JPH05115902A - Method for cold rolling shutter material for disk cassette - Google Patents

Abstract

(57) [Summary] [Purpose] Warpage occurs when rolled by a rolling roll having both surfaces of a steel strip used for a shutter material for a disc cassette and a surface different from that of the steel strip. This warp is corrected without adding a leveling process or the like. [Structure] A rolled steel strip 9 having one surface rolled with a dull roll 1 and the other surface rolled with a grindstone polishing roll 2 is kept at a winding tension of 60 to 80% of the yield stress of the material and a diameter of 60 to 20.
The 0 mmφ straightening roll 10 is pressed against the surface of the dull roll to suppress warpage of the steel strip 9 in the rolling direction and the width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a pair of upper and lower work rolls having different surfaces to cold-roll a shutter material for a disc cassette, and warps the steel strip in the rolling direction and the plate width direction. The present invention relates to a cold rolling method for suppressing the above.

[0002]

2. Description of the Related Art As a shutter material for a disc cassette, a stainless metal material has been widely used so far. The stainless steel shutter material has the advantage that dust due to static electricity does not adhere to the magnetic medium and has excellent heat resistance, but on the other hand, there is a concern that the cassette body made of resin may be scraped off by repeated opening and closing of the shutter.

In order to prevent this, it is effective to roll the surface (rear surface) on the side in contact with the cassette body with a grindstone polishing roll parallel to the shutter opening / closing direction, and roll the opposite surface (front surface) on the dull roll. . However, in ordinary cold rolling, if the working method of the work roll surfaces used on the front and back surfaces is changed as described above, the steel strip after rolling exhibits a convex shape on the side where the dull roll is used, and so-called warpage occurs.

Shutter materials for disk cassettes are generally required to have a warp of 100 mm / 1 m or less in the rolling direction, and a leveling step after rolling is added.
In reality, there is no choice but to add a process for reducing warpage.

[0005]

The above-mentioned means for imparting the leveling process has a problem in that the cost is increased due to the addition of the process and the possibility of occurrence of a flaw is increased. It is an object of the present invention to provide a cold rolling method for a shutter material for a disc cassette which solves the above problems.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, when manufacturing a shutter material for a disc cassette in which one side of a steel strip is rolled by a dull roll and the other side is rolled by a grindstone polishing roll, the winding tension of the rolled steel strip is set at the yield of the material. The stress is kept at 60 to 90%, and the diameter of the steel strip is 60 mmφ or more 2
A method for cold rolling a shutter material for a disc cassette, which comprises pressing a straightening roll having a diameter of 00 mm or less to suppress warpage of a steel strip.

[0007]

According to the present invention, the straightening roll installed between the work roll of the rolling mill and the winder for winding the rolled steel strip has a winding tension of 60 to 90 which is the yield stress of the material. %
Under the conditions described above, the warp can be corrected by pressing the steel strip from the plate surface on the dull roll-rolled side. The pressing of the straightening roll from the surface of the dull roll is because, when the dull roll is used on one side and the work roll which is grindstone-polished on the other side, the warp of the steel strip is convex on the dull roll-rolled side. .

The reason why the diameter of the straightening roll is set to 200 mmφ or less is that when the roll diameter exceeds 200 mmφ, the desired warp straightening effect may not be obtained. Further, a straightening roll having a diameter of less than 60 mmφ cannot be applied because the roll is damaged due to insufficient strength during use. The take-up tension of the steel strip pressed against the straightening roll is set to 6
0 to 90% is because the winding tension is 6 of the material yield stress.
If it is less than 0%, the minimum straightening roll diameter 6 to which the present invention can be applied is 6
Even after using a 0 mmφ roll, 1 per 1 m after straightening
This is because the warp exceeding 00 mm remains. Further, when the winding tension exceeds 90% of the material yield stress, problems such as plate breakage frequently occur and rolling cannot be performed.

FIG. 3 shows the relationship between the straightening roll diameter and the proper winding tension. The hatched area in the figure is the proper range. In this proper range, the straightening roll diameter is 60 to 20.
The winding tension / material yield stress ratio is distributed between 60% and 90% over the range of 0 mmφ.

[0010]

FIG. 1 shows an example of installing a straightening roll for straightening a warp according to the present invention. The steel strip 9 drawn out from the rewinding machine 6 has its course adjusted by a deflecting roll 4, moves in a rolling direction 11, and is rolled by a rolling machine composed of an upper dull roll 1 and a lower grindstone polishing roll 2 to form a deflecting roll. It is taken up by the winder 5 after passing through 3. Plate thickness gauges 7 and 8 are provided on the outgoing side and the incoming side of the rolling mill. The straightening roll 10 between the winder 5 and the deflecting roll 3 was arranged so as to push the surface of the upper dull roll 1 side. In this embodiment, since the dull roll is used as the upper work roll 1 of the rolling mill and the grinding stone polishing roll is used as the lower work roll 2, the straightening roll 10 for straightening the warp is installed so as to be pressed from the upper side of the steel strip 9. There is. If the relationship between the upper and lower work rolls is reversed, the straightening roll 10 may have a structure of pressing from the lower side of the steel strip 9. Further, the installation place is also between the deflector roll 3 and the winder 5 in this embodiment, but the same effect can be obtained even if it is installed between the work rolls 1 and 2 and the deflector roll 3. .

FIG. 2 shows an example of the effect of correcting the warp amount according to this embodiment. Correcting roll radius R (m
m), the abscissa axis represents the t / R ratio, and the ordinate axis represents the warp amount, and the winding tension is shown as a parameter. If the winding tension is 90% of the material yield stress, the diameter of the straightening roll is 200 m
Even with mφ, the warpage after straightening is a sufficient standard (1 warpage per 1 m
00 mm or less) is satisfied. Even if the winding tension is reduced to 75% of the material yield stress, the diameter of the straightening roll may be 110 mmφ or less. Further, the winding tension is 6 of the material yield stress.
When it is 0%, the diameter of the straightening roll is 60 mmφ.

[0012]

EFFECTS OF THE INVENTION According to the present invention, the leveling step or the like can be applied to the large warpage that occurs when the front and back surfaces of a steel strip are rolled with a shot dull roll on one side and a grindstone polishing roll on the other side. It became possible to straighten and roll without doing. With this technique, it is possible to manufacture a shutter material for a disc cassette, which is excellent in preventing dust generation.

[Brief description of drawings]

FIG. 1 is a side view showing an installation example of a warp correction roll according to the present invention.

FIG. 2 is a graph showing an effect of improving a warp amount by a straightening roll.

FIG. 3 is a graph showing a relationship between a straightening roll diameter and an appropriate winding tension.

[Explanation of symbols]

 1 Upper work roll (dull roll) 2 Lower work roll (grinding stone polishing roll) 3 Deflect roll 4 Deflect roll 5 Winder 6 Rewinder 7 and 8 Plate thickness gauge 9 Steel strip 10 Warp straightening roll 11 Rolling direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B21D 1/02 K 9043-4E G11B 23/03 J 7201-5D

Claims (1)

[Claims] 1. When manufacturing a shutter material for a disk cassette in which one side of a steel strip is rolled with a dull roll and the other side with a grindstone polishing roll, the winding tension of the rolled steel strip is kept at 60 to 90% of the yield stress of the material. A method for cold rolling a shutter material for a disc cassette, which comprises pressing a straightening roll having a diameter of 60 mmφ or more and 200 mmφ or less against the plate surface side of the steel strip rolled by the dull roll to suppress warpage occurring in the steel strip.