JPS5823803B2 - Deceleration control method for reversible rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration control method for a reversible rolling mill, and more particularly to a method for calculating a take-off speed and a method for determining a deceleration start point.

Figure 1 shows an outline of a reversible rolling mill.
2 is a deceleration hot mass detector, 13 is a load cell, 14 is a main roll, 15 is an inlet roller table, and 15' is an outlet roller table.

16 is the rolled material, 11 is the rear end stopping distance of the rolled material 16 when it is sent in the forward direction and rolled, and this is the tip position of the rolled material 16 in the next pass when it is sent back and rolled in the reverse direction. It is also the distance from the main roll 14.

In such a structure, the speed pattern during reversible rolling is shown as shown in FIG. 2, and the speeds are divided into the following three types.

(A) Biting speed 1 (B) Rolling speed 2 (C) Biting speed 3
This is done by the rotation of the exit roller table 15', and each moves synchronously.

Therefore, at the speeds of (a), (b), and (c) above, the main roll 1
4. The entry roller table 15 and the exit roller table 15' are each rotating.

That is, in case (a), the main roll 14, the inlet roller table 15, and the outlet roller table 15' all have a biting speed of 1.

This allows slip-free rolling between the rolled material 16 and the main roll 14/roller tables 15, 15'.

Furthermore, the speed of the input roller table 15 is slower than that of the output roller table 15' by the amount by which the rolled material 16 is rolled down.

Usually, the biting speed 1 and the rolling speed 2 are determined in advance for each pass according to a rolling schedule.

The main roll 14 and roller table 15 are started at a biting speed of 1.

That is, the rolled material 16 is started at the time point shown in FIG. 2 and accelerated at a biting speed of 1.

The load cell 1 controls the biting of the rolled material 16 into the main roll 14.
3, start accelerating the roller table 15 and main roll 14 to rolling speed 2 from point 5;
Acceleration is completed at 5'.

Then, when the rear end of the rolled material 16 reaches a certain point, the main roll 14 and the roller table 15 are separated from each other, and deceleration is started at a speed of 3 and 6, but the separation speed 3 is calculated by a computer (not shown). be.

When the load cell 13 detects the release of the rear end of the rolled material 16 from the main roll 14, the roller table 15
At time 7, a stop command is issued, and the main roll 14 is set to the preparation speed for the next pass.

Next, the rear end of the rolled material 16 becomes the tip, and is fed backward from the rear end stop position to be bitten by the main roll 14, and the next pass of rolling is controlled in the same manner as described above.

Conventionally, in such reversible rolling control, the distance between the main roll 14 and the rear end stop position of the rolled material 16 after the rolled material 16 is separated is always kept constant in both directions of forward and reverse rolling.

This constant distance is sufficient to accelerate the biting speed 1 of the next pass to that speed until it bites into the main roll 14, and is also sufficient for predetermined work to be done between passes, such as material It is also a sufficient distance to carry out operations such as tilting to rotate the rolling material by 900 degrees or 180 degrees, a descaler to remove oxides on the surface of the rolled material, and changing the pitcher of the reduction roll of the rolled material.

Since the distance of bite and release determined in this way is constant, and the deceleration rate of the table after bite and release is also constant,
The release speed 3 is also constant.

That is, if the bite-off speed is vK, the table deceleration rate is α1, and the bite-off distance is 11, then the following can be obtained.

Note that the table deceleration rate here means that the material and the roller table can be decelerated without slipping, and the above-mentioned separation distance 10 is the turning distance in the next pass.

This conventional rolling method will be explained with reference to FIG. 5-5') The acceleration is interrupted and the rolling is performed at the speed vR1.

Next, the starting point of deceleration must be determined so that the rolled material 16 is separated from the main roll 14 just when the deceleration from vRl to vK is completed.

The deceleration start point is determined by applying a deceleration timer T1 from the time when the rear end of the rolled material 16 passes through the deceleration hot mass detector 11.

In other words, from now on Therefore, T1 can be found by calculating equation (1).

However, 12 is the distance between the deceleration hot mass detector 11 and the main roll 14, and α2 is the deceleration rate of the main roll 14.

In this way, the deceleration start point 6 is determined by the deceleration timer T□.

Further, the rolling in the reverse direction is similarly controlled using the hot mass detector 12.

However, in this conventional method, the separation distance 11 after the rolling material 16 is removed is set as a distance sufficient to perform the predetermined work regardless of the biting speed in the next pass, as described above. It was kept constant.

For this reason, the separation distance may become larger than necessary, and the rolling time becomes longer.

Also, if the rolled material 16 passes through the deceleration hot mass detector 11 during acceleration (this tends to happen mainly when the rolled material 16 is short)
Since the acceleration is interrupted, the rolling speed cannot be increased completely and the rolling time becomes longer, which impairs productivity.

Furthermore, since the deceleration hot mass detector 11 is installed at a position where it can sufficiently decelerate even when the rolling speed reaches the highest possible value, the value 12 in FIG. 3 is quite large, and therefore the rolling speed is When the value is low, the deceleration timer T□ takes a large value, and the accuracy of the deceleration starting point 6 deteriorates.

The present invention has been made in view of the above reasons, and can compensate for the drawbacks of the conventional methods described above and minimize the rolling time.
The object of the present invention is to provide a method for controlling the deceleration of a reversible rolling mill with improved productivity.

As mentioned above, the point of the invention is to minimize rolling time.

In order to reduce this rolling time as much as possible, the present invention focuses on the following three points.

(b) Optimization of bite distance...If it is too fast, it will take time to bite the next pass.

(b) Obtain the maximum value of the bite-off speed that can stop at the distance determined in (a) above.

(c) Calculate the last possible timing at which the chewing speed can be reduced to the one determined in (b) above.

...The slower the deceleration timing, the shorter the rolling time.

That is, by optimizing the separation distance after the rolling pass and minimizing the total time during which the rolls do not chew the material during reversible rolling, the slowest deceleration point that can satisfy the above separation distance is determined.

If the deceleration during rolling is performed early, the separation distance can be shortened, but the rolling time becomes longer.

On the other hand, if the deceleration point is delayed too much, the rolling time will be shortened, but the separation distance will become long, and it will take time to bite the next bus.

In other words, the rolling time is not shortened. From the above, in the present invention, in a reversible rolling mill, the disengagement distance after the current pass is determined from the rolling method of the next pass, and the greater of the disengagement distance determined from the bite speed of the next pass is used.

From this, the setting target for the separation speed of the current path is calculated, the timer value from the hot mass detector at the fixed position to the deceleration start position is calculated, and deceleration is performed using this timer value. .

The present invention will be described in detail below with reference to an embodiment shown in the drawings.

FIG. 4 is a configuration diagram of an apparatus for carrying out the method of the present invention, in which a plurality of rollers (in this case, two
The deceleration thermal mass detectors 22 and 23 are also provided on the exit roller table 24, and similar deceleration thermal mass detectors 25 and 26 are provided on the exit roller table 24 to detect the release of the material from the main roll 34. It has a load cell 27 and a rotation speed measuring device 28 for detecting the rotation speed of the main roll 340.

Furthermore, the electronic computer 29 has thermal mass detectors 22, 23° 25
．． 26, an analog input device 29a that inputs the values from the rotational speed measuring device 28, and voltages prepared for supplying power to the various drive motors 30, 31, and 32. Supply control device 3
There are 3.

This voltage supply control device 33 is an analog output control device! 29
Receives a speed reference command from c, drive motors 30, 3L3
2 to rotate at a speed commensurate with the speed reference command.

The method of this invention will be explained below.

(1) Determining the separation distance of the rolled material Minimizing the distance 11 in Figure 3 of the force cylinder is the first step in shortening the rolling time.

This 11 is determined by the biting speed of the next pass and the content of predetermined work to be performed between passes.

As mentioned above, this was conventionally set as a constant value, but in the present invention, 11 is determined by the following method. For example, when only the roll reduction device of the rolling mill is changed to the value for the next pass, A is the case where the material is tilted (the material is tilted at 90° or 18°).
0° rotation) is B, and C is the case where a rolling descaler (high-pressure water or steam spray applied to remove oxides on the surface of the rolled material) is used.The rolling mill and its accompanying equipment are passed. These triads A, B, C, etc., which mean to move each time, can be combined to perform various complex tasks.

The VNE of the above equation (2) is determined by the biting speed (rolling schedule) of the right roller table 24, which is the input side of the next pass.

) α1 is the acceleration rate of the roller table 21 or 24.

Therefore, lIA is the distance required to bite the next pass,
It is obtained by calculating equation (2).

Further, llA""'lIZ is a constant that can be predetermined as a separation distance required in a predetermined operation between rolling passes.

This is stored in the electronic computer μs.

The existence of these predetermined operations to be performed between the current pass and the next pass,
None and their contents are specified in the rolling schedule.

The electronic computer λ' obtains the corresponding separation distance for the predetermined work specified in this rolling schedule.

If there are multiple specified tasks, the maximum separation distance among them is selected.

This value is compared with the AIA obtained by calculating the above equation (2), and the larger one is determined to be the current path separation distance of 11.

The distance thus determined is the minimum value for that path.

(2) How to determine the take-off speed of rolled material Once the take-off distance is determined, take-off speed vK is calculated using the following formula.
is required.

That is, when the above equation is transformed by -, it becomes a quadratic equation for vK.

From this, the solution (3) that is actually used can be obtained.
Ru.

However, α1 is the table deceleration rate (constant), and tdl is the response time (constant) of the electronic computer 29 and the machine. It is desirable that the deceleration timer T1 has a small value.

The reason for this is that the longer the time, the less distance accuracy can be obtained due to changes in the speed of the material and detection errors.

Therefore, in this invention, a plurality of deceleration thermal mass detectors 2
2, 23, 25, and 26, and it is determined which of the deceleration thermal mass detectors 22, 23, and 25, 26 should be used to apply the deceleration timer T1.

Assume now that rolling is being carried out in the normal rotation direction in FIG.

If the deceleration timer is set by the deceleration hot mass detector n and deceleration is started after the timer amplifier (timer time count ends), the deceleration is completed by the time the rolling mill is separated from the main roll 34. Even if the deceleration timer is calculated and applied by the deceleration thermal mass detector 22, the deceleration should be the same as when the deceleration thermal mass detector 23 sets the timer.

However, since the timer set by the deceleration heat mass detector 22 is longer than the timer set by the deceleration heat mass detector 23, there is a correspondingly higher possibility of disturbance occurring as described above, and the accuracy deteriorates.

In this way, start the deceleration timer as much as possible from main roll 3.
It is desirable to start with a deceleration thermal mass detector close to 4.

Therefore, the maximum rolling speed vR2 at which deceleration is possible must be determined using the deceleration hot mass detector 23.

Fig. 5 is a diagram for explaining the maximum rolling speed vR2 at which this deceleration is possible, where the deceleration rate of the mill is α2 (constant), the response time (constant) of the computer 29 and the machine is td2, If the distance (constant) between the detector 23 and the load cell 27 is 13, and the draft compensation rate (defined by the rolling schedule) is ρ, the maximum rolling speed vR2 can be found from the following equation.

That is, since the speed of the inlet roller table 21 is slower than the speed of the outlet roller table 24 by the amount by which the material is rolled down, taking this into consideration, the following equation is obtained.

If we transform this for vR2, we can solve for the quadratic equation R2 of vR2, and from this we can obtain the solution (4) that is actually used.
Ru.

When the tail end of the rolled material passes through the deceleration hot mass detector 22, if the rolling speed of the current pass determined by the rolling schedule is vR, then when VR2≦vR holds, the deceleration timer T1 detects the deceleration heat. Even if the lump detector 23 tries to start it, it will be too late, so the deceleration hot lump detector 22
I have to start it up more.

In this way, the electronic computer i can determine which deceleration thermal mass detector is to be used in the current path.
This allows relatively high rolling speeds to be scheduled.

In addition, when the rolled material is relatively short, it is not necessary to maintain the current rolling speed when the rolled material passes through the first deceleration hot mass detector 22 during acceleration (see equation (6)). The invention becomes valid.

(4) Calculation of deceleration timer T1 The length of deceleration timer T1, which is activated by the signal of the deceleration thermal mass detector used, is determined by the following calculation.

When the trailing end of the rolled material passes through the deceleration hot mass detector, the electronic computer 29 reads the speed ■R1 of the main roll 34, obtains the rolling speed setting value vR for the current pass from the rolling schedule, and compares the two.

When VRI"VR (acceleration completed) When VR1 and VR≦vR2 (accelerating) (However, the timer from the deceleration thermal mass detector 22 and 26) However, 14 indicates the center of the deceleration thermal mass detector and mill to be used. It is the distance to the line.

The value of this calculation result is the length T1 of the timer activated by the signal from the deceleration thermal mass detector.

As described in (1) to (4) above, the minimum separation distance.

According to the deceleration control method in a reversible rolling mill based on the determination of the optimal deceleration hot mass detector to be used, productivity is improved compared to the conventional method.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the outline of a reversible rolling mill, Fig. 2 is a diagram of the speed change of the rolling mill in Fig. 1, and Fig. 3 is a diagram for explaining the deceleration control method of a conventional reversible rolling mill. , FIG. 4 is a block diagram of an apparatus for carrying out the method of this invention, and FIG. 5 is a diagram for explaining the method of this invention. 1... Biting speed, 2... Rolling speed, 3... Breaking off speed, 4... Rolling material start, 5... Acceleration start, 5 (... Acceleration completed, 6... Deceleration started, 7... Rolled material stopped, 21, 24... Roller table, n. 23. 25, 26... thermal mass detector for deceleration, 13
゜27...Load cell, 28...Rotation speed detector, 29...Electronic computer.

Claims (1)

[Claims] 1. A pair of roller tables are provided on the inlet and outlet sides of the main roll, a material to be rolled is placed on the roller table, and the material to be rolled is transferred and rolled by driving the main roll and the roller table. a driving device, a plurality of hot lump detectors arranged along the inlet and outlet sides of the main roll and the roller table to detect and output the position of the rolled material, and a hot mass detector provided on the main roll to separate the rolled material. It is equipped with a load cell that detects and outputs the rotational speed of the main roll, and a rotational speed interceptor that detects and outputs the rotational speed of the main roll.
In a reversible rolling mill that continues rolling passes from one direction to the other, (a) the next pass is determined by the speed of the entry roller table synchronized with the biting speed of the main roll of the next pass and the acceleration rate of the table; (b) calculating the separation speed of the rolled material from the calculated separation distance and the response time of a machine such as a computer; (c) The deceleration from each of the hot mass detectors is calculated based on the distance between the plurality of hot mass detectors and the load cell, the deceleration rate of the rolling mill, the response time of machines such as computers, and the draft compensation rate determined by the rolling schedule. Each possible maximum rolling speed vR2
calculating the rolling speed setting value vR of the current pass and selecting the hot lump detector closest to the main roll by comparing it with the rolling speed setting value vR1 of the current pass;
Compare R2 and the speed VRI of the main roll when the rear end of the rolled material passes through the hot lump detector, and when VRI "VR...", acceleration is complete vR1 - vR
A reversible method comprising: determining that acceleration is in progress when ≦vR2... and calculating the time required to reach a deceleration point at which deceleration is applied correspondingly to each case, and starting deceleration from the deceleration point. Rolling mill deceleration control method.