JP2000273689A - Metal strip plating method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure the uniformity of a plating coating weight in a transverse direction by dividing a soluble anode to divided anodes which are plural in a longitudinal direction and adjusting a masking range of the respective divided anodes. SOLUTION: For example, the soluble anode 30 is trisected to the divided anodes 31 in the longitudinal direction of the metal band 1 to be transported. The respective divided anodes 31 are placed on three rows of divided anode tables 32. Masks 33, which make the masking range adjustable, are arranged between the divided anodes 31 and the metallic band 1. The divided anodes 31 are trisected by the masks 33. The edge parts and the central parts are exposed and other parts are shielded. Positive voltage is impressed to the divided anodes 31 from a rectifier 7 to regulate the masking range of the divided anodes. The spacings between the respective divided anodes 31 and the metallic band 1 are regulated by independently lifting the divided anodes 31 by means of a divided anodes table lifting device 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to plating of a metal strip, and more particularly to a metal for plating using a soluble anode in which a plating metal ion is supplied to a plating solution used in a horizontal plating apparatus by an anode itself. The present invention relates to a band plating method and apparatus.

[0002]

2. Description of the Related Art In continuous plating equipment for metal strips, particularly steel strips, it is extremely important for quality control to ensure uniformity of the coating weight in the metal strip width direction. for that reason,
In continuous plating equipment, measures have been taken to measure and control the amount of plating applied and to make the plating uniform.

FIG. 4 shows an example of a continuous plating facility. The metal strip 1 is transported in the direction of the arrow. And the plating tank
The plating on one side is sequentially performed in 3a to 3h. Where 20
Indicates a soluble anode in the plating tank. When the plating on one side is completed, the transport direction is reversed by the roll, and then the plating on the other side is sequentially performed in the plating tanks 4a to 4h.

[0004] When the plating on both sides is completed, the metal band is turned over again, and the amount of adhesion is checked by the plating adhesion meter 6,
Subsequently, it is transported to the next step (not shown). The measurement of the adhesion amount with the plating adhesion meter 6 is usually performed in the width direction of the metal band.
Location, Op (operator side), Dr (drive side), C
e (center unit). Here, the structure of the conventional soluble anode 20 is shown in FIG. In FIG. 3, the description of the plating tank is omitted.

Anodes 21 are arranged in a row on a pair of main anodes 22 provided immediately below the metal strip 1 to be conveyed. The main anode 22 is connected to the rectifier 7 and applies a positive potential to the anode loaded immediately above. Here, the metal strip 1 is given a negative potential (or is grounded), and is used as a cathode (cathode).

In plating using a soluble anode, the anode is made of a metal to be plated (for example, tin) itself, and is supplied as a plating metal by being dissolved in a plating solution as ions. As a result, the anode gradually wears out, and if left untouched, the distance between the anode and the metal strip changes, posing a problem in quality control of plating. In order to compensate for the consumption of the anode, as shown in FIG.
While being arranged in a row on 22 and successively supplying new anodes, they are extruded in the width direction of the metal strip, and on the other hand, exhausted anodes are collected.

However, in such a method of moving the anode in one direction, the height of the anode is inclined from a new anode to the exhausted anode, and the amount of plating applied becomes non-uniform. For this reason, the direction in which the anode is moved is set to the opposite direction for each plating tank, so that plating is uniform throughout the plating equipment.

In the example of FIG. 4, the anode supply directions of the soluble anodes 20 in the plating tanks 3a, 3c, 3e and 3g and the plating tanks 3b, 3d, 3f and 3h are alternate directions. Also, similarly, 4a,
The anode supply directions of the soluble anodes 20 in the plating tanks 4c, 4e, 4g and the plating tanks 4b, 4d, 4f, 4h are also alternate directions. Other factors that hinder the uniformization of the coating amount in the width direction of the plating in the metal band include edge overcoat caused by current concentration at the edge of the metal band, and the difference between the anode and the cathode (metal band). Local adhesion due to current concentration on the nearest part due to the lack of parallelism can be raised.

Conventionally, as a measure against the edge overcoat, application of an edge mask can be cited. In this method, a non-conductive mask is arranged between an anode and a metal strip to suppress a current near an edge of the metal strip to prevent a current from concentrating on the edge (for example, Japanese Patent Laid-Open No. 5-339788). Gazette).

On the other hand, in order to prevent the parallelism between the anode and the metal strip from being maintained, the distance between the anode and the metal strip is stabilized by various methods (for example, see Japanese Unexamined Patent Publication No. 8-3786).

[0011]

However, an inevitable factor in using a soluble anode is that the anode is preferentially dissolved in the portion where the opposing metal band exists, and almost completely in the portion where the opposing metal band does not exist. It does not dissolve. There is no particular problem if the width of the metal strip to be treated in the plating equipment is always constant, but in practice, metal strips of various plate widths are transported and plated.

For this reason, the anode in the prior art tends to become thinner, especially at the central portion facing the metal band of all widths, and to have a prominent distribution without being worn at both ends. For this reason, it is unavoidable to avoid current concentration in the portion where the protrusion remains, and the plating becomes too thick in this portion.

[0013] From the above, in order to guarantee the minimum amount of plating, especially at the center of the metal strip, 3-5% by weight as a whole
It is necessary to perform a certain amount of excess plating. It is an object of the present invention to prevent the plating from becoming too thick due to the current concentration in the portion where the protrusion remains, and to reduce the above-mentioned excessive plating by making the plating uniform in the width direction.

[0014]

According to the present invention, in a method of plating a metal strip using a soluble anode, the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and each of the divided anodes is masked. The above problem was solved by a method of plating a metal band, which is characterized by adjusting the range and adjusting the amount of plating.

The present invention also provides a method for plating a metal strip using a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and the distance between each divided anode and the metal strip is reduced. The above problem was solved by a method of plating a metal band, which comprises adjusting the amount of plating and adjusting the amount of plating. Further, the present invention provides a method for plating a metal strip using a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and a masking range of each of the divided anodes is adjusted. The above problem was solved by a metal band plating method characterized by independently adjusting the distance between each divided anode and the metal band and adjusting the amount of plating.

Next, according to the present invention, in a metal strip plating apparatus provided with a soluble anode, the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and each of the divided anodes is masked. The above problem was solved by a metal strip plating apparatus having a mask capable of adjusting the range. Further, the present invention provides a metal strip plating apparatus provided with a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal strip, and each of the divided anodes is spaced apart from the metal strip. The object has been solved by a metal strip plating apparatus, which has an elevating device that can be adjusted independently.

Further, according to the present invention, in a metal strip plating apparatus provided with a soluble anode, the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and each of the divided anodes has a masking range. The above object has been solved by a metal band plating apparatus, which has a mask that can be adjusted, and further has an elevating device that allows each of the divided anodes to independently adjust the interval with the metal band. It is.

[0018]

1 shows a soluble anode 30 according to the present invention. In FIG. 1, the metal strip 1 to be conveyed is indicated by a two-dot chain line. In FIG. 1, the soluble anode 30 is a divided anode 31 divided into three in the longitudinal direction of the metal strip 1.

In the following, a case where the divided anode is divided into three parts will be described. However, the present invention is not limited to this. The divided anodes 31 are respectively loaded on three rows of divided anode tables 32. Between the divided anode 31 and the metal strip 1,
A mask 33 that can adjust a masking range is provided. In the example shown in FIG. 1, the metal strip is divided into three parts in the width direction, the edge part (one side) and the central part are exposed, and the other parts are shielded. The order and area of the exposed portions are not limited to the illustrated example. A rectifier 7 applies a positive potential to the loaded divided anode 31 via the divided anode table 32. In this way, by making the masking range of each divided anode adjustable, the amount of plating adhesion can be adjusted, and it can be made uniform in the width direction.

Preferably, the distance between each divided anode and the metal strip is independently adjusted to adjust the amount of plating. This is because the distance between the divided anode table 32 of each divided anode and the metal strip can be adjusted by a table elevating device 34 or the like. Further, each of the divided anodes has a mask capable of independently adjusting the above-described masking range, and further has an elevating device capable of independently adjusting the distance between the metal strips, so that the width of the plating adhesion amount can be increased. The direction uniformity can be adjusted more effectively.

In an actual continuous plating facility, it is not necessary to apply the above-mentioned soluble anode to all the plating tanks. Usually, the soluble anode of the present invention is applied to any one of the plating tanks for the front and back surfaces. It only needs to be applied.
This is because the amount of excess plating to be controlled is as small as at most several weight%, and the processing capacity in one plating tank is sufficient. However, it goes without saying that the soluble anode of the present invention may be applied to a required number of plating baths in order to ensure the quality.

A new divided anode can be placed on a divided anode table, and can be sequentially arranged by an operator manually or automatically using a robot arm or the like. FIG. 2 is a schematic diagram of a continuous plating facility 2 to which the above-described soluble anode 30 of the present invention is applied. In FIG. 2, the soluble anode 30 of the present invention was applied to a 3i plating tank and a 4i plating tank (the last plating tank of the front and back surface treatment, respectively).
However, the present invention is not limited to this, and may be applied to any other plating tank (for example, 3a and 4a, 3e and 4e, etc.).

The divided anode of the soluble anode 30 of the present invention is connected to a plating adhesion amount controller 8 for individually adjusting the distance between the anode and the metal strip based on the measurement data from the plating adhesion meter 6. Is done. Normally, as already described, since the plating thickness becomes thinner at the center in the width direction of the metal strip and becomes thicker at both ends, the soluble anode 30 of the present invention includes:
The divided anode table at a position where there is no masking at the center is adjusted so as to approach the direction of the metal strip, and the other divided anode tables are lowered away from the metal strip. However, it is natural that various patterns are used according to the operation situation.

This adjustment is made based on the measurement data of the plating adhesion meter 6 so that the plating is uniform in the width direction, and it is easy to apply a known control method or the like. Note that the present invention relates to a plating method and apparatus based on anode supply using a bar-shaped split anode, but is shown in FIG. 1C instead of the split anode 31 in FIG. Split anode divided into multiple parts in the width direction of the metal strip
31 may be applied. Further, the divided anode table 32 shown in FIG.
Instead, a basket anode may be applied to uniformly supply the plating raw material in the form of a pellet (for example, tin pellets) in the width direction of the metal strip.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is an ETL (Electric Tin Plating Equipment) that tinplates a steel plate as a tinplate and produces tinplate.
Applied to In the soluble anode of the present invention, FIG. 1C is installed in the plating tanks 3i and 4i shown in FIG. The tinplate to be applied is an ultra-low-carbon or low-carbon steel strip having a thickness of 0.12 to 0.45 mm and a width of 560 to 1020 mm. Plating equipment speed is 10
0 to 420 mpm, and the coating weight is 0.5 to 15 g / m ^2.
Range.

The monthly tin production of this facility is 26,000 tons.
And the average amount of tin deposited is 3 g / m ^TwoIt is. here,
Conventionally, as shown in FIG. 5, a central portion (C
e) In order to guarantee plating adhesion in (e), both ends (Op,
Dr), the amount of adhesion was excessive.
By the light, the amount of adhesion is made uniform, and both ends (Op,
Dr) can be reduced, and the total amount is doubled.
The amount was reduced by%. This is about 2 in tin equivalent.
 Equivalent to ton / month reduction.

[0027]

According to the present invention, the amount of tin in the ETL can be reduced by about 2 ton / month, and the amount of tin used in the plating process can be increased only by mechanically simple equipment modification and a change in anode specifications. It was possible to reduce the cost of equipment.

[Brief description of the drawings]

FIG. 1 is a plan view (a) and a side view (b) of a soluble anode of the present invention, and a plan view (c) of another embodiment of the present invention.

FIG. 2 is a schematic diagram of a continuous plating facility to which the present invention is applied.

3 (a) is a plan view and FIG. 3 (b) is a side view of a conventional soluble anode.

FIG. 4 is a schematic view of a conventional continuous plating facility.

FIG. 5 is a graph of a plating weight distribution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal strip (plated tinplate) 2 Continuous plating equipment 3a-3i, 4a-4i Plating tank 5 Roll 6 Plating weight meter 7 Rectifier 8 Plating weight adjusting device 20 (Conventional) soluble anode 21 (Conventional) anode 22 (Conventional) main anode 30 (inventive) soluble anode 31 (in accordance with the invention) split anode 32 split anode table 33 mask 34 split anode table lift

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshihiko Chino 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Chiba Works of Kawasaki Steel Corporation (72) Inventor Fumio Aoki 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki 4K024 AA07 AB01 BA03 BC01 CA16 CB08 CB09 CB21 EA02 GA16

Claims (6)

[Claims] 1. A plating method for a metal strip using a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal strip, and a masking range of each of the divided anodes is adjusted. A method for plating a metal strip, comprising: 2. A method for plating a metal strip using a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in the longitudinal direction of the metal strip, and the distance between each of the divided anodes and the metal strip is adjusted. A method for plating a metal strip, comprising adjusting the amount of adhesion. 3. A method for plating a metal strip using a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal strip, and a masking range of each of the divided anodes is adjusted. A method for plating a metal band, wherein the distance between the divided anode and the metal band is independently adjusted to adjust the amount of plating. 4. In a metal strip plating apparatus provided with a soluble anode, the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal band, and each of the divided anodes can adjust a masking range. A plating apparatus for a metal strip, comprising a mask. 5. A plating apparatus for a metal strip provided with a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal strip, and each of the divided anodes has an independent distance from the metal strip. A plating apparatus for a metal strip, comprising: an elevating device that can be adjusted. 6. A plating apparatus for a metal band provided with a soluble anode, wherein the soluble anode is divided into a plurality of divided anodes in a longitudinal direction of the metal band, and each of the divided anodes can adjust a masking range. A plating apparatus for a metal strip, comprising a mask, and further comprising an elevating / lowering device that allows each of the divided anodes to independently adjust a distance from the metal strip.