JPS62244507A - Control method for edge drop for sheet rolling - Google Patents

Abstract

PURPOSE:To prevent, etc. the variance of an edge drop, etc., by adjusting the shift quantity and bender force of work rolls in accordance with the difference between the edge drop of a sheet before and after rolling and the target value thereof. CONSTITUTION:A tapered part 6a is provided to the roll barrel end of the work roll 6. A roll shift mechanism 13, and a roll bender 11, a roll shift 14 of an intermediate roll 7, and a coolant supplying device 16 as shape control means are respectively disposed. Edge drop detectors 18, 20 are respectively disposed to the inlet side and outlet side of a rolling mill 5. The edge drop before and after rolling of the sheet 1 is detected and the difference from the target value is determined. The roll shift 13 and bender 11 are adjusted in accordance with said difference. The variance of the edge drop is prevented and the generation of edge cracks at the sheet ends is prevented by the above- mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This publication relates to a method of controlling edge drop of a plate during plate rolling.

(Prior Art) It is desirable that the rolled plate has a small edge drop and a good shape, that is, the flatness of the plate is uniformly good not only in the longitudinal direction of the plate but also in the width direction of the plate. In particular, recently, requirements regarding the edge drop and shape of rolled plates have become more severe.

One method for controlling edge drop is to adjust the shift in the width direction of a work roll whose roll body end is tapered.

For example, in the technique disclosed in Japanese Unexamined Patent Publication No. 58-209402, the shift in the sheet width direction of a pair of tapered work rolls is adjusted in accordance with the sheet width. Also, JP-A-60-
In the technology disclosed in Japanese Patent No. 12213, the edge drop amount of the steel plate is measured from the plate thickness gauge at the exit side of the final stand ((i is compared with the target edge drop m setting value, and based on this comparison calculation value, Shift control of the work rolls and operation pressure control of the roll bender are performed.

(Problems to be Solved by the Invention) However, in actual rolling, the amount of edge drop of a hot rolled sheet changes depending on the hot rolling conditions. Therefore, conventional edge drop control has not been able to sufficiently reduce edge drops.

Furthermore, when the work roll is shifted, the edge portion becomes thicker and excessive tension is generated, which may cause cracking of the edges.

(Means for Solving the Problems) The edge drop control method in plate rolling according to the first invention involves shifting a work roll whose roll body end is tapered in the width direction of the plate to control the edge drop of the plate. In the method, the work roll shift amount is adjusted based on the difference between the edge drop of the plate before rolling and its target value and the difference between the edge drop of the plate after rolling and its target value.

Note that the tapered body end of the work roll is tapered linearly or in a curved shape such as a sine curve or a circular arc, and comes into contact with the side end of the plate. The tapered body end portion is hereinafter referred to as a tapered portion.

To control edge drop, it must be properly quantified. Therefore, the edge drop D is defined by the two values Dl and D2 expressed by equation (1) at positions a and b, respectively, from the side edge of the plate toward the center of the plate.

D 2 = h c h b Here, ha, hb, and hc are plate thicknesses at positions a, b, and C, respectively, from the plate side edge toward the plate center, and a<b<c. These distances a, b and C are chosen empirically to adequately represent the edge drop D.

Using the edge drop defined above, the work roll shift amount SII is generally expressed as a function of the edge drop Do of the plate before rolling and the edge drop D after rolling.
-(2) Alternatively, the amount of change is Δ5II=fs (ΔDo, ΔD) ・(3
). Here, the work roll shift amount S- is the distance from the taper start point of the work roll to the plate side end. In addition, the effect of FW on edge drop D is S1
Generally smaller than 1. Here, ΔDO is the difference between the actual edge drop and the standard edge drop before rolling, and ΔD is the difference between the target edge drop after rolling and the edge drop of the rolled plate.

The above equations (2) and (3) are determined in advance by experiment or numerical analysis on an actual machine. Furthermore, the accuracy of these equations (2) and (3) can be improved through learning.

The edge drop of the plate before or after rolling is measured by, for example, a crown meter placed, for example, immediately before or after the rolling mill. The work roll shift amount SW is set by checking the board side end position using a board width gauge or the like, and shifting the work roll so that the start point of the roll taper is located at a distance SW from the board side end position.

The edge drop control method in plate rolling according to the second invention performs tension control at the edge of the plate in addition to the edge drop control of the first invention.

The tension at the edge of the plate changes according to the change in work roll shift amount ΔSw and the change in work roll bending force ΔFW, and the amount of change in tension at the edge of the plate ΔΔ is generally expressed by the following equation (4), ΔA”fA (ΔS11.ΔF)...
・(4) becomes. Note that since the plate tension depends on the plate shape expressed by steepness, etc., ΔA may be treated as representing the plate edge shape instead of the plate end tension. Equation (0) is also determined in advance by experiment or numerical analysis on the actual machine.

(Function) When the edge drop DO of the plate on the entry side of the rolling mill or the edge drop D after rolling is large, the work roll shift M S I+ is adjusted so that the contact length of the tapered part of the work roll becomes larger. .

As a result, the rolling reduction at the edge of the plate becomes smaller, so the edge drop D of the rolled plate decreases.

Also, - edge drop D of the plate rolled as above.
When the work roll shift amount Sw is adjusted to reduce the amount of work roll shift amount Sw, the tension generated at the edge of the plate during rolling tends to increase. When the work roll shift amount S11 is adjusted as described above, the work roll bender force F- is adjusted to prevent the tension from becoming excessive. This lowers the tension at the edge of the plate and prevents edge cracks from occurring.

(Embodiment) Embodiment of the first invention FIG. 1 shows an example of a cold rolling mill in which this invention is implemented.

The cold rolling mill 5 is a six-high rolling mill consisting of a work roll 6, an intermediate roll 7, and a backup roll 8. The work roll 6 has a tapered portion 6a at the end of the roll body, and is displaced in the roll axial direction by the work roll shift 13. Further, a work roll bender 11, an intermediate roll shift 14, and a coolant supply device 16 are provided as shape control means. On the inlet side of the cold rolling mill 5, there is an edge drop detector 18 for measuring the edge drop of the hot rolled coil l being rolled, and on the outlet side there is an edge drop detector 18 for measuring the edge drop of the rolled plate. 20 are arranged. An X-ray crown meter or a multi-beam crown meter is used as the inlet edge drop detector 18 and the outlet edge drop detector 20. Further, a load cell 22 for detecting rolling load P is arranged in the rolling device (not shown). The cold rolling 4a5 is controlled by a control computer and a controller (both not shown).

FIG. 2 is a drawing explaining the definition of edge drop.

In this embodiment, edge drops D1 and D2 are defined as follows.

That is, in the above formula (1), a = 15 mm,
b = 25 + * m, c = 50 mm.

In the edge drop control method of this embodiment, edge drops are detected at the entrance and exit sides of the rolling mill. Then, the work roll shift amount is feedforward controlled based on the detected entrance plate edge drop, and the work roll shift amount is feedback controlled based on the exit side plate edge drop.

In the above device, the cooling conditions of the work roll 6 by the coolant supply device 18 and the shift amount S of the intermediate roll 7
is preset according to the rolling conditions.

The amount of change in the edge drop of the input side plate ΔS and the amount of change in the edge drop of the exit side plate! ! The work roll shift correction amount Δ due to 0 is given by the following equation (6).

ΔSw=, [1s・ΔD+Jlc・Δdano −(
8) Here, in each of the above equations, the subscript W represents the work side, D represents the drive side, - represents a row vector, and ~ represents a matrix, respectively. In addition, the influence coefficient danS and the influence coefficient danC represent the degree of influence that the edge drop change amounts Δp and Δs0 have on the work roll shift itSw, respectively, and were determined by an experiment on an actual machine or by numerical analysis. Find it and store it in the control computer.

FIG. 3 is a block diagram of the control system of this embodiment.

As shown in FIG. 3, the amount of change in edge drop of the rolled plate ΔD is determined by two factors: the amount of change in work roll shift ΔT-5 and the amount of change in edge drop of the incoming plate ΔDo. The influence of these variations ΔSt+ and Δno on the edge drop variation Δp of the rolled plate is expressed by the influence coefficients shown in equations (7) and (8). and ΔS.

to these influence coefficients. and 8S can be determined in advance by experiment or numerical analysis on an actual machine.

In addition, the characteristics of the detector, regulator, and output device in the block diagram in Section 2 are as follows.

Crown meter: (j=1.2) Work roll shift system: Control law: Gc = Gc J-, Gc = Kc -
(11) Steady-state deviation compensator: ...(12) The plate edge drop at the entrance side of the rolling mill is caused by the time τ1 prior to rolling, and the plate edge drop at the exit side of the rolling mill is determined by the period from rolling to shape detection. Each is detected by the crown meter after a delay of time τ2. Based on the detected plate edge drops at the entrance and exit sides of the rolling mill,
The influence coefficient J expressed by equations (6e) and (6d)
Using lc and dan, the work roll shift correction amount corresponding to each edge drop is determined. These correction amounts are added together as shown in equation (6) above,
The work roll shift correction amount ΔSw is determined. The work roll shift correction amount Δ calculated by the calculation is output to the work roll shift via a steady-state error compensator and a control law. Note that the output of the work roll shift is feedback-controlled.

Embodiment of the Second Invention In this embodiment, control of the root end tension is added to the embodiment of the first invention described above.

The work roll shift correction amount ΔDan- based on the edge drop change amount ΔDan of the entry side plate and the edge drop change amount Do of the exit side plate is calculated by the above equation (3) as in the embodiment of the first invention.
is given by

When the work roll shift amount on the work side changes by ΔSww, the work roll shift amount on the drive side changes by Δ31, and the work roll bender force changes by ΔFW, the tension Δe at the plate end becomes ΔAe as expressed by the following equation (14). only changes.

ΔAe=AsPCΔ5jljl+ΔS IID) +
A FeΔFW...(14) Here, Ase and AFe are influence coefficients, and generally AB=aBR+β-nS + γan-(+4a
)αllβlnIγln: constant m=s, F n=1.2 where R is the work roll radius and S is the intermediate roll shift position. Note that when no intermediate roll shift is used, S=0.

In equation (10), if we set ΔΔe-0 (i.e., even if the work roll shift Ml: S and the work roll bending force FW change, the tension at the plate end maintains the required value), we get 4F. ′=Dan11 “Kito...(15
) is obtained. Here it is.

FIG. 4 is a block diagram of the control system of this embodiment.

As shown in Fig. 4, the amount of change in the edge drop of the rolled plate Δdan is determined by three factors: the amount of change in the work roll shift ΔSW, the amount of change in the edge drop of the entrance plate Δno, and the amount of change in the work roll bender force ΔFw. It's decided. Among these variations, the influence of Δdan- and Δno on the edge drop variation Δ of the rolled plate is expressed by the influence coefficients AC and 8S shown in equations (7) and (8) above, respectively. Also, the amount of change in work roll bending force Δ
The influence of FII on the edge drop change amount Δ of the rolled plate is expressed by the influence coefficient B shown in the following equation (16).

The influence coefficient f3 can also be determined in advance through experiments or numerical analysis on an actual machine.

In addition, the control law and the characteristics of the work roll bender system in the block diagram shown in Section 2 are as follows.

Control law: Here, the letter S stands for work roll shift, and the letter W stands for work roll bender.

Work roll bender system: In the above control system, the work roll shift correction amount Δdan-
The procedure for determining and outputting this to the work roll shift is the same as in the first embodiment.

In this embodiment, further, based on the output of the work roll shift, the correction amount ΔFW of the work roll bender force is determined using the 1-formula (15) and is output to the work roll bender. Note that the output of the work roll bender is controlled by feedback.

Here, a specific example of the edge drop of the plate obtained by the method of this example will be explained. The rolling equipment was a 6-stand tandem cold rolling mill, and the edge drop was measured on the exit side of the first stand.

The specifications and rolling conditions of the rolling stand are as follows.

Work roll diameter: 350s+w Body length: 2020 layers Intermediate roll diameter 2600 layers Body length: 2020m Backup roll diameter: 1300mm Body length: 2020mm Plate size: Plate thickness 2.7mm + 1.89mm, plate width 1200
+US rolling rate = 3oz Rolling load: 890
Ton Zhang crab front 13 kg/mm2 rear 3 kg
/mm2 Under the above conditions, when the work roll shift was set by the conventional method, the edge drop of the plate on the exit side of the rolling mill varied greatly from coil to coil, and in the case of brittle materials such as electrical steel sheets, plate breakage occurred frequently. On the other hand,
According to the method of this example, the variation in the edge drop of the plate on the exit side of the rolling machine between coils was significantly reduced, and there was no plate breakage even in brittle materials such as electrical steel sheets.

(Effects of the Invention) According to the present invention, since the work roll shift amount is adjusted based on the edge drop of the plate before and after rolling, the variation in edge drop between coils is significantly reduced. Furthermore, since the work roll bender was also adjusted in addition to adjusting the work roll shift amount, there was no plate breakage.

[Brief explanation of drawings]

Figure 1 shows an example of a cold rolling mill in which this IJ is carried out, and is a schematic perspective view of the rolling mill. Figure 2 is a drawing explaining the definition of edge drop, and Figures 3 and 4 are FIG. 1 is a block diagram of a control system, each showing an embodiment of the present invention. 1.2...Rolled plate, 6...Work roll, 8a...
・Part of the taper of the work roll, 7...Intermediate roll, 8
... Bank up roll, 11... Work roll bender, 13... Work roll shift, 14...
・Intermediate port shift, 16... Roll coolant supply device, 18... Plate edge drop detector on the rolling mill inlet side, 20... Plate edge drop detector on the rolling mill exit side, 2
2...Load cell.

Claims (2)

[Claims] (1) In a method of controlling the edge drop of a plate by shifting a work roll with a tapered roll body end in the width direction of the plate, the difference between the edge drop of the plate before rolling and its target value, and the rolling An edge drop control method in plate rolling, characterized by adjusting a work roll shift amount based on the difference between the subsequent edge drop of the plate and its target value. (2) In a method of controlling the edge drop of a plate by shifting a work roll with a tapered roll body end in the width direction of the plate, the difference between the edge drop of the plate before rolling and its target value, and the rolling The work roll shift amount is adjusted based on the difference between the edge drop of the subsequent plate and its target value, and the work roll bending force is adjusted so that the tension at the edge of the plate is at an appropriate value. Edge drop control method in plate rolling.