JPS59215495A - Radial cell type electroplating device - Google Patents

Abstract

PURPOSE:To prevent defective plating owing to local stirring of a plating soln. in a cell by providing a slit-shaped plating soln. introducing nozzle so as to face the passage between anodes and masking the anodes right under a conductor roll. CONSTITUTION:A radial cell type plating device plates a strip 1 which travels in synchronization with the rotation of a conductor roll 3 in contact with the outside circumference thereof between anodes 5 and 5' spaced at a conducting gap (g) in the radial direction from the strip 1 by conducting electricity via the plating soln. introduced into the gap (g). A slit-shaped plating soln. introducing nozzle 10 communicating with a bottom nozzle 7 provided in the bottom of a plating cell 4 and extending in parallel with the axial direction of the roll 3 is provided to face the passage between the anodes for introducing the plating soln. formed right under the roll 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a radial cell plating apparatus, particularly for Zn-Ni, Z by improving the flow of the plating solution.
We propose an electroplating apparatus that is particularly suitable for plating alloys such as n-Fe.

In recent years, electrogalvanizing lines have come to play an important role as manufacturing equipment for automotive steel sheets. In particular, Zn-Ni, Zn- which is used to improve corrosion resistance
For producing alloy plating such as Fe, there is no other effective technique other than using the electrogalvanizing line. Moreover, in alloy plating, it is generally very difficult to obtain a film with a uniform plating composition.

Recently, radial cell electroplating equipment using a soluble anode has been used as an excellent plating technology because it can secure a higher current density force than ordinary zinc plating. The problem with this method is that it is difficult to adjust the liquid flow.

In other words, the conventional radial cell type bag cylinder with a kick-off plate has the first
As shown in Figures and Figure 2, the plating solution is ejected from the bottom nozzle installed at the center of the bottom of the tank (plating tank), collides with the conductor roll, and is formed between the zinc anode and the conductor roll. Flows upward through the current carrying gap. In the case of alloy plating, it is generally very susceptible to the influence of the flow rate of the plating solution, and unless a uniform liquid flow is formed on the strip surface, a predetermined alloy component ratio cannot be obtained. In particular, Zn-Fe alloy is remarkable,
Usually the ratio of 2n//Fe is 75~80/25~. It is said that the corrosion resistance is good when the Zn content is about 0.0, but for example, when the liquid flow rate is high, the Zn component increases. On the other hand, in the plating tank, especially at the liquid introduction part, the liquid may be stirred, and if this tendency is strong, abnormal plating may occur in which almost no Fe plating occurs and only Zn precipitates on the strip surface. There are easy negative effects.

The radial cell type plating equipment immerses a large diameter rotating drum (conductor roll 8) in a plating solution to an electric current level.
While a metal strip (hereinafter simply referred to as the strip) is brought into contact with the outer periphery of the conductor roll and is run in synchronization with the rotation of the conductor roll, the plating is carried out between the metal strip and an anode installed across a radial conduction gap from the conductor roll. This is a type of plating that applies electricity through a liquid, as shown in Figures 1 and 2.
The figure is a general illustration of the device.

The strip 1 passes through an inlet deflector roll 2, is wound around a conductor roll 8 1800 times, and leaves the coating bath 4 via an outlet deflector roll 2'. A soluble zinc anode 5,5' is slidably mounted on the anode support (5,6').

The plating solution is supplied into the tank from a bottom nozzle 7 provided at the bottom of the plating tank 4, and an anode is formed between the inlet and outlet anodes 5.5' for introducing the plating solution into the bending gap I. M1 flows through the current-carrying gear g through a passage p, and is led out of the tank from an overflow weir 8 at the top. In this apparatus, the bottom nozzle 7 is usually about 200 wφ and is installed approximately at the center of the bottom of the tank in the roll axis direction, and is opened facing the anode passage p. The purpose has been sufficiently achieved. In addition, the anodes 5 and 5' have a width of 1 mm for ease of handling.
It is produced in the 60th rank.

The gap between the front anode 5.5' and the strip 1 wound around the conductor roll 8 is kept constant so that the plating voltage is minimized. In order to achieve this, the pregnant anode support 6.6' is inclined so that it approaches the center line of the roll axis of the conductor roll 8 in the anode movement direction, so that the energization gap J is always constant. It is considered that there is.

At that time, the play angle is such that the anode 5, 5' is depleted by a predetermined amount due to plating, and in order to compensate for the consumed amount, the predetermined consumption amount/a/to width is It's been a minute.

In electrogalvanizing, increasing the current density by increasing the flow rate of the plating solution near the strip 1 is a generally well-known method, and even in the case of a radial cell type using a soluble anode, This effect is achieved by discharging a large amount of plating solution through the bottom nozzle 7 at the bottom of the plating tank 4.
High-speed plating is possible at a high current density of 0 A/dm2 or higher.

However, in alloy plating where two or more metals such as Zn-NirZn-Fe are plated at the same time, there is a strong relationship between the flow rate of the plating solution near the strip 1 and the alloy composition ratio. It is undesirable if there is a part where the liquid flow rate is different from other parts. For example, there is a phenomenon in which the liquid flow rate is disturbed in the vicinity of the p section of the inter-anode passage, making normal alloy plating impossible.

The purpose of the present invention is to overcome the plating defects caused by such local agitation of the plating solution within the tank. A slit-shaped plating solution introduction nozzle is provided facing the passage between the anodes, and as will be described later, the anode in the passage directly under the conductor roll, which is prone to strong agitation, is masked (the introduction nozzle and anode are separated from each other). By overlapping some areas), a particularly effective apparatus for alloy plating was provided, and the above-mentioned drawbacks were solved. The details of the configuration will be explained below.

8 to 5 are diagrams of preferred embodiments of the apparatus of the present invention, and reference numerals 1 to 8 in the drawings are the same as those of the conventional apparatus. 9 is a bender connected to the bottom nozzle 7, which directs the plating solution flow in the roll axis direction (strip width direction).
Used for uniform dispersion. A plating solution introduction nozzle lO whose upper end is connected to the inter-anode passage p is connected to the bottom nozzle 7 via this header 9. With these structures, the plating solution introduced into the tank through the bottom nozzle 7 flows smoothly into the current-carrying gear g at a constant speed.

The plating solution introducing nozzle 10 is a slit-shaped nozzle extending in the direction of the roll axis of the conductor roll, and because of this nozzle 1o, the plating solution is evenly supplied in the width direction of the IJ tube for uniform plating. Function effectively.

FIG. 5 shows details of the connection between the plating solution introduction nozzle 10 and the inter-anode passage p.

At the upper end of the plating solution introduction nozzle lO, plungers lOa and 10'a are protruded from the outer and outlet sides of the strip l, respectively, and these parts are connected so as to overlap with the recesses provided on the inner surface of the anode. This is to prevent plating from occurring in this region 2, where the stirring effect is large as described above. Furthermore, in order to make the liquid flow smoothly, the nozzle l
The upper end discharge portion has a structure that expands at an angle θ (70 to 90 degrees).

Regarding the structure of the above-mentioned grinding part, in order to avoid the following problems that occur when using a soluble anode, the four anode parts 5a and the nozzle flanges 10a, l are
A clearance C of about 11Rm is provided between it and O'a. At the same time, since the plating solution flows through this clearance C, the tips (recesses) of the anodes 5, 5' are worn out, allowing the anodes 5.5' to move on the ports 6, 6'.

That is, the anodes 5, 5' are gradually consumed from the surface as the plating time passes, and the amount of consumption is 4I111.
When it reaches about L, the anodes 5, 5' are adjusted to adjust the electrode distance.
is moved by the width equivalent (1fl Omm).

However, since the anode support 6.6' is inclined with respect to the roll axis, each time it is moved, 2J~
8 Approach the conductor roll 8 surface.

Therefore, in order to take this into consideration and maintain a constant energized gear y/, the clearance C must be at least 8mm at the start of the movement, and about 1a at the end of the movement (ensuring plating solution flow; (and the gap y that pushes up the flange portion changes as the anode tip no longer melts). At this level, there will be no problem with plating.

As explained above, according to the present invention, it is possible to achieve an appropriate flow of the plating solution, thereby obtaining uniform plating and an alloy plating layer having a uniform morning sickness composition.

[Brief explanation of drawings]

1-2 are explanatory diagrams of a conventional radial cell type electroplating apparatus, FIG. 1 is a front view thereof, FIG. 2 is a side view thereof, and FIGS. 8-5 are explanatory diagrams of the apparatus of the present invention. 8 is a front view, FIG. 4 is a side view, and FIG. 5 is a sectional view showing details of the upper end portion of the plating solution introduction nozzle. 1...Strip 2.2'...Deflector roll 8...Conductor roll 4...Plating tank 5.5'...Anode 5a, 5'a...Anode recess 6.6 '...Anode support 7...
・Bottom nozzle 8゛°・Overflow weir 9... Header 10... Plating solution introduction nozzle 10a + 10'a... Flange I of plating solution introduction nozzle... Currency gap 0... clearance. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] 1. A strip that is in contact with the outer periphery of the conductor roll and runs in synchronization with its rotation, is inserted into the gap between the IJ tube and the anode that separates the radial current-carrying gap. In a radial cell type plating apparatus that performs plating by applying electricity through a liquid, a roll axial direction that faces the anode-to-anode passage for introducing the plating liquid formed directly below the conductor roll and communicates with a bottom nozzle provided at the bottom of the tank. A radial cell electroplating device characterized by having a slit-shaped plating solution introduction nozzle extending parallel to the radial cell type electroplating device.