JPH07171608A - Method for controlling roll cross rolling mill - Google Patents

Abstract

PURPOSE:To correct meandering without generating thickness deviation between the right and left of a rolled stock by controlling the meandering of the rolled stock by respectively independently executing angle setting of the cross angles of an upper work roll and lower work roll. CONSTITUTION:On the upstream side of a finishing mill, the meandering amount (off-center amount of the center of a sheet from the center of a mill) of the rolled stock 1 is detected with a width end position detector 14 and data are transmitted to a meandering computing element 16. Upper and lower cross motors 10, 12 are operated so as to correct meandering with the meandering computing element 16 and the cross angles of the upper and lower work rolls 2, 4 are changed. On the downstream side of the finishing mill, the sectional shape of sheet of the rolled stock 1 is measured with a sheet profile gage 18 and signals are transmitted to the meandering computing element 16. The upper and lower cross motors 10, 12 are operated so as to correct a roll gap with the meandering computing element 16. The cross angles of the upper and lower work rolls are shifted and the off-center of the rolled stock 1 and the off-center of the cross point are made to coincide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for a roll cloth rolling mill which controls meandering of rolled material and difference in plate thickness (one gauge).

[0002]

2. Description of the Related Art Generally, a hot rolling mill is provided with a rough rolling mill having a plurality of stands and a finishing rolling mill, and a heated slab is rolled by the rough rolling mill to a thickness of about 30 to 50 mm. After that, it is rolled into a predetermined size by a finish rolling mill.

At this time, a plan view of the rolled material, as shown in FIG. 1, the rolled material 1 has a meandering (camber) α which is a lateral shift, and a sectional view of the rolled material 1 taken along the line II-II. Figure 2
It is known that a one-sided gauge having a cross-sectional shape with a difference in plate thickness on the left and right as shown in FIG.

As a cause of such meandering and one-sided gauge,
The temperature difference in the width direction of the material, the hardness difference, the plate thickness difference in the raw material slab, and of course, the difference in the roll gap caused by the mill constant difference on the working side and the driving side of the rolling mill at the stage of the rough rolling mill, etc. Can be mentioned.

Further, the so-called off-center, in which the center of the plate of the rolled material deviates from the center of the roll and enters into the rolling mill, causes a difference in roll gap between the working side and the driving side of the roll, resulting in one gauge or meandering. It has been known.

For example, FIG. 3 is a plan view of the rolled material passing through the rolls. In FIG. 3, when the roll gap on the right side is wider than that on the left side, the peripheral speed of the roll 2 is even on the left and right sides. Regardless, since the roll gap on the right side is wide, the volumetric flow rate of the rolled material 1 per unit time is larger on the right side. Further, if the thickness of the rolled material 1 on the inlet side is symmetrical, the rolled material 1 is pulled in faster on the side of a larger volume flow rate.

As a result, as shown by the chain double-dashed line in FIG.
The rolled material 1 approaches the right side by Δx on the entrance side, and a camber α occurs on the exit side. Therefore, the difference between the roll gaps on the left and right is further increased, the rolled material 1 approaches the right end more rapidly, and the meandering phenomenon occurs.

The meandering can be roughly divided into those generated in the rough rolling mill and those generated by the finishing rolling mill group.
It goes without saying that the meandering generated in the finishing rolling mill group is particularly affected by the meandering or the single gauge formed by the rough rolling mill.

As a method for controlling the meandering of the rolling mill generated by the rough rolling mill in the finishing rolling mill group, Japanese Patent Laid-Open Publication No. 6-58242
As disclosed in JP-A 2-54511, there is a method in which a strip edge detector for a rolled material is provided on the output side of the rough rolling mill and the roll gaps on the left and right sides of the finishing rolling mill are subjected to one-side reduction (leveling).

Further, Japanese Patent Laid-Open No. 58-51771 discloses a method of adjusting the left and right roll gaps by the difference between the rolling loads provided on the working side and the driving side.

[0011]

However, in the conventional method of adjusting the left and right roll gaps by one-sided pressing, it is mechanically impossible to match the off-centers of the center of the plate and the center of the roll. . Therefore, the center of the material was originally
In the case of entering with deviation, as shown in FIG. 4, the finishing rolling mill controls the single-sided reduction so as to narrow the roll gap on the working side (Op side), and the center of the material is the center of the roll, that is, the driving side ( If you try to correct the meandering by making it closer to Dr side), the plate will try to move to Dr side.

However, at this time, as shown in FIG. 5, there is a problem that the output side plate generates a one-sided gauge having a cross-sectional shape with a difference in thickness between the left and right plates.

Therefore, for the next stand in the tandem mill such as a finish rolling mill, there is a problem that the interference between both the off-center of the plate and the roll and the single gauge of the plate promotes meandering.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a control method for a roll cloth rolling mill which prevents meandering of rolling material and one-sided gauge.

[0015]

SUMMARY OF THE INVENTION The present invention provides a method for controlling a roll cross rolling mill, in which an upper work roll and a lower work roll can intersect each other at a required angle with respect to a direction perpendicular to the rolling direction. The above-mentioned object is achieved by controlling the meandering of the rolled material by individually setting the cross angle of the upper work roll and the cross angle of the lower work roll.

The present invention also provides a method of controlling a roll cross rolling mill, wherein the upper work roll and the lower work roll can intersect each other at a required angle with respect to a direction perpendicular to the rolling direction. The above object is similarly achieved by controlling the plate thickness difference of the rolled material by individually setting the cross angle and the cross angle of the lower work roll.

[0017]

According to the present invention, in the roll cross rolling machine capable of intersecting the upper work roll and the lower work roll at the respective required angles with respect to the direction perpendicular to the rolling direction, the cross of the lower work roll is provided. By setting the off center of the cross point by shifting the angle and the cross angle of the upper work roll, and matching the off center of the material with the off center of the cross point, that is, the center of the mill, the roll gaps corresponding to both ends of the rolled material can be obtained. It is possible to prevent the plate from meandering and one-sided gauge and to pass the plate straight without generating a difference.

[0018]

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

FIG. 6 is a schematic diagram showing a finish rolling mill having a mechanism for crossing the upper and lower whirl rolls, which is an embodiment of the present invention. In FIG. 6, 1 is a rolled material, 2 is an upper work roll, 4 is a lower work roll, 6 is an upper backup roll, 8 is a lower backup roll, 10 is an upper cross motor, and 12 is a lower cross motor. The upper and lower work rolls 2 and 4 are controlled by 10 and 12 so as to cross each other.

Further, a width end position detector 14 of the rolled material 1 is arranged on the upstream side of the finish rolling mill, and a detection signal of the detector 14 can be sent to a meandering calculator 16 to determine the meandering amount. The upper and lower cross motors 10 and 12 are controlled by an off-center setting command of the cross point from (off-center amount of the center of the plate and the center of the mill).

A plate profile meter 18 for measuring the plate cross-sectional shape of the rolled material 1 is arranged on the downstream side of the finish rolling mill.
The one gauge (left and right plate thickness difference) signal of the profile meter 18 can be sent to the meandering calculator 16, and the left and right roll gap correction values are calculated from the amount of one gauge to set the cross point off center. The upper and lower cross motors 10 and 12 are controlled by the command.

The roll cloth method will be described in detail below.

FIG. 7 is an explanatory view showing the state of the roll cloth. The upper part is a side view of the ends of the upper and lower work rolls, and the lower part is a plan view in which each roll is represented by a line segment to show the cross angle. . In FIG. 7, the geometrical relationship between the cross angle θ of the upper and lower rolls and the roll gap S is expressed as follows.

When the roll gap when the upper and lower rolls are crossed is Se and the upper and lower work roll diameters are equal to Dw, the following equations (1) and (2) are established in ΔABC.

[0025]

[Equation 1]

In FIG. 7, the roll gap is 0 (that is, the roll kiss state) at the center of the roll, and when the upper roll cross angle is θ _U and the lower roll cross angle is θ _L , S
e represents the roll gap change when the cross angle becomes θ = (θ _L + θ _U ) / 2. Further, the following expression (3) is established.

[0027]

[Equation 2]

When EG = b / 2 (distance from the roll center in the plate width direction), the following expressions (4) and (5) can be expressed.

[0029]

[Equation 3]

Therefore, by substituting the equations (4) and (5) into the equation (3), the following equation (6) is obtained.

[0031]

[Equation 4]

Since ΔABC is a right triangle,
The following equation (7) is established by the Pythagorean theorem.

[0033]

[Equation 5]

In this equation (7), (1), (2), (6)
By substituting the equation, the following equation (8) is established.

(Se + Dw) ² = {(b / 2) (tan θ _U + tan θ _L )} ² + Dw ² (8)

From this, the following equation (9) is obtained.

[0037] ^{Se 2 + 2Dw Se = (b} 2/4) {tan 2 θ U + tan 2 θ L +2 tanθ U tan θ L} ... (9)

Since the angle θ is as small as 0 ° <θ <2 ° at most, it can be replaced with tan θ≈θ (rad),
The following expression (10) is established.

Se = b ² · (θ _U ² + θ _L ² +2 θ _U θ _L ) / 8Dw−Se ² (10)

The generally known cross angles θ and S
The relationship of e is θ _U = θ _L = θ, and the influence coefficient is δ (0
If <δ <1) and the above equation is applied, the following (11)
The formula holds.

Se = (b ² θ ² / 2Dw) δ (11)

FIG. 8 shows the off-center (Ze when the cross angle θ _L of the lower roll is shifted by Δθ _L in FIG. 7).
9) is an enlarged view of the triangle Δabc in FIG. The relationship between the deviation of the cross angles of the upper and lower work rolls and the off-center amount of the cross points is geometrically expressed as follows with reference to FIGS. 8 and 9.

In FIG. 9, ∠Hab = θ _L + Δθ _L , ∠
Since Hac = θ _U , the following equation holds.

[0044]

[Equation 6]

This also applies to θ _U → θ _U + Δθ _U , and can be geometrically calculated even when θ _L and θ _U are both displaced from Δθ _L and Δθ _U.

On the other hand, at the off-center of the cross point, the cross point and the mill center coincided with each other. Θ _L = θ
There is a left-right difference in the roll gap compared to when _U.

Further, FIG. 10 shows a state in which the cross point is off center by Ze. At this time, the roll gap on the Dr side is gh (θ _U = θ _L ) to g when the center of the rolled material is aligned with the center of the mill.
h '(θ _L → θ _L + Δθ _L ) x of roll gap on Op side
It changes from y (θ _U = θ _L ) to x'y (θ _L → θ _L + Δθ _L ).

The roll gap difference between the Op side and the Dr side is also obtained from the geometrical relation. Although detailed equations are not described here, the following relational equation (15) is obtained from the equations (11) and (14).
become.

Se (Op −Dr) = f (b, Ze, Dw, θ _U , θ _L , Δθ _U , Δθ _L , ld) (15)

FIG. 11 is a diagram showing the effective roll gap. When the off center occurs by Ze, for example, the cross points θ _L of the lower roll are shifted by Δθ _{L to} shift the cross point by Ze. The center of the rolled material coincides with the center of the mill.

In this way, the roll gap S determined above is obtained.
From e, the meandering calculator 16 sends a cross point off-center setting command to the upper and lower cross motors 10 and 12 to control the roll cross angle.

The present invention is not limited to the above-described embodiment, but it is needless to say that the finish rolling mill has a plurality of stands to control the cross operation before the rolling material is caught. Alternatively, the control may be performed even during biting. Also, without using a detector, the off-center of the plate and the mill, which can be distinguished from the long-term tendency of each day or week estimated from the thickness difference of the material slab and the mechanical play of the rough rolling machine,
It is also possible to set the control amount to the off-center of the cross points of the upper and lower rolls.

[0053]

As described above, according to the present invention,
Since the meandering of the rolled material is controlled as the off-center amount of the cross points of the upper and lower work rolls of the rolling mill, there is an effect that the meandering can be corrected without causing plate thickness deviation on the left and right of the rolled material. .

Further, since the gap difference between the left and right of the rolling rolls can be controlled as the off-center amount of the cross points of the upper and lower work rolls, it has become possible to correct the single gauge of the plate. From the above, there is an excellent effect that good rolled product quality can be obtained without adversely affecting the strip passing property.

[Brief description of drawings]

FIG. 1 is a plan view showing how the rolled material meanders.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 showing a gauge of rolled material.

FIG. 3 is a plan view showing a rolled material which is passing through a roll showing meandering.

FIG. 4 is a front view of a roll during rolling showing conventional meandering control.

FIG. 5 is a front view showing a cross-sectional shape of a rolled material in which one gauge is generated.

FIG. 6 is a configuration diagram showing an outline of a finish rolling mill of the present embodiment.

FIG. 7 is an explanatory diagram showing a state of roll cloth in the present embodiment.

FIG. 8 is an explanatory diagram showing a state of cross angle correction for rolling control in the present embodiment.

FIG. 9 is an enlarged view in which a part of FIG. 8 is enlarged.

FIG. 10 is an explanatory diagram showing cross angle correction in the present embodiment similar to FIG.

FIG. 11 is a diagram showing a state of an effective roll gap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rolled material 2 ... Upper work roll 4 ... Lower work roll 6 ... Upper backup roll 8 ... Lower backup roll 10 ... Upper cross motor 12 ... Lower cross motor 14 ... Width end position detector 16 ... Meandering calculator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B21B 37/28 8315-4E B21B 37/00 116 J

Claims (2)

[Claims] 1. A method of controlling a roll cross rolling mill, wherein an upper work roll and a lower work roll can intersect each other at a required angle with respect to a direction perpendicular to the rolling direction. A method for controlling a roll cross rolling mill, characterized in that the meandering of the rolled material is controlled by individually setting the angle and the cross angle of the lower work roll. 2. A method of controlling a roll cross rolling machine, wherein the upper work roll and the lower work roll can intersect each other at a required angle with respect to a direction perpendicular to the rolling direction. A method for controlling a roll cross rolling mill, characterized in that the difference in plate thickness between rolled materials is controlled by individually setting the cross angles of the lower work rolls.