JPH1157821A - Intermediate roll of rolling and rolling shape control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method, wherein compound elongation of the plate width quarter part can be corrected to the simple elongation shape, and also a flat shape steel plate can be rolled with the combined use of the work roll bender by giving the axial direction profile comprising the multi-dimensional curve not less than quintic dimension to the intermediate roll of the six stage HC mill, and changing the profile corresponding to the shape of the rolled material of the rolling mill exit side. SOLUTION: The multi-dimensional curve profile of the quintic or higher dimension which becomes the point symmetry at the upper and lower intermediate rolls is given to a quintic curve portion 40B except for a drum section shaft edge taper portion 40A of the intermediate roll 40. In the rolling, the shift position of the intermediate roll 40 is preset in accordance with the place width of the rolled material 8, and the shift control is carried out corresponding to the detected value of the detector of the rolled material shape of the rolling mill exit side. By this, the gap between rolls can be controlled as a quartic function, and the rolled material shape is made to be the simple elongation. The difference of the elongation rate can be can be reduced by feeding back the measurement result of elongation rate difference of the width direction of the rolled material, and by optimizing the bender of the work roll 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate roll of a rolling mill and a rolling shape control method using the same, and more particularly, to a method suitable for use in a 6-stage HC (high crown) mill.
The present invention relates to an intermediate roll of a rolling mill capable of controlling local elongation of a sheet width quarter section, and a rolling shape control method using the same.

[0002]

2. Description of the Related Art In recent years, in a cold sheet rolling, as a rolling mill for rolling a thin material or a hard material, as shown in FIG. A six-stage HC mill 10 in which an intermediate roll 14 having a tapered portion 14A formed at one end in the axial direction is arranged in the middle of a supporting roll 16 to be used has been used.

When controlling the shape of the rolled material 8 by such a six-stage HC mill 10, as shown in FIG.
A roll bender that bends both ends of the work roll 12 and the intermediate roll 14 (work roll bender 20 in FIG. 12);
Press leveling 2 to adjust the level of the left and right rolls
2. Roll shift of the work roll 12 and the intermediate roll 14 in the axial direction (intermediate roll shift 24 in FIG. 12), control of the coolant for cooling the rolled material 8 at the exit side of the mill 10 (zone coolant 26 or spot coolant 28)
And the like, and the result of determination by the shape determiner 32 based on the difference in the elongation percentage in the width direction of the rolled material 8 detected by the shape detector 30 installed on the exit side of the mill 10, or the shape determination by visual inspection According to the result, control using an appropriate actuator is performed corresponding to each elongation component. For example, the primary function component of the shape determination result is controlled by the reduction leveling 22, the quadratic function component is controlled by the work roll bender 20, and the local elongation is determined by the roll width direction of the spot coolant 28 (the roll axis direction). ) Controlled by injection position. The zone coolant 26 and the intermediate roll shift 24 are controlled by an initialization model 34. In the figure, reference numeral 18 denotes a winding machine for winding the rolled material 8 after rolling.

As described above, in the conventional HC mill,
The asymmetrical primary and symmetrical secondary shape defects can be corrected by the pressing down leveling 22, the work roll bender 20, and the intermediate roll shift 24, respectively. On the other hand, the local elongation and the composite elongation of the plate width quarter are coped with by controlling the coolant such as the spot coolant 28 and the zone coolant 26.

[0005]

However, since the coolant control has poor responsiveness, there is a problem that sufficient ability to correct local elongation or composite elongation of the rolled material cannot be obtained by itself.

On the other hand, as an attempt to improve the shape quality of the rolled material 8 by attaching an initial crown to a rolling roll such as a work roll or an intermediate roll, Japanese Patent Application Laid-Open No. 62-263805 discloses
A method has been proposed in which an S-shaped initial crown of a cubic function curve is given to the work roll to prevent the occurrence of composite elongation in the quarter (1/4) width of the plate. It is described that an S-shaped initial crown having a cubic curve is imparted to the intermediate roll and the intermediate roll.
It is described that the intermediate roll has a sine-wave initial crown for two cycles. Japanese Patent Laid-Open No. 13218/1991 describes that both the work roll and the intermediate roll have an initial crown of a cubic curve or a quintic curve, and an initial crown of two cycles. It is described to have a sinusoidal initial crown.

[0007] However, attempts to attach an initial crown to these rolls have not been sufficiently effective.

Further, it has been proposed to provide a bender not only for the work roll 12 but also for the intermediate roll 14 to control the local elongation of the sheet width quota section in combination with the work roll bender 20. Necessary remodeling,
In order to increase the cost, it has been difficult to apply it to an existing HC mill having no intermediate roll bender function.

The present invention has been made in order to solve the above-mentioned conventional problems. Even in an HC mill having no intermediate roll bender function, correction of local elongation and composite elongation can be achieved only by changing the profile of the intermediate roll. The task is to improve the ability.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a taper is formed at an axial end, and a work roll and a support roll are provided between the work roll and the support roll.
In an intermediate roll of a rolling mill arranged so as to be shiftable in the axial direction, a portion other than the taper, an axial roll formed of a quintic or higher-order multi-dimensional curve which is point-symmetric with upper and lower intermediate rolls. By giving a profile and changing the roll gap by shifting in the axial direction,
This has solved the above-mentioned problem.

Further, the axial shift position of the intermediate roll is
By presetting according to the strip width of the rolled material and correcting according to the shape of the rolled material on the exit side of the rolling mill, the local elongation of the strip width quarter section is controlled, and the above-mentioned problem is also solved. .

In order to control the quarter elongation, which is a problem particularly in wide-width cold-rolled steel sheets, the inventors of the present invention have applied an intermediate roll with an initial crown of a fifth order or higher to shift it in the axial direction. The effect of the shape on the plate shape was investigated.

Since the quarter elongation is controlled, it is necessary to give a higher-order curve of the fifth order or higher. First, the case where the shape of the intermediate roll is a fifth-order formula of the axial position as shown in FIG. 1 was studied. . The coordinate normalized by the barrel length of the work roll is x (-1 ≦ x ≦ 1), the shift amount of the upper roll normalized by half the barrel length of the work roll is Su, and the barrel of the work roll is also Assuming that the shift amount of the lower roll normalized by half the length is SL, and that the rightward movement in FIG. 1 is positive, the lower roll shape yU of the upper roll, the upper roll shape yL of the lower roll, and the roll gap shape g is represented by the following equations (1), (2), and (3), respectively.

YU (x) = a0 + a1 (x-SU) + a2 (x-SU) ² + a3 (x-SU) ³ + a4 (x-SU) ⁴ + a5 (x-SU) ⁵ ... (1) -yL ( x) =-b0 + b1 (-x + SL) + b2 (-x + SL) ² + b3 (-x + SL) ³ + b4 (-x + SL) ⁴ + b5 (-x + SL) ⁵ ... (2) g (x) = yU (x) -yL ( x)… (3)

Here, ai and bi are constants.

Now, using the condition that the upper roll lower surface shape yU and the lower roll upper surface shape yL are point symmetric, ai = b
If i≡ci (i = 0-5) and SU = −SL≡S,
The roll gap shape g (x) is represented by the following equation.

G (x) = C 0 + C 1 (x−S) + C 2 (x−S) ² + C 3 (x−S) ³ + C 4 (x−S) ⁴ + C 5 (x−S) ⁵ + C 0 + C 1 (−x−S ) + C2 (-x-S) ² + C3 (-x-S) ³ + C4 (-x-S) ⁴ + C5 (-x-S) ⁵ ... (4)

When the equation (4) is arranged for coordinates x, the following equation is obtained.

[0019] g (x) = (2C0 -2C1 S + 2C2 S 2 -2C3 S 3 + 2C4 S 4 -2C5 S 5) + (2C2 -6C3 S + 12C4 S 2 -20C5 S 3) x 2 + (2C4 -10C5 S) x ⁴ … (5)

Here, the first term on the right side of the equation (5) is a zero-order term,
The second term is a second-order term, the third term is a fourth-order term, and the zero-order term can be corrected by rolling leveling, and the second-order term can be corrected by a work roll bender. Therefore, the fourth-order term is a term for controlling the quarter unit.

As long as the point symmetry condition can be applied, the roll gap shape g (x) is left-right symmetric, and only the even-numbered term of the coordinate x remains. Here, the extreme value of g (x) is g ′ (x)
From = 0, the following equation is obtained (see FIG. 2).

[0022] x = 0 ... (6) x0 = 5√ {(C2 -3C3 S + 6C6 S 2 -10C5 S 3) / - (2C4 -10C5 S)} ... (7)

That is, the position of the extremum changes with the second-order or higher-order coefficient and the shift position of the roll curve. Therefore, the local extension of the quarter unit can be controlled by making the extremum come to the quarter unit and changing the position of the extremum.

It is to be noted that a curve of fourth order or less has only a third-order term in the roll gap shape g (x), and is not suitable for controlling the quarter section. In particular, if it is a cubic curve,
Since the roll gap shape is a quadratic curve, it can be controlled by a roll bender and is meaningless.

When the order of the higher-order curve is odd, the roll gap shape is even and the shape is left-right symmetric, so that the left and right sides can be controlled simultaneously.

On the other hand, if the order of the higher-order curve is an even order,
Since the roll gap shape is odd-order, the roll gap becomes asymmetrical and the control becomes complicated. However, it is possible to perform left and right separate quota control.

FIG. 3 shows an example of the roll profile of the upper and lower intermediate rolls when a fifth-order curve is given to the intermediate roll, and FIG. 4 shows the change of the roll gap profile during the roll shift at that time.

As described above, by providing the upper and lower intermediate rolls with a slight initial crown having a curve of fifth order or higher so as to be symmetrical with respect to the point, as shown in FIG. The roll gap in the part is widened, preventing the occurrence of quarter expansion, and the intermediate roll shift changes the roll gap of the quarter part, thereby making it possible to control the quarter expansion with high response.

The shift position of the intermediate roll can be preset according to, for example, the sheet width, and can be corrected according to the performance of the shape detector on the mill exit side.

At this time, the shift and bender conditions do not need to be changed much from the conventional operation.

[0031]

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

In the first embodiment of the present invention, as shown in FIG. 5, in a 6-stage HC mill similar to the conventional example, an axis consisting of a quintic curve which is point-symmetric with the upper and lower intermediate rolls is provided on a portion 40B other than the taper. It incorporates an intermediate roll 40 provided with a directional roll profile. The other points are the same as in the conventional example, and the description is omitted.

The amount of crown in the axial direction of the intermediate roll 40 is 50 to 2000 in consideration of shape controllability and operability.
It can be in the range of μm.

The shift position of the intermediate roll 40 is preset according to the sheet width of the rolled material 8 and is controlled according to the performance of the shape detector 30 on the mill exit side.

In this embodiment, the fifth-order curved portion 40B
Since the tapered portion 40A is provided on the hill side of
The fifth order curve and the taper are smoothly connected, and processing (polishing) of the intermediate roll with a grindstone or the like is easy.

The relationship between the quintic curve and the taper is the first.
The present invention is not limited to the embodiment, and a tapered portion 40A may be provided on the flat side of the fifth-order curved portion 40B as in the second embodiment shown in FIG.

[0037]

FIGS. 7 to 9 show a case where a conventional flat intermediate roll 14 is used (FIG. 7) and a case where a fifth order curved intermediate roll 40 is used according to the present invention (FIG. 8). The difference in the elongation percentage in the width direction of the rolled material in 9) is shown for each sheet width in comparison.

In the experiment, the thickness of the mother plate was 3.2 mm / the thickness of the product was 0.2 mm.
70 mm, 800-1600 mm in plate width, and the initial crown of the intermediate roll has a maximum amplitude of 200 μm.
Was used. Other experimental conditions are as shown in FIG.

Under the conventional conditions, quarter elongation occurs irrespective of the sheet width, and the difference in elongation ratio in the width direction tends to increase as the width increases. On the other hand, in the case of the present invention, the gap between the rolls can be controlled as a quartic function by imparting a quintic curve shape to the intermediate roll, so that as shown in FIG. It can be changed from quarter extension to simple antinode extension (symmetric quadratic component).
Further, by feeding back the data obtained by measuring the difference in the elongation in the width direction of the rolled material and optimizing the work roll (WR) bender, the difference in the elongation in the width direction is reduced to 1/3 or less of the conventional one as shown in FIG. Good result that the level can be reduced to the level of

[0040]

According to the present invention, it is possible to correct the composite elongation shape in the quarter width section to a simple belly elongation shape only by changing the profile of the intermediate roll without using an expensive intermediate roll bender. A flat shape can be obtained in combination with a roll bender. Therefore, the equipment modification of adding an intermediate roll bender is unnecessary,
It can be implemented relatively inexpensively.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a relationship between a profile of upper and lower rolls and a shape of a roll gap for explaining the principle of the present invention.

FIG. 2 is a diagram showing extreme values of a roll gap shape.

FIG. 3 is a diagram showing an example of a profile of an intermediate roll given a fifth-order curve according to the present invention;

4 is a diagram showing an example of a change state of a gap between rolls when the intermediate roll in FIG. 3 is shifted.

FIG. 5 is a front view showing a configuration of a six-stage HC mill into which the first embodiment of the intermediate roll according to the present invention is incorporated.

FIG. 6 is a front view showing the shape of a second embodiment of an intermediate roll.

FIG. 7 is a diagram showing an example of a difference in elongation percentage in the width direction of a rolled material in a conventional example.

FIG. 8 is a diagram showing an example of a difference in elongation percentage in the width direction of a rolled material before optimizing a work roll bender in an embodiment of the present invention.

FIG. 9 is a diagram showing an example of a difference in elongation percentage in the width direction of a rolled material after work roll bender optimization.

FIG. 10 is a table showing experimental conditions when obtaining the data of FIGS. 7 to 9;

FIG. 11 is a front view showing a configuration example of a conventional 6-stage HC mill incorporating an intermediate roll.

FIG. 12 is a block diagram showing a configuration of a shape control system of a six-stage HC mill.

[Explanation of symbols]

 8 ... Rolled material 10 ... Mill 12 ... Work roll 14, 40 ... Intermediate roll 14A, 40A ... Tapered portion 16 ... Support roll 24 ... Intermediate roll shift 30 ... Shape detector 40B ... 5th order curved portion

Claims (2)

[Claims] 1. An intermediate roll of a rolling mill having a taper formed at an axial end portion and arranged between a work roll and a support roll so as to be shiftable in an axial direction. Rolling characterized by imparting an axial roll profile consisting of a quintic or higher order curve that is point symmetrical with the upper and lower intermediate rolls, and the roll gap is variable by shifting in the axial direction. Middle roll of machine. 2. The sheet width quarter by presetting the axial shift position of the intermediate roll according to claim 1 according to the sheet width of the rolled material and correcting it in accordance with the shape of the rolled material on the exit side of the rolling mill. Controlling a local elongation of a portion, wherein the rolling shape is controlled using the intermediate roll.