JPH08103801A - Method for producing stainless steel foil having excellent antiglare property - Google Patents

Abstract

PURPOSE: To provide the production method of a stainless steel foil excellent in antidazzle property. CONSTITUTION: Rough rolling is executed at a draft of >=15% to <=30% by using a roll of >=0.20μm to <=1.20μm surface roughness Ra, successively, intermediate rolling is executed at a draft of >=5% to <=15% with using a roll of >=0.01μm to <=0.20μm surface roughness Ra. Successively, finish rolling is executed at a draft of >=1% to <=10% with using a ceramic roll of >=0.01μm to <=0.05μm surface roughness Ra. Also as necessary, bright annealing is executed following to finish rolling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stable method for producing a stainless steel foil having excellent surface properties and excellent antiglare properties.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a stainless steel sheet requiring antiglare property, a method of roughening the surface of a stainless steel sheet by cold rolling using a roll having a rough surface or after cold rolling or cold rolling is used. A method of roughening the surface of a stainless steel sheet by subjecting pickling after hot rolling and annealing to electrolysis or immersion in an aqueous solution containing nitric acid or hydrofluoric acid is used.

As an example of the above-mentioned method, a technique of imparting antiglare property to a stainless steel plate whose surface has been roughened by cold rolling is pickled, for example, as disclosed in Japanese Unexamined Patent Publication No. 5-163528. Surface roughness (Ra) is 0.5-10.
There is a pickling method in which a 0 μm stainless cold-rolled steel sheet is bright annealed and then finally immersed in a mixed acid of nitric acid and hydrofluoric acid.

However, in this method, the surface of the stainless steel plate is remarkably roughened by cold rolling or pickling, so that dirt such as dust is liable to be attached to the surface, impairing the aesthetics of the surface and further deteriorating the corrosion resistance. Further, the acid used for pickling is difficult to handle and is not preferable in terms of environmental hygiene.

However, the prior art has not proposed a method for imparting antiglare property other than a cold rolling method for remarkably roughening the surface or a method for performing pickling treatment, and stainless steel having satisfactory antiglare property is not proposed. There was no stable manufacturing method for steel sheets.

The material of the rolling roll used for this cold rolling is the conventionally used high speed steel (high speed steel).

[0007] When a foreign substance is mixed between the surface of the rolling roll and the stainless steel plate during rolling, the high-speed roll causes plastic deformation of the rolling roll to cause continuous defects on the surface of the stainless steel plate.

Further, since a large-diameter roll is used at the time of finish rolling, there is a high possibility that defects will occur due to an increase in intrusion of lubricating oil.

This is because there is a higher possibility that foreign matter will be mixed in when a large amount of lubricating oil enters.

[0010]

In the method for producing a stainless steel foil having excellent antiglare properties, an oil pit which is generated during cold rolling is one of those that reduce surface gloss.

This is because when a large amount of lubricating oil penetrates between the roll surface and the stainless steel foil surface during cold rolling, the rolling oil is sealed between the stainless steel foil surface and the roll surface, and The surface of the stainless steel foil is deformed by water pressure and becomes a pit defect.

The present invention pays attention to this phenomenon, and a method for producing a stainless steel foil having an excellent antiglare property, which effectively reduces the surface gloss only by cold rolling without extremely roughening the surface of the material, and further rolling Rolling method that prevents the occurrence of continuous defects on the surface of the stainless steel foil when foreign matter is mixed between the surface of the rolling roll and the surface of the stainless steel foil, enables stable production, and prolongs the life of the rolling roll. The purpose is to provide.

[0013]

According to the present invention, in a final cold rolling step in which rough rolling, intermediate rolling of 2 passes or more and finish rolling are performed in this order, surface roughness Ra is 0.20 μm or more and 1.20 μm or less. Rough rolling with a rolling reduction of 15% or more and 30% or less is performed using rolls, and subsequently, a rolling reduction of each pass is 5% or more and 15% with a roll having a surface roughness Ra of 0.10 μm or more and less than 0.20 μm. Perform the following intermediate rolling,
Then, the surface roughness Ra is 0.01 μm or more and 0.05 μm or more.
Finish rolling with a rolling reduction of 1% or more and 10% or less is performed using a ceramics roll of m or less. Further, bright annealing is performed subsequent to the finish rolling.

[0014]

The stainless steel foil having excellent anti-glare properties and the method for producing the same according to the present invention can be applied to a stainless steel sheet which has undergone a normal process, in the final cold rolling step, the material of the rolling roll, the roughness of the rolling roll, and the reduction ratio. The feature is that the number of rolling passes is performed within a specific range.

The reasons for limiting the present invention will be described below.

First, the relationship between the antiglare property of the stainless steel foil and the area ratio of the depressions on the surface of the stainless steel foil will be described.

The average roughness of the surface, that is, the smoothness is important as a factor of the antiglare property of the stainless steel foil. Particularly, the foil having a high average surface roughness (Ra) has the exposure test of FIG. As shown in the result (exposed for 1 year at a location 1 km from the coast), it is liable to be soiled and rusted, which is a problem when used for interior / exterior walls, roofs and precision parts.

In order to produce a stainless steel foil having a low average surface roughness (Ra) and a dull gloss (excellent in antiglare property), a fine recess is formed on the surface in the cold rolling process of the stainless steel foil. By distributing and remaining, it is possible to manufacture a stainless steel foil having excellent antiglare properties.

The surface gloss is generally the average surface roughness (R
Depending on a), when a shallow fine recess is formed on the surface of the stainless steel foil, a very dull gloss is obtained despite the low average roughness (Ra).

That is, it is effective to form shallow and fine depressions as oil pits, and the amount thereof can be controlled by the conditions of cold rolling.

Even on a smooth surface with Ra of 0.1 μm or less,
By setting the area ratio of the depressions having a depth of 0.1 μm or more to 5% or more, it is possible to manufacture a stainless steel foil having excellent antiglare properties.

For the measurement of the area ratio of the depression, the depth of 0.
The depression of 1 μm or more is observed with a 200 × optical microscope, and the area ratio thereof is measured.

As shown in FIG. 1, when the area ratio of the depressions is less than 5%, the glossiness is high and the antiglare property is poor. Therefore, the stainless steel foil of the present invention has a depression with a depth of 0.1 μm or more. The area ratio is 5% or more.

Further, the higher the area ratio of the dents, the more excellent the antiglare property is. However, when the area ratio exceeds 50%, the dents are almost leveled and the effect is saturated.

With respect to the adhesion of stains and rust resistance on the surface of the stainless steel foil, the adhesion and rusting of stains are less likely to occur on a smoother surface.

From the exposure test results shown in FIG. 2, in order to obtain a surface having excellent rust resistance, the surface roughness Ra should be 0.1 μm or less.

The basic concept of the cold rolling technique capable of controlling both the surface roughness and the occurrence of depressions is shown below.

The previous history (oil pits, cracks, grain boundary etching defects, grinding marks) of the plate to be subjected to the final cold rolling is erased by rough rolling. Subsequently, in the intermediate rolling, the roll scratches due to the rough rolling are crushed to generate a large number of oil pits. Further, in finish rolling, the surface roughness of the product sheet is adjusted.

When the final cold rolling is performed on the basis of this technical idea, if the surface of the roll in the rough rolling is too low in roughness, the previous history cannot be wiped out, while on the other hand, the roughness is too high. Since it becomes difficult to sufficiently crush the scratches in rolling, Ra must be in the range of 0.20 to 1.20 μm as the roughness of the roll in rough rolling.

Regarding the rolling reduction, the high rolling reduction is easier in rough rolling than in intermediate rolling and finish rolling.
It is necessary to secure a reduction rate of at least 15% or more.

If the amount of reduction in the intermediate rolling or finish rolling, which cannot increase the reduction rate too much, increases, the number of passes increases and the productivity deteriorates.

If the rolling reduction is too large, stable operation cannot be performed due to the capacity of the equipment. Therefore, the rolling reduction of the rough roll rolling is set to 15% or more and 30% or less (FIG. 3).

When rolled under these conditions, the material is hot-rolled and then pickled and descaled, or hot-rolled and then annealed and pickled, or subsequently cold-rolled or further annealed. It is possible to erase the history of the material that has been pickled. In addition, the same effect can be obtained for materials that have been polished or ground.

The purpose of the intermediate rough rolling is to remove the roll scratches generated in the rough rolling and to newly generate oil pits. For this purpose, the conditions of roll roughness, reduction ratio and number of rolling passes are important.

If the roll roughness is low, oil pits are unlikely to occur, and if it is too high, the surface roughness of the product sheet is high.

In order to obtain the target area ratio of the recesses of 5% or more, the roll surface roughness Ra must be 0.10 μm or more.

On the other hand, in order to prevent the surface roughness after intermediate rolling from remaining on the product sheet, the upper limit is Ra of 0.20 μm.
Must be:

Further, the rolling reduction is required to be 5% or more in order to remove the grain of the rough roll, and when it is insufficient, the scratch grain of the rough roll remains and the Ra of the product plate exceeds 0.1 μm.

On the other hand, when rolling at a high reduction ratio, it is difficult to generate sufficient oil pits, so the upper limit was made 15% (FIG. 4).

In order to effectively and stably obtain the antiglare property in the intermediate rolling, it is necessary to carry out rolling in two or more passes.
It was clear from the test result of 1., and the rolling was defined as two passes or more.

In the finish rolling of, the surface roughness of the product plate is Ra.
It is important to adjust the thickness to 0.1 μm or less and not to cause defects in the product plate when foreign matter is mixed.

The present inventor has a ceramic roll (for example, material: Sialon [S], which is generally known to be difficult to plastically deform, for the purpose of preventing defects in the product plate.
l ₃ N ₄ ]) was applied to the mill rolls.

Here, sialon [Sl ₃ N ₄ ] is selected as the material of the ceramics, but the material is not particularly limited and other ceramics rolls can be applied.

As shown in Table 1, since the roll surface of the ceramic roll is harder than that of the high speed roll, the roll is less likely to be damaged and the product surface is less likely to be defective.

When a ceramic roll is used as a rolling roll, the roll roughness Ra must be 0.05 μm or less.

This has a surface roughness R equivalent to that of HSS roll.
In the case of "a", the product plate has a high gloss and it is impossible to manufacture a product having excellent antiglare properties.

On the other hand, the lower limit of the roll roughness is not particularly limited in view of the quality of the product, but a roll having a high smoothness is not preferable in terms of roll manufacturing technology because it is costly.
m.

Rolling with a high reduction rate using a smooth roll causes the oil pits to disappear and the area ratio of the depressions to be less than 5%. When the rolling reduction is less than 1%, the product surface roughness Ra exceeds 0.1 μm. Therefore, the rolling reduction was set to 1% or more and 10% or less (FIGS. 6 and 7).

A stainless steel foil excellent in antiglare property can be obtained even when the stainless steel foil manufactured in the above steps is subjected to bright annealing without generation of oxide scale.

[0050]

[Examples] Table 2 shows examples of the present invention, comparative examples, conventional examples and evaluation results. SUS304 is used as the steel type, and the conditions for the final rolling of the final cold rolling are shown. The cold rolling test was carried out using a 12-high cluster roll mill.

Final cold rolling was performed under the conditions shown in Table 2 in the order of rough rolling, intermediate rolling of two passes or more, and finish rolling, and the surface roughness (Ra) and surface gloss of the rolled material were evaluated.

The invention examples (No. 1 to No. 6) have surface roughness Ra ≦ 0.1 μm and surface gloss ≦ 600%, and are stainless steel foils excellent in antiglare property.

In Comparative Examples (No. 7 to No. 16), the surface roughness (Ra) was obtained by rolling under the conditions shown in Table 2 such as roll surface roughness, rolling reduction and number of rolling passes. Alternatively, the surface gloss is not satisfactory.

Compared with the conventional example, the surface evaluation of the rolled material is equivalent, but the present invention is excellent in that the life of the rolling roll is dramatically improved.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

[Table 5]

[0060]

As is clear from the above, according to the present invention, it becomes possible to manufacture an antiglare stainless steel sheet having excellent surface properties, and it is difficult for defects to occur in the rolling rolls, so that stable manufacturing is possible. By being able to establish it, it can be expected to greatly improve productivity.

Further, the cost merit can be expected due to the extension of the life of the rolling roll.

[Brief description of drawings]

FIG. 1 is a diagram showing an influence of an area ratio of dents on a plate surface, which affects a glossiness (45 °) of a stainless steel plate.

FIG. 2 is a diagram showing the influence of the plate surface roughness on the rust resistance of a stainless steel plate.

FIG. 3 is a diagram showing an appropriate range of roll roughness and reduction ratio in rough rolling in the final cold rolling step.

FIG. 4 is a diagram showing appropriate roll roughness and reduction ratio ranges in intermediate rolling in the final cold rolling step.

FIG. 5 is a diagram showing the required number of rolling passes in intermediate rolling in the final cold rolling step.

FIG. 6 is a diagram showing appropriate ranges of roll roughness and reduction in finish rolling in the final cold rolling step.

FIG. 7 is a diagram showing the influence of ceramic roll roughness on the glossiness (45 °) of a stainless steel plate in finish rolling in the final cold rolling step.

FIG. 8 is a diagram showing roll life depending on roll material in finish rolling in the final cold rolling step.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Ikemoto 3434 Shimada, Hitsu-shi, Nippon Steel Corporation Stock of the Nippon Steel Corporation (72) Inventor Hidetoshi Anbu 3434, Shimada, Nippon Steel Stock Association of Nippon Steel Inside the Shoko Steel Works (72) Inventor Takemi Funai 3434 Shimada, Shinjuku City Shin Nippon Steel Co., Ltd. Inside the Shoko Steel Works (72) Inventor Hiromitsu Yamamoto 3434 Shimada, Shinjuku Nippon Steel Co., Ltd. Inside the Hikari Steel Works (72) Inventor Michiharu Iwamoto 3434 Shimada, Oita City Shin-Nippon Steel Co., Ltd. Inside the Hikari Steel Works (72) Toshiaki Hashimoto 3434 Shimada, Shinjuku Nippon Steel Co., Ltd. Inside the steelworks (72) Inventor Kokusatsu, 3434 Shimada, Omitsu City, Shinjuku Shin Nippon Steel Co., Ltd. Inside the Komitsu Steel Works (72) Inventor, Shizuhiko Murata, 3434 Shimada, Hikari City, Shin Nippon Steel Inside the Ironworks (72) Inventor Jun Araki light City Oaza Shimada 3434 address Nippon Steel stock company in Hikariseitetsusho

Claims (2)

[Claims] 1. In a final cold rolling step in which rough rolling, intermediate rolling of two or more passes and finish rolling are performed in this order, a roll having a surface roughness Ra of 0.20 μm or more and 1.20 μm or less and a reduction ratio of 15 is used. % Or more and 30% or less, and then the surface roughness Ra is 0.10 μm or more and 0.2 or more.
Intermediate rolling with a rolling reduction of 5% or more and 15% or less in each pass is performed using a roll of less than 0 μm, and then the surface roughness Ra
A method for producing a stainless steel foil having excellent antiglare properties, which comprises performing finish rolling with a rolling reduction of 1% or more and 10% or less using a ceramic roll having a thickness of 0.01 μm or more and 0.05 μm or less. 2. The method for producing a stainless steel foil having excellent antiglare properties according to claim 1, wherein bright annealing is performed subsequent to the finish rolling.