 60% or more, less than 90% △: Residual rate 30% or more, less than 60% ×: Residual rate less than 30% <core adhesion>
After shearing 30 × 50 mm electromagnetic steel plates (product plates) with insulating coatings and laminating 100 sheets, strain-relief annealing (750 ° C. × 2 hours in a nitrogen atmosphere) was performed to laminate and fix them. The laminated and fixed sample (annealed plate 2) was dropped onto a steel plate having a height of 1 m to 20 mm, and the peeling state of the sample was visually evaluated.
(Criteria)
◎: No peeling or cracking ○: Crack is observed but no peeling Δ: Separation into 2 to 5 pieces ×: Separation into 6 pieces or more <Punchability>
Using some 15 mmφ steel dies, punching was performed on some insulating steel sheets with insulation coating (annealed plate 1) until the burr height reached 50 μm, and evaluated by the number of punches when the burr height reached 50 μm. did.
(Criteria)
◎: More than 1.2 million times ○: More than 1 million times, less than 1.2 million times ○-: More than 700,000 times, less than 1 million times △: More than 300,000 times, less than 700,000 times ×: Less than 300,000 times The results are shown in Table 1 together with the conditions.

  As shown in Table 1, all of the electrical steel sheets with insulating coatings obtained according to the present invention were excellent in adhesion and core adhesion. Furthermore, even when the motor core was punched out and subjected to strain relief annealing, the teeth were not peeled off and lifted up, and a good product was obtained.

  On the other hand, the comparative example was inferior to adhesiveness and core sticking property. Furthermore, when the motor core was punched out and subjected to strain relief annealing, a large number of teeth were peeled off and lifted up.

Thickness of two laminated steel sheets: 0.20 mm of electromagnetic steel sheet, an insulating film composed of the components shown in Table 1, Example 3 is barred so that the dry film weight is 10 g / m ² on each side. After coating with a coater and baking in a hot air baking oven (attained steel plate temperature): 200 ° C., baking time: 30 seconds, the coated surfaces are bonded together, and then annealed in a nitrogen atmosphere at 750 ° C. for 2 hours. Two laminated steel sheets were obtained. Furthermore, an insulating coating composed of the components shown in Table 1 Example 3 was applied to both surfaces (front and back surfaces) of the two-layer laminated steel sheet with a bar coater so as to have a dry coating weight of 10 g / m ^2, and the baking temperature ( Achieving steel sheet temperature): 200 ° C., baking time: 30 seconds was baked to produce a two-layer laminated electrical steel sheet capable of annealing adhesion.
A punching test similar to that of Example 1 was performed on the above-mentioned two laminated electromagnetic steel sheets. As a result, the punching time was punched at the same speed in order to produce the same iron core with one non-laminated electromagnetic steel sheet. It was cut in half.
Furthermore, when the same core adhesion test as in Example 1 was performed, there was no peeling and cracking, and sufficient adhesion was obtained.

Three laminated steel plate thickness: An insulating coating consisting of the components shown in Example 3 in Table 1 is applied to one sheet of 0.20 mm electromagnetic steel plate with a bar coater so that the dry coating weight is 20 g / m ² on each side. Then, it was baked in a hot air baking furnace at a baking temperature (attained steel plate temperature): 200 ° C. and baking time: 30 seconds. Three sheets of electromagnetic steel sheets with insulating coating are laminated between two uncoated (not having insulating coating) magnetic steel sheets and annealed at 750 ° C. for 2 hours in a nitrogen atmosphere. A steel plate was used. Furthermore, an insulating coating composed of the components shown in Table 1 Example 24 was applied to both surfaces (front and back surfaces) of this three-layer laminated electrical steel sheet with a bar coater so as to have a dry coating weight of 10 g / m ^2. Baking temperature (attained steel plate temperature): 200 ° C., baking time: 30-sec.
A punching test similar to that in Example 1 was performed on the above three laminated electromagnetic steel sheets. As a result, the punching time was punched at the same speed in order to produce the same iron core with one non-laminated electromagnetic steel sheet. It was shortened to 1/3 of that.
Furthermore, when the same core adhesion test as in Example 1 was performed, there was no peeling and cracking, and sufficient adhesion was obtained.

Claims (5)

A magnetic steel sheet containing a component made of water glass and oxide particles, and having an insulating film containing 15% by mass or less of an organic resin on at least one side,
The component using the water glass as a raw material contains one or two selected from Na 2 and K, and Si.
The oxide particles contain one or two selected from Na and K, and Si and B.
The insulating coating is
(The mass of Si contained in the insulating coating in terms of SiO ₂ ) / (insulating coating mass) is 0.20 to 0.70,
(Mass in terms of B ₂ O ₃ of B contained in the insulating coating) / (mass in terms of SiO _{2 of} Si contained in the insulating coating) is 0.18 to 1.00,
{(Mass of Na contained in the insulating coating in terms of Na ₂ O) + (Mass of K in the insulating coating in terms of K ₂ O)} / (Mass of Si in the insulating coating in terms of SiO ₂₎ ) Is 0.20 to 1.00. An electrical steel sheet with an insulating coating. 2. The electrical steel sheet with an insulating coating according to claim 1, wherein an area ratio of the oxide particles is 35% or more and 90% or less.
The area ratio of the oxide particles is the ratio of the area occupied by the oxide particles to the total area of the insulating coating, and the area occupied by the oxide particles is embedded polishing cross-section observation, frozen fracture cross-section observation, or FIB cross-section. It can be determined by observation.   3. The electrical steel sheet with an insulating coating according to claim 1, wherein an average particle diameter of the oxide particles is 0.2 μm or more and 35 μm or less.   The electrical steel sheet with an insulating coating according to any one of claims 1 to 3, wherein the oxide particles are low-melting glass. Superposing the coated surfaces of the insulation coating with an electromagnetic steel sheet according to any one of claims 1-4, or painted surfaces of the insulating coating with an electromagnetic steel sheet according to claim 1 A laminated electrical steel sheet in which two or more magnetic steel sheets that do not have an insulating coating are stacked and integrated.