JP2005319492A - Method for controlling shape in cold rolling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method which can manufacture rolled products having the excellent shape accuracy at high productivity by suppressing the generation of the edge wave even when thin plates are manufactured by cold rolling. <P>SOLUTION: This method preliminarily prepares a mathematical model for representing the difference in the elongation percentage with respect to the middle of the plate width at a plurality of positions at different distances from the plate end at the exit side of a final stand taking a rolling load at the final stand of a tandem rolling machine, a controlled variable of a shape control means, and a material crown as variables, and a mathematical model for representing the difference in the elongation percentage with respect to the middle of the plate width at the position in the neighborhood of the plate end at the exit side of the final stand taking rolling loads at respective stands, the controlled variable of the shape control means, and a edge drop of the blank before rolling as variables. Then, the control variables of the shape control means at respective stands are set such that the difference of the elongation percentage coincides with the target value by substituting the estimated values of the rolling loads at respective stands, the measured values of the crown and the edge drop of the blanks before rolling into the two mathematical models described above. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for controlling rolling conditions in a cold tandem rolling mill so that the plate shape of a rolled metal strip matches a target shape.

In cold tandem rolling, the shape of the rolled material being measured is measured with a shape detector placed on the exit side of the final stand, and the control amount of the shape control means such as roll bender and roll shift of the final stand is determined based on the measurement results. A correction method is generally employed (for example, Non-Patent Document 1).
In this shape control, the shape is usually evaluated by the difference in elongation with respect to the center of the plate width of a plurality of locations at different distances from the plate edge, and the difference in elongation is controlled so as to match the target value. As for the difference in elongation, the value is almost as intended. However, in the case of a thin plate with a thickness of 0.5 mm or less, even if the difference in elongation at a plurality of locations is as intended, there is a shape defect called edge wave, in which the extreme vicinity of the plate edge is relatively elongated. It becomes easy.
Japan Iron and Steel Institute Joint Study Group, Rolling Theory Division, “Theory and Practice of Sheet Rolling”, Japan Iron and Steel Institute, September 1, 1984, p308-313

Since this edge wave is a local extension near the end of the plate, it is difficult to correct it by the shape control means in the final stand. That is, if it is attempted to suppress local elongation in the vicinity of the plate edge by shape control means such as a roll bender or roll shift, medium elongation is likely to occur, and it is difficult to obtain a good shape over the entire plate width.
In addition, many shape detectors that measure the tension distribution by the contact-type split roll method are used. However, since each division width has a certain width, it is locally located near the plate edge. Elongation is often not detected. Therefore, even if the shape measured by the shape detector is good, the actually obtained shape may cause a large edge wave.
The present invention has been devised to solve such problems, and preset control and rolling using a mathematical model that takes into account the effect of edge drop on the elongation difference with respect to the center of the plate width near the plate end. It is an object of the present invention to provide a control method capable of suppressing the generation of edge waves by controlling the shape inside and producing a rolled material with excellent shape accuracy with high productivity.

  In order to achieve the object of the shape control method of the present invention, the distance from the end of the plate on the exit side of the final stand is a variable with the rolling load of the final stand of the tandem rolling mill, the control amount of the shape control means, and the crown of the material before rolling as variables. Mathematical model representing the difference in elongation from the center of the plate width at different locations, and the rolling load of each stand, the control amount of the shape control means, and the edge drop of the material before rolling as variables, the position near the plate end on the final stand exit side A mathematical model representing the difference in elongation relative to the center of the sheet width is created in advance, and the predicted value of the rolling load of each stand and the measured values of the crown and edge drop of the material before rolling are substituted into the two mathematical models, and the difference in elongation is The control amount of the shape control means of each stand is set so as to coincide with the target value.

  In addition, the elongation difference with respect to the center of the plate width at multiple locations at different distances from the plate edge on the final stand exit side, with the rolling load of the final stand of the tandem rolling mill, the control amount of the shape control means and the crown of the material before rolling as variables. A mathematical model representing the elongation difference with respect to the center of the plate width at the position near the end of the plate on the final stand exit side using the rolling load of each stand, the control amount of the shape control means and the edge drop of the material before rolling as variables. As well as creating, the rolling load of each stand, the crown and edge drop of the material before rolling are continuously measured, and these measured values are substituted into the two mathematical models so that the difference in elongation matches the target value. The control amount of the shape control means of each stand is corrected.

  Furthermore, a mathematical model representing the amount of change in the elongation difference with respect to the center of the plate width at the position near the end of the plate on the final stand exit side is created in advance using the amount of change in the shape control means of each stand of the tandem rolling mill as a variable. When correcting the control amount of the shape control means of the final stand based on the shape measurement result of the rolled material obtained by the shape detector installed on the exit side, this correction amount is substituted into the mathematical model, The control amount of the shape control means of the stand up to the last one stage is corrected so that the difference in elongation at the vicinity position matches the target value.

  In the present invention, preset control and shape control during rolling are performed using a mathematical model that takes into account the effect of edge drop on the elongation difference with respect to the center of the plate width near the plate end. For this reason, even if it is a thin material which is easy to generate | occur | produce an edge wave, generation | occurrence | production of an edge wave can be suppressed and the rolling material excellent in the shape precision can be manufactured with high productivity.

The present inventors set up and correct the control amount of the shape control means using a mathematical model that considers the effect of edge drop on the elongation difference with respect to the center of the plate width in the vicinity of the plate edge, thereby generating edge waves. The shape control method in cold tandem rolling was investigated and examined so that a good shape could be obtained over the entire length of the coil.
As a result, paying attention to the fact that the elongation difference with respect to the center of the plate width in the vicinity of the plate edge is linearly related to the rolling load of each stand, the control amount of the shape control means, and the edge drop of the material before rolling, and incorporate these effects. It has been found that when a mathematical model is used, the control amount of the shape control means can be set and corrected with high accuracy, and a rolled material having a good shape can be produced.

In the following, the control method of the present invention is described for a six-high rolling mill having a work roll bender, an intermediate roll bender and an intermediate roll shift as shape control means, but only some of the shape control means are provided. Of course, the present invention is similarly applied to a six-high rolling mill and a four-high rolling mill.
Since the edge wave is a local shape defect in the vicinity of the plate edge, the difference in elongation with respect to the plate width center near the plate edge corresponding to the edge wave and the plate width center of the portion closer to the plate width center side than that. The mathematical model is expressed by dividing the difference in elongation.

As for the shape of the portion on the center side of the plate width from the edge wave generation position, it prevents not only simple shape defects such as ear elongation and middle elongation, but also complex elongation that is a complex combination of quarter elongation and various elongations. Therefore, it is required to evaluate and control the rolling shape with a plurality of indices. Therefore, in the present invention, the rolling shape is evaluated by the difference between the elongation rate at a plurality of locations at different distances from the plate edge and the elongation rate at the center of the plate width.
Specifically, the rolling shape is defined by elongation difference ε _e and ε _q with respect to the plate width center of the plate end portion and the quarter portion. The position referred to as the plate end is a position on the center side of the plate width from the position near the plate end corresponding to the edge wave.

Elongation difference epsilon _e, epsilon _q, when the el _c elongation of el _e, el _q, sheet width central portion of the growth rate quota portion elongation of the plate ends, respectively formula (1) and ( 2).
ε _e = el _e -el _c (1)
ε _q = el _q −el _c (2)
Note that the positions of the plate end portion and the quarter portion are determined empirically so as to appropriately represent the shape and obtain an accurate mathematical model.

  Except for the position near the plate edge corresponding to the edge wave, the factors affecting the shape of the rolled material include the rolled material size, material, lubrication state, rolling load of the final stand, control amount of the shape control means, and before the final stand rolling. There are plate crown, plate shape before final stand rolling. Of these, regarding the rolled material dimensions, if the table is divided for each plate thickness and width, the influence of changes in the rolled material size within the sections on the shape can be reduced. As for the plate shape before the final stand rolling, when the rolling rate is relatively large like cold tandem rolling, the influence is small and can be ignored. The material and lubrication state affect the shape of the rolled material, but most of the influence is caused by changes in roll deflection through the rolling load. Therefore, it can be said that the main factors affecting the shape change are the rolling load of the final stand, the control amount of the shape control means, and the plate crown before the final stand rolling. Accordingly, the quantitative effects of the rolling load on the final stand, the control amount of the shape control means, and the crown before the final stand rolling on the rolling shape were examined.

The change in rolling load appears as a change in roll deflection and changes the shape of the rolled material. The relationship between the rolling load and the amount of bending of the roll is substantially linear because it is intended for deformation in the elastic region. Therefore, the elongation differences ε _e and ε _q represented by the equations (1) and (2) are also linearly related to the rolling load P as shown in FIG.
Similarly to the rolling load, the work roll bender and the intermediate roll bender change the rolling shape by changing the roll deflection. As shown in FIGS. 2 and 3, the work roll bender and the intermediate roll bender have an elongation difference ε. There is also a linear relationship between _e and ε _q . The intermediate roll shift changes the rolling shape by changing the roll deflection by changing the contact range between the rolls. In a narrow shift amount range, as shown in FIG. 4, the elongation difference ε _e , ε _It is almost linearly related to _q .

The plate crown before the final stand rolling was defined by a difference in plate thickness between a predetermined position of the plate end and the plate width center. The predetermined position is determined empirically so as to appropriately represent the plate crown before the final stand rolling and obtain an accurate mathematical model. As shown in the equation (3), the plate Cr ₁ before the final stand rolling is substantially equal to the value obtained by multiplying the crown Cr ₂ of the raw material before rolling by the total rolling reduction r up to the final stand entry side.
Cr ₁ = Cr ₂ · r (3)

Further, as shown in FIG. 5, the crown Cr ₁ before the final stand rolling and the elongation difference ε _e , ε _q are also in a linear relationship.
Therefore, the elongation differences ε _e and ε _q can be predicted by the following equations (4) and (5).
ε _e = a _e · P _n + b _e · W _n + c _e · I _n + d _e · δ _n + e _e · Cr ₁ + f _e (4)
ε _q = a _q · P _n + b _q · W _n + c _q · I _n + d _q · δ _n + e _q · Cr ₁ + f _q (5)
In the formula, n number of stands, P _n is the rolling load of the final stand, W _n is the controlled variable of the work roll bender of the final stand, I _n the control amount of the intermediate roll bender of the final stand, [delta] _n is the final stand intermediate Control amount of roll shift, a _e , b _e , c _e , d _e , e _e , f _e , a _q , b _q , c _q , d _q , e _q , f _q indicate influence coefficients.

Influence coefficients a _e , b _e , c _e , d _e , e _e , f _e , a _q , b _q , c _q , d _q , e _q , and f _q are production types such as plate width, plate thickness, and material. It is a constant determined according to the above, and is obtained from an experiment or a simulation based on an analysis model in which an elastic deformation analysis of a roll and a plastic deformation analysis of a material are coupled. Each influence coefficient is set in a table for each section such as a plate width, a plate thickness, and a material, or expressed as a function as a function of the plate width, the plate thickness, the material, and the like.

Next, the shape in the vicinity of the plate end corresponding to the edge wave is evaluated by the difference ε _w between the elongation at the position near the plate end and the elongation at the center of the plate width. The elongation difference ε _w is expressed by Expression (6), where e _w and el _c are elongation ratios in the vicinity of the plate end and the center of the plate width.
ε _w = el _w −el _c (6)
Note that the position near the plate end is selected empirically so as to appropriately represent the shape and to obtain an accurate mathematical model.

  Main factors affecting the shape change near the edge of the plate corresponding to the edge wave As well as the main factors affecting the shape change of the portion on the center side of the plate width from the position where the edge wave occurs, the rolling load and shape control of the final rolling stand It can be said that the control amount of the means and the edge drop before the final stand rolling. Therefore, the quantitative influence of the rolling load of the final stand, the control amount of the shape control means, and the plate edge drop before the final stand rolling on the rolling shape in the vicinity of the plate end was examined.

As shown in FIGS. 6 to 9, the elongation difference ε _w has a substantially linear relationship with the rolling load of the final stand, the work roll bender, the intermediate roll bender, and the intermediate roll shift, similarly to the elongation differences ε _e and ε _q .
Further, the plate edge drop before the final stand rolling was defined by the plate thickness difference between the position corresponding to the elongation difference ε _w and the position corresponding to the elongation difference ε _e . The edge drop before rolling of the final stand has a substantially linear relationship with the rolling load, the control amount of the shape control means, and the edge drop of the material before rolling in the stand up to one stage before the final stand. And as shown in FIG. 10, elongation rate difference (epsilon) _w has a substantially linear relationship with the plate edge drop before final stand rolling. Therefore, the elongation difference ε _w has a substantially linear relationship with the rolling load, the control amount of the shape control means, and the edge drop of the material before rolling, up to one stage before the final stand.

式中、Ｐ_iは各スタンドの圧延荷重，Ｗ_iは各スタンドのワークロールベンダーの制御量，Ｉ_iは各スタンドの中間ロールベンダーの制御量，δ_iは各スタンドの中間ロールシフトの制御量，Ｅ_dは圧延前素材のエッジドロップ，ａ_wi，ｂ_wi，ｃ_wi，ｄ_wi，ｅ_w，ｆ_wは影響係数を示す。 Therefore, the elongation difference ε _w can be predicted by the following equation (7).

Where P _i is the rolling load of each stand, W _i is the control amount of the work roll bender of each stand, I _i is the control amount of the intermediate roll bender of each stand, and δ _i is the control amount of the intermediate roll shift of each stand. , E _d is an edge drop of the material before rolling, a _wi , b _wi , c _wi , d _wi , e _w , and _fw are influence coefficients.

Influence coefficient _{a wi, b wi, c wi} , d wi, e w, f w is the plate width, a constant determined depending on the manufacturing varieties such as thickness and material, experiments or roll elastic deformation analysis and materials They can be obtained from simulations using an analytical model coupled with plastic deformation analysis. Each influence coefficient is set in a table for each section such as a plate width, a plate thickness, and a material, or expressed as a function as a function of the plate width, the plate thickness, the material, and the like.

In initial setting of each shape control means in the tandem rolling mill, the rolling load of each stand is predicted. Then, the work roll bender, the intermediate roll bender and the intermediate roll bender in the final stand are set so that the elongation differences ε _e and ε _q represented by the equations (4) and (5) approach the target values ε _e ⁰ and ε _q ⁰ , respectively. Sets the control amount of roll shift.
Next, the set control amounts of the work roll bender, intermediate roll bender and intermediate roll shift of the final stand are substituted into Expression (7), and the elongation difference ε _w represented by Expression (7) is the target value ε. work roll bender in stand up one stage before the final stand so as to approach the _w ^0, sets the control amount of the intermediate roll bender and the intermediate roll shifting.
The predicted value of the rolling load is obtained by learning calculation from the actual value of the rolling load up to the coil. Moreover, the measured value in a previous process can be used about the crown and edge drop of the raw material before rolling.

Further, when shape control is performed by the feed forward method, the rolling load of each stand and the crown and edge drop of the material before rolling are continuously measured. The work roll bender, intermediate roll bender, and intermediate roll of the final stand are set so that the elongation differences ε _e and ε _q represented by the equations (4) and (5) approach the target values ε _e ⁰ and ε _q ⁰ , respectively. The shift control amount is always corrected.
Next, the corrected control amounts of the work roll bender, the intermediate roll bender and the intermediate roll shift of the final stand are substituted into Expression (7), and the elongation difference ε _w represented by Expression (7) is the target value ε _w. The control amount of the work roll bender, intermediate roll bender and intermediate roll shift in the stand up to one step before the final stand is always corrected so as to approach ⁰ . Here, an X-ray thickness gauge or the like that can move in the plate width direction is used to measure the crown and edge drop of the material before rolling.

この場合には、形状制御において一般に広く用いられている山登り探索法等により、エッジウェーブの発生位置よりも板幅中央側にある部分について、最終スタンド出側に設置された形状検出器で得られた圧延材の形状測定結果に基づいて最終スタンドのワークロールベンダー，中間ロールベンダー及び中間ロールシフト等形状制御手段の制御量を常時補正する。 Furthermore, in the case of shape control by the feedback method, since the change amount of the elongation difference ε _{w in} the vicinity of the plate thickness has a linear relationship with the change amount of the shape control means of each stand, instead of the equation (7) The shape prediction formula according to formula (8) is used.

In this case, it is obtained by a shape detector installed on the final stand exit side for the portion located on the center side of the plate width from the edge wave generation position by a hill-climbing search method or the like generally used in shape control. The control amount of the shape control means such as the work roll bender, the intermediate roll bender and the intermediate roll shift of the final stand is constantly corrected based on the shape measurement result of the rolled material.

Then, the correction amount is substituted into the equation (8), and in the equation (8), the work roll bender in the stand up to one step before the final stand so that the change amount Δε _w of the elongation difference ε _w becomes zero. The control amount of the roll bender and the intermediate roll shift is always corrected.
In Expression (7), the control amount of the work roll bender, the control amount of the intermediate roll bender, and the control amount of the intermediate roll shift of each stand are arbitrary so that the elongation difference ε _w becomes the target value ε _w ⁰ . Can be set or corrected in combination. However, in consideration of responsiveness, it is preferable to prioritize the control amount of the work roll bender and the intermediate roll bender over the intermediate roll shift.

In the above description, the rolling shape is defined by the elongation difference ε _e and ε _q with respect to the center of the plate width at the two points of the plate end portion and the quarter portion with respect to the portion on the center side of the plate width from the edge wave generation position. The control amount of the shape control means of the final stand is set or corrected. However, the present invention is not limited thereto, and the rolling shape can be similarly controlled when the rolling shape is defined by using the elongation difference with respect to the center of the plate width at three or more points along the plate width direction.

  Further, the target rolling mills are not limited to the shape control means such as the work roll bender, the intermediate roll bender, and the 6-high rolling mill and the 4-high rolling mill having the intermediate roll shift. Even when a 6-high rolling mill or a 4-high rolling mill that is not provided is used, the shape control means of each stand is determined using the same shape prediction formula as the equations (4), (5), (7), and (8). Control amount can be set or corrected.

  The optimum shape control method is preset control + feedforward control or preset control + feedback control. Preset control is for indispensably setting the control amount of each shape control means initially and performing shape control from the beginning of rolling. Further, during rolling, the rolling load and the profile of the material change, so the rolling shape also changes. Correspondingly, there are feedforward control and feedback control as control for correcting the control amount of each shape control means during rolling. The feedforward control has an advantage that the control time delay is less than the feedback control, but is likely to cause an error in the control model. In terms of accuracy, feedback control is superior.

Example 1 (preset control)
The shape control according to claim 1 was carried out when rolling the plain steel having a product plate thickness of 0.3 to 0.5 mm.
In this example, as shown in FIG. 11, a tandem rolling mill 5 having 4 stands 1 to 4 was used. The rolling conditions, the predicted value of the rolling load of each stand, and the profile information of the material before rolling were input to the host computer 9. In addition, about the predicted value of the rolling load of each stand, it estimated by learning calculation according to Formula (9).
P _i = (1−α) P _i ′ + αP _iLAST (9)
Here, P _i ′ is a predicted value of the rolling load of the i stand at the start of rolling of the previous coil predicted by learning calculation, and P _iLAST is an actual value of the rolling load of the i stand at the start of rolling of the previous coil. . In addition, α is a coefficient representing the ratio of incorporation of the actual value P _{iLAST into} the learning calculation, and α = 0.1 in this embodiment.
In the process computer 10, according to the information from the host computer 9 based on the influence coefficient obtained in advance for each product type, No. 4 is obtained from the equations (4), (5), and (7). The control amount of the shape control means 11 in 1-4 stands was calculated and preset.

For the portion corresponding to the start of rolling, the shape after rolling obtained in Example 1 is measured, and the larger difference Δε between the elongation difference ε _e , ε _q and the respective target values ε _e ⁰ , ε _q ^0. FIG. 12 shows the relationship between _eq and the difference Δε _w between the elongation difference ε _w and its target value ε _w ⁰ . On the other hand, without considering the position near the edge of the plate corresponding to the edge wave, the elongation difference ε _e , ε _{q in} the conventional method in which shape control is performed only on the portion on the center side of the plate width from the edge wave generation position. as each target value epsilon _e ^0, organizes the difference [Delta] [epsilon] _w the larger [Delta] [epsilon] _eq of the difference between the epsilon _q ^0, and elongation difference epsilon _w and the target value epsilon _w ^0, FIG both relationships 13 Shown in
As seen in FIGS. 12 and 13, since the shape in the vicinity of the plate end is not considered in the conventional method, the elongation difference ε _w tends to be larger than the target value ε _w ⁰ , and the difference Δε _w Sometimes exceeded 40 × 10 ⁻⁵ . In contrast, in the rolling shape obtained in Example 1, the difference [Delta] [epsilon] _w elongation difference epsilon _w and the target value epsilon _w ⁰ were not fall 15 × 10 ^-5 less.

Example 2 (feed forward control)
The edge drop control method according to claim 2 was carried out when rolling a normal steel having a product plate thickness of 0.3 to 0.5 mm.
In this example, a tandem rolling mill 5 having 4 stands 1 to 4 was used as shown in FIG. The rolling conditions were input to the host computer 9. After the start of rolling, the rolling load of each stand is continuously measured with a load meter 7 and the pre-rolling material profile of the steel plate 6 is continuously measured with an X-ray plate thickness meter 8 movable in the plate width direction. The measured value was input to the host computer 9.
In the process computer 10, according to the information from the host computer 9 based on the influence coefficient obtained in advance for each product type, No. 4 is obtained from the equations (4), (5), and (7). The control amount of the shape control means 11 in 1-4 stands was calculated and always corrected. In consideration of responsiveness, a work roll bender and an intermediate roll bender were used as shape control means.

The shape after rolling obtained in Example 2 is measured, and the larger difference Δε _eq between the elongation differences ε _e and ε _q and the respective target values ε _e ⁰ and ε _q ⁰ and the elongation difference ε _w. and it organizes the difference [Delta] [epsilon] _w between the target value epsilon _w ^0, showing the relationship between the two in Figure 15. On the other hand, without considering the position near the edge of the plate corresponding to the edged wave, the elongation difference ε _e , ε in the conventional method in which the shape control is performed only for the portion on the center side of the plate width from the position where the edge wave is generated _q and the respective target value epsilon _e ^0, organizes the difference [Delta] [epsilon] _w the larger [Delta] [epsilon] _eq of the difference between the epsilon _q ^0, and elongation difference epsilon _w and the target value epsilon _w ^0, FIG both relationships 16 shows.
As shown in FIGS. 15 and 16, since the shape in the vicinity of the plate end is not considered in the conventional method, the elongation difference ε _w tends to be larger than the target value ε _w ⁰ , and the difference Δε _w Sometimes exceeded 30 × 10 ⁻⁵ . In contrast, in the rolling shape obtained in Example 2, the difference [Delta] [epsilon] _w elongation difference epsilon _w and the target value epsilon _w ⁰ were not fall 15 × 10 ^-5 less.

Example 3 (feedback control)
The edge drop control method according to claim 3 was carried out when rolling a normal steel having a product plate thickness of 0.3 to 0.5 mm.
In this example, as shown in FIG. 17, a tandem rolling mill 5 having 4 stands 1 to 4 was used. The rolling conditions were input to the host computer 9. After the start of rolling, the control amounts of the work roll bender and the intermediate roll bender of the final stand were always corrected by the hill-climbing search method based on the shape measurement result of the rolled material obtained by the shape detector 12 installed on the final stand exit side. . Then, the correction amount is substituted into the equation (8), and in the equation (8), the work roll bender and the intermediate in the stand up to one step before the final stand so that the change amount Δε _w of the elongation difference ε _w becomes zero. The control amount of the roll bender was constantly corrected.

The shape after rolling obtained in Example 3 was measured, and the larger difference Δε _eq between the elongation differences ε _e and ε _q and the respective target values ε _e ⁰ and ε _q ⁰ and the elongation difference ε _w. and it organizes the difference [Delta] [epsilon] _w between the target value epsilon _w ^0, showing the relationship between the two in Figure 18. On the other hand, without considering the position near the edge of the plate corresponding to the edged wave, the elongation difference ε _e , ε in the conventional method in which the shape control is performed only for the portion on the center side of the plate width from the position where the edge wave is generated _q and the respective target value epsilon _e ^0, organizes the difference [Delta] [epsilon] _w the larger [Delta] [epsilon] _eq of the difference between the epsilon _q ^0, and elongation difference epsilon _w and the target value epsilon _w ^0, FIG both relationships 19 shows.
As shown in FIGS. 18 and 19, since the shape in the vicinity of the plate end is not considered in the conventional method, the elongation difference ε _w tends to be larger than the target value ε _w ⁰ , and the difference Δε _w Sometimes exceeded 40 × 10 ⁻⁵ . In contrast, in the rolling shape obtained in Example 2, the difference [Delta] [epsilon] _w elongation difference epsilon _w and the target value epsilon _w ⁰ were not fall 15 × 10 ^-5 less.

Graph showing the effect of rolling load of final stand on elongation difference ε _e , ε _q Graph showing the effect of work roll bender control amount on the final stand on elongation difference ε _e , ε _q Graph showing the influence of the control amount of the intermediate roll bender on the final stand on the elongation difference ε _e , ε _q A graph showing the effect of the control amount of the intermediate roll shift of the final stand on the elongation difference ε _e , ε _q Graph showing the effect of the crown before final stand rolling on the difference in elongation ε _e , ε _q Graph showing the effect of rolling load of final stand on elongation difference ε _w Graph showing the effect of the control amount of the work roll bender on the final stand on the elongation difference ε _w Graph showing the effect of the control amount of the intermediate roll bender on the final stand on the elongation difference ε _w Graph showing the influence of the control amount of the intermediate roll shift of the final stand on the elongation difference ε _w Graph showing the effect of edge drop before final stand rolling on elongation difference ε _w Tandem rolling mill used in Example 1 Difference between the shape obtained in Example 1 and the target shape The difference between the shape obtained by the conventional method and the target shape Tandem rolling mill used in Example 2 Difference between the shape obtained in Example 2 and the target shape The difference between the shape obtained by the conventional method and the target shape Tandem rolling mill used in Example 3 Difference between the shape obtained in Example 3 and the target shape The difference between the shape obtained by the conventional method and the target shape

Explanation of symbols

1-4: Stand 5: Tandem rolling mill 6: Steel plate 7: Load meter
8: X-ray thickness gauge 9: Upper computer 10: Process computer
11: Shape control means 12: Shape detector

Claims (3)

  Mathematical formula expressing the difference in elongation from the center of the plate width at multiple locations at different distances from the plate edge on the final stand exit side, with the rolling load of the final stand of the tandem rolling mill, the control amount of the shape control means, and the crown of the material before rolling as variables. A mathematical model that represents the difference in elongation from the center of the plate width at the position near the end of the plate on the final stand exit side is created in advance using the model and the rolling load of each stand, the control amount of the shape control means, and the edge drop of the material before rolling as variables. Substitute the predicted value of the rolling load of each stand and the measured values of crown and edge drop of the material before rolling into the two mathematical models, and control the shape control means of each stand so that the difference in elongation matches the target value. A shape control method in cold rolling characterized by setting an amount.   Mathematical formula expressing the difference in elongation from the center of the plate width at multiple locations at different distances from the plate edge on the final stand exit side, with the rolling load of the final stand of the tandem rolling mill, the control amount of the shape control means, and the crown of the material before rolling as variables. A model and a mathematical model representing the difference in elongation from the center of the plate width at the position near the end of the plate on the exit side of the final stand are created in advance using the rolling load of each stand, the control amount of the shape control means, and the edge drop of the material before rolling as variables. In addition, the rolling load of each stand, the crown and edge drop of the material before rolling are continuously measured, and these measured values are substituted into the above two mathematical models, so that the difference in elongation matches each target value. A shape control method in cold rolling, wherein the control amount of the shape control means is corrected.   A mathematical model representing the amount of change in the elongation difference with respect to the center of the plate width at the position near the end of the plate on the final stand exit side is created in advance using the change amount of the shape control means of each stand of the tandem rolling mill as a variable, When correcting the control amount of the shape control means of the final stand based on the shape measurement result of the rolled material obtained by the installed shape detector, this correction amount is substituted into the mathematical model, and the position near the plate edge is A shape control method in cold rolling, characterized in that the control amount of the shape control means of the stand up to the last one stage is corrected so that the difference in elongation matches the target value.

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