KR100506387B1 - Method for double electro-plating a strip - Google Patents

Abstract

The present invention performs the plating of more than 60% in the radial plating apparatus using the electroplating device of the positive electrode and the negative electrode, and then performs the plating in the vertical or horizontal plating apparatus sequentially the remaining plating amount on the plating layer again, in the latter apparatus It is a double electroplating method which improves the quality by plating at least 2g / m ² or more and removing the surface appearance of the plating layer and traces of the contact surface of the conductive steel and improving the productivity by performing high-speed electroplating. The surface appearance of the strip plating layer is good. This improves the quality and enables high current density plating to improve productivity.

Description

Method for double electro-plating a strip

The present invention relates to a dual electroplating method that can satisfy the surface quality and productivity improvement of the electroplating material at the time of the continuous electroplating, in particular by connecting the plating device of the radial form and the vertical or horizontal form sequentially The present invention relates to a dual electroplating method capable of improving the surface appearance of an electroplating material and capable of high current density plating.

In general, plating is performed to improve corrosion resistance of steel sheets, and electroplated steel sheets, which are plated by electric force, are widely used in fields such as home appliances, automobiles, and construction. On the other hand, since the thickness of the zinc plated layer should be increased in order to ensure corrosion resistance in a harsh atmosphere, it is necessary to increase the productivity by plating at high speed in order to reduce the cost. To this end, various electroplating apparatuses have been developed in different countries, adopting different electroplating methods.

Such conventional electroplating apparatuses are largely classified into three types. That is, the radial type electroplating apparatus (see FIG. 1) disclosed in Japanese Patent Nos. 58113398 and 54074224, European Patent No. 905228, and the like, and the vertical type disclosed in European Patent Nos. 904188 and 90301. Electroplating apparatus (see FIG. 2), horizontal type electroplating apparatus (see FIG. 3) disclosed in European Patent No. 242966 and the like. And, these electroplating devices all have their advantages and disadvantages.

That is, the radial type electroplating apparatus is easy to single-side plating, the productivity of the plating material is higher than other types of apparatus, but the surface appearance is not good. In addition, where the conductive steel strip and the plated surface of the conductive roll are in contact with each other, there is a drawback that a trace occurs on the surface when zinc, tin plating, or the like having low hardness is performed. The vertical type electroplating apparatus has a problem in that the surface appearance is good because there is no contact with the conductive roll during plating, but the plating cell is complicated and high speed mailing is difficult due to high current. In addition, the horizontal plating apparatus has the advantage that the surface appearance is good because there is no contact with the roll in the place where plating is performed, and unlike the radial type electroplating apparatus, there is no trace on the surface of the plating layer by conduction. Single-sided plating is difficult, it is difficult to maintain a uniform gap between the positive electrode and the negative electrode during plating, the quality defects are caused by the deflection phenomenon, thereby reducing the productivity.

Therefore, in order to improve the conventional problems as described above, the present invention is to provide a dual electroplating method that can be applied to each advantage by sequentially arranging the radial type plating apparatus and the vertical or horizontal plating apparatus in sequence. Its purpose is to.

In addition, the object of the present invention is to perform the most of the target plating amount to be performed on the steel plate in the radial type electroplating apparatus, and then to increase the productivity of electroplating by plating the surface of the plating layer in a vertical or horizontal electroplating apparatus In addition, the present invention provides a dual electroplating method capable of producing an electroplated steel sheet having a good surface appearance.

In order to achieve the object as described above, the dual electroplating method according to the present invention for plating both sides of the steel sheet is a pre-plating step for one-side plating of about 60% of the target plating amount, and both sides of the one-side plated steel sheet At the same time characterized in that the plating consisting of a finishing plating step.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the dual electroplating method according to the present invention, after one side of the strip is plated at about 60% of the target plating amount, both sides of the strip are simultaneously plated.

First, one side of the strip is plated using the radial type electroplating apparatus shown in FIG. That is, the radial type electroplating apparatus is plated on one side of the strip by using the advantage that the current efficiency is good at the beginning and high current can be injected.

For example, referring to FIG. 1, the pretreated strip 1 is drawn into a radial electroplating apparatus and plated. At this time, between the positive electrode 4 which is immersed in the plating bath and the strip whose one surface is in contact with the conductive roll 3, the positive electrode 4 is maintained at 5 to 50 mm when the positive electrode 4 is soluble.

However, the spacing between them should be as narrow as possible. That is, if the interval between them is too wide, the current efficiency decreases during high current density operation, and if the interval is 5 mm or less, the plating layer in which the anode 4 and the strip 1 are burned in contact with each other is burned. Is formed on the strip surface.

On the other hand, in the radial electroplating apparatus, when the strip is drawn into the plating bath, the plating amount can be increased by attaching a contact roll and applying a high current. Therefore, in this radial plating bath, at least 60% or more of the total target plating amount should be plated on one side of the strip, and as much as possible, the plating steel sheet productivity is improved.

Thereafter, as described above, the strip plated in one side of the radial electroplating apparatus is charged into the vertical or horizontal electroplating apparatus shown in FIG. 2 or 3, irrespective of the single / duplex plating material of the strip. And double-sided plating is performed.

On the other hand, referring to Figure 2, when the one-sided strip 1 is sprayed with water before passing through the inlet roll 2, the state of the double-sided plating performed in the vertical electroplating apparatus is good. Then, both sides of the strip drawn into the plating bath of the vertical electroplating apparatus are plated while passing between a pair of anodes in the plating bath, and the plating amount performed at this time is preferably about 2-30 g / m ² . This is because if the plating amount is less than ² g / m ² , the surface appearance and surface traces of the plated strip cannot be removed by the radial electroplating apparatus. In addition, when the plating amount of the strip surface exceeds 30g / m ² , because the plating speed depends on the plating state, high current plating is impossible.

However, according to a preferred embodiment of the present invention, it is preferable that the plating amount of both sides of the strip performed in the vertical electroplating apparatus is about 5-10 g / m ² .

As described above, although the surface of the strip was plated using two different types of plating apparatuses, a good plating layer and a productivity improvement could be obtained. However, such a plating effect may be achieved by forming a plating layer of the same metal on the surface of the strip, Even when the plating layers of the above different metals are formed, a plating layer with good plating quality and an improvement in productivity can be obtained.

<Example>

Surface appearance (stripes and surface contamination), surface traces (conduction roll marks), and current of the coating layer when the zinc plating amount is 40 g / m ² according to the plating conditions in the plating solution composition shown in Table 1 below using the cold rolled steel sheet as the base metal. Density is the same as productivity.

On the other hand, the plating solution of Table 1 as a zinc plating bath of chloride in the case of a radial plating bath, it was adjusted to zinc: 100g / L, chlorine: 250g / L, pH = 4, temperature = 60 ℃. However, in the vertical and horizontal electroplating apparatuses for carrying out the double electroplating method according to the present invention, the same plating solution was used as in the radial plating bath, and zinc: 120 g / L and sulfide: The plating bath which maintained the temperature of 70 degreeC in the plating liquid which is 240 g / L, and consisted of sodium sulfate 35g / L was used.

Number Radial Plating Equipment Vertical / Horizontal Plating Equipment Plating bath type Plating amount Surface appearance Surface groove High Current Density Plating Radial Vertical / horizontal One use unused Hydrochloric acid bath 40 0 X X O 2 use use Hydrochloric acid bath 39 One X X O 3 use use Hydrochloric acid bath 38 2 O O O 4 use use Hydrochloric acid bath 35 5 O O O 5 use use Hydrochloric acid bath 30 10 O O O 6 use use Hydrochloric acid bath 25 15 O O O 7 use use Hydrochloric acid bath 20 20 O O X 8 use use Sulfuric acid bath 39 One X X O 9 use use Sulfuric acid bath 38 2 O O O 10 use use Sulfuric acid bath 35 5 O O O 11 use use Sulfuric acid bath 30 10 O O O 12 use use Sulfuric acid bath 25 15 O O O 13 use use Sulfuric acid bath 20 20 O O X

As shown in Table 1, the surface appearance of the plating layer is good under the conditions consistent with the present invention, there is no surface flaw, and high current density plating is possible, but it is poor in the plating conditions outside the scope of the invention.

In other words, in the method of plating the strip continuously consisting of a plating solution, a positive electrode and a negative electrode, initial plating is performed by using a plating cell in the form of a radical, followed by plating by a plating cell in a vertical or horizontal manner. The plating amount of the form is to be 60% or more of the total plating amount, and the minimum amount to be plated in the vertical or horizontal type is to be 2g / m ² or more.

When the strip to be plated by the plating method as described above is plated in a vertical or horizontal plating apparatus, the plating amount is about 2-30 g / m ² , wherein the plated products are phosphate treated, chrome treated, resin Post-treatment such as treatment.

As described above, according to the present invention, the electroplating apparatus capable of continuously electroplating the strip is first plated continuously with a device in the form of a radial to ensure an appropriate plating amount on one side of the strip, and then vertical or horizontal electroplating. By plating both sides of the strip with a plating apparatus, the surface appearance of the strip plating layer can be improved to improve quality, and high current density plating can be performed to improve productivity.

The foregoing is merely illustrative of the preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. It should be recognized.

1 is a radial (carousel) type electroplating apparatus.

2 is a vertical electroplating apparatus.

3 is a horizontal electroplating apparatus.

<Description of Symbols for Major Parts of Drawings>

1: continuous steel strip

2: incoming steel support roll

3: discharge steel strip support roll

4: anode

Claims (4)

delete In the double electroplating method consisting of a plating solution and a positive electrode and a negative electrode to continuously plate both sides of the strip, A pre-plating step of plating one side of the strip to at least 60% of a target plating amount with a radical plating apparatus; Double-plating electroplating method characterized in that the one-side plating and both sides of the strip of water is made of a plating finish at the same time the plating amount by ² ~ 30g / m ² by a vertical electroplating device. The method of claim 2, wherein both sides of the strip are sequentially single-sided plating in the pre-plating step. The method of claim 3, wherein the plating solution of the plating bath used in the pre-plating step and the finish plating step is made of the same solution.