JPS5941517B2 - Electrolytic treatment method for metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for the electrolytic treatment of metal strip, such as steel strip, and is concerned with the removal of deposits from conductor roll surfaces.

In acid electrolytic galvanizing of steel strips, troubles often occur when zinc deposits, metal compounds, and other insoluble metal oxides adhere to the surface of the conductor roll during electrolytic treatment.

For example, an increase in current carrying resistance between the conductor roll and the steel strip, an increase in the voltage between the electrodes, the formation of arc spots, and an increase in the number of accidents resulting in scratches on the actual surface of electrogalvanized steel products that impair commercial value. It is in.

FIG. 1 shows the configuration of a vertical electrolytic cell.

The steel strip 1 is lower dipped into the electrolyte 2 and the roll 3
In vertical electrogalvanizing equipment, the conductor roll 4 is rotated upwardly and detached from the electrolytic solution 2, and then repeatedly immersed in the solution. However, if the conductor roll 4 is attached only to the upper part of the electrolytic cell, there is no polishing device for removing deposits such as electrodeposit and sludge on the surface of the roll 4 (hereinafter simply referred to as deposits). If one were to install it, the only mounting position would be the space S between the conductor roll 4 and the electrolyte level. Also, only a space s' exists on the side of the dipping roll 3. However, the space between them is quite narrow, and cleaning must be done from the bottom side of the roll, making it impossible to install a mechanical grinding mechanism.

Therefore, in general, when a press scratch or the like occurs on a steel strip, a cleaning jig with a grinding tool, such as a whetstone, attached to the tip of a rod is generally used in spaces S and S' in Figure 1, as shown in Figure 2. 5 is manually processed.

However, in reality, it is difficult to discover the welts that cause pressure scratches, and manual labor requires time and incomplete care, reduces product yield, and requires a great deal of labor, so a more useful method is desired. There is.

If the upper roll is a conductor roll in a vertical tank as shown in Fig. 1, most of the deposits will be sludge and foreign matter, and there will be little metal precipitation, but if the lower roll is also a conductor roll. In some cases, electrolytic deposition of metal occurs and manual removal is impossible due to the location.

In addition, in a horizontal tank, there is a known example in which a movable grinding mechanism 5'' is provided on the upper part of the conductor roll 4 as shown in FIG. The risk of damaging the surface is high and the mechanism is complex.

In particular, the present inventor invented the invention and applied for a patent (Japanese Patent Application No. 1983-
28026), it is very difficult to employ the known mechanical grinding method in the upper and lower conductor roll method. The present invention has been made with the aim of solving the above-mentioned drawbacks associated with electrolytic processing employing the conductor roll 4 of the present invention, and attempts to provide a method and apparatus for electrolytic processing of metal strips having the following features: It is something.

That is, as an invention of the method of the present invention, (1) When electrolytically treating a metal strip while supplying electricity to the metal strip by a conductor roll and making an electrolytic solution exist between the electrodes, the conductor in the non-contact area of the strip is - A direction for electrolytic treatment of metal strips, characterized in that an electrolytic solution is sprayed onto the roll surface.

Further, the invention of the apparatus includes (2) a deposit removing means in which an electrolytic solution spout is directed toward the surface of the conductor roll provided in the electrolytic treatment line in a non-contact area of the metal strip; It consists of a special electrolytic treatment equipment for metal strips.

The present invention preferably applies electrolytic treatment to the conductor roll 4 in the non-contact area of the conductor roll 4 shown in FIG. The electrolytic treatment solution used in the work or a solution with the same effective ingredient composition is supplied and sprayed from, for example, the injection nozzle 6, and deposits on the conductor roll surface are removed mainly by the chemical dissolution action of the electrolyte. This is the main point.

According to the present invention, the spray nozzle 6 as a removal device not only has a simpler structure and is more compact than the current mechanical abrasive removal device, but also can be used in places where it could not be applied up to now, such as metal strips. In addition to being able to be installed in a narrow space below the conductor roll that is placed in contact with the bottom surface (see reference numeral 6 in Figure 6), it is also possible to install the conductor roll in a narrow space below it without damaging the conductor roll surface. Since it is possible to efficiently remove ions, it is possible to carry out electrolytic treatment work continuously over a long period of time without replacing the conductor roll, which has a great practical merit.

Removal of deposits on the conductor roll surface is increased not only by the chemical dissolution effect but also by increasing the injection pressure of the electrolyte, which is used in combination with the physical effect. For deposited zinc and other sludge that has just deposited or adhered to the roll surface, a sufficient amount of electrolyte is injected at high pressure so that it can be removed in a very short time without giving any margin for overlapping adhesion. That is essential.

Furthermore, as described below, it is effective to enrich dissolved oxygen in the electrolytic solution ejected from the ejection nozzle in order to facilitate the dissolution of the metal deposited on the conductor roll surface. In other words, dissolved oxygen has the effect of smoothing the hydrogen ion ring reaction (cathode) that corresponds to the metal dissolution reaction (anode).

The method to enrich dissolved oxygen is to use air or other oxygen-containing gas,
Oxygenated air or pure oxygen, preferably 1k9/C
There is a method of enclosing the gas under a pressure higher than Til, or suctioning the above gas on the inlet side of the pump and causing fine entrapment.
By injecting and supplying oxygen-enriched electrolyte in this way,
Compared to the adhesion removal efficiency of an electrolytic solution that does not actively contain oxygen, it is possible to remove soil by a significant margin, and in this case, as described later, the adhesion removal electrolyte P.H.
If the amount is controlled to be 1.5 or less and the amount is injected and supplied, the removal efficiency will be improved. Although care should be taken to ensure that the electrolyte supply injection path to the non-contact surface of the conductor roll strip is as de-energized as possible, the presence of a small electrolytic current flow will not have a particularly detrimental effect on deposit removal. It doesn't seem to be given.

FIG. 5, FIG. 6, and FIG. 7 show an example of the present invention.

In the present invention, supplying an electrolyte to the surface of the conductor roll 4 in a non-contact state with the steel strip 1 means
This means supplying by one or more supply devices within a range covering the entire length of the roll 4 in the width direction, but in practical terms, the liquid is supplied by directing the electrolyte 2 through the injection nozzle 6 in the direction of the conductor roll 4 axis. It is desirable to use high-pressure injection. The electrolyte injection nozzle 6 can be fixedly fitted with a slit that covers the entire 4-axis direction of the conductor roll (Figures 5 and 6), or an electrolytic solution with a nozzle of a specific width range. This may be used as a liquid injection nozzle (FIG. 7) so as to be able to reciprocate in the width direction. Furthermore, if necessary, the injection nozzle may be divided into multiple parts in the direction of the steel strip, and the electrolyte injection pressure, flow rate, etc. may be controlled separately for each nozzle.

FIGS. 8 and 9 show an example of a nozzle. That is, the 8th
In the figure, a slit tube 9 is provided on a pipe 7, and a filter 18 is provided in front of the slit so that the speed of ejection from the slit is uniform in the width direction. FIG. 9 shows a structure that can be divided through a filter 18. conductor
Since there are restrictions on equipment space for removing deposits from the roll surface, it will be difficult to store the removal equipment unless it is as compact as possible.However, the electrolyte supply method adopted in the present invention, especially the injection The means of supply fully meet this expectation.

If for some reason it is difficult to supply electrolyte to the roll surface of the steel strip non-contact area of the conductor roll, at the point where the steel strip starts contacting or leaves the conductor roll, Directional supply of electrolyte is also possible. Furthermore, although it is not efficient when the grinding is performed manually using a jig provided with the injection nozzle of the present invention, it is superior to known grinding methods and is conceptually included in the present invention. Although the electrolyte is not directly supplied to the non-contact surface of the steel stop on the conductor roll surface, the electrolyte is supplied to the steel strip in the vicinity of the conductor roll. Supplying electrolyte indirectly to the non-contact part of the steel strip on the conductor roll surface by impinging on the surface
This is included in the concept of ``supplying electrolyte to the conductor roll surface of the non-contact area of the metal strip'' as referred to in the present invention.

FIG. 10 shows the application of the present invention to Japanese Patent Application No. 55-28026, which was invented and patented by the present inventors.

An electrolytic solution is supplied from the electrode pad 10 toward the metal strip 1, and electrolysis is performed. The electrolyte naturally flows down to the lower conductor roll 4 and the electrode pad 10 and the conductor.
The current flowing between the rolls 4 causes metal to precipitate and accumulate on the conductor roll surface. Electrolyte injection nozzle 6 connected to pump 1V to remove these deposits
An electrolytic solution is sprayed onto the conductor roll surface at high speed to chemically dissolve deposits attached to the conductor roll surface. At this time, as described above, it will be more effective if a gas supply port is provided before or after the pump 1' to enrich oxygen. As a method for oxygen enrichment, a method of pressurizing and dissolving high-pressure gas in a liquid tank or within a circulation system, or a method of injecting gas can also be adopted. Furthermore, it is also useful to add accelerators such as oxidizing agents, detergents, dispersions of fine particles, etc. to facilitate the removal of deposits. The injection pressure of the electrolytic solution is such that oxygen or an oxygen-containing gas such as air is included.

Regardless of whether or not it is possible, 0.11 < 9/d or more (or flow rate of 1 m/Sec or more), preferably 1 kg/CT
! It is preferable to set the flow rate to 1 or more (or a flow rate of 10 m/Sec or more). The electrolyte in the electrolytic cell or from a separate deposit removal electrolyte storage tank is supplied by a pump or other means to all conductors in the electrolytic treatment line.
It is sprayed onto the roll or the specific conductor roll required.

In the present invention, the term "electrolytic solution" is used as the liquid for removing deposits, but this term only has the meaning that it has substantially the same composition as the liquid used for the original electrolytic treatment. hand,
It is not used to refer to liquids that require electrolytic treatment.

The electrolytic solution PH to be sprayed is PHL. 5 or less, preferably PHO. A range of 5 to 1.0 is not only particularly effective for removing deposits on the conductor roll surface, but is also a practically desirable range for enabling high current density and high speed electroplating.

The temperature of the electrolytic solution to be sprayed and supplied may be at room temperature or the same as the temperature of the electrolytic solution in the original electrolytic treatment operation, but from the viewpoint of promoting chemical dissolution and removal of deposits,
It may also be heated and then supplied by injection.

The removal of deposits on a specific surface of a conductor roll according to the present invention is particularly effective when applied to the acid electrogalvanizing method of steel strips described above.
This includes, but is not limited to, alkaline electrogalvanizing,
It can also be applied to electrolytic tin plating, electrochromic plating, electrolytic chromate treatment, phosphate treatment, other electrochemical conversion treatments, electrodeposition painting, electrolytic cleaning, and other anodic treatments.

Applicable metal strips include cold-rolled steel (common steel, low-alloy steel, special steel) strip, zinc-aluminum, tin, nickel, manganese, copper, or their alloy plating, multi-layer plating steel strip, aluminum, It is also effective as a method for removing deposits from specific surfaces of conductor rolls for electrolytic treatment of copper and other non-ferrous metal strips.

The electrolytic treatment method is not limited to horizontal electroplating or vertical electroplating in which the steel strip is immersed in an electrolytic solution, and can also be applied to double-sided plating, single-sided plating, and partial plating.

For example, a steel strip is used as one pole, an insoluble electrode is arranged as a counter electrode, and this insoluble electrode is opposed to the surface of the steel strip, and at least one conductor roll is arranged, preferably one or more conductor rolls are arranged on both sides of the steel strip. If the electrolytic solution supply to a specific surface of the conductor roll of the present invention is adopted in a method in which the electrolytic solution is injected and supplied only between the electrodes and only the electrolytic treatment zone between the electrodes is filled with the electrolytic solution (see Fig. 4). , a submerged rubber roll currently used in the current vertical electrolytic plating process in which the steel strip 1 is electrolytically treated by repeatedly moving upward, reverse and downward between the conductor roll 4 above the conductor roll 4 outside the electrolyte and the rubber roll 3 below it in the electrolyte. 3 to conductor roll 4. As a result, it has become possible to shorten the power supply interval in the length direction of the steel strip in the general feed direction to about 1/2 or less, or increase the deposition speed several times over the same length. Efforts will be made to realize high-speed plating at high current densities. Of course, in this case, not only the upper conductor roll 4 but also the surface deposits on the lower conductor roll 4 can be easily removed by the present invention.

Normally, the extra-liquid conductor roll 4 above the electrolytic cell is placed only above the electrolytic cell (see reference numeral 4 in Figure 1), but according to the present invention, the upper and lower conductor rolls 4 are arranged above the electrolytic cell to supply power also from the bottom of the electrolytic cell. In the present invention, it is also possible to change to a pair of conductor rolls 4, 4 (see reference numbers 4, 4 in Fig. 4) because it is easy to remove adhesion from the lower conductor roll 4 surface. By doing this, it was possible to increase the number of power supply points from the upper and lower pair of conductor rolls 4, 4, and the power supply amount was doubled without causing an increase in voltage between electrodes even during high-speed plating. . Continuous operation for long periods of time is possible using a higher current supply method. Furthermore, if the liquid-hydrostatic pressure supporting insoluble electrode pad (10 in Fig. 10) developed by the present inventors has an electrolyte injection hole and is replaced with the above-mentioned insoluble electrode, it can support the steel strip without contacting it. The electrolytic reaction can now be carried out in the non-contact support zone, ensuring a sufficient amount of electrolyte supply between the electrodes for the steel strip during high-speed threading, and preventing warping, flapping, and other problems in the strip. The effect of removing the factors that inhibit distance proximity will also be realized. Example 1 A surface-conditioned cold-rolled steel strip having a thickness of 0.6 mm and a width of 900 mm was electrolytically treated continuously at a line speed of 100 m/ml using a vertical electroplating device with upper and lower conductor rolls.

(1) Electroplating conditions Electrolyte spraying device (see Figures 5 and 8) on acidic electrolytic galvanizing liquid contact surface Test under the above conditions revealed that the present invention In the rolls using this method, there was no growth in the zinc windings due to electrolytic deposition on both the top and bottom, and there were no problems with pressure scratches during continuous use for three months.

On the other hand, in the conventional manual grinding and maintenance method, the lower conductor roll becomes coated with zinc within a few hours, causing pressure scratches and voltage increases (fluctuations), making maintenance impossible. Furthermore, even after switching to energization from only the upper roll, press scratches occurred about once per round, requiring a great deal of effort to clean. I also tried installing a whetstone grinding jig on the lower surface of the upper conductor roll over the entire width of the roll, but it was difficult to remove it uniformly. In addition, no particular abnormality was observed when using the method of the present invention, the injection angle with respect to the roll surface was set at 60 degrees toward the entrance or exit side of the strip.

Example 2 Electrogalvanized conductor rolls were maintained in the manner shown in FIGS. 6 and 9.

The electroplating conditions were as follows: The bath of Example 1 was used, and the pH was adjusted to 0.55 by adding sulfuric acid. The conductor roll is N
I-plated stainless steel was used. The electrolysis conditions were carried out at a current density of 100 A/d, and the electrode used was a hydrostatic pressure supported electrode pad having a slit for injecting the electrolyte, which the present inventors had previously proposed (Japanese Patent Application No. 55-28025). .

The conditions of the conductor roll maintenance injection nozzle are as in Example 1.
According to the above, the injection liquid used was the Metsuki bath itself. During continuous electrolysis for one month, there was no occurrence of zinc roll-up, and there were no problems such as voltage build-up, scratches, arc spots, etc.

As explained above, according to the method and apparatus of the present invention, conductor rolls can be easily cleaned with a simple device, and are also significantly effective in cleaning the roll surface, allowing long-term operation of the rolls without replacing them. It has great merits such as being able to do so, and its industrial value is great.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the structure of a vertical electrolytic cell, Fig. 2 is an explanatory diagram showing a known conductor-roll care method, and Fig. 3 is a conductor≦roll care method used in a horizontal electrolyzer. This is an explanation showing. FIG. 4 is a schematic diagram of the upper and lower conductor roll maintenance method adopted in the present invention, FIGS. 5, 6, and 7 are schematic diagrams showing various examples of the conductor roll maintenance method in the present invention, and FIG. 9 and 9 are cross-sectional views showing examples of the structure of the injection nozzle, and FIG. 10 is an overall layout diagram of the maintenance mechanism for the upper and lower conductor rolls in the electrode pad electrolysis method. 1...metal strip, 2...electrolyte, 3...sink roll (non-current rubber roll), 4...conductor roll, 5...・・・
...Care jig, 6...Injection nozzle, 7...
...'Matsuto outer wall, 8...Filter 19...
... Slit, 10 ... Electrolytic pad, 11
, 1 "... pump, 12... hold down roll, 13... oxygen enrichment mechanism, S, S
"······space.

Claims (1)

[Claims] 1. When electrolytically treating a metal strip while supplying electricity to the metal strip through a conductor roll and making an electrolyte exist between the electrodes, the electrolyte is applied to the surface of the conductor roll in a non-contact area of the strip. A method for electrolytic treatment of metal strip, characterized by supplying the metal strip by injection. 2. The method according to claim 1, characterized in that an electrolytic solution containing oxygen or an oxygen-containing gas and enriched with dissolved oxygen is injected and supplied to the conductor roll surface of the non-contact area of the metal strip. 3. An apparatus for electrolytic treatment of a metal strip, characterized in that it has a deposit removing means in which an electrolytic solution spout is directed toward the surface of a conductor roll provided in an electrolytic treatment line in a non-contact area of the metal strip.