JP2013220454A - Method and device for setting up rolling speed of cold rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessively decelerated rolling operation by increasing a rolling speed upper limit value while rolling a current rolled material, coping with a change in friction coefficient even under a condition in which the friction coefficient greatly varies as in the first coil after a work roll change to improve rolling efficiency without generating trouble such as heat streaks or chattering.SOLUTION: A rolling speed upper limit value to be within upper and lower limit values of a previously set friction coefficient not generating heat streaks and chattering before rolling is started is set, rolling actual values of the friction coefficient varying during rolling at the set rolling speed upper limit value are collected, calculation of the rolling speed upper limit value is again performed so as to be within the upper and lower limit values of the previously set friction coefficient not generating heat streaks and chattering of a rolled material based on the friction coefficient during rolling, and rolling is performed at the rolling speed upper limit value exceeding a speed which has been last precedingly set up before the rolling is started or during rolling.

Description

  The present invention relates to a rolling rolling speed setup method and apparatus for cold rolling. For example, the rolling of the current rolled material is performed in response to the change in the friction coefficient even under a condition in which the friction coefficient varies greatly, such as the first coil of the work roll change. Rolling speed setup method for cold rolling that can increase rolling efficiency without increasing troubles such as heat streak and chattering by increasing the upper limit of rolling speed and preventing rolling operations that are decelerated more than necessary. And an apparatus.

  In a cold rolling line as illustrated in FIG. 1, a rolled material (also referred to as a coil) 10 delivered from a plurality of payoff reels 12 (two in the figure) on the line entry side is subjected to previous rolling by a welding machine 14. After being welded to the material and rolled by the tandem rolling mill 20 through the entry-side looper 16 and the like, it is wound up by, for example, a carousel type tension reel (referred to as a carousel reel) 22.

  In such a continuous cold rolling by the tandem rolling mill 20, since the rolled material 10 is not a single material, it may be necessary to change the rolling conditions, particularly the plate thickness, during the rolling. Even in such a case, the rolling operation is not interrupted, so the plate thickness is changed between runs, but when such a running plate thickness is changed, the surface temperature of the rolled material 10 increases excessively, and heat streak occurs. May cause surface wrinkles or chattering due to slips or sticks.

  Therefore, in Patent Document 1, before starting the rolling of the current rolled material (coil), it is a rollable region that does not generate heat streak or chattering as exemplified in FIG. It is proposed to set up the rolling speed to an upper limit value that is within the value, collect the rolling results during the rolling of the current rolled material, and perform the setup calculation of the next rolled material (coil) as shown in FIG. ing.

Japanese Patent Laid-Open No. 11-57828

  However, in the method described in Patent Document 1, the fluctuation of the friction coefficient due to the rolling distance is not taken into consideration during the rolling of one coil as illustrated in FIG. 4, and the rolling set before the rolling is started. In order to continue rolling at the upper speed limit, for example, under conditions where the coefficient of friction is large, such as the first coil of the work roll change, the coefficient of friction decreases as the rolling distance increases, causing problems such as heat streak and chattering. Despite the situation where a high rolling speed that does not occur is possible, rolling was performed at a lower rolling speed upper limit set in the setup before the start of coil rolling. As a result, the reduction rolling operation was more than necessary, and the rolling time was longer than necessary, and the efficiency was lowered.

  The present invention has been made to solve the above-mentioned conventional problems. For example, even in a condition where the friction coefficient greatly fluctuates such as the first coil of the work roll change, An object of the present invention is to increase the rolling speed upper limit during rolling to prevent undesired slow rolling operation and to improve rolling efficiency without causing troubles such as heat streak and chattering.

  The present invention sets a rolling speed upper limit value that falls within the upper and lower limits of a preset friction coefficient that does not cause heat streak or chattering before the start of rolling in setting up the rolling speed of cold rolling. The actual rolling value of the friction coefficient that varies during rolling at the upper limit of the speed is collected, and within the upper and lower limits of the preset friction coefficient that does not cause heat streaks and chattering of the rolled material based on the friction coefficient during the rolling. Thus, the above-mentioned problem is solved by recalculating the rolling speed upper limit and rolling at a rolling speed upper limit equal to or higher than the speed set up before the start of rolling or one before rolling.

  Here, learning calculation is performed using the rolling actual value of the friction coefficient obtained during rolling at the rolling speed upper limit value derived by the setup recalculation, and the rolling speed upper limit value of the next rolling material can be set. .

  The present invention also includes means for setting a rolling speed upper limit value that is within the upper and lower limit values of a preset friction coefficient that does not generate heat streak or chatter before the start of rolling, and rolling at the set rolling speed upper limit value. Rolling means so as to be within the upper and lower limits of the preset friction coefficient that does not cause heat streaks and chattering of the rolled material based on the means of collecting the actual rolling friction coefficient value and the friction coefficient during the rolling Cold rolling rolling characterized by comprising means for recalculating the speed upper limit and means for rolling at a rolling speed upper limit equal to or higher than the speed set up before the start of rolling or one before rolling. A speed setup device is provided.

  Here, learning calculation is performed using the rolling actual value of the friction coefficient obtained during rolling at the rolling speed upper limit value derived by the setup recalculation, and a means for setting the rolling speed upper limit value of the next rolling material is provided. be able to.

  According to the present invention, since the setup of the current rolled material is recalculated according to the rolling record collected during rolling, for example, even under conditions where the friction coefficient fluctuates greatly, such as the first roll of the work roll, The upper limit of the rolling speed set before the start of rolling is not persisted, and the upper limit of the rolling speed is increased during the rolling of the current rolling material in response to the change in the friction coefficient, preventing unnecessary slow rolling operations. Thus, without causing troubles such as heat streak and chattering, the rolling efficiency can be improved, the rolling time can be greatly shortened, and the power unit and the rolling oil unit can be improved.

Process drawing which shows the whole structure of an example of the cold rolling line to which this invention is applied The figure which shows the example of the relationship between the rolling speed and the friction coefficient in the conventional setup method described in patent document 1 Same time chart Diagram showing an example of the relationship between rolling distance and coefficient of friction The flowchart which shows the setup method of the rolling-speed upper limit in embodiment of this invention. The figure which similarly shows the example of the relationship between rolling speed and friction coefficient A time chart showing a setup method in an embodiment of the present invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 5 shows a setup processing procedure in the embodiment of the present invention.

First, in step 100, setup before starting rolling is performed. Specifically, the rolling speed upper limit A illustrated in FIG. 6 is set using the same prediction formula before rolling as that in FIG. The friction coefficient μi used at this time is set by the following equation.
μi = μ1i · Ui (1)

  Here, Ui is a reference table value at the reference speed immediately after the roll change.

μ1i is a friction coefficient correction term by the rolling speed (μ1i = 1 at the reference speed Vi = ∞). For example, the following expression μ1i = 1 + a1 _i e ^{−b1i · Vi} (2)
It is represented by However, a1 _i and b1i are rolling speed correction coefficients (fixed values).

  Next, in step 110, rolling of the current coil is started.

  Next, at step 120, when it is determined that the friction coefficient has changed, for example, when the rolling distance reaches a predetermined value, at step 130, actual rolling values (load, tension) are collected.

Next, in step 140, setup recalculation is performed using the rolling record value collected in step 130, the upper limit value of the rolling speed of the current coil is reset, and the speed is increased. Specifically, the rolling speed upper limit value B is determined using the recalculation prediction formula illustrated in FIG. The friction coefficient μi used at this time is set by the following equation.
μi = μ1i · μ2i · Ui (3)

Here, μ2i is a friction coefficient correction term by the rolling distance as exemplified in FIG. 4 (μ2i = 1 at the rolling distance Lri = ∞). For example, the following expression μ2i = 1 + a2 _i e ^{−b2i · Lri} (4)
It is represented by However, a2 _i and b2i are rolling distance correction coefficients (fixed values).

  In this way, it is possible to increase the rolling speed from the rolling speed upper limit A of the prediction formula before rolling start shown in FIG. 6 to the rolling speed upper limit B of the recalculation prediction formula.

Further, when it is determined in step 150 that the time to set up the next coil has been reached, for example, when the current coil is removed from the payoff reel 12, the process proceeds to step 160 to set up the next coil. Specifically, for example, the friction coefficient μi is calculated by the following equation.
μi = μ0Hi, μ1i, μ2i, Ui (5)

Here, μ0Hi is a learning coefficient related to the rolling distance by exponential smoothing learning, and is calculated by the following equation.
μ0Hi = (1−α) μa + α × μb (6)

  Here, μa is the previous value of the friction coefficient correction coefficient, μb is the current value of the friction coefficient correction coefficient, α is an exponential smoothing coefficient (0 ≦ α ≦ 1), and the closer to 1, the better the followability.

  Note that the initial value of the learning coefficient μ0Hi can be 1.

  The state of the setup calculation in this embodiment is shown in FIG.

  Note that the timing of recalculation in one coil is not limited to once, but may be performed several times at regular intervals, for example.

  In addition, the setup recalculation is not limited to the first coil after the work roll is changed. As in the example shown in FIG. 7, the recalculation is performed up to the second coil, for example, several coils to further increase the rolling speed. It is possible to go.

10 ... Rolled material (coil)
DESCRIPTION OF SYMBOLS 12 ... Payoff reel 14 ... Welding machine 16 ... Entry looper 20 ... Tandem rolling machine 22 ... Carozel reel

Claims (4)

Set the rolling speed upper limit value that is within the upper and lower limits of the friction coefficient set in advance that does not cause heat streak or chattering before the start of rolling,
Collect the rolling performance value of the friction coefficient that fluctuates during rolling at the set rolling speed upper limit,
Based on the friction coefficient during the rolling, the calculation of the rolling speed upper limit value is performed again so that it is within the upper and lower limit values of the preset friction coefficient that does not generate heat streaks and chattering of the rolled material,
A rolling speed set-up method for cold rolling, characterized in that rolling is performed at a rolling speed upper limit value equal to or higher than the speed set up before the start of rolling or one before rolling.   Performing learning calculation using the rolling actual value of the friction coefficient obtained during rolling at the rolling speed upper limit value derived by the set-up recalculation according to claim 1, and setting the rolling speed upper limit value of the next rolling material. A rolling speed setup method for cold rolling. Means for setting a rolling speed upper limit value that is within the upper and lower limit values of a preset friction coefficient that does not cause heat streak and chattering before the start of rolling;
Means for collecting a rolling performance value of a friction coefficient that varies during rolling at the set rolling speed upper limit;
Based on the friction coefficient during the rolling, means for performing again the calculation of the rolling speed upper limit value so as to be within the upper and lower limit values of the friction coefficient that does not generate heat streaks and chattering of the rolled material,
Means for rolling at a rolling speed upper limit equal to or higher than the speed set up before the start of rolling or one before rolling;
A rolling speed set-up device for cold rolling.   Means for performing learning calculation using the rolling actual value of the friction coefficient obtained during rolling at the rolling speed upper limit value derived by the set-up recalculation according to claim 3, and setting the rolling speed upper limit value of the next rolling material A rolling speed set-up device for cold rolling, comprising:

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