JP3274295B2 - Method for producing stainless steel foil with excellent anti-glare properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stably 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 anti-glare properties, a method of cold rolling using a roll having a rough surface to roughen the surface of the stainless steel sheet, or after or after cold rolling. A method of roughening the surface of a stainless steel plate by performing electrolytic rolling or immersion in an aqueous solution containing nitric acid or hydrofluoric acid for pickling after cold rolling and annealing is used.

As an example of the above-mentioned method, a technique of imparting antiglare properties by performing pickling on a stainless steel sheet whose surface has been roughened by cold rolling, for example, as disclosed in JP-A-5-163528, Surface roughness (Ra) of 0.5 to 10.
There is a pickling method in which a cold-rolled stainless steel sheet of 0 μm is brightly annealed and finally immersed in a mixed acid of nitric acid and hydrofluoric acid.

However, in this method, since the surface of the stainless steel sheet is significantly roughened by cold rolling or pickling, the surface is apt to be stained with dust or the like, impairing the appearance of the surface and deteriorating the corrosion resistance. Further, the acid used for pickling is difficult to handle, which is not preferable in terms of environmental hygiene.

However, in the prior art, no method of imparting anti-glare properties has been proposed other than a cold rolling method or a method of performing pickling treatment that remarkably roughens the surface, and a stainless steel excellent in satisfactory anti-glare properties has not been proposed. There was no stable production method for steel sheets.

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

[0007] When foreign matter is mixed between the surface of the rolling roll and the stainless steel plate during rolling, the rolling roll undergoes plastic deformation, causing continuous defects on the surface of the stainless steel plate.

Further, since a large-diameter roll is used at the time of finish rolling, the possibility of occurrence of defects increases with an increase in penetration of lubricating oil.

This is because a large amount of lubricating oil infiltrates increases the possibility of foreign matter entering.

[0010]

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

This is because when a large amount of lubricating oil enters 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-like defect.

The present invention pays attention to this phenomenon, and a method for producing a stainless steel foil excellent in anti-glare properties, in which the surface gloss is effectively reduced only by cold rolling without extremely roughening the material surface. Rolling method to prevent the occurrence of continuous defects on the stainless steel foil surface when foreign matter is mixed between the roll surface and the stainless steel foil surface during rolling, and to achieve stable production and extend the life of the roll. The purpose is to provide.

[0013]

According to the present invention, in a final cold rolling step of rolling in the order of rough rolling, two or more passes of intermediate rolling and finish rolling, the surface roughness Ra is 0.20 μm to 1.20 μm. Rough rolling is performed using a roll with a reduction ratio of 15% or more and 30% or less, and subsequently, a reduction ratio of each pass is 5% or more and 15% using a roll having a surface roughness Ra of 0.10 μm or more and less than 0.20 μm. Perform the following intermediate rolling,
Subsequently, the surface roughness Ra is 0.01 μm or more and 0.05 μm.
The finish rolling is performed using a ceramics roll of m or less with a draft of 1% or more and 10% or less. Bright annealing is performed subsequent to the finish rolling.

[0014]

According to the present invention, a stainless steel foil having excellent anti-glare properties and a method for producing the same are obtained by subjecting a stainless steel sheet which has undergone a normal process to a rolling roll material, a rolling roll roughness, and a rolling reduction in a final cold rolling step. The number of rolling passes is set 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 depression 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. In particular, a foil having a high average surface roughness (Ra) is shown in FIG. As shown in the results (exposed for 1 year at a place 1 km from the coast), dirt and rust easily occur, which is a problem when used for interior and exterior walls, roofs and precision parts.

In order to produce a stainless steel foil having a low average surface roughness (Ra) and a low gloss (excellent in antiglare properties), fine depressions are formed on the surface during the cold rolling step of the stainless steel foil. By distributing and remaining, a stainless steel foil excellent in anti-glare properties can be manufactured.

The surface gloss is generally determined by the average surface roughness (R
Although depending on a), when a shallow and fine depression is formed on the surface of the stainless steel foil, a very dull luster is obtained despite the low average roughness (Ra).

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

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

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

As shown in FIG. 1, when the area ratio of the depression is less than 5%, the glossiness is increased and the antiglare property is deteriorated, so that the stainless steel foil of the present invention has a depression having a depth of 0.1 μm or more. The area ratio is set to 5% or more.

The higher the area ratio of the depression, the better the anti-glare property. However, if it exceeds 50%, the anti-glare property is almost flat and the effect is saturated.

Further, with respect to the adhesion and rust resistance of stains on the surface of the stainless steel foil, the smoother the surface, the less the stains and rust.

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

The basic concept of the cold rolling technique capable of controlling both the surface roughness and the occurrence of pits will be described below.

The pre-history (oil pits, cracks, grain boundary etching defects, and remaining grinding marks) of the plate to be subjected to final cold rolling is eliminated by rough rolling. Subsequently, in the intermediate rolling, the roll scratches formed by 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 based on this technical idea, the surface of the roll in the rough rolling cannot be wiped off if the roughness is too low, while the surface is too high. Since it becomes difficult to sufficiently crush the scratches in the rolling, the roughness of the roll in the rough rolling must be Ra in the range of 0.20 to 1.20 μm.

Further, with regard to the rolling reduction, the rough rolling is easier to obtain the high rolling reduction than the intermediate rolling and the finish rolling.
It is necessary to secure a rolling reduction of at least 15% or more.

When the rolling reduction in the intermediate rolling and the finish rolling, in which the rolling reduction is not so high, is increased, the number of passes is increased and the productivity is deteriorated.

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 was set to 15% or more and 30% or less (FIG. 3).

When rolling is performed under these conditions, a material that has been subjected to hot rolling and then subjected to pickling descaling, a material that has been subjected to hot rolling and annealing and pickling, or a material that has been subsequently subjected to cold rolling and further annealed. It is possible to wipe out the history of the material that has been pickled. In addition, it has the same effect on polished and ground materials.

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

If the roll roughness is low, oil pits are less likely to occur, and if it is too high, the surface roughness of the product plate increases.

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

On the other hand, in order to prevent the surface roughness after the 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 coarse rolls. If the rolling reduction is insufficient, the scratches of the coarse rolls remain and the Ra of the product plate exceeds 0.1 μm.

On the other hand, when rolling at a high rolling reduction, sufficient oil pits hardly occur, so the upper limit was set to 15% (FIG. 4).

FIG. 5 shows that in order to effectively and stably obtain the antiglare property in the intermediate rolling, it is necessary to perform two or more passes of rolling.
And the rolling was determined to be two or more passes.

In the finish rolling, the surface roughness of the product plate is adjusted to Ra.
It is important that the thickness be adjusted to 0.1 μm or less and that no defects occur on the product plate when foreign matter is mixed.

The inventor of the present invention has proposed a ceramic roll (for example, material: Sialon [S], which is generally known to be hardly plastically deformed, in order to prevent defects from occurring on the product plate.
l ₃ N ₄ ]) was applied to the rolling rolls.

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

As shown in Table 1, since the surface of the ceramic roll is harder than that of the high-speed roll, the roll hardly suffers from defects and the product surface hardly suffers from defects.

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

This is because the surface roughness R is equivalent to that of the high-speed roll.
In the case of a, the gloss of the product plate becomes high, and it is impossible to produce a product having excellent anti-glare properties.

On the other hand, the lower limit of the roll roughness is not particularly limited in terms of the quality of the product.
m.

When rolling is performed at a high rolling reduction with a smooth roll, oil pits disappear and the area ratio of the pit becomes less than 5%. When the rolling reduction is less than 1%, the product surface roughness Ra exceeds 0.1 μm. Therefore, the rolling reduction is set to 1% or more and 10% or less (FIGS. 6 and 7).

Even when the stainless steel foil produced in the above step is subjected to bright annealing in which no oxide scale is generated, a stainless steel foil having excellent antiglare properties can be obtained.

[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 of the finish rolling in the final cold rolling are shown. In addition, this cold rolling test was performed using a 12-stage cluster roll rolling mill.

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

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

In the comparative examples (No. 7 to No. 16), the rolling was performed under the conditions shown in Table 2 such as the roll surface roughness, the rolling reduction, and the number of rolling passes. As a result, the surface roughness (Ra) was obtained. Alternatively, the surface gloss is not satisfactory.

As compared with the conventional example, the surface evaluation of the rolled material is the same, but the present invention is superior 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 evident from the above, according to the present invention, it is possible to produce an antiglare stainless steel sheet having excellent surface properties, and it is difficult to generate defects in the rolling rolls. By being able to establish, significant improvement in productivity can be expected.

Further, a cost advantage can be expected because the life of the rolling roll can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram showing the effect of the area ratio of a dent on the plate surface on the glossiness (45 °) of a stainless steel plate.

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

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

FIG. 4 is a diagram showing a range of appropriate roll roughness and rolling reduction in intermediate rolling in a 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 an appropriate range of roll roughness and rolling reduction in finish rolling in a final cold rolling step.

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

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

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Ikemoto 3434 Shimada, Hikari-shi, Nippon Steel Corporation Inside the Hikari Works (72) Inventor Hidetoshi Yasutake 3434 Shimada, Hikari, Hikari-shi Nippon Steel Corporation Hikari Inside the steelworks (72) Inventor Takeshima Funai 3434 Shimada, Hikari-shi, Nippon Steel Corporation Inside the Hikari Works (72) Inventor Hiroshi Yamamoto 3434, Shimada, Oaza, Hikari-shi Nippon Steel Corporation Inside the Hikari Works (72) Inventor Michiharu Iwamoto 3434 Shimada, Hikari-shi Nippon Steel Corporation Hikari Works (72) Inventor Toshiaki Hashimoto 3434 Shimada, Hikari-shi Nikko Steel Corporation Hikari Works (72) Inventor: 3434 Shimada, Oaza, Nippon Steel Corporation Nippon Steel Corporation (72) Inventor: Shizuhiko Murata 3434, Shimada, Oji, Hikari City Nippon Steel Corporation: Nippon Steel Corporation (72) Inventor Jun Araki 3434 Shimada, Omitsu City Nippon Steel Corporation Hikari Works (56) References JP-A-1-197003 (JP, A) JP-A-61-49705 (JP, A) JP-A-59-56901 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1/00-3/02 C21D 9/46 C22C 38/00

Claims (2)

(57) [Claims] 1. In a final cold rolling step of rolling in the order of rough rolling, intermediate rolling of two or more passes, and finish rolling, a roll having a surface roughness Ra of not less than 0.20 μm and not more than 1.20 μm has a draft of 15%. % Or more and 30% or less, followed by surface roughness Ra of 0.10 μm or more and 0.2% or less.
Using a roll of less than 0 μm, intermediate rolling is performed in which the rolling reduction of each pass is 5% or more and 15% or less, followed by surface roughness Ra.
A method for producing a stainless steel foil having excellent anti-glare properties, comprising 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.