JP2655989B2 - Cold rolling method for ultra-thin metal materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold rolling method for an ultra-thin metal material such as a foil strip, and more particularly to a cold rolling method in which a cold-rolled metal material is secondarily rolled.

[0002]

2. Description of the Related Art When an ultra-thin metal material such as a foil strip is manufactured by cold rolling, a metal material that has been subjected to normal cold rolling is once cooled by a tandem cold rolling method in which a plurality of rolling mill stands are provided in series. The secondary rolling is performed by a cold rolling mill, and it is usual to perform cold rolling to reduce the thickness of the sheet at the preceding stage and temper rolling to improve the shape and mechanical properties at the subsequent stage. .

[0003] The ultra-thin metal material, which is a product, is generally defined in terms of sheet surface roughness, and it is usual to perform temper rolling in a final stand using a work roll having a roll roughness corresponding to the sheet surface roughness. However, when the sheet thickness is small and the roll roughness is high, the material may buckle due to the compressive stress in the sheet width direction, and a shape defect called a vertical streak may occur.
Conventionally, when a vertical streak is generated and hinders the operation, it is sent to a tension leveler which is a separate process, and an operation of removing the same is performed.

[0004] However, such a method requires a separate step only for removing the vertical streaks, which naturally causes inconveniences such as a decrease in yield, an increase in the number of lateral holdings, and occurrence of a process wait.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above problems and to provide a rolling method that does not generate vertical streaks, thereby eliminating the need for a separate process.

[0006]

SUMMARY OF THE INVENTION According to the present invention, cold rolling is performed at a front stage of a plurality of rolling mill stands provided in series.
In a tandem cold rolling mill for ultra-thin metal material which performs temper rolling in a latter part, ultra-thin metal characterized in that the latter part is temper-rolled by a work roll having a roll roughness suitable for the sheet thickness. This is a cold rolling method for a material.

[0007] Alternatively, the present invention relates to a tandem cold rolling mill for ultra-thin metal materials, wherein cold rolling is performed at a front stage of a plurality of rolling mill stands provided in series and temper rolling is performed at a rear stage. The cold rolling of the former part is performed by a work roll having a roll roughness corresponding to the sheet surface roughness required for a product, and the temper rolling of the latter part is performed by a work roll having a roll roughness suitable for the sheet thickness. This is a cold rolling method for an ultra-thin metal material.

[0008]

[Operation] As described above, the occurrence of vertical streaks is closely related to the sheet thickness and the roll roughness in temper rolling. Based on this finding, the present inventors first obtained, by experiment, a vertical streak, that is, a limit value of roll roughness that does not cause buckling, for each plate thickness of the ultrathin metal material. The results are shown in FIG. The material is steel foil,
The rolling load per material width was fixed at 250 kg / mm.

The curve indicates the critical roll roughness that does not cause buckling with respect to the sheet thickness, and the roll roughness may be any value less than this. Therefore, in the temper rolling of the latter part, the roll roughness suitable for the sheet thickness is selected according to these conditions. By the way, generation of vertical streaks can be prevented by this alone, but there are cases where the plate surface roughness required for the product cannot be satisfied. Therefore, in such a case, a predetermined roughness is imparted to the sheet surface by cold rolling of the former stage portion.

In the cold rolling stage, since the rolling reduction is large, there is no displacement in the width direction of the material to be rolled, and buckling does not occur irrespective of the roll roughness. Also, even if buckling occurs in the scale, it is corrected by the subsequent temper rolling, so that no vertical streaks remain in the product.

[0011]

【Example】

Example 1 The present invention was applied to the secondary cold rolling of a steel foil (steel foil) having a thickness of 60 μm. As shown in Fig. 1 above, the limit of the roll roughness that conforms to this sheet thickness, that is, the limit value of the temper rolling roll roughness that does not cause buckling for this sheet thickness is 0.25 μm.
m. The required surface roughness (Ra) is 0.20 to
0.30 μm.

The two-stand tandem rolling mill had a roll roughness (Ra, hereinafter the same) of 0.25 μm for both the first and second temper rolling stands, but no vertical streaks were generated. The surface roughness was 0.22 μm, which was within the specified range. As a comparative example, the roll roughness of the rolling stand was 0.08 μm, and the roll roughness of the temper rolling stand was
When the same material was subjected to secondary rolling at 1.10 μm, a fairly clear vertical streak with a peak height of 20 to 30 μm was generated. However, the surface roughness was 0.28 μm, which was within the predetermined range.

As another comparative example, the same material was subjected to secondary rolling with the roll roughness of the rolling stand being 0.08 μm and the roll roughness of the temper rolling stand being 0.25 μm. However, the surface roughness is 0.17 μm
Out of the predetermined range. Example 2 The present invention was applied to the second cold rolling of an extremely thin steel sheet having a thickness of 100 μm. The required surface roughness (Ra) is 0.20 to 0.30 µm.

By a two-stand tandem rolling mill, a roll having a roll roughness (Ra) of 0.25 μm is used for the first-stage rolling stand, and a roll roughness (Ra) is used for the second-stage temper rolling stand.
When a sample having a thickness of 0.08 μm was used, no vertical streaks were generated, and the plate surface roughness was within a predetermined range.

[0015]

According to the present invention, no vertical streaks are generated in the secondary rolling process and a desired plate surface roughness can be realized, so that a separate process is not required, and the production efficiency of an extremely thin material is reduced. It has an excellent effect of improving the yield.

[Brief description of the drawings]

FIG. 1 is a graph showing buckling occurrence conditions according to the present invention.

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Claims (2)

(57) [Claims] 1. A tandem type cold rolling mill for ultra-thin metal, wherein cold rolling is performed at a front stage of a plurality of rolling mill stands provided in series and temper rolling is performed at a rear stage thereof, and is adapted to a sheet thickness. A cold rolling method for an ultra-thin metal material, wherein the temper rolling of a subsequent stage portion is performed by a work roll having a roll roughness. 2. A tandem-type cold rolling mill for ultra-thin metal materials, in which cold rolling is performed at a front stage of a plurality of rolling mill stands provided in series and temper rolling is performed at a rear stage thereof, which are required for products. Cold rolling of the former part by a work roll having a roll roughness corresponding to the sheet surface roughness, and temper rolling of the latter part by a work roll having a roll roughness suitable for the sheet thickness. Cold rolling method for ultra-thin metal materials.