JP3244119B2 - Strip shape and edge drop control method in strip rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a sheet shape and an edge drop in sheet rolling, and more particularly to a method for controlling a sheet shape suitable for rolling a sheet material such as a steel sheet in a cold rolling mill. The shape and shape of a sheet in rolling can be improved by improving the sharp thickness reduction at both ends in the width direction, called edge drop, and making the thickness distribution in the width direction almost uniform throughout. The present invention relates to an edge drop control method.

[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 plate rolling, it is necessary to reduce the edge drop in order to make the thickness distribution in the width direction uniform and obtain a good material to be rolled.

[0003] As a control method for reducing the edge drop generated in such a sheet material, a rolling method for shifting a work roll (WR) having a tapered end on one side in the roll axis direction has conventionally been used. ing.

For example, in Japanese Patent Publication No. 2-34241, a work roll having a tapered end on one side is used, shifted in the roll axis direction, and the thickness profile of the base plate on the entry side of the rolling mill ( The thickness profile on the exit side of the rolling mill is estimated from the width distribution in the width direction), 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. A method is disclosed in which a work roll is shifted to a position where the difference between the two is minimized by comparing the thickness with a thickness profile.

In Japanese Patent Application Laid-Open No. Sho 60-12213, in order to prevent the plate shape from deteriorating when shifting the tapered work roll and controlling the edge drop, the roll bender control is performed together with the shift control. Performing techniques are disclosed.

[0006] Also, a document "Sheet Crown / Edge Drop Control Characteristics" (Preprints of the 45th Lecture Meeting on Plastic Working, 403
-406 page, 1994), the upper and lower work rolls,
By crossing with the backup roll on each side, a parabolic roll gap generated from the center in the width direction between the upper and lower work rolls toward the plate edge,
It is disclosed that there is an effect of making the thickness 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. Sho 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 point). 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 change significantly at the coil welding point, in order to maintain a good plate shape, in the transition state of the roll cross angle setting from the start of the roll cross angle setting change to the end of the change, While changing the shift amount of the work roll, the work roll angle and the work with respect to the succeeding coil are determined from the roll cross angle and the work roll bend force that are set from the optimum curves indicating the relationship between the roll cross angle and the work roll bend force with respect to the preceding coil. The work roll bend force is changed according to the optimum pattern so that the roll bend force can be changed in the shortest time, and only a part of the coil is handled.

[0009]

However, in the technique disclosed in Japanese Patent Publication No. 2-32411, the taper of the work roll is applied to the roll by polishing before rolling, and the taper during the rolling is used as it is. It is impossible to change the amount, shape, etc. Usually, the work roll is not replaced for each rolled material, but is used for rolling several tens of rolls. Therefore, in rolling several tens of rolled materials, if the edge drop of the mother plate is large, the edge drop improvement is insufficient, or if the edge drop of the mother plate is small, the edge drop improvement becomes excessive. In addition, problems such as an excessively thick plate edge occur. Further, as an edge drop control method, the present technology only discloses a method of setting only a shift position based on a transfer rate, and does not disclose a control method when a cross is combined, for example. If shift control is performed such that the tapered portion of the work roll enters the sheet path through which the material to be rolled actually passes, the load distribution changes significantly, and the sheet shape also changes greatly.

On the other hand, Japanese Patent Application Laid-Open No. Sho 60-12213 discloses that
When shifting a work roll with a taper and controlling edge drop, to prevent the plate shape from deteriorating, the technology that controls the roll bender together with the shift control is disclosed. The plate shape is
It is only a simple secondary component called so-called ear elongation or middle elongation, and it is impossible to control a complicated plate shape that is generated due to the tapered work roll at the end of the plate.

In the method disclosed in the above-mentioned document "Sheet Crown / 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 (plate crown), the effect of reducing edge drop, which is a plate thickness deviation only at the end of the plate width, is small. Further, in the present technology, only the edge drop control method using only the cloth is disclosed, and for example, no control method when a work roll shift is combined is disclosed at all. Due to the resulting parabolic roll gap, measures to prevent the deterioration of the plate shape that occurs when the plate thickness profile is improved,
Nothing is disclosed.

[0012] Also, the Japanese Open Sho 57-206503 is intended to work roll uneven wear prevention is not possible to control the edge drop directly.

[0013] Also, the method described in the Japanese opened flat 5-185125 is intended to prevent the deterioration of the plate-shape in the transition period of the cross angle change, the edge drop is KOKOKU 2-4364, etc. Disclosed in the
It is not possible to expect an improvement effect more than that of the prior art, in which only work roll shift is performed over the entire length of the coil. or,
The edge drop control method using a combination of a work roll and a cloth has problems such as not being disclosed at all.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to surely reduce the edge drop without deteriorating the shape of the plate during rolling and to obtain a uniform plate thickness over the entire width direction. Rolling to

[0015]

SUMMARY OF THE INVENTION The present invention provides a mechanism for axially shifting a work roll having a tapered end on one side of the roll, and a rolling mill provided with a mechanism for crossing the work roll. In edge drop control,
A system for obtaining a desired edge drop improvement based on the relationship between the cross angle and the shift amount and the edge drop improvement effect.
The shift amount and the range of the cross angle are calculated, and the shift to the optimum shape is performed based on the relationship between the cross angle and the shift amount and the plate shape.
Select the shift amount and cross angle, and operate the shift amount and cross angle.
The object has been solved by controlling both the edge drop and the plate shape as the work amount .

[0016] Further, the relation between the cross angle and the shift amount and the edge drop improvement, expressed as a relation of the effective roll gap and the edge drop improvement amount relative to the predetermined distance away from the plate end portion, and the Effective roll gear
Gap, cross gap and shift gap
Is obtained by adding .

[0017]

The relationship between the cross angle and the shift amount and the plate shape is defined by a shape plane in which one axis corresponds to the extent of the middle extension / ear extension and the other axis corresponds to the extent of the quarter extension. It is shown.

Further, an edge drop improvement amount is obtained as a difference between the actual edge drop amount and the target edge drop amount, and a range of a cross angle and a shift amount which give the obtained edge drop improvement amount is obtained. A shape plane corresponding to the range of the amount is obtained, an optimum shape is selected within the obtained shape plane, and a cross angle and a shift amount at that time are obtained and used for control.

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

As shown in FIG. 1, the shift is performed by shifting the upper and lower work rolls 1 conceptually.
The operation of moving the work rolls 12 and 14 having tapered ends 16 at one end of the roll ends that are point-symmetrical at points 2 and 14 in the axial direction in the up and down directions, and the shift amount is the amount of movement. More specifically, as shown in FIG. 2 in which the vicinity of one end of the upper work roll 12 is enlarged, the distance EL from the plate end of the material to be rolled 10 to the tapered start end 16A. or,
The roll taper amount is defined as H / L in FIG.

Further, as shown in FIG. 3, the work rolls when the rolling mill is viewed from above are conceptually shown in FIG.
The cross angle θ is の of the angle between the axes of the work rolls 12 and 14.

The inventors of the present invention carried out rolling using a work roll having a tapered end, shifting by crossing a predetermined amount of upper and lower work rolls, and rolling using both work roll shift and cloth. There line, a result of intensive studies, the relationship between the shift amount and the cross angle and the edge drop improvement is grasped to be expressed as follows, for example.

That is, if an effective roll gap reference position is provided at a position separated by a certain distance from the end of the plate, the roll gap based on the reference position (hereinafter referred to as the effective roll gap) can reduce the edge drop improvement amount . It turned out that the relationship could be organized. FIG. 4 shows the results of a rolling experiment.
For example, the relationship between the effective roll gap defined based on the position of the plate edge 100 mm and the edge drop improvement amount is shown. Here, the work roll has a taper amount of 1/30.
Using a roll of 0, the shift amount was changed in a range from 0 to 70 mm, and the cross angle was changed in a range from 0 to 0.8 °.
The evaluation position of the edge drop is defined as the position of the plate end 15 mm, and the thickness deviation from the position of the plate end 100 mm is defined as E15 as follows.

E15 = h15-h100 (1) Here, h15: the thickness at the position of the plate end 15 mm h100: the thickness at the position of the plate end 100 mm

The effect of improving the edge drop is that the shift amount is 0 m.
m and a plate thickness deviation E15 at a position of 15 mm at the end of the roll when rolled with a flat roll having a cross angle of 0 °, and a deviation E15 at a position of 15 mm at the end of the plate when the roll amount and the shift angle are rolled to predetermined amounts. Evaluation was made based on the difference (change amount). From FIG.
When the effective roll gap is small, the edge drop improvement amount is small, but the effective roll gap increases.
One is by, it can be seen that edge drop improvement amount sharply increases.

Although the position of the edge of the plate 15 mm has been described as the evaluation position of the edge drop,
The above-mentioned relationship holds even at other positions, for example, at the position of the plate edge 10 mm or at the position of 20 mm. Also, the effective roll gap reference position may be changed according to various conditions such as the thickness and deformation resistance of the material to be rolled, the roll diameter of the work roll, the rolling load, and the like.
The position is not limited to the 100 mm position described above.

Similarly, from experiments, it was found that the relationship between the shift amount, the cross angle, and the plate shape was expressed as follows.

FIG. 5 shows that the work roll has a taper amount 1 /.
The figure which represented the change of the plate shape at the time of changing the shift amount and cross angle when using 300 rolls was represented by the shape plane. In the figure, # 2 represents a so-called middle stretch shape and ear stretch shape as shown in FIG. 6, and # 4 represents a quarter stretch shape as shown in FIG. 7, and its definition is given by the following equation.

Λ2 = (difference in elongation at plate edge) − (difference in elongation at center of plate width) (2) Λ4 = (difference in elongation at 1 / √2 position from center of width to end of plate) -(Elongation difference at center of plate width) ... (3)

In FIG. 5, in the work roll shift,
Quarter elongation shape # 4 hardly changes, middle elongation / ear elongation shape # 2 changes, and when the shift amount increases, it becomes a medium elongation shape. On the other hand, in the work roll cloth, when the cross angle is increased, both # 2 and # 4 change, and the work roll cloth has a medium elongation shape. Further, when the shift and the cloth are used together, an intermediate shape change between the shift alone and the cloth alone is obtained. As described above, the manner of changing the plate shape differs depending on the change amount of the shift amount and the change amount of the cross angle.

The present invention has been made on the basis of the above two findings, and improved the edge drop while maintaining a good plate shape by rolling using a cloth in combination with the shift of a tapered roll. Things.

[0033]

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

FIG. 8 is a side view including a block diagram showing a schematic configuration of a cold tandem rolling mill (rolling equipment) according to an embodiment of the present invention.

The rolling equipment used in this embodiment is a cold tandem rolling mill consisting of six stands, and the first stand 21 has a tapered end at one end as shown in FIG. Work rolls 12 and 14 are used, and a mechanism for crossing each other is also provided as shown in FIG. The first stand 21 is a four-high rolling mill in which backup rolls 31 for reinforcement are provided above and below the upper and lower work rolls 12 and 14.

The work roll 12 of the first stand 21,
14 is shifted to a predetermined position by the shift cross operation device 40 and crossed at a predetermined angle.

On the exit side of the first stand 21, a shape detector 42 for measuring a plate shape is provided.
On the exit side of the sixth stand, a thickness profile meter 44 for measuring edge drop is provided.

The first stand control device 50 controls the plate shape measured by the shape detector 42, the exit edge drop information measured by the thickness profile meter 44, Edge drop information of the base plate measured at any position up to the entry side of the cold tandem rolling mill, various input of rolling conditions, plate shape target, edge drop target in the cold tandem rolling mill such as plate thickness and load , The shift amount and the cross angle are calculated and output to the shift cross operation device 40, and the work rolls 12, 1
4 is controlled. The first stand control device 50 further includes:
According to the present invention, both the edge drop and the plate shape are controlled based on the relationship between the predetermined cross angle and shift amount and the effect of improving the edge drop, and the relationship between the cross angle and shift amount and the plate shape.

In the present embodiment, the diameter of the work rolls 12 and 14 of the first stand is 570 mm, and the taper amount is 1/3.
As the material to be rolled 10, a tin plate steel sheet having a width of 900 mm, which was pickled after rolling, was rolled. The edge drop control point was located at a position of 15 mm at the edge of the plate, and the target was a thickness deviation of 0 μm at the control point. The effective roll gap reference position was set to a position of 100 mm at the plate edge.

In the present embodiment, the relationship between the cross angle and shift amount and the effect of improving the edge drop is modeled as follows.

ΔE15 = 0.004 × (ΔS15) ² (4) where ΔE15: the amount of improvement in thickness deviation at the position of the plate end 15 mm ΔS15: the effective roll gap at the position of the plate end 15 mm

The effective roll gap ΔS15 is obtained by substituting 15 for x in the following equation (5) from the gap fx 100 (EL) due to the shift and the gap gx 100 due to the cross.

ΔSx = fx100 (EL) + gx100 (θ) (5) where fX100 (EL) = (EL−x) · tanα (6) gx100 (θ) = 2 [｛(W / 2) −x｝ ² + ｛(W / 2) −100｝ ² ] · tan ² θ / (D · W) (7) where EL: shift amount tan α: taper amount θ: cross angle D : Roll diameter W: Sheet width

Further, based on the relationship as shown in FIG. 5, the relationship between the cross angle and the shift amount and the plate shape was modeled as follows.

ΔΛ2 = −3 · ΔEL−300 · Δθ (8) ΔΛ4 = −0.2 · ΔEL−300 · Δθ (9) where ΔΛ2: variation of shape Λ2 , ΔΛ4: shape Λ4
The amount of change, ΔEL: the amount of change in shift amount EL, Δθ: change the amount of the cross angle θ

In the control according to the present invention, first, an edge drop (plate thickness deviation) improvement amount ΔEx is calculated by the following equation.

ΔEx = (actual edge drop) − (target edge drop) (10)

Next, from equations (4) and (5), (1
The range of the cross angle θ and the shift amount EL that give the edge drop improvement amount ΔEx obtained by equation (0) is calculated.

Next, according to the equations (8) and (9), the shape plane (Λ) corresponding to the range of the cross angle θ and the shift amount EL is described.
2, Λ4) is calculated.

Next, an optimum shape is selected in the above-mentioned shape plane, and the cross angle θ and the shift amount EL at that time are back calculated from the equations (8) and (9) and given to the shift cross operation device 40.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the results of a conventional control will be described. FIG. 9 shows a thickness profile when rolling is performed by a work roll shift with a single taper when the reference position is set to 100 mm from the edge of the plate. The shift amount is 35mm
Thus, the edge drop at the position of the plate edge 15 mm is improved, and the target thickness deviation is obtained. As the plate shape at this time, the elongation difference rate distribution measured by a shape detector is shown in FIG.
0 is shown. The plate shape is a quarter elongation, and the maximum difference in elongation is at least 100 arbitrary units (steepness of 2%), which is usually said to easily cause a plate breakage, and the sheet passing property is extremely poor.

Next, the control result according to the present invention will be described. In the work roll shift cross rolling, based on the relationship between the cross angle and the shift amount and the edge drop improving effect, and the relationship between the cross angle, the shift amount, and the plate shape, the shift amount is 30 mm, and the cross angle is 0.5 °. did. FIG.
Indicates the thickness profile at that time. Board edge 15mm
The edge drop is improved at the position, and the target thickness deviation can be obtained. FIG. 12 shows the plate shape after rolling at this time. The plate shape was a moderately elongated shape, the maximum elongation rate difference was not more than 100 arbitrary units (steepness: 2%) or less, and there was no problem with the sheet passing property.

As described above, according to the present invention, it is possible to improve edge drop while maintaining a good plate shape.

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

For example, the reference position of the effective roll gap is not limited to the position of 100 mm at the end of the plate, but may be other optimum values depending on various conditions such as the thickness of the material to be rolled, deformation resistance, work roll diameter, and rolling load. May be determined.

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 in the above embodiment, but may be any one such as a model formula using another function or a table formula. It may be represented by a method.

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 four-stand, five-stand, or a single-stand. Well, optional.

The stand provided with the work roll shift cross mechanism provided with a tapered work roll has a larger thickness.
It is possible to modify the thickness profile from the inside, and to correct the edge drop of the mother board, it is necessary to use the first
It is desirable to equip the stand with a control stand.
If the stand alone does not provide enough control,
It can be added from the third stand and the upstream side.
Also, when controlling the thickness profile as a product,
It is also effective to perform feedback control at the last stand.

In the measurement of the plate shape, the automatic shape detector may not be installed immediately after the stand provided with the shift cross mechanism, but may be measured visually or manually by an operator. Alternatively, the estimation may be performed using a predetermined prediction table or the like. For example, the shape can be predicted by the following equation from the rolling conditions.

Λ2 = K1 + K2 · P + K3 · B + K4 · T + K5 · D (11) Λ4 = L1 + L2 · P + L3 · B + L4 · T + L5 · D (12) where P: load B: bender T: tension D: roll Diameter K1 to K5, L1 to L5: Coefficient

Alternatively, a quadrant may be selected from the shape plane by visual observation of the operator, and θ and EL within that range may be calculated.

The shift cross mechanism may be a pair cross rolling mill that crosses a backup roll and a work roll in pairs.

Further, the taper of the work roll is not limited to a simple linear shape, but may have a sine wave shape or a plurality of inclinations.

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

[0065]

According to the present invention, it is possible to improve the edge drop while maintaining a good plate shape.

[Brief description of the drawings]

FIG. 1 is a front view showing a shift state of a tapered work roll.

FIG. 2 is a diagram for explaining definitions of a taper amount and a shift amount of an end portion of a work roll.

FIG. 3 is a plan view for explaining the definition of a work roll cloth.

FIG. 4 is a diagram illustrating an example of a relationship between an effective roll gap and a change amount of a plate end portion plate thickness deviation for explaining the principle of the present invention.

FIG. 5 is a diagram showing an example of a shape plane;

FIG. 6 is a diagram showing a definition of a middle stretch / ear stretch shape.

FIG. 7 is a diagram showing a definition of a quota extension shape;

FIG. 8 is a front view, partially including a block diagram, showing an embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a thickness profile when rolling is performed by a single taper work roll shift using a conventional method.

FIG. 10 is a diagram showing the sheet shape after rolling by elongation difference rate distribution.

FIG. 11 is a diagram showing an example of a thickness profile in a control embodiment according to the present invention.

FIG. 12 is a diagram showing the shape of a sheet after rolling by elongation difference ratio distribution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Material to be rolled 12, 14 ... Work roll (WR) 16 ... Taper 40 ... Shift cross operation device 42 ... Shape detector 44 ... Thickness profile meter 50 ... First stand control device

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shozo Ogimoto 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Chiba Works of Kawasaki Steel Corporation (72) Inventor Tomohiro Kaneko 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Corporation Chiba Works (56) References JP-A-10-230311 (JP, A) JP-A-10-216814 (JP, A) JP-A-11-57827 (JP, A) JP-A Hei 6 91314 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 37/28 B21B 13/14 B21B 37/42

Claims (4)

(57) [Claims] An edge drop control for a sheet material using a rolling machine provided with a mechanism for axially shifting a work roll having a tapered end on one side of the roll, and a mechanism for crossing the work roll, comprising: A system for obtaining a desired edge drop improvement based on the relationship between the shift amount and the edge drop improvement effect.
Calculate the range of the shift amount and the cross angle, and optimize based on the relationship between the cross angle and the shift amount and the plate shape.
A sheet shape / edge drop control method in sheet rolling , wherein a shift amount and a cross angle to be a shape are selected, and both the edge drop and the plate shape are controlled using the shift amount and the cross angle as operation amounts . 2. The relationship between the cross angle and the shift amount and the edge drop improvement effect according to claim 1, wherein the relationship between the effective roll gap and the edge drop improvement amount with reference to a position at a certain distance from the plate edge. Represented and before
Note that the effective roll gap is
A sheet shape / edge drop control method in sheet rolling, wherein the gap is obtained by adding a gap based on the sheet shape. 3. The relationship between the cross angle and the shift amount and the plate shape according to claim 1, wherein one axis corresponds to the extent of the middle extension / ear extension shape, and the other axis corresponds to the extent of the quarter extension shape. A sheet shape / edge drop control method in sheet rolling, characterized by being represented by a corresponding shape plane. 4. The method according to claim 3, wherein an edge drop improvement amount is obtained as a difference between the actual edge drop amount and the target edge drop amount, and a range of a cross angle and a shift amount that give the obtained edge drop improvement amount is obtained. Sheet shape rolling, wherein a shape plane corresponding to the range of the cross angle and the shift amount obtained is obtained, an optimum shape is selected within the obtained shape plane, and the cross angle and the shift amount at that time are obtained and used for control. Plate shape / edge drop control method