JP3690357B2 - Work roll for metal foil rolling - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal foil rolling work roll used for cold rolling of a metal foil.
[0002]
[Prior art]
When the material to be rolled is rolled by a rolling mill, the work roll undergoes elastic deformation due to roll flatness and roll axis deflection. FIG. 6 is a schematic diagram for explaining the elastic deformation of the work roll 10. In FIG. 6, the symbol W is the sheet width of the material to be rolled (metal foil), and 1a 'is the roll axis during cold rolling. The core position, 1b ′, is the surface shape of the roll body during cold rolling. 1a is the roll axis before cold rolling, and 1b is the roll body surface shape during cold rolling when there is no roll flat deformation. A reel (winding / rewinding device) (not shown) is arranged on the entry side and the exit side of the rolling material conveyance direction with respect to the rolling mill, and the material to be rolled is unwound from one of the reels and wound on another reel. Rolling that repeats the operation of rolling the entire length of the material to be rolled in the opposite direction by rolling the reel on the take-up side and the reel on the unwinding side on its own after rolling the entire length of the material to be rolled in one direction on a rolling mill. 5 is a type that performs reverse rolling, but the rolling mill here is not shown, but is a rolling machine in which one metal foil is arranged in a plurality of tandems. Includes those that are rolled at the same time. In any of the rolling mills, rolling to a final finished thickness desired by cold rolling of the metal foil is performed a plurality of times (pass).
[0003]
In the cold rolling of metal foil, when the plate thickness is reduced, the work rolls 1 may contact each other (hereinafter referred to as roll kiss) at the roll barrel end as shown in FIG. In particular, when the deformation resistance of the material to be rolled S is large as in the case of cold rolling of stainless steel foil, the elastic deformation of the work roll 1 described above increases. Roll kiss may occur at a part of the roll barrel end from the stage where the metal foil is still thicker than the final finished thickness.
[0004]
In FIG. 7, 1C is a portion where roll kisses are generated at the end of the roll body.
When the metal foil is cold-rolled in such a state where roll kisses are generated, cracks are generated from the portion 1C where the roll kisses occurred while the rolling distance is still short. There is a problem that polling, roll breakage, etc. occur, and there is a problem that a plate breakage trouble occurs.
[0005]
Here, as a cause of the occurrence of cracks at the end of the roll cylinder where the roll kiss has occurred, the temperature is higher than the center of the roll cylinder in contact with the material to be rolled S, and the central part of the roll cylinder in contact with the material to be rolled S. It is conceivable that the shearing force becomes large. Since the center portion of the roll cylinder is in contact with the material to be rolled S and is cooled by the material to be rolled S, the end portion of the roll cylinder is not in contact with the material to be rolled S, so that the frictional heat generated by the roll kiss is accumulated. This is the reason for the high temperature. In addition, when there is a difference in diameter between the upper and lower work rolls 10, a greater shearing force acts on the portion 1C where the roll kiss has occurred, and cracks are more likely to occur from this portion.
[0006]
Therefore, for example, a work roll 10 for metal foil intended to prevent roll kiss as shown in FIG. 8 is disclosed in Japanese Patent Laid-Open No. 10-156405.
According to the technique disclosed in Japanese Patent Application Laid-Open No. 10-156405, by rolling using a work roll 10 in which a step is provided between the roll cylinder center part 2 and the roll cylinder end part 3, roll kiss during rolling can be obtained. I try to prevent it. However, if the distance from the plate width end to the stepped portion, that is, the roll barrel end 3 where the diameter starts to decrease, that is, the margin E in FIG. There is a problem that there are many troubles that the material to be rolled S breaks during cold rolling of the metal foil. Further, in the work roll 10, when the margin E is sufficiently large, the effect of preventing the roll kiss is insufficient, and there is a disadvantage that a crack is generated from the portion 1C where the roll kiss occurs.
[0007]
[Problems to be solved by the invention]
The present invention aims to eliminate the above-mentioned problems of the prior art, and long distance rolling without causing cracks at the end of the roll cylinder even when cold rolling of the metal foil is performed under the circumstances where roll kiss occurs. An object of the present invention is to provide a work roll for metal foil rolling that can stably cold-roll metal foils even if there is fluctuations in the width of the material to be rolled or meandering of the material to be rolled. And
[0008]
[Means for Solving the Problems]
Knowledge that the present invention can solve the above-mentioned problems by providing a difference in hardness between the roll cylinder center part and the roll cylinder end part without providing a step between the roll cylinder center part and the roll cylinder end part. It was completed based on.
The present invention is as follows.
1. The roll body is made of steel, and the hardness of the center of the roll body in contact with the material to be rolled is HRC: 63 to 73, and the hardness of the roll body ends on both sides thereof is HRC: 53 to 58, and A work roll for rolling metal foil, wherein the difference in hardness between the center of the roll cylinder and the end of the roll cylinder is greater than 5 and less than 20 in HRC.
2. The difference in hardness between the roll cylinder center and the roll cylinder end is 10 to 15 in terms of HRC. The work roll for metal foil rolling described in 1.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The work roll for rolling metal foil according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b).
Fig.1 (a) is a schematic diagram of the roll trunk | drum of the work roll 1 for metal foil rolling which concerns on this invention (henceforth only a work roll 1), and the code | symbol D is a roll trunk | drum length in the figure. , A is the length of the center portion of the roll cylinder, and B and C are the lengths of the left and right roll cylinder ends in the figure. Moreover, FIG.1 (b) is a schematic diagram of the roll kiss state at the time of rolling the to-be-rolled material S of the board width W using the work roll 1. FIG.
[0010]
The work roll 1 according to the present invention is not provided with a step between the roll cylinder central part 2 and the roll cylinder end part 3. The roll drum central portion 2 is a portion that contacts the material to be rolled S, and the roll drum end portions 3 on both sides thereof may be in contact with each other, that is, roll kissed, when the metal foil is cold-rolled. The roll body of the work roll 1 is made of steel, and can be, for example, cold die steel, high speed steel or the like.
[0011]
As for the work roll 1 which concerns on this invention, the hardness of the roll cylinder center part which contacts a to-be-rolled material is HRC: 63-73, and the hardness of the roll cylinder edge part of the both sides is HRC: 53-58. Here, HRC is in accordance with JIS Z2245.
In the work roll 1 according to the present invention, the reason why the hardness of the central portion of the roll cylinder is limited to HRC: 63 to 73 is that when the hardness of the central portion of the roll cylinder is less than HRC: 63, the roll wear is fast and the roll is rolled. When the hardness of the center part of the roll cylinder exceeds HRC: 73, there arises an inconvenience of inferior accident resistance such as easy cracking even if roll kiss does not occur. For this reason, in the present invention, the hardness of the central portion of the roll cylinder is limited to HRC: 63 to 73.
[0012]
Moreover, in the work roll 1 which concerns on this invention, the hardness of the roll trunk | drum edge part 3 of both sides is made lower than the hardness of the roll trunk | drum center part 2. FIG. The reason for doing this is that by reducing the hardness of the body portion of the work roll 1, the toughness is increased and the crack resistance can be improved. For example, FIG. 2 is a graph showing the relationship between hardness and absorbed energy of a test material whose steel type is high-speed steel. From this result, it is understood that when the body portion of the work roll 1 is made of high speed steel, the toughness (Charpy absorbed energy) is increased and the crack resistance is improved by reducing the hardness.
[0013]
Further, when the body portion of the work roll 1 is made of high speed steel, the effect of improving crack resistance is saturated even if the hardness of the roll barrel end portions 3 on both sides is less than HRC: 53. When the hardness of the end portion is set to HRC: 53 or more and the hardness of the roll barrel end portions 3 on both sides is set to exceed HRC: 58, crack resistance becomes insufficient. The hardness is set to HRC: 58 or less.
[0014]
Furthermore, in the work roll 1 according to the present invention, the reason why the difference in hardness between the roll cylinder central portion 2 and the roll cylinder end 3 exceeds 5 and is less than 20 is as follows. .
When the difference in hardness between the roll cylinder center part 2 and the roll cylinder end part 3 is 5 or less in terms of HRC, when the metal foil is cold-rolled, a conventional work in which the roll cylinder part has a HRC value of 5 or less is not required. Compared with the roll, no difference was found in the rolling distance until cracks occurred in the portion 1C where the roll kiss occurred, while the difference in hardness between the roll barrel end and the roll barrel center was 20 in HRC. Exceeding the above range, there is a disadvantage that a shape defect is likely to occur during cold rolling of the metal foil, and the metal structure of the roll is thermally distorted due to hardness tempering by heat treatment during the production of the work roll 1. Inconveniently, the work roll 1 is likely to break. For this reason, in this invention, the difference of the hardness of the roll trunk | drum center part 2 and the roll trunk | drum edge part 3 was limited to less than 20, exceeding 5 in HRC.
[0015]
Moreover, the work roll 1 according to the present invention, when the plate width W of the rolled material to be rolled is not constant, the same as the sheet width W _A of more material to be rolled most rolling frequently the length A of the roll body central portion it may be fabricated to have, or may be equal to the widest plate width W _a of the material to be rolled. .
Using such work roll 1, when to perform cold rolling of a metal foil, and when the rolling material to be rolled wide strip width W _B than the plate width W _A, the rolled material in the plate width W _A When rolling the sheet, when the sheet width fluctuation or meandering occurs, the sheet width end portion of the material S to be rolled out outside the roll body center part 2 comes into contact with the roll body end part 3. Moreover, since there is no level | step difference between the roll cylinder center part 2 and the roll cylinder edge part 3, a plate fracture | rupture trouble can be prevented.
[0016]
【Example】
A plurality of pairs of steel work rolls having a diameter of 40 mm and a roll body length D of 1300 mm are manufactured, one pair at a time is assembled in the housing 100 of the Sendzimir mill shown in FIG. Rolled.
At that time, the work roll is made of high speed steel, the roll body is tempered at 550 ° C. (the tempering temperature is determined in FIG. 3), and the hardness of the roll body is HRC over the roll body length direction: 68 Nine pairs of work rolls that are uniform are manufactured, and only the end of the roll cylinder is further tempered at different temperatures exceeding 550 ° C. based on FIG. As shown in FIG. 4, 7 pairs of work rolls having an HRC in the range of 5 to 20 were obtained. Here, in the case of a work roll made of high-speed steel, if the hardness difference between the roll barrel end and the roll barrel center exceeds 20 in HRC, the metal structure of the roll undergoes thermal distortion during high temperature tempering. Since the probability that the work roll breaks increases, the manufacturing is difficult.
[0017]
Incidentally, the 900mm in contact with the plate width W _A of more material to be rolled most rolling frequently the length A of the roll body central portion, the length of the roll barrel ends B, C was 200mm respectively.
Further, the roll body portion is tempered at 550 ° C., and the hardness of the roll body portion is uniform at HRC: 68 over the roll body length direction, and one of the two pairs of work rolls described above is: A conventional work roll having a diameter difference in the roll cylinder length direction and a roll cylinder hardness of HRC: 68 was obtained.
[0018]
The result of cold rolling stainless steel foil using these work rolls is as shown in FIG. However, the comparison was made by applying to a rolling pass with a plate thickness of 0.100 mm or less. The difference in hardness shown on the horizontal axis is an average obtained by adding the difference in hardness at the upper roll and the difference in hardness at the lower roll and dividing by two. Further, during rolling, the plate width variation of the rolled material and the meandering of the rolled material were ± 1 mm or less in total.
[0019]
When using a work roll that is within the scope of the present invention, when using a pair of work rolls in which the hardness difference between the center part of the roll cylinder and the end part of the roll cylinder is 5 in HRC. Thus, it can be seen that the rolling distance until cracks are generated can be increased.
Moreover, when performing cold rolling of stainless steel foil, it is a work roll whose hardness difference between the roll barrel end and the roll barrel center is 10 to 15 in HRC. This is preferable because the rolling distance until cracks can be remarkably increased without being generated.
[0020]
The remaining pair of work rolls has a length A at the center of the roll cylinder of 920 mm so that the margin E is 10 mm per side with respect to the sheet width of 900 mm of the material to be rolled with the highest rolling frequency. The length B and C of the cylinder end were 190 mm, and the diameter of the roll cylinder end was ground 0.19 mm smaller than the diameter of the center of the roll cylinder to obtain a work roll 10 of a comparative example (see FIG. 8). When the work roll 10 of the comparative example was used, when the rolling distance exceeded about 70 km, a crack occurred in the portion where the roll kiss occurred, and as a result of continuing the rolling, the spalling caused by the crack and the material to be rolled Breaking occurred.
[0021]
【The invention's effect】
According to the present invention, even when used in a roll kiss situation, rolling can be performed for a long distance without generating cracks at the end of the roll body where roll kiss occurs. Further, according to the present invention, it is possible to prevent breakage of the material to be rolled even when there is a variation in the plate width of the material to be rolled or meandering of the material to be rolled.
[0022]
As a result, the roll basic unit of the work roll can be improved, and the cold rolling of the metal foil can be performed stably.
[Brief description of the drawings]
FIG. 1A is a schematic view of a roll body portion of a work roll according to the present invention, and FIG. 1B is a schematic view of a roll kiss state when the work roll is used.
FIG. 2 is a graph showing an example of the relationship between hardness and absorbed energy of a specimen of a steel work roll material.
FIG. 3 is a graph showing an example of the relationship between the tempering temperature and the hardness of a steel work roll.
FIG. 4 is a graph showing an example of the effect when the present invention is applied.
FIG. 5 is a roll layout diagram of a rolling mill to which the present invention is applied.
FIG. 6 is a schematic diagram for explaining elastic deformation of a work roll.
FIG. 7 is a schematic diagram for explaining a roll kiss at the time of rolling.
FIG. 8 is a schematic diagram showing a roll body shape of a conventional metal foil rolling work roll.
[Explanation of symbols]
S Rolled material 1, 10 Work roll 2 Roll cylinder center 3 Roll cylinder end A Length of roll cylinder central B, C Length of roll cylinder end D Roll cylinder length W Plate width
100 Sendzimir rolling mill housing
1a, 1a 'roll axis
1b, 1b 'roll body surface
1C Part E where roll kiss occurs E

Claims (2)

The roll body is made of steel, the hardness of the center part of the roll body in contact with the material to be rolled is HRC: 63 to 73, the hardness of the roll body ends on both sides thereof is HRC: 53 to 58, and the roll A work roll for rolling metal foil, wherein the difference in hardness between the center of the cylinder and the end of the roll cylinder is more than 5 and less than 20 in HRC. The work roll for metal foil rolling according to claim 1, wherein a difference in hardness between the center of the roll cylinder and the end of the roll cylinder is 10 to 15 in terms of HRC.

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