JPH01168884A - Method for cleaning metal strip - Google Patents

Abstract

PURPOSE:To prevent detective cleaning by spraying a metal strip with a cleaning soln. under a specified pressure and cleaning the strip by brushing after the lapse of a prescribed keeping time. CONSTITUTION:A surface-polished metal strip 4 is travelled and sprayed with a cleaning soln. from spray nozzles 1a-1c under >=0.25kg/cm<2> pressure. After the lapse of >=1 sec keeping time, the strip 4 is cleaned by brushing with brushing rolls 2a, 2b. The interval L between a position at which the cleaning soln. from the nozzle 1a collides against the strip 4 and a part at which the rolls 2a come in contact with the strip 4 is so regulated as to ensure >=1 sec keeping time. Polishing dust, residue of a grindstone, etc., can easily be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for cleaning a metal strip whose surface has been polished.

<Prior Art> Conventionally, in order to wash and remove rolling oil etc. adhering to metal strips such as cold-rolled steel strips and non-ferrous metal strips, the metal strips were passed through a tank storing a degreasing solution. The rolling oil adhering to both surfaces of the metal strip is removed while the metal strip passes through the degreaser solution. Such degreasing methods are static and the reaction of the degreaser solution on both surfaces of the metal strip is weak (and therefore requires a long degreasing time). Therefore, a long tank is required, which has the drawback of requiring a large space to install the oak.In order to overcome these drawbacks, an electrolytic device is installed inside the tank. There is an electrolytic degreasing method that improves the degreasing power of a degreasing agent solution by incorporating a degreasing agent solution.However, this equipment has the problem of being expensive and the current efficiency used for electrolysis being less than 80%.

In the conventional method, water and degreaser are replenished to maintain the degreaser solution in the tank at a high degree of activity. Therefore, the degreaser solution that can still be used is discharged, which is very uneconomical. Furthermore, in order to increase the degreasing power of the degreasing agent solution, it is necessary to raise the temperature to a high temperature of about 80° C., which requires a large-scale heat source. Furthermore, the speed at which the metal strip passes through the degreasing solution depends on the length of the tank and the capacity of the electrolyzer, making it difficult to increase the speed of operation and requiring major modifications to the equipment. I have a problem.

As a countermeasure for the above-mentioned drawbacks, Japanese Patent Application Laid-Open No. 52-37520 discloses a method in which a plurality of tanks are used to store degreasing solution in order to reduce the amount of degreasing solution waste and to turn it into an aged waste solution with low active alkalinity. are arranged in a cascade manner, and a spray nozzle for a degreasing agent solution, a brushing roll, and a ringer roll are arranged in each tank above each of the plurality of oaks from the front in the direction of movement of the metal strip to be degreased. While the metal strip to be degreased passes above the bath, the degreasing solution is injected onto the metal strip from the spray nozzle to increase the degreasing efficiency, and the effect is further enhanced by subsequent brushing with a brushing roll. A method has been proposed in which the degreasing agent solution adhering to the metal strip is concentrated and then returned to the bath by squeezing the degreasing solution adhering to the metal strip with a ringer roll, and this process is repeated on each bath to continuously degrease the metal strip.

<Problems to be Solved by the Invention> However, the method disclosed in Japanese Unexamined Patent Publication No. 52-37520 does not allow foreign matter adhering to the surface of an ordinary metal strip to be removed by brush cleaning. Although it is easy to remove, metal strips with polished surfaces have fine polishing scratches on the surface, and it is difficult to remove the polishing scum and grindstone scum that has gotten into these scratches, resulting in poor cleaning. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning method that eliminates the problem of poor cleaning of metal strips whose surfaces have been polished.

Means for Solving the Problems> The present invention provides surface-polished metal strips with 0.25
After spraying with a cleaning solution at a pressure of more than kg/cii,
The brush is cleaned after a hold time of 1 second or more has elapsed.

<For production> Generally, the cleaning function includes the following four processes.

■ The process in which the cleaning solution wets the dirt and penetrates ■ The process in which the dirt is separated from the area to be washed ■ The process in which dirt particles are dispersed and protected in the cleaning solution ■ The process in which dirt is removed Brush cleaning is effective in the above items. ■ and ■.

Here, when the method of JP-A-52-37520 is shown in FIG. 3, 1a to 1d are spray nozzles, 28 to
2d is a brushing roll, 3a to 3d are ringer rolls, and the cleaning water from the spray nozzles 1a to 1d hits the contact portions of the brushing rolls 2a to 2d and the metal strip 4. Therefore, this method does not include the step (2) above.

Therefore, the present inventors believe that it is effective to allow a certain amount of time for the cleaning solution described in item (3) to wet the dirt and penetrate, when the surface has fine polishing marks, such as a polished product. The present invention was achieved as a result of conducting various experiments on a method for promoting item ①.

FIG. 2 shows the results of experiments conducted by the inventors. In the figure, the horizontal axis is the time from when the cleaning liquid is sprayed from the spray nozzle until it is brushed by the brushing roll, that is, the keeping time (seconds), and the vertical axis is the spray pressure (kg/d) of the cleaning liquid.

To polish and finish a metal strip, it is common to use a high-speed rotating endless belt, use abrasive oil for lubrication and cooling, and use a ringer roll for wamping. From figure 0 using metal strips treated in this way, 0.25kg/
It can be seen that when cleaning with a brush is performed after a holding time of 1 second or more has elapsed after spraying with a cleaning liquid at a pressure of cm2 or more, the evaluation of cleaning performance is good.

<Example> Fig. 1 shows an example of the apparatus used in the method of the present invention, in which 1a to IC are spray nozzles, 2a and 2b are brushing rolls, 3a to 3d are ringer rolls, and 4
is a metal strip. 5 is a pipe for supplying cleaning liquid.

Then, the cleaning liquid from the spray nozzle a hits the metal strip 4 (the distance between the upright and the part where the brushing roll 2a contacts the metal strip 4 is kept for 1 time).
An interval of at least a second is provided. Other arrangements are the same as before.

Next, specific examples will be described.

503430 steel strip at a polishing speed of 20 m/sin
After polishing and finishing, the plate was passed through the apparatus shown in FIG. 1 for cleaning. At this time, the setting was L-0.7m, the hold time was secured for 2 seconds, the spray pressure was 0.5kg/aa, and the spray amount was 1m for the board width.
Hit 501. /+win.

As a result, contamination on the strip surface was reduced to 1/4 compared to when the holding time was less than 1 second.

Although the amount of spray does not have much effect on the effect, it is preferable for boat fishing to be at least 10 Il/inch per meter of board width.

[Brief explanation of the drawing]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a graph showing the relationship between keep time and spray pressure, and Fig. 3 is a side view for explaining a conventional metal strip cleaning method. . 1... Spray nozzle, 2... Brushing roll, 3... Ringer roll, 4... Metal strip. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 3 Figure 2 Evaluation of cleanability Keeping time (seconds)

Claims (1)

[Claims] 0.25kg/c of metal strip with surface polishing
A method for cleaning a metal strip, which comprises spraying with a cleaning liquid at a pressure of m^2 or more and then cleaning with a brush after a holding time of 1 second or more has elapsed.