JPS6188910A - Control method of sheet crown by adaptive control of work-roll bender - Google Patents

Abstract

PURPOSE:To improve the accuracy of crown control by obtaining a correction factor of rolling load, obtained from an estimated value of rolling load and a measured value thereof, etc. at the stand of front stage, as well as estimating the changing amount of crown of the next and subsequent stages, and correcting the setting of a roll-bender pressure. CONSTITUTION:When a sheet 10 is bitten by the (i)th stand, a load deviation is obtained from a measured rolling load PMi and a calculated rolling load PSi, to calculate a mill elongation. Next, a correction factor Ri of rolling load is obtained from the changing amount DELTAPPi of rolling load. Rolling loads P'i+1, P'i+2 corrected by multiplying the calculated rolling loads PSi+1, Pi+2 of the next stand 14 and the next but one stand by this factor Ri are obtained to correct the rolling reduction and the roll bender pressure. In this way, both of the accuracies of sheet thickness and crown control are improved.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a plate crown control method by adaptive control of a roll bender, and relates to a setting side 1ffl in plate crown control.
l This is an attempt to further improve the degree of accumulation.

[Conventional technology]

In multi-stage continuous rolling equipment, the rolling load of each rolling mill is distributed, the roll gap and the roll speed are set according to the rolling schedule, and the rolling load required for this setting calculation uses predicted values. However, the predicted value is not necessarily equal to the measured value, so we actually measure the rolling load when the slope is caught in the rolling mill, find the deviation from the predicted value, and use this deviation to adjust the rolling force of the subsequent rolling mill. Adaptive control is provided to modify the reduction and speed settings.

The deviation between the predicted value and the measured value of the rolling load can be determined at a specific stand or at each stand of the finishing rolling equipment. A load correction coefficient is obtained from this, and the predicted load is corrected based on this. PM the actual measured rolling load of the i-stand.
i, the predicted (calculated) rolling load is PSi, the slope of the plasticity curve used in the calculation is Qi, Fj is because this was actually Q'i, and the thickness change is ΔHi (in this method, the calculated value and The deviation in the measured value is considered to be due to the change in the slope of the plasticity curve), and as is clear from Figure 2 fa), Q'i/Qt
=PMi/(PS i+Qi・ΔHi) holds, so as Ri=Q'i/Qi, the load correction coefficient R
i is PSE+QiΔHi, and this coefficient Ri is the calculated rolling load PS of the rear stand.
The correction is made by multiplying j by the calculated load of the stand.

If the reduction screw is corrected by the operator or the like when the i-stand is engaged, the mill rigidity curve will become as shown by the dotted line in FIG. 2 fbl, and the operating point will move from B to B'. In this case, the plate thickness change ΔH1 is the sum of the change in the plasticity curve and the change in the roll gap (change in the mill stiffness curve), and the change in rolling load ΔPi=PSi−P
Using Mi, mill rigidity Mi, and roll gear/7 gear change amount ΔS1□=SS IS M l, ΔHi=ΔS
11+ΔS, 2, but can be expressed as Δ5I0−ΔPi/M.

In addition, the plate thickness change ΔHi that occurred in the l stand becomes the entry side plate thickness error of the next 1+1 stand, and in this case, the plasticity curve is the second
It moves in parallel as shown by the dotted line in Figure (C). ΔL (is the change in plate thickness on the entry side, ΔSi is the change in the plasticity curve (change in plate thickness on the entry side)
This is the change in plate thickness on the exit side due to the rolling load change ΔPi
There is a relationship of ΔP=M·ΔS for =PSi−PMi.

Also, ΔS is ΔS (M+Q
)=QΔH, so the rolling load change ΔP is ΔP=
MQΔH/(M-1-Q). Considering this ΔP, the corrected rolling load PSj of the next stand (referred to as "i+1 stand") is Fig. 3, which is an explanatory diagram of the multi-stage continuous rolling equipment subjected to the above control, and 10 is a steel plate which is the material to be rolled. , 12, 14. 16.・・・
... is the i-th, i-th+1. i+2... Each rolling stand, 1 day is a computer (process computer) that performs rolling settings, etc. for these rolling stands.

The corrected screw value Si+I + Si+2 of the i+l stand and i+2 stand is the corrected rolling load P++I,
Pi+2 Screw value before correction Ss1+ l+ Ss,
It is calculated by the following formula using +2.

M1+2 By performing such adaptive control, the plate thickness control: I'i' can be further improved. In addition, when considering the change in the thickness of the entrance side plate, it is necessary to make the correction in equation (3), but this correction is only necessary for the next stage 14 after the measurement stage 12, so here, (
3) Correction using formula is omitted.

[Problem that the invention seeks to solve]

The difference between the calculated value and the measured value of the rolling load is due to the temperature of the rolled material11
11 constant and component changes (approximately speaking, due to changes in the gradient of the linearized plasticity curve), the calculated rolling load is corrected through adaptive control. Specifically, the 1:1-rule setting gap is adjusted. If you modify it, the plate shape, especially the plate crown, will change. The present invention aims to suppress crown prediction errors caused by such load prediction errors and fluctuations in the plate crown due to this adaptive plate thickness control, thereby keeping the plate crown setting control accuracy within a desired range.

[Means for solving problems]

In a multi-stage continuous rolling facility where plate thickness control and crown setting control are performed simultaneously, the present invention is based on the predicted value PSi and actual measurement value PMi of the rolling load of the front stage L stand, and the rolling load change ΔPPi due to the change in plate thickness. 1. Correcting the roll gaps of the stands after the next stage 1+1 stand using the calculation means for calculating the positive constant Ri and the cough rolling load correction coefficient Ri. Using the correction coefficient Ri and the corrected roll gap S i+ I, the next stage i −j
- It has a dynamic setting function that includes a correction means that predicts the crown changes after the 1st stand and changes the set value of the roll hender pressure of the stand before the (i + 1) stand engages so that the changes become zero. It is characterized by:

Crown C is rolling load P10 - pending force F10
It is related to the roll profile Co, and the control model equation is expressed as follows.

C=f (P, F, Cf, Co) When automatically controlling the crown using this crown control model, a predicted load (the above-mentioned calculated load) based on finish setting calculation has conventionally been used. In order to improve crown setting control accuracy, the present invention predicts crown deviation from the error between the measured rolling load and the predicted rolling load of the front stand, and furthermore, non-interference of crown changes through adaptive plate thickness control. Modify the setting value of the work roll bender force of the rear stage stand so that this becomes 0.

To explain this with reference to FIG. 1, the same parts in this figure as in FIG.
, 14 and 16 are the i-th, i-th ``1 + i-th + 2 rolling stands.This multi-stage continuous rolling equipment is a finishing stage, and although only 3 stages are shown in the figure, generally there are 6 stages, 7 stages, etc. Consists of 12 i-stands (first-stage stands here)
When the plate 10 is bitten, calculate the load deviation ΔPi=PMi−PSi between the measured rolling load PMi and the calculated rolling load PSi, and divide this load deviation by the mill constant M to obtain the mill elongation Δ
Find 5il-ΔPi/MMi. Also, the aforementioned Ss and s
Screw deviation Δ5t2=Ss1-3M1 from MO difference
is calculated, and the rolling load change amount ΔPPi is calculated using the following formula.

ΔPP1=Qix(ΔSil+ΔS, 2)...
(6) Actual measurement of rolling load and rolling reduction and the above ΔPi,
ΔS11°ΔS12. Calculation of ΔPPi is performed for each stand after the next stand, and the rolling load correction coefficient R1 is determined using the following formula.

Once the rolling load correction coefficient Ri is determined, this is multiplied by the calculated rolling loads P S1++ and P S++2 to correct the next stage i+l stand 14 and the next 1+2 stand 16. Corrected calculated rolling load P,, ++ = R1 -PS1+
1+P,+2=R1-PS; +2 is determined and the reduction is corrected as described above, but in the present invention, in addition to this, the roll hender pressure is corrected.

If the appropriate correction is made, the calculated rolling load will have a deviation ΔP.
i+l =P, +I P Si+1・ΔPi+2=
Pi+2・P S , +2 occurs, and this deviation causes a change in the plate crown, and crown variation ΔC* due to adaptive plate thickness control also occurs.In order to make the sum of these O, change the bender force and move in the opposite direction. It is sufficient to cause a change in the plate crown. That is, the Bengu force correction value ΔFi+l+ΔF1+2 is generated, and the work rolls of the i+l stand and i+2 stand are generated. Ko\T: (81 formula (7) (aC/ap)
1+ t , (aC/ap), + 2 is i+l, i+
Crown change due to change in seeding and rolling load of two stands, (
aC/aF), +1. (aCroE), 2 is i+l
, shows the crown change with respect to the change in the roll bending force of the i+2 stand, and F1+1F1+2 in equation (7) shows the calculated roll bending force of each stand i+l and i+2, and Δc*i+ 1 + ΔC*1+ 2 represents the change in the roll bending force of the i+1゜i+2 each. This is the amount of crown change due to adaptive plate thickness control of the stand.

〔Effect of the invention〕

As explained above, in the present invention, the rolling load correction coefficient Ri is determined from the predicted value Psi and the measured value of the rolling load of the first stage stand, PMi, and the rolling load change ΔPPi due to the change in plate thickness, and this is used to calculate the rolling load correction coefficient Ri of the rolling load of the next stage stand. In addition to correcting the subsequent rolling reduction of the rolling mill, the amount of crown change is predicted and the roll hender pressure setting is corrected so that this value becomes O, so it is possible to accurately control the plate thickness and slope cradle, which is extremely effective. .

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the present invention, FIG. 2 is an explanatory diagram of the operation, and FIG. 3 is an explanatory diagram of adaptive plate thickness control. In the drawing, 10 is a rolled steel plate, 12.14. . . . is each stand of the multi-stage continuous rolling equipment.

Claims (1)

[Claims] In a control method for a multi-stage continuous rolling facility in which plate thickness control and crown control are performed at the same time, a predicted value PSi of the rolling load of a previous stage i-stand, an actual value PMi when the i-stand is bitten, and a change in plate thickness. Calculate the rolling load correction coefficient Ri from the rolling load change ΔPP due to the rolling load correction coefficient Ri, use the rolling load correction coefficient Ri to correct the roll gap of the stands after the next stage i+1 stand, and use the correction coefficient Ri to correct the roll gap of the next stage i+1 stand The subsequent crown change is predicted, and the crown change based on the adaptive plate thickness control is predicted, and the sum of these changes is set to zero (i+1
) A plate crown control method using work roll bender adaptive control, characterized by changing the set value of the roll bender pressure of stands after the (i+1) stand before the stand bites.