JPS63119916A - Manufacture of steel plate excellent in sharpness - Google Patents

Abstract

PURPOSE:To manufacture the steel plate excellent in with good operability with having the specified surface roughness by rolling with the rolling roll having a fine corrosion pit with a corrosion work a steel plate after smoothing the surface of said plate. CONSTITUTION:After smoothing the surface of a steel plate the above plate is rolled by the rolling roll having a fine corrosion pit on the surface. A film 2 is affixed on the surface of the roll on which a bright finishing, etc., is executed and said roll 1 is dipped in a corrosion liquid 3. The part on which no film is affixed is thus corroded. Thereafter said film 2 is removed and a fine corrosion pit is formed on the roll 1 surface. Said corrosion part is scores - hundreds muphiand several mu - hundreds mu in depth suitably. The steel plate of good sharpness with having the necessary surface roughness at the working time is thus obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention improves the sharpness of the steel plate itself by using rolling rolls with fine corrosion holes obtained by corrosion processing in the production of cold-rolled steel plates, etc. The purpose of this invention is to improve the sharpness of the steel sheet after surface treatment such as painting or plating.

[Conventional technology]

Regarding the sharpness of a steel plate, the surface average roughness (Ra) of the rolling roll used to roll the steel plate - the number of peaks of surface irregularities (ppI
) and surface waviness height (Wz), but these factors that further affect the sharpness of the steel sheet are the roll surface finish (dull finish) after polishing the roll surface by shot machining, electrical discharge machining, laser machining, etc. It depends on the condition.

[Problem that the invention attempts to solve]

Among these, shot processing finishes the surface by projecting iron particles called a grid onto the roll surface, and although it has the advantage of short processing time, it also causes large waviness on the roll surface and reduces PPI. On the other hand, electrical discharge machining has the disadvantage that the roll surface is melted by electric discharge to obtain unevenness, and while the PPI on the roll surface is relatively large, the machining time is long and the roll surface has large waviness. It has the disadvantage of becoming. Furthermore, laser processing is a process in which a laser beam is projected onto the roll surface to form unevenness on the roll surface, and it is an extremely excellent processing method that increases the PPI of the roll surface and reduces waviness.
The problem is that the machining time is very long.

In this way, all three methods improve operability (processing time) and image clarity (
Therefore, in shot machining and electric discharge machining, the roughness of the roll surface is reduced to improve the sharpness of the steel sheet. However, in this case as well, flaws (
There was a limit to reducing surface roughness (Ra) because scratches, punching scratches, etc.) and scratches during processing (mold galling, etc.) were likely to occur, and paint adhesion also decreased. Further, although laser processing has good image clarity on the roll surface as described above, it also has the problem of a long processing time and that it is very difficult to control the processing conditions.

The present invention was devised in view of the above problems, and by using a rolling roll whose surface has been finished using a new processing method, it improves the sharpness of the steel plate itself and the sharpness of the steel plate after surface treatment. The aim is to achieve improvements in operability as well as improvements in performance.

c.Means for solving problems] The inventors first used various cold-rolled steel sheets.

We analyzed each factor that affects image clarity after mounting. Among them, the relationship between surface factors and sharpness of cold-rolled steel sheets when painting conditions are constant is as follows:
) PPI: Peak count number (count level 1μ or more) Wz: Waviness height μ) Person: Constant However, the sharpness here is determined by visual inspection, and the smaller the number, the better the level. The sharpness factor of the steel plate shown in equation (1) above is:

This is mainly due to the transfer of the rolling roll surface, so in order to obtain a steel plate with high sharpness, the roll surface roughness Ra)
- The peak count number (PPI), waviness height (Wz) must be controlled.

However, the above-mentioned three roll processing methods have problems with either image clarity or operability, so the present inventors developed a new roll processing method and The present inventors have devised a method of rolling a steel plate using rolling rolls.

That is, the method for producing a steel plate according to the present invention has a basic feature of rolling a steel plate with a smooth surface using rolling rolls having fine corrosion holes on the surface due to corrosion processing, and has excellent image clarity. This is to obtain a steel plate.

〔Example〕

Before describing specific embodiments of the present invention, a method for treating the surface of a rolling roll used in the embodiments will be explained.

This new processing method applies gravure plate technology to create gcm-sized dents (corrosion holes) on the roll surface due to corrosion. That is,
The film (2) is pasted on the surface of the roll (1) which has been given a bright finish as shown in Fig. 1(a), as shown in Fig. 1(b), and then the film (2) is pasted as shown in Fig. 1(c). Then, the surface of the roll (1) is immersed in the corrosive liquid (3). Then, the parts of the film (2) that are not stuck are corroded. Thereafter, the film (2) is removed as shown in FIG. 2(d) to complete the processing.

Corroded areas on the roll surface in the above method range from several tens of microns to
It has a circular, square, diamond, etc. shape of several hundred micrograms,
The depth is from several μ to several 100 μ.

According to this method, the only waviness on the roll surface is the waviness during polishing (Wz = 0.1 to 0.3μ), which is much smaller than the waviness during shot machining or electric discharge machining (Wz = 1 to 10μ). . Furthermore, the surface roughness and peak count number can be freely selected by changing the size and frequency of the corroded area. Furthermore, the time required for corrosion is several minutes to several 10 minutes.

Next, an experiment was conducted to compare the sharpness of steel sheets obtained when actually rolled using rolling rolls subjected to the various surface treatments described above.

The experiment will be explained below.

The rolling roll used was a roll with fine corrosion holes formed on its surface through the corrosion process described above.

These are rolls that have been subjected to shot processing, rolls that have been subjected to electrical discharge machining, and rolls whose surface has been processed by laser processing.

These rolls were used to roll cold-rolled steel sheets of the same material and shape, and the relationship between the surface roughness (Ra) and sharpness of the steel sheets obtained as a result of rolling was investigated, and the results are shown in Figure 2. I got it. As is clear from the figure, as the surface roughness of the steel plate rolled by the roll processed by shot machining and electric discharge machining increases, the waviness during machining increases, and therefore, as shown in equation (1) above, The image sharpness deteriorates due to the additive effects of surface roughness and waviness height. In comparison, in the case of a steel plate rolled by a roll whose surface was processed by laser processing and corrosion processing, even if the surface roughness increased, the waviness did not change, so there was almost no change in sharpness.

From the above results, it can be seen that by rolling using a corroded roll as in the present invention, it is possible to produce a steel plate with good image clarity while having the surface roughness required for the steel plate during processing.

Furthermore, when comparing the surface processing time of the rolls used for each rolling, the time required for one round of corrosion of the corroded roll (several minutes to several tens of minutes) is longer than the time required for other processing methods (especially laser processing). (from several tens of minutes to several hours), it can be much shorter. Furthermore, by increasing the depth of corrosion, it is possible to reuse the roll by simply polishing it after use, which is a great advantage compared to other processing methods (repeating polishing and processing after each use). Therefore, when rolling is performed using corroded rolls as in the present invention, operability is improved.

〔Effect of the invention〕

As explained above, according to the steel plate manufacturing method number ζ of the present invention,
This method has the excellent effect of making it possible to produce a steel plate with good image clarity while having the necessary steel plate surface roughness during processing, and further improving operability during production.

[Brief explanation of the drawing]

FIGS. 1(a), 1(b), 1(c), and 1(d) are explanatory diagrams showing a surface corrosion processing method for a rolling roll used in the method of the present invention. FIG. 2 is a graph showing the correlation between the surface roughness and image clarity of steel sheets rolled by corrosion processing rolls, laser processing rolls, shot processing rolls, and electric discharge processing rolls. In the figure, (1) indicates a rolling roll, (2) a film, and (3) a corrosive liquid. Patent applicant: Nippon Kokan Co., Ltd. Inventor: Shigeru Furuichi Kimima
Masaru Kosaka spread out
Masahiro Ogawa Figure 1 (G) (b) (°) (d)
2 Rc (μ)

Claims (1)

[Claims] Corrosion processing after smoothing the surface of the steel plate A rolling mill with fine corrosion holes on its surface due to The steel plate is rolled by a roll. A method for producing a steel plate with excellent image clarity.