JPH04281000A - Method for continuous electropolishing and device therefor - Google Patents

Abstract

PURPOSE:To enable the improvement of surface quality and increase of produc tion yield by stable mirror finishing by an in-process detection and control of the electropolishing effect. CONSTITUTION:In a process of continuously electropolishing metal strips, etc., after materials to be electropolished are electropolished in an electropolishing vessel, white light or a laser beam 8a is projected on the surface 1a of the materials from the oblique direction to the surface 1a. The luminous intensity of the reflected light from the projected light is detected to determine the glossiness of the surface 1a of the material and is controlled so that the glossiness may be the prescribed one.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic polishing method and apparatus for stably achieving a mirror finish on a metal strip in the process of continuously electropolishing the metal strip.

0002

2. Description of the Related Art Several examples have been reported in which electrolytic polishing is used as a method for mirror-finishing the surface of metal strips and the like. Compared to mechanical polishing or chemical polishing, the method using electrolytic polishing allows continuous and industrial mass production to be easily realized.

For example, in the production of unidirectional silicon steel sheets, Japanese Patent Publication No. 52-24499 and Japanese Patent Publication No. 56-4
As disclosed in Japanese Patent No. 150, it has been announced that a unidirectional silicon steel plate with extremely low core loss can be produced by mirror-finishing the surface of the steel plate. Further, Japanese Patent Application Laid-Open No. 18075/1983 discloses equipment having an electrolytic polishing process in order to industrially and continuously reduce the iron loss of unidirectional silicon steel sheets.

0004

[Problem to be solved by the invention] However, if electrolytic polishing is adopted in the process, it will lead to a significant increase in cost, and therefore, operating without understanding the effects of electrolytic polishing will waste a large amount of electricity. Therefore, it is desirable to carry out production while monitoring the mirror finish state of the surface of the electrolytically polished material by some means. For this reason, there are cases where the mirror finish status is determined using the surface gloss value of the surface of the electrolytically polished material.

[0005] As a method for measuring the surface gloss value of metal strips, etc., there is a method that uses the apparatus described in JIS Z8741 ``Method for measuring specular gloss''. Since it is necessary to sample the area, it cannot be used for continuous electrolytic polishing processes. Furthermore, with the method of measuring the surface gloss value based on visual judgment by an operator, quantitative measurement of the gloss value is not possible, and therefore stable electrolytic polishing cannot be performed at all times.

[0006] Regarding such problems, the above-mentioned publication does not mention anything. An object of the present invention is to provide a method and apparatus for electrolytic polishing of metal strips, etc., which solves the above-mentioned problems and enables a stable mirror finish.

[0007]

[Means for Solving the Problems] The continuous electrolytic polishing method of the present invention measures the gloss value of the surface of the electrolytically polished material after electrolytic polishing in the process of continuously electropolishing a metal strip, etc. This method is characterized by controlling the electrolytic polishing conditions in-process so that the value becomes a predetermined value.

[0008]The continuous electrolytic polishing apparatus of the present invention has the following features:
In the process of continuous electrolytic polishing of metal strips, etc., white light or laser light is projected onto the surface of the electrolytically polished material from an electrolytic polishing tank and from an oblique direction on the surface of the electrolytically polished material after electropolishing. It is equipped with an instrument that detects the intensity of reflected light to determine the gloss value of the surface of the electrolytically polished material, and a control device that controls the gloss value of the surface of the electrolytically polished material after electropolishing to a predetermined value. It is characterized by this.

[0009]

[Function] In the present invention, a gloss measuring device is installed in the electrolytic polishing process, and the reason for this will be explained below. Unlike mechanical polishing, electrolytic polishing does not necessarily reduce the surface roughness of the electrolytically polished material depending on the amount of polishing. That is, since the surface of the electrolytically polished material is scraped off by the ions in the electrolytic polishing solution, it does not work to crush minute irregularities on the surface, but rather to remove the surface texture. Therefore, although the surface roughness value decreases to a certain level, it does not decrease indefinitely.

According to the research conducted by the present inventors, it has become clear that in order to evaluate such a process, it is optimal to use the degree of bare metal exposure of the electrolytically polished material, that is, the gloss value. Ta. The equipment for measuring gloss is JISZ8.
It is best to use the device described in 741 “Method for Measuring Specular Glossiness” as is, but since the optical system of this device has a structure equipped with a slit and a lens, the surface to be measured is located at the focal point of the lens. It is assumed that the state is fixed at . Therefore, in the process of continuously electrolytically polishing a metal strip or the like, it is difficult to use the device described in JIS Z8741 as an in-process measuring device due to vibrations caused by the movement of the electrolytically polished material. Alternatively, it may be possible to fix the electrolytically polished material using an auxiliary roll or the like, but this would complicate the production line.

[0011] However, in the process of continuous electrolytic polishing on an industrial scale, highly accurate gloss measurement is not necessarily required, and in many cases it is sufficient to guarantee measurement accuracy at the level necessary for operation. . The present inventors investigated a measuring method and device that have the precision required for the process of continuous electrolytic polishing, and found that white light or laser light is projected onto the surface of the electrolytically polished material from an oblique direction, and the reflected light is reflected. It has been found that there is no practical problem if the intensity of the light is detected and the gloss value of the surface of the electrolytically polished material is determined from the intensity of the reflected light. Figure 3 shows an example of determining the gloss value of the surface of the electrolytically polished material from the intensity of the reflected light of white light, and Figure 4 shows an example of determining the gloss value of the surface of the electrolytically polished material from the intensity of the reflected light of the laser beam. This is an example. In terms of measurement accuracy, it is preferable to use white light as the light source, but in terms of device fabrication, it is more advantageous to use laser light as the light source.

Generally, the reflection intensity of light is strongly influenced by the surface roughness value and reflectance of the reflective surface, but as mentioned above, since electrolytic polishing works to remove the surface texture, the surface roughness value It is presumed that it is almost constant and only the reflectance changes. Therefore, even with a simple method and device for detecting the intensity of reflected light, sufficient gloss value measurement can be performed in the electrolytic polishing process.

Further, when electrolytic polishing is performed using the apparatus according to the present invention, the mirror finish state of the electrolytically polished material can be observed in-process, so operations can be carried out while grasping the effects of electrolytic polishing. Therefore, by changing electrolytic polishing conditions such as electrolytic polishing current value and sheet passing speed so that the surface gloss value becomes a predetermined value, a stable mirror finish can be achieved at all times.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus of the present invention is shown in FIG. Figure 1
In the process, the electrolytically polished material 1 such as a metal strip is transferred from a coiled state to an electrolytic polishing tank 4 via a pickling tank 2 and a first cleaning tank 3.
A mirror finishing process is performed. Furthermore, a drying device 6 for drying the cleaning liquid etc. that passes through the second cleaning tank 5
After leaving the drying device 6, the surface gloss value is measured by a gloss measuring device 7.

The reason why the gloss measuring device 7 is placed after the drying device 6 is to prevent measurement errors from occurring due to the cleaning liquid and electrolytic polishing liquid adhering to the surface of the electrolytically polished material 1. A looper, welding machine, etc. may be placed before the electrolytically polished material 1 is wound into a coil, but there is no particular restriction on the location where the gloss measuring device 7 is placed as long as it is after the drying device. .

As a device for measuring gloss, as schematically shown in FIG.
eg. It is sufficient to use a structure in which the steel plate surface 1a is irradiated with light and the reflected intensity is received using the first photodetector 9. The second photodetector 10 shown in FIG.
This serves as an intensity monitor for the laser beam 8a.
This is to correct measurement errors caused by intensity changes. Further, the light intensity signals detected by the photodetectors 9 and 10 are transmitted to the arithmetic unit 12 via the amplifier 11, and the arithmetic unit 12 calculates a gloss value. The calculated gloss value is displayed to the operator by the output device 13.

The surface gloss value of the electrolytically polished material measured by the gloss measuring device 7 is transmitted to a central controller 14 that controls the entire electrolytic polishing process. The central control device 14 includes:
Signals from other instruments (not shown) are also transmitted, and each part of the process is adjusted and operated through the control equipment so that the entire process performs a predetermined function. The embodiment shown in FIG. 1 has a winding control device 15 for the electropolishing material 1 and a current control device 16 for the electrolytic polishing tank 4 as examples of the control devices described above, and the central control device 8 The mirror finish status of the electrolytically polished material 1 is determined from the surface gloss value, and the winding control device 15 and current control device 16 are operated so that the mirror finish can be stably performed.

FIG. 3 is a diagram showing the processing flow of the electrolytic polishing method according to the present invention. Next, using the apparatus shown in FIGS. 1 and 2, continuous electrolytic polishing was performed on the surface of the steel plate, and at this time, the mirror finish state of the surface of the steel plate was examined due to changes in the polishing current value. Figure 5
This is an example showing the correspondence between the polishing current value and the measured gloss value, and it can be seen that the measured gloss value satisfactorily expresses the mirror finish state of the electrolytically polished material.

Furthermore, the operation was carried out by controlling the current value so that the value measured by the gloss measuring device 7 remained approximately constant during electrolytic polishing. Figure 6 shows an example of the comparison results between when the current value is controlled and when it is not performed based on the results of gloss measurement. Electrolytic polishing with current value control achieves a consistently stable mirror finish. I can see that it is being done.

[0020]

[Effects of the Invention] As explained above, according to the present invention,
In the process of continuously and industrially electropolishing metal strips, etc., it becomes possible to detect and control the effects of electrolytic polishing in-process. As a result, a stable mirror finish can be achieved, thereby improving the surface quality of the product and increasing the yield.

[Brief explanation of the drawing]

FIG. 1 is an overall explanatory diagram schematically showing an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing an embodiment of the gloss measuring device of the present invention.

FIG. 3 is a diagram showing the processing flow of the electrolytic polishing method according to the present invention.

FIG. 4 is a diagram showing an example of determining the gloss value of the surface of the electrolytically polished material from the intensity of reflected white light.

FIG. 5 is a diagram showing an example of determining the gloss value of the surface of the electrolytically polished material from the intensity of the reflected laser beam.

FIG. 6 is a diagram showing an example of the correspondence between polishing current values and gloss measurement values.

FIG. 7 is a diagram showing a specific example of electropolishing by the electropolishing method of the present invention.

[Explanation of symbols] 1 Electrolytically polished material 1a Steel plate surface 2 Pickling tank 3. First cleaning tank 4 Electrolytic polishing tank 5 Second cleaning tank 6 Drying equipment 7 Gloss measurement device 8 Semiconductor laser 8a Laser light 9 First photodetector 10 Second photodetector 11 Amplifier 12 Arithmetic device 13 Output device 14 Central control unit 15 Control equipment 16 Current control equipment

Claims (2)

[Claims] Claim 1: In the process of continuously electrolytically polishing a metal strip or the like, the gloss value of the surface of the electrolytically polished material after electrolytic polishing is measured, and the electrolysis is performed in-process so that the gloss value becomes a predetermined value. A continuous electrolytic polishing method characterized by controlling polishing conditions. 2. In the process of continuously electropolishing a metal strip or the like, white light or laser light is projected onto the surface of the electrolytically polished material from an electrolytic polishing tank and from an oblique direction of the surface of the electrolytically polished material after electropolishing. , an instrument that detects the intensity of the reflected light of the projected light to determine the gloss value of the surface of the electrolytically polished material, and a control device that controls the gloss value of the surface of the electrolytically polished material after electropolishing to a predetermined value. A continuous electropolishing device characterized by comprising: