JP3106687B2 - Method of preventing generation of touch marks when rolling mill is opened - 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 preventing generation of touch marks when a rolling mill is opened, and more particularly, to reliably prevent touch marks from being formed on a rolling roll due to the tension of a steel sheet when the rolling mill is opened. And a method for preventing 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 a thin steel sheet 2 is continuously temper-rolled by a two-stand temper rolling mill 1, the steel sheet 2 passes through an entrance-side tension roll 3. Then, the steel sheet passes through the first and second stands 1A and 1B of the rolling mill 1 and is subjected to temper rolling, and then passes through the exit-side tension roll 4 and moves to the next step.

[0003] When the steel sheet 2 is subjected to the temper rolling continuously, it is necessary that the welded portion between the steel sheet 2 and the steel sheet 2 be passed through the rolling mill 1.

Conventionally, in such a case, when the welded portion of the steel sheet 2 reaches the entry side of the rolling mill 1, the entry 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 welding portion passes through the rolling mill 1, the rolling roll is returned to the original state, and the rolling is resumed. Was. Hereinafter, this method will be referred to as Conventional Technique 1.
That.

[0005] However, when the rolling mill 1 is opened,
The rolling roll and the steel plate 2 rub against each other, causing
A so-called touch mark is attached. When the touch mark is attached to the rolling roll in this manner, the surface flaw is transferred to the steel sheet 2 during the next rolling of the steel sheet, and becomes a serious defect. The reason why the rolling roll rubs against the steel sheet 2 is that the tension (A) of the steel sheet 2 between the first and second stands 1A and 1B is the tension (B) of the steel sheet 2 on the entrance side and the exit side of the rolling mill 1 (B) This is because 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 problem,
Before the rolling mill 1 is opened, a method of lowering the tensions (A), (B) and (C) by lowering the auxiliary rolls 5A and 5B from the pass line of the steel plate 2 has been adopted. Hereinafter, this method is referred to as Conventional Technique 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,
The generation of touch marks could not be reliably prevented.

Accordingly, an object of the present invention is to provide a method capable of easily and surely preventing generation of a touch mark generated when a rolling mill is opened.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a rolling mill having at least one rolling stand is provided with an incoming tension roll on the steel sheet input side and an output tension roll on the steel sheet output side. In doing so, first stop the exit tension roll, then sequentially stop the rolling stand from the downstream side in the steel sheet moving direction, and finally stop the entrance tension roll is characterized in that. is there.

One embodiment of the method for preventing the occurrence 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.

According to the present invention, first, the delivery-side tension roll 4 is stopped, and then the second stand 1B of the rolling mill 1 is stopped. In this way, after stopping the delivery-side tension roll 4, the second stand 1B is stopped, so that the steel plate 2
Is slightly sent to the output side tension roll 4 side,
The tension (C) of the steel plate 2 between the exit tension roll 4 and the second stand 1B decreases. Next, the first stand 1A is stopped. As described above, 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. Next, the entrance-side tension roll 3 is stopped. In this way, after stopping the first stand 1A, the steel plate 2 is slightly sent to the first stand 1A side by stopping the entry-side tension roll 3, so that the first stand 1A and the entry-side tension roll 3 are stopped. , The tension (B) of the steel sheet 2 decreases. Thus, by stopping the exit side tension roll 4, the second stand 1B, the first stand 1A, and the entrance side tension roll 3 in this order, the tensions (A), (B),
(C) is reduced, so that even when the rolling mill 1 is opened, a touch mark is not easily attached to the rolling roll.

In this case, before the rolling mill 1 is opened,
If 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, so that the touch mark is less likely to be attached.

According to the present invention, the tension at the time of stopping the output side tension roll 4, the second stand 1B, the first stand 1A, and the entrance side tension roll 3 in this order, and then lowering the auxiliary rolls 5A and 5B. The reduction effects of (A), (B) and (C) were examined. This result is compared with the above-mentioned prior art 1
The results are shown in Table 1 in comparison with Tables 2 and 3.

[0015]

[Table 1]

As apparent from Table 1, according to the present invention, the tension (B) of the steel plate 2 on the entry side of the rolling mill 1 and the tension between the first and second stands 1A and 1B are different from those of the prior arts 1 and 2. Both the tension (A) of the steel sheet 2 and the tension (C) of the steel sheet 2 on the exit side of the rolling mill 1 are greatly reduced. Therefore, it was found that even when the rolling mill 1 was opened, a touch mark was hardly attached to the roll.

[0017]

As described above, according to the present invention, the exit tension roll, the rolling mill, and the entry tension roll are sequentially stopped in this order, and the auxiliary roll is lowered if necessary. There is provided a useful effect that it is possible to easily and reliably prevent generation of touch marks generated when the rolling mill is opened.

[Brief description of the drawings]

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

[Description of Signs] 1: Temper rolling mill, 2: Steel plate, 3: Tension roll on entry side, 4: Tension roll on exit side, 5A, 5B: Auxiliary roll.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21B 39/08 B21B 1/22

Claims (2)

(57) [Claims] When a rolling mill having at least one rolling stand is provided with an entrance tension roll on the steel sheet input side and an output tension roll on the steel sheet exit side, the rolling mill is first opened. Stop the side tension roll,
Next, 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, wherein a touch mark is prevented from being generated when the rolling mill is opened. 2. The method according to claim 1, wherein the auxiliary roll of the rolling mill is lowered after stopping the entrance tension roll.