JPH02117709A - Method for controlling sheet thickness in rolling mill - Google Patents

Abstract

PURPOSE:To perform gap control with high accuracy and to improve sheet thickness accuracy by setting a mill constant based on a rolling load, backup roll bending amount, and roll shift amount as parameters and performing sheet thickness control in a rolling mill. CONSTITUTION:A rolling load detector 5 detects a load P, a backup roll bending amount detector 6 detects a bending amount beta, a roll shift amount detector 7 detects a shift amount alpha. A mill constant computing part 8 calculates a mill constant M' by use of the above three amounts as parameters. A roll gap narrowing amount computing part 10 calculates a narrowing amount s and a roll drafting device 4 controls a roll gap through a roll gap commander 11. Gap control is performable with high accuracy and sheet thickness accuracy is improved by considering variable amounts in the constant M' caused by the backup roll bending amount beta and roll shift amount alpha.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for controlling plate thickness in a cold multi-high rolling mill.

(Prior Art) Cold multi-high rolling mills are widely used for rolling electronic materials and the like.

In a rolling mill, it is important to control the thickness of a rolled plate to maintain a constant thickness, and the following method is adopted as one of the methods for controlling the plate thickness in a cold multi-high rolling mill.

This sheet thickness control method involves knowing the rolling load that changes due to changes in the thickness of the sheet material on the entry side of the work rolls, and correcting the gap between the work rolls in proportion to that signal. In other words, the plate material with the entrance side thickness h1 is placed in the roll gap S
The sheet is passed between work rolls and rolled at a rolling load P to a sheet thickness h2 on the exit side. Here, when the inlet side plate thickness h1 of the plate material changes, the outlet side plate thickness h2 also changes. Further, the rolling load P and the roll gap S change. Therefore, by detecting the change ΔP in the rolling load P and tightening the roll gap S by the change ΔS based on this change ΔP, the exit side plate thickness is returned to the original h2 and the exit side deviation is made zero. be able to.

The roll gap tightening amount of the work roll is calculated by dividing the rolling load change ΔP caused by plate thickness variation by the mill constant M of the rolling mill.

Expressing this in a formula, ΔS - ΔP/M.

(Problem to be solved by the invention) Such a plate thickness control method is considered to be highly accurate and has been adopted, but when implemented in a cold multi-roll mill, it is still difficult to maintain a constant thickness at the exit side of the plate. The accuracy may be insufficient to maintain the

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a method for controlling the thickness of a rolling mill, which can control the thickness of a rolling mill with high precision.

[Structure of the Invention] (Means and Effects for Solving the Problem) The inventor of the present invention knows the rolling load that changes due to changes in the plate thickness on the entry side of the work roll, and adjusts the gap of the work roll according to the change. Various studies have been conducted on the modified plate thickness control method.

In this sheet thickness control method, the roll gap tightness limit is determined by dividing the change in rolling load by a mill constant, and the inventor conducted research using special number 11L of this mill constant.

As a result, the mill constant is the ratio between the rolling load and the resulting displacement, but in reality, the amount of backup roll bending and roll shift amount in the rolling mill during rolling acts, and the amount of backup roll bending and roll shift amount is Findings 1. When , the Mill constant changes in proportion to the amount of change. Ta.

Backup roll bending is a process in which the up roll partially suppresses the work roll to correct the deflection of the board. Roll shift!・Corrects the deflection of the plate material by moving at least one of the work roll or backup roll in the axial direction.

These methods apply pressure to the plate material in order to control the thickness and shape of the plate material, and these conditions combine to affect the mill constant. As a result, the Mill constant changes. Therefore, when calculating the tightening amount of the roll gap by dividing the change in rolling load due to plate thickness variation on the entry side by the mill constant, add the backup roll bending amount and roll shift amount as parameters as described above. By using dynamic mill constants, it is possible to calculate the accurate tightening amount (correction amount) of the roll gap in accordance with the actual rolling conditions, and this allows for accurate strip thickness control on the exit side. It turns out that it can be done.

The mill constant M' obtained from this knowledge is expressed as M'-5(P·α·β), where P10 is the rolling load, α is the rolling amount, and β is the roll shift amount.

Also, the roll gap △S obtained using this Mill constant
is expressed as ΔS-ΔP/M'.

On the other hand, conventional mill constants do not take backup roll bending and roll shift into account as characteristics of mill constants, and use static mill constants, making it difficult to calculate an accurate roll gap in line with actual rolling. This made it impossible to accurately control the thickness of the work roll exit side.

The present invention has been made based on these findings.

That is, the plate thickness control method for a rolling mill according to the present invention detects a change in rolling load that changes due to changes in the thickness of a plate material on the entry side of a work roll in a rolling mill, and detects a change in rolling load that changes due to a change in the thickness of a plate material on the entry side of a work roll in a rolling mill. In the method of calculating the amount of roll tightening of a work roll by dividing by a constant, the mill constant is characterized by setting the rolling load, the amount of backup roll bending, and the amount of roll shift as parameters.

(Example) In an example of the plate thickness control method of the present invention, the first rolling mill is a cold multi-high rolling mill. The drawing schematically shows a rolling mill, and shows work rolls 2, 2 through which the plate material 1 passes, backup rolls 3, 3, a roll reduction device 4, and a rolling load detector 5 using a load cell and the like.

During rolling, the plate material 1 with the entry side thickness h1 is passed between the work rolls 2.2 of the roll gap S, and the plate material 1 before rolling is IIfP.
Pressure is applied to the plate and rolled to a thickness h2 on the exit side. Inlet side plate thickness h of plate material 1
1 changes, the outlet side plate thickness h2 changes. Further, the rolling load P and the roll gap S also change. Therefore, the tightening amount △S of the roll gap is determined according to the change △P in i'rCP before rolling, and the gap of the work roll 2.2 is adjusted using this △S to keep the outlet plate pressure h2 constant. Control as follows.

When performing this control, the rolling load detector 5 detects the rolling load P before the change. Further, the backup roll bending output unit 6 detects the bending amount β of the backup roll 3, and the roll shift amount detector 7 detects the shift amount α of the work roll 1, for example. and,
The signals output from each of these detectors 5.6.7 are sent to the mill constant calculation section 8, and then to the rolling load change detection section 9, which detects the change ΔP in the rolling load P due to the change in the entrance side plate thickness h1 of the plate material 1. . Then, the roll gap tightening amount calculation unit 10 receives the mill constant M' and the rolling load variation ΔP, and calculates the tightening amount ΔS of the work roll gap S based on the formula ΔS-ΔP/M'. The calculated tightening amount △S is sent to the command unit 11.
through the roll-down device 4, which device 4 serves as a work roll].

1 and backup rolls 2, 2 are moved and the roll gap is tightened by a tightening amount ΔS.

By this tightening, the outlet side plate pressure h2 of the work roll 1.1 can be returned to the original thickness and kept constant.

[Effects of the Invention] As explained above, according to the method for controlling plate thickness of a rolling mill of the present invention, by taking in changes in the mill constant due to the amount of backup roll bending and the amount of roll shift,
By controlling the roll gear with high precision, it is possible to precisely control the thickness of the plate material.

[Brief explanation of the drawing]

FIG. 1 is a functional configuration diagram showing an embodiment of the method of the present invention. ]... Plate material, 2, 2... Work roll, 3, 3...
Bank up roll, 4... Roll pressure r device, 5...
・Rolling load detector.

Claims (1)

[Claims] A device that detects the change in rolling load that changes due to changes in the thickness of the plate material on the entry side of the work roll, and calculates the amount of roll gap tightening in the work roll by dividing this change in rolling load by a mill constant. A method for controlling plate thickness in a rolling mill, characterized in that the mill constant is set using a rolling load, a backup roll bending amount, and a roll shift amount as parameters.