JPH0767567B2 - Shape control method in strip rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a cold rolling method in which the width of a rolled material plate is changed from a narrow material to a wide material, and the width of the roll is wide over almost the entire region. The present invention relates to a shape control method in material rolling.

[Conventional technology]

In the cold rolling method, when the strip width is reversed from a narrow strip to a wide strip, a large middle stretch due to the thermal crown of the work roll or a large middle stretch and a co-occurrence of the selvage wave occur, In that case, the plate is broken.

Conventionally, when performing plate width reverse rolling with a large difference in plate width, work roll rearrangement is performed by a method described in, for example, Japanese Utility Model Publication No. 47-23135. And
A cooling medium such as water, rolling oil, or cryogenic air is sprayed on the work roll by dividing it in the width direction and adjusting until the target shape or target thermal crown is obtained. This method is a technology that assumes that the heat source for all heat generation is between the rolled material and the work roll. When using this method,
The large inward extension can be eliminated by controlling the roll cooling system inside and outside the board path.

[Problems to be solved by the invention]

However, the rolling width of the rolled material is changed only from the wide to the narrow direction, or the amount of change to the wide width is, for example, 50 mm or less in the case of reversing into a small plate width, or a thermal crown. In the case of low thermal crown rolling in which the amount that affects the shape can be ignored, the conventional method does not cause any serious problems, but rolling that causes excessive bearing heat generation, such as when rolling rolled material coils continuously. In the material, the thermal crown generated by the heat generation of the bearing becomes a state that cannot be ignored, and if the wide material is rolled with this roll, the shape becomes defective.

Therefore, it is an object of the present invention to prevent the occurrence of a shape defect due to a thermal crown due to heat generation of a bearing, which has been a problem when rolling with changing the plate width from a narrow material to a wide material.

Further, not only when the strip width of the rolled material coil is changed from the narrow width to the wide width, but also in the rolling of the wide material which is rolled to the full length of the roll cylinder, similarly, there is a problem of occurrence of shape defect. The purpose is also to prevent.

[Means for solving problems]

To achieve this object, the shape control method of the present invention, when rolling a rolled material, cools the work roll inside the strip of the rolled material, reduces the degree of cooling of the work roll outside the strip, and chocks. In the vicinity, the work roll is cooled and rolled.

[Action]

A proper roll thermal crown is required to obtain a good shape. The amount and shape of the thermal crown is
A gentle mountain-shaped crown that is determined by the deformation of the rolled material and rolls is optimal. In cold rolling and temper rolling, according to the conventional idea, the heat transferred from the rolled material to the work rolls is large, the heat on the work roll side has little effect on the rolled material, and the chock heat generated by bearing heat generation is small. The rise has been ignored. However, according to the findings of the present inventors, it was found that the effect of heat of the chock on the thermal crown cannot be ignored. Especially when trying to use the full width of the work roll as compared to the width of the body of the work roll,
The heat of the chock has a considerable effect on the thermal crown.

The present invention is based on such knowledge, in order to ensure a proper thermal crown for rolled material of any strip width, roll cooling inside the strip, roll cooling reduction outside the strip, rolls near the chock Cool down. When rolling is performed in a state in which the thermal crown is not properly formed, such as immediately after roll reshuffling, heating the rolls in the strip and heating them should be done normally in preparation for startup and restart. Be seen.

〔Example〕

Hereinafter, features of the present invention will be specifically described with reference to examples.

FIG. 1 is a plan view showing a cooling device around a rolling stand for carrying out the present invention, and FIG. 2 is a side view thereof. In the figure, 1 is a rolled material rolled by the work roll 2.
Both ends of the work roll 2 are supported by chocks 3.
Backup rolls 4 are arranged above and below the work roll 2. The work roll 2 is provided with a coolant header 5 for injecting rolling oil for cooling and lubrication, that is, a coolant. The coolant header 5 is provided with a plurality of nozzles along the longitudinal direction of the work roll 2, and the cooling capacity can be controlled for each nozzle.

Further, nozzles a and b are nozzles for inside and outside of the board passage,
The widthwise areas of a and b can be changed depending on the width of the threaded plate. Nozzle c does not depend on the plate width, near the chock,
That is, as shown in FIG. 1, it is arranged for the purpose of cooling the part including the roll end and the roll neck.

As a device for carrying out the present invention, because it is arranged to control the cooling of the work roll in the width direction of the rolled material,
It is necessary to have equipment capable of changing the cooling capacity of the work rolls in the width direction of the rolled material. Further, in order to prevent the heat transfer from the chock from affecting the roll thermal crown, it is desirable to have a mechanism that makes it difficult for the bearing heat generation of the work roll to be transferred to the body of the roll. The rolling control device is configured under such conditions.

In the apparatus shown in FIG. 1 and FIG. 2, when the strip width is changed from the narrow width to the wide width w and the rolled material 1 is rolled, the following control is performed on the strip path of the wide material. .

(I) Increase the flow rate / pressure of the coolant and / or increase the heat transfer area in the plate passage a.

(Ii) The flow rate and pressure of the coolant outside the board passage b and / or the heat transfer area are reduced.

(Iii) Increase the flow rate / pressure of the coolant and / or increase the heat transfer area in the vicinity c of the chock. Alternatively, the coolant flow rate should be sufficiently high to maintain the supercooled state.

Such control is performed before passing the wide material, and when the wide material is passed, rolling is performed with a thermal crown adapted to the wide material. The shape of the narrow material rolled during the thermal crown change does not cause a large shape defect.

3 and 4 show the thermal crown and the shape when the control of the present invention is performed and when it is not performed. According to Fig. 3, the thermal crown (a) suitable for the plate width of 712 mm has a large steepness as shown in Fig. 4 (a) when the plate width is 900 mm. This indicates that the product is defective. On the other hand, when the thermal crown control of the present invention is performed as shown in FIG. 3 (b), a gentle thermal crown curve with a small head up to a plate width of 900 mm is obtained, and the inflection point of the thermal crown curve is the plate. Since it is pushed out of the road, it shows that a non-defective product with little variation in the width direction can be obtained as in the steepness shown in FIG. 4 (b).

〔The invention's effect〕

As described above, in the present invention, the cooling control of the inside and outside of the board passage and the vicinity of the chock is performed so that the heat generation of the bearing of the work roll does not affect the thermal crown. As a result, the shape of the thermal crown of the work roll is gentle in the plate end portion and in the vicinity of the chock and the drop is small, so that the heat inflow from the chock can be prevented. As a result, the thermal crown is properly maintained, and a rolled material having a good shape can be stably secured.

[Brief description of drawings]

FIG. 1 is a plan view of an apparatus for carrying out the present invention, FIG. 2 is a side view thereof, FIGS. 3 and 4 show the effect of the present invention, and FIG. Crown, FIG. 4 is a graph showing steepness in the plate width direction.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fuyasu Yamamoto 1-1-1, Emitsu, Hachimanto-ku, Kitakyushu, Fukuoka Prefecture, Nippon Steel & Co., Ltd. Third Technical Research Institute (56) Reference JP-A-58- 128208 (JP, A) JP 59-16608 (JP, A)

Claims (1)

[Claims] 1. When rolling a rolled material, the work roll is strongly cooled inside the strip of the rolled material, the degree of cooling of the work roll is reduced outside the strip, and the body end portion of the work roll and A shape control method in plate rolling, characterized in that the roll neck is strongly cooled and rolled.