JPH1157827A - Edge drop control method for plate material rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an uniform thickness of the plate material in width direction by securely reducing an edge drop generated in the both material end portions of the plate material in the whole width direction. SOLUTION: In a process wherein a rolling is carried out by crossing a pair of upper and lower work rolls and, by shifting a work roll having a tapered part at its one end towards its axial direction, a roll gap reference point is set at a position apart from the end of the plate at a set distance and in reference to the above, the relationship between an effective roll gap and an adjusted value of an edge drop is predetermined and a target effective roll gap value for the improvement of the desired edge drop is calculated. Based upon the relatively in which the effective roll gap value is equal to the aggregate of the effective roll gap by the shifting only and that by the crossing only, a target shifting position and target crossing angle to satisfy the target roll gap are obtained. Rolling is conducted according to the target values obtained as above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling a sheet material, particularly when rolling a sheet material such as a steel sheet in cold rolling or the like, in which edge drop is improved and the thickness distribution in the width direction is made uniform over the whole. The present invention relates to an edge drop control method in sheet rolling.

[0002]

2. Description of the Related Art Among the thickness deviations in the width direction occurring in a sheet material (rolled material) during rolling, a sharp decrease in the thickness at both ends in the width direction is particularly called an edge drop. In order to obtain a good material to be rolled by rolling to make the thickness distribution uniform in the width direction, it is necessary to reduce the edge drop.

As one of the control methods for reducing the edge drop generated in such a plate material, a work roll (hereinafter, sometimes abbreviated as WR) having a tapered end on one side of a roll has been conventionally used. A method of shifting in the direction is used.

For example, in Japanese Patent Publication No. 2-34241, a work roll having a tapered end on one side is used to obtain a thickness profile (width distribution in the width direction) of a base plate at an entry side of a rolling mill. From the roll gap distribution between the upper and lower work rolls and the transfer rate of the roll gap distribution to the material to be rolled, the thickness profile on the rolling mill exit side is estimated, and the estimated value is compared with the target thickness profile, A method of shifting a work roll to a position where the difference between the two is minimized is disclosed.

[0005] Also, a document "Sheet crown / edge drop control characteristics" (Preprints of the 45th Lecture Meeting on Plastic Working, p. 40)
3-406, 1994), the upper and lower work rolls are crossed together with the backup rolls on each side, so that the plate thickness is formed between the upper and lower work rolls by a parabolic roll gap generated from the center in the width direction to the plate edge. It is disclosed that there is an effect of making the profile uniform.

As a technique combining a roll cloth and a roll shift for upper and lower work rolls, for example, Japanese Patent Application Laid-Open No. 57-206503 discloses a roll cross type rolling mill comprising an upper roll group and a lower roll group crossing at a predetermined angle. Discloses a technique for moving the relative position of a work roll in a roll group relative to a rolled material in the roll axis direction, thereby making the wear of the work roll uniform, reducing the frequency of roll polishing, and improving the unit consumption of the roll. Have been.

Japanese Patent Application Laid-Open No. 5-185125 discloses a method for reducing a defective area of a plate shape which occurs in a process of changing a roll cross angle when changing a running distance setting when a coil passes through a welding point (plate joint). A method of operating a roll shift and a work roll bend force in accordance with a change timing of a roll cross angle is disclosed. In this method, when the rolling conditions are significantly changed in the rolling of the welding point, which is a very limited portion of the coil, for the purpose of maintaining a good plate shape,
In the transitional state of the roll cross angle setting from the start of the change of the roll cross angle to the end of the change, the shift amount of the work roll is changed, and the relationship between the roll cross angle with respect to the preceding coil and the work roll bend force is shown. The work roll bend force is changed according to the optimum pattern so that the roll cross angle and the work roll bend force set from the optimum curve can be changed to the roll cross angle and the work roll bend force for the succeeding coil in the shortest time.

[0008]

However, in the techniques disclosed in Japanese Patent Publication No. 2-34364 and Japanese Patent Publication No. 2-34241, the taper of the work roll is provided by polishing before rolling. It is impossible to change the amount or shape of the taper inside. Usually, the work roll is not replaced for each rolling material, but is used for rolling several tens of rolls. Therefore, when rolling several tens of rolled materials, the edge drop is not sufficiently improved for rolled materials with a large edge drop on the base plate, or the edge drop is improved for rolled materials with a small edge drop on the base plate. Becomes excessively large, causing problems such as an excessively thick plate end.

In the method disclosed in the above-mentioned document "Sheet Crown and Edge Drop Control Characteristics", a parabolic roll gap generated from the center of the sheet width toward the end of the sheet gradually expands. Although there is an effect of improving the (plate crown), there is a problem that the effect of reducing the edge drop which is a thickness deviation only at the end of the plate width is small.

Japanese Patent Publication No. 57-206503 is intended to prevent uneven wear of a work roll, and thus cannot directly control edge drop. The method described in Japanese Patent Publication No. 5-185125 is intended to prevent the deterioration of the plate shape during the transitional period of the change of the cross angle when rolling the welding point which is a part of the coil. With respect to the drop, there is a problem that the improvement effect beyond the conventional work roll shift disclosed in JP-B-2-4364 cannot be expected over the entire length of the coil.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an edge drop, which is a sharp reduction in the thickness generated at both ends in the width direction of a sheet material, is provided for various materials to be rolled. An object of the present invention is to provide an edge drop control method in sheet rolling, which can surely reduce the thickness and roll the sheet to a uniform thickness throughout the width direction.

[0012]

According to the present invention, there is provided a rolling machine having a mechanism for shifting a work roll having a tapered end at least on one side of the roll in the axial direction, and a mechanism for crossing a pair of upper and lower work rolls. An edge drop control method in sheet rolling when rolling using a mill, a roll gap reference position is set at a position separated by a predetermined distance from a plate edge, and the upper and lower work roll intervals based on the reference position are set as effective rolls. By setting the gap between the effective roll gap and the edge drop correction amount in advance, and setting or adjusting the shift position and the cross angle of the work roll based on the relationship to perform rolling, the problem is solved. Is solved.

According to a second aspect of the present invention, in the edge drop control method, an edge drop amount to be corrected is obtained from an actually measured plate profile on a rolling mill entry side and a target edge drop amount after rolling. Applying the relationship between the effective roll gap and the edge drop correction amount to the determined edge drop amount to be corrected, calculating the effective roll gap amount required to correct the edge drop amount to be corrected, The shift position and the cross angle that satisfy the effective roll gap amount are obtained, and the upper and lower work rolls are set at the shift position and the cross angle to perform rolling, thereby enabling high-accuracy edge drop control by setting control or feedforward control. It was done.

According to the present invention, in the above edge drop control method, a deviation between an actually measured edge drop amount measured on the exit side of the rolling mill during rolling and a target edge drop amount after rolling is obtained, By applying the relationship between the effective roll gap and the edge drop correction amount to the deviation, an effective roll gap change amount required to eliminate the deviation is calculated, and necessary to obtain the required effective roll gap change amount. The shift position change amount and the cross angle change amount are obtained, and the work roll shift position and the cross angle are adjusted to perform rolling, thereby enabling high-accuracy control of edge drop by feedback control.

According to the present invention, in the edge drop control method, the shift position and the cross angle of the work roll are set to predetermined values, respectively, and rolling is performed. The deviation between the measured edge drop amount measured in the above and the target edge drop amount after rolling is obtained, and the relationship between the effective roll gap and the edge drop correction amount is applied to the deviation, and the effective amount required to eliminate the deviation is obtained. The roll gap change amount is calculated, the shift position change amount and the cross angle change amount necessary to obtain the required effective roll gap change amount are obtained, and the work roll shift position and the cross angle are adjusted to perform rolling. Similarly, high-accuracy edge drop control by feedback control is enabled.

According to the present invention, in each of the edge drop control methods, at least two points for controlling the edge drop amount are provided on one side in the plate width direction, thereby achieving higher precision control. It was made possible.

First, as an example of a work roll used in the present invention, the concept of shift and cross for upper and lower work rolls having a tapered end on one side will be described.
This will be clarified with reference to FIGS.

As shown in FIG. 1, the shift is a work roll in which a taper is applied to one end of a point end symmetrical roll end between upper and lower work rolls, as conceptually shown in FIG. The shift amount is an amount by which the tapered work roll is moved in the axial direction.
This shift amount is, specifically, a distance EL from the plate end of the material S to be rolled to the tapered start end E as shown in FIG. 2 in which the vicinity of one end of the upper roll is enlarged. Further, the taper amount of the roll is defined by H / L, that is, tan α (α: taper angle) in FIG.

As shown in FIG. 3, a work roll in which the rolling mill is viewed from above is conceptually shown in FIG. Is half of the angle formed by the axes of

The inventors of the present invention have proposed a method as shown in FIG.
Using a rolling mill having upper and lower tapered work rolls with tapered one-side ends of the rolls in opposite directions, these upper and lower work rolls are shifted in the axial direction, and rolling is performed so that they cross each other. As a result,
Roll gap between upper and lower work rolls due to shift and cross (gap between upper and lower work rolls when there is no load)
However, it has been found that in the roll gap, only the portion near the plate edge is effective for improving the edge drop. At the same time, a reference position (hereinafter, also referred to as a roll gap reference position) is located at a predetermined distance from the plate edge.
It has been clarified that the relationship with the edge drop improvement amount (correction amount) can be well arranged by employing the effective roll gap obtained using the reference position as a reference (roll gap = 0). The present invention has been made based on the above findings.

Hereinafter, the basic principle of the present invention will be specifically described.

FIG. 4 shows a normal roll gap, which is defined as a gap (interval) between upper and lower work rolls under no load with reference to a roll profile of a mill center (center of a barrel). It is. In the figure,
The square is when the tapered work roll is shifted by 30 mm, the white circle is when the flat roll crosses the predetermined angle,
The black circles indicate each roll gap when the tapered work roll is shifted by 30 mm and crossed by the same angle.

In the present invention, a roll gap reference position as a reference point for edge drop control is provided at a position distant from the plate edge by a predetermined distance, for example, at a position 100 mm from the plate edge, and the upper and lower workpieces obtained with reference to this position are provided. The concept of the effective roll gap S defined by the gap between rolls, that is, the following formula (1), is newly adopted.

S = G15-G100 (1) G15: Roll gap at a position of 15 mm from the plate end (when no load is applied) G100: Roll gap at a position of 100 mm from the plate end (when no load is applied) Sometimes the sign is always plus)

FIG. 5 shows, as an example, 100 mm from the plate edge.
FIG. 6 conceptually shows an effective roll gap for the roll gap shown in FIG. 4 defined based on the position based on the actual value. From this figure, it can be seen that the effective roll gap when the upper and lower work rolls are shifted and crossed is represented by the sum of the effective roll gaps associated with each individual operation.

FIG. 6 shows the correlation between the effective roll gap and the edge drop improvement amount.

This relationship is established by using a rolling mill having upper and lower tapered work rolls having tapered one end portions of the rolls in opposite directions as shown in FIG. It is obtained based on actual measurement values that are investigated through a rolling experiment in which rolling is performed while shifting and crossing each other.

Here, the edge drop improvement amount refers to a flat roll (a shift amount of 0 mm,
This is a difference between the edge drop amount when rolling is performed at a taper work roll set at a cross angle of 0 °) and the edge drop amount when rolling is performed while setting a predetermined shift amount and a cross angle. Further, the edge drop amount used here is the same as the roll gap reference position, as a deviation between the plate thickness at the position 100 mm from the plate end and the plate thickness at a position 15 mm from the plate end. (2).

E15 = h15-h100 (2) h15: Plate thickness at a position of 15 mm from the plate end h100: Plate thickness at a position of 100 mm from the plate end

Therefore, when the sign of the edge drop amount E15 is minus, it means edge drop, and when the sign of E15 is plus, it means edge up.

The relationship shown in FIG. 6 shows that two types of tapered rolls having a taper amount of 1/500 and 1/250 are used as the work rolls, and the shift amount of the work rolls is within a range of 0 to 70 mm. The angle was determined from the result of rolling while changing to a predetermined value in the range of 0 to 0.8 °.

From the results shown in FIG. 6, there is a close correlation between the effective roll gap and the edge drop improvement amount. By adopting the effective roll gap in this manner, the edge drop improvement amount (correction amount) is obtained. It can be seen that the relationship with the can be well organized.

According to a first aspect of the present invention, rolling is performed by setting or adjusting a shift position and a cross angle of the work roll based on the above basic principle.

In this case, according to the invention of claim 2, first, the edge drop amount to be corrected is obtained from the measured plate profile on the entry side of the rolling mill and the target edge drop amount after rolling. Here, the edge drop amount to be corrected predicts the post-rolling edge drop amount when rolling with a flat roll from the input side measured thickness profile, and is given as a deviation between the edge drop amount and the target edge drop amount. .

Next, the relationship between the effective roll gap and the edge drop correction amount is applied to the obtained edge drop amount to be corrected, and the effective roll gap necessary to improve the edge drop amount to be corrected is applied. Based on the above-mentioned relationship that the effective roll gap amount when the work roll shift and the cross are used together is equal to the sum of the effective roll gap only by the shift and the effective roll gap by the cross only, the necessary effective Find the shift position and cross angle that satisfy the roll gap amount,
The upper and lower work rolls are set at the shift position and the cross angle to perform rolling. The specific procedure will be described together with the invention of claim 5 described later.

In the above description, 15 mm from the plate edge
I took up the edge drop amount at the position, but other than that,
For example, even at a position of 10 mm or 20 mm from the plate edge,
It has been confirmed that the correlation between the effective roll gap and the edge drop improvement amount is established. In addition, the reference position for determining the effective roll gap is not limited to the above-described position of 100 mm from the end of the plate, but depends on various conditions such as the thickness and deformation resistance of the material to be rolled, the roll diameter of the work roll, and the rolling load. Needless to say, it can be changed to an appropriate position.

Next, the invention of claim 3 will be described (the invention of claim 4 is basically the same).

In the present invention, similar to the second aspect of the present invention, the following control is performed using the basic principle of the first aspect of the present invention.

That is, a shift amount (position) and a cross angle are set to predetermined values for a pair of upper and lower work rolls having one end tapered as described above, and rolling is performed. Based on the edge drop amount measured on the rolling mill exit side at the time), feedback control for correcting the shift amount and the cross angle during rolling based on the following principle is performed.

FIG. 7 shows the relationship between the effective roll gap change δS and the edge drop change δED given by the following equations (3) and (4) when the shift position and the cross angle are changed during rolling. Is shown.

ΔS = S (a) −S (b) (3) δED = ED (a) −ED (b) (4) where S (b): effective roll gap before change S (a) ): Effective roll gap after change ED (b): Edge drop amount before change ED (a): Edge drop amount after change

The edge drop amount ED used here is the same as that defined in the above equation (2).
The sign is negative when the edge is dropping and positive when the edge is up.

As shown in FIG. 7, when the effective roll gap change amount δS is positive, that is, when the effective roll gap S increases, the edge drop change amount δED is positive, that is, the edge drop becomes small. That is, according to the above definition, a decrease in the edge drop amount means a decrease in the plate thickness deviation, and the amount has a positive value. Conversely, if the effective roll gap change amount δS is negative, that is, if the effective roll gap S decreases, the edge drop change amount δED becomes negative, that is, the edge drop increases. Also, as the change amount (change amount) of the effective roll gap increases, the change amount of the edge drop also increases.

In FIG. 7, the position of 15 mm from the edge of the plate is described as the amount of edge drop. However, the present invention is not limited to this. The relationship with the amount of change is established.

Therefore, the edge drop change amount with respect to the effective roll gap change amount is linearly approximated as shown by the broken line A in FIG. 7 and the slope is defined as an edge drop influence coefficient K. As described above, there is an almost linear relationship between the two, that changing the effective roll gap during rolling is equivalent to operating at the slope portion in the curve shown in FIG. In tandem rolling mills and the like, edge drop occurs in the rolling mill itself, and if the improvement of edge drop is increased in the preceding stand, the amount of edge drop generated in the subsequent stage tends to increase. It is thought that.

Next, a deviation between the edge drop amount ED (m) measured at the exit side of the rolling mill during rolling and a preset target edge drop ED (t) is defined as a required edge drop improvement amount ΔED. Is multiplied by the reciprocal of the influence coefficient K, the effective roll gap change amount ΔSb required for improving the edge drop can be obtained as shown below.

ΔED = ED (m) −ED (t) (5) ΔSb = ΔED / K (6)

Thereafter, the shift position and the cross angle of the upper and lower work rolls are adjusted (changed) so that the required effective roll gap change amount ΔSb obtained in this manner is obtained, so that the measured edge at the rolling mill exit side is measured. Feedback control can be performed so that the drop amount matches the target edge drop amount. The specific procedure for adjusting the cross angle at the shift position of the upper and lower work rolls will be described together with the invention of claim 5 described later.

The reference position of the effective roll gap used in the above description varies depending on various conditions such as the thickness and deformation resistance of the material to be rolled, the roll diameter of the work roll, and the rolling load. Similarly to the case, the position is not limited to the 100 mm position, and may be any distance from the plate edge that covers a range effective for improving the edge drop. Further, although the edge drop change amount with respect to the effective roll gap change amount is linearly approximated, the present invention is not limited to this, and may be nonlinearly approximated.

Next, the invention of claim 5 will be described.

First, the control executed based on claim 5 in the setting control or the feedforward control according to the invention of claim 2 will be described.

The present invention is based on the premise that the edge drop amount is controlled on the basis of the basic principle described above, and at least two control points are provided on one side in the plate width direction. This is a method of controlling edge drop.

Here, for convenience, a case in which there are two control points will be described with reference to the flowchart of FIG. 9 while referring to FIG.

In FIG. 8, the solid line A represents the thickness profile when rolling by a flat roll, and the broken line B represents the target plate profile.

First, as shown in FIG. 8, two control positions (points) x1 and x2 respectively located at predetermined distances from the plate edge are determined (set) (step 1). Next, the edge drop improvement amounts ΔE _x1 and ΔE _x2 required at the control points x1 and x2 are obtained (step 2). The edge drop improvement amount (correction amount) is an edge drop amount required to improve a thickness profile A obtained when rolling by flat rolls to a target plate profile B.

Next, a relationship between the effective roll gap and the edge drop improvement amount at the predetermined control points x1 and x2 as shown by curves C and D in FIG. 8 is prepared (step 3). Based on the relationships C and D, as shown in the figure, the effective roll gaps ΔS _x1 and ΔS _{x2 at} which the required edge drop improvement is obtained at the control points x1 and x2 are obtained (step 4).

The following relationship derived from the fact that the effective roll gap at the control points x1 and x2 can be expressed by the sum of the effective roll gap caused by shifting the tapered work roll and the effective roll gap caused by crossing. The shift amount (position) EL and the cross angle θ are obtained by substituting into equations (7) and (8) (step 5). For convenience, the method of deriving the equations (7) and (8) will be described later.

The work roll is shifted by the shift amount EL obtained in step 5 and the work roll is crossed at the cross angle θ, and rolling is performed under these conditions (steps 6 and 7).

EL = {(ΔS _x1 A2−ΔS _x2 · A1) −tan (α) (A2 × x1−A1 × 2)} / (A2−A1) (7) θ = tan ⁻¹ [｛(ΔS _{x1 -ΔS x2) - (x1-} x2)} / (A1 -A2) ] ^1/2 (8) where, A1 = 2 · {(2 / W-x1) 2 - (2 / W-1
00) ² ｝ / D _W A2 = 2 ｛(2 / W−x2) ² − (2 / W−10)
0) ² ｝ / D _W W: plate width (mm) D _w : work roll diameter (mm) tan (α): taper inclination (example: 1/300) Shift amount EL: for example, 100 mm or less x1: from plate edge Distance (control point) x2: Distance from plate edge (control point)

The above equations (7) and (8) are derived as follows.

First, at each of the control points x1 and x2,
As described above, since the effective roll gaps ΔS _x1 and ΔS _x2 can be expressed by the sum of the effective roll gap due to the shift at the same position and the effective roll gap due to the cross, respectively, the following (9A) and (9B) The relational expression of the expression is obtained.

ΔS _x1 = f _x1-100 (EL) + g _x1-100 (θ) (9A) ΔS _x2 = f _x2-100 (EL) + g _x2-100 (θ) (9B) f _x-100 ( EL): Effective roll gap by shifting 100 mm from the plate edge g _x-100 (θ): Effective roll gap by crossing 100 mm from the plate edge

The effective roll gap g _x-100 (θ) due to the cross can be expressed by the following equation (10).

G _x−100 (θ) = g _x (θ) −g ₁₀₀ (θ) = 2 · {(W / 2−x) ² − (W / 2−100) ² } · tan ² θ / D _W … (10)

In the equation (10), g _x (θ), g
₁₀₀ (θ) is a normal roll gap by a cloth with the mill center at xmm and 100 mm from the edge of the plate, respectively, and g _x (θ) can be expressed by the following equation (11).

G _x (θ) = 2 · (W / 2−x) ² · tan ² θ / D _W (11) θ: cross angle W: plate width D _W : work roll diameter x: from plate edge distance

On the other hand, the effective roll gap f due to the shift
_x-100 (EL) can be expressed by the following equation (12).

Fx _-100 (EL) = (EL−x) · tan (α) (12) EL: shift amount tan (α): taper inclination (ex.1 / 300) x: from the end of the sheet width Distance

The equations (9A) and (9B) are obtained by calculating the shift amount E
Equations (7) and (8) can be obtained by solving for L and the cross angle θ.

In actual control, the thickness profile when rolling by flat rolls is performed by a control device including a computer or the like based on rolling conditions and material conditions such as the thickness, rolling load, and edge drop amount of the base plate. Then, a model formula or a table is prepared in advance, and calculation is performed using the formula. Similarly, the relationship between the effective roll gap and the amount of edge drop improvement is modeled or tabulated in advance and held in the control device.

As described above, according to the first, second or first, second, or fifth aspect of the present invention, a mechanism for axially shifting a work roll having a tapered end at least on one side of the roll is provided. In performing the edge drop control of the sheet material using a rolling mill having a mechanism for crossing the work rolls, a reference position for edge drop control is provided at a position separated by a predetermined distance from the end of the sheet, and the reference position is set as a reference. Based on the relationship between the effective roll gap, which is the gap between the upper and lower work rolls, and the edge drop correction amount, the roll gap amount required to obtain the desired edge drop improvement is calculated, and the shift position is adjusted to be the roll gap amount. And the cross angle are set, so by setting control and feedforward control, for various base plate thickness profiles, The edge drop is a sudden thickness reduction occurring in both ends in the width direction of the timber can be reliably reduced, it becomes possible to roll to a uniform thickness over the entire width direction.

Next, in the feedback control according to the third or fourth aspect of the present invention, the control executed based on the fifth aspect will be described. However, here, for convenience, a case will be described as an example where two control points are set at different predetermined distances x1 and x2 from the plate edge as in the case described above.

A procedure for controlling based on the edge drop amount measured on the exit side of the rolling mill during rolling will be described with reference to FIG.

In FIG. 10, the curve denoted by the symbol A indicates the thickness profile measured on the exit side of the rolling mill. Here, two points x1 and x2 are set as the edge drop control points as described above.

The edge drop improvement amount (change amount) required to improve the thickness profile A to the target plate profile on the exit side of the rolling mill indicated by the dashed line with reference numeral B is the control point x1. ΔED _x1 and ΔED _x2 at the control point _x2 . Next, at the control points x1 and x2, the effective roll gap change amounts ΔSb _x1 and ΔSb required to obtain the required edge drop improvement amount from the relationship between the effective roll gap and the edge drop improvement amount, respectively.
_x2 is calculated by the following equation.

ΔSb _x1 = ΔED _x1 / K _x1 (13) ΔSb _x2 = ΔED _x2 / K _x2 (14) where K _x1 : edge drop influence coefficient at position x1 K _x2 : edge drop at position x2 Influence coefficient

A method of calculating the shift amounts EL and the change amounts ΔEL and Δθ of the cross angle θ for obtaining the effective roll gap change amounts at the above two points will be described below.

From the above-described definition formula of the roll gap, the effective roll gap change amount when the shift amount is changed by ΔEL and the effective roll gap change amount when the cross angle is changed by Δθ are respectively expressed by the following (15). formula,
It can be obtained by equation (16).

F _x−100 (ΔEL) = ΔEL · tan (α) (15) g _x−100 (Δθ) = 2 {(W / 2−x) ² − (W / 2−100) ² } × {Tan ² (θ−Δθ) −tan ² θ} / D _W (16)

The work roll shift position change amount ΔEL and the work roll cross angle change amount Δθ required to obtain the necessary roll gap change amounts ΔSb _x1 and ΔSb _x2 at the control points x1 and x2 are as described in the above (15). By solving the equations (16) and (16) simultaneously, the following equations (17) and (18) can be obtained. In addition, A1, A2
Is the same as in the above equations (7) and (8).

ΔEL = (A 2 · ΔSb _x1 −A 1 · ΔSb _x2 ) / {tan α · (A 2 −A 1)} (17) Δθ = tan ⁻¹ ((ΔSb _x1 −ΔSb _x2 )} (A ¹ −A ₂ ) −tan ² θ｝ ^1/2 −θ… (18)

As described above, claims 1 and 3 (4)
Alternatively, in the invention according to claims 1, 3 (4) and 5, the rolling mill includes a mechanism for shifting a work roll having a tapered end at least on one side of the roll in the axial direction, and a mechanism for crossing the work roll. In performing the edge drop control of the plate material by using a reference position for edge drop control at a position separated from the plate end by a predetermined distance, an effective roll gap which is a gap between the upper and lower work rolls based on the reference position. Based on the relationship between the edge drop correction amount and the amount of edge drop correction, the effective roll gap change amount required to obtain the desired edge drop improvement obtained from the measured edge drop amount on the rolling mill exit side and the target edge drop amount is calculated, and the necessary effective Since the shift position and the cross angle change amount that can obtain the roll gap change amount are obtained and adjusted respectively, the feed With the thickness control, it is possible to reliably reduce the edge drop, which is a sharp decrease in the thickness at both ends in the width direction of the material, for the material to be rolled with various thickness profiles, and to achieve a uniform thickness throughout the width direction. It became possible to roll to

[0083]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 11 is a side view, including a block diagram, showing a schematic configuration of a cold tandem rolling mill (rolling equipment) comprising six stands and applied to the first embodiment according to the first, second and fifth aspects of the present invention. It is.

In the tandem rolling mill, a shift operating device 12 for shifting the upper and lower work rolls 10 of the first stand to a predetermined position in the axial direction, a cross operating device 14 for crossing the upper and lower work rolls 10 at a predetermined angle, A first stand control device 20 that outputs a control signal to the operation devices 12 and 14 is provided.

The control device 20 includes a base plate thickness profile detecting device 16 installed on the exit side of the hot rolling mill in the preceding process.
When the information of the base plate thickness profile before rolling measured in step S1 and the target value after cold rolling set by the target value setting device 18 are input, the operation amount of the first stand is obtained. The shift amount and the cross angle are calculated, and the shift amount and the cross angle are output to the operating devices 12 and 14, respectively, so that the work roll 10 is shifted by a predetermined shift amount (position).
The rolling control is performed by setting the rolling angle to the cross angle.

The control device 20 holds data on the relationship between the predetermined effective roll gap amount and the edge drop correction amount. This relationship will be described later in detail.

In the present embodiment, the first stand is a four-high rolling mill including a work roll and a backup roll, and the upper and lower work rolls 10 are each provided with a taper at one end at a point symmetrical position. Each of the upper and lower work rolls 10 is supported by a backup roll 22 from above and below, so that only the upper and lower work rolls cross each other. The work roll diameter of the first stand is 570 mm, and the taper amount of the work roll is 1/300.

Next, the operation of the present embodiment will be described.

The rolled material was pickled after rolling and the sheet width was 900 m.
m for tin plate, edge drop control point is 10mm position (x1 point) and 30mm position (x2 point) from plate edge
In each of the two points, the target edge drop amount at each control point is 0 μm.

FIG. 12 shows the relationship between the effective roll gap and the amount of edge drop improvement obtained in advance with the roll gap reference position being 100 mm from the plate edge. Curve A
7 shows a relationship at a position of 10 mm from the plate edge, and a curve B shows a relationship at a position of 30 mm from the plate edge.
Correspond to the curves C and D shown in FIG.

In the present embodiment, the calculation is executed in the control device 20 by modeling the relationship between these two positions as a model expression as follows.

ΔE10 = 0.004 × ΔS10 ² (19) ΔE30 = 0.003 × ΔS30 ² (20) where ΔE10: the amount of edge drop improvement at a position 10 mm from the plate edge ΔS10: a position 10 mm from the plate end E30: Effective roll gap at 30 mm from the plate edge ΔS30: Effective roll gap at 30 mm from the plate edge

The effect when the above-mentioned steel sheet is actually rolled using the above-mentioned rolling equipment will be described with reference to FIG.

First, a comparative example will be described. In FIG. 13, a polygonal line indicated by a symbol A indicates a thickness profile at a plate edge when the steel plate is rolled with a flat work roll having no taper estimated from the base plate thickness profile. The broken line B indicates the thickness profile when the same steel sheet was rolled by a conventional single taper work roll, and the broken line B is the result of rolling by a single taper work roll shift with a shift amount of 40 mm. .

According to the results shown in FIG. 13, the broken line A does not reach the target over the entire position from the plate end to the position 50 mm, whereas the broken line B improves the target edge drop at the position 30 mm from the plate end. Can do
At a position 10 mm from the edge of the sheet, the thickness was increased by 10 μm or more, and in any case, the sheet could not be rolled to a uniform thickness over the entire width direction.

Next, the results of applying the edge drop control method according to the present invention to the same steel plate will be described.

Assuming that the edge drop amount when the flat work roll is rolled at a position 10 mm (x1) from the plate edge is E10, E10 = -27 μm from the broken line A in FIG. Therefore, the required edge drop improvement amount ΔE10 required to improve the target edge drop is ΔE10 = 0 − (− 27) = 27 μm.

The effective roll gap ΔS10 required to obtain the edge drop improvement amount ΔE10 is obtained from the relational expression between the effective roll gap and the edge drop improvement amount at a position 10 mm from the plate edge shown in the above equation (7). ΔS10 = ｛(ΔE10 / 0.004)｝ ^1/2 ≒ 82 μm.

Although the details are omitted, 30 mm from the plate edge
When the effective roll gap is obtained at the position (x2) in the same procedure, ΔS30 ≒ 37 μm.

By substituting the above values into the above equations (1) and (2), the shift amount EL and the cross angle θ are respectively EL = 20 mm θ = 0.8 °. The shift amount and the cross angle to be set can be calculated.

As described above, the first stand control device 20
Are output to the shift operating device 12 and the cross operating device 14, respectively, and the work roll of the same stand is moved to the shift operating device 12
Is set to the shift amount, and the cross operation device 14 is set to the cross angle.

Thereafter, by performing rolling under the set conditions, a plate-thickness pro film indicated by the broken line C in FIG. 11 was obtained. As can be seen from the broken line C, in the present embodiment, the edge drop could be improved to the target range by the setting control.

As described above, according to the present embodiment as well, it is possible to improve the edge drop which cannot be achieved by the conventional single taper WR shift rolling or simple cross rolling, and the uniformity can be obtained over the entire width direction. It has become possible to obtain a good plate profile.

Next, a second embodiment according to claims 1, 3 (4) and 5 will be described in detail.

FIG. 14 is a side view including a block diagram showing a schematic configuration of a cold tandem rolling mill (rolling equipment) applied to the present embodiment.

The rolling equipment applied to this embodiment is a four-high rolling mill in which the shift cross rolling mill of the first stand is composed of a work roll and a backup roll, as in the case of the first embodiment. Each of the rolls 10 is provided with a taper at one end in the axial direction at a point symmetrical position, and these upper and lower work rolls 10 are supported by backup rolls from above and below, respectively, and the upper and lower work rolls 10 cross each other, and Is to be shifted. The work roll diameter of the first stand was 570 mm, and the taper amount (taper slope) was 1 /.
400.

That is, in the tandem rolling mill, the first
As in the case of the embodiment, a shift operating device 12 for shifting the upper and lower work rolls 10 to a predetermined position, a cross operating device 14 for crossing the upper and lower work rolls at a predetermined angle, and a plate on a rolling mill exit side (final stand exit side). Thickness profile target value setting device 18 for setting a target value of thickness profile
And a first stand control device 20 that outputs control signals to the shift operation device 12 and the cross operation device 14.

In the present embodiment, a thickness profile measuring device 22 is provided on the exit side of the rolling mill, and information on the thickness profile after the rolling of the material to be rolled measured by the measuring device 22 (actually measured edge drop amount). And the change amount of the shift position and the cross angle of the first stand are calculated based on the target value (target edge drop amount) of the thickness profile set by the thickness profile target setting device 18, The work roll 10 is output to the operation device 12 and the cross operation device 14 to adjust the work roll 10 to a predetermined shift position and a predetermined cross angle.

In the control device 20, the change amount of the edge drop with respect to the change amount of the effective roll gap is held in advance as the influence coefficient K, and the deviation between the edge drop amount measured at the exit side of the rolling mill and the target edge drop amount is calculated. It is calculated as a required edge drop improvement amount, and the roll gap change amount required for the edge drop improvement is obtained by multiplying the improvement amount by the reciprocal of the influence coefficient.

Then, the shift position change amount and the cross angle change amount which can obtain the necessary roll gap change amount are calculated by the equations (17) and (18), respectively. The feedback control is performed by changing and adjusting the shift position and the cross angle of the upper and lower work rolls 10 of one stand.

Next, the operation of the present embodiment will be described.

The material to be rolled was 920 m wide, pickled after rolling.
m for tin plate, and the edge drop control points are two points of 10 mm position (x1 point) and 30 mm position (x2 point) from the edge of the plate. The target allowable range of the edge drop amount at each of these control points is 0 to 0. -2 μm. FIG. 15 shows the influence coefficient at each position from the plate edge obtained in advance for this tin plate steel plate. In FIG. 15, the effective roll gap reference position is a position 100 mm from the plate edge.

The effect when the above steel sheet is actually rolled using the rolling equipment shown in FIG. 14 will be described with reference to FIG.

First, a comparative example will be described. This figure 1
In FIG. 6, the polygonal line indicated by the symbol A indicates the thickness profile near the end of the sheet measured on the exit side of the rolling mill during rolling.
The plate profile A is a result obtained by rolling the work roll shift cross rolling mill of the first stand at a cross angle of 0 ° and a shift position of 42 mm. In the thickness profile of A, the edge drop falls within the target allowable range at the position of 10 mm from the edge of the plate, but becomes excessively thick at the position of 30 mm from the edge of the plate, and can be rolled into a uniform thickness over the entire width direction. Not.

The thickness profile of the above-mentioned steel plate when the conventional one-side tapered work roll shift rolling in which the shift position is 43 mm at the first stand is indicated by reference numeral B in FIG. In the case of this single taper work roll shift rolling,
At the position 30 mm from the plate edge, the target edge drop can be improved, but at the position 10 mm from the plate edge, the edge drop amount is smaller than -2 μm, and as a result, a uniform plate thickness cannot be obtained over the entire width direction. Was.

Next, the result of applying the edge drop control method according to the present invention to the same steel plate will be described.

Assuming that the edge drop amount measured on the exit side of the rolling mill during rolling at a position 30 mm from the plate edge is ED30, the plate profile of the broken line A shown in FIG. 16 is improved to the target edge drop (= 0 μm). The required amount of edge drop improvement ΔED30 required for this is ΔED30 ≒ −0.7 μm.

The effective roll gap ΔSb30 required to obtain the edge drop improvement amount ΔED30 is the effective roll gap change amount, the edge drop improvement amount, and the influence coefficient at a position 30 mm from the plate end shown in the above equation (14). From the relational expression, ΔSb30 = ΔED30 / K30 ≒ −11 μm.

At the position 10 mm from the edge of the plate, since the broken line A is within the target range, there is no need to change the effective roll gap, so that ΔS10 ≒ 0 μm.

By substituting the above values into the above-mentioned equations (17) and (18), ΔEL = −16 mm Δθ = 0.7 °, which is set in the case of the rolling in which the thickness profile of the symbol A is obtained. Then, the change amount from the shift position EL (= 42 mm) and the cross angle θ (= 0 °) is calculated.

Thereafter, the work roll 10 of the first stand
Is changed by the shift position change amount and the cross angle change amount, and rolling is performed. As shown by the thickness profile of the broken line indicated by the reference numeral C in FIG. It could be improved within the range.

As described above, according to this embodiment, feedback control is performed based on the thickness profile (edge drop amount) actually measured on the exit side of the rolling mill.
It has become possible to improve the edge drop with high precision, which was impossible in the past, and as a result, it has become possible to obtain a uniform plate profile over the entire width direction.

Although the present invention has been specifically described above, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof.

For example, as described above, the roll gap reference position for calculating the effective roll gap is not limited to the case where it is set to a position 100 mm from the end of the sheet, but the sheet thickness, deformation resistance, An optimum value can be obtained according to various conditions such as a work roll diameter and a rolling load.
Therefore, the present invention can be widely applied without being restricted by these conditions.

Further, the relationship between the effective roll gap and the edge drop improvement amount is not limited to the model formula using the quadratic function as shown in the above-described embodiment, but may be any one such as a model formula using another function or a table formula. May be represented by the following method.

The number of control points is not limited to two.
Three or more points may be used.

Further, the specific configuration of the rolling equipment applicable to the present invention is not limited to the one described in the above embodiment. For example, the rolling mill is not limited to the four-high rolling mill, but may be a six-high rolling mill or a two-high rolling mill. The number of stands is not limited to the six-stand described in the embodiment, but may be a four-stand, five-stand, or single-stand. Is optional.

The stand provided with the shift cross mechanism for the tapered work roll is not limited to the first stand, but may be any stand. You may.

The work roll is not limited to a single cross roll, but may be a pair cross rolling mill that crosses a pair with a backup roll.

Further, the taper of the work roll may be provided at both ends of the roll, and the shape thereof may be not only a simple slope but also a sin curve or a shape having a plurality of slopes. .

The plate material to be rolled is not limited to a steel plate, but may be another metal plate such as an aluminum plate or a copper plate.

[0133]

As described above, according to the present invention,
Edge drop, which is a sudden decrease in the thickness of the sheet material at both ends in the width direction, can be surely reduced, and the sheet material can be rolled to a uniform thickness throughout the width direction.

[Brief description of the drawings]

FIG. 1 is a front view conceptually showing a work roll.

FIG. 2 is an explanatory diagram showing a relationship between a shift position of a work roll and a plate material.

FIG. 3 is a plan view showing a cross angle of a work roll.

FIG. 4 is an explanatory diagram conceptually showing a roll gap change amount based on a conventional standard.

FIG. 5 is an explanatory view conceptually showing an effective roll gap change amount employed in the present invention.

FIG. 6 is a diagram showing a relationship between an effective roll gap and an edge drop improvement amount.

FIG. 7 is a diagram showing a relationship between an effective roll gap change amount and an edge drop change amount.

FIG. 8 is a diagram showing a relationship between an effective roll gap and an edge drop improvement amount at two control points.

FIG. 9 is a flowchart showing a procedure for executing the edge drop control method of the present invention.

FIG. 10 is a diagram showing the relationship between the measured thickness profile on the exit side of the rolling mill and the required edge drop improvement amount.

FIG. 11 is an explanatory diagram showing a schematic configuration of a rolling facility applied to the first embodiment according to the present invention.

FIG. 12 is a diagram illustrating a relationship between an effective roll gap and an edge drop improvement amount in the first embodiment.

FIG. 13 is a diagram showing an effect of improving edge drop according to the first embodiment;

FIG. 14 is an explanatory diagram showing a schematic configuration of a rolling facility applied to the second embodiment.

FIG. 15 is a diagram showing an influence coefficient at each distance from a plate edge.

FIG. 16 is a diagram showing effects of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Work roll 12 ... Shift operation device 14 ... Cross operation device 16 ... Base plate profile detection device 18 ... Sheet thickness profile target value setting device 20 ... Control device 22 ... Sheet thickness profile measurement device

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuo Yarida 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel (72) Inventor Toshihiro Fukaya 1-1-1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba (72) Inventor Tomohiro Kaneko 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Chiba Works Chiba Works

Claims (5)

[Claims] The present invention relates to a method of rolling a work roll having a mechanism for axially shifting a work roll having at least one tapered end on one side and a mechanism for crossing a pair of upper and lower work rolls. An edge drop control method in sheet rolling, wherein a roll gap reference position is set at a position separated by a predetermined distance from a plate edge, and an upper and lower work roll interval based on the reference position is defined as an effective roll gap. An edge drop control method in sheet rolling, wherein a relationship with an edge drop correction amount is determined in advance, and rolling is performed by setting or adjusting a shift position and a cross angle of the work roll based on the relationship. 2. The effective roll according to claim 1, wherein an amount of edge drop to be corrected is determined from an actual measurement plate profile on the entry side of the rolling mill and a target edge drop amount after rolling. Applying the relationship between the gap and the edge drop correction amount, calculate the effective roll gap amount required to correct the edge drop amount to be corrected, and calculate the shift position and the cross angle that satisfy the effective roll gap amount. An edge drop control method in sheet rolling, wherein upper and lower work rolls are set at the shift position and the cross angle and rolling is performed. 3. The method according to claim 1, wherein a deviation between an actually measured edge drop amount measured on the exit side of the rolling mill at the time of rolling and a target edge drop amount after rolling is obtained. By applying the relationship, the effective roll gap change amount required to eliminate the deviation is calculated, and the shift position change amount and the cross angle change amount necessary to obtain the required effective roll gap change amount are obtained. An edge drop control method in plate rolling, wherein rolling is performed by adjusting a shift position and a cross angle of a work roll. 4. The rolling device according to claim 1, wherein the work roll shift position and the cross angle are set to predetermined values, respectively, and rolling is performed, and an actual measured edge drop amount measured at a rolling mill exit side during rolling and a target edge after rolling. A deviation from the drop amount is obtained, and the relationship between the effective roll gap and the edge drop correction amount is applied to the deviation to calculate an effective roll gap change amount necessary to eliminate the deviation. An edge drop control method in plate rolling, wherein a shift position change amount and a cross angle change amount necessary for obtaining a change amount are obtained, and the work roll shift position and the cross angle are adjusted to perform rolling. 5. The method according to claim 1, wherein at least two points for controlling the edge drop amount are provided on one side in the sheet width direction.