JPS58196112A - Controlling device of sheet thickness in rolling mill - Google Patents

Abstract

PURPOSE:To provide a titled device capable of changing the sheet thickness during rolling and keeping the excellently accurate sheet thickness, by constituting a controlling system of roll gap by inputting the reference value of tapered sheet thickness at the exit side as well as inputting the gauge-meter sheet thickness as a feedback signal. CONSTITUTION:The gauge-meter sheet thickness (hg) is calculated with a calculating device 25 of the plate depth basing on a rolling load P and a roll gap So detected respectively by a load detector 23 and a draft position detector 24 of a rolling roll 1 used for rolling a material 2 to be rolled. On the other hand, a function generator 10, which inputs a position signal of a speed detector 22 of a motor 20 used for driving the rolling roll 1, outputs the reference value href (l) of the tapered sheet thickness at the exit side corresponding to the draft position of the material 2. The difference between said output signal and the (hg) mentioned above is calculated by a subtractor 26 and a integrator 13, and the result is added, by an adder 27, to the changing quantity of the reference value obtained by an arithmetic device B, which is used for calculating the changing quantity of the sheet thickness reference value, and consisting of a memory device 11, a subtractor 28, and a multiplier 9, and then, the added result is outputted to a hydraulic-reduction controlling device 14 to control a roll gap.

Description

[Detailed description of the invention] (Otori) Description of the technical field The present invention is designed to continuously roll two or more products with different thicknesses from a single O-rolled material in a rolling mill that rolls steel plates, etc. The present invention relates to a plate thickness control device for a rolling mill used for modified rolling.

-) Description of the prior art In recent years, rolling mills that roll steel plate rings have been developed to automatically change the plate thickness and continuously roll products with two or more different thicknesses from one rolled material. Modified piezoelectricity is expected to dramatically improve production efficiency on production lines for high-mix, low-volume production.

1%, the thickness of steel plates used in spherical tanks for storing liquefied natural gas (LNG) is not uniform, and due to the difference in internal pressure between the lower and upper parts of the tank, a steel plate with a thicker plate at the bottom is required. ing.

As an example of sheet thickness changing rolling, consider the case where a product having a flat sheet thickness is rolled into a product having a tapered sheet thickness shape as shown in FIG. 1 in a jingle stand hot rolling mill.

Conventional rolling methods for this plate thickness variation V include the methods shown in FIGS. 82 and 3.

The method shown in FIG.
- Predictively calculate the roll df jump setting value using a mathematical model, and set the roll gap reference value goref of the rolling position control device 3 when the changing position of the rolled material 2 passes directly under the rolling roll l during rolling. , a rolling method in which the roll gap setting value before the sheet thickness change is tapered to the roll gap setting value after the change, and when the roll gap of the rolling roll 10 is operated by the rolling position control device 3, the sheet change is changed from K. It is.

When changing the plate thickness using this method, the accuracy of predicting the rolling load and roll gap calculated using a mathematical model will directly affect the accuracy of the plate thickness.

41. In hot rolling, the plate thickness is not uniform, so the cooling conditions for the plate temperature are different, and it is dangerous if the plate temperature is uniform. Therefore, it is important to predict the temperature of the material, which determines the magnitude of the material's deformation resistance. pIn order to increase the prediction accuracy, create a complex mathematical model,
Accurate adjustment of material temperature using a thermometer is required, which requires a great deal of expense and labor.

Further, the method shown in FIG. 3 is rolling with nine thickness changes using an automatic thickness control system using a feedback signal from a thickness gauge. In this method, a rolled material 2 is conveyed to a rolling mill and a rolling roll I
Until the plate thickness meter 6 installed on the exit side of the K-bit rolling machine is reached, the automatic plate thickness control is turned OFF and rolling is performed using the roll gap setting value before the plate thickness change, so that the rolled material 2 has a plate thickness. Total 6
After reaching , automatic plate thickness control is turned on and plate thickness change rolling is started, and the changed position of the rolled material 2 is tracked.

If it is determined by the above tracking that the changed position passes through the rolling roll 1, the automatic plate thickness control device changes the plate thickness reference horef in a tapered shape from the target plate thickness before the plate thickness change to the target plate thickness after the change. 5 and the lowering position control device 3,
This is plate thickness changing rolling in which the roll gap of the rolling rolls 1 is manipulated so that the deviation between the plate thickness reference horef and the actual plate thickness detected by the plate thickness meter becomes zero at the subtractor 4.

However, in this case, since the plate thickness needle 6 is located away from the rolling mill, there is a delay in the detection response of the plate thickness needle 6.

Therefore, when performing plate thickness changing rolling using the method shown in FIG. 3, a product with good plate thickness accuracy cannot be rolled unless the delay in detection response of the plate thickness meter 6 is taken into consideration.

(C) Purpose of the Invention The present invention was developed in view of the above circumstances, and it is possible to change the thickness of a rolled material without considering the material, hardness, pass schedule, or lubrication condition of the rolling mill. The object of the present invention is to provide a plate thickness control device for a rolling mill that allows for good rolling.

(d) Structure of the Invention The present invention provides an automatic plate that provides a tapered plate thickness standard to a hydraulic reduction control device and uses a gauge meter plate thickness calculated using a roll gap detection value and a rolling load detection value as a feedback signal. The exit side plate thickness is corrected by changing the plate thickness standard of the thickness control device (hereinafter referred to as AGC).

FIG. 4 is a block diagram when the present invention is applied to a rolling mill equipped with a hydraulic reduction control device, and is an example in which the output side plate thickness is corrected by operating the roll gap using the output of the AGC device.

Hereinafter, the present invention will be explained in detail using FIG. 4.

In Fig. 4, lO is a function generator that inputs the material length 4 of the rolled material and outputs the exit side plate thickness reference href, and the plate thickness reference href (Q) where 11 digits are correct, that is, 1 = OK.
12 is a conversion constant Ki, 13 is an integrator with an integral gain of 3, 14 is a hydraulic pressure reduction control device, 15 is a transfer function of a servo amplifier with a gain of 4, and 'rv is a time constant.

16 is the transfer function of the cylinder, and 16 represents 1/(cross-sectional area of the cylinder). 17 is a transfer function from the roll gap to the rolling load, M is a mill constant, and m is the plasticity coefficient of the rolled material. 18 is a block that calculates the elongation of the mill due to rolling load.

hg in the figure is the gauge meter plate thickness, and is calculated by the formula (1).

However, SO: gear setting value at no load ΔSO: gap change amount P: rolling load immediately after biting ΔP: rolling load change amount from P.

As is clear from equation (1), by accurately detecting the roll gap and rolling load and predicting the mill constant M, the exit plate thickness can be detected with high accuracy, which is possible with today's technology.

When changing the outlet side plate thickness into a tapered shape as shown in the function generator 10, the function generator IO outputs the outlet side plate thickness reference href(1) according to the longitudinal position of the rolled material.

The memory circuit 11 memorizes the plate thickness reference hre (0) at the tip of the rolled material, and stores the subsequent difference in the plate thickness reference l, that is, the output href (1) of the function generator in the outlet side plate thickness block 12. The plate thickness standard hre of the tip of the rolled material stored in the circuit 11
The difference Δhref(J) from t(o) is input.

The product of the conversion coefficient and 1 is output as a gearing reference for the hydraulic pressure reduction control device 14.

The change Δh in the outlet side plate thickness when the roll gap of the rolling mill changes ΔSo is expressed by equation (2).

Δh −−−Δ8o ・Curve (2) M 10 m Therefore, the amount of change in the roll gap required to give a change in plate thickness to the outlet side plate thickness is obtained from equation (2) and converted in Fig. 4. It is sufficient to set 1 as a constant as M+m K·=M−°(4).

But especially 41! During inter-rolling, there are changes in the temperature f in the longitudinal direction of the rolled material and changes in the thickness at the entrance side, so it is difficult to accurately determine the plasticity coefficient m of the rolled material in equation (4).

11, when the amount of plate thickness change is large, it is fully predicted that the plasticity coefficient m at each point of plate thickness change will change.

The present invention solves the above problem by adding a feedback loop using the gauge meter plate thickness hg as a feedback signal to this open-loop plate thickness changing method.

That is, the difference between the exit side plate thickness reference href (j) and the gauge meter plate thickness hg is input to the integrator 13, the output of the integrator 13 is added to the output of the block 12, and the hydraulic pressure reduction control device 1
Give to 4.

Since the difference between the integrator 13ii outlet side plate thickness reference href(1) and the gauge meter plate thickness hg is eliminated, the I outlet side plate thickness is accurately rolled to the target plate thickness in order to correct the roll gap.

As described above, the present invention makes it possible to roll a plate to a desired outlet thickness by changing the plate thickness standard of a plate thickness control device that is equipped with open-loop predictive control and feedback control using gauge meter plate thickness as a feedback signal. Features.

(61 Effect of invention An embodiment of the present invention shown in FIG. 5 will be described below.

The present invention provides a plate thickness reference generator A that outputs a target thickness of a steel plate on the exit side of a rolling mill corresponding to a position in the longitudinal direction of the rolled material in a plate thickness control device for a rolling bed that controls a steel plate or the like to a predetermined plate thickness. , a plate thickness standard change calculation device fB that calculates the change in the output of the plate thickness standard generator, detects the rolling load and roll gap of the rolling mill, and calculates the steel plate of the rolling mill using a gauge meter method from these various quantities. and a roll gap calculation device that calculates a rolling mill roll gap correction amount by integrating the difference between the output of the thickness calculation device C and the output of the thickness reference generator A. Equipped with rito. Each plate thickness reference generator A, plate thickness reference change amount calculation device B, plate thickness calculation device C, and roll gap calculation device are constructed and operated as follows.

The rolling roll l is driven by the electric motor 204C, and the electric motor 2
0 is set to a predetermined rotational speed by the speed control device 21. The roll gap between the pair of upper and lower rolling rolls 1 is set to a predetermined value by the hydraulic pressure reduction control device 14.

When the rolled material 2 is bitten by the rolling roll IK, the rolling load P is detected by the nine load detection 1!23 installed in the rolling mill, the roll gap 80 is detected by the rolling position detector 24, and the plate thickness calculating device 25 Enter.

The plate thickness calculating device 25 calculates the gauge meter plate thickness hg, that is, the actual plate thickness using a dirge meter type, and the calculated nine gauge meter plate thickness h1 is fed back to the plate thickness control device of the present invention. The signal is output to the subtracter 26 as a signal.

A speed detector 22 is attached to the electric motor 20, and the output of the speed detector 22 is sent to a function generator IO. The function generator 10 uses the output signal of the speed detector 22 to calculate the longitudinal position I from the tip of the rolled material 2, and determines the current rolled material position from a function of the preset rolled material position and the exit side plate thickness reference. Output plate thickness reference href(j) corresponding to the output side plate thickness is outputted to the subtractor 26.

The subtracter 26 calculates the difference between href(j) and hg and sends it to the integrator 13. The integrator 13 calculates the roll gap correction amount in order to make the plate thickness deviation calculated by the subtracter 26 zero, and the adder 2
Output to 7.

On the other hand, immediately after the rolled material 2 is bitten by the rolling roll l, the instantaneous gate 3G is closed, and the exit side plate thickness standard kr@f at the tip of the rolled material is
(0) is stored in the storage device 11. In other words, the tip plate thickness is taken as the initial value. The output of the function generator 10 is input to the subtracter 28 via a path 101, and the difference between it and the output of the storage device 11, that is, the amount of change in the outlet side plate thickness standard is calculated and sent to the multiplier 29.

In the multiplier 29, 1 is inputted to the conversion constant set in advance in the setter 21, and the product with the subtracter 28 is sent to the adder 27&C. The output of the adder 27 is inputted as a gap reference to the hydraulic pressure reduction control device ll14, and the roll gap of the rolling roll 1 is changed and controlled so that the exit side plate thickness is rolled to a desired plate thickness.

(g) 11 Combined Effects According to the rolling mill plate thickness control device of the present invention, products with good plate thickness accuracy can be rolled without increasing the production of the material, hardness, rolling schedule, lubrication, etc. of the rolled material. There are so many things to do.

Furthermore, the plate thickness control device of the present invention can have a simple circuit configuration since it is not necessary to accurately predict the illumination constant M and the illumination coefficient m expressed in equation (1). In order to detect and output the actual plate thickness, it is placed on the rolling mill. There is no detection delay and feedback control with quick response can be performed.

Therefore, even if an error occurs between the standard plate thickness and the actual plate thickness during rolling changes, the plate thickness control device operates quickly to correct the roll gap, allowing products with high plate thickness accuracy to be produced. It can be rolled, greatly improving production efficiency on production lines for high-mix, low-volume production.

In particular, the present invention is effective when rolling a sheet into a tapered shape.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a plate thickness pattern of a rolled material product, Figs. 2 and 3 are explanatory diagrams of the conventional method, Fig. 4 is a block diagram showing the functions of the present invention, and Fig. S is a diagram showing the function of the present invention. FIG. 2 is a block diagram showing one embodiment. 1... Rolling roll 2. ...Rolled material 1...
・・Down control device 4・・0. Subtractor S...Mu GC device 6,..., plate thickness needle 10...Function generation! ! 11. ,・Storage device 12...Conversion constant setter 13,...Integrator 14...Hydraulic reduction control device 15...Nervo amplifier block 16...Cylinder block 17...Gap change and rolling load change Transfer function 18 between...Transfer function 20 between rolling load and mill elongation
...Electric motor 21...Speed control device 22.
・・Fast detection detector 23・・・Load detector 24・・
・Reduction position detector 25・・・Plate thickness calculation device 26.2
8...Subtraction! 27. ...Adder 29...
・Multiplier 30 River Gate (7317)
Agent: Patent Attorney Kensuke Chika (IT or 1 person) 1st
figure? Figure 2

Claims (1)

[Claims] A plate thickness control device for a rolling mill that adjusts a steel plate, etc. to a predetermined plate thickness includes: a plate thickness reference generator that outputs a target thickness of the steel plate, etc. on the exit side of the rolling mill, corresponding to the longitudinal position of the rolled material; In order to calculate the amount of change in the output of the plate thickness reference generator, a plate thickness reference change amount calculation device is used, and the rolling load and roll gap of the rolling mill are detected, and based on these quantities, the steel plate of the rolling mill is determined by the gauge meter 2. A roll gap correction amount calculation unit that calculates a rolling mill Q-le gap correction amount by integrating the difference between the output of this plate thickness calculation device and the output of the plate thickness reference generator. and adding the output of the roll gap correction amount calculation device as a correction amount to the value obtained by converting the output of the sheet thickness standard change amount calculation device into a roll gap correction amount to produce an exit side plate such as a steel plate of one roll type A plate thickness control device for a rolling mill, which is characterized by rolling the plate thickness to a predetermined value.