JP4890387B2 - Manufacturing method and manufacturing apparatus for grain-oriented silicon steel sheet - Google Patents

Description

  The present invention provides a direction in which an insulating coating with good adhesion to a metal can be formed when a groove is formed by electrolytic etching on the surface of a directional silicon steel sheet that has been subjected to finish annealing. The present invention relates to a method and an apparatus for producing a porous silicon steel sheet.

  Conventionally, a surface of a directional silicon steel sheet is formed by applying an etching pattern to the insulating film by means such as removing a part of the insulating film formed on the surface of the directionally annealed directional silicon steel sheet, and etching along the etching pattern. For example, Patent Document 1 discloses a technique for improving the iron loss characteristic of a grain-oriented silicon steel sheet by selectively performing grooving. This technique is advantageous because the iron loss improvement effect by groove processing does not disappear even by subsequent strain relief annealing, and in recent years, groove processing as shown in Patent Documents 2 and 3 is continuously performed by electrolytic etching. Technology has also been proposed.

  Patent Document 2 discloses an etching apparatus that performs continuous electrolysis in a direct energization method. As shown in FIG. 2, this apparatus is an electrolytic etching apparatus for a metal strip 1 having an electrically insulating insulating film selectively applied on one side, and includes an electrolytic etching tank 2, a conductor roll 16 serving as an anode, The backup roll 17 disposed so as to be in contact with the conductor roll 16 with the metal strip 1 interposed therebetween, the cathode electrode 15 immersed in the electrolytic solution 3 of the electrolytic etching tank 2, and the metal strip 1 with the electrolytic solution 3 and dipping rolls 13 and 14 for dipping in 3.

  In this apparatus, the surface of the metal strip 1 on which the insulating coating is applied is passed downward, the cathode electrode 15 faces upward and faces the insulating coating surface of the metal strip 1, and the insulating coating surface. The conductor roll 16 is brought into contact with the surface of the metal strip 1 where the insulating coating is not applied, and the backup roll 17 is brought into contact with the insulating coating surface of the metal strip 1. It is arranged like this. Conductor roll 16 and cathode electrode 15, which are anodes, are connected to DC power supply device 7 and selectively subjected to electrolytic etching by direct energization of metal strip 1. Moreover, the conductor roll 16 is arrange | positioned on the outer side of the electrolyte solution 3 of the electrolytic etching tank 2, and generation | occurrence | production of a short circuit current is prevented.

  Patent Document 3 discloses an etching method and apparatus for continuous electrolysis in an indirect energization method. As shown in FIG. 3, the apparatus is provided with electrodes 4 and 5 in the traveling direction of the metal band 1 opposite to the etching surface of the metal band 1 with an insulating film selectively formed on one surface. In addition, the electrolytic solution 3 is filled between the metal strip 1 and the electrodes 4 and 5, and the DC power supply devices 7 and 8 are disposed between the electrodes 4 and 5. A switch 9 is installed between the DC power supply 7 and the electrode 4, a switch 10 is installed between the DC power supply 8 and the electrode 4, and a switch 9 is installed between the DC power supply 7 and the electrode 5. However, a switch 10 ′ is installed between the DC power supply 8 and the electrode 5 and selectively subjected to electrolytic etching by indirect energization. In addition, a shielding plate 6 made of a nonconductive material is installed between the electrode 4 and the electrode 5 for the purpose of suppressing a leakage current that flows directly between the electrode 4 and the electrode 5 via the electrolytic solution 3. .

  In the etching, by operating the switches 9, 9 ', 10, 10' installed between the electrodes 4 and 5, as shown in FIG. On the other hand, a voltage at which the direction of current flow is reversed and the electrode 4 becomes a cathode is temporarily applied. By applying a reverse voltage, the etching groove shape is controlled so as to obtain the target shape as shown in FIG. 5A, and the occurrence of the groove shapes shown in FIGS. ing.

JP-A-63-76819 Japanese Patent Laid-Open No. 10-204699 JP 2004-131841 A WO03 / 048416

When the surface of a grain-oriented silicon steel sheet is grooved by etching as shown in Patent Documents 1 to 3, it is necessary to further form an insulating film on the steel sheet surface after etching. The literature does not specifically describe the adhesion of the insulating coating to the metal.
In particular, the present inventors have carried out electrolytic etching in order to collect basic data on the adhesion of the insulating film to the steel sheet grooved by electrolytic etching as shown in Patent Documents 2 and 3. An insulating film was applied to the film, and the adhesion of the insulating film to the base metal was evaluated.

  As a result, compared to the steel material that was not subjected to electrolytic etching, in the steel sheet that was subjected to electrolytic etching, the adhesive strength of the insulating coating tends to decrease, and in particular, when the adhesive strength of the insulating coating that covers the groove portion decreases, In subsequent processing steps, it was found that the insulating coating dropped from the surface of the steel sheet during the passing of the steel sheet, which caused problems such as damage to the steel sheet and deterioration of product quality.

  Therefore, the present invention makes it possible to obtain a grain-oriented silicon steel sheet capable of obtaining adhesion of an insulating coating similar to that of a steel material that has not been subjected to electrolytic etching to a base metal even in a steel material that has been subjected to electrolytic etching. It is an object of the present invention to provide a method and an apparatus for producing a directional silicon steel sheet that solves such a problem.

The inventors of the present invention have a tendency to reduce the adhesion because the surface of the groove is smooth and the insulating coating formed in the groove becomes thicker in the steel sheet subjected to electrolytic etching. I found it. And, if the film with good adhesion to the base metal can be selectively formed in the groove part, it is thought that the adhesion with the insulating film is improved through the base film, and further, following the electrolytic etching, The means for continuously forming a film at a processing rate equivalent to that of electrolytic etching was investigated.
As a result, the present inventors paid attention to the film formation technique by electrolytic treatment described in Patent Document 4 as satisfying the above conditions.

  The technique described in Patent Document 4 includes (1) a fluorine ion having a molar ratio of 4 times or more with respect to a metal ion and an approximately metal ion, and / or (2) a metal ion and the metal ion. A metal material containing at least a complex ion to which a fluorine-containing compound having a molar ratio of 4 times or more is bonded and having a pH of 3 to 7 is immersed in a treatment solution or electrolyzed with a conductive material. This is a technique for forming a metal oxide and / or metal hydroxide film containing the metal ions on the surface.

  The inventors of the present invention described in Patent Document 4 previously formed a metal oxide or metal hydroxide film on the groove part before forming the insulating film, thereby forming the groove part. It has been found that the adhesion to the insulating coating on the surface is improved, and that a steel sheet that has been subjected to electrolytic etching can have an adhesion equal to or higher than that of a steel material that has not been subjected to electrolytic etching.

The gist of the present invention made based on the above findings is as follows.
(1) A directional silicon steel sheet in which one side or both sides of a directional silicon steel sheet that has been annealed and has an insulating coating on its surface is continuously grooved by electrolytic etching, and then an insulating coating is formed on the grooved surface. And (1) metal ions and fluorine ions at a molar ratio of 4 times or more with respect to the metal ions, between each step of the groove processing by the electrolytic etching and the subsequent formation of the insulating film, And / or (2) in a post-treatment aqueous solution having a complex ion in which at least a compound containing fluorine at a molar ratio of 4 times or more with respect to the metal ion and the metal ion is bonded and having a pH of 3 to 7. Applying a voltage by energizing the grain-oriented silicon steel sheet, and forming a metal oxide coating and / or metal hydroxide coating containing the metal ions on the surface of the grooved portion. Yes Method for producing a grain-oriented silicon steel sheet characterized by Rukoto.
(2) The energization for applying a voltage to the directional silicon steel sheet in the metal compound coating forming step is indirect energization by an electrode disposed opposite to the etching surface of the directional silicon steel sheet in the post-treatment aqueous solution. The electrodes are arranged such that electrodes having different polarities are alternately arranged in the traveling direction of the grain-oriented silicon steel sheet so that the most downstream electrode serves as an anode, and a voltage is applied between the cathode and the anode electrode. The method for producing a grain-oriented silicon steel sheet according to (1) above, wherein

(3) An apparatus for carrying out the method for producing a grain-oriented silicon steel sheet according to (1) above, wherein one or both surfaces of a grain-oriented silicon steel sheet having a finish annealing and having an insulating coating on the surface are continuously etched by electrolytic etching. And (1) containing fluorine ions at a molar ratio of 4 times or more with respect to metal ions and approximately metal ions, and / or (2) with respect to metal ions and the metal ions. In addition, a voltage is applied to the post-treatment tank containing a complex ion to which at least a compound containing fluorine at a molar ratio of 4 times or more is bound and having a pH of 3 to 7 and filled with a post-treatment aqueous solution and the grain-oriented silicon steel sheet. There is provided a post-processing apparatus that has an electrode and continuously forms a film of the metal oxide and / or metal hydroxide containing the metal ions on the etched surface of the grain-oriented silicon steel sheet in the post-treatment aqueous solution. That Apparatus for producing a grain-oriented silicon steel sheet according to symptoms.
(4) The electrode is composed of a plurality of electrodes having different polarities from each other, arranged in the post-treatment aqueous solution so as to be opposite to each other and opposite to the etching surface of the directional silicon steel sheet, and the most downstream electrode Is disposed as an anode, a shielding plate made of a non-conductive material is disposed between adjacent electrodes, and energization for applying a voltage to the directional silicon steel plate is performed by the electrode. The directional silicon steel sheet manufacturing apparatus according to (3) above, wherein the directional silicon steel sheet is manufactured by indirect energization.

  According to the present invention, even in a directional silicon steel sheet that has been grooved by electrolytic etching, it becomes possible to obtain adhesion equal to or better than that of a steel sheet that has not been subjected to electrolytic etching, and is used for an iron core of a power transformer and the like. Since generation | occurrence | production of the damage | wound etc. which generate | occur | produce by the insulating film which fell during the passage of the low iron loss directional silicon steel plate can be prevented, the quality and yield of a product improve. Moreover, since the post-treatment process can be carried out continuously by electrolytic treatment in the same manner as the etching process, it is excellent in terms of productivity.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 schematically shows equipment according to an embodiment of the present invention. An electrolytic etching apparatus 20 for etching the surface of a directional silicon steel sheet 1 that has been subjected to finish annealing and a metal compound on the surface after etching. A post-processing device 40 for forming the coating is continuously arranged.

The grain-oriented silicon steel sheet 1 is selectively formed with an insulating film, or the surface insulating film is selectively removed by laser processing or the like after finish annealing, and a predetermined etching mask pattern is formed in advance. Yes. In the surface etching apparatus 20, groove processing is performed along the etching pattern by electrolytic etching of such a directional silicon steel sheet. In the post-processing apparatus 40, post-treatment is performed on the surface of the directional silicon steel sheet after the etching process. A metal oxide and / or metal hydroxide film containing metal ions dissolved in an aqueous solution is formed.
In addition, although the insulating film formation processing apparatus for apply | coating and baking an insulating film on a directional silicon steel plate is arrange | positioned in the downstream of the post-processing apparatus 40, it is abbreviate | omitted in the figure.

  In the etching apparatus 20, the electrodes 4 and 5 are installed in the traveling direction of the directional silicon steel plate 1 so as to face the etching surface of the directional silicon steel plate 1, and between the directional silicon steel plate 1 and the electrodes 4 and 5. The electrolyte solution 3 is filled in, and a DC power supply device 7 and a DC power supply device 8 are disposed between the electrode 4 and the electrode 5. A switch 9 is installed between the DC power supply 7 and the electrode 4, a switch 10 is installed between the DC power supply 8 and the electrode 4, and a switch 9 is installed between the DC power supply 7 and the electrode 5. 'And a resistor 22, and a switch 10 ′ and a resistor 23 are installed between the DC power supply 8 and the electrode 5, and electrolytic etching is performed by indirect energization. In addition, a shielding plate 6 made of a nonconductive material is installed between the electrode 4 and the electrode 5 for the purpose of suppressing a leakage current that flows directly between the electrode 4 and the electrode 5 via the electrolytic solution 3. .

When etching the grain-oriented silicon steel sheet, the voltage between the electrodes 4 and 5 is such that the direction of current flow is reversed as shown in FIG. 4 by operating the switches 9, 9 ', 10, 10'. Is temporarily applied. Further, the voltage applied to the electrode 4 between the electrode 4 and the electrode 5 is increased / decreased by increasing / decreasing the resistors 22, 23.
Accordingly, for example, the negative application time to the electrode 4 is set to 3 to 7 msec, the positive application time is set to 12 to 200 msec, and there is little variation in the groove shape, and the groove shape as shown in FIG. To be.

In the case where the electric resistance of the electric circuit of electrolytic etching does not change, it is assumed that the control of the energization amount per unit time can be replaced by voltage control.
Further, ringer rolls 11 and 22 are installed on the entry / exit side of the electrolytic cell 2 as conveyance rolls for the directional silicon steel sheet 1 to suppress the outflow of the electrolytic etching solution 3 to the outside of the cell. Sink rolls 13 and 14 are installed in the tank, and the distance between the cathode electrode 4 and the anode electrode 5 and the directional silicon steel sheet 1 is kept constant.

  The grain-oriented silicon steel sheet 1 that has been grooved by the etching apparatus 20 is subsequently conveyed to the post-processing apparatus 40. In the post-processing apparatus 40, the cathode electrode 34 and the anode electrode 35 are sequentially installed facing the etching surface of the directional silicon steel plate 1 toward the downstream side in the traveling direction of the directional silicon steel plate 1. A post-treatment aqueous solution 33 is filled between the cathode electrode 34 and the anode electrode 35, and a DC power supply device 37 is disposed between the cathode electrode 34 and the anode electrode 35.

  A switch 39 is installed between the DC power supply device 37 and the cathode electrode 34 to form a metal oxide film by indirect energization. In addition, a non-conductive material is provided in the post-treatment tank 32 between the anode electrode 35 and the cathode electrode 34 for the purpose of suppressing leakage current that flows directly from the anode electrode 35 to the cathode electrode 34 via the post-treatment aqueous solution 33. The shielding board 36 which consists of is installed. A resistor 52 is installed between the DC power supply device 37 and the anode electrode 35.

  A voltage is applied between the cathode electrode 34 and the anode electrode 35 by closing the switch 39. The voltage application is interrupted by opening the switch 39. Further, by increasing / decreasing the resistance 52, the negative voltage applied to the cathode electrode 34 between the cathode electrode 34 and the anode electrode 35 is increased / decreased. In the case where the electric resistance of the electric circuit for forming the metal oxide film does not change, it is assumed that the control of the energization amount per unit time can be replaced by voltage control.

  In addition, ringer rolls 41 and 42 are installed on the entry / exit side of the post-treatment tank 32 as conveying rolls of the directional silicon steel sheet 1 to suppress the outflow of the post-treatment aqueous solution 33 to the outside of the tank. Sink rolls 43 and 44 are installed in the tank, and the distance between the cathode electrode 34 and the anode electrode 35 and the directional silicon steel sheet 1 is kept constant.

The post-treatment aqueous solution 33 is
(1) Metal ions and fluorine ions at a molar ratio of 4 times or more with respect to the metal ions,
(2) a complex ion in which a metal ion and a compound containing fluorine at a molar ratio of 4 times or more with respect to the metal ion are combined;
These are one or two of the above, and are composed of an aqueous solution having a pH of 3 to 7.

  If the pH of the post-treatment aqueous solution is less than 3, inhibition of the formation of the base film due to hydrogen generation is likely to occur, and if it is greater than 7, the aggregate in the aqueous solution is precipitated and the adhesion is not improved. 3-7 are desirable.

  Ti and Si are preferable as the metal ions and the metal constituting the complex ions. However, the metal ions are not limited thereto, and complex ions in which fluorine-containing compounds such as Zr, Fe, Sn, and Nd are at least bonded. The metal which forms may be sufficient.

  The fluorine ion used in the present invention includes hydrofluoric acid or a salt thereof such as ammonium salt, potassium salt, sodium salt and the like. There are no particular restrictions on these, but when a salt is used, its catechin is used. Since the degree of saturated solution varies depending on the species, it may be necessary to select a film concentration range in consideration.

  The anode electrode 35 is preferably made of a metal that releases metal ions that promote the decomposition of the complex ions, and Al is desirable for this purpose. Further, from the viewpoint of reducing the electric field voltage, the cathode electrode 34 is generally desirable to have a small hydrogen overvoltage, such as Pt.

  In the post-processing apparatus 40 as described above, a negative voltage is applied to the cathode electrode 34 between the cathode electrode 34 and the anode electrode 35. As a result, a predetermined electrolytic current adjusted in advance flows from the anode electrode 35 to the directional silicon steel plate 1 through the post-treatment aqueous solution 33 facing the electrode and the etching groove portion (which becomes a cathode) of the directional silicon steel plate 1. In addition, it flows to the cathode electrode 34 through the etching groove portion (to be an anode) of the directional silicon steel sheet 1 facing the cathode electrode 34 and the post-treatment aqueous solution 33.

Due to this electrolytic current, the voltage applied to the cathode electrode 34 is a negative voltage application, and the anodic reaction Me → Me ⁺ is applied to the etching groove portion (which becomes the anode) of the directional silicon steel sheet 1 on the side facing the cathode electrode 34. + E ⁻ (When the metal strip is a steel strip, Fe → Fe ² + 2e ⁻ )
As a result, electrolytic etching proceeds.

In the cathode electrode 34, the cathode reaction (electron acceptance reaction)
_{^{2H + + 2e - → H 2}} ↑
As a result, H ₂ gas is generated.

On the other hand, in the etching groove portion of the directional silicon steel sheet 1 on the side facing the anode electrode 35, a metal oxide or hydroxide is precipitated from a metal complex ion bonded with a fluorine-containing compound by a cathode reaction. When the metal is a complex ion of Ti, H ₂ TiF ₆ + 2H ₂ O → TiO ₂ + 6HF
As a result, TiO ₂ is deposited in the etching groove of the directional silicon steel sheet 1.

Further, in the anode electrode 35, the anode reaction Me → Me ⁺ + e ⁻ (when the electrode is Al, Al → Al ³⁺ + 3e ⁻ )
As a result, dissolution of the metal electrode proceeds.
In the treatment aqueous solution of the post-treatment tank 33,
Al ³⁺ + 6HF → H ₃ AlF ₆ + 3H ⁺
And the reaction continues.

The energization amount per unit time of the voltage application for continuing the above reaction is about several C / dm ² . This is because a very thin metal oxide is sufficient for improving the adhesion of the insulating coating to the ground iron.
The electrolytic power supply device used for the post-treatment device may be of any system as long as the voltage application can be performed. For example, a 6-phase half-wave rectified waveform of a transistor system or an inverter system is effective. Moreover, it is not always necessary to install a single resistor, and any method can be used as long as the amount of voltage application can be controlled.

By passing the post-processing apparatus as described above, for example, TiO ₂ is deposited in the etching groove portion of the grain-oriented silicon steel sheet 1, and the base metal surface exposed by etching is covered with a thin metal oxide film (oxide film). Is called. Thereafter, an insulating film such as a tension-imparting film (phosphoric acid-based insulating film) is formed on the directional silicon steel sheet. At this time, the oxide film intervenes between the surface of the ground iron and the insulating film. The adhesion of the insulating coating to the directional silicon steel sheet surface is improved to be equal to or higher than that of the unetched surface.

  The film formed in the metal compound coating formation step is not limited to the metal oxide as described above, and it is possible to form a film in the same manner even in the case of a metal hydroxide film. Can be improved.

In the above embodiment, an example in which etching processing is performed on one surface of a directional silicon steel sheet and coating processing is performed on the etching processing surface has been described, but an insulating film is formed on both surfaces of a steel sheet etched on both surfaces. The same can be done even when doing.
In the case of processing the surfaces on both sides, in the apparatus shown in FIG. 1, both the etching unit 20 and the post-processing unit 40 have the electrode part and the power supply unit part on the upper surface side of the directional silicon steel sheet 1 as well as the lower surface side. It is possible by arranging.

  Moreover, in the above embodiment, although the indirect energization was demonstrated as the energization method to the grain-oriented silicon steel plate 1, it is not limited to indirect energization, Etching and film formation are possible also by direct energization. Of course.

When the coating is formed by direct energization, a voltage is applied so that the directional silicon steel plate 1 serves as a cathode and the electrode serves as an anode. Thereby, in the etching groove part of the grain-oriented silicon steel sheet 1, a metal oxide or a hydroxide precipitates from the metal complex ion to which the fluorine-containing compound is bonded.
When the metal is a complex ion of Ti, H ₂ TiF ₆ + 2H ₂ O → TiO ₂ + 6HF
As a result, TiO ₂ precipitates in the groove portion of the grain-oriented silicon steel sheet 1.

Further, in the electrode section, an anodic reaction Me → Me ⁺ + e ⁻ (when the electrode is Al, Al → Al ³⁺ + 3e ⁻ )
As a result, dissolution of the metal electrode proceeds.
In the treatment aqueous solution in the post-treatment tank,
Al ³⁺ + 6HF → H ₃ AlF ₆ + 3H ⁺
And the reaction continues.

Further, in the above embodiment, an example in which a pair of electrodes composed of an anode and a cathode is provided for both the etching apparatus 20 and the post-processing apparatus 40 has been described. However, a plurality of pairs of electrodes are continuously provided. Thus, the processing speed can be further increased.
In that case, the most downstream electrode is arranged to be a cathode in the etching apparatus and to be an anode in the post-processing apparatus.

In addition, the grain-oriented silicon steel plate to which the present invention is applied is not limited to a steel plate on which forsterite (Mg ₂ SiO ₄ ) is formed, but a tension-imparting coating (phosphoric acid-based insulation) on the surface not having forsterite. The effect is effective even in a grain-oriented silicon steel sheet in which the film) is selectively coated or the tension-imparting film coated on the entire surface is selectively removed.

  Hereinafter, based on an Example, the feasibility and effect of this invention are demonstrated concretely.

A steel sheet cold-rolled to the final thickness using a material for grain-oriented silicon steel sheets is prepared, and after the steel sheet is decarburized and annealed, an annealing separator made of MgO is applied and dried on both surfaces. Further, finish annealing is performed, and a tension-imparting coating (phosphate insulating coating) is applied and baked on the forsterite (Mg ₂ SiO ₄ ) coating formed on both surfaces during the finish annealing, and directional silicon A steel plate was prepared. Thereafter, before electrolytically etching the steel sheet, the forsterite coating and the tension-imparting coating were selectively removed from the surface on one side by a laser beam to form an etching pattern. Since this tension-imparting film is an electrically insulating film, it was used as an etching mask.

The grain-oriented silicon steel sheet subjected to the pretreatment as described above was subjected to electrolytic etching treatment and metal oxide film formation treatment using the indirect energization type continuous electrolytic treatment apparatus shown in FIG. In the film-forming treatment, a post-treatment aqueous solution (A) having a pH of 3 to 7 and containing a complex ion in which a metal ion and a compound containing fluorine at a molar ratio of 4 times or more with respect to the metal ion are combined, and (B) Inside, a metal oxide film was formed.
Specific conditions at that time are shown below.

[Directional silicon steel sheet] Thickness 0.22 mm, width 1000 mm
[Insulating coating] It has an etching pattern with a pitch of 3 mm and a width of 0.2 mm in a direction perpendicular to the longitudinal direction of the steel strip (steel strip width direction).
[Etching Electrolyte] Composition 500 g-NaCl / l, liquid temperature 60 ° C.
[Etching target groove depth] 0.02 mm
[Etching Electrolytic Current] 350 C / dm ²
[Post-treatment aqueous solution]
Liquid A: Composition (NH ₄ ) ₂ TiF ₆ 0.02M
(Ti: F (molar ratio) = 1: 6)
Liquid temperature 60 ℃
Solution B: Composition _{TiCl 4 0.02M, (NH 4)} HF 2 0.06M
(Ti: F (molar ratio) = 1: 6)
Liquid temperature 60 ℃
Solution C: Composition _{(NH 4)} 2 _TiF 6 0.01M
TiCl ₄ 0.01M, (NH ₄ ) HF ₂ 0.03M
(Ti: F (molar ratio) = 1: 6)
Liquid temperature 60 ℃
[Post-treatment anode material] Al
[Post-treatment electrolytic current] 2C / dm ²

  After the electrolytic etching, samples at various speeds were taken, and the variation in the shape pattern of the groove formed by the electrolytic etching in the width direction of the steel strip and the depth of the groove were evaluated. In addition, after the electrolytic etching treatment and the post-treatment (metal oxide film formation), an insulating film was applied, and the adhesion to the steel sheet (peeling test by attaching to a φ20 bar) was evaluated.

Table 1 shows test conditions and results when voltage is applied to the grain-oriented silicon steel sheet using the apparatus shown in FIG. In addition, the shape of the groove | channel classified the shape of the groove | channel after an etching into (A)-(D) based on FIG. 5, and each presence ratio was shown by%.
No. 1-5, no. 11-15, no. 21-25 and No. In the etching examples according to the present invention shown in 31 to 36, the shape of the groove is all stable in (a), and the groove depth variation (%) ((standard deviation of groove depth) / ( It can be seen that the average value of the groove depth) × 100) is also very small. Furthermore, the metal oxide film was formed using the post-treatment aqueous solution (A). 1-5, No. 1 in which the metal oxide film was formed with the post-treatment aqueous solution (B). No. 21 to 25, and No. 1 in which a metal oxide film was formed with the treatment liquid (C). Nos. 31 to 36 were No. which did not perform metal oxide film formation. Compared with 11-15, the film adhesion to the metal was good (no peeling in the bending test).
In addition, No. Reference numerals 6 to 10 are reference examples in which no coating was formed because the distribution of the positive and negative voltage application time to the electrode 4 was not appropriate and the groove having the shape (a) could not be stably formed.

According to an embodiment of the present invention, a metal strip having an insulating film provided with an etching pattern on one surface is continuously grooved by an indirect energization electrolytic etching and continuously by an indirect energization method. It is a schematic explanatory drawing by the longitudinal direction vertical sectional view of the apparatus which forms the metal oxide film in a groove part. It is a figure explaining the outline of the conventional direct current | flow type continuous electrolytic etching apparatus of a metal strip with a longitudinal direction vertical sectional view. It is a figure explaining the outline of the conventional indirect energization type continuous electrolytic etching apparatus of a metal belt with a longitudinal direction vertical sectional view. It is a figure which shows the example of a voltage application between the electrode 4 and the electrode 5 based on one embodiment of this invention. It is a figure which classify | categorizes and shows the pattern of the cross-sectional shape of the groove | channel formed by electrolytic etching.

Explanation of symbols

1 Metal strip 2 Electrolytic tank (electrolytic etching tank)
3 Electrolytic etching solution 4, 5 Electrode 6, 36 Shield plate (non-conductive material)
7, 8, 37 DC power supply 9, 10, 9 ', 10', 39 Switch 11, 12, 41, 42 Ringer roll 13, 14, 43, 44 Sink roll (dipping roll)
15 Cathode electrode 16 Conductor roll 17 Backup roll 22, 23, 52 Resistance 32 Post-treatment tank (metal oxide film formation tank)
33 Post-treatment aqueous solution 34 Cathode electrode 35 Anode electrode 20 Etching device 40 Post-treatment device

Claims (4)

A method for producing a directional silicon steel sheet, wherein one or both surfaces of a directional silicon steel sheet that is finish-annealed and has an insulating film on its surface is continuously grooved by electrolytic etching, and then an insulating film is formed on the grooved surface. Because
Between each step of the groove processing by the electrolytic etching and the subsequent formation of the insulating film, (1) metal ions and fluorine ions at a molar ratio of 4 times or more with respect to the metal ions and / or (2) In the post-treatment aqueous solution having a complex ion in which a metal ion and a compound containing fluorine at a molar ratio of 4 times or more with respect to the metal ion are bonded and having a pH of 3 to 7, a voltage is applied to the grain-oriented silicon steel plate. A grain-oriented silicon steel sheet characterized by having a metal compound coating forming step of applying and forming a film of the metal oxide and / or metal hydroxide containing the metal ions on the surface of the grooved portion Manufacturing method.   The energization for voltage application to the directional silicon steel sheet in the metal compound coating forming step is indirect energization with an electrode disposed opposite to the etching surface of the directional silicon steel sheet in the post-treatment aqueous solution, The electrodes are arranged such that electrodes having different polarities are alternately arranged in the traveling direction of the grain-oriented silicon steel sheet so that the most downstream electrode serves as an anode, and a voltage is applied between these cathode and anode electrodes. The method for producing a grain-oriented silicon steel sheet according to claim 1, characterized in that: An apparatus for carrying out the method for producing a grain-oriented silicon steel sheet according to claim 1,
Next to an etching apparatus that performs continuous groove processing by electrolytic etching on one or both sides of a directional silicon steel sheet that has been annealed and has an insulating coating on its surface, (1) a molar ratio of 4 to metal ions and approximately metal ions. And / or (2) a complex ion in which at least a metal ion and a compound containing fluorine at a molar ratio of 4 or more with respect to the metal ion are bonded to each other, and the pH is 3 to 7 A metal oxide containing a post-treatment tank filled with a post-treatment aqueous solution and an electrode for applying a voltage to the grain-oriented silicon steel sheet, and containing the metal ions on the etching surface of the grain-oriented silicon steel sheet in the post-treatment aqueous solution An apparatus for producing a grain-oriented silicon steel sheet, wherein a post-treatment device for continuously forming a metal hydroxide film is provided.   The electrodes are composed of a plurality of electrodes having different polarities from each other, arranged in the post-treatment aqueous solution so as to be opposite to each other and opposite to the etching surface of the grain-oriented silicon steel sheet, and the most downstream electrode is an anode. A shielding plate made of a non-conductive material is arranged between adjacent electrodes, and energization for applying voltage to the directional silicon steel plate is performed indirectly by the electrodes. The directional silicon steel sheet manufacturing apparatus according to claim 3, wherein

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