JP2962910B2 - Shape 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 method for controlling the shape of a single crown metal strip having asymmetrical shapes on both sides when the metal strip is rolled into a predetermined sectional shape.

[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”) once rolled to an intermediate thickness is slit in the longitudinal direction into a narrow width material, and the number of cases where the material is further rolled is increasing recently. That is. In general, the thickness of the rolled material is the thickest at the center of the width and gradually decreases symmetrically toward both side edges, and, for example, when slitting left and right in the middle of the width of the wide material, this way. The obtained slit material has a one-crown plate thickness distribution 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 piece crown material is rolled, asymmetrical rolling conditions are required so that the sectional shape does not become one-sided, that is, the sectional shape is similar to that before rolling.

[0003] Such a rolling situation will be described with reference to the drawings. FIG. 20 is an explanatory diagram showing a rolling state by a six-high rolling mill. As shown in FIG. 20, 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 are shown in FIG. Bending force Ib,
Ib ', the rolling forces P and P' applied to the operation side and the drive side of the backup roll 3, and the shift position on each of the operation side of the upper intermediate roll 2 and the drive side of the lower intermediate roll 2 (in the present invention, this is simply referred to as It is adopted to make a difference between δ and δ ′ (referred to as a shift position of the upper and lower intermediate rolls) (such a method is referred to as asymmetrical shape control means), thereby changing the deflection and inclination of the work roll 1, The metal strip 4 is rolled by controlling the difference in each of the above-mentioned rolling conditions so that the elongation percentages on the operation side and the drive side become equal.

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 shape of the work roll 1 on the drive side and the operation side during the setup (setting of conditions for starting the rolling) is not clear because the relationship between the shape of the work roll 1 and the shape on the rolling mill exit side (that is, after rolling) is not clear. The difference dWb, 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 dWb, dIb, dP, and dδ may be collectively referred to as an asymmetric shape control term), and of course, the pressing force of each roll acting on the material to be rolled is indicated on the drive side. And the operation side, the average bending force <Wb> of the work roll 1, the average bending force <Ib> of the intermediate roll 2, and the average shift position <δ> of the upper and lower intermediate rolls 2 (hereinafter, these <Wb>, <Ib>
(b> and <δ> may be collectively referred to as a symmetric shape control term) at present. Therefore, there were problems such as the occurrence of shape defects such as one-sided elongation, medium elongation, and elongation of the metal band 4 in the initial stage of rolling. Also, after the start of rolling, when the rolled material is wound on a reel, a difference in winding diameter occurs between the operating side and the drive side as the winding amount of the reel increases due to the shape of a single crown, and the roll is rolled from the rolling mill. The distance to the winding position differs. For this reason, a tension fluctuation occurs in the plate width direction, and the shape information from the shape detector for obtaining the shape from the tension distribution in the plate width direction is different from the actual shape, and there is a problem that effective control cannot be performed.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides not only a setup control in which a thickness distribution in the width direction at the entry side of the rolling mill is sufficiently considered, but also an effective shape control after rolling. To perform rolling without shape defects from the start of rolling to the end of rolling.

[0006]

SUMMARY OF THE INVENTION The present inventors have considered setup control taking into account the thickness distribution in the strip width direction on the entry side of the rolling mill, and consideration of tension fluctuation in the strip width direction at the time of reel winding after the start of rolling. As a result of various investigations to configure a shape control method in the rolling of the single crown metal strip, the plate side ends and both sides which are equidistant from the center of the width of the metal strip toward the operation side and the drive side. Regarding the elongation and thickness at each of the quarters, the elongation difference △ εe between the plate-side ends on the exit side of the rolling mill, the elongation difference △ εq between the quarters, The difference △ εe 'between the average elongation at the plate-side end and the difference △ εq' between the elongation at the center of the plate width and the average elongation at both quarters, and the difference between the plate-side ends at the rolling mill entry side Between the thickness difference between He and the thickness difference between the quarters ΔHq A linear relationship is established, whereby it is possible to set the control amount of the asymmetric shape control term and the symmetric shape control term in consideration of the thickness distribution on the entry side of the rolling mill in the setup, and after the start of rolling, the width direction of the shape detector. Thus, the present invention was completed by investigating that the shape control can be effectively performed until the end of rolling by correcting the tension variation of the above and setting the control amount of each of the above-mentioned control items while constantly correcting it.

That is, according to the present invention, the elongation difference Δεe, Δε
Using the fact that each of q, △ εe ′ and △ εq ′ and the plate thickness differences △ He and △ Hq are in a linear relationship, in setup, △ εe, △ εq, △ εe ′ and △ εq ′ Are the target values △ εe ₀ , △ εq ₀ , △ εe ₀ ′ and △ εq ₀ ′, respectively.
Any two of the asymmetric shape control term groups dWb, dIb, dP and dδ and the symmetric shape control term group <W
b>, <Ib> and <δ>, the control amount is rationally derived and set for any two, and after the start of rolling, the thickness distribution in the width direction on the entry side of the rolling mill and the rolling Continuously measure the plate shape on the machine-out side and the passing position distribution in the plate width direction before reel winding, the control amount of each arbitrarily selected control item,
A shape control method in rolling of a one-crown metal strip, in which a tension change in a sheet width direction caused by a one-crown at the time of winding is continuously set while continuously correcting the tension to control a plate shape, It is configured as follows.

[0008] A single-sided metal band with asymmetrical shape on both sides is
When rolling up a reel while rolling using a multi-high rolling mill or higher, the elongation difference Δεe between the plate side edges on both sides in the metal band width direction and the quarter on both sides in the metal band width direction during setup. elongation difference between the parts between △ Ipushironq each target value △ .epsilon.e ₀ and △ bending force difference Ipushironq ₀ become as the operation side of the work rolls and the drive side DWB, also the intermediate roll bending force difference DIB, also the backup Any two asymmetric shape control term groups are selected from the asymmetric shape control term groups consisting of the roll rolling force difference dP and the shift position difference dδ of the upper and lower intermediate rolls, and the control amounts dW ₁ and dW ₂ are selected.
With the following formula

[0009]

(Equation 3) 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 each of the operation side and the driving side ΔHq: metal band on the entry side of the rolling mill The thickness is set in accordance with the thickness difference between the quarter portions which are equidistant to the operation side and the drive side from the center of the plate width, and the elongation percentage at the center of the plate width and the average elongation percentage at the plate side ends on both sides are set. Difference Δεe ′ and the difference Δε between the elongation at the center of the plate width and the average elongation at the quarters on both sides.
The average bending force <Wb> between the operation side and the drive side of the work roll, the average bending force <Ib> of the intermediate roll, and the upper and lower middle so that q ′ becomes the target values △ εe ₀ ′ and △ εq ₀ ′, respectively. Any two symmetrical shape control terms are selected from a group of symmetrical shape control terms consisting of the average shift position <δ> of the roll, and their control amounts <W ₁ > and <W ₂ > are expressed by the following equations.

[0010]

(Equation 4) After starting the rolling by setting according to the following, the thickness distribution in the width direction on the entry side of the rolling mill, the shape of the sheet on the exit side of the rolling mill, and the passing position distribution in the width direction before the reel winding are continuously performed. And elongation difference △ εe, △ εq between the plate side ends and between the quarters, corrected for the tension fluctuation in the plate width direction caused by one crown during reel winding. The difference △ εe ′ and △ εq ′ between the center elongation and the average elongation of the plate side edges on both sides and the average elongation of both quarters are calculated by the following eight equations,

Dεe = −ln (LeW / LeD) dεq = −ln (LqW / LqD) dεe ′ = − ln (LeW / Lc) / 2−ln (LeD / L
c) / 2 dεq ′ = − ln (LqW / Lc) / 2−ln (LqD / L
c) / 2 △ εe = △ εe 2 -dεe △ εq = △ εq 2 -dεq △ εe '= △ εe 2' -dεe '△ εq' = △ εq 2 '-dεq' here, dεe: exits the rolling mill Dεq: Elongation difference corresponding to the tension fluctuation difference between the quarter parts dεe ′: Tension fluctuation at the center of the plate width and the plates on both sides Elongation difference dεq ′ corresponding to the difference in average tension fluctuation at the side end dεq ′: Elongation difference Lc, LeW, corresponding to the difference between the tension fluctuation at the center of the plate width and the average tension fluctuation at the quarters on both sides LqW, LeD, LqD: distances from the rolling mill to the reel winding position at the plate width center, the operation side plate side end, the operation side quarter portion, the drive side plate side end, and the drive side quarter portion, respectively. .epsilon.e _2: rolling mill stretching out index difference between the plate-side ends of the installation shape detector by directly obtained the delivery side of the rolling mill on the side △ εq _2: on the delivery side of the rolling mill Elongation difference between the delivery side of the rolling mill of the quota portions obtained directly by location shape detector △ .epsilon.e ₂ ': rolling mill exit was placed in side shape detector by the rolling mill outlet side of the plate width central obtained directly Difference between the elongation percentage and the average elongation percentage at both ends of the strip side Δεq ₂ ': The elongation percentage at the center of the strip width at the exit side of the rolling mill and the quarter on both sides directly obtained by the shape detector installed on the exit side of the rolling mill The difference between the average elongation rate of the part and the target values 伸 び Ee ₀ and △ Eq _{0 of the} difference in the elongation rate between the plate side ends and between the quarter parts, a target value of the difference between the respective average growth rate of the average growth rate and both quota portions △ Ee ₀ 'and △ Eq _0', the next four formula _{△ Ee 0 = △ εe 0 +} β × (△ εe 0 − △ εe) △ Eq ₀ = △ εq ₀ + β × (△ εq ₀ − △ εq) △ Ee ₀ '= △ εe ₀ ' + β × (△ εe ₀ '− △ εe') △ Eq ₀ '= △ εq ₀ '+ Β × (△ εq ₀ '- △ _εq') where beta: by substituting each of the formula obtained by a factor used to adjust the correction (A) and (B), the control amount of the asymmetrical control term and the control amount of the symmetrical control term Is set while constantly correcting to control the plate shape. The coefficients a, b, c, d, e, f, g, h, a ', b', c ', which are the respective coefficients in the above equations (A) and (B).
d ', e', f ', g', h ', k', and m 'are described below.

Hereinafter, a method for controlling the shape of a single crown metal strip according to the present invention in rolling will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of sheet thickness distribution, sheet thickness difference and elongation difference between the entrance side and the exit side of a rolling mill in rolling of a metal strip, and FIGS.
FIG. 6 is an explanatory diagram showing a linear relationship between the plate thickness differences ΔHe and ΔHq and the elongation differences Δεe and Δεq, respectively.
9 are explanatory diagrams showing a linear relationship between each of the asymmetric shape control terms dWb, dWI, dP, and dδ and each of the elongation differences Δεe and Δεq, and FIGS.
He and ΔHq and elongation difference Δεe ′ and Δεq ′
FIGS. 14 to 1 are explanatory diagrams showing a linear relationship with each of FIGS.
6 is an explanatory diagram showing a linear relationship between each of the symmetric shape control term groups <Wb>, <Ib>, and <δ> and each of the elongation differences eεe ′ and △ εq ′, and FIG. FIG. 18 is a schematic explanatory view for explaining the state of implementation of the embodiment, FIG. 18 is a diagram showing the transition of the maximum steepness in the embodiment and the comparative example, and FIG. 19 is a diagram in which the distance from the rolling mill to the reel winding position in the sheet width direction is different. It is explanatory drawing for demonstrating a different thing.

Hereinafter, a six-high rolling mill will be described as an example. First, in the method of the present invention, as shown in FIG. 1, the operation side and the driving side (in the drawing, the thicker the sheet thickness) than the center position (line L in FIG. 1) of the metal strip on the exit side of the rolling mill. The thicknesses of the plate-side ends on both sides and the quarter parts on both sides, which are equidistant from each other toward the operation side (but are not restricted thereto), are 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 center of the plate width is Hc, 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 side end at the drive side is the same. Is heD, the thickness of the quarter portion is hqD, and the thickness at the center of the width is hc. In the present invention, the plate-side end is a position 20 mm from the plate-side end because the thickness of the rolled metal strip generally decreases sharply from a position about 20 mm from the plate end to the plate-side end. 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 率 εe between the plate-side ends on the exit side of the rolling mill, the elongation difference △ εq between the quarter portions, the elongation at the center of the sheet width and the metal The difference △ ε 'between the average elongation at the plate-side end on both sides in the band width direction and the difference △ ε between the elongation at the center of the plate width and the average elongation at the quarters on both sides
q ′, the relationship between the thickness difference ΔHe between the plate-side ends on the rolling mill entry side and the thickness difference ΔHq between the quarter portions, and the elongation differences Δεe and Δεq. The relationship between each of them and each of dWb, dIb, dP and dδ of the asymmetric shape control terms, and further, each of the elongation difference △ εe ′ and △ εq ′ and the symmetric shape control terms <Wb>, <Ib> and <δ> Expressions (A) and (B) for obtaining the control amount are derived by considering the relationship with each of them. 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, Δεq, 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) Δεe ′ = − {ln (heW / HeW) −ln (hc / Hc)} / 2− {ln (heD / HeD) −ln (hc / Hc)} / 2 (5) Δεq ′ =-{Ln (hqW / HqW) -ln (hc / Hc)} / 2-{ln (hqD / HqD) -ln (hc / Hc)} / 2} (6) It is the ratio between the difference in strain in the rolling direction and the difference in strain in the plate thickness direction between the drive side and the drive side.)

Equations (3) to (6) 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 ″, rolling is one type of plastic working. Ε + ε ′ + ε ″ = 0 ‥‥ (7) 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 ＝ (8) Here, assuming that the sheet width hardly changes before and after rolling, the strain difference ε ″ in the sheet width direction is calculated. If not considered, △ ε = − △
ε ′, where Δ 比 = − 圧 延 ε ′ ‥‥ (9) where Δ is the ratio of the strain difference in the rolling direction and the thickness direction in consideration of the strain difference in the sheet width direction. Further, since the strain in the thickness direction is a true strain (logarithmic strain) and is represented by the general formula ln (h / H), the formulas (3) to (6) are obtained by combining with the relationship of the formula (9).

As a result of examination 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 ₁ ‥‥ (10) Δεq = c △ He + d △ Hq + k ₂ ‥‥ (11) where k ₁ and k ₂ 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 16 described later are data obtained by using the same six-rolling mill used in the examples described later. Equation (1
0), when △ Hq is constant, as shown in FIG.
e and △ He are in a linear relationship, and a is △ εe for △ He
Is a coefficient indicating the slope of Also, in equation (10), ΔH
When e is constant, as shown in FIG. 3, △ e and 関係 Hq are in a linear relationship, and b is a coefficient indicating the slope of △ e with respect to △ Hq. The same applies to equation (11), where c and d are coefficients indicating the slope of Δεq with respect to ΔHe and the slope of Δεq with respect to ΔHq, respectively, as shown in FIGS. 4 and 5.

In Equations (10) and (11), when the thickness difference ΔHe and ΔHq are both set to 0 when the asymmetrical shape control means is not used, the thickness distribution on the rolling mill entry side becomes bilaterally symmetric. From the above, the rolling mill outlet side shape is also symmetrical (that is, Δεe = 0,
Δεq = 0). Therefore, the constant terms k ₁ and k ₂ are both 0, and the equations (10) and (11) are as follows: Δεe = a △ He + b △ Hq ‥‥ (12) Δεq = c △ He + d △ Hq ‥‥ (13) Becomes These are collectively displayed as a matrix as follows.

(Equation 5)

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.

Two control terms dW ₁ and dW ₂ are arbitrarily selected from the group of asymmetrical shape control terms, and dW ₁ and dW ₂ are determined in a linear relationship established between each of them and each of the elongation differences Δεe and Δεq. Let e be a coefficient indicating the slope of △ εe with respect to ₁ (the same meaning as the slope in the case of a), and △ with respect to dW ₂
A coefficient indicating the slope of ee is denoted by f, a coefficient indicating the slope of △ εq with respect to dW ₁ is denoted by g, and a coefficient indicating the slope of △ εq with respect to dW ₂ is denoted by h.

The influence of each asymmetric shape control means can be considered by adding. That is, assuming that the control amounts of the asymmetric shape control terms to be applied are dW ₁ and dW ₂ , respectively (the same signs as the control terms are used for the control amounts in order to avoid complication of the codes; the same applies to the following), Expression (12) And equation (13) are as follows. Δεe = a △ He + b △ Hq + edW ₁ + fdW ₂ ‥‥ (15) Δεq = c △ He + d △ Hq + gdW ₁ + hdW ₂ ‥‥ (16) These are collectively displayed as a matrix as follows.

(Equation 6)

In equation (17), the elongation difference △ εe, △ εq
Are set as target values △ εe ₀ and △ εq _{0 respectively,} and the control amount d
By solving for W ₁ and dW ₂ , the control equation (18), which is the above equation (A), is obtained.

(Equation 7) 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 (18), dW ₁ and dW ₂ can be set.

When the control amounts (<Wb>, <Ib> and <δ>) of any of the symmetric shape control terms are fixed, the elongation differences Δεe ′ and Δεq ′ and the sheet thickness difference Δ H
It has been found that a linear relationship holds between e and ΔHq. Therefore, the elongation difference △ εe ′ and △ εq ′ are expressed by the following equations. Δεe ′ = a ′ △ He + b ′ △ Hq + e ′ ‥‥ (19) Δεq ′ = c ′ △ He + d '△ Hq + f ′ ‥‥ (20) where e ′ and f ′ are constant terms and ΔHe △ εe ′ and △ εq ′ when both 場合 Hq and △ Hq are zero.

Here, the coefficients a ', b', c 'and d'
Will be described with reference to FIGS. Assuming that 一定 Hq is constant in equation (19), as shown in FIG.
And △ He are in a linear relationship, and a ′ is △ ε for △ He
This is a coefficient indicating the slope of e '. In equation (19), △
When He is kept constant, as shown in FIG.
and q have a linear relationship, and b 'is a coefficient indicating the slope of △ e' with respect to △ Hq. Similarly, in equation (20), c ′ and d ′ are coefficients indicating the slope of Δεq ′ with respect to ΔHe and the slope of Δεq ′ with respect to ΔHq, respectively, as shown in FIGS. . Equation (19) and Equation (2)
0) are displayed in a matrix as follows.

(Equation 8)

Next, for the case where the control amounts of all the symmetric shape control terms are fixed as described above, an appropriate control amount is determined in consideration of the effect of changing the control amount. After examining many rolling conditions, the elongation difference
Each of εe ′ and △ εq ′ is a symmetric shape control term group <W
It has been found that there is a linear relationship between any of <b>, <Ib> and <δ>. In each example of the linear relationship, the relationship with <Wb> is shown in FIG. 14, the relationship with <Ib> is shown in FIG. 15, and the relationship with <δ> is shown in FIG.

Any two control terms <W ₁ > and <W ₂ > are arbitrarily selected from the symmetrical shape control term group, and are established between each of them and each of the elongation difference △ εe ′ and △ εq ′. In the linear relationship, a coefficient indicating the slope of △ εe ′ with respect to <W ₁ > (same meaning as the slope in the case of a ′) is g ′,
H ′ is a coefficient indicating the slope of △ εe ′ with respect to <W ₂ >
A coefficient indicating the slope of △ εq ′ with respect to <W ₁ > is defined as k ′, and a coefficient indicating the slope of △ εq ′ with respect to <W ₂ > is defined as m ′.
And

The effect of each symmetric shape control means can also be considered in addition. That is, if the control amounts of the applied symmetric shape control terms are <W ₁ > and <W ₂ >, respectively, the equation (19)
And equation (20) are as follows. Δεe ′ = a′ΔHe + b′ΔHq + e ′ + g ′ <W ₁ > + h ′ <W ₂ > ‥‥ (22) Δεq ′ = c ′ △ He + d ′ △ Hq + f ′ + k ′ <W ₁ > + m ′ < W ₂ > ‥‥ (23) These are collectively displayed as a matrix as follows.

(Equation 9)

In equation (24), if the elongation difference △ εe ′ and △ εq ′ are set as target values △ εe ₀ ′ and △ εq ₀ ′, respectively, and the control variables <W ₁ > and <W ₂ > are solved. The above formula
The control formula (25) that is (B) is obtained.

(Equation 10) Therefore, the coefficients a ', b', c ', d', e ', f',
g ′, h ′, k ′, and m ′ can be determined in advance as a function of rolling conditions such as rolling load and strip width, and <W ₁ > and <W ₂ > can be set according to equation (25).

By obtaining and setting the control amount of the asymmetric shape control term and the control amount of the symmetric shape control term, setup control can be performed so as not to cause a shape defect at the beginning of rolling. You can.

Even after the rolling is started in this way, in the method of the present invention, by continuously measuring the thickness distribution in the width direction on the entrance side of the rolling mill and the shape of the sheet on the exit side of the rolling mill, Rolling is continued by setting the asymmetrical shape control term and the symmetrical shape control term continuously. At this time, as the rolled material is wound on a reel, the tension fluctuation in the sheet width direction caused by the single crown occurs. , The target values of the elongation rate differences △ εe ₀ , △ εq ₀ , △ εe ₀ ′, and △ εq ₀ ′ are corrected as described below to control the control amount of the asymmetric shape control term and the control of the symmetric shape control term. By constantly correcting the set value of the quantity, it becomes possible to manufacture a metal strip closer to the target shape. The plate shape on the exit side of the rolling mill is obtained as shape information by a shape detector. A method of correcting the set values of the control amount of the asymmetric shape control term and the control amount of the symmetric shape control term based on the shape information will be specifically described.

As shown in FIG. 19, when the one-crown metal band is wound on the reel 5, the distance from the rolling mill to the reel winding position is different between the operation side and the drive side, so that a tension variation in the sheet width direction occurs. . Elongation difference dεe corresponding to the difference in tension fluctuation between the plate side ends on the rolling mill exit side and elongation difference dεq corresponding to the difference in tension fluctuation between the quarters.
And the elongation difference dεe ′ corresponding to the difference between the amount of tension fluctuation at the center of the plate width and the average amount of tension fluctuation at the plate side edges on both sides, and the average of the amount of tension fluctuation at the plate width center and the average of the quarter portions on both sides. The elongation percentage difference dεq ′ corresponding to the difference with the tension fluctuation amount is expressed by the following equation.

Dεe = −ln (LeW / LeD) ‥‥ (26) dεq = −ln (LqW / LqD) ‥‥ (27) dεe ′ = − ln (LeW / Lc) / 2-ln (LeD / Lc) / 2 ‥‥ (28) dεq ′ = − ln (LqW / Lc) / 2−ln (LqD / Lc) / 2 ‥‥ (29) (Lc, LeW, LqW, LeD and LqD are the center of the sheet width, respectively. It indicates the distance from the rolling mill to the reel winding position at the side plate side end, the operation side quarter section, the drive side plate side end, and the drive side quarter section.)

Accordingly, the elongation difference Δεe between the plate-side ends on the exit side of the rolling mill, the elongation difference Δεq between the quarter portions, the elongation at the center of the sheet width, and the average elongation at both sheet-side ends. Difference from rate と ε
e ′ and the difference △ εq ′ between the elongation at the center of the strip width and the average elongation at the quarters on both sides are the difference between the sheet-side ends on the rolling mill exit side directly obtained by the shape detector installed on the rolling mill exit side. the difference between the elongation index difference △ .epsilon.e _2, elongation difference between the quarter portions △ εq _2, sheet width center of elongation and opposite sides of the plate-side end average growth rate of between △
εe ₂ ′ and the difference △ εq ₂ ′ between the elongation at the center of the sheet width and the average elongation at the quarter portions on both sides, and the elongation dεe, dεq, dεe ′ and dεq ′ corresponding to the difference in the amount of tension fluctuation. The difference is expressed by the following equation. △ εe = △ εe ₂ −dεe ‥‥ (30) △ εq = △ εq ₂ −dεq ‥‥ (31) △ εe '= △ εe ₂ ' −dεe '‥‥ (32) △ εq' = △ εq ₂ ' −dεq ′ ‥‥ (33)

Next, the target values △ εe ₀ , △ εq ₀ , △ ε
e ₀ ′ and △ εq ₀ ′ and the above equations (30) to (33)
By comparing with each of △ εe, △ εq, 'εe ′ and △ εq ′, the target values △ εe ₀ , △ εq ₀ , △ εe ₀ applied to equations (18) and (25) 'And △ εq ₀ '
(Hereinafter, these are referred to as △ Ee ₀ , △ Eq ₀ , △ Ee ₀ ′ and △ Eq ₀ ′
Is rewritten as follows: ΔEe ₀ = △ εe ₀ + β × (△ εe ₀ − △ εe) ‥‥ (34) △ Eq ₀ = △ εq ₀ + β × (△ εq ₀ − △ εq) ‥‥ (35) △ Ee ₀ '= △ _{εe 0 '+ β × (△} εe 0' - △ εe ') ‥‥ (36) △ Eq 0' = △ εq 0 '+ β × (△ εq 0' - △ εq ') ‥‥ (37) In this case, △ εe ₀ etc. is a target value as a finished rolled product, and △ Ee ₀ etc. are obtained by using equations (18),
This applies to (25).

Here, β is a coefficient used for adjusting the correction, and takes a value in the range of 0 ≦ β ≦ 1. This correction coefficient β
Are the target elongation differences △ εe ₀ , △ εq ₀ , △ εe ₀ ′ and △ ε
When q ₀ ′ and the measured shapes △ εe, △ εq, △ εe ′ and △ εq ′ are different, the setting value of the shape control means based on the thickness distribution measured by the sheet crown meter, the shape detector and This is a coefficient indicating which of the shape information obtained by correcting the tension variation obtained by the displacement meter is weighted, and the correction coefficient β
It means that the larger the value is, the more the latter is weighted. As the correction coefficient β, an appropriate set value can be obtained by an experiment.

Also, Lc, LeW, LqW, LeD, LqD
By setting a displacement meter between the deflector roll 6 and the reel 5 and measuring the distribution of the threading position in the strip width direction, the rolling mill, the deflector roll 6 and the reel 5
Can be calculated from the positional relationship of Examples of the displacement meter include a linear encoder and a potentiometer for a contact type, and an optical micro and an eddy current sensor for a non-contact type. Note that, as the shape detector, a detector which is divided and arranged in the width direction of the metal band and detects the tension acting on the metal band at each portion by a load cell is shown.

Thus, the equations (34) and (35) are converted to the control equation (18), and the equations (36) and (37) are converted to the control equation (2).
5) by continuously setting the control amount of the asymmetric shape control term and the control amount of the symmetric shape control term while constantly correcting the target value in each of the above equations, so that the target shape is close to the target shape until the end of rolling. Rolling into a metal strip becomes possible.

In order to prevent shape defects such as elongation of the metal strip after rolling, the cross sections of the metal strip before and after rolling should be as similar as possible. 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 expression during setup
In (18), the control amounts dW ₁ and dW ₂ are set so that both the target values △ εe ₀ and △ εq ₀ become zero, and in the control equation (25), the target values △ εe ₀ ′ and △ εq ₀ ′ are By setting the control variables <W ₁ > and <W ₂ > so that both become zero, rolling can be performed from the beginning of rolling to the end of rolling without causing any shape defects such as unilateral elongation, medium elongation, and ear elongation. I can do it.

Although the method of the present invention has been described using a six-high rolling mill, the same control method can be used in a multi-high rolling mill rather than a six-high rolling mill. When such a multi-high rolling mill is provided with a plurality of intermediate rolls and backup rolls, dP, dIb, dδ
About dP (difference in rolling force between the operating side and the driving side on the uppermost backup roll), dIb (bending force difference between the operating side and the driving side of the intermediate roll in contact with the work roll), dδ (contact with the work roll) DWb, dIb, dP, d
The control amounts dW ₁ and dW ₂ are set according to the control equation (18) using any two means of δ, and <Wb>, <Ib>, <δ>
For <Wb> (average bending force between the operation side and drive side of the work roll), <Ib> (average bending force between the operation side and drive side of the intermediate roll in contact with the work roll), and <δ> (workpiece <Wb>, <Ib>, <Wb>, <Ib>,
What is necessary is just to set the control amounts <W ₁ > and <W ₂ > according to the control formula (25) using any two means of <δ>.

[0040]

Embodiments of the method of the present invention will be described below. The rolling mill used was a standard work roll (135mm, 850mm, 1075mm) and an intermediate roll (300m) whose roll specifications are shown in parentheses in the order of roll diameter, roll body length, and chock distance.
m, 850 mm, 1660 mm) and backup roll (630 mm, 8
50 mm, 1475 mm) with the same roll configuration as in FIG. 20 and asymmetric shape control terms dWb, dIb, d
P, dδ and symmetric shape control terms <Wb>, <Ib>,
<Δ> was controllable.

Using such a six-high rolling mill, a sheet width of 600 m
work selected from asymmetric shape control terms when rolling a single crown material of ordinary steel with a thickness of 0.6 mm, a thickness of exit side of 0.36 mm and a rolling load of 170 ton in a rolling mill. roll bending force difference dWb asymmetric shape control means according to (a control amount and dW ₁₎ and the intermediate roll bending force difference DIB (the control amount and dW _2), any out of the symmetrical control term group the average bending force of the selected work roll in <Wb> (the control amount is set to <W _1>) and the average bending force of the intermediate roll <Ib> (the control amount is set to <W _2>) by symmetrical control Control was performed by means.

Hereinafter, the procedure of this embodiment will be specifically described with reference to FIG. The sheet thickness distribution in the sheet width direction is measured by a sheet crown meter 8 installed on the entrance side of the rolling mill, the measured information is sent to the computer 11, and the sheet thickness distribution in the sheet width direction is approximated by a quartic equation. He and △ Hq are calculated. In addition, the computer 1 uses the rolling information such as the rolling load and the sheet width from the setting panel 7 to calculate
The coefficients a to h and a 'to m' are calculated by one. And
The control formula is calculated by the computer 11 using △ He, △ Hq and the coefficients a to h.
(18) dW ₁ and dW ₂ are calculated from, △ He, △ Hq and controlled by the coefficient A'～m 'from (25) <W _1> and <W _2> is calculated. dW ₁ , dW ₂ , <W ₁ > and <W
₂ > The work roll bending force and the intermediate roll bending force on the operation side and the drive side are calculated, and are sent to the work roll bending force command devices 12 and 13 and the intermediate roll bending force command devices 14 and 15, and the operation side and the drive side are calculated. Are output to the work roll benders 16 and 17 and the intermediate roll benders 18 and 19, and the rolling is started in a state where the setup control is performed.

After the start of rolling, the sheet thickness distribution in the sheet width direction is continuously measured by the sheet crown meter 8. At the same time,
The distribution of the threading position in the sheet width direction is continuously measured by a displacement gauge 10 installed between the deflector roll 6 and the reel 5, and a computer 11 calculates Lc from the positional relationship between the rolling mill, the deflector roll 6 and the reel 5. , LeW, LqW, LeD,
LqD is calculated, and dεe, dε is calculated according to equations (26) to (29).
q, dεe ′, dεq ′ are calculated, and based on the shape information obtained by continuous measurement of the shape detector 9 installed on the exit side of the rolling mill, {εe ₀ , △ ε
q ₀ , △ εe ₀ ′ and △ εq ₀ ′ are corrected to △ Ee ₀ , △ E
q ₀ , △ Ee ₀ ′ and △ Eq ₀ ′ are obtained, whereby the control equation
DW ₁ and dW ₂ calculated from (18) and <W ₁ > and <W ₂ > calculated from control formula (25) are constantly corrected,
It is sent to the work roll bending force command devices 12 and 13 and the intermediate roll bending force command devices 14 and 15,
The output is output to the work roll benders 16 and 17 on the operation side and the drive side and the intermediate roll benders 18 and 19, and the work roll bending force and the intermediate roll bending force on the operation side and the drive side are constantly corrected.

FIG. 18 shows the transition of the maximum steepness (the maximum value of the steepness in the sheet width direction) in the case of the present embodiment in which the shape control is actually performed using the method of the present invention as described above.
It is shown in (a). For comparison, as before, the bending force difference dWb of the work roll, the bending force difference dIb of the intermediate roll, the average bending force <Wb> of the work roll, and the average bending force <Ib> of the intermediate roll were empirically set, and FIG. 18B shows the transition of the maximum steepness when the shape control is performed without correcting the shape information obtained by the detector. In case (a) according to the method of the present invention, it can be seen that the maximum steepness is kept within 0.3% from the start of rolling. On the other hand, in the case of the conventional method (b),
The maximum steepness increases in the latter half of rolling when the tension fluctuation at the start of rolling and when winding on a reel increases, and 1%
That's all.

[0045]

As described above in detail, the shape control method in the rolling of a single crown metal strip according to the present invention is characterized in that the elongation differences △ εe, △ εq, △ εe ′ and △ εq ′ are reduced in the rolling of the single crown material. Using the fact that each of them and each of the plate thickness differences ΔHe and ΔHq are in a linear relationship, an asymmetric shape control term d is used.
For any two of Wb, dIb, dP, and dδ and any two of the symmetric shape control terms <Wb>, <Ib>, and <δ>, the control amount is obtained by a control formula that rationally derived. The rolling is started by controlling the setup, and the rolling is performed while always correcting the control amount with respect to the tension fluctuation in the sheet width direction at the time of reel winding caused by the one crown even after the rolling is started. From the initial stage to the end, the cross-sectional shape of the metal strip on the exit side of the rolling mill can be made 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, shape defects such as single elongation, medium elongation, and ear elongation do not occur from the initial stage of rolling. The yield can be improved. Further, the occurrence of a plate breakage phenomenon caused by the shape defect 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, dIb, dP
FIG. 4 is an explanatory diagram showing a linear relationship between each of the elongation differences Δεe and Δεq and each of the elongation differences Δεe and Δεq.

FIGS. 10 to 13 are explanatory diagrams showing a linear relationship between each of the plate thickness differences ΔHe and ΔHq and each of the elongation differences Δεe ′ and Δεq ′.

14 to 16 are symmetric shape control term groups <Wb>, <Ib>
And <δ> are each an explanatory diagram showing a linear relationship between each of elongation differences Δεe ′ and Δεq ′.

FIG. 17 is a schematic explanatory diagram for explaining an implementation state of one embodiment of the present invention.

FIG. 18 is a diagram showing transition of the maximum steepness in the example and the comparative example.

FIG. 19 is an explanatory diagram for explaining that a distance from a rolling mill to a reel winding position is different in a sheet width direction.

FIG. 20 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 strip 5 Reel 6 Deflector roll 7 Setting board 8 Sheet crown meter 9 Shape detector 10 Displacement meter 11 Computer 12,13 Work roll bending force command device 14,15 Intermediate roll bending force command Apparatus 16, 17 Work roll bender 18, 19 Intermediate roll bender 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 on driving side of intermediate roll Force P Rolling force on the operation side of the backup roll P 'Rolling force on the drive side of the backup roll δ Shift position of the upper intermediate roll δ' Shift position of the lower intermediate roll L Center of the width of the metal strip on the exit side of the rolling mill Position HeW Metal strip on the rolling mill entry side The thickness of the metal strip on the entry side of the metal strip on the operation side HqW The thickness of the quarter section on the operation side of the metal strip on the entry side of the rolling mill HeD The thickness of the driving side of the metal strip on the entry side of the metal strip on the entry side of the rolling mill HqD Thickness of the quarter part on the driving side of the metal strip at the side heW Thickness of the end of the metal side on the operation side of the metal strip on the exit side of the rolling mill hqW 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 at the exit side of the rolling mill on the strip side hqD The thickness of the quarter section on the driving side of the metal strip at the exit side of the rolling mill Lc The distance from the rolling mill to the reel winding position at the center of the strip width LeW Distance from the rolling mill to the reel winding position at the plate side end on the operating side LqW Distance from the rolling mill to the reel winding position at the quarter section on the operating side LeD Roll from the rolling mill at the plate side end on the drive side Distance to picking position Distance from the rolling mill in the quarter portion of qD drive side to the reel winding position

Claims (1)

(57) [Claims] 1. A single crown metal band having an asymmetric shape on both sides,
In winding up on a reel while rolling using a multi-high rolling mill of six or more rolling mills, the elongation difference 率 εe between the plate side ends on both sides in the metal band width direction and the The bending force difference dWb between the operation side and the driving side of the work roll, the bending force difference dIb between the intermediate rolls, and the like so that the elongation difference △ εq between the quarter portions becomes the target values △ εe ₀ and △ εq ₀ respectively. Any two asymmetrical shape control terms are selected from the asymmetrical shape control terms consisting of the rolling force difference dP of the backup roll and the shift position difference dδ of the upper and lower intermediate rolls, and their control amounts dW ₁ and dW.
W ₂ is calculated by the following equation: 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 each of the operation side and the driving side ΔHq: metal band on the entry side of the rolling mill The thickness difference between the quarter portions equidistant from the center of the width of the plate to the operation side and the drive side, respectively: a: A coefficient indicating the slope of △ εe with respect to △ He in the linear relationship indicated by △ He and △ εe b: A coefficient indicating the slope of △ εe with respect to △ Hq in the linear relationship indicated by ＨHq and △ εe c: A coefficient indicating the slope of △ εq with respect to △ He in the linear relationship indicated by △ He and △ εq d: coefficient indicating the slope of △ Ipushironq for △ Hq in the linear relation shown by the εq e: dW ₁ and △ .epsilon.e a coefficient indicating the slope of △ .epsilon.e for dW ₁ in the linear relation shown by f: indicated and dW ₂ and △ .epsilon.e coefficient indicating the slope of △ .epsilon.e for dW ₂ in linear relation g: dW ₁ and △ Ipushironq and Coefficient indicating the slope of △ Ipushironq for dW ₁ in the linear relation shown h: dW ₂ and △ Ipushironq with and are set in accordance with the coefficient indicating the slope of △ Ipushironq for dW ₂ in the linear relation shown, the the sheet width center of elongation The difference △ εe ′ between the average elongation at the plate side ends on both sides and the difference △ ε between the elongation at the center of the plate width and the average elongation at the quarters on both sides
The average bending force <Wb> between the operation side and the drive side of the work roll, the average bending force <Ib> of the intermediate roll, and the upper and lower middle so that q ′ becomes the target values △ εe ₀ ′ and △ εq ₀ ′, respectively. Any two symmetric shape control terms are selected from a group of symmetric shape control terms consisting of the average shift position <δ> of the roll, and their control amounts <W ₁ > and <W ₂ > are expressed by the following equation: Here, a ′: △ He in the linear relationship indicated by △ He and △ εe ′
Coefficient b 'indicating the slope of △ εe' with respect to △ Hq in the linear relationship indicated by △ Hq and △ εe '
A coefficient indicating the slope of △ εe ′ with respect to c ′: △ He in the linear relationship indicated by △ He and △ εq ′
D ': a coefficient indicating the slope of △ εq ′ with respect to △ Hq in the linear relationship indicated by △ Hq and △ εq'
E ′: the value of △ εe ′ when both △ He and △ Hq are zero f ′: the coefficient of △ εe ′ when both △ He and △ Hq are zero Value g ′: <W ₁ > in the linear relationship indicated by <W ₁ > and △ εe ′
_1> 'coefficient indicating the slope of the h' △ .epsilon.e for: <W _2> and △ .epsilon.e 'and <W in the linear relationship indicated
_2> 'coefficient indicating the slope of k' △ .epsilon.e for: <W _1> and △ Ipushironq 'and <W in the linear relationship indicated
_1> 'coefficient indicating the slope of m' △ εq for: <W _2> and △ Ipushironq 'and <W in the linear relationship indicated
After rolling is started by setting according to the coefficient indicating the slope of △ εq 'to ₂ >, the sheet thickness distribution in the sheet width direction on the rolling mill entry side, the sheet shape on the rolling mill exit side, and the sheet before reel winding Continuous measurement of the distribution of the passing position in the width direction and the elongation between the plate-side ends and between the quarters, corrected for the fluctuation in tension in the width direction caused by one crown during reel winding. The rate differences εe and △ εq, and the differences △ εe ′ and △ εq ′ between the elongation at the center of the sheet width, the average elongation at the side edges of both sides, and the average elongation at the quarters on both sides, respectively, are as follows: Dεe = −ln (LeW / LeD) dεq = −ln (LqW / LqD) dεe ′ = − ln (LeW / Lc) / 2−ln (LeD / L
c) / 2 dεq ′ = − ln (LqW / Lc) / 2−ln (LqD / L
c) / 2 △ εe = △ εe 2 -dεe △ εq = △ εq 2 -dεq △ εe '= △ εe 2' -dεe '△ εq' = △ εq 2 '-dεq' here, dεe: exits the rolling mill Dεq: Elongation difference corresponding to the tension fluctuation difference between the quarter parts dεe ′: Tension fluctuation at the center of the plate width and the plates on both sides Elongation difference dεq ′ corresponding to the difference in average tension fluctuation at the side end dεq ′: Elongation difference Lc, LeW, corresponding to the difference between the tension fluctuation at the center of the plate width and the average tension fluctuation at the quarters on both sides LqW, LeD, LqD: distances from the rolling mill to the reel winding position at the plate width center, the operation side plate side end, the operation side quarter portion, the drive side plate side end, and the drive side quarter portion, respectively. .epsilon.e _2: rolling mill stretching out index difference between the plate-side ends of the installation shape detector by directly obtained the delivery side of the rolling mill on the side △ εq _2: on the delivery side of the rolling mill Elongation difference between the delivery side of the rolling mill of the quota portions obtained directly by location shape detector △ .epsilon.e ₂ ': rolling mill exit was placed in side shape detector by the rolling mill outlet side of the plate width central obtained directly Difference between the elongation percentage and the average elongation percentage at both ends of the strip side Δεq ₂ ': The elongation percentage at the center of the strip width at the exit side of the rolling mill and the quarter on both sides directly obtained by the shape detector installed on the exit side of the rolling mill The difference between the average elongation rate of the part and the target values 伸 び Ee ₀ and △ Eq _{0 of the} difference in the elongation rate between the plate side ends and between the quarter parts, a target value of the difference between the respective average growth rate of the average growth rate and both quota portions △ Ee ₀ 'and △ Eq _0', the next four formula _{△ Ee 0 = △ εe 0 +} β × (△ εe 0 − △ εe) △ Eq ₀ = △ εq ₀ + β × (△ εq ₀ − △ εq) △ Ee ₀ '= △ εe ₀ ' + β × (△ εe ₀ '− △ εe') △ Eq ₀ '= △ εq ₀ '+ Β × (△ εq ₀ '- △ _εq') where, beta: by substituting each of the obtained by a factor used to adjust the correction equation (A) and (B), the control amount and the control of the symmetrical shape control section asymmetrical control term A shape control method in rolling of a single crown metal strip, characterized in that the sheet shape is controlled by setting while constantly correcting the amount.