JP2005226135A - Direct energizing type continuous electrolytic etching method and direct energizing type continuous electrolytic etching apparatus for metallic strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide direct energizing type continuous electrolytic etching method and apparatus for a metallic strip which realize stable treatment even under the condition of an electrolytic solution in which turbidity is increased by long time treatment. <P>SOLUTION: In the etching method, one or more sets of a B system electrode arranged opposite to the etching face of a metallic strip and of an A system conductor roll pairing with the electrode are arranged in succession, and successively to the final one thereof, a set of an A' conductor roll and a B' electrode are arranged. An electrolytic solution is filled into the space between the metallic strip and each electrode, and each conductor roll is brought into contact with the other surface. Between the A system conductor roll and the B system electrode, (I) voltage application in which the B system electrode functions as an anode and (II) voltage application in which the B system electrode functions as a cathode are alternately repeated. Also, the time in which voltage is not applied to the space between the A system and B system electrodes is inserted when the voltage application is shifted from (I) to (II) and when shifted from (II) to (I). Further, voltage application in which the B' electrode functions as the cathode is performed to the space between the A' conductor roll and the B' electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a metal strip direct energization type continuous electrolytic etching method and a direct energization type continuous electrolytic etching apparatus, and in particular, the metal strip is subjected to electrolytic etching continuously for a long time, so that the amount of dissolved metal in the electrolyte increases. The present invention relates to a direct energization type continuous electroetching method and a direct energization type continuous electroetching apparatus for a metal strip, which are capable of performing stable electroetching.

  By selectively forming an etching mask (etching resist) that is electrically insulating on a metal band such as a steel band (with an etching pattern), and continuously machining grooves by electrolytic etching, the material properties of the metal band As an example of the prior art for improving the invention, the invention of a method for producing a low iron loss directional electrical steel sheet suitable for use as an iron core of a transformer or other electric device disclosed in Patent Document 1, Patent Document 2, etc. There are examples.

An outline of a conventional metal strip direct energization type continuous electrolytic etching apparatus will be described below by taking the invention disclosed in Patent Document 3 as an example. That is, as shown in FIG. 7, the apparatus is an electrolytic etching apparatus for a metal strip 1 having an electrically insulating etching resist on one side, and includes an electrolytic etching tank 2 ″ and a conductor roll 13 ″ as an anode. , 14 ″, backup rolls 19 and 20 disposed so as to be in contact with the conductor rolls 13 ″ and 14 ″ with the metal strip 1 interposed therebetween, and an electrolytic solution 3 ″ in an electrolytic etching bath 2 ″. A negative electrode 5 ″ and dipping rolls 11 and 12 for immersing the metal strip 1 in the electrolytic solution 3 ″. The etching resist surface of the metal strip 1 is passed downward, and the metal strip 1 is etched. Opposite to the resist surface side, the cathode 5 ″ is directed upward, and the distance between the etching resist surface and the cathode is set at a predetermined interval, and the conductor rolls 13 ″ and 14 ″ are disposed on the metal strip 1. On a surface quenching resist is not applied, are arranged so as backup roll 19 and 20 are respectively abut the etching resist surface of the metal strip 1. Conductor rolls 13 ″, 14 ″ (anode) and cathode 5 ″ are connected to a DC power supply 36 and subjected to electrolytic etching by direct energization to the metal strip 1. The conductor rolls 13 ″, 14 ″ It is disposed outside the electrolytic solution 3 ″ in the electrolytic etching tank 2 ″ to prevent occurrence of a short circuit current.
Japanese Unexamined Patent Publication No. 63-042332 Japanese Patent Publication No. 08-006140 Japanese Patent Laid-Open No. 10-204699

  A method in which an etching mask is formed by applying an etching pattern to one surface as in the above prior art, and the remaining surface on one side is continuously grooved by electrolytic etching on a metal strip that is a conductor. An iron mask is formed by applying an etching pattern to the surface of one side of the wire, and continuously grooving by electrolytic etching. Various production methods have been proposed for producing grain-oriented silicon steel sheets, but all are applied with the conductor roll (metal strip) side as the anode and the electrode side as the cathode.

While working on improving the characteristics of a low iron loss unidirectional silicon steel sheet in which iron loss does not deteriorate after strain relief annealing used for a transformer core or the like by such conventional direct-current electrolytic etching, The inventors have found that the variation in the geometric shape of the cross section of the etching groove causes the variation in magnetism (iron loss), which is an obstacle to stably producing a product having good magnetism. It was also found that the problem of the stability of the groove shape of the etched portion, which became a new problem here, is caused by stagnation of the electrolytic solution (electrolytic precipitate) due to the anodic reaction in the etched portion. As a result of further studies, this stagnation of the electrolyte solution can be eliminated by periodically generating H ₂ gas due to the cathodic reaction for a very short period of time. As a result, the groove width and depth of the etched portion are reduced. Knowing that it can be made more uniform, the invention relating to the direct energization type continuous electrolytic etching method and the direct energization type continuous electrolytic etching apparatus of the metal strip is completed, and the invention is first described in Japanese Patent Application No. 2003-207619. Applied for a patent.

However, the invention disclosed in the above Japanese Patent Application No. 2003-207619 is based on the premise of electrolytic etching when the amount of metal dissolved in the electrolytic solution is relatively small, and the electrolytic etching is continued for a long time. Thus, the problem of electrolytic etching in a state in which the amount of dissolved metal in the electrolytic solution is increased and the solution thereof have not been disclosed.
The present invention advantageously solves the above-described problems, and can perform a stable electrolytic etching including a state in which a metal strip is continuously subjected to electrolytic etching for a long time. It is an object of the present invention to provide a method and a direct energization type continuous electrolytic etching apparatus.

First, a preliminary study up to the present invention will be described.
That is, in order to collect basic data on direct energization type continuous electrolytic etching of a metal band, an etching mask is formed by applying an etching pattern to one surface similar to the invention described in Patent Document 3, A preliminary experiment was carried out in which a groove was continuously formed by electrolytic etching in a metal strip having a conductive surface on the other side.

  FIG. 5 shows an outline of the experimental apparatus in a longitudinal sectional view in the longitudinal direction. The main structure is that conductor rolls 13 ″ and 14 ″ are in contact with the surface which is a conductor on the other side of the metal band 1 on which the etching mask is formed by applying an etching pattern to the surface on one side which is continuously passed through. The electrolytic solution 3 ″ is filled between the electrodes 5 ″ arranged opposite to the metal strip 1 in the electrolytic cell 2 ″, and the conductors 13 ″, 14 ″ and the electrodes 5 ″ are provided with conductors. The DC power supply 36 is arranged with the roll side as the anode and the electrode side as the cathode. A switch 46 is installed between the DC power supply 36 and the conductor rolls 13 ″ and 14 ″, and a resistor 26 is installed between the DC power supply 36 and the electrode 5 ″. The switch 46 is closed. Thus, a negative voltage is applied to the electrode side between the conductor rolls 13 ″ and 14 ″ and the electrode 5 ″. Further, the voltage application is interrupted by opening the switch 46. Further, by increasing / decreasing the resistance 26, the negative voltage applied to the electrode 5 ″ between the conductor rolls 13 ″, 14 ″ and the electrode 5 ″ is increased / decreased. Note that backup rolls 19 and 20 are disposed on the etching resist surface side of the metal band 1 where the conductor rolls 13 ″ and 14 ″ contact the metal band 1. In addition, a ringer roll (not shown) is installed on the entrance / exit side of the electrolytic cell 2 ″ as a transport roll for the metal strip 1 to suppress the outflow of the electrolytic solution 3 ″ to the outside of the cell. The sink rolls 11 and 12 are installed to keep the distance between the electrode 5 ″ and the metal strip 1 constant.

FIG. 6 shows an example of voltage application to the electrode 5 ″ between the conductor rolls 13 ″ and 14 ″ and the electrode 5 ″ in the preliminary experiment. It is adjusted so that a constant electrolytic current flows between the metal strip 1 and the electrode 5 ″. The electrode 5 ″ is a so-called cathode, and an electrode made of SUS316 is adopted.
In such a state, current flows from the conductor rolls 13 ″, 14 ″ to the metal strip 1, and further flows through the electrolyte 3 ″ to the electrode 5 ″.

Using the apparatus shown in FIG. 5 as described above, the present inventors pass the metal strip 1 at a constant traveling speed and apply the voltage shown in FIG. 6 between the conductor roll and the electrode. Then, a groove was formed by electrolytic etching of a metal strip provided with an etching pattern by providing an etching pattern, and the groove shape (geometric shape, groove width, groove depth) was observed.
The metal band 1 used in the experiment has no forsterite (Mg ₂ SiO ₄ ) coating on the surface, finish annealed, and directional silicon with an etching pattern formed on one surface thereof by forming an etching mask. It is a steel plate. The electrolytic solution 3 ″ is an aqueous solution of NaCl.

  FIG. 4 shows observation results (b) to (d) of the groove shape (A) formed by the electrolytic etching targeted by the present invention and the groove shape formed by the electrolytic etching of this experiment. The groove shape of the electrolytic etching observed here is very unstable in geometric shape so that it can be classified as (b) inclined type, (c) widening type, and (d) local etching type. It turned out that the width and the depth of the groove are also easily fluctuated.

In response to such a problem, the present inventors changed the steel type of the metal strip or changed the electrolysis conditions (NaCl concentration, electrolyte temperature, effective current density of the groove), and changed the groove conditions under various conditions. Although the shape was investigated, it was not possible to stabilize the shape of the groove and greatly reduce the variation in the depth and width of the groove. Furthermore, the inventors of the present invention have found that the instability of the etch groove shape is mainly caused by stagnation (electrolytic precipitate) of the electrolytic solution due to the anodic reaction in the etching portion. Therefore, as a result of further examination on the elimination of the stagnation of the electrolytic solution, it is possible to eliminate the stagnation of the electrolytic solution in the etching portion by periodically generating H ₂ gas due to the cathodic reaction for a very short period of time. It has been found that the groove width and groove depth can be made more uniform.
However, the above knowledge is based on the premise of electrolytic etching when the amount of metal dissolved in the electrolytic solution is relatively small. Since it is customary to perform etching, an increase in the amount of dissolved metal in the electrolytic solution is inevitable. In such a case, it was assumed that a new problem of adhesion of the metal in the electrolytic solution to the metal band (dirt of the metal band) also becomes obvious.

  Therefore, the present inventors have carried out electrolytic etching of a metal strip continuously for a long time, and even when the amount of dissolution of the metal in the electrolytic solution is increased, the shape of the groove formed by electrolytic etching is stabilized, and the metal We have made further studies on electrolytic etching that can achieve both the beautification of the surface of the belt (the absence of dirt). As a result, by arranging a plurality of electrodes in the electrolytic cell and fixing the last electrode to the anode (cathode), the metal in the electrolytic solution does not adhere to the surface of the metal strip, and the shape of the electrolytic etching groove shape It has been found that the occurrence of variations can be advantageously avoided.

The present invention has been completed only after further studies based on the above new findings. The gist of the present invention is as follows.
(1) An etching mask is formed by applying an etching pattern to the surface on one side, and the metal band whose surface on the other side is a conductor is continuously grooved by direct energization electrolytic etching. A continuous electrolytic etching method,
One set or two or more sets of electrode (B-type electrode) disposed opposite to the etching surface of the metal band and a pair of conductor rolls (A-type conductor roll), and the progression of the metal band The A ′ conductor roll and the B ′ electrode are disposed one after the other in sequence, and a pair of A ′ conductor rolls and B ′ electrodes are disposed, and an electrolyte is filled between the metal strip and the electrodes. The roll is brought into contact with the other surface where the metal mask etching mask is not formed,
Between the A system conductor roll and the B system electrode,
(I) voltage application using the B-system electrode as an anode during a time M = 3 to 10 msec;
(II) During the time N = 4M to 20Mmsec, the voltage application using the B-system electrode as a cathode is alternately repeated, and at the time of the transition from the voltage application (I) to the voltage application (II). During the time αmsec (α> 0) and during the time βmsec (β> 0) during the transition from the voltage application (II) to the voltage application (I), the A-system conductor roll and the B-system Insert a time interval in which no voltage is applied between the electrodes,
A direct energization type continuous electrolytic etching method for a metal strip, wherein a voltage is applied between the A 'conductor roll and the B' electrode so that the B 'electrode serves as a cathode.
(2) An etching mask is formed by applying an etching pattern to the surface on one side, and the metal band whose surface on the other side is a conductor is continuously grooved by direct energization electrolytic etching. Type continuous electrolytic etching apparatus,
(A) an electrolytic etching tank;
(B) One or two or more sets of electrodes (B-type electrodes) that are immersed in the electrolytic solution of the electrolytic etching tank and are opposed to the etching surface of the metal strip, and pair with the electrodes A conductor roll (system A conductor roll);
(C) a set of A ′ conductor roll and B ′ electrode, which is immersed in the electrolytic solution of the electrolytic etching tank and is disposed after the last of the A system conductor roll and the B system electrode;
(D) a sink roll for immersing the metal strip in the electrolytic solution of the electrolytic etching tank;
(E) Between the A-system conductor roll and the B-system electrode, (I) voltage control in which the B-system electrode becomes an anode for a predetermined M time, and (II) a predetermined N (N> M) time, B Voltage control in which the system electrode becomes a cathode, and (III) the A system conductor roll and the B of time αmsec (α> 0) between the voltage application of (I) and the voltage application of (II) No voltage is applied between the system electrodes; and (IV) the A system conductor roll of time βmsec (β> 0) between the voltage application of (II) and the voltage application of (I); A power supply device that performs voltage control arbitrarily combining not applying a voltage between the B-system electrodes;
(F) A direct energization type continuous electrolytic etching apparatus for a metal strip, characterized by having a power supply device for voltage control between the A ′ conductor roll and the B ′ electrode, with the B ′ electrode serving as a cathode.

  According to the present invention, in contrast to the problem of variation in groove shape due to electrolytic etching that could not be achieved by conventional direct-current electrolytic etching, including the case where a metal strip is subjected to continuous electrolytic etching for a long time. It is possible to advantageously solve, to stabilize the shape of the groove formed by electrolytic etching, to make the groove width and groove depth more uniform, and to obtain a metal band with a beautiful surface (without dirt). . Particularly suitable for the production of low iron loss unidirectional electrical steel sheet with low iron loss that is difficult to deteriorate after stress relief annealing used for iron cores of power transformers, etc. Since the electrolytic etching apparatus can be provided, the effect is great.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of an equipment according to the present invention, in which an etching mask is formed on one surface and an etching mask is formed, and the remaining surface on one side is continuously grooved by electrolytic etching on a metal band that is a conductor. Is schematically shown in a longitudinal vertical sectional view.
The main structure is that the A-system conductor rolls 13 and 14, A ′ conductor rolls 13 ′ and 14 ′ that are in contact with the surface of the remaining conductor on one side of the metal band 1 having the etching mask formed on one side, the metal band 1, Between the B system electrode 5 and the B ′ electrode 5 ′ disposed opposite to each other through the electrolytic solutions 3 and 3 ′ in the electrolytic cells 2 and 2 ′, and between the A system conductor rolls 13 and 14 and the B system electrode 5. The DC power supply devices 31 and 32, and the DC power supply device 33 are disposed between the A 'conductor rolls 13' and 14 'and the B' electrode 5 '. Switches 41 and 42 are respectively installed between the DC power supply devices 31 and 32 and the A-system conductor rolls 13 and 14, and between the DC power supply devices 31 and 32 and the B-system electrode 5, Resistors 21 and 22 and switches 41 'and 42' are installed, respectively. By closing the switches 41, 41 'and opening the switches 42, 42', a negative voltage is applied to the B system electrode 5 between the A system conductor rolls 13, 14 and the B system electrode 5, Further, a positive voltage is applied to the B system electrode 5 between the A system conductor rolls 13 and 14 and the B system electrode 5 by opening the switches 41 and 41 ′ and closing the switches 42 and 42 ′. To do. Note that voltage application is interrupted by opening all the switches 41, 41'42, 42 '. Further, by increasing / decreasing the resistors 21, 22, the negative positive voltage applied to the B system electrode 5 between the A system conductor rolls 13, 14 and the B system electrode 5 is increased / decreased. Here, it is assumed that when the electric resistance of the electric circuit of electrolytic etching does not change, the control of the energization amount per unit time can be replaced by voltage control.

  A switch 43 is installed between the DC power supply 33 and the A 'conductor rolls 13' and 14 ', and a resistor 23 is installed between the DC power supply 33 and the B' electrode 5 '. ing. By closing the switch 43, a negative voltage is applied to the B 'electrode 5' between the A 'conductor rolls 13', 14 'and the B' electrode 5 '. Note that the voltage application is interrupted by opening the switch 43. Further, by increasing / decreasing the resistance 23, the negative voltage applied to the B 'electrode 5' between the A 'conductor rolls 13', 14 'and the B' electrode 5 'is increased / decreased. Here again, it is assumed that when the electric resistance of the electric circuit of electrolytic etching does not change, the control of the energization amount per unit time can be replaced by voltage control.

  Note that the backup rolls 15, 16, 17, and 18 are provided on the etching resist surface side of the metal strip 1 where the A-system conductor rolls 14 and 15 and the A ′ conductor rolls 14 ′ and 15 ′ are in contact with the metal strip 1. Is arranged. In addition, as a transport roll for the metal strip 1, a ringer roll (not shown) is installed on the entry / exit side of the electrolytic cells 2, 2 'to suppress the outflow of the electrolytes 3, 3' to the outside of the bath, Sink rolls 7, 8, 9, and 10 are installed in the tank, and the distance between the B system electrode 5, the B ′ electrode 5 ′, and the metal strip 1 is kept constant.

FIG. 2A shows an example of voltage application to the B system electrode 5 between the A system conductor rolls 13 and 14 and the B system electrode 5 according to the present invention, and FIG. An example of voltage application to the B ′ electrode 5 ′ between the ′, 14 ′ and the B ′ electrode 5 ′ is shown.
First, as shown in FIG. 2 (a), in the present invention, a negative voltage is applied to the B-system electrode 5 between the B-system electrode 5 and the A-system conductor rolls 13 and 14, that is, to the metal band 1. By performing each positive voltage application, a predetermined electrolytic current is adjusted to flow. For example, when the voltage applied to the B-system electrode 5 is a negative voltage application (becomes a cathode), a predetermined electrolytic current is applied to the surface where the conductivity of the metal strip 1 is maintained by the A-system conductor rolls 13 and 14. Then, it flows to the metal band 1, and further flows to the B-type electrode 5 through the etching pattern portion (to become an anode) of the metal band 1 facing the B-type electrode 5 and the electrolytic solution 3. This electrolytic current causes an anodic reaction Me → Me ⁺ + e ⁻ (when the metal band is a steel band, Fe → Fe ²⁺ + 2e ⁻ ) in the etching pattern portion of the metal band 1 on the side facing the B-based electrode 5.
As a result, electrolytic etching proceeds. Conversely, when the voltage applied to the B-system electrode 5 is a positive voltage application (becomes an anode), a predetermined current flows in the opposite direction to the above case, but the B-system electrode 5 (anode) In the etching pattern portion of the metal band 1 on the side opposite to (becomes)) (to become the cathode), the cathode reaction (electron acceptance reaction)
2H ⁺ + 2e ⁻ → H ₂ ↑
The stagnation (dissolved precipitate) of the electrolytic solution in the vicinity of the etching pattern portion generated during the electrolytic etching can be reduced by the H ₂ gas generated by the above.
In the present invention, since the B-based electrode 5 may be an anode or a cathode, it may be made of an insoluble material such as a Pt-based material so that the electrode itself is not subjected to electrolytic etching in the case of the anode. It is good to make.

Further, in the present invention, between the A-system conductor rolls 13 and 14 and the B-system electrode 5, (I) the conduct roll side for a time M = 3 to 10 msec is set as a cathode, and the electrode side is set as an anode. It is necessary to alternately repeat voltage application and (II) voltage application between time N = 4 M to 20 Mmsec with the conduct roll side as the anode and the electrode side as the cathode.
When the conductor roll of (I) is a cathode and the electrode is an anode, when M is a voltage application time (msec), H _{2 on} the surface of the groove formed by etching is applied when the voltage is applied for a time of less than 3 msec. This is because the generation of gas is not sufficient to remove the stagnation of the electrolytic solution (precipitate) in the groove, and on the other hand, when the voltage is applied for a time in which M exceeds 10 msec, the current efficiency of electrolytic etching is reduced. .
Further, when the conductor roll of (II) is an anode and the electrode is a cathode, when N is a voltage application time (msec), a voltage application of less than 4 Mmsec causes a decrease in the current efficiency of electrolytic etching, This is because, when a voltage exceeding 20 Mmsec is applied, the stagnation (precipitate) in the groove formed by electrolytic etching becomes too large, and it becomes difficult to remove the stagnation of the electrolyte (precipitate) in the groove. .

Also, during the transition from the voltage application of (I) to the voltage application of (II) for a time αmsec (α> 0), and from the voltage application of (II) to the voltage application of (I). In order to perform electrolytic etching stably, it is also effective to insert a time interval during which no voltage is applied between the conductor roll and the electrode for a time βmsec (β> 0). In an actual electrolytic etching facility, an electrical so-called LC circuit is formed between the electrolytic power supply device and the conductor roll, between the electrolytic power supply device and the electrode, or between the electrode and the metal strip, and the applied voltage. This is because the time delay that occurs when switching between the anode and the cathode may become a problem. The problem of time delay due to the LC circuit becomes more apparent as the equipment scale increases.
However, it is not preferable to use a time during which no voltage is applied so that α or β exceeds 10 msec, because it causes a decrease in the electrolytic etching rate or an increase in the length of the electrolytic etching equipment (electrolyzer). Also, α or β is 1 msec. If it is less than 1, it cannot be an effective solution to the problem of time delay caused by the LC circuit, so α or β is preferably in the range of 1 to 10 msec.

In addition, it is also possible to reduce the amount of energization per unit time (current density) when applying the voltage of (I) below the amount of energization per unit time when applying the voltage of (II). This is an embodiment that is effective and desirable to be performed in an automated manner. When the energization amount per unit time when the voltage (I) is applied exceeds the energization amount per unit time when the voltage (II) is applied, the electrolytic etching rate decreases or the electrolytic etching equipment (electrolysis This is because the length of the tank is undesirably increased.
On the other hand, setting the amount of energization per unit time when applying the voltage (I) to 10 A / dm ² or more is also effective for performing electrolytic etching stably. If it is less than 10 A / dm ² , the jet power of the generated H ₂ gas is small, and the efficiency of removing the stagnation in the groove formed by electrolytic etching deteriorates, which is not preferable.
In addition, it is also effective to install a plurality of electrolytic cells in which A-based conductor rolls and B-based electrodes are disposed as means for performing electrolytic etching treatment on the metal strip at high speed.

Next, as shown in FIG. 2 (b), in the present invention, the B 'electrode 5' is placed between the A 'conductor rolls 13', 14 'and the B' electrode 5 'installed in the latter half of the electrolytic cell. By applying a negative voltage to the metal band 1, a predetermined electrolytic current flows from the A 'conductor rolls 13' and 14 'to the metal band 1, and further, the etching pattern portion of the metal band 1 facing the B' electrode 5 '. It flows to the B 'electrode 5' (becomes a cathode) through the electrolytic solution 3 '(becomes the anode). This electrolytic current causes an anodic reaction Me → Me ⁺ + e ⁻ (when the metal band is a steel band, Fe → Fe ²⁺ + 2e ⁻ ) in the etching pattern portion of the metal band 1 on the side facing the B ′ electrode 5 ′.
As a result, electrolytic etching proceeds. Therefore, the cathode reaction Me ⁺ + e ⁻ → Me on the surface of the metal strip opposite to the B ′ electrode 5 ′, which is the last electrode, by applying a voltage to the electrode of the electrolytic cell in the latter half portion.
Therefore, it is possible to prevent adhesion (dirt) of the metal in the electrolytic solution to the surface of the metal band due to this cathodic reaction, and to obtain a metal band with a beautiful surface appearance.

The negative voltage applied to the B 'electrode 5' between the A 'conductor rolls 13' and 14 'and the B' electrode 5 'here is applied to the B-system electrode in the first half of the electrolytic cell. The negative voltage application amount is preferably equal to or less than the negative voltage application amount, and is preferably equal to or higher than the voltage application amount at which the current density is 10 A / dm ² . The amount of negative voltage applied to the B-system electrode in the first half of the electrolytic cell is usually the maximum amount of allowable voltage that does not impede the etching width to minimize the length of the electrolytic cell. However, this applied amount cannot be exceeded even in the latter half of the electrolytic cell. On the other hand, the lower limit of the voltage application amount here may be a minimum voltage application that can prevent the adhesion of dirt on the surface of the metal band, but the effect is not achieved when the voltage application amount is less than 10 A / dm ^2. It is because it cannot be obtained.
Further, the B ′ electrode 5 ′ is a so-called cathode (cathode), and an insoluble electrode is not necessarily employed. For example, an electrode made of SUS316 or the like may be employed.

In the latter half of the electrode arrangement, a multi-pole arrangement is usually not necessary. Further, the B-system electrode and the B ′ electrode are not limited to being disposed in separate electrolytic cells, and may be disposed in the same electrolytic cell.
In the present invention, the electrode arrangement of the electrolytic cell in the latter half is not limited to the B ′ electrode as shown in FIG. 3 and may be a B-type electrode. In this case, the present invention can be implemented if the voltage applied to the B-system electrode is, for example, the voltage applied to the B ′ electrode as shown in FIG. By setting it as such an equipment structure, it can be set as the equipment which gave not only implementation of this invention but versatility.

  The electrolytic power supply device used in the present invention is not limited to the switching system using the DC power supply device and the switch described above, and any system can be used as long as it can take the voltage application cycle described above. The so-called 6-phase half-wave rectified waveform is effective in both the transistor system and the inverter system. Also, it is not always necessary to install a single resistor, and any method can be used as long as it can control the energization amount when the voltage is applied. Of course, the resistor may be combined with a DC power supply method.

  According to the present invention, the system shown in FIG. 1 has a B-system electrode between the A-system conductor roll and the B-system electrode, and a B 'electrode between the A' conductor roll and the B 'electrode, respectively. Even when groove processing by direct energization type continuous electrolytic etching for applying voltage shown in (a) and (b) is performed continuously for a long time, the shape of the groove formed by electrolytic etching (geometric shape, groove The width and the depth of the groove are very stable, and all have a concave shape as shown in FIG. 4A, the width of the groove and the depth of the groove become more uniform, and the variation is greatly improved. Also, the metal strip is not dirty and the surface appearance is beautiful.

The present invention applies to all cases where an etching mask is formed by applying an etching pattern to the surface on one side, and the remaining surface on one side continues to a metal band as a conductor and is stably grooved by electrolytic etching. It is effective. In particular, the effect is particularly effective for strain-resistant annealed low iron loss unidirectional silicon steel sheets that have been subjected to electrolytic etching on a finish-annealed silicon steel sheet with an etching mask formed on the surface and no iron loss deterioration due to strain relief annealing. Is big. This is because the variation in the groove shape formed by electrolytic etching becomes magnetic variation, and the problem becomes particularly noticeable.
Of course, the effect is effective even in a directional silicon steel sheet in which an etching mask is formed by applying an etching pattern to the surface of the cold rolled sheet.

Hereinafter, the present invention will be specifically described based on examples.
The metal strip before electrolytic etching is cold-rolled to the final sheet thickness under the following conditions, decarburized and annealed, and then an annealed separator made of MgO is applied to the surfaces on both sides and dried, and further annealed. The forsterite (Mg ₂ SiO ₄ ) film formed on both surfaces during finish annealing is removed, and a tension-imparting film (phosphoric acid-based insulating film) is applied to the surface on one side, and then baked. The grain-oriented silicon steel sheet is formed with an etching pattern in which the surface of one side on which the tension-imparting film is baked is selectively removed by a laser beam to expose the ground iron. In addition, since this tension | tensile_strength type | mold film | membrane is an electrically insulating film, it decided to utilize as an etching mask.

The grain-oriented silicon steel sheet that had been subjected to the pretreatment as described above was subjected to an electrolytic etching treatment using the direct current continuous electrolytic etching apparatus shown in FIG. 1 or FIG.
[Directional silicon steel sheet] Thickness 0.22 mm, width 1000 mm
[Etching mask] 5 mm pitch in the direction perpendicular to the plate longitudinal direction (plate width direction),
It has an etching pattern with a width of 0.20 mm.
[Electrolyte] Composition 500 g-NaCl / 1, liquid temperature 50 ° C.
[Target groove depth] 0.02mm
[Electrolytic current] 200 C / dm ²
[Iron content of electrolyte at start of electrolysis] 0 g / l, 0.2 g / l
After the electrolytic etching, the variation in the shape pattern of the groove and the depth of the groove formed by the electrolytic etching in the steel plate width direction was evaluated.
Table 1 shows test conditions and results when the voltage shown in FIG. 2 or 6 is applied to the apparatus shown in FIG. 1 or FIG.

No. In the examples of the present invention shown in 1 to 5, the groove shapes are all concave (A) and stable, and as a result, the groove depth variation (%) ((standard deviation of groove depth) / ( It can be seen that the average value of the groove depth) × 100) is very small. Furthermore, it can be seen that the surface of the steel strip is clean and beautiful.
On the other hand, No. of the comparative example in which the negative voltage application time to the conductor roll is short. No. 1 and Comparative Example No. 1 in which the ratio of positive voltage application time / negative voltage application time exceeds 20. In Nos. 2 and 3, the shape of the groove is partially concave (A), but the shape of the groove is still an inclined type (B), widening type (C), and local etching type (D). As a result, the variation in depth was large and the quality was not satisfactory.

In addition, a comparative example No. similar to the voltage application method (FIG. 6) for the conventional metal strip. In No. 4, the concave shape (b) is hardly recognized, and the inclined type (b), the widening type (c), and the local etching type (d) are mostly formed. The variation was large.
Further, in the comparative example No. in which no negative voltage is applied to the B ′ electrode between the A ′ conductor roll and the B ′ electrode. In Nos. 5 to 9, the groove shape was all concave (A) and stable, and as a result, the variation in groove depth (%) was very small, but a small amount of dirt was observed on the surface of the steel sheet. .
In addition, comparative example No. with a new electrolyte solution. In No. 10, the other conditions were the same as in Comparative Example 6, but no contamination of the surface of the steel sheet was observed.

It is a schematic explanatory drawing by the longitudinal direction vertical cross-sectional view of the installation which continuously carries out a groove process by the direct electrolysis type electrolytic etching to the metal strip in which the etching mask which provided the etching pattern on the surface based on this invention was formed. The figure which shows the voltage application to B system electrode between A system conductor roll and B system electrode based on this invention, and the voltage application to B 'electrode between A' conductor roll and B 'electrode It is. Schematic explanation according to the vertical cross-sectional view in the longitudinal direction of another apparatus according to the present invention for continuously grooving a metal band having an etching mask provided with an etching pattern on at least one surface by direct electrolysis electrolytic etching FIG. It is a figure which classify | categorizes and shows the pattern of the cross-sectional shape of the groove | channel formed by electrolytic etching. It is similar to a conventional metal strip direct energization type continuous electrolytic etching apparatus according to the prior art, and is an apparatus used in a preliminary experiment leading to the present invention, in which a metal band having an etching mask provided with an etching pattern on one surface is formed. It is a schematic explanatory drawing by the longitudinal direction vertical sectional view of the equipment which carries out continuous groove processing by direct energization type electrolytic etching. It is a figure which shows the example of a voltage application to the electrode between the conductor roll and electrode used in the preliminary experiment by the apparatus of FIG. 5 which concerns on a prior art. 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 cross-sectional view.

Explanation of symbols

1 Metal strip 2, 2 ', 2 "Electrolysis (etching) tank 3, 3', 3" Electrolyte 5 B-system electrode 5 'B' electrode 5 "Cathode
7, 8, 9, 10, 11, 12 Sink roll (dipping roll)
13, 14 A system conductor roll 13 ', 14' A 'conductor roll 13 ", 14" conductor roll 15, 16, 17, 18, 19, 20 Backup roll 21, 22, 23, 24, 25, 26 Resistance 31, 32, 33, 34, 35, 36 DC power supply device 41, 41 ', 42, 42', 43 Switch 44, 44 ', 45, 45', 46 Switch

Claims (2)

An etching mask is formed by applying an etching pattern to the surface on one side, and the metal strip with the remaining surface on the other side is continuously grooved by direct energization electrolytic etching, directly energizing continuous electrolysis of the metal strip. An etching method comprising:
One set or two or more sets of electrode (B-type electrode) disposed opposite to the etching surface of the metal band and a pair of conductor rolls (A-type conductor roll), and the progression of the metal band The A ′ conductor roll and the B ′ electrode are disposed one after the other in sequence, and a pair of A ′ conductor rolls and B ′ electrodes are disposed, and an electrolyte is filled between the metal strip and the electrodes. The roll is brought into contact with the other surface where the metal mask etching mask is not formed,
Between the A system conductor roll and the B system electrode,
(I) voltage application using the B-system electrode as an anode during a time M = 3 to 10 msec;
(II) During the time N = 4M to 20Mmsec, the voltage application using the B-system electrode as a cathode is alternately repeated, and at the time of the transition from the voltage application (I) to the voltage application (II). During the time αmsec (α> 0) and during the time βmsec (β> 0) during the transition from the voltage application (II) to the voltage application (I), the A-system conductor roll and the B-system Insert a period of time when no voltage is applied between the electrodes,
A direct energization type continuous electrolytic etching method for a metal strip, wherein a voltage is applied between the A 'conductor roll and the B' electrode so that the B 'electrode serves as a cathode. An etching mask is formed by applying an etching pattern to the surface on one side, and the metal strip with the remaining surface on the other side is continuously grooved by direct energization electrolytic etching, directly energizing continuous electrolysis of the metal strip. An etching apparatus,
(A) an electrolytic etching tank;
(B) One or two or more sets of electrodes (B-type electrodes) that are immersed in the electrolytic solution of the electrolytic etching tank and are opposed to the etching surface of the metal strip, and pair with the electrodes A conductor roll (system A conductor roll);
(C) a set of A ′ conductor roll and B ′ electrode, which is immersed in the electrolytic solution of the electrolytic etching tank and is disposed after the last of the A system conductor roll and the B system electrode;
(D) a sink roll for immersing the metal strip in the electrolytic solution of the electrolytic etching tank;
(E) Between the A-system conductor roll and the B-system electrode, (I) voltage control in which the B-system electrode becomes an anode for a predetermined M time, and (II) a predetermined N (N> M) time, B Voltage control in which the system electrode becomes a cathode, and (III) the A system conductor roll and the B of time αmsec (α> 0) between the voltage application of (I) and the voltage application of (II) No voltage is applied between the system electrodes; and (IV) the A system conductor roll of time β msec (β> 0) between the voltage application of (II) and the voltage application of (I), A power supply device that performs voltage control arbitrarily combining not applying a voltage between the B-system electrodes;
(F) A direct energization type continuous electrolytic etching apparatus for a metal strip, comprising a power supply device for performing voltage control between the A ′ conductor roll and the B ′ electrode so that the B ′ electrode serves as a cathode.

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