JPH10244304A - Continuous rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous rolling method which controls the roll circumference speed of a 1st stand precisely corresponding even to the tension variation when the connecting point is passed through the 1st stand without adding the restriction to the rolling reduction ability of the rolling mill of the 1st stand. SOLUTION: A 2nd controller 2 reads forward slips fci-1 , fci given from a 1st controller 1 in a proper timing, and which reads the detecting results of thickness meters 7, 7 and the calculated result of a circumference speedometer 8 installed on a 1st stand #1, based on these data, which calculates the circumference speed Vi-1 of work rolls 10, 10 provided in a (i-1) stand #(i-1), which gives them to the circumference speed controller 5 of a (i-1) stand #(i-1) and which regulates the rotation drive of a motor M so that it is made in the calculated circumference speed Vi-1 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a continuous rolling mill in which a plurality of stands are arranged in tandem.
The present invention relates to a method of continuously rolling while changing the thickness of a target material to be rolled.

[0002]

2. Description of the Related Art In continuous rolling, in which the thickness of a material to be rolled is changed during continuous rolling, a plurality of materials having the same or different sizes are connected to each other. The rolling material is continuously rolled by changing the rolling position of the rolling device provided in the stand and the peripheral speed of the rolling roll at the timing when the connection point is fed to the mill. In such rolling, it is important to maintain a mass flow balance and reduce the fluctuation in tension.

For this reason, the following rolling method is disclosed in Japanese Patent Application Laid-Open No. 6-15317. Tracking the connection point between the preceding material and the succeeding material, and immediately before the connection point reaches the i-th stand, giving the target exit side thickness of the following material to the control device that controls the rolling of the i-th stand. The target outlet thickness of the preceding material is changed to the target outlet thickness of the succeeding material within a fixed time after the connection point reaches the i-th stand.

[0004] The control device is provided with the actual values of the rolling load and the rolling position of the rolling device provided on the i-th stand. The estimated exit thickness of the material to be rolled at the i-th stand is calculated by substituting into the equation, and a thickness deviation which is a difference between the target exit thickness and the estimated exit thickness is obtained. The lowering position of the i-th stand is adjusted so that

The control device stores the estimated outlet thickness of the i-th stand calculated over time, and stores the estimated thickness on the (i +) th stand.
1) Identify the past estimated outlet thickness for the time required for the material to be rolled to the stand and make it the estimated inlet thickness of the (i + 1) th stand. The control device is connected to the (i +
1) Stand-side thickness change rate of the stand, (i + 1) th stand-out thickness change rate, i-th stand advanced rate change rate, (i + 1) stand advanced rate change rate, and (i + 1) th advanced rate change rate
Each of the stand control amounts is calculated, and the roll peripheral speed change amount of the i-th stand is calculated using the calculation result, and the roll peripheral speed of the i-th stand is changed so as to become the obtained roll peripheral speed change amount. I do. As a result, the outlet speed of the i-th stand of the material to be rolled and the inlet speed of the (i + 1) -th stand become equal, and the i-th stand and the (i +
1) The fluctuation of the tension of the material to be rolled between the stand and the stand is suppressed,
In addition, the mass flow balance is maintained.

[0006]

In the conventional method, in order to reduce the fluctuation in tension, the connection between the material to be rolled on the downstream stand and the material to be rolled on the thicker upstream stand is not required. Within the same time after the point reaches the stand, the target delivery thickness of the preceding material is changed to the target delivery thickness of the succeeding material. However, when the rolling capacities of the respective stands are the same, the time required for changing the rolling position of the rolling device of the stand having a thin material to be rolled can be shorter than that of the rolling device of the stand having a thick material to be rolled. That is, in the conventional method, the rolling capacity of the rolling device of the stand where the material to be rolled is thin is limited, and the target exit side thickness cannot be changed in a shorter time. There is a problem that an off-gauge is generated at a position where the thickness is changed.

In addition, the estimated thickness of the (i + 1) -th stand is used for calculating the roll peripheral speed change amount of the i-th stand. This is the estimated thickness on the outlet side of the i-th stand, which is traced back by the time required to transfer the material to be rolled, and it is difficult to obtain this time with high accuracy. Was also low. Further, when the connection point passes through the i-th stand, the thickness of the material to be rolled, the rolling load of the i-th stand, and the advance rate change greatly, so that a large tension variation occurs in the material to be rolled. The conventional method for determining the estimated entrance thickness of the (i + 1) th stand from the estimated exit thickness of the i-th stand cannot cope with this tension variation.

The present invention has been made in view of such circumstances, and an object of the present invention is to change a rolling position of a rolling roll of each stand on the basis of a corresponding advancement rate, and to change the position of two adjacent rolls. The thickness of the material to be rolled on the outlet side of each stand is determined, the peripheral speed of the rolling roll provided on the downstream stand of both stands is detected, and the detected peripheral speed, the determined thicknesses and the determined thicknesses are determined. By calculating the adjustment amount of the peripheral speed of the rolling roll provided on the upstream stand based on the advance rate at the stand, and adjusting the peripheral speed of the rolling roll of the upstream stand, the rolling device of each stand is calculated. Provided is a continuous rolling method capable of controlling the roll peripheral speed of the upstream stand with high accuracy in response to tension fluctuation when the connection point passes through each stand without limiting the rolling capacity of the stand. This Located in.

[0009]

SUMMARY OF THE INVENTION A continuous rolling method according to the present invention comprises feeding a material to be rolled to a continuous rolling mill in which a plurality of stands having rolling rolls are arranged in tandem. In the method of rolling while changing the length between runs, based on the target thickness of the material to be rolled, the advance rate of the material to be rolled at each stand and the rolling position and peripheral speed of the rolling roll are calculated in advance, and While changing the rolling position and peripheral speed of the rolling roll of the stand at a predetermined timing,
The thickness of the material to be rolled on the outlet side of each of the two adjacent stands is determined, and the peripheral speed of the rolling roll provided on the downstream stand is detected. And the amount of adjustment of the peripheral speed of the rolling roll provided in the upstream stand is calculated and adjusted based on the advance rate at both stands.

[0010] In the continuous rolling method of the present invention, each stand provided in the continuous rolling mill is provided for each target thickness of the material to be rolled, based on information such as the thickness and the type of steel and a calculation model obtained in advance. In advance, the advance rate of the material to be rolled, the rolling position of the rolling roll, and the peripheral speed are determined. When a plurality of materials to be rolled are connected, different thicknesses are obtained at a timing immediately before the connection point reaches the stand or at a time when the connection point reaches the stand, and at a predetermined position in the longitudinal direction for one material to be rolled. In the case of changing the rolling position or peripheral speed at the timing immediately before the predetermined position reaches the stand or at the timing when the predetermined position reaches the stand, the rolling position and the peripheral speed of the rolling roll provided in each stand are changed. The above-mentioned timing is obtained by calculation based on the transfer speed of the rolling roll, and the rolling position and the peripheral speed of the rolling roll of each stand are sequentially changed at each obtained timing.

On the other hand, the thickness of the material to be rolled at an adjacent stand is obtained as an actual measurement value or a gauge thickness, and the peripheral speed of a rolling roll provided on a downstream stand of both stands is detected. Substituting the detected peripheral speed, the determined thickness and the advanced ratio corresponding to the rolling position of both stands into the following equation (1) to adjust the peripheral speed of the rolling roll provided in the upstream stand. The amount is calculated, and the peripheral speed of the rolling roll provided on the upstream stand is adjusted so as to be the calculated adjustment amount. _{V i-1 = {(1} + fc i) / (1 + fc i-1)} · (h i / h i-1) · V i ... (1) where, h _i: thickness of the material to be rolled on the downstream side stand h _(i-1): the thickness of the material to be rolled at the upstream stand V _i: the circumferential speed of the rolling rolls of the downstream stands V _i-1: peripheral speed of the rolling rolls of the upstream stand

As is apparent from the equation (1), mass flow balance can be maintained while absorbing fluctuations in the advance rate and thickness in both stands, and fluctuations in tension can be suppressed. Can respond to sudden fluctuations in tension that occur in In addition, since it is not necessary to change the rolling position of each stand within the same time, even if the changing time of the rolling position is set to be the shortest time according to the capability of the rolling device, the tension variation is minimized. The off-gauge can be reduced, and the off-gauge can be shortened. Further, the thickness of the material to be rolled at the upstream stand and the downstream stand, using the detected value of the peripheral speed of the rolling roll provided in the downstream stand, to determine the peripheral speed of the rolling roll of the upstream stand, The peripheral speed of the rolling roll of the upstream stand can be controlled with high accuracy.

[0013]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing a part of a continuous rolling mill used for carrying out the present invention and a control system thereof. FIG. 2 is a flowchart showing a control procedure of the first control device 1 shown in FIG. 1, and FIG. 3 is a flowchart showing a control procedure of the second control device 2 shown in FIG. The following material S _B preceding material and S _F is the material to be rolled are connected by a connecting point P, and is transferred respectively to the arrow direction. A pair of work rolls 10 and
(I-1) th stand provided with a pair of backup rolls 11 supporting the work rolls 10;
(I-1) is arranged. (I-1) Stand II
Downstream of (i-1), the (i-1) th stand (i-
The i-th stand #i is arranged at a predetermined distance from 1), and the i-th stand #i is also a work roll 10,
And backup rolls 11 and 11.

The (i-1) -th stand # (i-1) and the i-th stand #i are provided with pressing devices 4, 4 for changing the positions of the work rolls 10, 10, 10, 10, respectively. The rolling-down operation of the devices 4 and 4 is controlled by the rolling-down control devices 3 and 3, respectively. In addition, the (i-
1) The work rolls 10, 10, 10, 10 of the stand # (i-1) and the i-th stand #i are connected with motors M, M for rotating them, and the motors M, M control the peripheral speed. The rolls are controlled by the devices 5 and 5 so that the required roll peripheral speed is obtained.

First control for controlling the rolling operation of the continuous rolling mill
The device 1 has a preceding material S_F, Trailing material S _BSteel type, size, pressure
The rolling capacity and mill stiffness of the lower units 4 and 4 are given in advance.
The first control device 1 stores the data and the
Each stand モ デ ル (i-
1), target thickness at ♯i, advance rate fc_i-1, F
c_i, Rolling position, work roll peripheral speed and rolling position change
A further minimum time is calculated (step S1). Preceding material S_F
And trailing material S_BIs connected to a tracking device (not shown).
)) And the tracking device
The connection point P is set at each stand $ (i-1), $ i.
At the respective timings, the first controller 1 is triggered.
give. The first control device 1 determines whether a trigger has been given
Is determined (step S2).
Via a second control device 2 which controls the variation associated with the thickness change
And the corresponding stand # (i-1), #i
Commands to the units 3 and 3 and the peripheral speed controllers 5 and 5 (step
Step S3), the pressing position of the pressing devices 4, 4 and the motor M,
While changing the rotation speed of M, the changed stand.
(I-1), advanced rate fc of ♯i_i-1, Fc_iThe second control
It is given to the device 2 (step S4).

At the exit side of the (i-1) th stand # (i-1) and the i-th stand #i, thickness gauges 7, 7 for detecting the thickness of the material to be rolled are provided. The detection results detected by the thickness gauges 7, 7 are given to the second control device 2. (I-1)
The motors M, M provided in the stand # (i-1) and the i-th stand #i detect the rotational speeds of both motors M, M, and detect the rotation speed of the work rolls 10, 10, 10, 10, 10 from the detected values. The peripheral speed meters 8, 8 for calculating the peripheral speed are provided, respectively, and the calculation results of the peripheral speed meters 8, 8 are given to the second control device 2 via the peripheral speed control devices 5, 5.

The second control device 2 controls the advance rates fc _i-1 and fc _i provided by the first control device 1 at the above-mentioned timing.
Is read (step S11). Also, the second control device 2
Reads the detection results of the thickness gauges 7, 7 and the calculation results of the peripheral velocity meter 8 provided in the i-th stand #i (step S
12) Substituting the data into the following equation (2) to calculate the peripheral velocity Vi _-1 of the work rolls 10, 10 provided in the (i-1) th stand ♯ (i-1). (Step S13),
This is given to the (i-1) th stand # (i-1) peripheral speed control device 5 (step S14), and the calculated peripheral speed Vi _-1
The rotational drive of the motor M is adjusted so that _{V i-1 = {(1} + fc i) / (1 + fc i-1)} · (h i / h i-1) · V i ... (2) where, h _i: thickness of the rolled material in the i stand h _(i-1): (i-1) th thickness V _i of the material to be rolled at the stand: peripheral speed of work roll of the i stand

Thus, the (i-1) th stand♯
The peripheral speed of the work rolls 10 and 10 of (i-1) can be controlled with high accuracy, and the stands {(i-1) and {
The pressing position change time reduction device 4, 4 provided in the i be set to be the shortest time according to their ability, as much as possible the tension variation applied to the preceding material S _F or the following material S _B The off-gauge can be shortened. Further, the connection point P is set at each stand ♯ (i-
1), steep tension fluctuations that occur when passing through i are absorbed.

FIG. 4 is a partial schematic diagram showing another embodiment, in which the thickness of the material to be rolled at each stand # (i-1), #i is obtained by calculation. In the figure, parts corresponding to the parts shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The second control device 2 includes (i)
-1) The rolling loads P _i-1 and P _i of the rolling-down devices 4 and 4 are given from the rolling-down control devices 3 and 3 of the stand # (i-1) and the i-th stand #i. Further, the second control unit 2 both stand ♯ (i-1), the mill stiffness coefficient M _i-1, M _i of ♯i is given in advance.

The second control unit 2 calculates the rolling positions S _i−1 and S _i , the mill stiffness coefficients M _i−1 and M _i and the rolling loads P _i−1 and P _i calculated as described above in the following (3). ) or formula (4) is substituted into equation both stand ♯ (i-1), calculates the thickness h _i-1, h _i of the material to be rolled in #i, resulting thickness h _i-1 ,
by using the h _i, before as well (i-1) th stand ♯ (i-
The peripheral speed Vi _-1 of the work rolls 10 and 10 provided in 1) is calculated, and the calculated peripheral speed is provided to the (i-1) th stand # (i-1) peripheral speed control device 5, and the calculated peripheral speed is calculated. The rotational drive of the motor M is controlled so as to be Vi _-1 . _{h i-1 = S i-} 1 + P i-1 / M i-1 ... (3) h i = S i + P i / M i ... (4)

[0021] In the present embodiment, (3) and (4) are to calculate the thickness h _i-1, h _i of the rolled material in accordance with formula, but the present invention is not limited thereto According to the following equations (5) and (6), the thickness h _{i-1 of} the material to be rolled,
it is also possible to calculate the h _i.

[0022]

(Equation 1)

[0023]

Next, the results of a comparative test will be described. A rolling material comprising a preceding material and a succeeding material having different thicknesses is fed to a continuous rolling mill having first to seventh stands, respectively, and the method according to the present invention and disclosed in JP-A-6-15317 are disclosed. The rolling thickness change rolling was performed by applying the above method. In the method of the present invention, rolling was performed under the conditions shown in Table 1 below. Table 2 below shows the results of a comparison between the variation in tension of the material to be rolled and the off-gauge when rolling was performed by both methods.

[0024]

[Table 1]

[0025]

[Table 2]

As shown in Table 1, in the method of the present invention, the change time of the rolling position is determined according to the target thickness of the preceding material and the succeeding material at each stand and the capability of the rolling device provided at each stand. In spite of the shortest time, as is clear from Table 2, there was not much difference in tension fluctuation between the method of the present invention and the conventional method. On the other hand, as is clear from Table 2,
In the method of the present invention, the off-gauge is set to about 1 less than in the conventional method
/ 7.

[0027]

As described in detail above, in the method of the present invention, the present invention has excellent effects such as the ability to reduce the off-gauge while suppressing the fluctuation in tension.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a part of a continuous rolling mill used for carrying out the present invention and a control system thereof.

FIG. 2 is a flowchart showing a control procedure of a first control device shown in FIG.

FIG. 3 is a flowchart showing a control procedure of a second control device shown in FIG. 1;

FIG. 4 is a partial schematic diagram showing another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st control apparatus 2 2nd control apparatus 3 Depressing control apparatus 4 Depressing apparatus 5 Circumferential speed control device 7 Thickness gauge 8 Circumferential speedometer S _F Leading material S _B Trailing material P Connection point

Claims (1)

[Claims] 1. A material to be rolled is fed to a continuous rolling mill in which a plurality of stands having rolling rolls are arranged in tandem.
In the method of rolling while changing the target thickness of the material to be rolled between runs, based on the target thickness of the material to be rolled, the advance rate of the material to be rolled at each stand and the rolling position and the peripheral speed of the rolling roll are determined in advance. While calculating, the rolling position and the peripheral speed of the rolling roll of each stand are changed at a predetermined timing, the thickness of the material to be rolled at the outlet side of each of the two adjacent stands is obtained, and the downstream side The peripheral speed of the roll provided on the stand is detected, and the peripheral speed of the roll provided on the upstream stand is determined based on the detected peripheral speed, the obtained thicknesses and the advance rates at the two stands. A continuous rolling method comprising calculating and adjusting an adjustment amount.