JPH06158386A - Electroplating method for steel sheet that prevents edge overcoat - Google Patents

Abstract

PURPOSE:To prevent edge overcoating and to reduce the trimming amt. at the time of continuously electroplating the surface of a steel sheet by previously covering the side face of the sheet with a plating preventive insulating coating material. CONSTITUTION:When the surface of a steel sheet 2 is continuously electroplated, a plating preventive insulating coating material 10 is applied on the side face 9 of a coil 8 with a brush 11. Otherwise, the sheet 2 is continuously conveyed in direction of the arrow 17, a coating material 12 is supplied to a spray nozzle 14 by a pump 13 and sprayed over a transfer roll 15, the film thickness of the coating material 12 is adjusted by the pressures of the transfer roll 15 and coater roll 16, and the coating material 12 is applied on the end face of the sheet 2 by the coater roll 16. Consequently, the overcoating of the end face is surely prevented, and the part is not plated in accordance with trimming margin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to steel sheet EGL (electrogalvanized line), ETL (electrotin plated line), T
The present invention relates to an electroplating method in each line such as FL (tin free line), and particularly to prevention of edge over coating.

[0002]

2. Description of the Related Art When a steel sheet is continuously electroplated, a pole current concentrates on the edge of the steel sheet, and an overcoat cannot be applied to the edge. In order to prevent such an overcoat, an overcoat protector is widely used.

[0003]

A conventional edge overcoat protector is a non-contact type with a steel plate end, and a typical sectional view thereof is shown in FIG. The steel plate 2 passes through the plating tank 1 and the electrodes 3 are arranged on one or both surfaces of the steel plate 2.
The width of the electrode 3 is wider than the width of the steel plate 2 because the width of the steel plate 2 usually changes. In such a state, the pole portion current is concentrated by the end portion of the steel plate 2 and overcoating occurs. As a countermeasure against this, a protector 5 which is movable in the arrow direction 4 according to the width of the steel plate 2 is provided, and the end of the steel plate is shielded from the electrode 3 to eliminate overcoating. However, since the protector 5 is not in contact with the steel plate 2, more reliable overcoating cannot be performed, resulting in waste of the amount of metal to be plated and waste of cutting the plated steel plate end portion by 5 to 10 mm.

An object of the present invention is to propose a method for electroplating a steel sheet which prevents edge overcoating and which can further save the plating metal and reduce the trimming amount.

[0005]

According to the present invention, when the surface of a steel sheet is continuously electroplated, the steel sheet side end surface portion is previously coated with an anti-plating insulating paint, or the steel sheet is pre-plated. It is a method of electroplating a steel sheet that prevents edge over coating, which is characterized by coating the area to be trimmed at the end with an insulating paint for plating prevention.
As a method for coating the paint, a method of rewinding the coil and pressing a coater roll on the end portion of the steel plate during continuous transportation to apply an insulating paint for preventing plating can be advantageously used.

[0006]

In the method of preventing edge overcoating of the present invention, the paint 10 is brushed off as shown in the overall coil view of FIG.
Coating the side surface 9 of the coil 8 or the steel plate 2 is continuously conveyed in the direction of the arrow 17 as shown in the overall view of the coil end coating apparatus of FIG. 16 to feed the paint 12 by the pump 13, spray from the spray nozzle 14, adjust the film thickness of the paint 12 by the pressing force of the transfer roll 15 and the coater roll 16, and apply the paint 12 to the end surface of the steel plate 2. Not only can it be applied, but the paint can also be applied to the steel plate surface side. Of course, other methods can be adopted.

The steel sheet 2 whose end surface is coated with the insulating paint by such a method is not electroplated in the plating tank 1. Therefore, the overcoating of the end portion can be surely prevented, and the portion can be unplated according to the trimming allowance, so that the trimming amount can be reduced while saving the plating metal.

[0008]

EXAMPLE In Example 1, the paint 10 was applied by the brush 11 to the coil end surface 9 by the method shown in FIG. As the coating material 10, an insulating coating material for preventing plating, Melcoat manufactured by Woshin Chemical Industry Co., Ltd. and Sabicon manufactured by Showa Yuken Co., Ltd. were used. As a result of rewinding and electroplating the coil 8 as shown in FIG. 3, it was possible to reliably obtain a plating deposition amount of 0 on the end surface of the steel plate as shown by the black circle line 7 in the plating deposition amount.

As a comparative example, the protector shown in FIG. 4 is used, and the set weight is 5 g on the electric tin plating line.
/ M ² and was the coating weight of the steel plate 2 in FIG. 3 shown by a white circle line 6. When the conventional non-contact protector 5 is used, the actually measured value of the adhesion amount is twice or more the setting amount at the plate end as shown by the white circle line 6, and the trimming width must be large. Absent.

As the second embodiment, the trimming width was set to 6 mm using the coater roll shown in FIG. 2, and the same insulating coating material as that of the first embodiment was applied to the width of about 3 mm from the plate end. The amount of coating adhered to the steel plate 2 when the set weight is 5 g / m ² is shown by a Δ line 7 ′ in FIG. The amount of plating adhered within a width of 3 mm from the plate edge was 0, and unnecessary plating was substantially omitted.

The paint applied to the end surface of the steel plate can be easily removed by an end surface brush roll in the post-process of electroplating. In the case of trimming after plating, it is not necessary to remove the paint because it will be scrapped off.

[0012]

As described above, according to the present invention, in addition to ensuring that the amount of coating adhered to the outermost end surface of the steel plate is 0, the range where the paint adheres to the central portion of the steel plate several mm from the end is the amount of coating adherence. Could be reduced. Therefore, it is possible to prevent waste of the coating amount and reduce the trimming amount.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a coating method of a coil end surface according to the present invention.

FIG. 2 is an explanatory view showing a coating method of an end surface of a steel plate according to the present invention.

FIG. 3 is a graph showing a change in a weight per unit area of a steel plate.

FIG. 4 shows a typical sectional view of a conventional plating tank.

[Explanation of symbols]

 1 Electroplating bath 2 Steel plate 3 Electrode 4 Protector adjustment position 5 Protector 6 Adhesion amount by the conventional method 7 Adhesion amount by the present invention method 7'Adhesion amount by the present invention method 8 Coil 9 Side part 10 Paint 11 Brush 12 Paint 13 Pump 14 Spray Nozzle 15 Transfer roll 16 Coater roll 17 Transport direction

Claims (3)

[Claims] 1. A method for electroplating a steel sheet which prevents edge overcoating, characterized in that when a surface of a steel sheet is continuously electroplated, an end surface portion on the steel sheet side is previously coated with an insulating paint for preventing plating. . 2. When the surface of a steel sheet is continuously electroplated, the edge overcoating is characterized in that the area to be trimmed at the edge of the steel sheet is previously coated with an insulating paint for preventing plating after plating. Method for galvanized steel sheet. 3. A steel sheet with edge-over coating prevented according to claim 1 or 2, wherein the coil is rewound, and a coater roll is pressed against an end of the steel sheet during continuous conveyance to apply an insulating coating for preventing plating. Electroplating method.