JP2901488B2 - Continuous electrolytic treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to EGL (Electro Galvanizing Line), ETL (Electric Tin Plating Line),
Prevents current concentration on the edge of the metal strip to be processed in a horizontal continuous electrolytic processing apparatus such as an electroplating processing apparatus in each line such as a TFL (tin-free line).
The present invention relates to a continuous electrolytic treatment method , and particularly to a continuous electrolytic treatment method for preventing edge overcoating in a plating apparatus.

[0002]

2. Description of the Related Art A case where a steel sheet is continuously electroplated will be described as an example. An extreme current is concentrated on an end portion of a metal strip (hereinafter referred to as a steel plate), and an overcoat is not covered at the end portion. In order to prevent such overcoating, see JP-A-52-1.
As disclosed in Japanese Patent No. 30435, a method of inserting an insulator called an edge mask between a steel plate and an anode so as to wrap the vicinity of the steel plate edge with a gap to prevent current from concentrating on the steel plate edge is known. Has been taken.

[0003]

As shown in FIGS. 2 and 3, a conventional edge mask for preventing an edge overcoat generally has a U-shaped or a U-shaped cross section.
The edge overcoat has been prevented by pushing the end of the steel plate inward from both ends of these edge mask openings by a predetermined distance. The feature of these edge masks is that they are used with the end of the steel plate pressed into the inside of the edge mask.Therefore, considering the poor shape of the steel plate, warpage in the width direction and vibration of the plate, etc. The distance (dimension a in FIG. 4) is increased, and accordingly, the thickness b of the mask material and the gap c between the edge mask 1 and the anode 3 are reduced. Note that d is the distance between the upper and lower electrodes, and is usually d = a + 2b +
2c.

On the other hand, in recent years, the distance between the anode 3 and the steel plate 2 has tended to be shortened in order to reduce the power consumption unit (currently,
9-15 mm is the mainstream), and there are limits to reducing the thickness b of the mask material due to problems in strength and processing.
There is a limit in reducing the gap c between the mask opening and the anode 3 due to operational problems, so that the distance a between both ends of the mask opening has to be reduced. Accordingly, since the steel plate is used while being pressed into the inside of the edge mask, there is a high possibility that the steel plate may further come into contact with the edge mask if there is a shape defect of the steel plate, warpage in the width direction, or vibration of the plate.

[0005] Even when a flat steel plate is passed through, an edge mask having a large distance a between both ends of the mask opening and a small thickness b of the mask material has a large current wraparound, so that edge overcoating is not possible. In order to prevent this, it is necessary to increase the pushing distance of the steel plate. When the pushing distance of the steel sheet is increased, overcoating of the edge portion can be prevented, but the portion slightly inside the edge becomes an undercoat, and the distribution of the amount of adhesion in the width direction of the plate becomes non-uniform, for example, as shown in FIG.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce current concentration on the edge of a steel sheet, to prevent overcoating on the edge of a steel sheet in the case of plating, and to improve the shape of the steel sheet, warp in the width direction, and vibration of the sheet. can Ru continuous electrolytic treatment of the like is steel even to minimize possibility of contact with the edge mask
Is to propose a method .

[0007]

SUMMARY OF THE INVENTION The present invention relates to a continuous electrolytic process using an edge mask for preventing current concentration on an edge portion of a metal strip to be processed in a horizontal continuous electrolytic process apparatus.
In the method , the cross-sectional shape is U-shaped, U-shaped, or an intermediate shape thereof, the distance a between both ends of the mask opening is set to 1/3 or less of the distance d between the upper and lower electrodes , and the thickness of the mask material at the opening is set. d is taken as 1/10 or more b vertical distance between electrodes d
Use an edge mask to cut the edge of the opening of the edge mask
Is a continuous electrolytic process how to and performing installed electrolytic treatment so that the outside of the di portion.

In the present invention , the cross-sectional shape of the edge mask according to the present invention is described as a U-shape or a U-shape. included.

[0009]

According to the present invention, the distance a between the two ends of the opening of the edge mask is set to be not more than 1/3 of the distance d between the upper and lower electrodes.
As shown in (a), the current density at the steel plate end is smoothed as compared with the conventional current density at the steel plate end shown in FIG. 5 (b), and overcoating on the steel plate edge is prevented. it is conceivable that. Therefore, in the present invention, it is desirable to further reduce the distance a between both ends of the opening of the edge mask, and it can be set to 1/10 or less of the distance d between the upper and lower electrodes, but the lower limit is at least the thickness of the treated steel sheet. It is desirably three times or more. This is because the end of the steel plate does not contact the edge even if the width of the plate fluctuates and the plate vibrates.

The inventor of the present invention has set the distance a between both ends of the opening of the edge mask to be not more than １ ／ of the distance d between the upper and lower electrodes, and as shown in FIGS. When the thickness b of the material is changed, the edge of the opening of the edge mask is installed at a distance outside the edge of the steel plate as shown in FIG. 7, that is, even if the distance of e shown in FIG. It has been found that edge overcoat can be prevented.

For example, assuming that the distance a between both ends of the opening of the edge mask is 1/3 of the distance d between the upper and lower electrodes, a limit value at which the tip of the edge mask can be separated from the edge of the steel plate depending on the thickness b of the mask material. e changes as shown in FIG. In this case, when the thickness b of the mask material is 1/10 of the distance d between the upper and lower electrodes, the limit value e at which the tip of the edge mask can be separated from the edge portion of the steel plate is 1/6 of the distance d between the upper and lower electrodes. When the thickness b of the mask material is 1/4 of the distance d between the upper and lower electrodes, the limit value e at which the tip of the edge mask can be separated from the edge of the steel plate is 1/3 of the distance d between the upper and lower electrodes. In the present invention,
Mask material thickness b from the results shown in FIG. 7 is 1/10 or more top and bottom electrode distance d is desirable.

As a result, the number of times of contact between the steel plate 2 and the edge mask 1 was reduced, the defect rate of the product due to the flaw of the edge portion was reduced, and the life of the edge mask 1 was prolonged. Further, as shown in FIG. 8, the uniformity of the distribution of the attached amount is much improved as compared with the conventional edge mask (see FIG. 9). As a result, the target adhesion amount can be suppressed to a small value, and the basic unit of the plated metal can be improved.

The width (f shown in FIG. 1) of the edge mask 1 in the present invention is not particularly limited, but is preferably at least 1/2 of the distance d between the upper and lower electrodes from the viewpoint of strength and handling.

[0014]

FIG. 1B shows an embodiment and FIG. 2 shows a conventional example.
1m using the edge mask of electrogalvanizing equipment shown in
Table 1 and FIG. 8 (Example) and FIG. 9 (Conventional Example) show the specifications and results when galvanizing the width steel sheet with a target basis weight of 50 g / m ² . Here, the edge overcoat ratio is (zinc adhesion amount at steel sheet edge / zinc adhesion amount at steel sheet central part) × 100 (%).

[0015]

[Table 1]

According to the present invention, the amount of plating applied to the end of the metal strip can be smoothed, and the defect rate of products caused by flaws caused by contact of the edge can be effectively reduced.

[0017]

As described above, according to the present invention, it is possible to prevent overcoating of the end portion of the steel plate even if it is installed at a position outside the end portion of the edge mask and the end portion of the steel plate. The amount of plating in the direction could be smoothed. For this reason, the plating target adhesion amount could be suppressed to a small value, and the trimming amount was reduced, so that the basic unit of the plating metal could be improved. In addition, there has been a remarkable improvement in the product failure rate due to flaws caused by contact with the edge portion and an improvement in the life of the edge mask.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the vicinity of an edge mask portion of a horizontal continuous electrolytic processing apparatus according to the present invention.

FIG. 2 is a sectional view showing the vicinity of an edge mask portion of a conventional horizontal continuous electrolytic processing apparatus.

FIG. 3 is a cross-sectional view of the vicinity of an edge mask portion of a conventional horizontal continuous electrolytic processing apparatus.

FIG. 4 is an explanatory view showing a definition of dimensions of each part of an edge mask portion of the horizontal continuous electrolytic processing apparatus.

FIG. 5 is an explanatory diagram showing a current flow in the vicinity of an edge mask portion of the horizontal continuous electrolytic processing apparatus.

FIG. 6 is a cross-sectional view showing the vicinity of an edge mask portion of the horizontal continuous electrolytic processing apparatus according to the present invention, and is a cross-sectional view showing a change in mask material thickness.

FIG. 7 is a graph showing a relationship between a mask material thickness b and a limit value e at which a tip of an edge mask can be separated from an edge portion of a steel plate.

FIG. 8 is a graph showing a relationship between a distance from a steel sheet edge and an edge overcoat ratio when the present invention is implemented.

FIG. 9 is a graph showing a relationship between a distance from a steel sheet edge and an edge overcoat ratio in a conventional case.

[Explanation of symbols]

 1 Edge mask 2 Steel plate 3 Electrode a Distance between both ends of mask opening (dimensions) b Mask material thickness c Distance between edge mask and anode (dimensions) d Distance between upper and lower electrodes (dimensions)

Claims (1)

(57) [Claims] 1. A continuous electrolytic processing method using an edge mask for preventing current concentration on an edge portion of a metal strip to be processed in a horizontal continuous electrolytic processing apparatus, wherein a cross-sectional shape of the continuous electrolytic processing apparatus is U-shaped or square-shaped. And the distance between the two ends of the mask opening (a) is the distance between the upper and lower electrodes (d).
And the mask material thickness (b) of the opening is
Edge mass that is 1/10 or more of the distance (d) between the upper and lower electrodes
Edge of the opening of the edge mask from the steel plate edge
It is characterized by being installed outside and performing electrolytic treatment
Continuous electrolytic processing how.