JPH05305323A - Method for preventing generation of touchmark when rolling mill is opened - Google Patents

Abstract

PURPOSE:To easily and surely prevent generation of a touch mark when a rolling mill is opened. CONSTITUTION:When a rolling mill 1 provided with an inlet side tension roll 3 on the inlet side of a steel plate of the rolling roll 1 having at least one rolling stand and an outlet side tension roll 4 on the outlet side of the steel is opened, the outlet side tension roll 4 is stopped, then, the rolling stands of the rolling mill 1 are stopped in sequence from the downstream side in the moving direction of the steel plate and the inlet side tension roll 3 is stopped finally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the generation of touch marks when a rolling mill is opened, and more particularly, to reliably prevent a touch mark from being applied to a rolling roll by the tension of a steel plate when the rolling mill is opened. The present invention relates to a method for preventing the generation of touch marks when the rolling mill is opened.

[0002]

2. Description of the Related Art As shown in FIG. 1, for example, when temper rolling is performed on a thin steel sheet 2 by a two-stand temper rolling machine 1, the steel sheet 2 passes through an inlet side tension roll 3. Then, temper rolling is performed by passing through the first and second stands 1A and 1B of the rolling mill 1, and then, passing through the exit side tension roll 4 to move to the next step.

In this way, when the steel sheet 2 is continuously temper-rolled, the welded portion of the steel sheet 2 needs to pass through the rolling mill 1.

Conventionally, in such a case, when the welded portion of the steel plate 2 reaches the entrance side of the rolling mill 1, the entrance side tension roll 3, the first and second stands 1A, 1B, and
The exit side tension roll 4 is stopped at the same time, and then the rolling mill 1 is opened, that is, the rolling roll is opened, and after the welded portion has passed through the rolling mill 1, the rolling roll is returned to the original state and the rolling is restarted. Was. Hereinafter, this method is referred to as Prior Art 1
Say.

However, when the rolling mill 1 is opened,
The rolling roll and the steel plate 2 rub against each other, and the rolling roll has a surface flaw,
So-called touch marks are attached. When the touch mark is attached to the rolling roll in this way, the surface flaw is transferred to the steel plate 2 at the time of the next rolling of the steel plate, which becomes a serious defect. The reason why the rolling roll and the steel plate 2 rub against each other is that the tension (A) of the steel plate 2 between the first and second stands 1A and 1B is the tension (B), (C) of the steel plate 2 on the inlet side and the outlet side of the rolling mill 1. ), The steel plate 2 is pulled in the direction of the arrow in the figure at the same time when the rolling mill is opened.

Therefore, in order to solve the above-mentioned problems,
Before the rolling mill 1 is opened, the auxiliary rolls 5A and 5B are lowered from the pass line of the steel plate 2 to reduce the tensions (A), (B) and (C). Hereinafter, this method is referred to as Prior Art 2.

[0007]

However, even if the auxiliary rolls 5A and 5B are lowered from the pass line, the tension (A),
(B) and (C) cannot be reduced sufficiently, therefore
It was not possible to reliably prevent the generation of touch marks.

Therefore, an object of the present invention is to provide a method capable of easily and reliably preventing the generation of touch marks that occur when the rolling mill is opened.

[0009]

According to the present invention, a rolling mill having at least one rolling stand is provided with an inlet side tension roll on the steel sheet inlet side, and an outlet side tension roll is provided on the steel sheet outlet side. In doing so, first, the exit side tension roll is stopped, then the rolling stand is sequentially stopped from the downstream side in the steel sheet moving direction, and finally the entrance side tension roll is stopped. is there.

An embodiment of a method for preventing the generation of touch marks when the rolling mill is opened according to the present invention will be described with reference to the drawings.

A case where the present invention is applied to a two-stand temper rolling mill as shown in FIG. 1 will be described.

In the present invention, first, the exit side tension roll 4 is stopped, and then the second stand 1B of the rolling mill 1 is stopped. In this way, by stopping the output side tension roll 4 and then stopping the second stand 1B, the steel plate 2
Is slightly sent to the exit side tension roll 4 side,
The tension (C) of the steel plate 2 between the exit side tension roll 4 and the second stand 1B decreases. Then, the first stand 1A is stopped. In this way, by stopping the first stand 1A after stopping the second stand 1B, the steel plate 2 is slightly sent to the second stand 1B side.
The tension (A) of the steel plate 2 between the first stand 1A and the first stand 1A decreases. Then, the entrance tension roll 3 is stopped. In this way, by stopping the first stand 1A and then stopping the entry side tension roll 3, the steel plate 2 is slightly sent to the first stand 1A side, so that the first stand 1A and the entry side tension roll 3 The tension (B) of the steel plate 2 between and decreases. Thus, by stopping the output side tension roll 4, the second stand 1B, the first stand 1A, and the input side tension roll 3 in this order, the tensions (A), (B),
(C) is reduced, so even if the rolling mill 1 is opened, it is difficult for the rolling roll to have touch marks.

In this case, before opening the rolling mill 1, the first
When the auxiliary roll 5A of the stand 1A and the auxiliary roll 5B of the second stand 1B are lowered, the tension of the steel plate 2 is further reduced, and the touch mark is more difficult to be attached.

According to the present invention, the tension at the time when the exit side tension roll 4, the second stand 1B, the first stand 1A and the entry side tension roll 3 are stopped in this order, and then the auxiliary rolls 5A and 5B are lowered, The reduction effects of (A), (B) and (C) were investigated. This result is referred to as the above-mentioned prior art 1
And shown in Table 1 in comparison with 2.

[0015]

[Table 1]

As is clear from Table 1, according to the present invention, the tension (B) of the steel plate 2 on the inlet side of the rolling mill 1 and the distance between the first and second stands 1A and 1B are higher than those of the prior arts 1 and 2. Both the tension (A) of the steel plate 2 and the tension (C) of the steel plate 2 on the delivery side of the rolling mill 1 are significantly reduced. Therefore, it was found that even if the rolling mill 1 was opened, it was difficult for the roll to have touch marks.

[0017]

As described above, according to the present invention, the exit side tension roll, the rolling mill, and the entrance side tension roll are sequentially stopped in this order, and further the auxiliary roll is lowered as necessary, It is possible to easily and surely prevent the generation of touch marks that occur when the rolling mill is opened, which is a useful effect.

[Brief description of drawings]

FIG. 1 is a schematic front view of a temper rolling mill.

[Explanation of symbols]

 1: Temper rolling mill, 2: Steel plate, 3: Entrance side tension roll, 4: Exit side tension roll, 5A, 5B: Auxiliary roll.

Claims (2)

[Claims] 1. A rolling mill having at least one rolling stand, which comprises an inlet side tension roll on the steel sheet inlet side and an outlet side tension roll on the steel sheet outlet side, is first opened when the rolling mill is opened. Stop the side tension roll,
Then, the rolling stand is sequentially stopped from the downstream side in the steel sheet moving direction, and finally, the entrance side tension roll is stopped, whereby a touch mark is prevented from being generated when the rolling mill is opened. 2. The method according to claim 1, further comprising lowering the auxiliary roll of the rolling mill after stopping the inlet tension roll.