JPH0549366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of rolling a plate material using a moving work roll rolling mill.

(Prior art) In general, when rolling plate materials, as the number of sheets of material with the same width increases, as shown in Fig. 5,
The plate track portions of the upper and lower work rolls wear more than other parts, and the part of the work roll that comes into contact with the edge of the plate width has a wear rate of 10 to 20 mm compared to the center part of the plate width due to a phenomenon called edge wear. % is known to wear out significantly. If such a work roll continues to roll a material of the same width or a wider width, abnormal protrusions called high spots will be formed on the cross section of the rolled material, resulting in quality defects in the product.

To prevent this, for example, U.S. Pat.
As disclosed in Japanese Patent Publication No. 2047883, Japanese Patent Publication No. 59-38842, etc., a technique has been proposed in which upper and lower work rolls are moved in the axial direction of each rolled material one by one or several rolled materials. Coupled with the development of a movable rolling mill, it has been applied to actual operations, and the above-mentioned wear dispersion effect has been improved. In addition, when the work roll is cyclically moved in the direction of the roll axis to disperse wear on the work roll,
It has been found that the axial distribution of the thermal expansion of the roll, the so-called thermal crown, is also smoothed, as disclosed in No. 113,903.

On the other hand, in recent years, there has been a demand for improved thickness accuracy in the width direction of rolled materials in order to improve yield, and various methods for controlling sheet crown and edge drop have been proposed. Among these, a control method using a rolling mill that moves work rolls in the axial direction is attracting attention as a relatively simple method. However, in a type of rolling mill in which the work rolls are moved in the axial direction, in order to increase the controllability of the plate crown, the work rolls should be set as far away from the center of the mill as possible, as shown in Figure 6. It is necessary. Furthermore, as disclosed in JP-A-55-77903, there is a method in which edge drops are reduced by applying a tapered grinding shape to one end of the work roll and bringing the width end of the rolled material into contact with this part. It is necessary to set the work roll as far away from the center of the mill as possible depending on the width of the material.

(Problems to be Solved by the Invention) As mentioned above, the purpose of the rolling mill that moves the work rolls in the axial direction is to relieve the rolling schedule by dispersing wear on the work rolls and smoothing the thermal crown. It was developed for the purpose of controlling the plate crown and/or edge drop of rolled material, but when these two purposes cannot be simultaneously satisfied with a single function of moving the work roll in the axial direction. There are many. Therefore, in order to supplement this function, many recent work roll axially movable mills are equipped with roll bending devices that are more powerful than conventional mills. However, there is a limit to the ability to strengthen the roll bending force due to constraints such as bearing life.Especially when rolling thin materials or high-tensile materials with a small plate crown, or when rolling materials for which edge drop should be reduced, it is difficult to strengthen the work roll. It is necessary to set it as far away from the center of the mill as possible.

In order to solve this problem, as an operational countermeasure, we have developed materials that are required to reduce plate crown and/or edge drop (hereinafter referred to as ``plate crown-required materials'').
) and other materials (hereinafter referred to as "general materials") are separated into separate roll chances. According to this method, when rolling material requiring a plate crown, the work roll is placed at the center of the mill. Rolling is performed by fixing the work roll at a position as far away as possible from the work roll.On the other hand, when rolling general materials, the work roll is moved cyclically to disperse wear on the work roll. However, with this method, it is not possible to disperse the wear of the work rolls when rolling a sheet crown-required material continuously. Further, there is a problem in that the rolling chance of the material is severely restricted.

The present invention has been made in view of the above-mentioned circumstances, and effectively utilizes the functions of a moving work roll rolling mill to alleviate rolling chance constraints by dispersing work roll wear and improve plate crown and edge drop control functions. It is an object of the present invention to provide a method for rolling a plate material that is compatible with the above features.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a plate material that cyclically moves the upper and lower work rolls in opposite directions along the axial direction each time the material is rolled. The rolling method is characterized by referring to information on the finished plate thickness, plate width, and target crown and/or target edge drop of each of a plurality of subsequent rolled materials, and changing the cyclic movement pattern of the work roll based on the information. That is. In particular, in one specific aspect, when two or more sheets of plate crown-required material are continuously rolled, the work roll is moved to a position as far away from the center of the mill as possible, and the general material is continuously rolled. The purpose is to move the work roll cyclically with a smaller amplitude than the cyclic movement of the work roll when the work roll is moved.

The present invention will be explained in detail below based on examples.

First, in the present invention, regardless of whether the rolled material is a sheet crown-required material or a general material, the upper and lower work rolls are cyclically moved in opposite directions along the axial direction for each rolling. In addition, the following measures are applied to obtain the effect of controlling plate crown and edge drop.

Next, in the present invention, the reason for referring to information on the finished plate thickness, plate width, and target plate crown and/or target edge drop of each of a plurality of subsequent rolled materials is as follows.

In plate rolling, to improve productivity,
There is a demand for shortening the time between one pass. For example, in finish rolling on a hot strip mill, the typical interpass time is 10 to 20 seconds. on the other hand,
In order to move the work roll in a rolling mill that moves the work roll in the axial direction, the roll bending force must be lowered to a certain value, and the rotational speed of the roll must be set to an appropriate value that allows the work roll to slide in the axial direction. It is necessary to move the work roll after setting it to , and then set the roll bending force and roll rotation speed to values appropriate for rolling the next material. The amount of movement is at most 100mm. This movable amount becomes smaller as the inter-pass time becomes shorter. Therefore, if information about the subsequent rolled material is not known in advance and the next material requires a plate crown, it will be impossible to move the work roll to the appropriate position for that rolled material. Cases may occur.

In order to prevent this, it is necessary to know the above information regarding the subsequent rolled material in advance. For this purpose, the number of subsequent rolling materials to be referenced is N 0 , where δmax is the maximum movable position of the work roll from the mill center, and S is the amount of work roll movement between one rolling pass _. It becomes an integer N ₀ that satisfies =≧δmax/S.

In addition, if there is a material that requires a plate crown for the subsequent rolled material, in order to be able to set the work roll at the appropriate position when it is the turn to roll that material, it is necessary to ≦N ₀ ), then from the maximum movement position δ′max of the work roll determined from the plate width of the material (δ′max≦δmax) and the current position δ _A of the work roll, N≧δ′max −δ _A /S must be satisfied.

On the other hand, when rolling a sheet crown-required material continuously, from the viewpoint of increasing the control range of the sheet crown and edge drop, it is recommended to fix the work roll at a position as far away from the center of the mill as possible depending on the sheet width. Although it is desirable, as shown in Fig. 6, if the distance from the work roll body end to the strip width end of the rolled material is small within a certain range, a sufficient control range for the strip crown and edge drop can be obtained. There are many. Therefore, by cyclically moving the work roll within this range, it is possible to achieve both the effect of dispersing the wear of the work roll and the effect of controlling plate crown and edge drop. The cyclic movement amplitude of the work roll when continuously rolling the above plate crown required material is
It is desirable that the length be 200 mm or less, preferably 100 mm or less. If the work roll position is set within this range, the rolling load determined from the set position, the roll profile during rolling formed by the roll's thermal crown and wear, the size of the rolled material, deformation resistance, and rolling schedule. In addition, even if the plate crown control range calculated from the functional range of roll bending force does not satisfy the target plate crown, it is possible to satisfy the target plate crown by changing the amount of axial movement of the work roll. can.

The amplitude of the cyclic movement of the work roll in the case of continuous rolling of general materials is determined by the constraints of the work roll axial movement device, and is generally 300 to 1000 mm in many cases.

Next, one embodiment of the present invention will be described with reference to the drawings.

(Example) Fig. 1 is a diagram showing the arrangement of hot strip mill finishing stands, in which the first stand 1, second stand 2, and second stand 3 are conventional four-tiered stands in which the work roll 8 does not move in the axial direction. Although it is a rolling mill, the fourth
Stands 4 to 7 are rolling mills that move work rolls in the axial direction, and the axial movement stroke of the upper and lower work rolls 9 is 600 mm.
It is. Incidentally, the body length of the work rolls 8 and 9 is 2180 mm in both stands. 10 is a rolled material, 1
1 is a plate crown meter.

FIG. 2 shows the plate width configuration of a rolled material rolled using this rolling mill, and the rolled material within the hatched area in the figure is a material requiring a plate crown. In addition, even in the conventional rolling method carried out for comparison, the second
Rolling was carried out by preparing a rolled material with a size configuration similar to that shown in the figure.

FIG. 3 shows the axial movement position of the work roll when rolling is performed by applying the method of the present invention in comparison with the cyclic movement position of the work roll according to the conventional method. At that time, in the method of the present invention, the arrival of the sheet crown-required material is detected in advance, and the direction of cyclic movement of the work roll during rolling of general materials is changed, so that the end of the work roll is changed when rolling the sheet crown-required material. The work roll position is set so as to be close to the width end of the rolled material. In addition, in the subsequent rolling of continuous plate crown required material, the above work roll setting position is used as the starting point.
The work roll is set to move cyclically with a small amplitude of 100 mm.

Note that in both the method of the present invention and the conventional method, the maximum movement position of the work roll differs depending on the width of the rolled material, but in these cases, the width end of the work roll is a certain distance from the body end of the work roll (here, This is because it is necessary to roll the material more than 50mm inside.

FIG. 4 shows the plate crown of a rolled material when the method of the present invention is applied, in comparison with the plate crown when rolled by the conventional method. The plate crown is defined by the difference in plate thickness between the center of the plate width and the 25 mm position from the edge of the plate width, and the target plate crown is indicated by a dashed line in the figure. As is clear from the figure, in the conventional method, the work roll is constantly moved in the axial direction with a large amplitude. The board crown has not been achieved. On the other hand, with the method of the present invention, plate crowns almost as desired were obtained with all materials.

Further, high spots in the rolled material due to abnormal wear of the rolls did not occur in either the method of the present invention or the conventional method.

In the above embodiment, an example of finish rolling of a hot strip mill was shown, but it goes without saying that the axially movable work roll can be placed on an appropriate stand, and the work roll can be moved easily. It goes without saying that the method of the present invention has similar effects in a rolling line for plate materials using a type rolling mill, which requires dispersion of work roll wear and control of plate crown and edge drop.

(Effects of the Invention) As detailed above, according to the present invention, the axial position of the work roll in the work roll moving rolling mill can be appropriately set according to the rolled material, and the rolling chance of the rolled material can be adjusted. without constraining the
It becomes possible to achieve both the effect of dispersing the wear of the work roll and the effect of controlling the plate crown and edge drop, and therefore greatly contributes to improving productivity, yield, etc.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram of a hot strip mill finishing stand with a moving work roll rolling mill, Fig. 2 is a diagram showing the strip width configuration of a rolled material in an embodiment of the present invention, and Fig. 3 is a diagram showing the above-mentioned implementation. Figure 4 is a diagram showing the plate crown of the rolled material obtained in the above example; Figure 5 is a schematic diagram of the wear profile of the work roll in a conventional four-high rolling mill. 6 are explanatory diagrams showing the relationship between the work roll setting position and the control range of the plate crown. 1-3...Conventional 4-high rolling mill, 4-7...Work roll moving rolling machine, 8...Conventional upper and lower work rolls, 9...Axially moving upper and lower work rolls,
10...Rolled material, 11...Plate crown meter.

Claims (1)

[Scope of Claims] 1. In a method of rolling a plate material by cyclically moving upper and lower work rolls in opposite directions along the axial direction each time a rolled material is rolled, the finished plate of each of a plurality of subsequent rolled materials. A work roll moving rolling mill characterized in that the cyclic movement pattern of the work roll during rolling is changed based on the information of thickness, strip width, target strip crown and/or target edge drop. Method of rolling plate material. 2. In the method described in claim 1,
The above information includes δmax, which is the maximum movable position of the work roll from the center of the mill, and S, which is the average moving amount or movable amount of the work roll during one rolling pass.
and when N ₀ is an integer such that N ₀ ≧ δmax/S,
A method that is information about each of the following N ₀ rolling stock. 3. In the method described in claim 2,
The maximum movable position of the work roll, which is the position of the work roll from the center of the mill and is determined from the width of the subsequent rolled material, is δ'max, and the average amount of movement or movable work roll of the work roll during one rolling pass is defined as δ'max. When the amount is S, the current moving position of the work roll from the center of the mill is δ _A , and the smallest integer greater than or equal to (δ′max − δ _A )/S is N, then If the required plate crown and/or edge drop is a severely rolled material, the direction of movement of the work rolls is set in the direction away from the center of the mill. 4. In the method described in claim 3,
When two or more sheets of rolled material with a severe required plate crown and/or edge drop are continuously rolled, starting from the work roll movement position δ'max, the required plate crown and/or edge drop is strictly required. A method of cyclically moving the work rolls with a movement amplitude smaller than the cyclic movement amplitude of the work rolls when continuously rolling a rolled material that has not been rolled.