JP2756871B2 - Setup control method in rolling of single crown metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a set-up control method for rolling a single crown metal strip having a gradually decreasing thickness from one side end to the other side end of a sheet width into a predetermined sectional shape. It is.

[0002]

2. Description of the Related Art Rolling of metal strips has long been generally performed under symmetric conditions (drive side and operation side) for a long time. In recent years, however, it has become necessary to perform rolling under asymmetric conditions under the following circumstances. I have. The situation is that a wide metal strip (hereinafter sometimes referred to as “material”) that has been rolled to an intermediate thickness is slit in the longitudinal direction to form a narrow material, which is further rolled. It is increasing. Generally, the thickness of the rolled material is gradually reduced almost symmetrically toward both sides even if the center portion of the width is the thickest, and in the above slit, the slit is often slit right and left in the middle of the width of the wide material, The slit material thus obtained has a plate thickness distribution of a single crown in which the plate thickness gradually decreases from the side end of the plate width to the other side end. When such a single crown material is rolled under symmetrical conditions, so-called single elongation in which the elongation on the thicker side is large and the elongation on the thinner side is small tends to occur. Therefore, when such a single crown material is rolled, asymmetrical rolling conditions are required so that the cross-sectional shape does not become one-sided, that is, the cross-sectional shape is similar to that before rolling.

[0003] Such a rolling situation will be described with reference to the drawings. FIG. 11 is an explanatory view showing a rolling state by a six-high rolling mill. As shown in FIG. 11, the asymmetrical rolling conditions for preventing the occurrence of the one-sided elongation shape due to the rolling include bending forces Wb and Wb 'between the operation side and the drive side of the work roll 1 and the operation side and the drive side of the intermediate roll 2 as shown in FIG. Bending force Ib,
Ib ', the rolling forces P and P' applied to the operation side and the driving side of the backup roll 3, the shift position δ of the upper and lower intermediate rolls 2,
It is adopted to make δ 'different from each other (this method is referred to as asymmetrical shape control means), thereby changing the deflection and inclination of the work roll 1 so that the elongation ratio between the operation side and the drive side is equal. Thus, the metal strip 4 is rolled by controlling the difference between the above rolling conditions.

When empirically setting the above-mentioned difference between the operating side and the driving side for the rolling conditions of each roll,
The control accuracy was poor, and it was difficult to prevent the occurrence of one-sided elongation. Therefore, a work detector between the operation side and the drive side that is optimal for correcting the asymmetric component of the shape of the rolling mill exit side from the shape information of the metal strip after rolling by installing a shape detector on the rolling mill exit side Japanese Patent Application Laid-Open No. 56-59525 discloses a method of calculating the bending force difference dWb of the roll 1 and the rolling force difference dP applied to the backup roll 3 to control the shape. The asymmetric shape control method using this shape detector has a great effect on correcting the one-sided extension shape. However, in the rolling of the single crown material, the thickness distribution on the entry side of the rolling mill (that is, before the rolling) must be sufficiently considered in spite of the necessity of sufficiently considering the thickness distribution on the entry side. The relationship between the roll and the rolling mill exit side (that is, after rolling) has not been clarified. Therefore, during setup (setting of conditions for starting the rolling), the difference between the driving side and the operating side of the rolling conditions of each roll is determined. That is, the bending force difference d of the work roll 1
Wb, the bending force difference dIb of the intermediate roll 2, the rolling force difference dP applied to the backup roll 3, and the shift position difference dδ of the upper and lower intermediate rolls 2 (hereinafter, these dW
At present, b, dIb, dP, and dδ are collectively referred to as an asymmetric shape control term). For this reason, there was a problem that the elongation of the metal strip 4 became remarkable in the initial stage of rolling.

[0005]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned problems of the prior art, and performs setup control in which the thickness distribution in the width direction at the entry side of the rolling mill is sufficiently taken into consideration so that the stripping can be started from the start of rolling. It is an object to enable rolling without elongation.

[0006]

The inventors of the present invention have conducted various studies to establish a method for controlling the set-up of a single crown material in consideration of the thickness distribution in the width direction at the entry side of the rolling mill. Regarding the elongation and the thickness of each of the plate-side end portions and the quarter portions on both sides that are equidistant from the center of the plate width toward the operation side and the drive side, between the plate-side ends on the rolling mill exit side. Elongation difference Δεe and the elongation difference Δqq between the quarters, and the thickness difference ΔHe between the plate-side ends on the entry side of the rolling mill and the thickness difference ΔHq between the quarters, The present inventors have completed the present invention by finding that a linear relationship holds between them.

That is, according to the present invention, the elongation differences Δεe and △
each said plate thickness difference εq △ He and △ Hq and using the fact that a linear relationship, △ .epsilon.e and △ Ipushironq each target value △ .epsilon.e ₀ and △ εq ₀ become as asymmetric control term group This is a setup control method that rationally derives and sets a control amount for any two of dWb, dIb, dP, and dδ, and is configured as follows.

A first aspect of the present invention is to provide a single-crown metal strip having an asymmetric shape on both sides in which the sheet thickness gradually decreases from one side end to the other side end of the sheet width, and a multi-high rolling mill of four or more rolling mills. The bending force difference dWb of the work roll between the operating side and the driving side is used, and the bending force difference dIb of the intermediate roll as well.
Similarly, in the setup control when rolling to a predetermined cross-sectional shape by controlling a part or all of the asymmetric shape control term group consisting of the rolling force difference dP of the backup roll and the shift position difference dδ of the upper and lower intermediate rolls, The elongation difference △ εe between the plate-side ends and the quarter Any two control terms dW ₁ ′ and dW ₂ ′ are selected from the group of asymmetric shape control terms so that the elongation difference △ εq between the parts becomes the target values △ εe ₀ and △ εq ₀ respectively. The control amounts dW ₁ and dW ₂ are calculated by the following equations.

(Equation 4) In the second aspect of the present invention, two asymmetrical shape control terms dW ₁ ′ and dW ₂ arbitrarily selected in the first aspect of the present invention. In addition to the above two asymmetric shape control terms, another asymmetric shape control term dW ₃ ′ other than the above two asymmetric shape control terms is arbitrarily selected and set to an arbitrary control amount dW ₃ to control the two asymmetric shape control terms. The quantities dW ₁ and dW ₂ are given by the following equations:

(Equation 5) A third aspect of the present invention is a setup control method for rolling a single crown metal strip, wherein the two asymmetric shape control terms dW ₁ ′ and dW ₂ are arbitrarily selected in the first invention method. ′, The arbitrary control amounts dW ₃ and dW ₄ are set for the remaining two asymmetric shape control items dW ₃ ′ and dW ₄ ′, respectively, and the two control amounts dW ₁ and dW ₂ are calculated by the following equations.

(Equation 6) The present invention relates to a setup control method in rolling of a single crown metal strip, characterized by setting according to the following. △ He, △ Hq, a, b, c, d, e,
f, g, h, k, m, n, and r will be described below.

Hereinafter, a setup control method for rolling a single crown metal strip according to the present invention will be specifically described with reference to the drawings. FIG. 1 is an explanatory view of sheet thickness distribution, sheet thickness difference and elongation rate difference between the entrance side and exit side of a rolling mill in rolling of a metal strip, and FIGS. 2 to 5 show the sheet thickness differences ΔHe and ΔHq, respectively. FIGS. 6 to 9 are explanatory diagrams showing a linear relationship with each of the rate differences Δεe and Δεq, and FIGS. 6 to 9 show asymmetric shape control term groups dWb, dWI,
FIG. 10 is an explanatory view showing a linear relationship between each of dP and dδ and each of the elongation differences Δεe and Δεq. FIG. 10 shows the elongation percentage over the entire width of the plate in the example and the comparative example. FIG.

Hereinafter, a six-high rolling mill will be described as an example. First, in the present invention, as shown in FIG. 1, the operation side and the drive side (in the drawing, the thicker one is operated) than the center (width L in FIG. 1) of the metal strip on the exit side of the rolling mill. The thickness of each of the plate-side end portions and both-side quota portions that are equidistant from each other toward the sides (but not restricted to these sides) is represented by the following symbols. That is, the plate thickness at the operation-side plate side at the entry side of the rolling mill is HeW, the plate thickness at the quarter portion is HqW, the plate thickness at the drive-side plate side is HeD, and the plate thickness at the quarter portion is the same. Is HqD, the plate thickness at the operation-side plate side at the rolling mill exit side is heW, the plate thickness at the quarter portion is hqW, and the plate thickness at the drive-side plate side is heD, The thickness is hqD. In the present invention, the plate-side end portion, since the thickness of the rolled metal strip is sharply reduced on the plate-side end side from a position generally about 20 mm from the plate end,
20mm from the edge of the board. The quota part is the midpoint between the center of the plate width and the end on the plate side.

Using the above symbols, the elongation difference △ εe between the plate-side ends on the exit side of the rolling mill and the elongation difference △ εq between the quarter portions, and the thickness of each of the plate-side end and the quarter portion Consider the relationship with First, the thickness difference ΔHe between the plate side ends at the entry side of the rolling mill and the thickness difference ΔHq between the quarter portions are expressed by the following equations. ΔHe = HeW−HeD ‥‥ (1) ΔHq = HqW−HqD ‥‥ (2) The elongation differences Δεe and Δεq are represented by the following equations. Δεe = −Δln (heW / HeW) −ln (heD / HeD)｝ ‥‥ (3) Δεq = −ζ ｛ln (hqW / HqW) −ln (hqd / Hqd)｝ ‥‥ (4) (Here, ζ is the ratio of the difference in strain in the rolling direction and the difference in strain in the thickness direction between the operating side and the driving side.)

Equations (3) and (4) are derived as follows. That is, assuming that the strain in the rolling direction is ε, the strain in the plate thickness direction is ε ′, and the strain in the plate width direction is ε ″, the rolling process is one type of plastic working. Ε + ε ′ + ε ″ = 0 ‥‥ (5) Assuming that the strain differences in the rolling direction, sheet thickness direction and sheet width direction between the operating side and the driving side are △ ε, △ ε ′ and △ ε ″, respectively. Similarly, the following relationship holds: Δε + △ ε ′ + △ ε ″ = 0 ＝ (6) Here, since the sheet width hardly changes before and after rolling, the difference in strain in the sheet width direction is not considered. In this case, △ ε = − △ ε ″
However, when the ratio of the strain difference between the rolling direction and the thickness direction is set to し て in consideration of the strain difference in the sheet width direction, Δε = −ζ △ ε ″ ‥‥ (7). Is represented by the general expression ln (h / H) in true distortion (logarithmic distortion), and when combined with the relationship of Expression (7), Expressions (3) and (4) are obtained.

As a result of investigations under many rolling conditions, it was found that a linear relationship is established between the elongation differences Δεe and Δεq and the plate thickness differences ΔHe and ΔHq when the asymmetric shape control means is not used. There was found. Therefore, the elongation difference △ εe
And △ εq are represented by the following equations. Δεe = a △ He + b △ Hq + k ‥‥ (8) △ εq = c △ He + d △ Hq + k ′ ‥‥ (9) where k and k ′ are constant terms

Here, the meaning of the coefficients a, b, c and d will be described with reference to FIGS. The data shown in each of the above figures and FIGS. 6 to 9 described later are data obtained by using the same six-rolling mill used in the examples described later. Assuming that 一定 Hq is constant in equation (8), △ e and △
He is in a linear relationship with He, and a is a coefficient indicating the slope of △ εe with respect to 即 ち He (ie, eεe / △ He when the coordinate axes are translated so that a straight line is placed at the origin). Also, the formula
When △ He is constant in (8), as shown in FIG.
There is a linear relationship between εe and △ Hq, and b is △
This is a coefficient indicating the slope of εe. Similarly, in the equation (9), c and d are the slopes of 示 す εq with respect to △ He and △ εq with respect to △ Hq, respectively, as shown in FIGS.
Is a coefficient indicating the slope of

In the equations (8) and (9), when the sheet thickness differences ΔHe and ΔHq are both set to 0 when the asymmetric shape control means is not used, the sheet thickness distribution on the entry side of the rolling mill becomes bilaterally symmetric. ,
The rolling mill exit side shape is also symmetrical (that is, △ εe = 0, △ εq =
0). Accordingly, the constant terms k and k 'are both 0, and the equations (8) and (9) are as follows:? E = a? He + b? Hq? (10)? E = c? He + d? Hq? (11) Become. These are collectively displayed as a matrix as follows.

(Equation 7)

Next, in the case where the metal strip is rolled without using the asymmetrical shape control means as described above, an appropriate control amount is obtained by considering the effect of using the asymmetrical shape control means. Examination of many rolling conditions shows that each of the elongation differences △ εe and △ εq is asymmetric shape control term group dW
It was found that there was a linear relationship with any of b, dIb, dP and dδ. In each example of the linear relationship, the relationship with dWb is shown in FIG. 6, and the relationship with dIb is shown in FIG.
FIG. 8 shows the relationship with dP, and FIG. 9 shows the relationship with dδ.
Respectively.

First, a description will be given of a case in which asymmetric shape control means using dW ₁ ′ and dW ₂ ′ as two control terms arbitrarily selected from the asymmetric shape control term group is used. In linear relationship established between each respectively elongation difference △ .epsilon.e and △ Ipushironq 'and dW _2' asymmetrical control term dW ₁ and the inclination of the case of the slope (the a of △ .epsilon.e for dW ₁ The same meaning) as e, △ for dW ₂
The coefficient indicating the slope of εe is f, the coefficient indicating the slope of △ Ipushironq for dW ₁ and g, the coefficient indicating the slope of △ Ipushironq for dW ₂ and h.

The effect of each asymmetric shape control means can be considered by adding. That is, assuming that the control amounts of the applied asymmetric shape control terms dW ₁ ′ and dW ₂ ′ are dW ₁ and dW ₂ , respectively, equations (11) and (12) are as follows. Δεe = a △ He + b △ Hq + edW ₁ + fdW ₂ １３ (13) Δεq = c △ He + d △ Hq + gdW ₁ + hdW ₂ １４ (14) These are collectively displayed as a matrix as follows.

(Equation 8) In the equation (15), the control equations (16) are obtained by solving the control amounts dW ₁ and dW _{2 by} setting the elongation difference △ εe and △ εq as the target values △ εe ₀ and △ εq ₀ respectively.

(Equation 9) Therefore, the coefficients a, b, c, d, e, f, g, and h are determined in advance as a function of rolling conditions such as rolling load and strip width, and
According to (16), dW ₁ and dW ₂ can be set.

Next, two asymmetric shape control terms d arbitrarily selected from the group of asymmetric shape control terms as described above.
One asymmetrical shape control term d different from W ₁ ′, dW ₂ ′
W ₃ ′ is arbitrarily selected, and a total of three asymmetric shape control terms d
The case where asymmetric shape control means based on W ₁ ′, dW ₂ ′ and dW ₃ ′ is used will be described. Based on the same concept as when using the two asymmetric shape control terms, the following equation (17) is obtained corresponding to equation (15).

(Equation 10) Here, dW ₃ is a control amount of the asymmetrical control term dW ₃ ', and k is a coefficient indicating the slope of △ .epsilon.e for dW ₃ in the linear relation shown by the the dW ₃ △ .epsilon.e, m is dW
_This is a coefficient indicating the slope of △ εq with respect to dW _{3 in the} linear relationship indicated by ₃ and △ εq.

In equation (17), the asymmetric shape control term d
If the control amount dW ₃ of W ₃ ′ is set to an arbitrary control amount, and the elongation differences △ εe and △ εq are set to the target values △ εe ₀ and △ εq _{0 respectively,} and the control amounts dW ₁ and dW ₂ are solved, A control equation (18) is obtained corresponding to the equation (16).

[Equation 11] Therefore, the two asymmetric shape control terms dW ₁ ′, dW ₂ ′
The coefficients k and m are determined in advance as a function of the rolling conditions such as the rolling load and the sheet width in the same manner as in the case of using the control means according to the formula (1).
W ₁ and dW ₂ can be set. In the above two cases, the asymmetric shape control term not used in the asymmetric shape control means is treated as a symmetric asymmetric shape control term.

Next, in addition to two asymmetric shape control terms dW ₁ ′ and dW ₂ ′ arbitrarily selected from the asymmetric shape control terms, the remaining two asymmetric shape control terms dW ₃ ′ and dW ₄ ′ are added. Each case using all the asymmetric shape control terms and three asymmetric shape control means will be described. Also in this case, the following equation (19) is obtained corresponding to equations (15) and (17) based on the same concept as in each case using the two asymmetric shape control terms and the three asymmetric shape control terms.

(Equation 12) Here, dW ₄ is a control amount of the asymmetric shape control term dW ₄ ′, n is a coefficient indicating a gradient of △ εe with respect to dW _{4 in} a linear relationship indicated by dW ₄ and △ εe, and r is dW ₄ and △ εe. ε
This is a coefficient indicating the slope of △ εq with respect to dW _{4 in the} linear relationship indicated by q.

[0022] dW _3, sets dW ₄ to arbitrary control amount, the control amount dW ₁ elongation difference △ .epsilon.e and △ Ipushironq respectively at the target value △ .epsilon.e ₀ and △ εq ₀ In Now formula (19), Solving for dW ₂ , the control equation (2) corresponds to equations (16) and (18).
0).

(Equation 13) Therefore, similarly to the case of using the control means based on the three asymmetric shape control terms, the coefficients a to h, k, and m and the coefficients n,
r can also be determined in advance as a function of rolling conditions such as rolling load and strip width, and control amounts dW ₁ and dW ₂ can be set according to equation (20).

When the predetermined cross section of the metal band after rolling is for preventing the metal band from being partially stretched, the cross sections of the metal band before and after the rolling are similar. In order to approach such a cross section as much as possible, it is preferable that the difference in elongation between the operation side and the drive side is as small as possible. Therefore, the control equations (16), (18) and (2)
In (0), by setting the control amounts dW ₁ and dW ₂ at the time of set-up so that both the target values Δεe ₀ and Δεq ₀ become 0, it is possible to perform rolling without eccentricity from the beginning of rolling.

In the above, the method of the present invention has been described for the case of using a six-high rolling mill, but the same control method is used for a rolling mill having at least a work roll and a backup roll, such as a four-high rolling mill or a cluster rolling mill. be able to. For example, when the method of the present invention is applied to a quadruple rolling mill, the control expression (16) is used because dWb, dIb, dP, and dδ have only two applicable asymmetric shape control terms, dWb and dP. The following equations using dWb and dP as the control amounts dW ₁ and dW ₂ may be used.

[Equation 14] When the multi-high rolling mill is provided with a plurality of intermediate rolls and backup rolls, dP, dIb, and dδ are respectively dP (pressure difference between the operation side and the drive side of the uppermost backup roll) and dIb (workpiece). The bending force difference between the operation side and the drive side of the intermediate roll that contacts the roll, dδ (shift position difference between the upper and lower intermediate rolls that contact the work roll), and any two to four means out of dWb, dIb, dP, and dδ Equations (16), (18), (20)
The control amounts dW ₁ and dW ₂ may be set according to the following. After performing the set-up control as described above and starting rolling, for example, by measuring the tension of each part of the metal band of the part divided into a plurality in the sheet width direction on the rolling mill exit side as described above. Rolling may be continued by a known technique such as setting a shape detector for determining the shape of the portion and rolling while correcting rolling conditions based on the obtained shape information after rolling.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment in which the method is applied to a rolling setup by a six-high rolling mill. The six-high rolling mill used was a standard work roll (135mm, 850mm, 1075mm), and intermediate rolls (300mm, 850mm, 1660mm) whose roll specifications are shown in parentheses in the order of roll diameter, roll body length, and chock distance. ) And backup rolls (630 mm, 850 mm, 1475 mm) in the same roll configuration as in FIG. 11, and the asymmetric shape control terms dWb, dIb, dP,
dδ was controllable. By using such a six-high rolling mill, a sheet width of ΔHe = 30 μm and ΔHq = 7 μm
600mm ordinary steel crown material is added to the 0.6mm
In the case of rolling under the rolling condition of 0.36 mm in exit side thickness and 170 ton rolling load, when the control amount of the asymmetric shape control term is set by the method of the present invention at the time of setup, the elongation over the entire width of the ordinary steel strip at the beginning of rolling is performed. The rate was measured.

[0026] (a) When using a two asymmetrical control term (and dW ₁ the control amount) rolling force difference dP randomly selected from among the asymmetrical control section group and the shift position difference between the upper and lower intermediate rolls Setup control was performed by asymmetric shape control means based on dδ (the control amount is dW ₂ ). Under the above rolling conditions, the values of the coefficients in the control formula (16) are as follows: a = 4.9 × 10 ⁻⁶ , b = −9.5 × 10 ⁻⁶ , c = −2.9 × 10
^-6 , d = 5.1 × 10 ^-6 , e = 1.8 × 10 ^-4 , f = 4.0 × 10 ^-6 , g
= 0.5 × 10 ⁻⁴ and h = −3.0 × 10 ⁻⁶ . Here, the target values of △ εe and qεq on the rolling mill exit side are set to △ εe ₀ = 0 and △ ε
Assuming that q ₀ = 0, dW ₁ = −0.04 (ton) and dW ₂ = −18.0 (mm) are obtained by the control equation (16), and the rolling force difference d
P and shift position difference dδ were set, setup control was performed, and rolling was started. FIG. 10A shows the elongation percentage of the ordinary steel strip in the initial stage of rolling in this case over the entire width.

(B) When three asymmetric shape control terms are used: The rolling force difference dWb (working amount thereof) of the rolling force difference dP and the shift position difference dδ, which are the asymmetric shape control terms in the case of (a) above. the use of a three asymmetrical control term plus a dW _3), was set to dW ₃ = -0.05 any value of the control amount dW ₃ (tons). Regarding the values of the respective coefficients in the control equation (18), a to h are the same as those in the case of (a), but k
= −2.0 × 10 ⁻⁴ and m = 0.1 × 10 ⁻⁴ . The target values of the elongation difference △ εe and △ εq on the exit side of the rolling mill are △ εe ₀ = 0 and △ ε
Assuming that q ₀ = 0, dW ₁ = 0.00 (ton) by control equation (18),
dW ₂ = -17.3 (mm) was obtained. Thus, the rolling force difference dP and the shift position difference dδ were set to the values of the above dW ₁ and dW ₂ , and setup control was performed to start rolling. The elongation percentage of the ordinary steel strip in the initial stage of rolling in this case is shown in FIG.

(C) When all four asymmetric shape control terms are used: The bending force difference dIb (the control amount is dW ₄ ) of the intermediate roll is added to dP, dδ and dWb in the case of (b) above. Using all four asymmetric shape control terms,
The control amount dW ₃ of dWb and the control amount dW _{4 of} dIb were set to dW ₃ = 0.03 (Ton) and dW ₄ = 0.03 (ton) of arbitrary values, respectively. The values of each coefficient of the control equation (20) are as follows:
Is the same as n, but n = −1.9 × 10 ⁻⁴ , r = −0.6 ×
It was 10 ^-4 . The control expression (20) is set assuming that the target values of the elongation difference △ εe and △ εq at the exit side of the rolling mill are △ εe ₀ = 0 and △ εq ₀ = 0.
As a result, dW ₁ = 0.02 (Ton) and dW ₂ = -17.7 (mm) are obtained. Thus, the setup control is performed by setting the rolling force difference dP and the shift position difference dδ to the values of dW ₁ and dW ₂ respectively. Rolling was started. The elongation percentage of the ordinary steel strip in the initial stage of rolling in this case is shown in FIG.

(D) For comparison, the rolling obtained by starting rolling in the same manner as in Examples (a) to (c) except that all asymmetric shape control terms were set to 0 and setup control was performed. The initial elongation rate is shown in FIG.

FIG. 10 shows that the method (a) and (b) according to the method of the present invention.
In both cases (c) and (c), the values of the elongation difference 伸 び εe and △ εq are found to be approximately 0.2 × 10 ⁻⁴ or less. On the other hand, when the asymmetric shape control means is not used, the elongation difference △ ε
It can be seen that e and △ εq have almost reached 0.7 × 10 ^-4 . When the control amount of the asymmetric shape control term is empirically set by the conventional method, the elongation difference △ εe, △
Although εq may be small, the degree is small and not constant as compared with the method of the present invention.

[0031]

As described above in detail, the set-up control method in the rolling of a one-crown metal strip according to the present invention includes the following methods: Asymmetric shape control terms dWb, dW utilizing the fact that each of ΔHq has a linear relationship.
For any two of I, dP, and dδ, the control amount is obtained by a control formula derived rationally, and set up control is performed, so that the cross section of the metal strip on the exit side of the rolling mill from the beginning of rolling. The shape can be predetermined. Therefore, by making the cross-sectional shape of the metal strip on the exit side of the rolling mill similar to that on the entry side, a one-sided elongation shape is not generated from the initial stage of rolling, so that it is possible to improve the quality and the yield. Further, the occurrence of the plate breakage phenomenon caused by the one-side elongation is eliminated, and the efficiency can be improved. The industrial value of the method of the present invention having such effects is very large.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a thickness distribution, a thickness difference, and an elongation difference between an entrance side and an exit side of a rolling mill in rolling of a metal strip.

FIGS. 2 to 5 are explanatory diagrams showing linear relationships between plate thickness differences ΔHe and ΔHq and elongation differences Δεe and Δεq, respectively.

6 to 9 are asymmetric shape control term groups dWb, dWI, d
It is each explanatory drawing which shows the linear relationship of each of P and ddelta, and each of elongation rate difference (DELTA) e and (DELTA) (epsilon) q.

FIG. 10 is a diagram showing the elongation percentage over the entire plate width in Examples and Comparative Examples as an elongation difference with respect to the center of the plate width.

FIG. 11 is an explanatory diagram showing a rolling state by a six-high rolling mill.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Work roll 2 Intermediate roll 3 Backup roll 4 Metal band Wb Bending force on operation side of work roll Wb 'Bending force on driving side of work roll Ib Bending force on operation side of intermediate roll Ib' Bending force on driving side of intermediate roll P Rolling force applied to the operation side of the backup roll P 'Rolling force applied to the drive side of the backup roll δ Shift position of the upper intermediate roll δ' Shift position of the lower intermediate roll L Metal plate on the exit side of the rolling mill Center position of width HeW Thickness of plate side end of metal strip on operation side of metal strip at entry side of rolling mill HqW Thickness of quarter section on operation side of metal strip at entry side of rolling mill HeD Driving of metal strip at entry side of rolling mill HqD Thickness of the quarter on the driving side of the metal strip at the entry side of the rolling mill heW Thickness of the operation side of the metal strip at the exit side of the rolling mill HqW The thickness of the quarter part on the operation side of the metal strip on the exit side of the rolling mill heD The thickness of the driving side of the metal strip on the exit side of the rolling mill The thickness of the plate side end of the metal strip hqD The driving side of the metal strip on the exit side of the rolling mill Quarter thickness

Claims (3)

(57) [Claims] 1. An asymmetrical single-sided metal strip having a plate thickness gradually decreasing from one side end to the other side end of a sheet width is formed on an operation side by using a multi-high rolling mill of four or more rolling mills. Or a part of the asymmetrical shape control term group consisting of the bending force difference dWb of the work roll between the work roll and the drive side, the bending force difference dIb of the intermediate roll, the rolling force difference dP of the backup roll, and the shift position difference dδ of the upper and lower intermediate rolls. In the set-up control when rolling to a predetermined cross-sectional shape by the control of all, in the plate width end of the metal strip on the rolling mill side, both plate side ends and both sides equidistant to each of the operation side and the drive side from the center of the plate width the respect elongation quota portions, so that elongation difference △ Ipushironq each target value △ .epsilon.e ₀ and △ εq ₀ between each other elongation difference △ .epsilon.e and quarter portion between the plate-side ends, the asymmetric shape System The control amount dW ₁ and dW ₂ Select any two asymmetrical control term dW ₁ 'and dW _2' from the term group of the formula ## EQU1 ## The following Here, ΔHe: difference in plate thickness between plate-side end portions equidistant from the center of the width of the metal band on the entry side of the rolling mill to the operation side and the drive side, respectively, ΔHq: metal band on the entry side of the rolling mill A thickness difference between the quarter portions at equal distances from the center of the width of the plate to the operation side and the drive side, respectively: a: a coefficient indicating a gradient of △ εe with respect to △ He in a linear relationship indicated by △ He and △ e; b: a coefficient indicating the slope of △ εe with respect to △ Hq in the linear relation indicated by △ Hq and △ εe, c: a coefficient indicating the slope of △ εq with respect to △ He in the linear relation indicated by △ He and △ εq, d: △ Hq and △ Ipushironq and the coefficient showing the inclination of △ Ipushironq for △ Hq in the linear relationship shown, e: dW ₁ and △ .epsilon.e a coefficient that indicates the inclination of △ .epsilon.e for dW ₁ in the linear relation shown is, f: dW ₂ coefficient indicating the slope of △ .epsilon.e for dW ₂ in the linear relation shown by the the △ .epsilon.e, g: W ₁ and △ Ipushironq and the coefficient showing the inclination of △ Ipushironq for dW ₁ in the linear relation shown, h: dW ₂ and △ Ipushironq and the coefficient showing the inclination of △ Ipushironq for dW ₂ in the linear relation shown, be set according to A setup control method in rolling of a single crown metal strip, characterized in that: 2. The method according to claim 1, wherein the two asymmetric shape control terms dW ₁ ′ and dW ₂ ′ are arbitrarily selected in addition to the two asymmetric shape control terms dW ₁ ′ and dW ₂ ′. Another asymmetric shape control term dW ₃ ′ other than the shape control term is selected and set to an arbitrary control amount dW ₃ , and the control amounts dW ₁ and dW of the two asymmetric shape control terms are set.
W ₂ is calculated by the following equation: Here k: dW ₃ and △ .epsilon.e and the coefficient showing the inclination of △ .epsilon.e for dW ₃ in the linear relationship shown, m: dW ₃ and △ Ipushironq a coefficient that indicates the inclination of △ Ipushironq for dW ₃ in the linear relationship indicated, A setup control method in rolling of a single crown metal strip, characterized by setting according to the following. 3. The setup control method for rolling a single crown metal strip according to claim 1, wherein the remaining two asymmetric shape control terms dW other than the _two asymmetric shape control terms dW ₁ ′ and dW ₂ ′ arbitrarily selected. Arbitrary control amounts dW ₃ and dW ₄ are set for each of ₃ ′ and dW ₄ ′, and
The two control variables dW ₁ and dW ₂ are calculated by the following equation: Here k: dW ₃ and △ .epsilon.e and the coefficient showing the inclination of △ .epsilon.e for dW ₃ in the linear relationship shown, m: dW ₃ and △ Ipushironq a coefficient that indicates the inclination of △ Ipushironq for dW ₃ in the linear relationship indicated, n: dW ₄ and △ .epsilon.e and the coefficient showing the inclination of △ .epsilon.e for dW ₄ in the linear relationship shown, r: dW ₄ and △ Ipushironq a coefficient that indicates the inclination of △ Ipushironq for dW ₄ in the linear relationship shown is set according to, A setup control method in rolling of a single crown metal strip.