JPS60196216A - Method for controlling plate thickness in tandem rolling mill - Google Patents

Abstract

PURPOSE:To control plate thickness without making control between stands and draft setting intricate by setting roll gaps and making the rolling reduction of the lowermost stand zero so that the plate thickness on the outlet side of the (n-1)th stand attains target plate thickness. CONSTITUTION:Screw down devices 3e-3a are so set by a roll gap control device 1 that the plate thickness on the outlet side of a rolling mill 4b attains the target plate thickness after a change in the stage of tandem rolling by rolling mills 4a-4e. The length of a rolling material is measured by an arithmetic unit 6a for the length of the rolling material and the device 3a is moved to make the rolling reduction of the stand 4a zero so that the rolling load on the operating side of the stand 4a and the rolling load on the counter operating side, measured by a rolling load detector 2a, are made equal when the desired change point of the plate thickness arrives at the mill 4a. The speed reference taking into the forward slip of the mill 4b into consideration is calculated by an arithmetic unit 9 for speed and is outputted to a speed control device 7. The load is dispersed to the mills 4b-4c by draft control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for controlling a sheet J height in a tandem rolling mill.

“Technical background of the invention and its problems] In general, in a rolling mill with multiple stands, the method of changing the rolled material plate from A to B at the exit side of the most downstream stand is as follows:
Change the reduction amount at the first stand on the entry side of the rolling mill at the thickness change point of the rolled material, and then change the reduction amount ゛ when the thickness change point of this rolled material is reached at the second stand. do. 1) Control was performed to change the plate thickness at the exit side of the most downstream stand from A to B by tracking the change points toward the primary downstream stand and changing the rolling reduction amount. however,
According to this method, since the plate thickness is changed from the first stand of the rolling mill, the point at which the plate thickness changes must be accurately tracked.
For looperless control and mass 70-control, the rolled material before the thickness change, 'M, the rolled material during the thickness change, and the rolled material after the thickness change must be taken into consideration, which is very complicated. It has become. That is, when controlling one rolled material, it is necessary to consider the control of two rolled materials with different dimensions, and the setting values of each stand and the switching timing of control signals are extremely complicated. There is. In addition, it is necessary to accurately track and control the plate thickness change point at each stand, and plate thickness change control is a very complicated control method.0 [Object of the Invention] The present invention has been developed in view of the above circumstances. As a result, the downstream products are reduced to 'zero' at the final stand of the tandem rolling mill. In particular, by changing the plate thickness at the exit side of the final stand, we have developed a plate thickness control method in a tandem rolling mill that allows rolling to be performed without complicated control of the looper, looperless, mass flow control, and reduction setting control on the upstream side. The purpose is to provide.

[Summary of the Invention] In tandem rolling using a plurality of rolling mills, the plate thickness at the exit side of the final stand is changed by setting the rolling reduction amount of the final stand to zero. @In order to prevent the rolled material from meandering when zeroing the final stand, the rolling load on the operation side of the stand and 1
The rolling device of the stand is controlled so that the values of the rolling loads on the opposite operation side are equal, and the rolling amount is set to zero. At this time, the tension between the reading stand and the stand one stand upstream from the stand (hereinafter referred to as the n-1 stand) is eliminated, so the load on each stand is balanced and the downstream table of the stand is moved at the stand speed. Rolling is continued while changing the thickness of the rolled material by setting the speed standard taking into account the advance rate of n-1 stands from the standard.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawing is a block diagram of the mechanical configuration of the tandem rolling mill and its control device. Rolled material 8 moving in the direction of the arrow
When the roll is tandem rolled by the machines 43 to 4e to a pressure with a roll gap control device of 1, the reduction devices 3e to 3a are rolled so that the thickness at the exit side of the rolling mill 4b becomes the target thickness after changing the thickness. Set using the gap control device 1. In this state, the rolled material 8 is rolled, and the length of the rolled material is measured by the rolled material length calculation device 6a. When the desired plate thickness change point reaches the rolling mill 4a, the rolling load detector 2a detects the length of the rolled material on the operation side of this stand 4a. rolling load and
The roll-down device 3a is moved by the roll "gap control device" so that the values of the rolling loads on the opposite operation side become equal, and the rolling amount of this stand is set to zero. At this time, the rolling load detector 2a detects that the rolled material 8 is on this stand. When it is detected that the speed of the rolling mill 4b has run out, the speed calculation device 9 changes the speed of the rolling mill 4b using the speed reference of the rolling mill outlet equipment 10, which was driven in synchronization with the speed reference of the rolling mill 4a, as the speed reference of the rolling mill 4b. A speed standard is calculated in consideration of the ratio and output to the speed control device f7.Also, since the rolling reduction amount of the rolling mill 4a becomes zero, the tension between the stands between the rolling mills 4b and 4a becomes zero, so the rolling mill 4b The load torque of the rolling mills 41) to 4e increases compared to the conventional method. Therefore, by controlling the rolling mills 40 to 4e on the upstream side, the load is distributed to each of the rolling mills 41) to 4e, and the load is balanced.

[Effects of the Invention] As explained above, according to the present invention, the thickness change of the same rolled material at the exit side of the final stand in a tandem rolling mill using a plurality of stands can be controlled and The reduction setting of each stand can be made without complication.

[Brief explanation of the drawing]

The drawing is a block diagram of the mechanical configuration of the tandem rolling mill and its control device. 1... Roll gap control device 28-2C... Rolling load detector 38-3e... Rolling device 4a-4e... Rolling mill 6
8~6C...Rolled material length calculation device

Claims (1)

[Claims] In a tandem rolling mill in which multiple stands are equipped with a roll gap control device and a roll speed control device, the roll gap that makes the outlet side plate thickness of the stand located one stand upstream from the most downstream the target plate thickness after changing the plate thickness. The rolling amount of the stand located at the most downstream is reduced so that the operating side rolling load and the counter-operating side rolling load of the stand are constant, and the rolling amount of the stand is reduced to zero. The rolled material is reduced by adjusting the load balance of the stand located upstream of the stand and the speed of the table located downstream of the stand, which occurs when the rolling reduction amount of the stand becomes zero. A method for controlling plate thickness in a tandem rolling mill, the method comprising changing the plate thickness at the lowest outlet side of a tandem rolling mill.