JPS63235011A - Control method for sheet shape in rolling mill - Google Patents

Abstract

PURPOSE:To optimally control the sheet shape by estimating a heat crown development amount of the preceding rolled stock and finding a work roll bending correction amount for the present rolled stock to obtain a combined value with an optimum work roll bending force. CONSTITUTION:A difference WRB1 between a work roll bending force WRB1E immediately before rolling finish of the preceding rolled stock and an optimum work roll bending force WRB1<i> when no heat crown develops on work rolls 12, 12' is found. The difference WRB1 is inputted to a work roll bending correction amount converter 18 and is converted into a work roll bending correction amount WRB2 by use of a rolling condition for the present rolled stock. Then, a combined value WRB2 of the correction amount WRB2 and an optimum work roll bending force when no heat crown develops on the rolls 12, 12' and the combined value WRB2 is presetted in a work roll bending controller 16. Thus, a bending device 14 offers a bending force to optimally control a sheet shape.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the shape of a strip in a rolling mill, which presets a work roll bending force that optimizes the shape of the strip when passing a rolled material.

(Prior art) In general, the heat crown of a work roll, which is one of the factors that has a large influence on the shape of a rolled material in order to control the shape of the rolled material during the rolling process, integrates the amount of heat received by the work roll from time to time. The work roll crown is calculated by combining the heat crown predicted in this way and the initial crown of the work roll before rolling, and the sheet width, which is another factor that affects the sheet shape. The relationship between the work roll bending force and the optimal plate shape on the exit side of the rolling mill was experimentally determined based on the rolling conditions such as the plate thickness of 1 alloy and the rolling blade.

The work roll bending force determined in this manner is preset.

However, with this method, the heat crown of the work roll, which changes from moment to moment, must be constantly predicted based on a certain experimental formula, which makes control complicated, and it is difficult to accurately predict the heat crown. Therefore, there was a drawback that the plate shape of the rolled material could not be well controlled.

(Objective of the Invention) The present invention [1] is a rolling mill plate that eliminates the need to constantly predict the ever-changing heat crown of the work roll and allows optimal control of the plate shape of the rolled material. The object of the present invention is to provide a shape control method.

(Composition of Development I'll) The method for controlling the plate shape of a rolling mill of the present invention is to control the plate shape of a rolled material in a rolling mill in which a pair of work rolls is provided with a work roll bending device. The amount of heat crown growth is estimated from the difference between the work bending force just before the end of rolling of the rolled material and the optimal work bending force when no heat crown has grown on the work roll, and from this amount of heat crown growth, the Find the work roll benzo ink correction amount under the rolling conditions, find the composite value of this work roll benzo ink correction 1 and the optimal work roll bending force when no heat crown has grown on the work roll, and calculate the composite value of this work roll benzo ink correction amount. It is characterized by controlling the plate shape of the rolled material by presetting the optimal work roll bending force for the rolled material.

According to this method, the influence of heat crown on the work roll is the difference between the work roll bending force just before the end of rolling of the previous rolled material and the optimal work roll bending force when no heat crown has grown on the work roll. As a result, the heat crown of the work rolls, which changes from moment to moment, can be bundled directly without the need to constantly predict the heat crown of the work rolls from the amount of can be well controlled.

(Example) An example of the present invention will be described in detail with reference to the drawings. Figure 9 systematically shows an apparatus for implementing the method for controlling the plate shape of a rolling mill according to the present invention. The rolling mill 10 includes a pair of work rolls 12.12° (not shown) for rolling a rolled material, and a work roll bending device 14 provided on these work rolls 12.12° to control the plate shape of the rolled material. There is. The work roll bending device 2114 transfers the work roll bending force received from the work roll bending control device 16 to the work roll 12 in a later manner.
, 12° to control the rolled material into an optimal plate shape.

As shown in FIG. 9, the method of the present invention is to control the plate shape of a rolled material in a rolling mill IO by adjusting the work bending roll angle WRBI' and the work rolls 12 and 12 degrees just before the end of rolling of the previous rolled material. Difference ΔWR from the optimal work bending force WRB1' when the heat crown has not grown
Find Bl. Heat crown or Jji on the work roll
, the optimum work roll bending force when IZ is not applied is stored in advance for each rolling condition such as various alloys, sheet widths, sheet thicknesses, rolling reductions, etc. The difference △W found in this way
RBI corresponds to the influence due to the heat crown of the work roll. In the present invention, this difference ΔWRB1 is supplied to the work roll bending correction amount converter 18, and the converter 18 converts this difference ΔWRBI into the current rolling. The work roll bending correction amount ΔWRB2 of the currently rolled material is determined by converting the rolling conditions of the material. Next, this work roll bending correction amount ΔWRB2 is combined with WRB21 to obtain the optimum work roll bending force when no heat crown has grown at 12.12° of the work roll (4WRB2 is obtained, and this combined value WRB2 is the value for the current rolled material. The optimal work roll bending force is preset in the work roll bending control bag 2116. In this way, the work roll bending force WRB2 or the work roll benzo ink control device is always set to the work roll bending force that is most suitable for the plate shape of the rolled material to be currently rolled. 16, the work roll bending device 14 can apply a pending force tF to the work rolls to optimally control the plate shape of the rolled material.

In general, the major factors that determine work roll bending are the deflection of the work roll due to downstream blades and the heat crown of the work roll. The influence of deflection of the roll due to the reduction blade is determined by storing the standard value of the optimum work roll bending radius in advance for each rolling condition such as alloy, sheet width, sheet thickness, downstream (pe, etc.) when no heat crown has grown on the work roll. This is taken into account by extracting and using this standard value for each rolling condition.On the other hand, as already mentioned, the influence of the heat crown of the work roll is ΔW.
It is considered in RBI and ΔWRB2. Therefore, by processing as described above, it is possible to provide the work roll bending surface WRB2 to the work rolls 12 and 12' so as to control the rolled material into the optimal plate shape.

In addition, in the present invention, in order to improve the accuracy of the work roll bending hook brisser toy 1, the optimum work roll bending hook standard 1 and work roll bending correction amount conversion when no heat crown has grown on the work roll. It is preferable to provide the device 18 with a learning device to correct the work roll bending force as needed. Furthermore, although the above embodiments have been described regarding a rolling mill having only a work roll bending device, this rolling mill can also be applied to a rolling mill having a device for moving rolls in the axial direction or a variable crown backup roll. Something comes up.

(Effects of the Invention) According to the present invention, the heat crown of the work roll, which changes from moment to moment as described above, can be easily determined from the amount of heat without the need to predict the temperature. There is a practical benefit to being able to better control the shape of the rolled material by presetting the hook.

[Brief explanation of drawings]

The drawing is a schematic system diagram of an embodiment of the method for controlling the plate shape of a rolling mill according to the present invention. 10-----1 rolling mill, 12,12''--work roll, 14-----work roll bending device, 16-----work roll bending; UVa device, 18-- --Work roll bending correction amount converter.

Claims (1)

[Claims] When controlling the plate shape of a rolled material in a rolling mill that has at least a work roll bending device, the work bending roll force immediately before the end of rolling of the previous rolled material and the optimal work bending when no heat crown has grown on the work roll are determined. The heat crown growth amount is estimated from the difference between the heat crown growth amount and the work roll bending correction amount under the rolling conditions of the current rolled material.
By calculating the composite value of this work roll bending correction amount and the optimal work roll bending force when no heat crown has grown on the work roll, and presetting the composite value as the optimal work roll bending force for the current rolled material. A method for controlling a plate shape of a rolling mill, the method comprising controlling the plate shape of a rolled material.