JP2000140921A - Method for controlling shape in cold tandem mill and shape controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent troubles such as defect in shape, retraction of area and breaking of sheet by taking the case where shift rolling is not executed as a reference, obtaining the variation from the reference of the thickness and the amount of edge drop in the end part of a sheet and elongation percentage difference in the end part of the sheet when the shift rolling is executed and controlling the operating pressure of a bender. SOLUTION: The shift in the width direction of a work roll 8 is controlled based on the command value of the shift amount with a work roll shifting device 3, the measure value of the amount of the edge drop is obtained from the thickness of a rolled stock on the outlet side of No. N stand with a thickness gage 1 and, by comparing it with the target value, the command value of the shift amount of a work-roll shifting device 3 is obtained. On the after No. 2 stand, by taking the thickness or the amount of edge drop in the end part of the sheet when the shift rolling is not executed at No. 1 stand as the reference, obtaining the variation of the thickness or the amount of the edge drop in the end part of the sheet when the shift rolling is executed, obtaining the elongation difference in the end part of the sheet based on this and obtaining the operating pressure of a bender based on this difference, the bending device 5 of each stand is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shape control method and a shape control device for a cold tandem compressor.

[0002]

2. Description of the Related Art In a rolled material after cold rolling, a sharp decrease in the thickness, which is called edge drop, occurs at both ends in the width direction of the plate. It is strongly desired that a rolled product has a minimum edge drop amount.

Conventionally, as a technique for controlling edge drop, at least a first (No. 1) rolling mill capable of shifting a trapezoidal work roll provided with a chamfer (Chamfer) at the roll end in the sheet width direction. In the tandem rolling mill arranged at the stand position of, the edge drop amount was measured by the thickness gauge installed on the exit side of the final stand,
There is a method of performing a comparison operation between the edge drop amount and the target edge drop amount, and performing a shift control of the trapezoidal work roll based on a result of the comparison operation.

Further, as a technique for preventing the occurrence of a defective shape due to shift control of a conventional trapezoidal work roll,
Japanese Unexamined Patent Application Publication No. 60-12213 discloses that the overlap amount (hereinafter referred to as shift amount) between a chamfer portion and a plate end portion of a trapezoidal work roll and the roll bender operating pressure at the time of an optimum shape are substantially reduced. By utilizing the linear relationship, the bender operation pressure is controlled.

[0005]

However, the prior art described above has the following problems.

[0006] After the second (No. 2) stand, the edge drop amount of the incoming rolled material changes with the edge drop control in the first stand. Therefore, when rolling is performed using a flat roll, a change in elongation at the end of the plate occurs, resulting in a defective shape. However, the above-mentioned prior art publication does not suggest any countermeasures against the shape defect.

Also, in the above-mentioned publication of the prior art, in order to enhance the edge drop control effect, No. 2
When using a trapezoidal work roll even after the stand,
o. Since the edge drop amount of the incoming rolled material changes by the edge drop control in one stand, As in the case of one stand, the bender operation pressure in the optimum shape cannot be determined only by the shift amount.

For the reasons described above, according to the above-mentioned prior art publication, in the case where edge drop control by shift rolling of a trapezoidal work roll is performed in a stand after the first stand or the second stand, the second stand is used. The subsequent shape failure cannot be prevented, and operation troubles such as drawing and plate breakage have been a problem.

The present invention has been made to solve the above-mentioned problems of the prior art, and prevents a shape defect occurring after the second stand and prevents operation troubles such as drawing and plate breakage. It is an object of the present invention to provide a shape control method and a shape control device in a cold tandem rolling mill that can prevent such a problem.

[0010]

In order to achieve the above object, an invention according to claim 1 is to provide at least a first rolling mill capable of shifting a work roll having a chamfer at a roll end in a sheet width direction. Using a cold tandem rolling mill disposed on the stand, the measured value of the steel plate edge drop amount on the exit side of the final stand and the target edge drop amount set value of the steel plate are compared, and based on the comparison calculation value, the trapezoid is used. In a shape control method for a cold tandem compressor that performs shift control of a work roll in a plate width direction, in a second stand or later, a plate thickness or a plate thickness of a plate end when shift rolling is not performed in the first stand. The edge drop amount is used as a reference, and the reference value of the plate thickness or the edge drop amount at the plate end when shift rolling is performed in the first stand with respect to the reference. Calculating the amount of change, calculating the difference in elongation at the end of the plate based on the amount of change, and controlling the bender operating pressure on the bending means of the work roll in each of the stands based on the obtained difference in elongation. A shape control method in a cold tandem rolling mill characterized by the following.

According to a second aspect of the present invention, a rolling mill capable of shifting a work roll having a chamfer at a roll end in a sheet width direction is provided on at least a first stand. In a cold tandem rolling mill, a work roll shift means for performing shift control of the work roll in the sheet width direction based on a shift amount command value, and an edge for obtaining an edge drop amount measurement value from the sheet thickness of the exit side rolled material of the final stand. A drop amount measuring means, a shift amount command value calculating means for obtaining a shift amount command value of the work roll shift means based on a comparison between the edge drop amount measured value and a target edge drop amount, When the shift rolling is not performed in the first stand, the first stand is used as a reference based on the thickness of the plate end or the edge drop amount. Elongation difference rate calculating means for obtaining a change amount of the sheet thickness or the edge drop amount at the end of the sheet when the shift rolling is performed in a standard manner, and obtaining an elongation difference rate of the end part of the sheet based on the change amount; A bender operation pressure calculating means for obtaining a bender operation pressure based on the difference ratio, and applying the bender operation pressure to a work roll bending means provided in each of the stands, and a shape control device in a cold tandem rolling mill. is there.

According to the first or second aspect of the present invention, when shift rolling of a trapezoidal work roll is performed at the first stand, a difference in elongation occurring after the second stand is determined and corrected. By determining the bender operation pressure applied to the bending means of the work roll to be performed and controlling the bending of the bending means, it is possible to prevent a shape defect occurring after the second stand.

[0013] Also, in the case of performing the shift rolling of the trapezoidal work crawl on and after the second stand, it is possible to appropriately control the bending of the work roll bending means. Accordingly, it is possible to prevent operational troubles such as drawing and breaking of the plate due to a defective shape after the second stand.

[0014]

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

According to the present invention, there is provided a feedback control system for measuring a thickness change at a position a distance from an end in the width direction by a thickness gauge and controlling a bender operating pressure based on the measured thickness change. In addition, there is a prediction control method of predicting the thickness change amount by calculation and controlling the bender operation pressure.

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
FIG. 1 is a diagram showing a schematic configuration of the embodiment, and FIG. 1 shows a feedback control method.

In the first embodiment, a rolling mill capable of shifting a trapezoidal work roll 8 with a chamfer formed at the roll end in a sheet width direction is provided at least on a first stand. The machine is configured as follows.

A work roll shift means for controlling the shift of the work roll 8 in the sheet width direction based on the shift amount command value, for example, the work roll shift device 3, and a final (No.
N) Edge drop amount measuring means for obtaining the measured value of the edge drop amount from the thickness of the rolled material at the end of the stand at the final stand, for example, a sheet thickness meter 1, the measured edge drop amount obtained by the sheet thickness meter 1, and the target edge drop amount The shift amount command value calculating means for calculating the shift amount command value of the work roll shift device 3 based on the comparison of
After the stand of (No. 2), the plate when the shift rolling is performed in the first stand based on the thickness of the plate end or the edge drop amount when the shift rolling is not performed in the first stand. An elongation difference calculating means, for example, an elongation difference ratio calculating device 6 for obtaining a change in the thickness of the end portion or the edge drop amount and obtaining a difference in elongation at the end of the plate based on the change amount; A bender operation pressure calculating means for obtaining a bender operation pressure based on the elongation difference rate from the calculation device 6 and applying the bender operation pressure to the work roll bending device 5 provided in each stand, for example, a bender operation pressure calculation device 4, 7 is a shape control device in a cold tandem rolling mill provided with No. 7.

The thickness of the rolled material at the entrance and exit of each stand after the second (No. 2) stand is measured by a thickness gauge 1 'installed between the stands. It has become. Further, a flat work roll 9 is provided on each of the stands after the second stand,
Each flat work roll 9 can be bent by a work roll bending device 5. Further, the work roll bending device 5 after the second stand inputs the sheet thickness detected by each of the two thickness gauges 1 ′ to the difference in elongation difference calculating device 6, and calculates the difference in elongation obtained here. The bender operation pressure is input to the bender operation pressure calculation device 7 and the calculated bender operation pressure is applied to the work roll bending device 5.

In addition, No. As shown in FIG. 7, one stand shifts the trapezoidal work roll 8 with chamfer in the sheet width direction (shift direction indicated by an arrow), and rolls the chamfered portions 8a at both ends of the material 13 to be rolled. .

By the thickness gauge 1 provided on the exit side of the last (No. N) stand in FIG. 1, the position of the distance a and the position of the distance b from the widthwise end of the exit side rolled material of the final stand. Is measured, and the edge drop amount is calculated as heb.
Determined from -hea.

In this embodiment, the distance a = 5 mm and the distance b
= 25 mm. The shift amount calculating device 2 calculates the shift amount of the trapezoidal work roll 8 based on a comparison operation between the measured edge drop value obtained by the thickness gauge 1 and the target edge drop amount. The calculated shift amount is No. It is input to a work roll shift means of one stand, for example, the work roll shift device 3, and roll shift control is performed.

The thickness of the rolled material at the entrance and exit of each stand after the second (No. 2) stand is measured by a thickness gauge 1 'installed between the stands. The measured plate thickness is input to a difference in elongation calculating means, for example, a difference in elongation calculating device 6. In the elongation difference rate deviation calculating device 6, N
o. The sheet thickness of the sheet edge measured before performing the shift rolling in one stand is recorded as a reference sheet thickness, and the deviation from the sheet thickness of the sheet edge measured after the shift rolling is expressed by Equation (1).
Is calculated by

[0024]

(Equation 1)

[0025] However, hea ^{i *,} hea ^o * represents a reference thickness of a position at a distance a from the end portion in the width direction of the input and output side rolled material, hea ^i, hea ^o is input which is measured after the shift rolling · Represents the thickness of the same position of the exit rolled material, Δhe ⁱ , Δ
hea ^o represents the amount of change from the reference plate thickness.

[0026] Then, from the later-described formula (4), the elongation difference ratio Derutaipushironx ^a plate end portion is calculated. Calculated Δεx
^a is input to a bender operation pressure calculation means, for example, a bender operation pressure calculation device 7.

The bender operation pressure calculator 7 determines a bender operation pressure ΔJ based on the following equations (5) to (7).

The determined bender operation pressure ΔJ is input to a work roll bending device such as a hydraulic cylinder, for example, a work roll bending device (bender device) 5 for bender control.

On the other hand, no. In one stand, FIG.
The bender operation pressure calculation device 4 in the middle utilizes the fact that the shift amount and the optimum bender operation pressure have a linear relationship,
The bender operating pressure for one stand is determined. On the basis of this, in the work roll bending device 5,
Roll bending of one stand is performed.

Next, the effects of the embodiment of the present invention will be described. The principle of the bender operation method after the second stand will be described below. In addition, No. 1
The stand implements a conventional method of providing the bender operation amount as an amount proportional to the shift amount.

In the cold rolling, the range in which the edge drop can be controlled by shift rolling is a certain area where the material deformation occurs in the width direction of the rolled material, and the area is about 10 times the sheet thickness from the end of the sheet. Range of length. The distance from the edge of the plate at the boundary position of the edge drop control area is defined as b.

Further, the edge drop amount is defined as a difference between the plate thickness at the position of the distance b from the width direction end and the plate thickness at the position of the distance a closer to the width direction end than the position of the distance b. For example, distance a = 5 mm from the width direction end, distance b = 25 m
m.

The plate thickness hc at the center of the plate width, the plate thickness hea at a distance a from the end in the width direction, and the plate thickness he at a distance b.
Assuming b, the center crown amount is represented by hc-heb, and the edge drop amount is represented by hc-hca.

The elongation difference ratio .epsilon.x ^b position of the plate width central portion and the distance b from the end portion in the width direction of the steel sheet case without shifting the rolling trapezoidal work roll 8, Table by the amount of change of the center crown ratio before and after rolling And is calculated from equation (2). This change in the center crown ratio is caused by roll deflection during rolling and roll surface flattening.

Here, the suffixes i and o in the equation (2) indicate the input side and the output side, respectively.

[0036]

(Equation 2)

On the other hand, the bender operation pressure J is determined based on the equation (3), and the determined bender operation pressure J is determined.
The work roll bending device (bender device) 5 is controlled so that With such vendor control,
The elongation difference rate εx ^b = 0, that is, a state where the shape is controlled to be flat is set as a reference state. Where K in equation (3)
₁ is a influence coefficient vendor operating pressure J to elongation difference ratio .epsilon.x ^b position of the distance b from the sheet width central portion and the end portion in the width direction is determined by experiments and numerical calculations, the plate width, the function of the plate thickness, etc. It is.

[0038]

(Equation 3)

Next, no. No. 1 stand and No. In a state where both stands are controlled flat (reference state),
No. Shift rolling of the trapezoidal work roll 8 was performed at one stand. When rolling was performed using flat work rolls 9 on two stands, 2 stand entrance,
FIGS. 5A and 5B show the ratio of the sheet thickness to the sheet thickness at the center of the sheet width of the exit-side rolled material (hereinafter, referred to as the sheet profile ratio). FIG. 5 (c) shows the change from.

The symbol (1) in FIG. In the case of one stand without trapezoidal shift rolling, that is, the reference state is shown. After performing the shift rolling of the trapezoidal work roll 8 in one stand, This is a case where rolling is performed with a bender operation pressure J in a reference state using a flat roll at two stands.

No. Trapezoidal work roll 8 per stand 8
When the shift rolling of No. In the two stands, the rolled material whose thickness changes at the position of the distance a from the end in the width direction is rolled. At this time, No. In the two stands, the plate edge is concentrated and reduced, and accordingly, a local change in the elongation difference rate occurs at the plate edge. The change Δεx ^a of the local difference in elongation at a position a distance a from the end in the width direction is expressed by Expression (4).

Here, Δhea is a distance a from the end in the width direction.
The change amount of the plate thickness at the position is represented, and hc represents the plate thickness at the center of the plate width. Note that the subscripts i and o represent the incoming side and the outgoing side, respectively. γ is a shape change coefficient, which is determined by an experiment or the like, and represents a ratio of an elongation strain to a rolling strain at a plate edge.

The reason why the shape change coefficient γ is considered in the equation (4) is that the material deformation in the width direction occurs at the end of the plate where the material is not constrained. This is because the ratio of the ratio takes a value in the range of 0 <γ <1.0.

[0044]

(Equation 4)

[0045] even if elongation difference ratio Derutaipushironx ^a, does not cause buckling, that is, it is generally known that the presence of shaped dead zone does not become defective shape (e.g., "Theory and Practice of plate rolling" , Japan Iron and steel Association, p.96), the shape defect occurs in the case where Derutaipushironx ^a exceeds the range of the shape dead zone.

On the other hand, if the bender operation pressure is changed so that Δεx ^a = 0, the symbol (3) in FIG.
As shown in the figure, the differential elongation at the edge of the plate is reduced, but on the other hand, the differential elongation is changed at a portion other than the edge of the plate, and if the ratio exceeds the range of the shape dead zone, the shape is poor. Occurs.

As one of the ideas of the bender operating pressure,
As shown by a symbol (4) in FIG.
E at the position of the distance a^aAnd reduce
The difference in elongation occurring in other parts due to
Shape dead zone (-ε_L ^L~ Ε_L ^U)
Good shape by adjusting the bender operation pressure
Can be obtained.

[0048] However, the lower limit elongation difference ratio of epsilon _L ^L shape dead zone for the medium elongation, epsilon _L ^U represents an upper limit differential expansion rate of the shape deadband for the ear wave. For example, ε _L ^L , ε
_L ^U is given by equation (5). Where B is the board width and h
c ^o represents the thickness of the plate width central portion of the outlet side. A ^L , a
^U is a constant determined by experiment, usually a ^L = 40, a ^U
= 80. This shows that the width of the shape dead zone in the ear wave area is wider than that in the middle extension area.

[0049]

(Equation 5)

The bender operation pressure J as described above is calculated from equations (6) and (7). That is, first, considering the difference between the ear wave and the middle stretch area of the shape dead zone,
The average elongation difference rate Δεm of the region from the distance a to the distance b from the end in the width direction is calculated from Expression (6). However, equation (6)
Derutaipushironx ^b in the in the reference state is zero.

[0051]

(Equation 6)

From the equation (7), the average elongation difference rate Δε
The bender operation pressure ΔJ corresponding to m is calculated. However,
K ₂ in the equation (7) represents the influence coefficient of the operating pressure on the average elongation difference Δεm.

[0053]

(Equation 7)

As described above, as shown in FIG. When the shift rolling of the trapezoidal work roll 8 was performed at one stand, The elongation differential rate Δεx ^a occurring after the second stand is obtained from the equation (4), and the bender operation pressure J for correcting the difference is expressed by the equations (5) to
Determined from equation (7), work roll bending device 5
By performing the vendor control of No. Shape defects occurring after the second stand can be prevented.

<Second Embodiment> FIG. 2 is a schematic configuration diagram for explaining a second embodiment, and is a configuration diagram of a control system when performing prediction control. The difference from FIG. 1 is that the elongation difference rate calculation device 6 and the thickness gauge 1 ′ are not provided, and a calculation device 10 is newly provided instead.

The calculation device 10 has the Based on the shift amount of one stand, No. The thickness change at the end of the rolled material on the incoming and outgoing sides after the second stand is predicted and calculated, and the above equation (4) is calculated.
Calculating a differential expansion rate Derutaipushironx ^a more Itatan portion. The calculated difference in elongation Δεx ^a is input to the bender operation pressure calculation device 7, and the bender operation pressure ΔJ is determined from Expressions (5) to (7). The determined bender operation pressure ΔJ is input to the work roll bending device 5 and roll bending is performed.

An example of a calculation procedure performed in the calculation device 10 will be described below with reference to FIG.

No. When a trapezoidal work roll was shift-rolled on one stand, The amount of change Δhe ^{o o} of the plate thickness at a position a distance from the width direction end of the one-stand exit side rolled material from the reference plate thickness is obtained by equation (8) (S1). However,
α is a constant representing the ratio of the transfer of the chamfered portion 8a of the trapezoidal work roll 8 to the material 13 to be rolled.

FIG. 8 shows an example of the constant α, which is determined by an experiment or the like according to the deformation resistance and the sheet thickness of the rolled material. Equation (8)
Is the chamfer portion 8 of the trapezoidal work roll 8
The taper angle a and WRδ represent the shift amount.

[0060]

(Equation 8)

No. When the flat work roll 9 is used in two or more stands, Δhe of the rolled material on the exit side of each stand is used.
^ao is determined from equation (9). Here, (1-α) represents the ratio of the edge drop of the incoming rolled material to the outgoing rolled material. Further, hc represents a plate thickness at a central portion of the plate width, and subscripts i and o represent an entrance side and an exit side.

[0062]

(Equation 9)

Using the calculation formulas (8) and (9) described above, calculation is sequentially performed from the first stand to the last stand according to the calculation flow shown in FIG. 9A (S2 to S7).
However, the subscript i in FIG. And N represents the total number of stands of the tandem rolling mill.

<Third Embodiment> FIG. 3 shows a third embodiment of the present invention.
FIG. 2 is a schematic configuration diagram illustrating an embodiment of the present invention, and illustrates a feedback control method as in FIG. No. 1 stand and No. This is a cold tandem rolling mill in which a plurality of stands (two or more stands) after the second stand and a rolling mill capable of shifting the trapezoidal work roll 8 with a chamfer in the sheet width direction are arranged.

Each trapezoidal work roll 8 is configured to be driven by the work roll shift device 3.
The work roll shift device 3 calculates the shift amount of the work roll 8 by inputting the shift amount WRδ calculated by the shift calculation device 2 as in FIG.

In addition, No. After performing the shift rolling of the trapezoidal work roll 8 in one stand, In the case of performing the shift rolling of the trapezoidal work roll 8 even with two stands, 2
FIG. 6A shows the plate profile ratio on the stand entrance side (plate profile ratio on the exit side of No. 1 stand).
o. FIG. 6B shows the plate profile ratio at the exit side of the second stand. FIG. 6 (c) shows a change in the differential elongation rate of one stand from the reference state. FIG. 6D shows a change in the difference in elongation between the two stands from the reference state. The symbol (1) in FIG. 1 and 2 stands without trapezoidal shift rolling. After performing the shift rolling of the trapezoidal work roll in one stand,
This is the case where the trapezoidal work roll is shifted even in the two stands and the rolling is performed with the bender operating pressure in the reference state.

When comparing FIG. 6 (c) and FIG. 6 (d), the change of the elongation difference rate is different between the two. The conventional control method for one stand is No. When applied to the two stands as it is, as shown by a symbol (3) in FIG.
It increases the tendency of the ear to stretch, and conversely deteriorates the shape.

However, as in the present invention, the differential elongation Δεx ^a
, And controlling the bender operation pressure in accordance therewith makes it possible to control to a good shape.

Structures other than those described above are the same as those in FIG. 1, and the operational effects are the same as those in FIG. Therefore, No.
Even in the case where the trapezoidal work roll 8 is subjected to shift rolling in the second and subsequent stands, appropriate bender control of the work roll bending device 5 can be performed. It is possible to prevent operational troubles such as drawing and plate breakage due to defective shape after the second stand.

<Fourth Embodiment> FIG. 4 is a schematic block diagram showing a fourth embodiment, which is a prediction control method similar to FIG. The difference from FIG. Instead of providing the flat work rolls 9 provided after the second stand, trapezoidal work rolls 8 with chamfers are provided instead,
Each trapezoidal work roll 8 is a cold tandem rolling mill in which rolling mills that can shift in the sheet width direction are arranged. The other points are the same as those in FIG.

Hereinafter, an example of a calculation procedure performed inside the calculation device 10 will be described with reference to FIG. 9B.

In the fourth embodiment having such a configuration, in the case of No. No. 1 when the shift rolling of the trapezoidal work roll was performed in one stand. The amount of change Δ from the reference plate thickness at the position a distance a from the width direction end of the rolled material on the stand side.
"he ^o" is obtained from the equation (8) (S8). And No. Calculate the thickness change after the second stand. When shift rolling is performed using the trapezoidal work roll 8, Δhe ^o of each stand exit side rolled material is calculated by the equation (10).
Find more.

[0073]

(Equation 10)

When the shift rolling of the trapezoidal work roll 8 is not performed, Δhea of the rolled material on the exit side of each stand is used.
^o is obtained from equation (9).

Using equations (8) to (10) shown above,
According to the calculation flow shown in FIG. 9B, calculation is sequentially performed from the first stand to the last stand (S10 to S16).
However, the subscript i in FIG. 1 and N represents the total number of stands of the tandem rolling mill.

[0076]

<First Embodiment> FIG. 10 shows a four-stand cold tandem rolling mill according to a first embodiment of the present invention. Only one stand has the chamfer part 8 of FIG.
A rolling mill capable of shifting the trapezoidal work roll 8 having the taper angle (a) of 0.13 ° in the width direction of the plate was disposed. Also,
The thickness gauge 1 for measuring the edge drop amount is installed on the exit side of the last stand. The shift control of one stand is performed. N
o. The predictive control method of the present invention was applied to control of the bender operation pressure of a few stands. In addition, No. In one stand, a conventional method of giving the bender operation amount as an amount proportional to the shift amount is performed. In addition, No. In the four stands, the present invention was not applied because the final product shape was monitored by a shape meter to perform bender feedback control.

Hereinafter, in the cold tandem rolling mill shown in FIG.
The result of performing a rolling test for confirming the effects of the present invention is shown.
The rolled material is a base material having a sheet width of 900 mm, a sheet thickness of 2.55 mm, and a ratio of the edge drop amount to the sheet thickness at the center of the sheet width (hereinafter, referred to as an edge drop ratio) of 10%.
m. The rolling reduction of each stand is 24.5%
(# 1STD), 31.5% (# 2STD), 38.0
% (# 3STD) and 28.4% (# 4STD).
Also, the target edge drop rate on the exit side of the final stand,
No. 3% and 0%. The shift amount of one stand increased as the target edge drop ratio decreased, and became 75 mm and 95 mm, respectively.

Hereinafter, the case where the present invention is applied will be described in detail.

The change in the plate thickness at the position of the distance a from the end in the width direction was determined according to the calculation flow shown in FIG. No. 1 stand. Calculations were sequentially made up to three stands. And
From equation (3), the elongation difference rate Δ at the position of distance a from the end in the width direction
The εx ^a calculated, No. from the equation (5) to (7) The bender operating pressure for a few stands was calculated.

In the calculation, the constant α in the equations (8) to (9) is a value obtained by experiment. 1 to No. The values were 0.6, 0.5, and 0.4 for three stands, respectively. The reason that α is smaller in the latter stand is that the work hardening of the rolled material in the latter stand makes it difficult for the material deformation in the sheet width direction to occur.

The constant γ in the equation (4) was a value obtained by experiment and was set to 0.015. In addition, the influence coefficient K ₂ of 3.8 × 10 ⁵ the best vendor for the mean elongation difference ratio Δεm position distance b from the position of the distance a from the end portion in the width direction.

[0082]

[Table 1]

Table 1 shows the calculated value Δhea of the change in plate thickness at a distance a from the end in the width direction, and the calculated values Δεx ^a and Δε of the difference in elongation when the bender control according to the present invention is not performed.
x ^b, calculated values Derutaipushironx ^a differential expansion rate after vendor operating pressure ΔJ and vendor operation according to the present invention, showing the Δεx ^b. Note that ΔJ is No. This is a deviation amount from the bender operation pressure after shift rolling with reference to the bender operation pressure before roll shift rolling in one stand.

If the vendor control according to the present invention has not been performed, 2,3 In either stand, elongation Saritsu position a distance a from the end portion in the width direction is beyond the elongation difference ratio epsilon _L ^U max shape dead zone with respect to edge waving, edge waving shape occurs.

However, according to the present invention, the bender operation force is determined such that the ear wave shape is relaxed and the difference in elongation at the position of the distance b is also within the range of the shape dead zone.

[0086]

[Table 2]

Table 2 shows the measurement results of the plate shapes when the present invention is applied and when the present invention is not applied. The plate shapes shown in the table indicate that the rolling mill was temporarily stopped and 2 stand and No. This is the result of sampling the rolled material at the exit side of the three stands and measuring the value using an off-line flatness meter. Based on the steepness at the center of the plate, the distance a (= 5 m) from the end in the width direction
The difference from the steepness of the position m) is shown. In addition, the steepness of the position at the distance b (= 25 mm) from the end in the width direction was 0% in both cases where the present invention was applied and not applied.

No. In the two stands, when the present invention was not applied, an ear wave shape was generated in both cases of the target edge drop rate of 3% and 0%. The reason is as follows. When shift rolling is performed at one stand, edge-up occurs at the end of the plate. This is because, in the two stands, the elongation rate in the longitudinal direction of the plate edge increases. On the other hand, when the present invention is applied, the steepness is 0% under all conditions, and it can be seen that a good shape can be realized.

Also, No. In the three stands, No. The edge up of the plate edge generated in one stand is No. 1. Since it is alleviated by two stands, even if the present invention is not applied, N
o. The degree of the shape defect of the three stands is No. It is smaller than two stands. However, in both cases where the target edge drop amount is 3% or 0%, no. Since the amount of edge-up generated in one stand is large, no. Ear waves also occurred on the exit side of the three stands. On the other hand, when the present invention was applied, the steepness was 0% under all conditions, and a good shape was realized.

Table 3 shows that the tandem rolling mill shown in FIG.
o. When the edge drop control is performed in one stand, no. The frequency of occurrence of plate drawing due to a defective shape of a few stands is shown. According to the application of the present invention, no. Two, three
The plate drawing at the stand was greatly reduced.

As described above, in the cold tandem rolling mill having the configuration shown in FIG.
o. The effects when applied to a few stands are shown.

<Second Embodiment> FIG. 11 shows a cold tandem rolling mill of the same configuration as that of FIG. FIG. 3 shows a control system configuration diagram when controlling the bender operation pressure of the second and third stands by the feedback control method according to the present invention. As a result of a rolling test for confirming the effect of this control system, the same effect as the predictive control method of FIG. 10 was obtained.

<Third Embodiment> FIG. 12 shows a cold tandem rolling mill having four stands in total. The taper angle (θ) of the chamfer portion 8a of FIG.
A rolling mill capable of shifting a 0.13 ° trapezoidal work roll in the sheet width direction was arranged. In addition, a thickness gauge 1 for measuring the edge drop amount was installed on the exit side of the final stand. 1 to N
The roll shift control of the o3 stand is performed. No. Two, three
The prediction control method of the present invention was applied to control of the bender operation pressure of the stand. In addition, No. In one stand, a conventional method of giving the bender operation amount as an amount proportional to the shift amount is performed.

In addition, No. In the four stands, the present invention was not applied because the final product shape was monitored by a shape meter to perform bender feedback control.

Hereinafter, a cold tandem rolling mill shown in FIG.
The result of performing a rolling test for confirming the effects of the present invention is shown.
As a rolled material, a base metal sheet having a sheet width of 900 mm, a sheet thickness of 2.1 mm, and an edge drop ratio of 10% was rolled to 0.7 mm.
The rolling reduction of each stand is 24.5% (# 1 STD), 3
1.0% (# 2STD), 20.0% (# 3STD),
20.0% (# 4STD). The target edge drop rate on the exit side of the final stand was 6%, 3%, and 0%. 1 to No. The shift amounts of the three stands increased as the target edge drop ratio decreased, and were as follows.

Edge drop ratio Shift amount (No. 1 stand, No. 2 stand, No. 3 stand) 6% − (50 mm, 5 mm, 0 mm) 3% − (90 mm, 20 mm, 10 mm) 0% − (110 mm, 25 mm, 15 mm) The change in the plate thickness at a distance a from the width direction end is shown in FIG.
According to the calculation flow shown in FIG. No. 1 stand.
Calculations were sequentially made up to three stands. Then, the elongation differential rate Δεxa at ^a position a distance a from the end in the width direction is calculated from Equation (4), and No. The bender operating pressure for a few stands was calculated.

In the calculation, the constant α in the equations (8) and (10) is a value obtained by experiment. 1 to No. The values were 0.6, 0.5, and 0.4 for three stands, respectively.

The constant γ in the equation (4) was a value obtained by experiment and was set to 0.015. In addition, the influence coefficient K ₂ of 3.8 × 10 ⁵ the best vendor for the mean elongation difference ratio Δεm position distance b from the position of the distance a from the end portion in the width direction.

[0099]

[Table 3]

Table 4 shows the thickness change Δhea at a distance a from the end in the width direction, the calculated values of the difference in elongation Δεx ^a and Δεx ^b when the bender control according to the present invention is not performed, and the bender operating pressure according to the present invention. calculated differential expansion rate after ΔJ and vendor operation Δεx ^a, shows the Δεx ^b.

If the vendor control according to the present invention is not performed, When the target edge drop rate is 3% or 0% in the 2nd stand, No. In 3 stand in all conditions, elongation Saritsu position a distance a from the end portion in the width direction is beyond the elongation difference ratio epsilon _L ^U max shape dead zone with respect to edge waving, edge waving shape occurs. However, according to the present invention, the bender operation pressure is determined so that the ear wave shape at the position of the distance a is alleviated and the difference in elongation at the position of the distance b is also within the range of the shape dead zone.

[0102]

[Table 4]

Table 5 shows the results of actual measurement of the plate shape when the present invention was applied and when it was not applied. The plate shapes shown in the table indicate that the rolling mill was temporarily stopped and 2 stand and No. This is a result of sampling a rolled material at the exit side of the three stands and measuring the value using an off-line flatness meter. Based on the steepness at the center of the plate as a reference, the distance a (= 5 m) from the end in the width direction
The difference from the steepness of the position m) is shown. In addition, the steepness of the position at the distance b (= 25 mm) from the end in the width direction was 0% in both cases where the present invention was applied and not applied.

No. In the case of the two stands, when the present invention was not applied, even when the target edge drop rate was 3% or 0%, an ear wave shape was generated.

The reason is as follows. When roll shift rolling is performed in one stand, a large edge-up occurs at the end of the plate. This is because even if shift rolling is performed in two stands, the difference in elongation at the end of the plate increases, resulting in an ear wave shape. On the other hand, when the present invention is applied, the steepness is 0% under all conditions, and it can be seen that a good shape can be realized.

Also, No. In the three stands, when the present invention was not applied, ear waves were generated under all conditions. In contrast,
When the present invention was applied, the shape could be controlled well within the target management range under all conditions.

Table 6 shows that the tandem rolling mill shown in FIG.
o. When the edge drop control is performed in one stand, no. The frequency of occurrence of plate drawing due to a defective shape of a few stands is shown. According to the application of the present invention, no. Two, three
Plate drawing at the stand has been greatly reduced.

As described above, in the cold tandem rolling mill having the configuration shown in FIG.
o. The effects when applied to a few stands are shown.

<Fourth Embodiment> FIG. 13 shows a cold tandem rolling mill having the same configuration as that of FIG. FIG. 3 shows a control system configuration diagram when controlling the bender operation pressure of the second and third stands by the feedback control method according to the present invention. As a result of a rolling test for confirming the effect of the control system, the same effect as that of the predictive control method shown in FIG. 12 was obtained.

[0110]

According to the present invention, when a rolling mill capable of shifting a trapezoidal roll with a chamfer in the sheet width direction is arranged on at least the first stand of a tandem rolling mill, the second stand is used. Shape defects occurring thereafter can be corrected appropriately, and operation troubles caused by the shape defects can be prevented. As a result, the operation rate of the rolling mill increases, and the productivity improves. Further, since the number of shape defects is reduced, the production yield is improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention, and is a configuration diagram of a control system in the case of feedback control.

FIG. 2 is a diagram for explaining a second embodiment of the present invention, and is a configuration diagram of a control system in the case of predictive control.

FIG. 3 is a diagram for explaining a third embodiment of the present invention, and is a configuration diagram of a control system in the case of feedback control.

FIG. 4 is a diagram for explaining a fourth embodiment of the present invention, and is a configuration diagram of a control system in the case of predictive control.

FIG. 5 is a diagram for explaining the embodiment of FIG. FIG. 5 is a distribution diagram of a plate crown ratio and a difference in elongation of the stand of No. 2;

FIG. 6 is a diagram for explaining the embodiment of FIG. FIG. 5 is a distribution diagram of a plate crown ratio and a difference in elongation of the stand of No. 2;

FIG. 7 is an explanatory diagram of a positional relationship between a trapezoidal work roll and a rolled material for explaining the embodiment of FIG. 1;

FIG. 8 is an explanatory diagram of a constant α in the embodiment of FIG. 1;

FIG. 9 is a diagram illustrating the operation of the embodiment shown in FIGS. 2 and 4; No. 1 stand only and No. The flowchart of the cold tandem rolling mill which has a shift rolling mill in a plurality of stands after the 2nd stand.

FIG. 10 is a diagram for explaining the first embodiment of the present invention, and is a configuration diagram of a control system in the case of predictive control.

FIG. 11 is a diagram for explaining a second embodiment of the present invention, and is a configuration diagram of a control system in the case of feedback control.

FIG. 12 is a diagram for explaining a third embodiment of the present invention, and is a configuration diagram of a control system in the case of predictive control.

FIG. 13 is a diagram for explaining a fourth embodiment of the present invention, and is a configuration diagram of a control system in the case of feedback control.

[Explanation of symbols]

 1, 1 ': thickness gauge 2: shift amount calculating device 3: work roll shift device 4: bender operating pressure calculating device 5: work roll bending device 6: elongation difference rate deviation calculating device 7: bender operating pressure calculating device 8: Trapezoidal work roll with chamfer 9 ... Flat work roll 10 ... Computing device 11 ... Shape gauge 12 ... Feedback shape control device

Continuation of the front page (72) Inventor Seisaku Matsukage 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term in Nihon Kokan Co., Ltd. (reference) 4E024 AA04 DD02 DD05 DD08 EE01

Claims (2)

[Claims] 1. A cold tandem rolling mill in which at least a first stand is provided with a rolling mill capable of shifting a work roll having a chamfer formed at a roll end in a sheet width direction, at a final stand exit side. A shape control in a cold tandem compressor that compares a measured value of a steel plate edge drop amount with a target set value of a target edge drop amount of a steel plate, and performs a shift control of the trapezoidal work roll in a plate width direction based on the comparison calculated value. In the method, after the second stand, the shift rolling in the first stand is performed on the basis of the thickness or the edge drop amount at the end of the sheet when shift rolling is not performed in the first stand. The amount of change in the plate thickness or the edge drop amount of the plate end from the above-described reference when performing the above is obtained, and the difference in elongation at the plate end is obtained based on the amount of change. A shape control method for a cold tandem rolling mill, comprising controlling a bender operation pressure on a bending means of a work roll provided in each of the stands based on the obtained difference in elongation. 2. A cold tandem rolling mill in which at least a first stand is provided with a rolling mill capable of shifting a work roll having a chamfer formed at a roll end in a sheet width direction, wherein a shift amount command is issued. Work roll shift means for performing shift control in the sheet width direction based on the value, edge drop amount measurement means for obtaining an edge drop amount measurement value from the sheet thickness of the exit side rolled material of the final stand, and the edge drop amount measurement value and the target A shift amount command value calculating means for obtaining a shift amount command value of the work roll shift means based on a comparison of the edge drop amount; and a plate in a case where shift rolling is not performed in the first stand after a second stand. Based on the thickness of the edge or the edge drop amount, the thickness of the edge of the plate when shift rolling is performed in the first stand is also Or elongation difference calculating means for obtaining a change amount of the edge drop amount, and calculating a difference in elongation of the plate end portion based on the change amount; determining a bender operating pressure based on the difference in elongation; A bender operation pressure calculating means for applying a pressure to a work roll bending means provided in each of the stands, and a shape control device in a cold tandem rolling mill.