JPS6176698A - Device for controlling flow rate of plating liquid - Google Patents

Abstract

PURPOSE:To form a plating layer in the transverse direction of a steel strip to a uniform thickness in the stage of subjecting both surfaces of the steel strip traveling in an electroplating bath cell to electroplating by forming nozzles for supplying a plating liquid into between anode plate and the steel strip into specific construction. CONSTITUTION:The steel strip 1 as the cathode is run at a specified speed between 1-2 pairs of the anodes 14 in the electroplating cell of a horizontal or vertical type, etc. and the plating bath is supplied into between the anodes 14 and the steel strip 1 which is the cathode from the nozzles 16 of a header 15. Electricity is conducted between both electrodes and the surfaces of the steel strip 1 as the cathode are electroplated. The nozzles 16 for supplying the plating liquid are connected from liquid feed pipes 19 divided to plural pieces from the header 15 via flow rate regulating valve 18 and flow regulating plates 17 interposed in the midway in order to form the plating layers to a uniform thickness over the entire surfaces on both sides of the steel strip. The flow rate of the plating liquid is made uniform in the transverse direction of the steel strip 1 and the plating layers are formed uniformly over the entire surface of the steel strip 1 by using such nozzles 16.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is capable of uniformly supplying a plating solution at a rate of 7 IJ in the width direction of the strip between the anode of the plating cell section and the strip in an electroplating line for steel sheets. The present invention relates to a header and nozzle for flow rate adjustment.

The present invention was developed for the purpose of providing a header and a nozzle that can uniformly control the flow rate of a plating solution in the width direction of a strip in a plating tank.

Figure 1 shows an example of an electroplating line for steel sheets. A strip 1 is discharged from a payoff reel 2, and impurities such as oil and fat adhering to the strip surface are cleaned in a degreasing tank 6 and a pickling tank 7. Thereafter, it is plated in a plating tank 8, passed through a post-treatment device 9 for rust prevention, etc., and wound up on a tension reel 12, completing the plating process.

FIGS. 2 to 4 show examples of plating baths.

FIG. 2 shows a horizontal cell, FIG. 3 shows a vertical cell, and FIG. 4 shows a radial cell. That is, the running metal strip 1 is charged as a cathode, and a plurality of plate-shaped or rod-shaped electrodes 14 provided opposite to the metal strip 1 at right angles to the running direction are charged as cathodes, and the metal strip 1 is charged as a cathode.
A plating bath in a recent electroplating line is a device that supplies a plating solution from a plurality of nozzles 15 disposed between a metal strip 1 and an anode 14 to deposit plating metal on the metal strip 1. There are two types of anodes: soluble anodes that elute plating metal ions into the plating solution, and insoluble anodes that do not elute plating metal ions into the plating solution.

In general, the weight of the plated metal deposited on the surface of the metal strip is determined by line speed, current density, plating solution flow rate, etc., but in recent years high-efficiency electroplating lines, all of the above parameters have relatively high values. The line speed is ~250 shoes/1n, the current density is ~200A/dm', and the plating solution flow rate is W 5 m.
/sec.

Here, in terms of plating quality, it is necessary that the basis weight of the plating metal be uniform across the width direction of the metal strip. Since the current density at the edge of the strip is higher than other parts, the plated metal is likely to be overcoated, but recently various edge mask devices have been devised and put into practical use to prevent this. It's coming.

On the other hand, if the plating solution is not sprayed at a uniform speed in the width direction of the metal strip, it will cause an imbalance in the basis weight.

FIG. 5 shows an example of a conventional plating solution nozzle. The plating solution is passed through the solution supply header 15 and from the nozzle 16 between the strip L and the anode 14 to remove 02 gas etc. generated during plating. For purposes of relatively high flow rates (1 to 5 m
/sec).

Figures 6 to 8 show cross sections of the nozzle seen from the direction A-A in Figure 5. Figure 6 shows a nozzle with a constant cross-sectional area in the width direction, and Figure 7 shows a nozzle with a constant cross-sectional area in the width direction. FIG. 8 shows a nozzle that is narrow and has a wide cross-sectional area at both ends, and a nozzle that is divided in the width direction (the cross-sectional area is constant or variable).

Conventional devices suffer from the disadvantage that the plating solution flow rate in the nozzle width direction becomes non-uniform due to the pressure loss in the nozzle width direction. That is, in the nozzle with a uniform cross section shown in FIG. 6, the plating solution flow rate at the center of the nozzle tends to be higher than the plating solution flow rate at both ends of the nozzle. In addition, with the nozzle shown in Figure 7, a relatively uniform flow rate may be obtained with a metal strip of a certain thickness, but if the thickness or width of the metal strip changes, the anode and metal B) Since the cross-sectional area distribution in the width direction between the IJ tubes changes, the plating solution flow velocity distribution in the board width direction changes, so it has the disadvantage that it cannot be applied to metal strips of various sizes. Further, the device shown in FIG. 8 also has the same problem as above.

In the electroplating line near Fi, the interpolar distance between the anode and the metal strip is oriented to low power loss, high current density,
There is a tendency for the width to be reduced to about 10 to 20 mm, and it is becoming increasingly difficult to obtain a uniform flow velocity in the width direction of the plate.

<Objective of the Invention> The present invention aims to solve the various problems mentioned above, and in particular provides a plating solution flow rate control device that can make the plating solution flow rate uniform in the width direction of the strip to be plated. The purpose is to

<Configuration of the Invention> According to the present invention, a running metal strip is charged as a cathode, an electrode provided facing the metal strip is charged as an anode, and at least one electrode disposed between the metal strip and the anode is charged. In a continuous electroplating line in which plating solution is supplied from multiple nozzles to deposit plating metal onto a metal strip, multiple liquid supply pipes are branched from the ladder to the plating solution supply corresponding to the nozzle. A flow control valve is installed on the upstream side of each of these branched liquid supply pipes, a wave regulating plate is installed on the downstream side, and the other ends of the plurality of liquid supply pipes are connected in the width direction of the plating liquid inlet side of the nozzle. A plating solution flow rate control device is provided, which is characterized in that the two devices are connected to each other.

The present invention will be explained in more detail below.

Structure of the ladder and nozzle for plating solution injection of the present invention,
That is, the plating solution flow rate control device is shown in FIGS. 9 and 10.
9 shows a side view of the apparatus of the present invention, and FIG. 10 shows a BB parent view of FIG. 9, respectively.

The plating solution is distributed and supplied from the header 15 through the flow rate 7AyB valve 18 from the liquid supply pipe 19 divided into a plurality of parts in the width direction, and by providing a rectifying plate 17 in each liquid supply pipe 19, each The flow rate distribution within the liquid supply pipe is made uniform, and the plating liquid is combined with the nozzle 16 made in one piece.

The number of divisions of the liquid supply pipe 19 from the header 15 may be arbitrarily selected depending on the width and thickness of the steel plate strip, but the greater the number of divisions, the easier it is to obtain a uniform flow velocity distribution in the width direction.

In addition, as the current plate 17, vinyl chloride, SUS
31.6, rubber lined products, etc. can be used.

Here, the plating solution generally uses a chloride bath for soluble anodes and a sulfate bath for insoluble anodes, and in both cases, the pH is low at 1 to 4 and corrosive. Since the plating solution flow rate control device of the present invention is a highly resistant liquid, it is necessary to use a lining made of FRP material, natural hard rubber, etc. By using these corrosion-resistant materials, the fire resistance against the plating solution is low. can be fully guaranteed.

Examples Fig. 11 shows actual measurement examples of the flow velocity distribution in the width direction when using the ladder and nozzle of the present invention and when using the conventional nozzle and header.

The experimental conditions were: nozzle width: l100Os, average flow rate of liquid v
: As a result of testing with the liquid supply pipe of the present invention set to 3 m/sec and the number of divisions of the liquid supply pipe of the present invention being 3, the liquid flow rate in the width direction of the conventional nozzle shown by the solid line in Fig. 6 was as follows. It can be seen that the nozzle of the present invention, indicated by the dotted line ■, has excellent controllability of the liquid flow rate of the header and nozzle. In addition, V
I+vl' is the lowest flow rate, v2. v2' is the maximum flow velocity 2 Also, when the nozzle and header of the present invention are applied to an electroplating line, and other plating conditions other than the liquid flow rate are kept the same, the basis weight of the plated metal in the width direction of the metal strip is As a result of investigating the variation in , it was within 5%, confirming the effectiveness of the nozzle and header of the present invention.

<Effects of the Invention> In the present invention, there is a plurality of liquid supply pipes from the header to the nozzle, and a flow rate 2j 1-node valve is provided on the upstream side of this liquid supply pipe.
By installing a current plate on the downstream side, the flow velocity of the plating solution can be made uniform in the width direction of the strip.

Furthermore, since the variation in the flow rate of the plating solution is reduced, the variation in the basis weight of the plating metal is also reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a general electroplating line. FIG. 2 is a diagrammatic cross-sectional view of a horizontal cell, FIG. 3 is a vertical cell, and FIG. 4 is a radial cell. FIG. 5 is a cross-sectional view of a conventional header and nozzle. FIGS. 6, 7 and 8 are A-A parent views of FIG. 5, and each shows a nozzle with a uniform cross-section in the width direction. FIG. 2 is a front view of a header and a nozzle having a widthwise variable cross-section nozzle and a widthwise divided nozzle. FIG. 9 is a sectional view of the plating solution flow rate control device of the present invention. FIG. 10 is a plan view of the plating solution flow rate control device of the present invention, viewed in the direction BB in FIG. 9. FIG. 11 is a graph showing the plating solution flow velocity distribution in the board width direction. Explanation of symbols 1...Strip, 2...Payoff reel, 3...
- Entrance shear, 4... Welder, 5... Entrance louver, 6... Degreasing device, 7... Pickling device, 8...
Plating tank, 9... Post-processing device, IO... Output side looper, 11... Output side shear, 12 φ fist tension paddle reel, 13... Conductor roll, 14... 7 nodes, 15... header, 16... nozzle, 17...
- Rectifying plate, 18...Flow control adjustment, 19...Liquid supply pipe FIG, 2 FIG, 11 Distance in width direction → FIG, 5

Claims (1)

[Claims] A running metal strip is charged as a cathode, an electrode provided opposite to the metal strip is charged as an anode, and a plating solution is supplied from at least one nozzle disposed between the metal strip and the anode, In a continuous electroplating line that deposits plating metal on a metal strip, multiple liquid supply pipes are branched from the plating liquid supply header corresponding to the nozzle, and a flow rate adjustment device is installed on the upstream side of each of these branched liquid supply pipes. A plating solution flow rate control device, characterized in that a valve is attached to a downstream side of a rectifying plate, and the other ends of the plurality of liquid supply pipes are connected in the width direction of the plating solution inlet side of the nozzle.