JPS63264209A - Control method for shape in sheet rolling - Google Patents

Abstract

PURPOSE:To bring a thermal crown to be proper by the prevention of heat in flow from chocks and to bring a rolled stock to have a good shape by relatively reducing cooling outside the sheet passing zone to cooling inside the sheet passing zone for work roll of sheet rolling and increasing the cooling near the chocks. CONSTITUTION:The cooling for outside the sheet passing zones (b) of the sheet passing zone (a) of a work roll 2 rolling a wide sheet stock 1 is relatively reduced to the cooling by coolant headers 5 for the zone (a) to form a thermal crown of the roll 2 into a good shape. Further the cooling for zones (c) near the chocks 3 is increased to prevent the inflow of heat generating in the chocks 3 into the roll 2. Thus, the temp. different at sheet ends is reduced and the thermal crown amount of the roll 2 is properly maintained so as to surely and stably obtain the rolled stocks having a good shape.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is applicable to cold rolling when changing the width of a rolled material from a narrow material to a wide material, and when changing the width of a rolled material from a narrow material to a wide material, and when changing the width of a rolled material from a narrow material to a wide material, and This invention relates to a shape control method in rolling material.

[Conventional technology]

In the cold rolling method, when the width of the rolled material is reversed from a narrow material to a wide material, a large elongation due to the thermal crown of the work roll, or a shape in which large elongation and ear waves occur together, occurs. In extreme cases, the plate will break.

Conventionally, when performing sheet width reverse rolling with a large difference in sheet width, the work rolls have been rearranged by a method such as that described in Japanese Utility Model Publication No. 47-23135. Then, add water and rolling oil to the work roll.

Cooling medium such as cryogenic air is sprayed in widthwise direction,
A method is used in which adjustments are made 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, large elongation in the middle can be solved by controlling the roll cooling system inside and outside the boardwalk.

[Problem that the invention seeks to solve]

However, rolling where the strip width of the rolled material changes only from wide to narrow, or rolling where the change from wide to wide is reversed to a minute strip width of, for example, 50 AUa or less, or when thermal crown is In the case of low-thermal crown rolling where the amount that affects the shape is negligible, the conventional method does not cause any major problems, but rolling where the bearing heat generation is excessive, such as when rolling rolled material coils continuously If a wide material is rolled with a roll that has a non-negligible thermal crown, the thermal crown caused by the heat generated by the bearings will result in poor shape.

Therefore, an object of the present invention is to prevent the occurrence of shape defects caused by thermal crowns due to bearing heat generation, which has been a problem when changing the sheet width from a narrow material to a wide material and rolling.

In addition, not only when the width of the rolled material coil is changed from narrow to wide, but also when rolling a wide material that is rolled over a long roll cylinder, there is a similar problem of shape defects. The purpose is to prevent this as well.

[Means for solving problems]

In order to achieve this objective, the shape control method of the present invention cools the work rolls within the board track of the rolled material, reduces the degree of cooling of the work roll outside the board track, and chocks the rolled material. In the vicinity, rolling is performed using a predetermined thermal crown after cooling the work roll.

[Effect]

A proper rolled thermal crown is necessary to obtain a good shape. The collapse and shape of the thermal crown are
A gentle chevron-shaped crown determined by the deformation of the rolled material and rolls is optimal. In cold rolling and temper rolling, according to the conventional thinking, a large amount of heat is transferred from the rolled material to the work roll, and the heat on the work roll side has little effect on the rolled material, and the chock heat generated by bearing heat generation is The rise has been ignored. However, according to the findings of the present inventors, it has been found that the influence of the heat of the chock on the thermal crown cannot be ignored.

In particular, when trying to use the full width of the work roll compared to the width of the body, the heat of the chock has a considerable effect on the thermal crown.

The present invention is based on this knowledge, and in order to ensure an appropriate thermal crown for rolled materials of any width, the present invention aims to reduce the cooling of the rolls inside the plateway, reduce the cooling of the rolls outside the plateway, and reduce the cooling of the rolls near the chocks. Perform cooling. Further, when rolling is performed in a state where the thermal crown is not properly formed, such as immediately after the rolls are rearranged, heat generation is performed by heating the rolls in the board path.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained 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 work rolls 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, coolant. This coolant header 5 is equipped with a plurality of nozzles along the longitudinal direction of the work roll 2, and allows the cooling capacity of each nozzle to be controlled.

Since the apparatus for carrying out the present invention controls the cooling of the work roll in the width direction of the rolled material,
It is necessary to have equipment that can change the cooling capacity of the work rolls in the width direction of the rolled material. Further, in order to prevent heat transfer from the chock from affecting the roll thermal crown, it is desirable to have a mechanism that prevents heat generated by the bearings of the work roll from being transferred to the body of the roll. The rolling control device is constructed under such conditions.

In the apparatus shown in Figs. 1 and 2, when rolling a rolled material l by changing the plate width from narrow to wide W, the following control is performed on the plate path of the wide material. .

(i) Increase in flow rate and pressure of coolant in boardwalk a and/or
Or increase the heat transfer area.

(ii) Reduce the coolant flow rate/pressure source and/or heat transfer area outside the plank road.

(iii) Coolant flow rate near chock C
Increase pressure and/or heat transfer area. Alternatively, the coolant flow rate is increased sufficiently to maintain a supercooled state.

Such control is performed before passing the wide material, and when passing the wide material, rolling is performed using a thermal crown suitable for the wide material. The shape of the narrow material rolled during the thermal crown change does not suffer from major shape defects.

FIGS. 3 and 4 show the thermal crown and its shape with and without the control of the present invention, respectively. According to Fig. 3, the thermal crown (a) suitable for a plate width of 712 mm has a plate width of 9Of.
) When the cylinder is used as it is, the steepness is large as shown in FIG. 4(a), indicating 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), the plate width is 900 mm.
A gentle thermal crown curve with a small drop is obtained, and the inflection point of the thermal crown curve is pushed out of the boardwalk, so the steepness in the width direction is as shown in (b) in Figure 4. This shows that a good product with little variation can be obtained.

〔Effect of the invention〕

As explained above, in the present invention, cooling control is performed on the inside and outside of the boardway and in the vicinity of the chock so that the heat generated by the bearings of the work roll does not affect the thermal crown. As a result, the thermal crown shape of the work roll is smooth and has a small drop in the vicinity of the plate end and the chock, and heat inflow from the chock can be prevented. As a result, the thermal crown is properly maintained,
It is possible to ensure a stable and well-shaped rolled material.

[Brief explanation of drawings]

Fig. 1 is a plan view of an apparatus for implementing the present invention, Fig. 2 is a side view thereof, Figs. 3 and 4 show the effects of the present invention, and Fig. 3 is a thermal image of a work roll. Crown, FIG. 4 is a graph showing the steepness in the width direction of the plate. Patent Applicant Nippon Steel Co., Ltd. Representative Masaru Okohori (and 2 others) No. 1vA Figure 2 No. 3vA

Claims (1)

[Claims] 1. When rolling a rolled material, the work roll is cooled within the plateway of the rolled material, the degree of cooling of the work roll is reduced outside the plateway, and the work roll is cooled to a predetermined thermal temperature near the chock. A shape control method in plate rolling characterized by rolling with a crown.