JP3482290B2 - Roll surface foreign matter removal device to prevent surface defects from occurring on electroplated products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc-based electroplating equipment using a horizontal cell, and more particularly to a grinding / polishing device for effectively removing foreign matter adhering to a current-carrying roll.

[0002]

2. Description of the Related Art A technique for imparting corrosion resistance to a steel sheet by plating a zinc-based metal or metal alloy on the surface of the steel sheet is currently widely used.・ Continuing to expand applications, mainly in automobiles. Electroplating methods for zinc-based metal on steel sheets can be broadly divided into three types, horizontal cells, vertical cells, and carousel cells, in the electrode arrangement. This structure is the same in that the steel sheet to be plated is negatively charged by bringing it into contact with an energizing roll, the electrodes are positively charged, and the plating solution is filled between both electrodes. Among them, in the horizontal type cell, since a large amount of plating solution is always attached to the energizing roll, foreign matter in the plating solution adheres to the energizing roll, and the foreign matter is dented in a continuous pattern on the product. Cause defects.

Further, due to the fluctuation of the contact pressure between the steel sheet and the current-carrying roll, zinc is deposited not on the steel sheet but on the current-carrying roll.
The so-called zinc winding phenomenon occurs, which also causes continuous defects in the product at the roll pitch. When such a defect occurs, there are two countermeasures, one is to reduce the defect through a pressure-regulating process again to relieve it and the other is to divide only the defective part in the adjusting process. Therefore, it is necessary to immediately remove the dot-like or zinc-wrapped foreign matter adhering to the current-carrying roll because of the high cost and increase in the cost of the product. For removing adhered foreign substances, a device for pressing a buff against a current-carrying roll for the purpose of polishing, and Japanese Patent Publication No. 61-15
There is a device for pressing the continuous abrasive paper against the energizing roll as disclosed in Japanese Patent No. 3296, and a method for further removing scraps from the continuous abrasive paper with a doctor blade as disclosed in Japanese Utility Model Publication No. 6-25360.

[0004]

A buff-type polishing apparatus as a method for removing foreign matter adhering to the surface of an energizing roll has a problem in that a large amount of plating solution adheres to the roll surface in a horizontal cell between the energizing roll and the buff. Polishing efficiency is poor due to a large amount of plating solution entering, and although some effect is seen in removing zinc winding, little effect is seen in removing spot-like foreign matter. As a countermeasure, if the pressing force of the polishing buff is set to a high pressure, it becomes difficult to remove the foreign substances that are caught between the polishing buff and the energizing roll, and on the contrary, the energizing roll may be damaged and sudden roll replacement is required. This will reduce productivity.
Further, the deterioration rate of the polishing buff is increased, which leads to deterioration of workability and cost due to an increase in the frequency of replacement work.

In addition, the doctor blade device does not need to consider the installation position or the like in a process roll such as a deflector roll or a bridle roll which is not exposed to liquid, but in the application to a current-carrying roll of a horizontal cell to which the plating liquid adheres. Has the problem of liquid splashing. In the prior art, when abrasive paper such as Japanese Utility Model Publication No. 6-25360 is also used, it is inevitable that abrasive grains fall, and therefore a doctor blade for collecting the abrasive grains is installed in the latter stage of the polishing device. Therefore, the removed foreign matter and the plating solution scatter on the surface of the steel plate and on the plating cell.To prevent this, a liquid receiving gutter for prevention of scattering and a scattering prevention cover are required, which increases equipment costs and maintenance costs. Had been connected to. INDUSTRIAL APPLICABILITY The present invention is an inexpensive and easy-maintenance, electrically-conductive roll surface capable of effectively removing both spot-like adhered foreign matter and zinc winding adhered to the electrically-conductive roll surface without causing scratches on the electrically-conductive roll surface. An object is to provide a device for removing adhered foreign matter.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a foreign substance in a zinc-based electroplating horizontal cell in which a doctor blade device and a buffing polishing device are installed in this order with respect to the rotating direction of the current-applying roll in the horizontal zinc-based electroplating cell. It is a removal device. The width of the blade of the doctor blade should be wider than the width of the energizing roll, and it is desirable to remove foreign substances over the entire length of the energizing roll. It is prevented from getting caught between the tip of the energizing roll surface and the surface of the energizing roll, and this doctor blade removes most of the plating liquid on the surface of the energizing roll. It is characterized by enhancing the effect of removing zinc.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described with reference to specific examples. FIG. 1 is a diagram showing an outline of arrangement of a plating cell and an apparatus of the present invention. In FIG. 1, in a horizontal plating cell 2 for performing zinc-based electroplating on the surface of a steel sheet 1, the steel sheet 1 is negatively charged by an energizing roll 4, and the electrode 3 is, on the contrary, positively charged. 6 is full. The plating liquid flows out from the header 7 at the center of the plating cell, passes between the electrode and the steel plate, is dammed by the energizing roll, and then returns to the circulation tank. In order to secure the contact pressure between the current-carrying roll and the steel sheet and improve the current-carrying efficiency, the backup roll 5 is rolled down from below.

In this plating cell structure, if there is a foreign substance on the surface of the steel plate or in the plating solution, the energizing roll 4
It is sandwiched between the backup roll 5 and the energizing roll 4.
Is crimped to. Point-like foreign matter 8 once crimped to the energizing roll
Causes continuous flaws on the steel plate at the pitch of the energizing roll circumference, making it impossible to collect acceptable products. Also,
When the rolling force of the backup roll 5 becomes weak,
The contact resistance between the current-carrying roll 4 and the steel sheet increases, and a potential difference is generated. Due to this potential difference, the zinc that should be electrodeposited on the steel sheet deposits the sheet-like foreign matter 9 on the surface of the current-carrying roll. This electrodeposition phenomenon is generally referred to as zinc winding, but like the dot-like foreign matter, the pattern of electrodeposited zinc is continuously transferred to the steel sheet at the pitch of the energizing roll circumference, and Cause

In the present invention, near the lowest point of the energizing roll,
In order to remove two types of foreign matter, that is, point-like foreign matter and surface foreign matter that have adhered to the energizing roll,
Doctor blade 10 in the front stage and buff type polishing machine 1 in the rear stage
1 is installed. First, the dot-like foreign matter is removed from the surface of the energizing roll by the blade 12 of the doctor blade, and most of the plating solution is also removed, so that the removed foreign matter drops together with the removed plating solution. The contact position between the tip of the blade of the doctor blade and the surface of the energizing roll is set to 30 ° to 150 ° with respect to the rotation direction from the lowest point of the energizing roll in order to drop the removed foreign matter toward the exit side in the plate passing direction. If it is less than 30 °,
After removing the plating solution on the surface of the energizing roll with a doctor blade, the plating solution adheres to the surface of the energizing roll again, reducing the effect of the buff type polishing apparatus.
If it is larger than °, the removed foreign matter and the removed plating solution will drop due to inertia to the entrance side of the energizing roll in the sheet passing direction.

Further, in this range, it is not necessary to provide a cover or a gutter for scattering prevention, and the equipment cost can be suppressed. Although the removed foreign matter falls to the exit side in the sheet passing direction, since the exit side in the sheet passing direction is a position where it is not caught between the energizing roll and the backup roll, it does not adhere to the energizing roll again. The doctor blade is fixed by a holder 13 installed on a frame above the energizing roll.

Next, the sheet-like foreign matter is removed by a buff-type polishing apparatus 11 installed at a stage subsequent to the doctor blade in the rotating direction of the energizing roll. Most of the plating liquid on the surface of the energizing roll is removed by the doctor blade in the previous stage, so the polishing removal effect of the surface foreign matter of the buff can be sufficiently obtained under light pressure, the life of the buff is extended and the buff is extended. The flaws on the energizing roll due to the cause are also eliminated. The surface foreign matter removed by the buff type polishing device and the abrasive grains of the buff itself are extremely fine and do not affect the product.Therefore, the installation position of the buff type polishing device is relative to the rotating direction of the energizing roll. There is no problem if it is after the doctor blade. Since the width of the buff itself is narrow, the screw 14 reciprocates in the width direction.

The blade material of the doctor blade is a plating solution.
Is a strong acid and is in contact with the energizing roll.
Therefore, select a resin blade that has both acid resistance and insulation.
Is desirable, but the hardness of the material makes it possible to remove foreign matter and
35H to affect life _BNeed to manage more
is there. 35H_BIn the following cases, wear of the blade will be significantly faster.
And accordingly, the foreign matter removal effect is significantly reduced.
Therefore, the frequency of blade replacement increases. Increased replacement frequency is due to
This is not desirable because it increases the cost of entry and reduces workability.

Further, the contact pressure between the tip of the blade of the doctor blade and the surface of the energizing roll also affects the foreign matter removing effect and the life of the blade, and therefore must be controlled to 20 to 200 g / cm. If it is 20 g / cm or less, the point-like foreign matter cannot be removed from the surface of the energizing roll because of strong pressure bonding force. In addition, the removal amount of the plating solution is poor, and the effect of the buffing type polishing device installed in the subsequent stage is also reduced. On the other hand, even at a high pressure of 200 g / cm or more, the effect of removing foreign matter did not increase, and conversely, there was an adverse effect of flaws on the energizing roll.

This is because the blade warps due to high pressure and the tip of the blade floats, and foreign matter is trapped between the floating blade tip and the energizing roll. is there. The contact pressure is adjusted by adjusting the air pressure in the pressure tube 15 of the doctor blade. This is done by operating the pressure valve 16 and the pressure gauge 17 of the doctor blade operation panel. Further, in order to prevent foreign matter from being caught in the blade, it is effective to slide the blade in the width direction. A force is applied to the foreign matter in a direction perpendicular to the biting direction, and the foreign matter rotates at the tip of the blade to be removed together with the plating solution.

As for this sliding speed, the ratio of the peripheral speed to the energizing roll must be 0.001 to 0.01. 0.0
When it is 01 or less, the effect of preventing foreign matter from being caught is weak, and when it is 0.
This is because if it is 01 or more, the effect is not changed and the life of the blade is shortened. For the sliding speed, the signal from the PLG 19 of the speed master roll 18 is set to the doctor blade control board 20.
Taken in, and based on it, doctor blade sliding solenoid valve 2
A signal is given to 1 to operate the air cylinder 22.

[0016]

【Example】

(Example 1) Phenolic resin blade (thickness 5 mm, width 75
mm, Length 2300 mm, Blade Tip Angle 30 °, Hardness 38
H _B , doctor blade sliding pitch 0.005) is used to change the contact pressure between the energizing roll and the tip of the blade, the frequency of generation of point foreign matter by the doctor blade, the life of the blade, zinc buffing with a buffing grinder Verification of the removal effect was performed on the actual machine. The result is as shown in FIG. A reduction force of 20 g / cm or more is required to remove the dot-like foreign matter, and together with the increase in the reduction force, the zinc winding removal effect also increases. On the other hand, the service life of the blade was remarkably reduced when it exceeded 250 g / cm, and when it was 200 g / cm or more, flaws occurred on the roll. The life is 5 m in Fig. 3
It was the time when m was reached. Therefore, the contact pressure between the energizing roll and the blade tip is set to 20 g / cm or more and 200 g / cm or less.

(Example 2) Phenolic resin blade (thickness 5)
mm, width 75 mm, length 2300 mm, blade tip angle 30
FIG. 4 shows the results of verifying the foreign matter removing effect and the life by changing the hardness using a temperature of 0.1 °, a rolling force of 100 g / cm, and a doctor blade sliding pitch of 0.005). When the hardness is 35 H _B or less, the foreign matter removing effect is reduced and the life is shortened. Therefore, the hardness of the blade is 35 H _B or more.

(Example 3) Phenolic resin blade (thickness 5)
mm, width 75 mm, length 2300 mm, blade tip angle 30
°, hardness 38 H _B , rolling force 100 g / cm),
By changing the sliding pitch of the doctor blade, the life of the blade and the state of flaws on the energizing roll were verified. The results are shown in FIG. Doctor blade sliding pitch 0.01
With the above, the life has started to decrease. Also, 0.00
During operation at 05, linear flaws occurred on the energizing roll. Doctor blade sliding pitch 0.001 or more,
It is set to 0.01 or less.

[0019]

As described above, according to the present invention, it occurs on the surface of a zinc-based electroplating current-carrying roll using a horizontal cell. For removing spot-like foreign substances and surface foreign substances called zinc winding, by arranging a doctor blade in the front stage of the energizing roll rotation direction and a buff-type polishing device in the rear stage, it is possible to effectively remove the foreign substances. It was possible to improve the yield and reduce the cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of arrangement of a plating cell and an apparatus of the present invention,

FIG. 2 is a graph showing the relationship between the contact pressure between the energizing roll and the tip of the blade and the foreign matter removal effect / blade life.

FIG. 3 is a view showing the shape of a doctor blade,

[Fig. 4] Hardness of the doctor blade and foreign matter removal effect
Graph showing the relationship with blade life

FIG. 5 is a graph showing the relationship between doctor blade sliding pitch and blade life.

[Explanation of symbols]

1 steel plate 2 Horizontal plating cell 3 electrodes 4 conductor roll 5 Backup roll 6 plating solution 7 header 8 point foreign matter 9 Surface foreign matter 1 0 doctor blade 1 1 Buff type polishing machine 1 2 blade 1 3 holder 1 4 screw 1 5 pressure tube 1 6 pressure valve 1 7 Pressure gauge 1 8 speed master roll 1 9 PLG 20 Doctor blade control panel 2 1 Doctor blade sliding solenoid valve 2 2 Air cylinder

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References: Kaihei 6-25360 (JP, U) Patent 3403876 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C25D 7/06

Claims (4)

(57) [Claims] 1. In a current-carrying roll of a zinc-based electroplating equipment for steel sheets using a horizontal cell, a doctor blade device and a buff-type polishing device are arranged in this order with respect to the rotating direction of the current-carrying roll, and the doctor blade and the roll are brought into contact with each other. A roll surface foreign matter removing device for preventing the occurrence of surface defects in an electroplated product, wherein the position is 30 ° to 150 ° from the lowest point of the roll in the rotation direction. 2. The hardness of the doctor blade is 35 H _B.
The roll surface foreign matter removing device for preventing the occurrence of surface defects of the electroplated product according to claim 1, which uses the resin blade described above. 3. The roll surface foreign matter removing device for preventing the occurrence of surface defects in an electroplated product according to claim 2, wherein the contact pressure between the tip of the blade of the doctor blade and the energizing roll is 20 to 200 g / cm. 4. The doctor blade slides in the width direction, and the ratio of the sliding moving speed to the energizing roll peripheral speed is 0.001 to 0.
The apparatus for removing foreign matter on a roll surface according to claim 3, wherein the electroplated product is 01.