JP3506079B2 - Roll eccentricity detection method and sheet thickness control method - 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 detecting the amount of eccentricity of a backup roll of a rolling mill and a method for controlling the thickness of a metal sheet such as a steel sheet being rolled using the method.

[0002]

2. Description of the Related Art In a rolling mill used for rolling a metal sheet such as a steel sheet, a variation in the roll gap caused by an eccentricity of a backup roll causes a variation in the thickness of a certain period, and a generally used automatic thickness The controller cannot remove the plate thickness variation due to the eccentricity of the backup roll.
Therefore, for example, JP-A-5-3 previously proposed by the applicant
As described in Japanese Patent No. 17944, a backup roll eccentricity removal plate thickness control applying Fourier series expansion has been developed. In this plate thickness control method, prior to rolling, the eccentric amount of the backup roll is estimated from the fluctuation of the rolling load in the kiss roll state, and the eccentric amount of the backup roll is removed from the roll gap correction amount during rolling. ,
I try to adjust the roll gap.

[0003]

However, in the conventional backup roll eccentricity amount detection method and the plate thickness control method based on the conventional backup roll eccentricity amount detection method, the eccentricity amount of the backup roll can be detected only before rolling. There is a problem that the eccentricity amount of the backup roll or its change due to expansion or wear cannot be detected, and therefore the plate thickness cannot be accurately controlled by correcting the eccentricity amount of the backup roll.

The present invention was developed to solve the above problems, and it is possible to detect the amount of eccentricity of a backup roll during actual rolling or between rollings, and at the same time, use it to accurately measure An object of the present invention is to provide a roll eccentricity amount detection method and a plate thickness control method capable of controlling the plate thickness.

[0005]

In order to solve the above problems, a roll eccentricity detection method according to claim 1 of the present invention is a method for detecting the eccentricity of a backup roll of a rolling mill. It is characterized in that the amount of disturbance of the roll gap is obtained according to the gauge meter formula using the load during rolling, the roll gap and the plate thickness on the delivery side of the rolling mill, and the amount of eccentricity of the backup roll is calculated from the amount of disturbance of the roll gap. It is what

Further, a plate thickness control method according to a second aspect of the present invention is a method for controlling a plate thickness rolled by a rolling mill, which comprises a load during rolling, a roll gap, and a plate thickness on the delivery side of the rolling mill. Determine the amount of disturbance of the roll gap according to the gauge meter formula using, calculate the amount of eccentricity of the backup roll from this amount of disturbance of the roll gap, and remove the amount of eccentricity of the backup roll from the correction amount of the roll gap during rolling. It is characterized in that the roll gap is adjusted using the value.

The thickness of the gauge meter type is
It is a relational expression expressed by the sum of the rolling load divided by the mill constant, the set roll gap, and the amount of disturbance in the roll gap when there is a disturbance. The set plate thickness is expressed by the sum of the rolling load divided by the mill constant and the set roll gap. Therefore, the amount of disturbance of the roll gap can be obtained by subtracting the latter and the set plate thickness from the former and the actual plate thickness. Further, as a means for calculating the eccentricity amount of the backup roll from the disturbance amount of the roll gap, the disturbance amount of the roll gap, for example, by Fourier series expansion, a component corresponding to the rotation cycle of the backup roll, that is, backup. The amount of eccentricity of the roll can be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a rolling mill that embodies the roll eccentricity amount detection method and the plate thickness control method of the present embodiment. Reference numerals 1a and 1b in the drawing denote a pair of upper and lower work rolls, and reference numerals 2a and 2b denote a pair of upper and lower backup rolls. The rotation angles θ _t and θ _b of the backup rolls 1a and 1b are detected by the rotation angle detectors 3a and 3b, respectively, and output to the roll eccentricity amount detector 7 and the roll gap correction device 9. Further, the rolling load P is detected by the load detector 4, the roll gap S is detected by the roll gap detector 5, and the plate thickness h is detected by the plate thickness detector 6, respectively, and output to the roll eccentricity detector 7. . The roll gap correction device 9 uses the logic described below to detect the eccentricity amounts S _Rt (θ _t ) and S _{Rb of} the backup rolls 2a and 2b detected by the roll eccentricity amount detector 7.
(Θ _b ) is subtracted from the AGC roll gap correction amount ΔS _AGC obtained by the automatic plate thickness controller (AGC) 8 to obtain the corrected roll gap correction amount ΔS, which is output to the roll gap adjuster 10. To do. And
The roll gap adjuster 10 adjusts the roll gap S of the work rolls 1a and 1b by an amount corresponding to the roll gap correction amount ΔS. The automatic plate thickness control device 8 sets the AGC roll gap correction amount ΔS _AGC by dividing the negative value of the rolling or the secondary fluctuation ΔP by the mill constant M regardless of the eccentricity amount of the backup rolls 2a and 2b. To do.

Next, the eccentricity S of the backup rolls 2a and 2b performed by the roll eccentricity detector 7 is performed.
_{The Rt} (θ _t ) and S _Rb (θ _b ) calculation logic will be described. For example, _assuming that the disturbance amount of the roll gap including the eccentricity of the backup rolls 2a and 2b is S _dis , the gauge meter formula for _obtaining the strip thickness on the _delivery side of the rolling mill is the actual strip thickness h, rolling load P, mill constant M. , With respect to the set roll gap (roll opening) S, it appears as in the following formula 1.

H = P / M + S + S _dis (1) On the other hand, the set plate thickness t _c is similarly expressed by the following two equations. h _c = P / M + S (2) Therefore, the following 3 expressions are obtained by subtracting 2 expressions from 1 expression. h−h _c = S _dis (3) FIG. 2a shows the set plate thickness h _c , and FIG. 2b shows the actually measured plate thickness h. The value obtained by subtracting the set value from the measured value, that is, the roll gap disturbance amount S _dis is shown in FIG. 2c. This roll gap disturbance amount S _dis contains noise in addition to the eccentricity amount of the backup rolls 2a and 2b, so this is expanded by Fourier series to rotate the backup roll as shown in FIG. 2c. Only the component corresponding to the cycle is extracted. The following four equations are Fourier series expansions based on the rotation angle θ _t of the upper backup roll 2a. It should be noted that A ₀ in the equation represents a drift superimposed component.

[0011]

[Equation 1]

Of these, the roll eccentricity component S _R (θ _t )
Is extracted as a component corresponding to the rotation cycle of the upper backup roll 2a, and the following five equations are obtained. S _R (θ _t ) = A ₁ cos θ _t + B ₁ sin θ _t (4) The above operation is performed by, for example, the upper and lower backup rolls 2a, 2
When the phase of b is deviated a plurality of times, at least two roll eccentricity amounts S _RI (θ _t ) and S _RII (θ _t ) are obtained as in the following formula 5.

S _RI (θ _t ) = A _I cos θ _t + B _I sin θ _t S _RII (θ _t ) = A _II cos θ _t + B _II sin θ _t (5) These two data and roll eccentricity S _RI (θ _t ), S _RII
Upper backup roll 2a when (θ _t ) was collected
Of the phase of the lower backup roll 2b based on α
Is given by the following equation 6.

Α = θ _bII −θ _bI (6) Then, due to the relationship of the Fourier series shown in FIG. 3, the eccentricity amounts S _Rt (θ _t ) of the upper and lower backup rolls 2a and 2b,
S _Rb (θ _b ) is expressed by the following 7 equations. S _Rt (θ _t ) = a cos θ _t + b sin θ _t (7) S _Rb (θ _b ) = c cos θ _b + d sin θ _b

[0015]

[Equation 2]

Therefore, in the roll gap correction device 9, the eccentricity amount S _Rt (θ _{t of the} upper and lower backup rolls 2a and 2b is calculated from the AGC roll gap correction amount ΔS _AGC calculated by the automatic plate thickness control device 8. ), S _Rb (θ _b )
Can be subtracted to calculate the true roll gap correction amount ΔS in which the roll eccentricity amount is corrected. Note that the plate thickness fluctuation and skid marks on the entry side appear as fluctuations in the rolling load, but with this roll eccentricity amount detection method and the plate thickness control method by roll gap correction, a calculation formula is used when calculating the roll eccentricity amount. Since the load P does not substantially participate from the inside, an accurate roll eccentric amount can be detected regardless of them, that is, regardless of the variation of the entrance side plate thickness and the skid mark.

[0017]

As described above, according to the roll eccentricity amount detecting method according to the first aspect of the present invention, the gauge meter uses the load during rolling, the roll gap and the strip thickness on the delivery side of the rolling mill. Obtaining the disturbance amount of the roll gap according to the formula, since it was decided to calculate the eccentric amount of the backup roll from the disturbance amount of the roll gap, it is possible to detect the eccentric amount of the backup roll during rolling or between rolling, It is possible to detect the amount of eccentricity of the backup roll due to thermal expansion and wear of the roll during rolling.

According to the plate thickness control method of the second aspect of the present invention, the disturbance amount of the roll gap is calculated according to the gauge meter formula using the load during rolling, the roll gap and the plate thickness on the delivery side of the rolling mill. Obtained, to calculate the eccentric amount of the backup roll from the disturbance amount of the roll gap, to adjust the roll gap by using the value obtained by removing the eccentric amount of the backup roll from the correction amount of the roll gap during rolling. Since the amount of eccentricity of the backup roll can be detected during rolling or between rolling, it is possible to detect the amount of eccentricity of the backup roll due to thermal expansion and wear of the roll during rolling, and using them It becomes possible to perform accurate control of the thickness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a rolling mill that embodies a roll eccentricity amount detection method and a plate thickness control method of the present invention.

FIG. 2 is an explanatory diagram of a logic of the roll eccentricity amount detected by the roll eccentricity amount detector of FIG.

FIG. 3 is a relationship diagram of Fourier series.

[Explanation of symbols]

1a and 1b are work rolls 2a and 2b are backup rolls Rotation angle detectors 3a and 3b 4 is a load detector 5 is a roll gap detector 6 is a plate thickness detector 7 is a roll eccentricity detector 8 is an automatic plate thickness control device 9 is a roll gap correction device 10 is a roll gap adjuster

Claims (2)

(57) [Claims] 1. A method for detecting the amount of eccentricity of a backup roll of a rolling mill, wherein the amount of disturbance of the roll gap is calculated according to a gauge meter method using the load during rolling, the roll gap and the plate thickness on the delivery side of the rolling mill. A roll eccentricity detection method, which comprises obtaining and calculating the eccentricity of the backup roll from the disturbance amount of the roll gap. 2. A method of controlling the strip thickness rolled by a rolling mill, wherein the disturbance amount of the roll gap is determined according to a gauge meter formula using the load during rolling, the roll gap and the strip thickness on the delivery side of the rolling mill, An eccentric amount of the backup roll is calculated from the disturbance amount of the roll gap, and the roll gap is adjusted using a value obtained by removing the eccentric amount of the backup roll from the correction amount of the roll gap during rolling. Plate thickness control method.