JPS60247408A - Method for controlling sheet thickness during passing through continuous hot rolling mill - Google Patents

Abstract

PURPOSE:To execute surely screw-down correction with fast response by detecting the deviation of rolling load and the deviation of screw-down position at the point of the time when the corresponding stand bites the front end of a material to be rolled, determining the screw-down correction rate of the succeeding stage according to the detected deviations and correcting the screw-down before the stand bites the front end. CONSTITUTION:The deviation DELTAPi of the rolling load and the deviation DELTASi of the screw-down position indicating the deviation from a preliminarily given target value are detected by the load cell 14i of the corresponding i-th stand and a screw-down position detector provided to a screw-down position control device 16i right after the rolls 12i of the corresponding i-th stand bites the front end 10A of the material 10 to be rolled. The prescribed calculation is made in a computer 20, etc. by the detected values thereof and the rolling reduction DELTASi+1* of the succeeding (i+1)-th stand is calculated. The screw-down position of the roll 12i+1 is changed by the screw-down position control device 16i+1 of the (i+1)-th stand before said stand bites the front end. As a result the safe control is executed even if there is a detection error in the rolling load and the screw-down position. The titled control of the sheet thickness by which the target sheet thickness is surely obtd. from the front end of the coil is thus executed.

Description

[Detailed description of the invention]

[Field of Application of Soil Collection] The present invention relates to a method for controlling plate thickness during sheet passing in a hot continuous rolling mill, and in particular, a hot continuous rolling mill suitable for application to a hot @ continuous finishing rolling mill. This invention relates to an improvement in a method for controlling plate thickness when passing a rolled material through the plate. [Conventional technology 1] In order to obtain a good thickness from the tip of the coil during sheet passing in a hot continuous rolling mill, such as a hot continuous finishing rolling mill, the rolling position of each stand must be set to an appropriate value in advance. (setup) is necessary. Traditionally, the rolling reduction setting for each stand was done by analogy with past rolling data, operator experience, etc., but recently rolling theory formulas (rolling load formula, deformation resistance formula, rolled material humidity formula, etc.) have been used. Increasingly, this is done using computers. However, even if the reduction settings for each stand are determined by theoretical calculations, it is difficult to see that they are actually the optimum values, and it is not always possible to obtain a good plate thickness from the tip of the coil. This is due to the fact that there is a problem with the accuracy of the theoretical formula used for setup planning, and the rolled material at the entrance of the finish rolling mill, which is detected by a radiation thermometer, etc., which is necessary as an input condition for calculation. This is because there is a detection error in the temperature of the plate or the plate thickness calculated by the gauge meter formula, etc. Among these, the former theoretical formula can be improved by accumulating rolling performance data, but the arrogant Currently, it is difficult to measure the temperature and thickness of the rolled material at the entrance of the finish rolling mill with high accuracy.In particular, temperature measurement is difficult due to problems such as the surface properties of the rolled material or water riding. Not only are there many discrepancies between measured values and actual values;
What is required for set-up calculations is the average temperature in the plate thickness direction, and there is no other way to estimate this other than from the measured surface temperature. From the above points, in order to obtain a good plate thickness from the tip of the coil, it is necessary to correct the lowering position of each stand to an appropriate value during threading. As a countermeasure for this, a gauge meter AGC (ΔautomaLic G
It is conceivable to adopt the control from the time of sheet threading, but since the feedback is 1110,
The responsiveness of the rolling down device becomes a problem, and it is difficult to obtain a good thickness from the tip of the roll. In addition, as another method, the rolling load It of the front stand
Detect the difference, calculate the deformation resistance deviation from this, and assume that the deformation resistance deviation is the same in the subsequent stand.
A method (Japanese Patent Publication No. 51-2061) has been proposed for correcting the lowering position of the rear stage stand within a short time. However, the deformation resistance is a complex function of the temperature of the rolled material, reduction rate, and chemical composition, and it is difficult to predict the deformation resistance of the rear stand from the deformation resistance of the front stand. On the other hand, the inventors 1. As a solution to the problem described in E, it has already been proposed in Japanese Patent Application No. 58-156044 that the tip of the material to be rolled gets caught in the first stand from the first stream when it is passed through a continuous rolling mill. At this point, the rolling load deviation and rolling position deviation of the first stand are detected, and the rolling load f
The next stage ++1 is determined based on the detected values of f1l difference and rolling position deviation.
The temperature deviation and entry side plate thickness deviation of the rolled material at the stand are predicted, and the first
The amount of correction of the rolling position of the +1 stand is calculated, and before the tip of the material to be rolled is bitten by the i+1 stand, the
It is characterized by correcting the rolling position of one stand.
This paper proposes a method for controlling plate thickness during rolling in a continuous rolling mill. This method quickly corrects the rolling position of the i+1st stand using only the rolling load deviation and the rolling position "Ill deviation" when the tip of the material to be rolled is bitten by the first stand. This is a very effective control method when there is no detection error in the rolling load or rolling position, and the response is quick.
This method has the advantage that the reduction can be reliably corrected, and therefore the target thickness can be obtained from the tip of the coil. However, if there is a detection error in the rolling load or the rolling position, there is a problem in that the control becomes unstable. 1 Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned conventional problems, and has a quick response and can reliably perform reduction correction.
Moreover, even if there is a difference in detected WA in rolling load or rolling position, the continuous hot rolling mill can perform stable control and reliably obtain the target thickness from the tip of the coil.

[The purpose is to provide a method for controlling sheet thickness during sheet threading. rMeans for solving problems]

In the present invention, when passing a material to be rolled through a continuous hot rolling mill, as shown in FIG. At this point, the rolling load deviation and rolling position deviation of the first stand are detected, and the temperature deviation and outlet side plate thickness deviation of the rolled material at the first stand are calculated from the detection chamber of the rolling load deviation and rolling position deviation. , Calculate the temperature deviation and exit side plate thickness deviation. From this calculation, predict the humidity deviation and entry side plate thickness deviation of the rolled material at the 11th stand of the next stage, and calculate the temperature deviation and the entry side plate thickness deviation from the predicted values. The rolling position deviation of the 1+1 stand is calculated, and when the tip of the material to be rolled is caught in the 1+1 stand,
The above object is achieved by setting the lowering position of the i+1th stand to 11. [Effect 1] The present invention has been made with the focus on the fact that the main cause of plate thickness variation in continuous hot finish rolling is temperature variation, and that this temperature variation can be recognized as rolling load variation. In the present invention, as shown in FIG.
Immediately after the tip 10A of the first stand is bitten by the roll 12i of the first stand, the rolling load deviation ΔPi, which represents the deviation from the predetermined target value, is also changed to the rolling position @ difference 81,
The pressure is detected by the load cell 14+ of the first stand and the pressure-down position detector (not shown) provided in the pressure-down position control device 161, and predetermined calculations are performed at the total I'1l1120, etc., and the pressure of the next stage 1+1 stand is detected. Correction-
ΔS, 4Ix, and before the tip of the i+1st stand is bitten into the 1st+1st stand, the lowering position control device 16 i
+1 changes the rolling position of the roll 12 i-+. In the figure, 22 is a louver. 4 Physically, the tip 10A of the pressurized li1 shrine 10 is the first
Temperature deviation of the rolled material immediately after it is bitten by the stand Δ−“1
'- is measured by the following formula from the detected value of H' lower position I difference Δs+ and rolling load deviation ΔP1. △l'I'= L△P i -f (aP/aH)
i×Δ1li−+ ′ + (a P 2” a S
) ixΔS i, ) 3 / (aP7"aT')
i - (1) where the subscript i is the stand number, iP,
'aH>, (,3P/as), (a P , /a T
) i, t, influence of entrance plate thickness H1 on smooth rolling load P
The shadow coefficient of the rolling position S and the temperature T of the rolled material, Δh'f, is the difference in gauge meter plate thickness IIjA. To set the pressure, Masaaki ΔS,...
N, l' and the entrance board J! Predict the pot difference ΔH + 41″F (there is a number of cores. Among these, the temperature difference Δi
'i! IP can be predicted only from the humidity S difference ΔT, 6 of the first stand, but it can be predicted from the earlier
Temperature difference @difference between the 1st stand and the i-1st stand that has already been calculated when the tip is bitten by the 1st stand △r1°
~ΔT +−1′ can also be predicted. That is, the temperature of the 1st +1st stand (II; fJΔI” 1i
vl 1' can be predicted by the following equation. Δ−ri◆1P=α1・rvj・ΔT+'+α2・rT
2・Δ1−26 10...+α1・fTi・ΔTi(−...(2) rv
+=T+° l・・1゜r T 2 = T 2 '/'-1'+41' ・
...(3)f Ti=T+"/''r' + or 1° Here, King 7 is the temperature of the rolled material in the standard 1-mole rolling schedule, and α is α1+α2+...10αi=1 The brightness that satisfies the relationship is a constant.For example, if there is no error in detecting the rolling load deviation △P1 and the rolling position difference △S1, the temperature deviation △T+ of the first stand
' It is better to use only the temperature of the i+1st stand (liil
It is considered that the prediction N degree of the difference ΔTi1l' is high, and in this case, α1=α2=...=α+-+=O1αi=1
(Japanese Patent Application No. 58-156044). However, if there is a large possibility of a detection error in the rolling load deviation ΔP1 and the rolling position deviation ΔS1, all of the temperatures fMlp@ΔT+' to ΔT− of the first stand to the first stand are used to calculate the temperature deviation of the ΔTi. Pulling 11' is more stable as a control (1). That is, the temperature deviation of the 1st + 1st stand is 6 +. When predicting IF, which of the temperature differences ΔT1 to T+ from @1 stand to 1st stand should be used depends on the operating conditions of the target continuous hot rolling mill (especially rolling load deviation ΔPi and rolling position deviation It should be determined by the detection accuracy of ΔS1). On the other hand, the entrance board J of the i+1st stand? The deviation ΔHbl' is the gauge meter exit plate thickness deviation ΔbicT of the first stand.
Since it is equal to , it can be determined by the following formula. Δt-b++'=Δh, t=ΔS1+ΔPl/Mi...<4) Here, M is Mill's constant. The exit plate thickness aXΔh 1 and IP at the 1+1 stand predicted from the humidity deviation ΔT1.1 of the 1+1 stand and the entry plate thickness deviation ΔFlb+' predicted in this way
is calculated using the following formula. Δ h i41' = < (a P 7"a T )
t −Δ T+−+′+ (a P 4a H)!
・ΔHb+Pl/Mt-+... (5) Therefore, the exit plate thickness deviation of the 1st+1st stand Δh i41
The compression ratio ΔS ill x to reduce ' to zero is determined by the following equation. Δ S is '--[(Mb+ -(2)P/ah
',) + and 1)/M+. 11×Δhkl? '...
-(6) Here, (aP, /ah> is the influence coefficient of the tapped plate thickness on the rolling load P.
When the first stand is caught in the first stand, the rolling load deviation ΔP+ and rolling position deviation ΔS1 are detected, and the next stage 1+1
Temperature deviation of rolled material in stand Δ'rt++T'f, ti
ll (1) ~ (3) formula, J: S, m plate thickness deviation △Hk
Predict lP from equation 4) above, then use equation (5) above, (
6) Using the formula, calculate the reduction correction unit ΔS of the 1st + 1st stand.
Ill x, the lowering of the i+1st stand is corrected before the tip 10A is bitten by the i+1st stand.

【Example】

In the 7-stand continuous hot rolling mill, the above (2)
The weighting in the formula is constant α1=α2=...=σi=
1 / I When the present invention is implemented (referred to as the CI Shimokimoto method), the plate thickness accuracy (standard deviation of the final exit plate thickness deviation) at the tip of the coil is compared to the conventional method with no 11 Jl and α1 =
... = αr-+ = O1 αi = 1.0 The results of comparing the plate thickness accuracy at the tip of the coil with the method proposed in Japanese Patent Application No. 156044 (hereinafter referred to as the comparative method), where
Shown in the table. As is clear from Table 1, the present invention is particularly effective for thin materials, compared not only with the conventional method but also with comparative methods, and the thickness defect at the tip of the coil is greatly improved, resulting in improved yield. Really good rolling of 11! Doing so becomes Shun Noh.

【Effect of the invention】

As explained above, according to the present invention, the response is quick, the reduction can be reliably corrected, and the rolling correction is fast. 1tjl
Stable control can be performed even if there is a detection error in the low-level or sweat-related combat. Therefore, the excellent effect of being able to reliably obtain the target thickness from the tip of the coil is achieved.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the gist of the method for controlling one sheet during sheet passing in a hot rapid continuous rolling mill according to the present invention, and Fig. 2 is a flowchart showing the outline of a method for controlling a sheet during rolling in a hot rapid continuous rolling mill according to the present invention. FIG. 2 is a block diagram showing the configuration of a plate thickness control I-ring of a finishing rolling mill. 10... Rolled material, 10A... Tip, 14i...
- Load cell, △P1... Rolling load deviation, 16i... Rolling lower-control device, ΔS1... Rolling load deviation, 20... Calculator, Δ314. *・・・Reduction correction amount, ΔT+'...Temperature deviation of rolled material (calculated value), ΔhΦ・
・Gauge meter outlet side plate thickness fFl difference (calculated value), ΔT
ill F...Temperature deviation of rolled material (predicted value), ΔH1
, I'... entry side plate thickness deviation (predicted lI). Agent Takaya Ron (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] (1) Pressurized by hot continuous rolling mill! When pulling fI overboard, when the tip of the material to be rolled is caught in the first stand from upstream, the current DI'! + Rolling load of stand [i deviation r
e and the rolling position width difference are detected, and the rolling? Iji heavy Ill
From the detected values of the difference and the width difference of the rolling position, the difference in rolling I￥m of the material to be rolled at the first stand and the exit side plate thickness I5! Calculate the concentration deviation and the calculated value of the exit plate IIF difference to the next stage @1
Pressure iI with +1 stand! Kaizaki deviation and entrance board J of the shrine
9'l￥F was predicted, and from the predicted values of the temperature Iv difference and the entry side plate thickness difference, the rolling depth of the 1st + 1st stand was determined to be -, and the tip of the rolled material (the tip of A was placed on the 1st + 1st stand). 1% +1 to be bitten, 1st +
A method for controlling sheet thickness during sheet passing in a continuous hot rolling mill, which involves correcting the rolling position of one stand.