JP2712118B2 - Continuous electrolytic treatment of steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuous electrolytic treatment of a steel strip in which a plating solution flows into a gap between an electrode and a steel plate placed in parallel with a steel plate interposed therebetween to perform electroplating or the like.

[0002]

2. Description of the Related Art Electroplating by flowing a plating solution into a gap between an electrode and a steel plate placed in parallel with a steel plate interposed therebetween is roughly classified into (1) a horizontal jet system and (2) a vertical jet system. There is.

In these systems, (1) it is difficult to make the flow velocity distribution uniform in the width direction of the sheet, and it is not possible to ensure uniform characteristics of the plating layer. (2) If the line speed increases, it becomes difficult to fill the gap between the electrode and the steel sheet with the plating solution, and a gas phase is involved, and a pinhole or the like occurs in plating. And so on.

To solve such problems, (1) Japanese Patent Publication No. 4-9876 discloses a method of filling a gap between an electrode and a steel sheet with a plating solution in a vertical jet type electroplating method. A seal mechanism (including a seal liquid storage section and a liquid seal throat section) for sealing a gap between a nozzle and an upper portion of an electrode with a plating solution is disclosed.

[0005]

On the other hand, in a horizontal jet type electroplating method in which a plating solution flows into a gap between an electrode and a steel plate placed in parallel with a steel plate interposed therebetween, when the line speed increases, the It is difficult to fill the gap between the steel and the steel plate with the plating solution, and there is a problem that the gas phase is entrained from the outside and pinholes of the plating occur, and the current density becomes uneven and the plating layer becomes uneven. Was.

[0006] In addition, in the method provided with a sealing mechanism such as a seal roll, the equipment becomes complicated, and the problem of maintenance is left. SUMMARY OF THE INVENTION An object of the present invention is to provide a continuous electrolytic treatment method for a steel strip which has small and simple equipment which solves the above-mentioned problems, improves plating quality, and can be applied to a high-speed line.

[0007]

According to the present invention, there is provided an electrode parallel to the upper and lower sides of a steel strip, and side walls at both side ends of the electrode.
Each of the upper and lower electrodes has a supply port for a plating solution, and the inlet and outlet of the steel strip are connected to the steel plate and the electrode using a horizontal jet type plating apparatus having a tunnel structure that is open to the air. When plating while filling the gap with plating solution,
The steel strip and the plating apparatus are inclined with respect to the horizontal plane so that the steel strip exit side is above the steel strip entrance side, and the installation angle θ of the steel strip and the plating apparatus with respect to the horizontal plane is determined by the passing speed of the steel strip. A continuous electrolytic treatment method for a steel strip characterized by increasing or decreasing in accordance with the increase or decrease in the thickness, respectively, to prevent air bubbles from entering the plating apparatus.

[0008]

The present inventors have clarified that the invasion of the external gas phase carried by the steel plate can be prevented by returning the plating solution to the inlet side. It was revealed that the amount of return increased with increasing line speed.

Therefore, in the present invention, by inclining the steel plate and the electrode at a certain angle corresponding to the line speed, the amount of the plating solution required to fill the plating solution up to the electrode exit side and the plating solution necessary to prevent the intrusion of external air are reduced. The return amount can be secured without excess or shortage. As a result, even if the steel plate and the electrode are installed at an appropriate angle even in the high-speed region with a line speed of 400 mpm or more, the gap between the steel plate and the electrode is filled with the plating solution and the intrusion of air can be prevented. Electrolysis treatment became possible.

[0010] Further, since there is no complicated sealing mechanism, the maintainability is good, and the flow of the plating solution does not hinder the stable passing of the steel sheet because the air is released before and after the electrode. FIG.
1 is a schematic view of an electrode section of a horizontal jet electroplating apparatus to which the present invention is applied. The steel plate 1 is caused to run at a speed of V ₁ between the electrodes 3 and 4 installed in parallel above and below the steel plate 1, and the plating solution is supplied from the plating solution supply header 2 to the pair of electrodes 3 and 4. The plating is supplied between the steel plate 1 and each of the electrodes 3 and 4 so that the plating solution is filled, and the plating is performed by energizing the steel plate 1 and each of the electrodes 3 and 4. Reference numeral 5 denotes a side wall for sealing between the electrodes in a tunnel shape.

At this time, when the line speed V ₁ increases, FIG.
As shown in FIG. 2A, the plating solution is not filled because the steel sheet 1 entrains the gas phase from the outside, or as shown in FIG. Such a problem arises. The present invention addresses these problems as follows. (1) External air phase entanglement preventing external gas phase winding is prevented by the return amount to Q ₁ to the electrode inlet direction of the plating solution shown in FIG. 3 (b). You need to worry about phase entanglement preventing Q ₁ is increased with the line speed increase.
(See FIG. 4). (2) the flow rate Q ₃ shown in FIG. 3 (c) of the electrode outlet cavity preventing the steel sheet 1 begins to carry increases the line speed increases and accompanied. Therefore it is necessary to secure the Q _3.

The header supply amount for securing Q ₁ is Q
_Assuming that the header supply amount Q _0.3 for securing _0.1 and Q ₃ , each has a relationship as shown in FIG. 4 depending on the line speed. Therefore, the header supply amount Q ₀ satisfying Q ₁ and Q ₃ is as shown in FIG. At this time, the Q ₃ to satisfy Q _0.1 becomes excessive in the region of II becomes excessive Q ₁ in order to satisfy Q _0.3 in the area of I. At point A where Q _0.3 and Q _0.1 intersect, both Q ₁ and Q ₃ are satisfied without excess and deficiency. Therefore, at any line speed, Q ₁ ,
The Q ₃ are to satisfy just proportion set the installation angle θ FIGS. 3 (a) to the electrodes 3, 4 and the steel plate 1 according to the line speed as shown, when well-balanced distribution of Q _1, Q ₃ good.

[0013] For example Q ₀ is just enough Q ₁ at minimum to theta = 15 ° as jet angle α is shown in FIG. 5, line speed 800mpm when 30 degrees Q ₀ from the header 2 to the steel plate 1, Q ₃ To be satisfied. FIG. 6 shows an example of the relationship between the proper installation angle θ and the line speed V ₁ when α = 30 degrees. In actual operation, if the installation angle is set at the maximum line speed, it is easy to control Q ₀ at a line speed lower than that. However, it is necessary to consider the influence of the distance between the poles, the jet angle of the header, the width of the steel plate, the width of the electrode, and the like for the appropriate installation angle θ.

The setting angle of the plating apparatus can be easily adjusted by providing an angle adjusting device such as a cylinder below the plating apparatus.

[0015]

【Example】

Example 1 When a chromate treatment was performed under the following conditions, a uniform coating was obtained. Opening diameter of plating equipment 1200 × 30mm Steel strip width, thickness 800 × 0.25mm Passing speed 600mpm Inclination of plating equipment and steel strip (θ) 15 ° Plating solution supply rate (Q ₀ ) 4.5m ³ / min Comparison Example Chromate treatment was performed under the same conditions as in Example 1 except that the inclination (θ) of the plating apparatus and the steel strip was set to 0 °, that is, horizontal, but bubbles were introduced and a uniform film could not be obtained.

[0016]

According to the present invention, the flow rate of the plating solution necessary for filling the gap between the steel plate and the electrode with the plating solution is supplied from the header, and the steel plate and the electrode placed in parallel with the steel plate interposed therebetween. By installing the plating solution at a predetermined angle according to the line speed, the plating solution was distributed without excess and deficiency, and the plating solution could be easily filled. Further, the plating solution can be filled, thereby making the plating layer uniform and improving the quality.

Further, in this electrolytic treatment method, since the electrode entrance and exit are open to the atmosphere, the stability of the plate is improved and the plating solution can be easily filled, so that the treatment at a high speed is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic view of the periphery of an electrode of an electroplating apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating the filling of a plating solution in a gap between a steel plate and an electrode.

FIG. 3 is a liquid balance diagram of a header supply amount, an inlet return amount, an outlet discharge amount, and the like.

FIG. 4 is a diagram showing a required flow rate for filling a plating solution according to a line speed.

FIG. 5 is a graph showing an example of an appropriate installation angle.

FIG. 6 is a graph showing an example of a relationship between a line speed and an appropriate installation angle.

[Explanation of symbols]

Reference Signs List 1 steel plate 2 plating solution supply header 3 electrode (upper) 4 electrode (lower) 5 side plate a external gas phase entrapment part b cavity α plating solution inflow angle θ electrode and steel plate installation angle V ₁ line speed Q ₀ header supply flow rate Q Q ₀ to ensure Q ₀ Q _0.3 Q ₃ for securing the flow rate Q _0.1 Q ₁ which is carried off in the return amount Q ₃ steel plate from _first electrode inlet

Claims (1)

(57) [Claims] An electrode parallel to the upper and lower sides of the steel strip, side walls on both side ends of the electrode, and a supply port for a plating solution provided on each of the upper and lower electrodes; When plating while filling the gap between the steel plate and the electrode with plating solution using a horizontal jet type plating system with a tunnel structure that is open to the air at the inlet and outlet of the band, the steel band outlet side is the steel band inlet. The steel strip and the plating apparatus are inclined with respect to the horizontal plane so as to be upward with respect to the side, and the installation angle θ of the steel strip and the plating apparatus with respect to the horizontal plane is set to increase or decrease the passing speed of the steel strip, respectively. Correspondingly, a method for continuously electrolytically treating a steel strip, wherein the method is increased or decreased to prevent air bubbles from entering the plating apparatus.