JPS58218313A - Shape controlling device of material to be rolled - Google Patents

Abstract

PURPOSE:To improve effectively sheet crown and sheet shape, by detecting the surface shape of a sheet, and controlling the pressure of back-up rolls or a roll bender in accordance with a discriminating code corresponding to the detected shape. CONSTITUTION:Sheet crown or sheet shape is detected by incorporating a correcting rolling mill to the final stand of a tandem rolling mill and providing plural detectors 4 to the inlet or outlet side or to both sides of the mill. The detectors 4 are arranged in line in the width direction of a steel sheet S to be rolled to locate them at the central positions of respectively divided sections, divided into five equal sections for instance, in the direction of the sheet width, and the shapes corresponding to respective sections are detected to catch as a whole the distribution of the shapes in the width direction. The detected signals outputted from the detectors 4 are transmitted to a controlling device 5 in which several conditions concerning the sheet crowns and sheet shapes are set, and controlling signals for changing the quantity of crown of variable crown rolls 2 of the mill, basing on the detected signals and the set conditions, are outputted from the device 5. Further, the signals for controlling respective bending forces are transmitted to respective roll benders.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling the plate crown and plate shape of a rolled material. More specifically, the present invention applies to Japanese Patent Application No. 56-1131 already filed by the present applicant.
31 r Method for controlling plate crown and plate shape of rolled material"

In recent years, requirements for the accuracy of the plate crown and plate shape of rolled products such as rice have become stricter. In conventional rolling mills, the thickness in the longitudinal direction of the rolled material can be controlled with relative precision using an automatic thickness control device, but the thickness in the width direction is controlled by a roll bender, which makes it difficult to control the thickness. has its limits.

The initial crown attached to the roll expands upon receiving heat from the hot rolled material (hereinafter referred to as heat crown). Due to this heat crown, the roll crown changes with rolling time and saturates after a certain time.

As a result, it becomes impossible to control the plate crown and plate shape of the rolled material. To compensate for this, a roll bender is used, but in a normal quadruple rolling mill, the effect of the bender on modifying the plate crown and plate shape is small, and the heat crown cannot be sufficiently absorbed.

Therefore, rolling mills equipped with axially movable rolls and rolling mills equipped with variable clamp rolls were developed to replace roll benders and improve the precision of plate crowns and plate shapes. The former rolling mill controls the deflection of the work rolls by moving intermediate rolls of six stacked rolls in opposite directions in the axial direction. The latter rolling mill has a pressure receiving chamber between the roll arc and the IJ +p, supplies a pressure medium to this pressure receiving chamber, and controls the amount of crown of the roll by adjusting the pressure of the medium. It is.

For these reasons, the present inventors developed a roll that can control the amount of crown by adjusting the pressure of the pressure medium, and a roll that controls the amount of crown by applying a vertical load to both ends of the P-roll axis. Using a rolling mill equipped with a roll bender capable of
The above-mentioned Japanese Patent Application No. 56-113131 discloses a method of measuring one of the rolls and controlling the amount of crown of the roll based on the measured value and set rolling conditions.

The purpose of the present invention is to provide a concrete means for carrying out the technical idea of the prior application mentioned above, and to enhance the shape control effect by adding another function for shape modification. There is a particular thing.

The arrangement of the rolls of the rolling mill used to carry out the method of the invention and the active position of the roll benders are shown in FIG. 1, respectively. The rolling mill shown here is a four-layer rolling mill consisting of a work roll 1 and a backup roll 2, but other multi-layer rolling mills may be used. In this embodiment, the backup roll 2 is configured as a variable crown roll (hereinafter simply referred to as a VC roll).

The crown amount of the VC roll is controlled by supplying a pressure medium to a pressure receiving chamber 3 provided between the roll and the arm, and adjusting the pressure P' of the medium.

Furthermore, as shown in the figure, the roll bender usually includes a work roll bender BW, a backup roll bender BB,
There are decrease vendor BDs, etc.

The correction rolling mill 1o constructed in this manner is assembled into the final stand of the tandem mill F as shown in FIG. 2, and a control system as shown in FIG. 3 is constructed.

A plurality of detectors 4 are installed on the inlet side, the outlet side, or both sides of the rolling mill 10. In the embodiment shown in FIG. 3, a plurality of detectors 4 are installed only on the outlet side.
Please set up one. ), the plate crown detects the plate shape. The detectors 4 are arranged in alignment in the width direction of the steel plate S to be rolled, and are arranged at the center of each divided section where the width direction of the steel plate S is divided into five equal parts, for example, The eaves shape of the corresponding part is detected so that the axis of the shape in the board width direction can be determined as a whole.

The horizontal 1 signal from the detector 4 is sent to the control device 5. Various conditions related to the plate crown and plate shape, which will be described later, are set in the control device 5, and a control signal is sent to change the amount of crown of the v'G roll 2 of the rolling mill 10 based on the detection signal and the setting conditions. , and also sends a pending force control signal to each roll bender.

Each control signal is sent to the VC through a pressure controller 61 for operating the VC roll and a pressure controller 6j for operating each roll bender.
Directions are given to the roll and each roll vendor. With this control signal, the amount of crown of the VC roll can be freely changed even during rolling, and the pending force of each roll bender can also be changed at any time.

Now, in the method of the present invention, the shape in the board width direction is captured by a plurality of detectors 4 into five elements as shown in Fig. 4, and the results are compared with the following criteria to command i-positive. . The criteria for judgment are as follows.

1. Judgment is made based on the edge elongation i and the presence or absence of a downward peak at the edge of the sheet width.

11. The size of ear elongation is the difference between Dl- and Ul and D8
The difference between A and U2 is □.

111. Medium elongation is determined by whether the central part of the board width is lower than both adjacent parts.

lv, the magnitude of the medium elongation is the difference between the average value of the detector outputs at Ul and U2 and D2.

Originally, when comparing the correction effect of VC roll,
When the VC pressure (P) is kept large and the bender pressure (BW) is zero, the steepness is thick at the end, and when the VC pressure (P) is kept small and the bender pressure (BW) is applied, the steepness is thick. Steepness is effective for the central part, and this is also clear from the results shown in Figures 5 and 6.For this reason, it is more effective to use a roll bender to control the edge of the board width. It can also be seen that the use of VCC rolls is more effective for controlling the central part of the sheet width.

Taking such functional effects into consideration and comparing them with the above-mentioned criteria, the method of the present invention instructs the following modifications.

i, In the end shape correction method captured at +1 and +5 in Fig. 4, as a result of shape detection, the judgment code is 1 (ε
= 1x10-4) or more, the bender pressure is first actively used, and when the determination code becomes 1 or less, a command is given to continue to maintain the bender pressure.

ii. In the method of correcting the central part shape as shown in (2) to (4) in Fig. 4, if the judgment code is 1 or more, V
The variable crown amount is increased by increasing the C pressure, and when the determination code becomes 1 or less, a command is issued to continue to maintain the VC pressure at that point.

iii. Such operations are repeated to perform optimal shape control.

The method of the present invention can be applied to either a jingle stand rolling mill or a tandem stand continuous rolling mill, or a cold or hot rolling mill, and can effectively improve the plate crown and plate shape. It is possible to improve product quality and yield.

[Brief explanation of drawings]

FIG. 1 is a front view showing the roll arrangement of a rolling mill that implements the method of the present invention. FIG. 2 is a schematic diagram showing the arrangement of rolling mills. Third
The figure is a schematic configuration diagram showing the control system of the rolling mill. FIG. 4 is a diagram for judgment showing the shape detection results in the board width direction divided into five parts. 5 and 6 are diagrams showing the steepness of various rolling examples performed in the rolling mill used in the present invention. 1: Work roll 2: Backup roll (VC roll) 4: Detector
5: Control device 6: Pressure controller 1o: Rolling machine S: Steel plate

Claims (1)

[Claims] A tandem mill is a rolling mill equipped with a backup roll that can control the amount of crown by adjusting the pressure of the pressure medium and a roll bender that can control the amount of crown by applying a vertical load to both ends of the roll axis. The surface shape of the board is detected by dividing the board width direction into multiple parts on the exit side of the final stand, and the detection code is determined in advance according to the shape distribution state in the board width direction. A method for controlling the shape of a rolled material, comprising controlling the pressure of a coated up roll or a roll bender based on the corresponding judgment.