JPH0623413A - Method for calculating forward slip of tandem mill - Google Patents

Abstract

PURPOSE:To determine forward slip at a prescribed stand even in the case where a speed meter with which the speed of a material to be rolled is measured is not utilized from the problem of installation environment or the like. CONSTITUTION:The forward slip fi at a i-th stand is determined by this method. The actual value VRi of roll speed and the actual value hi of thickness on the outlet side of the i-th stand are measured. In the step 104, a prescribed reference stand which is different from the i-th stand is taken. The actual value VRj of roll speed and the actual value hj of thickness on the outlet side of a j-th stand of which the forward slip fj is clarified are measured. In the step 106, the forward slip fj of the i-th stand is determined by mass flow rate constant law using the actual values VRi, VRj, of roll speed, actual values hi, hj of thickness on the outlet sides and forward slip fj. Then, it is unnecessary to use the actual value Vi of roll speed of the material to be rolled on the outlet side of the i-th stand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem rolling mill advanced rate calculation method for obtaining an advanced rate f _i of an ith stand of a tandem rolling mill having a plurality of rolling stands, and more particularly,
Even if a speedometer that measures the speed of the material to be rolled cannot be used due to problems such as the installation environment, the advanced rate of the specified i-stand
The present invention relates to a method for calculating an advanced rate of a tandem rolling mill capable of obtaining f _i .

[0002]

2. Description of the Related Art The classic Siebel friction of rolling theory
There is a general theory of Karman and Orowan that develops the theory of hill. Also, in order to set the appropriate rolling conditions during the operation of the rolling mill, these Karman and Orowan are set.
The theoretical formula of (1) is developed, and it is approximated to an automatically controllable one. In various rolling theories,
Alternatively, when rolling a predetermined material to be rolled through the contact parts of the upper and lower rolls in the operation of the rolling mill,
f is one of the important parameters.

In a general method of calculating the advanced rate, the actual speed value v is obtained by using a speedometer for measuring the traveling speed of the material to be rolled on the exit side of the rolling mill, and the actual speed value v of the rolling roll is calculated.
There is one that can be obtained by v _R and the following formula.

[0004] _{f = (v / v R)} -1 ... (1)

[0005]

However, in such an advanced rate calculation method, the actual velocity value v of the material to be rolled must be obtained in advance. For example, when it is impossible or difficult to install a speedometer that measures such actual speed value at a position where the desired actual speed value v can be measured due to problems such as installation space and installation environment. There is. Even if it can be installed, it may be difficult to detect the actual speed value v with sufficient accuracy due to problems such as the installation environment. For example, it is difficult to accurately obtain the actual speed value v with a speedometer using the laser Doppler method as a detection principle due to scattering of coolant or fumes between stands with a tandem rolling mill.
Further, since such a speedometer is relatively expensive, there are problems that the cost and maintenance load increase.

The present invention has been made in order to solve the above-mentioned conventional problems, and even when a speedometer for measuring the speed of a material to be rolled cannot be used due to a problem such as an installation environment, it is possible to set a predetermined value.
It is an object of the present invention to provide a method for calculating an advanced rate of a tandem rolling mill that can obtain an advanced rate f _i of an i stand.

[0007]

SUMMARY OF THE INVENTION The present invention provides a tandem rolling mill advanced ratio calculation method for obtaining an advanced ratio f _i of an i-th stand of a tandem rolling mill having a plurality of rolling stands. The actual speed value v _Ri and the actual _output plate thickness value h _i are measured, and further, it becomes a predetermined reference stand different from the i-th stand, and its advanced rate f _j is clear or is the reference j-th. The actual roll speed value v _{Rj of the} stand and the actual output plate thickness value h _j are measured, and based on the law of constant mass flow, the actual roll speed values v _Ri and v
_Rj , the output side plate thickness actual values h _i and h _j , and the advanced rate
The object is achieved by obtaining the advanced rate f _i of the i-th stand using f _j .

[0008]

According to the present invention, in obtaining the advanced rate f _i of the i-th stand of a tandem rolling mill having a plurality of rolling stands,
When the actual velocity value v _i of the rolled material on the exit side of the i-th stand cannot be obtained, only the actual value or parameter that can be normally obtained with the desired accuracy is used, and It was made focusing on calculating the advanced rate f _i .

[0009] When obtaining the forward slip f _i said i stand, even when the forward slip f _i can not be calculated from the equation (1), forward slip different from the first j stand and said i stand
Sometimes f _j is obvious. In many cases, it can be used as a reference even if it is not clear. In the present invention, when the advanced rate f _j of the j-th stand is clear or can be used as a reference in this way, the roll speed actual value v _Ri and the delivery side plate actual value of the i-th stand are based on the law of constant mass flow. By using h _i , and the actual roll speed value v _{Rj of} the j-th stand and the actual output plate thickness value f _j , the advanced rate of the i-th stand
I try to find f _i .

FIG. 1 is a flowchart showing the gist of the present invention.

In FIG. 1, first, at step 102, for the i-th stand corresponding to the advanced rate f _i to be obtained by the method for calculating the advanced rate of the tandem rolling mill according to the present invention, the actual roll speed value v _Ri and the output are obtained. Side plate actual value h
measure _i . Further, in step 104, the advanced ratio f of the predetermined reference stand, which is different from the i-th stand, is obtained.
_j measures the roll speed actual value v _Rj and delivery side thickness actual value h _j of the j stand to or reference has been revealed. The present invention does not limit the order of measurement of actual values in these steps 102 and 104, as long as all the actual values have been obtained by step 106 described below. The actual roll speed values v _Ri and v _Rj can be generally easily measured from, for example, a pulse generator or the like which is usually provided for controlling the roll speed of the corresponding stand. Further, even if the actual velocity value v _i of the material to be rolled cannot be measured by the i-th stand, it may be possible to measure the output side plate thickness actual value h _{i by the i-} th stand. The present invention can be applied.

In FIG. 1, step 106 is continued.
Then, based on the law of constant mass flow, using the actual roll speed values v _Ri and v _Rj , the actual output plate thickness values h _i and h _j , and the advanced rate f _j , the advanced rate of the i-th stand Find f _i . The present invention does not limit, for example, a calculation formula for obtaining such an advanced rate f _i ,
Based on the law of constant mass flow, these actual values v _Ri and v
It may be obtained by using _{R j} , h _i and h _j , or the advanced rate f _j .

[0013] Thus, according to the present invention, even such where applicable the i velocity actual value v _i of the stand forward slip f _i to be obtained is not available, it is possible to determine the forward slip f _i Is.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram of a cold tandem rolling mill to which this embodiment is applied.

As shown in FIG. 2, the cold tandem rolling mill is composed of a total of five rolling stands, and the steel sheet 1, which is the material to be rolled, is fed from left to right.
Each of the rolling stands has work rolls 51-51.
55, backup rolls 11 to 15, and electric motor 21
25 to 25 and pulse generators 31 to 35. In each of the rolling stands, the work rolls 51 to 51
55 and the backup rolls 11 to 15 are driven by the electric motors 21 to 25. At this time, the electric motor 21
~ 25 said pulse generator 3 attached
The roll speed calculation device 80 performs the speed control of the roll speed using 1 to 35.

Further, in the roll speed calculating device 80,
Of each work roll 51-55 of each rolling stand
Actual roll speed value v_Ri, V_Rj(I, j = 1-5, i ≠ j
 ) Is generated by the pulse generators 31-35.
It is calculated according to the pulse according to the roll speed.
Further, the roll speed calculation device 80 obtains in this way
The actual roll speed value of each rolling stand_Ri, V
_RjIs input to the process computer 82. The process
The calculator 82 stores these actual roll speed values v_Ri, V _RjWhen
In both cases, the exit side plate thickness is arranged behind each of the rolling stands.
Actual output side plate thickness h measured with a total of 41 to 45_i h_j(I
 , J = 1 to 5, i ≠ j), and the fifth stand at the final stage
Actual plate speed value from the plate speed meter 65 arranged behind v_FiveIs in
I will be forced.

The process calculator 82 obtains the advanced rate f ₅ at the fifth stand according to the actual plate speed value v ₅ and the actual roll speed v _{R5 of} the fifth stand and the following equation.

F ₅ = (v ₅ / v _R5 ) -1 (1a)

In the following, the actual roll speed values v _Ri and v _Rj and the actual output plate thickness value h _i based on the law of constant mass flow.
The calculation formula used by the process computer 82 for obtaining the advanced rate f _i of the i-th stand (i = 1 to 4) using h and h _j and the advanced rate f ₅ will be described.

First, according to the law of constant mass flow, the i-th stunt for which the advance rate is to be calculated and the advance rate f which is a predetermined reference stand different from the i-th stand are calculated.
_For the j-th stand where _j is clear, the following equation holds.

H _i · v _Ri · (1 + f _i ) = h _j · v _Rj · (1 + f _j ) ... (2)

In the cold tandem rolling mill, since the advance rate f ₅ of the fifth stand is clear from the equation (1a), if the j-th stand is the fifth stand, the above (2 Equation) can be transformed into the following equation.

[0024] _{h i · v Ri · (1+} f i) = h 5 · v R5 · (1+ f 5) ... (2a)

Further, by transforming the equation (2a), the i-th
We can obtain the following equation to obtain the stand advance rate f _i .

F _i = {(h ₅ · v _R5 ) / (h _i · v _Ri )} · (1 + f ₅ ) −1 (3a)

The formula (3a) can be expressed as the following formula by generalizing the stand whose advance rate f _j is clear as the j-th stand.

F _i = {(h _j · v _Rj ) / (h _i · v _Ri )} · (1 + f _j ) −1 (3)

In the present embodiment, the advanced rates f ₁ to f at the respective stands from the first stand to the fourth stand
₄ is calculated by the process computer 82 in accordance with the formula (3a). Further, in the process computer 82 of the present embodiment, in accordance with forward slip f ₅ obtained by the forward slip f ₁ ~ f ₄ obtained sequentially in this manner, and the (1a), used for the actual control of the rolling mill The advanced rate f _i ^A (k) is calculated by the adaptive correction calculation as shown in the following equation.

F _i ^A (k) = (1−α) · f _i ^A (k−1) + α · f _i (4)

In this equation (4), f _i ^A (k
) Is the current value of the advanced rate obtained by the adaptive correction, f _i ^A (k −1) is the previous value of the advanced rate obtained by the adaptive correction, and α is the adaptive correction gain (0 <α <1 )
Is. In the present example, at the time of setup calculation at the start of rolling operation, the preceding ratio previous value f _i ^A (k −
The value calculated by the advanced rate prediction model based on the rolling theory is used for 1).

In this embodiment, the plate speed meter 65 is installed on the outlet side of the fifth stand, and the measured plate speed actual value v ₅
Although the advanced rate f ₅ is obtained by the equation (1a) above, a value calculated by an advanced rate prediction model based on the rolling theory may be used as the advanced rate f ₅ .

FIG. 3 is a graph of off-gauge length showing the effect of this embodiment.

In FIG. 3, a laser Doppler plate speed meter is provided not only on the exit side of the fifth stand but also on the exit side of each of the first to fourth stands, and the advanced rate f ₁ to The off-gauge length in the conventional method when f ₅ is obtained and rolled is shown (unit: m 2). Also, this figure 3
In the present embodiment, that is, the advanced rates f ₁ ^A (k) to f ₅ ^A (k) using the equations (3) and (4) as the advanced rates of the first stand to the fourth stand, respectively. ) Is shown and the off-gauge length is shown (unit: m 2).

As shown in FIG. 3, according to the present embodiment, the off-gauge length can be reduced by about 20% as compared with the conventional method in combination with the adaptive correction shown in the equation (4). There is.

In this embodiment, the advanced rate f
_{Although the j-th} stand, which is the reference stand for which _j is clear, is the fifth stand, it goes without saying that the present invention is not limited to this.

[0037]

As described above, according to the present invention, even when a speedometer for measuring the speed of a material to be rolled cannot be used due to a problem such as an installation environment, the advanced rate f of a given i-th stand can be improved.
An excellent effect that _i can be obtained can be obtained. Further, even if the speedometer can be installed technically, according to the present invention, it can be omitted, for example, and in this case, the effect of cost reduction and maintenance load reduction can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing the gist of the present invention.

FIG. 2 is a configuration diagram of a cold tandem rolling mill to which this embodiment is applied.

FIG. 3 is a graph of off-gauge length showing the effect of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rolled material (steel plate) 11-15 ... Backup roll 21-25 ... Electric motor 31-35 ... Pulse generator 41-45 ... Delivery side plate thickness gauge 51-55 ... Work roll 65 ... Plate speed meter (velocimeter) 80 ... Roll speed calculator 82 ... Process calculator

Claims (1)

[Claims] 1. A method for calculating an advanced rate of a tandem rolling mill, which obtains an advanced rate f _i of an i-th stand of a tandem rolling mill having a plurality of rolling stands, comprising: an actual roll speed value v _{Ri of} the i-th stand and a delivery plate. The actual thickness value h _i is measured, and further, the roll speed actual value v _{Rj of} the j-th stand, which is a predetermined reference stand different from the i-th stand and whose advance rate f _j is clear or is the reference And the actual value h _j of the outlet plate thickness are measured, and the actual roll speed value v
_Ri and v _Rj , the output side strip thickness actual values h _i and h _j , and the advanced rate f _j are used to determine the advanced rate f _i of the i-th stand, and the advanced rate of the tandem rolling mill is characterized. Calculation method.