JPH06264290A - Continuous electroplating method of metallic strip to form double layers - Google Patents

Abstract

PURPOSE:To simultaneously apply plural layers of electroplating on both surfaces of a strip in one line, to nearly completely correct the center misalignment and shape defect of the strip and to obviate the generation of flaws, etc., due to contact of the strip with electrode pads. CONSTITUTION:The electrode pads 1 are divided to a plurality in the progressing direction of the strip and are so disposed that the electrolyte does not infiltrate the adjacent sections at the divided points, at the time of executing electroplating by bending the metallic strip traveling line to an arc shape, arranging the electrode pads 1 facing each other on both sides of the strip 3 along this arc-shaped part and fluidizing the electrolyte between the electrode pads 1 and the strip. The desired plating liquid is then blown between the strip 3 and the pads 1 by each of the divided electrode pads, by which the plural plating layers are formed on the strip surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous electroplating method for a metal strip such as a steel plate, and more particularly to a multi-layer continuous electroplating method capable of continuously plating a plurality of layers in the strip thickness direction. .

[0002]

2. Description of the Related Art In the electroplating method, the electrode current is increased by increasing the electrolytic current density to meet the needs of increasing the basis weight and increasing the plate passing speed. It is common practice to reduce the voltage loss due to the electrolytic solution by reducing the distance between the strip and the strip as much as possible. Then, some proposals have been made as means for simultaneously fulfilling these needs.

For example, the means disclosed in Japanese Patent Publication No. 58-32239 and Japanese Patent Publication No. 61-21319 have a vertical or horizontal plating apparatus in which electrode pads for injecting an electrolytic solution are arranged so as to sandwich a strip. By injecting the electrolytic solution onto the strip surface and forcibly circulating the plating solution,
By promoting the supply of plating metal ions to increase the electrolytic current density, and by generating static pressure on both sides of the strip surface by the ejected electrolytic solution, the strip is held at the center between the electrode pads, and the strip C Shape defects such as warpage are corrected, and as a result, the gap between the electrode and the strip is reduced to reduce voltage loss.

However, in such a conventional device, the distance between the electrode and the strip is limited to 10 mm at most. Because, in principle, a static pressure difference occurs only when there is a difference in the distance between the strip and the electrode pad that sandwiches it, which corrects the strip position and shape.
This is because the center deviation of the strip and the defective shape are improved from the initial state, but they are not completely eliminated, and the strain stress of the strip and the correction force due to the static pressure remain balanced. Even if the center of the strip is slightly misaligned or the shape is poor, if the current density is high and the distance between the electrode and the strip is small, the distribution of the plating amount in the width direction of the strip is not uniform and the flaws may occur due to the contact between the strip and the electrode pad. Invite.

Further, in the conventional electroplating means, no technique has been found in which a plurality of layers of electroplating are simultaneously formed on both surfaces of the strip on the same strip line.

[0006]

DISCLOSURE OF THE INVENTION The present invention corrects the above-described center deviation of the strip and the defective shape almost completely, and even when the distance between the electrode and the strip is small, the amount of plating deposition is non-uniform or the strip is stripped. It is an object of the present invention to provide an electroplating method which does not cause flaws or the like due to contact between the strip and the electrode pad, and which is capable of simultaneously performing electroplating of a plurality of layers on both surfaces of the strip.

[0007]

The gist of the present invention is as follows. (1) When the metal strip running line is bent in an arc shape, the electrode pads facing each other are sandwiched along the arc shape part, and the electrolytic solution is caused to flow between the electrode pad and the strip to perform electroplating. , The electrode pad is divided into a plurality of parts in the strip advancing direction so that the electrolytic solution does not infiltrate into adjacent sections at the divided parts, and the plating solution is independently blown into the strip between the strips for each divided electrode pad. A multi-layer continuous electroplating method for a metal strip, which comprises forming a plurality of plating layers on the surface. (2) The electroplating method according to the above (1), in which an electrolytic solution is sprayed from each end of each divided electrode pad to generate a static pressure between the pad and the strip, and the strip is held stably.

[0008]

In the present invention, the electrode pad is of non-contact type, so-called bend floater type.
Static pressure is created between the strip and the pad to hold the strip along the required line. Moreover, since the running line of the strip is bent in the running direction to form the arc portion, the rigidity is increased in the width direction of the strip, and the defective shape is corrected. Further, since the electrode pads are divided so as to be almost completely independent of each other, and different or the same kind of electrolytic solution is blown so that the electrolytic solution is mutually blocked, a good multi-layer electroplating layer is formed. It can be formed on both sides of the strip.

The present invention will be described below with reference to the drawings. FIG. 1 shows the principle of the present invention and an example of equipment. As shown in the figure, the electroplating apparatus for carrying out the present invention is such that the strip traveling line is forced to bend downward in the traveling direction at the plating position between the two energizing rolls 6 of the strip 3 traveling in the horizontal direction. And the electrolytic plating is performed at this curve (arc). That is, a bend floater type insoluble electrode pad 1 is arranged to face each other with a curved strip 3 interposed therebetween, and the electrode pad 1 is divided into two sections A and B along the strip advancing direction as shown in the drawing. I am configuring. Of the divided electrode pads, the strip output side is the first plating pad 1A and the input side is the second plating pad 1B.

In the first electrode pad 1A, however, the jet nozzles 2a to 2d for injecting the electrolytic solution are provided near both ends of the first electrode pad 1A.
However, the jet nozzles 2e ...
2 h is provided, and a static pressure is generated between the pad and the strip surface by blowing a required type of plating solution from each nozzle, and at the same time, electroplating according to the type of plating solution is performed. In addition, the nozzles 2a and 2e located on the strip exit side among the nozzles inside the first pad 1A and the second pad 1B are arranged so that the flow of the electrolytic solution is opposite to the traveling direction of the strip, that is, countercurrent. The flow velocity of the plating solution is maintained at a high value compared to other nozzles, achieving electroplating at high current density and static pressure generation between pads and strips.

Further, an electrolyte discharge pipe 4 is provided between the electrode pads 1A and 1B divided into two sections, and a plating liquid for the first plating section is provided behind the discharge pipe 4. Sealing means are provided to prevent entry into the next second plating section. As the sealing means, as shown in FIG. 1 (b), a sealing roll 5 which directly clamps the strip 3 and rotates is suitable, but other sealing means may be used.

In the figure, 6 is a conducting conductor roll installed at the start and end of the curved running portion of the strip, and 7 is connected to the inlet and outlet sides of the electrolysis section formed by both electrode pads. This is an electrolytic solution tank, and the electrolytic solution discharge hole 8 is provided in the tank. Reference numeral 9 is a draining roll provided on the ceiling of the electrolytic solution tank 7.

In the present invention, the arc portion is always provided in order to bend the running direction of the strip.
An example of the installation angle range of the electrode pads on both sides of the arc portion is 180 ° as shown in FIG. 1, but the present invention is not limited to this, and a curvature from a minimum of about 90 ° to a maximum of about 250 ° is possible. It is also possible to add. Further, the number of divided sections is not limited to 2, and may be 3 or more, and the number of plating layers increases according to the number of sections.

[0014]

【Example】

(Electrode pad specifications) Pad diameter 500mm Electrode pad spacing 20mm Slit nozzle gap 5mm Pad width 1200mm Pad arc angle 180 ° Electrode material Pt plating on Ti base material

(Operating condition) Plate passing speed 50 to 1000 mpm Current density 100 A / dm ² Plate material size Width 1000 × thickness 0.2 mm Tension 1 kgf / mm ² Nozzle flow velocity of electrolytic solution Nozzles 2a and 2e in FIG. 1: 3 m / s , Nozzles 2c and 2g:
2m / s, all other nozzles are 1m / s

(Electrolyte solution) The following two types of multilayer plating were carried out (the solution temperature was 50
° C.) layer zinc - iron alloy _{plating: ZnSO 4 · 7H 2 O 200g} / l Na 2 SO 4 50g / FeSO 4 · 7H 2 O 150g / l lower Zinc - Iron alloy _{plating: ZnSO 4 · 7H 2 O 250g} / l Na ₂ SO ₄ 50 g / FeSO ₄ .7H ₂ O 380 g / l When two-layer electroplating of the strip was performed under the above-mentioned conditions, as shown in FIG. 2, the desired two-layer zinc-iron alloy plating was obtained in the cross section of the strip. Layers 10 and 11 are obtained,
It was confirmed that the adhered amount was also uniform.

[0017]

As described above, according to the plating method of the present invention, it is possible to efficiently obtain a metal strip having a plurality of plating layers in one running line, correct the shape defect of the strip, and strip and electrode. Since the distance between the electrode and the strip can be kept constant, good electroplating work can be performed even if the distance between the electrode and the strip is small, without uneven plating deposits or scratches due to contact between the strip and the electrode. . The present invention also allows for multi-layer electroplating on both sides of the strip simultaneously and at high current densities.

[Brief description of drawings]

FIG. 1A is a sectional view showing the principle of a plating line and an example of equipment for carrying out the method of the present invention. (B) is a partial explanatory view.

FIG. 2 is a strip cross-sectional view showing a plated portion of a multi-layer obtained by the present invention.

[Explanation of symbols]

 1 Electrode Pad 2 Electrolyte Injection Nozzle 3 Metal Strip 4 Discharge Pipe 5 Seal Roll 6 Conductor Roll 7 Electrolyte Tank 8 Electrolyte Discharge Hole 9 Liquid Cutting Roll 10, 11 Plating Layer

Claims (2)

[Claims] 1. A metal strip running line is bent into an arc shape, and electrode pads facing each other are sandwiched along the arc-shaped portion, and an electrolytic solution is caused to flow between the electrode pad and the strip for electroplating. In doing so, the electrode pad is divided into a plurality in the strip advancing direction so that the electrolytic solution does not infiltrate into adjacent sections at the divided portions,
A method for continuous electroplating of metal strips, characterized in that a plating solution is independently blown between each strip of electrode pads to form a plurality of plating layers on the strip surface. 2. The electroplating method according to claim 1, wherein an electrolytic solution is sprayed from each end of each divided electrode pad to generate a static pressure between the pad and the strip, and the strip is held stably.