JPS61119314A - Control method of plate crown - Google Patents

Abstract

PURPOSE:To obtain the plate stock to which a fixed plate thickness and plate crown are given by measuring a rolled plate crown and by changing the rotary speed ratio of the upper and lower work rolls and roll opening corresponding to the measured value thereof. CONSTITUTION:A control device 16 sets in advance on each rolling conditions the relation of a target plate crown and rolling load and the relation of the rolling load and the rotary speed ratio of the upper and lower work rolls 11A, 11B. The necessary rolling load for obtaining the prescribed target crown is found at the outside of the rolling mill and the necessary roll opening for rolling the plate stock is set based on the rolling load and target plate thickness at outlet side. The rotary speed ratio of the upper and lower work rolls 11A, 11B to satisfy the rolling load and roll opening are set as well, by which each driving motor 12A, 12B is controlled and a plate stock 17 is rolled.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for controlling the crown of a plate during rolling of a plate.

[Prior Art] As a conventional sheet crown control method, there is a method of changing the distribution of the reduction amount between the front stand and the rear stand in tandem rolling. This is because when rolling with a tamp, the final plate crown is determined by the rolling conditions at the later stand, especially the rolling load.
This method attempts to obtain the target sheet crown by changing the rolling reduction distribution and changing the rolling load on the rear stand.

[Problems to be Solved by the Invention] However, in the above conventional method, it is not possible to control the plate crown during rolling, that is, to change the reduction distribution, and it is not possible to control the plate crown during rolling, and it is not possible to change the rolling distribution uniformly over the entire length of one rolled coil. Obtaining a plate crown is difficult. Further, the above conventional method is based on tandem rolling, and it is impossible to control the plate crown on a stand.

An object of the present invention is to obtain a plate material having a constant plate thickness and a constant plate crown.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for controlling the crown of a plate when rolling a plate by a rolling mill in which the rotational speed of upper and lower work rolls is variable, comprising: The relationship between the target plate crown and the rolling load, and the relationship between the rolling load and the rotational speed ratio of the upper and lower work rolls are determined in advance for each rolling condition, and the rolling load necessary to obtain the specified target plate crown at the exit side of the rolling mill is calculated. and setting the roll opening necessary for rolling the plate based on the rolling load and the target exit plate thickness, and setting the rotation speed ratio of the upper and lower work rolls that satisfies the rolling load and the roll opening, It is designed to roll plate materials.

[Function] The relationship between the plate crown after rolling the plate material and the rolling load can be shown by a -wood curve. As an example, Fig. 2 shows the relationship between the exit side sheet crown and the rolling load when only the rolling load is changed without changing the entrance side sheet thickness, rolling reduction, and sheet width. By changing only the rolling load under certain conditions, it is possible to change the plate crown after rolling.

Further, the rolling load can be changed by changing the rotational speed ratio of the upper and lower work rolls without changing other rolling conditions. Figure 3 shows the upper and lower work rolls when only the rotation speed ratio of the upper and lower work rolls (faster roll speed/slower roll speed) is changed while keeping the plate speed at the exit side of the rolling mill constant. The relationship between the rotational speed ratio of the work roll and the rolling load is shown, and it is observed that the rolling load decreases as the rotational speed ratio increases, forming a single curve.

In other words, the relationship between the rolling load and the plate crown, the rotational speed ratio of the upper and lower work rolls, and the rolling load is determined in advance according to each rolling condition, and the plate crown rolled during rolling is measured, and the relationship between the rolled plate crown and the rolling load is determined in advance. By changing the rotational speed ratio of the upper and lower work rolls and the roll opening degree, it is possible to obtain a plate material having a constant plate thickness and a constant plate crown over the entire length of the wooden coil.

[Example] FIG. 1 is a control system diagram of a rolling mill used in an example of the present invention. IIA and IIB are upper and lower work rolls, each work roll IIA.

11B each have their drive motors 12A, 12
By the drive control of B, it is possible to drive at mutually independent rotational speeds. 13 is a reduction device, 14 is a load cell,
15 is a plate crown measuring device. 16 is a control device, and the control device 16 controls the relationship between the target plate crown and the rolling load;
The relationship between the rolling load and the rotational speed ratio of the upper and lower work rolls ILA and IIB is determined in advance for each rolling condition, the rolling load necessary to obtain a predetermined target sheet crown on the exit side of the rolling mill is determined, and the relationship between the rolling load and the rotation speed ratio is determined in advance for each rolling condition. The roll opening necessary for rolling the plate material is set based on the target exit plate thickness, and the upper and lower work rolls IIA and IIB satisfy the rolling load and roll opening.
, thereby setting the rotational speed ratio of each drive motor 12.
A and 12B are driven and controlled so that the plate material 17 can be rolled.

Hereinafter, implementation of a concrete plate crown control method by the control device 16 will be described.

First, before rolling the plate material, the control device 16 determines the roll opening degree and the rotational speed ratio of the -L lower work rolls IIA and 11B necessary for rolling the plate material with the target plate crown. How to obtain this will be explained with reference to FIG. That is,
From the relationship between the rolling load and the plate crown as shown in Figure 2, the rolling load F1 required to form the target plate crown is determined. Next, the point P1 consisting of the exit target plate thickness T1 and the target rolling load F1 is gauged. Find the roll opening S that allows meter 2 G to pass through. Further, the rotational speed ratio of the first lower work roll 11A and IIB necessary for making the plastic curve of the material pass through the point Pi is determined from the relationship between the rolling load and the rotational speed ratio as shown in FIG. TO is the entrance side plate thickness. The roll opening degree S obtained in this way and the upper and lower work rolls IIA, I
Setting the rotation speed ratio of IB Next, measure the actual rolling load with the load cell 14 during rolling, and if the actual rolling load differs from the target rolling load, set the rotation speed ratio while checking the value of the load cell 14. is corrected and controlled to achieve the required rolling load.

Next, when the entrance plate thickness To differs from the expectation and the entrance plate thickness TOA changes to a larger entrance plate thickness TOH as shown in Fig. 5, the intersection of the gauge meter equation G and the plastic curve is at point P to point P2. Therefore, by changing the rotational speed ratio of the upper and lower work rolls IIA and LIB, the plasticity curve LA
The slope of is changed to LB shown by a solid line so that the gauge meter formula G and the plasticity curve LB intersect at the target point PL.

In this case, the load cell 14 is
While checking the load, change the rotational speed ratio of the upper and lower work rolls IIA and IIB so that it matches the target.

Next, the plate crown on the exit side is measured using the plate crown measuring device 15. Here, even though the actual rolling load matches the target rolling load, the measured sheet crown is a reflection of the roll's condition! It may be different. In that case, the load correction amount ΔF necessary to correct the difference in plate crown is determined from the difference in plate crown with respect to the target based on the relationship between rolling load and plate crown. As shown in Figure 6, the load correction amount is Δ
F, the correction amount ΔS of the roll opening degree S is ΔS=
ΔF/K (K is the slope of the gauge meter type 〇), and the rolling load after correction and the upper and lower work rolls IIA, II
It is possible to determine the amount of change in the rotation speed ratio from the relationship between the rotation speed ratios of B.

GC is a gauge meter type after correction, and LC is a plasticity curve after correction.

[Effects of the Invention] As described above, the present invention provides a plate crown control method when rolling a plate material by a rolling mill in which the rotational speed of the upper and lower work rolls is freely variable, and the method includes controlling the relationship between the target plate crown and the rolling load. , and the relationship between the rolling load and the rotational speed ratio of the upper and lower work rolls are determined in advance for each rolling condition, the rolling load required to obtain a predetermined target plate crown on the exit side of the rolling mill is determined, and the rolling load and the target output are determined in advance. The roll opening necessary for rolling the plate material is set based on the side plate thickness, and the rotation speed ratio of the upper and lower work rolls that satisfies the rolling load and roll opening degree is set to roll the plate material. It is. Therefore, by changing the rotation speed ratio of the upper and lower work rolls and the roll opening degree, it is possible to obtain a plate material having a constant plate thickness and a plate crown over the entire length of the wood coil.

[Brief explanation of drawings]

Fig. 1 is a control system diagram of the rolling equipment used to carry out the present invention, Fig. 2 is a diagram showing the relationship between rolling load and plate crown, and Fig. 3 is a diagram showing the relationship between upper and lower roll rotational speed ratios and rolling load. Figure 4 is a diagram showing the relationship between roll opening degree and rolling load, and Figure 5 is a diagram showing the relationship between roll rvLt and rolling load when changing the rotation speed ratio when the entry side plate thickness is different. The diagram shown in FIG. 6 is a diagram showing the relationship between the roll opening degree and the rolling load when changing the roll opening degree correction and rotational speed ratio in order to perform load correction. 11A, LIB...work roll, 12A, 12B...
... Drive motor, 13... Reduction device, 15... Plate crown measuring device, 16... Control device, 17... Plate material. Agent Patent Attorney Osamu Shiokawa 1 Figure 2 Figure 2 Figure 1 (to^) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A plate crown control method when rolling a plate material by a rolling mill in which the rotational speed of the upper and lower work rolls is variable, and the relationship between the target plate crown and rolling load, and the rolling load and the rotational speed of the upper and lower work rolls. The ratio relationship is determined in advance for each rolling condition, the rolling load required to obtain a predetermined target plate crown on the exit side of the rolling machine is determined, and the rolling load necessary to roll the plate material is determined based on the rolling load and the target plate thickness on the exit side. A plate crown control method for rolling a plate by setting a roll opening degree and setting a rotation speed ratio of upper and lower work rolls that satisfies the rolling load and roll opening degree.