JPS62244506A - Setting up method for edge drop control of sheet rolling - Google Patents

Abstract

PURPOSE:To prevent the variance of an edge drop and to improve the yield of a product by setting the shift quantity and bender force of work rolls in accordance with the width and edge drop of a sheet prior to rolling. CONSTITUTION:A tapered part 6a is disposed to the roll barrel end of the work roll 6. A work roll bender 11, an intermediate roll shift 14, and a coolant supplying device 16 are respectively disposed as shape control means. A detector 18 for the edge drop and width of a hot rolled coil 1 is installed. The shift quantity and bender force of the roll 6 are so determined as to minimize the evaluation function of the sheet end tension and edge drop quantity expressed by the prescribed equation based on the sheet width and edge drop prior to rolling by such mechanisms. The coolant supplying device 16 is further controlled. The variance of the edge drop is prevented and the yield of the product is improved by the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a setup method for edge drop control in plate rolling.

(Prior Art) It is desirable that a 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. 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 amount of 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, a shift star in the sheet width direction of a pair of tapered work rolls is adjusted in accordance with the sheet width. Also, JP-A-Sho [1-
In the technique disclosed in Japanese Patent No. 12213, the edge drop amount measurement 41et of the steel plate from the plate thickness gauge at the exit side of the final stand is compared with a target edge drop amount setting value, and based on this comparison calculation value, the work roll is Shift control and roll venter operating pressure control.

In addition, many plate shape control methods have been proposed and implemented. The plate shape is mainly controlled by adjusting the bending deflection of the roll or the crown. As a means to mechanically adjust roll bending deflection or crown, backup roll venter, intermediate roll bender, work roll bender, shift amount of intermediate roll in plate width direction, backup bearing division adjustment in plate width direction, or roll internal pressure There are adjustments etc. Further, as means for thermally adjusting the roll crown, there are means such as roll cooling water adjustment and roll local heating. The control means for the bending deflection or crown of these rolls is based on the material plate (e.g., hot-rolled coil) and the rolling conditions before the start of rolling.
is preset. Further, during steady rolling, it is common to detect the plate shape on the exit side of the rolling mill and perform feedback control of roll bending deflection or roll crown control means.

2. As a method of detecting the plate shape on the exit side of the rolling machine during steady rolling and feedback controlling the plate shape, there is a technique disclosed in, for example, Japanese Patent Laid-Open No. 8O-tB804. In this method, the roll bender force and intermediate roll position are adjusted based on the shape pattern detected by a shape detector provided on the exit side of the rolling mill.

In these edge drop control and shape control, the optimum setting value of the work roll shift amount is usually determined in advance based on the rolling conditions, and the work roll shift acid is set to the optimum setting value during rolling.

(Problem to be solved by the invention) However, in actual rolling, the edge drop amount of a hot rolled sheet changes depending on the hot rolling conditions, and the width of a sheet that is not trimmed is slightly more irregular than the nominal value. ing. Therefore, it has not been possible to sufficiently reduce edge drops with the conventional edge drop control setup. Furthermore, when the work roll is shifted, the edge portion becomes thick and excessive tension is generated, which may cause cracking of the edges.

Furthermore, when the work roll shift amount and the pender force are corrected in the setup of edge drop control, there is also the problem that the plate shape collapses.

(Means for Solving the Problems) A set-up method for edge drop control in plate rolling according to the first invention shifts a work roll having a tapered roll body end in the width direction of the plate to control the edge drop of the plate. In this method, the work roll shift amount and work roll bender force are set based on the width and edge drop of the sheet before rolling. 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. 2. The tapered end of the body is hereinafter referred to as the taper part.

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.

D2 =hc hb Here, ha, hb, and he are the 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.

Edge drop D defined as above is work roll shift iLsw, work roll bending force FW
and the edge drop of the plate before rolling I) in general as a function of 0 D = fo (SII, Fw, Do) −
It is expressed as (2). Here, the work roll shift amount S
- is the distance from the taper start point of the work roll to the plate side edge. In addition, the effect of work roll bender curve rw on edge drop D is work roll shift) , , j,
Generally smaller than tS-.

In addition, the tension A at the plate end during rolling is the work roll shift amount S
−, work roll bender force Fw, intermediate roll bender force Fl+edge drop Do of the plate before rolling, and intermediate roll shift amount S as a function of A=fA(SII, F@, F+, Do, S) −(
3). Here, the effects of the intermediate roll bending force F1 and the intermediate roll shift amount S on the tension A are generally smaller than those of the work roll shift -N:SW and the work roll bending force FW. The edge drop Do of the plate before rolling is measured, for example, by a crown meter placed just before the rolling mill. Note that since the plate tension depends on the plate shape expressed by steepness, etc., 8 may be treated as representing the plate edge shape instead of the plate end tension.

Then, to set the edge drop to an optimal value, J = f J ((D - D) 2. (Δ - A) 2)
...The work roll shift is performed so that the evaluation function J of the edge drop amount and plate edge tension expressed by (4) is minimized:! Determine jt S v and work role bender capacity F-. D and A are each target values. To set the work roll shift amount S11, check the plate side edge position using a plate width meter placed upstream of the rolling mill, and set the start point of the roll taper at a distance equal to the work roll shift amount Sw from the plate side edge position. Shift the work roll so that it is positioned.

The above equations (1) to (3) are determined in advance by experiment or numerical analysis on an actual machine. Furthermore, the accuracy of these equations (1) to (3) can be improved through learning.

The cell i-up method for edge drop control in plate rolling according to the second invention corrects the shape of the plate in addition to the method of the first invention. The modification of the shape of the plate is the change in the shape of the plate ΔA
The flow rate distribution Q of the roll coolant in the plate width direction is adjusted based on the following. The shape of the plate is determined by the change in roll shift amount ΔSI+
and changes in work roll bending force ΔFM, and is generally expressed by the following equation (5).

ΔΔ”fA(ΔSW+ΔFw)...(5
) Also, due to the change ΔA in the plate shape, the change ΔQ in the flow rate distribution of the roll coolant becomes ΔQ=fo(ΔA) (6). Equations (5) and (6) are also determined in advance by experiment or numerical analysis on an actual machine.

(Function) When the edge drop no of the plate on the entry side of the rolling mill is large, the work roll shift amount S- is set so that the contact length of the tapered part of the work roll becomes larger. As a result,
The edge drop D of the rolled plate is reduced because the reduction at the edge of the plate is smaller. Note that when setting the work roll shift amount SW, the magnitude of the bender force Fw is also set at the same time so that the tension at the plate end does not become excessive.

When the work roll shift 41 S w and the bender force FW are set to reduce the edge drop D as described above, the rolled plate generally tends to undergo medium elongation. To prevent this from elongating.

Intermediate roll shift amount Sl and intermediate roll bending force F
At the same time as setting +, the flow rate distribution Q of the roll coolant in the plate width direction is adjusted based on the prediction result of the plate shape so that the plate shape is good over the width of the sheet metal. In addition, as a method of preventing this elongation, only the flow rate distribution Q of the roll coolant in the plate width direction may be adjusted. By adjusting the flow rate distribution Q of the roll coolant in the sheet width direction, the thermal strain distribution of the work roll is changed and the work roll crown is corrected.

As a result, the plate is rolled to a uniform thickness and shape throughout.

(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 a work roll shifter 13. Further, a work roll bender 11. is used as a shape control means. (intermediate roll shift) 14 and a coolant supply device 18. On the entry side of the cold rolling mill 5, an edge drop detector 18 and a strip width meter 18 are arranged to measure the edge drop and strip width of the hot rolled coil 1 to be rolled. An X-ray type crown meter, an optical type plate width meter, or a multi-beam type crown meter (simultaneous measurement of the crown and plate width) is used as the plate edge drop meter 18 and plate width meter 18 on the entry side. Further, a load cell 22 for detecting rolling load P is arranged in the rolling device (not shown). The cold rolling mill 5 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 C2 are defined as follows.

C2 = h5o - h25 That is, in the above formula (1), a = 15 mm,
b = 25 + * m, c = 50 mm.

FIG. 3 is a flowchart showing the setup procedure.

As shown in FIG. 3, first, the intermediate roll bender force Fl and the shift amount S of the intermediate roll 7 are set in advance based on the radius R of the work roll 6 and the rolling load P. At this time, if the intermediate roll 7 is not shifted (if the rolling mill is a 4-fold rolling mill or a simple 6-fold rolling mill), shift 1. S
= O. Further, the work roll shift amount SW and the pender force FW for reducing the target plate edge tension and the target edge drop edge drop D are determined as follows.

The work roll shift amount on the work side is 5 Wjl, the work roll shift amount on the drive side is SWO, and the work roll bending force is 50 and 15 III from the edge of the FW original plate.
The edge drop amount between 11 and 001, and the edge drop amount between 50 and 25 mm from the edge of the original plate as D.
o2, the edge drop on the work side of the rolled plate DIi1. D2W and drive side edge drop DID, C2[+ are expressed as follows.

D +11=A s+S ww+A r+F+A
o+D o1+ CID +o=As+SWn+Az
Fy +ADIDO1+CID 211= A SO3
ww + A F2F w + A C2D 02+ C
2D 2a= A S2S wo+ A r2F w
10A C2D 02+ C2...(8) Here, C1 and C1 are learning terms, ASl, AFllA
o+, A S2. A F2. A C2 is an influence coefficient.

In addition, the work roll shift amount on the work side is 5jlW,
Drive side work roll shift amount 5IID, work roll bender force FW and intermediate roll bender force F
The plate edge tension when l is set as above is expressed by the following equation (9).

Ae =Ase(Sww+Swo) +AFeFII+
A IeF I + A +eD o++ A 2e
D 02+ A per + A Oe
++ (9) Here, Ase, Are, A+e,
A+e, A2e, APe.

AOe is the influence coefficient, generally AH= a @nR+β*nS + ”Y sn
-(8a) α-β・β-kai n・γln: constant m=s, F, D, 1, 2. P, 0 n=1.2. It is shown in the form of e.

The influence coefficients in the above equations (8), (9), and (9a) are all determined in advance by experiment or numerical analysis for the actual machine, and are stored in the control computer.

Edge drop amount Dlil determined as above
”'020, plate edge tension Δe and their target values D 1
．． Evaluation function J of the edge drop amount and plate edge tension expressed by the linear equation (10) based on 02+A l+ and the edge drop amounts DO1 and DO2 at the entrance side of the rolling mill.
The work roll shift amount on the work side is 5WII, and the work roll shift amount on the drive side is 5WII so that
WO1 and work role vendor FW are determined.

J=w+(D+-D+)2+W2(C2-02)2+W
3(Ae −Ae )2 −C1o
) In the above equation, w1 to w3 are weighting coefficients, which are determined empirically based on operational results.

Here, a specific example of the edge drop of the plate obtained in Example V: will be described. 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: 350mm Body length: 2020mm Intermediate roll diameter: 60h layer Body Lc: 202hm Backup roll diameter: 1300mm Body length: 2020mm Plate size: Plate thickness 2.7 + st + 1.89 mm, plate + [120
0mm rolling reduction rate: 3oz Rolling load: 890
Ton Zhang crab front 13 kg/IIIm? 3k rear
g/ms? Under the above conditions, when the work roll shift is set up using the conventional method, the edge drop of the plate on the exit side of the rolling mill varies greatly from coil to coil.
For brittle materials such as electrical steel sheets, plate breakage occurred frequently. On the other hand, according to the method of this embodiment, the edge drop of the plate on the exit side of the rolling machine has a significantly reduced variation between coils.
Even with brittle materials such as electromagnetic steel sheets, there was no plate breakage.

Embodiment of the Second Invention In this embodiment, in addition to the method of the second embodiment of the first invention, the rolling mill shown in FIG. 1 is set up in consideration of sheet shape modification. FIG. 4 is a flowchart showing the setup procedure.

As shown in FIG. 4, first, the plate shape set-up conditions are determined based on the radius R of the work roll 6 and the rolling load P, that is, the bending force Fl and sea y of the intermediate roll 7.
S, roll coolant flow rate distribution in plate width direction Q C, Q
Q, Qe and Qo are set in advance so that the plate shape is flat. Here, the subscript C is near the center of the plate width,
q indicates the vicinity of a part of the board width quarter, e indicates the vicinity of the board end, and 0 indicates the outside of the board path. Also, set 〇 to 1” mark edge tension and 1” mark edge drop DI, D 2.

Work roll shift (SW) 41 SW and bender force FW for reducing edge drop D are determined as follows.

The work roll shift amount on the work side is 5 Will, the work roll shift amount on the drive side is 5 jlD, the work roll bending force is F-the edge drop amount between 50 and 15 lin from the edge of the original plate is DOI, and DO the edge drop amount between 50 and 25+wm from the board edge.
', then the work side edge drop DIW, D2υ and drive side edge drop DID, D2D of the rolled plate are expressed as follows.

D +w= A s+S iv1A [IF support +A
o+D o+approval +CID+o=As+Swo+AzF
w +Ao+Do+o +C+D2W Engineering A S2S w
w+ A F2F w + A D2D 0211 +
C2D 2o= A S2S wo+ A F2F
II+ A D2D 02D + C2...(11) Here, CI and CI are learning terms, As++Ar+.

A o+, A S7. A r2. A o2 is the influence coefficient. Further, subscripts W and D such as Do+w and Do+o represent the work side and the drive side, respectively.

In addition, the work roll shift amount on the work side is 5jll+
, drive side work roll shift amount S ljD,
When the work roll bending force F- and the intermediate roll bending force Fl are set as described above, the plate edge tension Ae is expressed by the following equation (12).

Ae =Ase(Sww+Swo) +AreFw+A
+eFI+A+e(Do+w +Do+o)+A2e
(Do2w +DO2D) +ApeP+Aoe
...(12) Here, ASe,
Ale, AIe, Ale, A2e+ Ape.

AOI! is the influence coefficient, generally A 1n = αsnR + β lns + γl
... (12a) α-n, β-kiri n, γ-n: constant m=S, F, D, l, 2. P, 0 n=1.2. It is shown in the form of e.

The influence coefficients in the above equations (11), (12), and (12a) are all determined in advance by experiment or numerical analysis for the actual machine, and are stored in the control computer.

Edge drop amount Dljl obtained as above
"D2D, plate edge tension Δe and their target values D 11
021A Based on el and the edge drop amounts DO1 and DO2 on the entry side of the rolling mill, the work roll shift f on the work side is adjusted so that the evaluation function J of the edge drop amount and plate edge tension expressed by the following equation (13) is minimized.
f15ww, drive side work roll shift amount 5
jlD, and the work roll bending force F- are determined.

+W3(Δ.-Δe)2, (13) In the above equation, W1 to W3 are weighting coefficients.

When the work roll shift (mSy) and the pender force FW are adjusted to reduce the edge drop D as described above, the shape of the rolled sheet changes in response to this adjustment. Therefore, the change in work roll shift l-I ΔSt+
Then, the shape change ΔA of the plate due to the change ΔF− in the work roll bender force is determined, and the flow rate distribution Q of the roll coolant in the plate width direction is adjusted based on this shape change ΔΔ.

In order to modify the plate shape by adjusting the flow rate distribution Q of the roll coolant in the plate width direction, it is necessary to quantitatively represent the shape such as the middle elongation and edge elongation. Therefore, in this embodiment, shape evaluation functions A2 and A4 are defined using the following equation (14) using steepness distribution.

Here, W and O in parentheses indicate the distance between the side edge of the board and the center of the board measured from the center of the board, and a is 25~'50
It represents.

When shape evaluation functions A2 and A4 are defined in this way,
Change in plate shape ΔA due to change in work roll shift position ΔSW and change in work roll bender force ΔF++
2. ΔA4. and roll coolant correction amount ΔQe,
ΔQ is expressed by the following equations (15) and (16), respectively.

ΔΔ2=β11ΔF+++β12(Δ5jljl+ΔS
wo) ΔΔ4 = β21ΔF++ +β22(ΔSW
W+ΔSwo) (15) Here, β11 to β22 are influence coefficients.

ΔQq=BqΔΔ4 Here, β11 to β22, BC and Bq are influence coefficients.

In this way, the roll coolant correction amount ΔQe.

Once ΔQq is determined, the roll coolant flow rate is set as follows.

Qq=Qqo+ΔQ.

Here, Qpo and Qqo represent the roll coolant flow rate before correction.

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: 350cm Body length: 202h Intermediate roll diameter: 1300+1cm Body length: 202h Recommended back-up roll diameter: 1300mm Body length: 2020II11 Board size: Board thickness 2.7m → 1.89mm, board width 120Qm
m Reduction rate = 3oz Rolling load: [Oton
Zhang crab front 13 kg/m+m2 rear 3 kg/mm
2 Under the above conditions, when the work roll shift amount 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 plate breakage occurred frequently in brittle materials such as electrical steel sheets. On the other hand, according to the method of this embodiment, the edge drop of the plate on the exit side of the rolling machine greatly reduces the variation between coils, and there is no plate breakage even in brittle materials such as electrical steel sheets. Ta. Also,
The plate shape was good.

(Effects of the Invention) According to the present invention, since the work roll shift amount and venter force are set based on the edge drop of the plate before rolling, the variation in edge drop between coils is significantly reduced. Additionally, there were no board breaks.

Furthermore, since the work roll crown is corrected by adjusting the flow rate distribution of the work roll coolant in the plate width direction in addition to the settings described in ``2'', defects in the plate shape are eliminated and the yield is improved. Furthermore, there is no need to decelerate the rolling line for shape correction, reducing acceleration/deceleration time and improving productivity.

[Brief explanation of drawings]

Fig. 1 shows an example of a cold rolling mill in which the present invention is implemented, and is a schematic perspective view of the rolling mill, Fig. 2 is a drawing explaining the definition of edge drop, and Figs. 3 and 4 are respectively 3 is a flowchart showing the setup procedure of the present invention. 1.2... Rolled plate, 6... Work roll, 6a...
・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 roll shift, 16... Roll coolant supply device, 18... Plate crown detector on the rolling machine entry side, 22.
...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 work roll shift amount and the edge drop are determined based on the width and edge drop of the plate before rolling. A setup method for edge drop control in plate rolling, characterized by setting work roll bender force. (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 amount of work roll shift and A setup method for edge drop control in plate rolling, characterized by setting the work roll bender force and setting the flow rate distribution of roll coolant in the width direction of the plate so that the plate shape in the width direction is substantially flat. .