JP2008043967A - Method for controlling shape of plate in hot rolling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately controlling the shape of a plate in hot rolling in tandem type hot rolling facilities having a few measuring means by enabling an accurate prediction of flatness by appropriately determining a shape change coefficient of a prediction model for the crown and flatness of the plate from data to be usually measured. <P>SOLUTION: The method for controlling the shape of the plate in hot rolling comprises a step for calculating a plate crown prediction value of a rolled plate by a plate crown prediction model, and a step for calculating the determined value of a flatness prediction value using a shape change coefficient determined so as to increase the absolute value of a correlation coefficient between an operator's adjustment value manually adjusted by an operator for operating a tandem type rolling mill and the flatness prediction value calculated by a flatness prediction model. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for controlling a plate shape of a rolled material that is hot-rolled by a tandem rolling mill having a plurality of rolling stands arranged in series. More specifically, the tip of the plate is passed through the tandem rolling mill. Setting calculation of roll bending device, roll shift device, and cross angle setting device of pair cross mill for controlling plate crown (plate thickness difference in plate width direction) and flatness of plate to target values when plate The present invention relates to a plate shape control method for predicting a plate shape and controlling the plate shape based on the predicted value.

  In tandem rolling mills used in hot rolling, not only does the sheet crown fall within the product specifications, but also because the flatness of the sheet is disturbed during the sheeting operation of rolling steel through the tandem rolling mill. In order to avoid plate trouble and to achieve uniform cooling in the cooling zone after rolling, it is necessary to appropriately control the flatness of the plate. For this reason, before rolling the rolled material, the rolling material at each stand is determined from the dimensions of the material, the target plate thickness (pass schedule) on the exit side of each stand, the target value of the plate crown, and the flatness tolerance. After performing the calculation of the temperature and rolling load, the prediction of the plate shape represented by the plate crown and flatness at each stand is performed, the plate crown after hot rolling becomes a value within the target range, and The set values of the shape control devices such as the roll bending device, the roll shift device, and the cross angle setting device of the pair cross mill are determined so that the flatness is within the allowable range. In calculating the set values of such a tandem rolling mill, the accuracy of predicting the plate crown and flatness at each stand is extremely important. In other words, if the plate shape is mispredicted, the flatness will be disturbed during threading, which will not allow the material to smoothly enter between work rolls, and may cause problems such as poor penetration and throttling. become.

  Conventionally, as a method of improving the prediction accuracy of the plate crown and flatness used for setting value calculation of a tandem rolling mill, the plate crown and flatness are actually measured on the exit side of the final stand, and the prediction calculation of the plate crown and flatness is performed. Assuming that the difference from the value is caused by the estimation error of the roll profile, a method of estimating the prediction error of the roll profile of each stand and correcting the plate crown and flatness at the next setting to the target values is known ( For example, see Patent Documents 1 and 2). In the method of estimating the prediction error of the roll profile from the plate crown and flatness measured at the final stand exit side described in Patent Document 1 and Patent Document 2, when each measuring stand is not provided, It is necessary to estimate the prediction error of each stand by making some assumption on the prediction error of the stand. In the plate crown / shape control methods described in Patent Document 1 and Patent Document 2, all roll profile prediction errors in each stand are all estimated. A method is disclosed in which the same stand is used, or the stand is determined so as to be proportional to the plate thickness on the exit side of each stand.

  In addition, a method of controlling the plate shape by changing the flatness evaluation point according to the rolling condition is also known (see, for example, Patent Document 3). The method of changing the flatness evaluation point according to the rolling conditions described in Patent Document 3 changes the position of the flatness evaluation point x, which is the distance x from the plate end in the plate width direction, according to the plate thickness. Then, the mechanical crown (uniform load crown) of the plate end (evaluation point x) is obtained, and the shape of the plate is controlled based on the plate crown and flatness calculated from the mechanical crown and the like of the plate end.

Japanese Patent No. 3253013 JP-A-7-303911 JP-A-7-227610

  However, in the method of estimating the roll profile prediction error from the plate crown and flatness measured on the final stand exit side described in Patent Document 1 and Patent Document 2, the roll profile is the thermal expansion of the roll or the roll. Since it is determined by the wear, etc., and the thermal expansion and wear of the roll depend on the rolling conditions and the type of roll used, there are rolls with high thermal expansion and low wear, and conversely rolls with low thermal expansion and high wear. There is also. Further, there may be a case where the prediction accuracy of thermal expansion is good but the prediction accuracy of wear is bad, or vice versa, or the prediction accuracy of thermal expansion and the prediction accuracy of wear are both bad. For this reason, the profile prediction error of each roll is inherently independent, and the roll profile prediction error at each stand is the same for all stands, or is proportional to the plate thickness at the exit side of each stand. Furthermore, the profile prediction error does not always have a correlation between individual rolls. Therefore, it is not always possible to correctly estimate the roll profile prediction error of each stand from only the measured values of the plate crown and flatness of the final stand.

  On the other hand, in the method of setting the flatness evaluation point for each plate thickness described in Patent Document 3, it is assumed that the plate crown on the stand exit side is correctly calculated. If there is no measurement means, an appropriate plate crown cannot be easily obtained.

  From the above, for example, in the conventional method as described above, depending on whether the prediction error of the roll profile at each stand is caused by the prediction error of thermal expansion or the prediction error of roll wear, In order to overestimate or underestimate the prediction error, there are limits to improving the accuracy of flatness calculation in various rolling conditions and in rolling mills that use both high-speed rolls and normal rolls with low wear. There is. Moreover, in a normal rolling mill, the rolling load of each stand and the setting performance of the control actuator can be easily collected, but in most cases there is no measuring means for the plate crown and flatness between each stand. The rolling mill which can apply the method which presupposes the measurement result of the sheet | seat crown between flats and flatness is very limited.

  The present invention has been made in view of the above circumstances, and its purpose is to change the shape of the prediction model of the sheet crown and the flatness from the normally measured data in a tandem hot rolling facility with few measuring means. It is an object of the present invention to provide a plate shape control method with high accuracy in hot rolling by appropriately determining a coefficient and realizing highly accurate flatness prediction.

Means and effects for solving the problems

  The plate shape control method in hot rolling according to the present invention relates to a plate shape control method for a rolled material that is hot-rolled by a tandem rolling mill having a plurality of rolling stands arranged in series. And the plate shape control method in the hot rolling according to the present invention has the following features in order to achieve the above object. That is, the plate shape control method in the hot rolling of the present invention includes the following features alone or in combination as appropriate.

The first feature of the control method of plate-shaped in the hot rolling according to the present invention for achieving the above _{object, Cr i = α × Cr Mi} + (1-r i) × β × Cr i-1 (Cr _i , Cri _-1 : plate crown on the exit side of i, i-1 stand, α: transfer rate, Cr _Mi : mechanical crown of i stand, r _i : reduction rate of i stand, β: genetic coefficient) The tandem rolling mill is operated with a set value of a plate crown prediction value calculating step for calculating a plate crown prediction value of the rolled material by a plate crown prediction model and a plate shape control device for controlling the plate shape. Using the shape change coefficient determined so that the absolute value of the correlation coefficient between the operator adjustment amount when the operator manually adjusts and the flatness prediction value calculated by the flatness prediction model is large, the flatness Degree prediction model Control device setting for calculating a set value of the plate shape control device using a flatness predicted value calculation step of calculating a determined value of the flatness predicted value by the level, the predicted plate crown value, and the determined value And a value calculation step.

  According to this configuration, the shape change coefficient of the flatness prediction model can be corrected based on the operator adjustment amount intervened by the operator operating the tandem rolling mill to improve the flatness of the rolled material, and adjustment based on actual experience is possible. The result can be reflected in the flatness prediction calculation of the plate. Here, since the operator adjustment amount is left to the judgment of the operator who actually operates, the accuracy of the visual judgment by the operator is a problem, but in the case of an experienced operator who has experience, the plate shape is accurately determined by visual inspection. It is possible to determine and adjust, and to correct to a plate with good flatness while avoiding troubles of plate passing. Further, since the data of the operator adjustment amount is accumulated every time the rolling is repeated, the accuracy of the shape change coefficient increases as the rolling is repeated.

  Further, in the present invention, since the flatness is predicted and calculated using the operator adjustment amount between stands that are easy to collect without using the measurement result of the plate crown or flatness, the plate crown or flatness between the stands is calculated. Even if the measuring means is not provided, the flatness between the stands can be predicted without assuming the roll profile prediction error. Therefore, in a tandem hot rolling facility with few measuring means, it is possible to appropriately determine the shape change coefficient of the prediction model of the plate crown and flatness from normally measured data, and to predict the flatness with high accuracy for each stand outlet. Therefore, it is possible to control the plate shape with high accuracy in hot rolling for each stand.

The second feature of the control method of plate-shaped in the hot rolling according to the present invention, the flatness prediction _{model, Δε i = ξ × (Cr} i / H i -Cr i-1 / H i-1 ) (Δε _i : Flatness on the exit side of the i stand, Cr _i , Cri _-1 : Plate crown on the exit side of the i, i-1 stand, H _i , H _i-1 : On the exit side of the i, i-1 stand (Plate thickness, ξ: shape change coefficient).

Here, Cr i _/ H _i is the ratio of the i stand delivery side of the strip crown and i stand delivery side of the plate thickness, generally is referred to as i stand delivery side of the strip crown ratio. According to this configuration, the flatness prediction value calculated from the conventional flatness prediction model defined by multiplying the change amount of the plate crown ratio before and after the i-stand by the shape change coefficient, and the operator operating the tandem rolling mill The shape change coefficient is determined from the correlation with the operator adjustment amount intervened by the operator, and the determined value of the flatness prediction value is calculated using this shape change coefficient, so that the operator adjustment amount is reflected in the flatness prediction value. It is possible to simply obtain a flatness prediction value with higher accuracy than the flatness prediction value calculated from the conventional flatness prediction model.

The third feature of the method for controlling the plate shape in hot rolling according to the present invention is that the flatness prediction model is Δε = ξ × (Cr ⁿ / H ⁿ −Cr ⁿ⁻¹ / H ⁿ⁻¹ ). ([Delta] [epsilon]: flatness stand outlet ^{side, Cr n, Cr n-1} : n, n-1 -th plate stand delivery side of the strip crown during the ^{rolling, H n, H n-1} : n, n-1 It is expressed by the thickness of the stand exit side during the rolling of the main plate, ξ: shape change coefficient.

Here, the plate crown, as described _{above, Cr i = α × Cr Mi} + (1-r i) × β × Cr i-1 (Cr i, Cr i-1: i, i-1 stand delivery side Plate crown, α: transfer rate, Cr _Mi : mechanical stand of i stand, r _i : rolling reduction of i stand, β: genetic coefficient), for example, for each stand If there is a difference in the prediction accuracy of the mechanical crown Cr _M , errors are gradually accumulated in the predicted value of the plate crown in the order of i stand and i + 1 stand. In addition, there may be a large difference in the prediction accuracy of the roll profile for each stand. Therefore, according to this configuration, the flatness prediction for predicting the flatness by the difference between the plate crown ratio of the rolled material rolled to the (n-1) th roll of the same stand and the plate crown ratio of the rolled material rolled to the nth roll. By defining the model, the prediction error of the mechanical crown and roll profile can be canceled out. Therefore, it is possible to realize more accurate flatness prediction.

The fourth feature of the control method of plate-shaped in the hot rolling according to the present invention, the flatness prediction ^{_{model, Δε i = ξ × {(}} Cr i n / H i n -Cr i n-1 / _{^{H i n-1) - (}} Cr i-1 n / H i-1 n -Cr i-1 n-1 / H i-1 n-1)} (Δε i: i stand delivery side flatness, Cr _{^{i n, Cr i n-1}} , Cr i-1 n, Cr i-1 n-1: n, i during the rolling of the n-1 -th plate, i-1 stand delivery side of the strip _{crown, H} ^{i n} , H _i ^n-1 , H _i-1 ⁿ , H _i-1 ^n-1 : thickness of the i, i-1 stand exit side during rolling of the n, n-1th plate, ξ: shape change coefficient ).

  Here, this flatness prediction model is based on the amount of change before and after the i stand of the difference between the plate crown ratio of the rolled material rolled to the (n-1) th sheet and the sheet crown ratio of the rolled material rolled to the nth sheet. A flatness prediction model for predicting flatness is defined. According to this configuration, the definition from the amount of change in the sheet crown ratio before and after the conventional i stand, the sheet crown ratio of the rolled material rolled to the (n-1) th sheet, and the sheet crown ratio of the rolled sheet rolled to the nth sheet. By combining the definition based on the difference with the above, it is possible to predict the flatness with higher accuracy.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a hot rolling facility provided with a tandem rolling mill in which the plate shape control method in hot rolling according to the present invention is used.

  As shown in FIG. 1, a steel slab 5 called a slab heated to 1000 ° C. or higher in a heating furnace 11 is first supplied to a roughing mill 12 and roughly rolled. After that, it is supplied to a tandem rolling mill 13 which is a finishing rolling mill, and finally thinned to a thickness of about 1.2 mm to 19 mm and cooled by a cooling facility 14 and then coiled by a winder 15. It is wound up.

  FIG. 2 is a flowchart showing a procedure for calculating various set values of a tandem rolling mill in which the plate shape control method in hot rolling according to the present invention is used. In the method for controlling the plate shape in the hot rolling according to the present invention, the set value of the shape control device of each stand is calculated according to the procedure of the flowchart shown in FIG. 2 and the tandem rolling mill 13 is set up.

  First, the material dimensions of the plate as a rolled material, the temperature of the plate at the entry side of the tandem rolling mill 13, the target temperature of the plate at the final stand exit, and the target plate thickness (pass schedule) at each stand exit , Step 1 (hereinafter referred to as S1, the same applies to other steps), the plate crown on the entry side of the tandem rolling mill 13, the target plate crown of the rolled plate, and the flatness tolerance of the plate Step 2 is entered. Next, based on S1, Step 3 for calculating the temperature of the rolled material at each stand and Step 4 for calculating the rolling load at each stand are performed. Thereafter, in step 6, set values of the roll gap and rolling speed of each stand are calculated. On the other hand, the predicted values of the flatness of the crown and the plate on the stand exit side are obtained in step 5 including the plate crown predicted value calculating step and the flatness predicted value calculating step based on the calculation results of S3 and S4 based on S1 and S2. Is required. Thereafter, in step 7, which is a control device set value calculation step, based on the result of S5, a set value calculation of a plate shape control device of each stand such as a roll bending device, a roll shift device, and a cross angle setting device of a pair cross mill Is done.

  In such setting value calculation of the tandem rolling mill 13, the accuracy of predicting the plate crown and flatness of each stand is extremely important. In other words, if the plate shape is mispredicted, the flatness will be disturbed during threading, which will not allow the material to smoothly enter between work rolls, and may cause problems such as poor penetration and throttling. become.

Here, the calculation of the plate crown and flatness on the exit side of each stand shown in S5 is usually performed by a plate crown prediction model (Expression (1)) and a flatness prediction model (Expression (2)) shown in the following equations. Is used by combining the deformation of the roll and the deformation of the rolled material by a theoretical analysis method generally called a split model.
(Number _{1) Cr i = α × Cr} Mi + (1-r i) × β × Cr i-1
(Number _{2) Δε i = ξ × (} Cr i / H i -Cr i-1 / H i-1)
_Here, Cr i, _{Cr i-1} is i, i-1 shows the stand delivery side strip crown, alpha represents the transfer rate, _{Cr Mi} represents the mechanical crown i stand, _{r i} is The stand rate of i-stand is shown, and β is a genetic coefficient. Δε _i indicates the flatness of the i stand exit side, H _i and H _i-1 indicate the plate thickness of the i, i-1 stand exit side, and ξ indicates the shape change coefficient.

The above-mentioned mechanical crown Cr _M is based on a deformation model of a rolling mill whose factors are deformation of the work roll due to rolling load, flatness, etc., and a roll profile model whose factors are initial profile, thermal expansion, wear, etc. of the work roll. Calculated. The transfer rate α is an influence coefficient of the mechanical crown with respect to the outgoing side plate crown, and the genetic coefficient β is an influence coefficient of the incoming side plate crown with respect to the outgoing side plate crown. The shape change coefficient ξ used when calculating the flatness Δε uses, as one embodiment of the present invention, a geometric parameter defined by the thickness of the rolled material, the plate width, and the roll diameter of the stand. The function expression was used.

  On the other hand, as a method for measuring the flatness of a plate in a hot rolling facility, a technique of measuring by an optical method using a laser and a monitor is known, but the flatness measurement by an optical method is performed by a tandem rolling mill 13. However, it is extremely difficult to measure the flatness of the stand on the way. By the way, the operator who operates the tandem rolling mill 13 determines the flatness based on the visual shape of the plate in the plate passing the rolled material through the rolling mill, and corrects it when the shape is disturbed. In addition, intervention is performed for the set value of the shape control device. Adjustment by this intervention is usually performed for a roll bending apparatus with good response. For example, when the plate shape is an ear wave, the pressure by the roll bending apparatus is increased until the plate is almost flat. On the contrary, if the plate shape is medium stretch, the pressure by the roll bending apparatus is decreased until it is flat.

  Here, in the adjustment by the operator, the accuracy of the operator's visual determination becomes a problem, but in the case of an experienced operator, the plate shape is accurately determined by visual adjustment and the pressure of the roll bending apparatus is adjusted, It is possible to avoid the trouble and correct the plate to have a good flatness. Therefore, in one embodiment of the plate shape control method in the hot rolling according to the present invention, by the amount of intervention (adjustment amount) to the initial setting value of the roll bending apparatus performed by the operator by looking at the plate shape, The flatness of the plate such as medium elongation is evaluated. This intervention amount (adjustment amount) by the operator is hereinafter referred to as an operator adjustment amount ΔJ. In the embodiment of the sheet shape control method in the hot rolling according to the present invention, the intervention amount (adjustment amount) to the initial set value of the roll bending apparatus is used as the operator adjustment amount ΔJ. Use the amount of intervention (adjustment amount) for the initial setting values of plate shape control devices such as roll shift devices and cross angle setting devices for pair cross mills instead of the amount of intervention (adjustment amount) for the initial setting values of the device. Of course it is also possible. That is, as the operator adjustment amount when the operator manually adjusts, the setting value of the plate shape control device for controlling the plate shape of the roll bending device, the roll shift device, the cross angle setting device of the pair cross mill, etc. is manually set. It is possible to use an operator adjustment amount at the time of adjustment.

  FIG. 4 is a diagram showing the relationship between the predicted value Δε of flatness obtained from the conventional equations shown in Equations (Equation 1) and Equation (Equation 2) without correction by the operator adjustment amount ΔJ, and the operator adjustment amount ΔJ. is there. As shown in FIG. 4, a positive correlation is recognized between the predicted value Δε of flatness obtained from the conventional equations shown in the equations (Equation 1) and (Equation 2) and the operator adjustment amount ΔJ. . Generally, when the predicted shape of the plate is an ear wave, the operator tends to adjust the pressure setting value by the roll bending device to the increasing side, and when the predicted shape of the plate is medium extension, the operator tends to adjust the pressure setting value to the decreasing side. Shows that the shape of the plate is correctly predicted qualitatively by visual inspection. However, the correlation between the flatness predicted value Δε and the operator adjustment amount ΔJ is not good. In contrast, the first to third embodiments using the three flatness prediction models according to the present invention will be described below. The flatness prediction model is not limited to these three models, and the flatness can be predicted using another flatness prediction model and the operator adjustment amount ΔJ.

(First embodiment)
The first embodiment of the method for controlling the plate shape in hot rolling according to the present invention uses a sheet crown prediction model represented by Equation (Equation 1) and a flatness prediction model represented by Equation (Equation 2). Based on the rolling performance when there is an intervention amount (adjustment amount) to the initial setting value of the bending device, the shape is such that the absolute value of the correlation coefficient between the operator adjustment amount ΔJ and the predicted flatness value Δε increases. A flatness predicted value calculation step of determining a change coefficient ξ and calculating a determined value of the flatness predicted value using this ξ is performed. Here, FIG. 3 is a flowchart showing a procedure for calculating a predicted value of the plate crown and the flatness of the plate shape control method in the hot rolling according to the present invention. FIG. 5 is a diagram showing the relationship between the flatness predicted value Δε calculated by the method according to the first embodiment of the present invention and the operator adjustment amount ΔJ.

As shown in FIG. 3, first, step 11 for inputting the operator adjustment amount ΔJ is performed. Then, provisional determination of the shape change coefficient ξ is performed in step 12. Next, step 13 of calculating the predicted value of the plate crown (plate crown predicted value calculating step) and calculating the predicted value of flatness using the plate crown predicted model and the flatness predicted model are performed. Here, in 1st Embodiment of the plate shape control method in the hot rolling which concerns on this invention, the plate crown prediction model shown to Formula (Equation 1) and the flatness prediction model shown to Formula (Equation 2) were used. In S12, for example, ξ ^* = ξ {1 + f (H, W,...)} (Ξ ^* : corrected shape change coefficient, H: plate thickness, W: plate width) A correction term f (H, W,...) Is introduced into the correction value, and the corrected shape change coefficient ξ is set so that the absolute value of the correlation coefficient between the operator adjustment amount ΔJ and the predicted flatness value Δε is increased in step 14. ^{* Is} determined. As an example, the correction term f (H, W,...) Is changed to a plate thickness H or a plate width W such that f (H, W,...) = A ₀ + a ₁ × H + a ₂ × W +. The coefficients a ₀ , a ₁ , a ₂ ,... Can be easily determined by the least square method. Thereafter, in step 15, a determined flatness predicted value is calculated using the determined corrected shape change coefficient ξ ^* (flatness predicted value calculating step). The corrected shape change coefficient ξ ^* may be obtained by introducing the correction term f (H, W,...) As described above, or the thickness, width, and stand of the rolled material. Depending on the roll diameter, etc., it may be completely defined. After that, in S7 shown in FIG. 2, the setting values of the plate shape control devices of each stand such as the roll bending device, the roll shift device, and the cross angle setting device of the pair cross mill are calculated.

  As shown in FIG. 5, the flatness prediction value Δε corrected by the operator adjustment amount ΔJ using the plate crown prediction model shown in the equation (Equation 1) and the flatness prediction model shown in the equation (Equation 2), and the operator The correlation with the adjustment amount ΔJ is higher than the correlation between the flatness predicted value Δε obtained from the conventional equation shown in FIG. 4 and the operator adjustment amount ΔJ.

(Second Embodiment)
As shown in the formula (Equation 1), if the error of the predicted value of the crown calculated from the predicted crown model of the crown has an error in the prediction accuracy of the mechanical crown for each stand, i stand, i + 1 stand, Errors gradually accumulate. In addition, there may be a large difference in the prediction accuracy of the roll profile for each stand. In this case, when the flatness of the plate is obtained by the amount of change in the plate crown ratio between the stands represented by the formula (Equation 2) as in the conventional case, the accuracy of the flatness prediction may deteriorate. Therefore, in the second embodiment of the plate shape control method in the hot rolling according to the present invention, instead of the equation (Equation 2), as shown in the following equation, the plate of the rolled material rolled into the n-1st sheet A flatness prediction model for predicting the flatness based on the difference between the crown ratio and the sheet crown ratio of the n-th rolled material was used. Thereby, the prediction error of the mechanical crown can be canceled.
(Equation 3) Δε = ξ × (Cr ⁿ / H ⁿ −Cr ⁿ⁻¹ / H ⁿ⁻¹ )
Here, [Delta] [epsilon] represents the flatness of the stand outlet ^side, Cr n, ^{Cr n-1} is, n, indicates a stand delivery side of the strip crown upon the rolling of the n-1 -th ^plate, H n, ^{H n -1} indicates the thickness of the stand exit side during rolling of the n, n-1th plate, and ξ indicates the shape change coefficient. Other plate crown predicted value calculation step, flatness predicted value calculation step, control device set value calculation step and the like in the second embodiment are the same as those in the first embodiment, and the tandem rolling mill 13 is operated. The flatness of the plate is evaluated based on the amount of operator adjustment when the operator manually adjusts. However, when the plate widths of the rolled material rolled to the n-1th and the rolled material rolled to the nth are different, in the evaluation point of the flatness of the rolled material rolled to the nth, the n-1st The sheet crown ratio of the rolled material is determined.

  Next, FIG. 6 is a diagram showing the relationship between the flatness predicted value Δε and the operator adjustment amount ΔJ according to the second embodiment of the present invention. As shown in FIG. 6, the flatness prediction value Δε corrected by the operator adjustment amount ΔJ using the plate crown prediction model shown in Expression (1) and the flatness prediction model shown in Expression (3), and the operator The correlation between the adjustment amount ΔJ is the correlation between the predicted value Δε of flatness obtained from the conventional equation shown in FIG. 4 and the operator adjustment amount ΔJ, and the plate of the equation (Equation 1) shown in FIG. Using the crown prediction model and the flatness prediction model of Equation (2), the correlation between the predicted flatness value Δε corrected by the operator adjustment amount ΔJ and the operator adjustment amount ΔJ is higher.

(Third embodiment)
In the third embodiment of the plate shape control method in hot rolling according to the present invention, the definition from the amount of change in the plate crown ratio before and after the conventional i-stand shown in Equation (2), and Equation (3) The flatness prediction model shown in the following equation is used, which combines the plate crown ratio of the rolled material rolled in the (n-1) th line and the definition from the difference between the sheet crown ratio of the rolled material rolled in the nth line. Is.
(Number _{4) Δε i = ξ × {} (Cr i n / H i n -Cr i n-1 / H i n-1) - (Cr i-1 n / H i-1 n -Cr i-1 n ^-1 / H _i-1 ^n-1 )}
Here, [Delta] [epsilon] _i is, i stand delivery side of the shows the ^{_{flatness, Cr i n, Cr i n}} -1, Cr i-1 n, Cr i-1 n-1 is, n, n-1 -th plate of i during rolling, i-1 shows the stand delivery side of the strip ^{_{crown, H i n, H i n}} -1, H i-1 n, H i-1 n-1 is, n, n-1 -th of The plate | board thickness of the i and i-1 stand exit side at the time of rolling of a board | plate is shown, (xi) shows a shape change coefficient.

  Here, also in the third embodiment, the plate crown predicted value calculating step, the flatness predicted value calculating step, the control device set value calculating step, and the like are the same as in the first embodiment, as in the second embodiment. The flatness of the plate is evaluated based on the amount of operator adjustment when the operator operating the tandem rolling mill 13 manually adjusts. Similarly to the second embodiment, when the plate widths of the rolled material rolled to the n-1th and the rolled material rolled to the nth are different, the flatness of the rolled material rolled to the nth roll At the evaluation point, the plate crown ratio of the rolled material rolled at the (n-1) th is obtained.

  FIG. 7 is a diagram showing a relationship between the flatness predicted value Δε and the operator adjustment amount ΔJ according to the third embodiment of the present invention. Table 1 below shows a comparison of correlation coefficient R values between the flatness predicted value Δε and the operator adjustment amount ΔJ in the conventional method, the first embodiment, the second embodiment, and the third embodiment. Is. As shown in FIG. 7 and Table 1, the correlation between the flatness prediction value Δε corrected by the operator adjustment amount ΔJ using the flatness prediction model shown in the equation (Equation 4) and the operator adjustment amount ΔJ is Correction was made by the operator adjustment amount ΔJ using the correlation between the flatness prediction value Δε obtained from the conventional method shown in FIG. 4 and the operator adjustment amount ΔJ and the flatness prediction model of the equation (Equation 2) shown in FIG. It is higher than the correlation between the flatness predicted value Δε and the operator adjustment amount ΔJ. Further, although slightly, it is higher than the correlation between the flatness prediction value Δε corrected by the operator adjustment amount ΔJ using the flatness prediction model of the equation (Equation 3) shown in FIG. 6 and the operator adjustment amount ΔJ. .

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

It is a schematic diagram which shows a hot rolling installation. It is a flowchart figure which shows the procedure which calculates the various setting values of a tandem rolling mill. It is a flowchart figure which shows the predicted value calculation procedure of a plate crown and flatness. It is a figure which shows the relationship between predicted value (DELTA) epsilon of flatness calculated | required from the conventional formula shown to Formula (Formula 1) and Formula (Formula 2), and operator adjustment amount (DELTA) J. It is a figure which shows the relationship between predicted value (DELTA) epsilon of flatness and operator adjustment amount (DELTA) J which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between predicted value (DELTA) epsilon of flatness and operator adjustment amount (DELTA) J which concerns on 2nd Embodiment of this invention. It is a figure which shows the relationship between predicted value (DELTA) epsilon of flatness which concerns on 3rd Embodiment of this invention, and operator adjustment amount (DELTA) J.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot rolling equipment 6 Steel plate 11 Heating furnace 12 Rough rolling mill 13 Tandem rolling mill 14 Cooling equipment 15 Winding machine

Claims (4)

A method for controlling the plate shape of a rolled material that is hot-rolled by a tandem rolling mill having a plurality of rolling stands arranged in series,
_{Cr i = α × Cr Mi +} (1-r i) × β × Cr i-1 (Cr i, Cr i-1: i, i-1 stand out side of the plate crown, α: the transfer rate, _{Cr Mi:} a plate crown predicted value calculating step of calculating a plate crown predicted value of the rolled material by a plate crown predicted model represented by a mechanical crown of i stand, r _i : rolling reduction of i stand, β: genetic coefficient),
The set value of the plate shape control device for controlling the plate shape, the operator adjustment amount when the operator operating the tandem rolling mill is manually adjusted, and the flatness prediction value calculated by the flatness prediction model A flatness predicted value calculation step of calculating a determined value of the flatness predicted value by the flatness predicted model using a shape change coefficient determined so that the absolute value of the correlation coefficient with
A control device set value calculation step of calculating a set value of the plate shape control device using the predicted value of the plate crown and the determined value, and a plate shape in hot rolling, Control method. The flatness prediction _{model, Δε i = ξ × (Cr} i / H i -Cr i-1 / H i-1) (Δε i: i stand delivery side _{flatness, Cr i, Cr i-1} : i , I-1 stand exit side plate crown, H _i , H _i-1 : i, i-1 stand exit side plate thickness, ξ: shape change coefficient). A method for controlling the plate shape in hot rolling as described in 1 above. The flatness prediction model is expressed as Δε = ξ × (Cr ⁿ / H ⁿ −Cr ⁿ⁻¹ / H ⁿ⁻¹ ) (Δε: flatness on the stand exit side, Cr ⁿ , Cr ⁿ⁻¹ : n, n− The crown of the stand exit side during rolling of the first plate, H ⁿ , H ^n-1 : n, the thickness of the stand exit side during rolling of the n-1 plate, ξ: shape change coefficient) The method for controlling a plate shape in hot rolling according to claim 1, wherein: The flatness prediction ^{_{model, Δε i = ξ × {(}} Cr i n / H i n -Cr i n-1 / H i n-1) - (Cr i-1 n / H i-1 n -Cr i ^{_{-1 n-1 / H i-}} 1 n-1)} (Δε i: i stand delivery side ^{_{flatness, Cr i n, Cr i n}} -1, Cr i-1 n, Cr i-1 n-1 : N, n-1 The plate crown of the i, i-1 stand exit side at the time of rolling the plate, H _i ⁿ , H _i ^n-1 , H _i-1 ⁿ , H _i-1 ^n-1 : n The plate in the hot rolling according to claim 1, wherein i, i-1 stand thickness at the time of rolling the n−1th plate, ξ: shape change coefficient). Shape control method.

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