JPS62103392A - Continuous electroplating method for metallic strip - Google Patents

Abstract

PURPOSE:To form a plating having a uniform thickness in the transverse direction of a metallic strip on said strip without an over-coat and under-coat in the stage of subjecting the surface of the strip to continuous plating by providing freely movable auxiliary cathodes in proximity to the ends of the strip and moving the auxiliary cathodes in such a manner that the currents flowing in both auxiliary cathodes are made equal. CONSTITUTION:Electricity is conducted between the metallic strip 4 and anodes 9 disposed on both sides of the strip 4 via a cathode conductor roll 2 to plate the surface of the strip 4. The auxiliary cathodes 10, 10' are disposed in proximity to both ends of the strip 4 and the spacing from the strip 4 is made changeable by position adjusting mechanisms 11, 11'. The currents flowing in both auxiliary cathodes 10, 10' during the plating operation are inputted to a differential calculator 17 by which the difference between the currents is calculated. The output from the differential calculator 17 is inputted to an auxiliary cathode position adjuster 18 if there is the difference between both currents. The auxiliary cathodes 10, 10' are so moved by the difference in the current values that the currents of both auxiliary cathodes 10, 10' are made equal. The generation of the over-coat and under-coat in the plating layer of the strip 4 is thus prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention is directed to over-plating, in which the amount of plating at the edges of the metal strip is greater than that at the center, when continuously electroplating a metal strip such as copper or aluminum. The present invention relates to a continuous electroplating method for metal strips, which does not produce a coating or an undercoat in which the amount of plating is smaller than in the central part, and can be evenly and uniformly plated in the width direction of the metal strip. .

[Prior art and its problems]

For example, for continuous electroplating of steel strip,
There are two methods: a method of plating using a vertical electroplating device as shown in FIG. 3, and a method of plating using a horizontal electroplating device as shown in FIG. As shown in FIG. 3, the vertical electroplating apparatus includes conductor crawls 2 and 2' provided above the inlet and outlet sides of the IJ horn, and the electroplating tank 1. The zinc roll 3 and fundactor roll 2 provided at the bottom of the
・A pair of vertical electrode plates arranged parallel to the steel strip 4 in the electroplating tank 1 between each of the steel strips 2' and the zinc roll 3, with the steel strip 4 moving in the electroplating tank 1 Consisting of 5, 5' and 6, 6' (・ru. copper su) IJ
The tube 4 moves downwardly and then upwardly in the electroplating bath 1 in which the plating bath is contained and flowing, while passing a pair of electrode plates 5, 5' and 6.6'. is continuously electroplated.

As shown in Fig. 4, the horizontal electroplating apparatus includes conductor rolls 2, 2' provided on the outside of the IJ tube entry and exit sides, and an electric (steel steel in plating tank 7) IJ tube inlet and outlet frill
A pair of L lower dam rolls 8a, 8a' and 8b, 8b' provided in K, and dam rolls 8a, 8a' and 8b, 8b.
A pair of horizontal electrode plates 5° 5' are placed parallel to the steel strip 4 with the IJ knob 4 between them. The steel strip 4 moves in an electroplating tank 7 in which a plating bath is contained and flowing, and is connected to a pair of electrode plates 5, 5' and 6, 6'. It is continuously electroplated while passing through.

The reason why the IJ strip 4 is opened and closed when electroplating both sides of the IJ strip 4 in this way is that the plating current concentrates on the edge of the IJ strip 4, and the edge of the IJ strip 4 is This is the occurrence of an overcoat in which the amount of plating is greater than in other parts.

When electroplating one side of the strip 4, as shown in Figure 6, in addition to overcoating the edges as described above, a problem arises in which the current flows around the non-plated side and causes plating. do.

In this way, if an overcoat occurs on the edges of the steel strip, when the steel strip is wound into a fill shape,
A build-up phenomenon occurs in which the edges swell, causing the plating films on the overcoat parts to rub against each other, resulting in scratches, poor welding strength of the overcoat part during welding, and poor appearance due to discoloration of the overcoat part. An open chain occurs.

Therefore, in order to prevent the above-mentioned chain opening,
As shown in Fig. 8 and Fig. 8, the main electrode plate 9
, 9' length and a narrow auxiliary electrode plate]0
．． 10', main electrode plate 9.9' and auxiliary electrode plate 10
．． By passing a plating current between the auxiliary electrode plate 10 and 10', the plating current concentrated on the outer edges of the row strip 40 is collected on the auxiliary electrode plate 10 and 10'.
A method has been developed to prevent overcoating from occurring on the edge portion of the J-tube 4 and to prevent plating on the non-plated surface in the case of single-sided plating.

According to the above-mentioned method, overcoating that occurs on the edges of the IJ tube (steel steel) can be prevented, but conversely, undercoating that occurs on the edges is less than other areas, and
(When the strip meanders in its width direction and the relative distance between the edge of the steel strip and the auxiliary plate changes,
A problem arises in that the current distribution at the edge portion fluctuates, resulting in uneven plating at the edge portion.

Figure 9 shows a pair of main electrode plates 9.9 as shown in Figure 10.
′) near the edge of IJ knob 4,
steel) Place the auxiliary electrode plate 10 parallel to the IJ knob 4,
steel strip) When electroplating is applied to the steel strip 4 by changing the distance between the edge of the IJ tube 4 and the edge of the auxiliary electrode plate 10, the distance between the edge of the steel strip 4 on one side is This is the tin adhesion rate. In Figure 9, ○ marks indicate that L is JOmrn, and Δ marks indicate that L is 25 nm.
In the case of , the cross mark indicates the case where L is sowm, and the @ mark indicates the case where the auxiliary electrode plate 9 is not arranged. As shown in the drawing, when L is 1 oin, an undercoat occurs in which the tin deposition at the edges is reduced by about 15% compared to the center.

[Purpose of the invention]

Therefore, an object of the present invention is to prevent overcoat and undercoat from forming on the edges of the metal strip during electroplating on metal IJ tubes, and to prevent uneven plating from occurring even when the metal strip meanders in its width direction. To provide a method for continuous electroplating of a metal strip, which can always apply a uniform amount of plating in the width direction of an IJ tube.

[Summary of the invention]

The present inventors have proposed a method for preventing overcoat from forming on both edges of a metal strip by placing auxiliary electrode plates close to both edges of a metal strip that is being moved in an electroplating bath. We have conducted extensive research to solve the above-mentioned problems that arise.

The present inventors first investigated the relationship between the distance between the edge of the metal IJ tab and the edge of the auxiliary electrode plate and the current flowing through the auxiliary electrode plate. Figure 11 is a graph showing the relationship between the position of the auxiliary electrode plate and the current flowing through the auxiliary electrode plate. 100% current value
The horizontal axis is the distance between the edge of the metal strip and the edge of the auxiliary electrode plate. As shown in FIG. 11, it has been found that as the distance between the edge of the metal strip and the edge of the auxiliary electrode plate increases, the value of the current flowing through the auxiliary electrode plate decreases.

Next, the relationship between the voltage value and current value of the auxiliary electrode plate was investigated.

Figure 12 is a graph showing the relationship between the current flowing through the auxiliary electrode plate and its voltage when the distance between the metal IJ lug edge and the edge of the auxiliary electrode plate is 25 mm, and the vertical axis is The ratio of the current flowing to the auxiliary electrode plate when the plating current value flowing to the center of the IJ tube is taken as 100%. The horizontal axis is the ratio of the voltage of the auxiliary electrode plate to the voltage of the main electrode plate. be. As shown in FIG. 12, it was found that as the voltage of the auxiliary electrode plate was increased, the value of the current flowing through the auxiliary electrode plate decreased.

From the above, there is a correlation between the voltage and current of the auxiliary electrode plate and the distance fiL between the edge of the auxiliary electrode plate and the edge of the metal strip.If the voltage is fixed, the current will change as L changes, It has been found that if the current is kept constant, the voltage changes as L changes.

The present invention is based on the above findings, and includes continuously guiding a metal strip into an electroplating tank containing a plating bath in which at least one electrode plate is arranged.
In a continuous electroplating method for a metal strip, in which the surface of the metal strip is continuously plated while the metal strip passes through the electrode plate, the electrode plate is arranged in the plating bath. Where you are,
metal strips passing through the plating tank) Auxiliary electrode plates are arranged movably in the width direction of the metal strip in proximity to both edges of the IJ tube, and between each of the auxiliary electrode plates and the electrical barrier plate. By passing an electric current through the metal (IJ)
In addition to preventing an overcoat from occurring on both edges of the tube, continuously detecting the difference in current value or voltage value between one and the other of the auxiliary electrode plates so that the difference becomes zero,
The present invention is characterized in that each of the auxiliary electrode plates is moved in the width direction of the metal strip to control its position.

[Structure of the invention]

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of continuous electroplating of steel IJ tubes using a vertical electroplating apparatus according to the method of the present invention.

As shown in the drawing, a pair of vertical main electrode plates are placed in parallel with the IJ tube 4, with the steel tube being guided by the fundactor roll 2 and moving in the electroplating tank with the IJ tube 4 in between. 9
(Only one of them is shown in the drawing. Board 10.10
' is placed. Each of the auxiliary electrode plates 10, 10' has a position adjustment mechanism 11, 11. 'by steel strip 4
It is movable in the width direction of the steel strip 4 so that the distance between the gills and the gills of the steel strip 4 can be controlled.

The main electrode plate 9 is connected to the anode side of a power source (not shown), and is also connected to the fundactor roll 2. is connected to its cathode side, and the steel strip 4 is energized by the conductor roll 2.

The auxiliary voltage plates 10, 10' are connected to the conductor roll 2 via a voltage regulator 14. Auxiliary electrode plate 10.
10' is at the same potential. 12.12' is a current collector attached to the shaft of the conductor roll 2.

In the middle of the conducting wire 13 connecting each of the current collectors 12, 12' and each of the auxiliary electrode plates 10, 10', there is a voltage regulator 14,
A current detector 15.15' is provided for detecting the current value flowing through each of the auxiliary electrode plates 10.10'.

Auxiliary electrode plate 10 detected by current detector 15.15'.
The current values flowing through each of the terminals 10' are input to a difference calculator 17 through conducting wires 16 and 16', and the difference is calculated by the difference calculator 17. The difference value calculated by the difference calculator 17 is sent to the auxiliary electrode plate position adjuster 18, and the auxiliary electrode plate position adjuster 18 sends a position adjustment signal to the position adjustment mechanism 11° 11' via a conductor 19, 19'. send.

According to this embodiment, the auxiliary electrode plates 10.10 at the same potential
44=4=current flowing through each of the current detectors 15.'
15', and are compared by a difference calculator 17 to calculate the difference.

If there is a difference in the current value flowing through each of the auxiliary electrode plates 10 and 10', it is determined that the IJ knob 4 is meandering, and the auxiliary electrode plate position should be adjusted so that the difference becomes zero. The position adjustment mechanism 11.11' is activated by the signal from the device 18, and the auxiliary electrode plate 1.0.10' is moved to the IJ knob 4.
Move it in the width direction to correct its position.

FIG. 2 is an explanatory diagram showing another embodiment of the invention. Each of the auxiliary electrode plates 10.10' has a position adjustment mechanism 11.
．． As described above, '11' allows the steel strip to move freely in the width direction of the IJ tab 4 so as to control the distance between the edge and the edge of the IJ tab 4.

Each of the current collectors 12, 1.2' and the auxiliary electrode plate 10.10'
A voltage regulator 14.14' and a current detector 15.15' are provided in the middle of the conducting wire 13.13' connecting each of the two. Current controllers 20 , 20 ′ are connected to each of the voltage regulators 14 , 14 ′, and a current detector 15
, 15' and the current controller 20, 2 Q' are conductors, J
21, 21'.

In advance, the edge of the steel strip 4 flows to the auxiliary electrode plates 10, 10' corresponding to the appropriate distance between the edge of the copper strip 7° 4 where overcord and undercoating do not occur and the auxiliary electrode plates 10, 10'. '1 DC value is determined and this current value is input to the current controller 20, 20'.

On the other hand, the current value flowing through the auxiliary electrode plates 10 and 10' is continuously detected by the current detectors 15 and 15', and the detected current value is passed through the conductors 21 and 21' and is then passed through the current controller 2.
0, 20'. Current controller 20
, 20' compares the detected current value that has been fed back and a predetermined current value that has been input in advance, and sends a signal to the voltage regulator 14, to make the difference between the detected current value and the predetermined plating current value zero. Send to 14'.

The turtle E adjusters 14 and 14' are current controllers 20 and 20.
The voltage of the current flowing through the auxiliary electrode plates 10 and 10' is adjusted based on the signal from the auxiliary electrode plates 10 and 10', thereby controlling the undercurrent value to a predetermined value.

The auxiliary electrode plates 10 and 1 varied by such control.
The voltage value of the current flowing through 0' is input to the difference calculator 17 through the conducting wires 22 and 22', and the difference is calculated by the difference calculator 17. The difference value calculated by the difference calculator 17 is sent to the auxiliary electrode plate position adjuster 18, and the auxiliary electrode plate position adjuster 18 adjusts the position to the position adjustment mechanism 11° 11' using the 24 wires 19 and 19'. send a signal.

According to this embodiment, each of the auxiliary electrode plates 10, 10' has a constant value of '', regardless of the change in the distance between the edge of the pot strike IJ 7'4 and the auxiliary electrode plates 10, 10'.
A difference calculator 17 calculates the difference in voltage value between the auxiliary electrode plates 10 and 10' that occurs when one current flows.

If there is a difference in the voltage, then the steel strip 4
is determined to be meandering, and the difference becomes zero,
In response to a signal from the auxiliary electrode plate position adjuster 18, the positioning mechanism 11°11' is operated to move the auxiliary electrode plates io, io' in the width direction of the support graph 04 to correct their positions.

In each of the embodiments described above, it is preferable to use the difference@calculator 17 having a certain dead zone area in order to fully stabilize the ij control. Auxiliary electrode plate 10
, 10' position rA M mechanism 11 for adjusting the position
, 11' may use, for example, a hydraulic cylinder or other appropriate moving mechanism. In addition, 'voltage regulator 14
, 14' may be anything other than a thyristor stack that can change the voltage and have a current capacity.

By controlling as described above, the copper strip f4
Is it meandering and the edge of copper strip f4? Even if there is a change in the distance between it+auxiliary electrode plates 10, 10', the auxiliary 'α electrode plates 10, 10' move to follow this change, thereby always keeping the distance constant. Therefore, overcoat and undercoat occurring on the edge portion of the kite strip 4 can be properly prevented.

For example, when continuous tin plating is applied to a copper strip using a vertical type electroplating apparatus, if the Fukusuke electrode plate is not placed, the other electrode is placed between 30 mm from the edge of the strip. There is 94% more plating poison than the other parts, and an overcoat occurs at °C, but due to the arrangement of the auxiliary electrode plate,
Overcoat could be prevented. On the other hand, in the above portion, on the contrary, the amount of plating was 14% lower than in other portions, and undercoating and uneven plating occurred. However, according to the method of the present invention, undercoat is completely prevented, and furthermore, even if the IJ knob meanders more than 15 mm from side to side, the auxiliary electrode plate will follow this and move. There was no variation in the amount of plating on the edges, and no uneven plating occurred.

In addition, when applying continuous single-sided electrogalvanization to only the bottom surface of a steel strip at a point 10 mm below the bath surface of the plating bath using a horizontal electroplating device, conventionally, 25 mm from the edge of the top surface of the copper strip was applied. However, according to the method of the present invention, underfoot does not occur on the edge of the bottom surface, and the plating that occurs on the edge of the top surface is also plated between the edge and the edge. was able to be reduced to

〔Effect of the invention〕

As described above, according to the present invention, when continuously electroplating a metal strip using a vertical electroplating device or a horizontal electroplating device, an overcoat or an undercoat is applied to the edge of the metal strip. No coating occurs, and even if the metal strip meanders in the width direction, there will be no uneven plating, and a uniform amount of plating can always be applied in the width direction of the IJ tube.This is an industrial advantage. is brought about.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of continuous electroplating using a vertical electroplating apparatus according to the method of the present invention; FIG. 2 is an explanatory diagram showing another embodiment;
The figure is a schematic vertical cross-sectional view of a vertical electroplating device, FIG. 4 is a schematic vertical cross-sectional view of a horizontal electroplating device, and FIG. Figure 6 is an explanatory diagram showing how current flows to the non-plated surface in the case of single-sided plating, Figures 7 and 8 are explanatory diagrams showing the distribution of plating current when an auxiliary electrode plate is arranged, and Figure 9 Figure 10 is a graph showing the relationship between the distance between the edge of the IJ tube and the auxiliary electrode plate and the amount of plating on the edge of the IJ tube. Figure 11 is a graph showing the relationship between the position of the auxiliary electrode plate and the current flowing through the auxiliary electrode plate, and Figure 12 is a graph showing the relationship between the current flowing through the auxiliary electrode plate and its voltage. It is a graph showing the relationship. In the drawings, 1... Vertical electroplating tank, 2. 2'... Conductor roll, 3... Zin roll, 4... Sake strip, 5
, 5', 6.6'... Electrode plate, 7... Horizontal electroplating bath, 8a, 8a', 8b, 8b'-... Dam roll, 9.9'... Main electrode plate, 10 .10'...
Auxiliary electrode plate, 11.11'... Position adjustment mechanism, 12.12'... Current collector, 13.13'... Conductive wire, 14.14'... Voltage regulator, 15.15'. ...Current detector, 16.16'...Conductor, 17...Difference calculator,
18... Auxiliary electrode plate position adjuster, 19.19'... Leading wire, 20.20'... Current controller, 21.21', 22.22'... Leading wire.

Claims (1)

Claims: A metal strip is successively guided into an electroplating tank containing a plating bath in which at least one electrode plate is arranged, while the metal strip passes through the electrode plate. In a continuous electroplating method for a metal strip in which the surface of the metal strip is continuously plated, at a position in the plating bath where the electrode plate is arranged,
auxiliary electrode plates are arranged movably in the width direction of the metal strip in proximity to both edges of the metal strip passing through the plating bath, and a current is passed between each of the auxiliary electrode plates and the electrode plate. This prevents an overcoat from occurring on both edges of the metal strip, and continuously detects the difference in current or voltage value between one and the other of the auxiliary electrode plates so that the difference becomes zero. . A continuous electroplating method for a metal strip, characterized in that each of the auxiliary electrode plates is moved in the width direction of the metal strip to control its position.