JP3039330B2 - Slab cutting method in continuous casting machine - 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 cutting a slab in a continuous casting machine, and more particularly to a method for automatically cutting a slab by a cutting device running in synchronization with a slab manufactured in the continuous casting machine.

[0002]

2. Description of the Related Art In a continuous casting machine, slab cutting by a traveling cutting device is generally used so as not to impair its continuity. As is well known, the cutting device cuts the slab in the width direction with an attached transverse cutting torch while running in synchronization with the slab to be manufactured.

[0003] In the slab cutting of such a method, although the travel range of the cutting device is limited, the casting torch is usually used until the cutting device reaches the limit position of the travel range. One-sided cutting is completed. However, if the casting speed is accelerated during cutting, the traveling speed of the cutting device will increase with the acceleration, and depending on the acceleration, the cutting device may reach the limit position of the travelable range before the cutting is completed. There is.

[0004] In order to avoid such troubles, the traveling state and cutting state of the cutting device have been conventionally monitored by an operator. That is, while monitoring the casting speed, the operator monitors the progress of cutting in the cutting device on a television monitor, and determines whether or not the cutting device reaches the limit position of the travelable range before the cutting is completed. .
Then, when it is determined that the cutting device reaches the limit position before the cutting is completed, the operator reduces the casting speed. Each of the operations was subjective based on the intuition and experience of the operator.

[0005]

However, the conventional trouble avoidance measures by such an operator have the following problems.

The operator monitors various situations other than the disconnection. Therefore, the monitoring of the cutting device is neglected, and the reaching of the cutting device to the limit position may be overlooked.

[0007] Even if the cutting device is monitored more sufficiently, a determination error may occur because the criteria for determining whether the cutting device reaches the limit position are ambiguous. This determination mistake includes the case where the cutting device has not reached the limit position even though the cutting device has reached the limit position, and the case where the cutting device has determined arrival even though the cutting device has not reached the travel limit position. In the former case, the trouble of reaching the limit position occurs, and in the latter case, an unnecessary operation of lowering the casting speed is performed, so that the operation rate of the continuous casting machine is reduced.

[0008] Even if the judgment of reaching the limit position is correct, if the subsequent operation of setting the casting speed is erroneous, a trouble of reaching the limit position may occur, or the casting rate may be unnecessarily reduced to lower the operating rate. .

Further, in order to address these various problems,
The burden on the operator was very heavy.

SUMMARY OF THE INVENTION An object of the present invention is to reliably prevent a trouble that a cutting device reaches a limit position before cutting is completed,
An object of the present invention is to provide a method for cutting a slab that avoids an unnecessary decrease in the operation rate and also reduces the burden on the operator.

[0011]

SUMMARY OF THE INVENTION A slab cutting method according to the present invention is a slab cutting method for cutting a slab by a cutting device running in synchronization with a slab manufactured in a continuous casting machine. While cutting the slab, determine the distance traveled by the cutting device from the time required to complete the cutting and the casting speed to the completion of the cutting, and compare that distance with the remaining distance that the cutting device can travel to perform cutting. This is to quantitatively predict a trouble that the cutting device reaches the limit position of the travelable range before completion.

Preferably, the distance traveled by the cutting device until the completion of the cutting is determined once from the casting speed at or immediately after the start of the cutting of the slab and the time required for the completion of the cutting, and thereafter, the acceleration of the casting speed starts. If so, this distance is calculated again and compared with the remaining distance where the cutting device can travel.

When the distance traveled by the cutting device until the cutting is completed is obtained, the formula (1) is used if the casting speed is constant, and the formula (2) is used if the casting speed is accelerating or decelerating.
Accordingly, good determine the distance L ₁ of the cutting device until the completion of cutting is traveling. L ₁ = T ₁ × V _x (1) L ₁ = T ₁ × V _s − (V _s −V _x ) ² ÷ (2 × A) (2) T ₁ : Time required until completion of cutting V _x: casting speed V _s: target casting speed a when the casting speed is or decelerating during acceleration: the acceleration (if negative deceleration)

If the trouble is predicted, the time required for the cutting device to travel within the time required for the completion of the cutting, particularly, It is desirable to determine the casting speed that stops just before the limit position and to reduce the speed to that casting speed.

When the casting speed is reduced, it is preferable to use an acceleration B as shown in equation (3) in order to avoid a sudden speed change. _{B = (V s' -V x} ) ÷ T 1 ...... (3) where _{V s' = 2 × L 2} ÷ T 1 -V x V s': target casting speed V _x: casting speed T _1: cutting Time required for completion L ₂ : Remaining distance that the cutting device can travel

[0016]

During cutting of a slab, the distance traveled by the cutting device by the time the cutting is completed is compared with the remaining distance that the cutting device can travel by the time the cutting is completed, and it is detected that the former is greater than the latter. Thus, the trouble that the cutting device reaches the limit position of the travelable range before the cutting is completed is quantitatively and automatically predicted without depending on the operator.

When the trouble is predicted, it is possible to stop the cutting device within the travelable range, particularly immediately before the limit position, based on the time required until the cutting is completed and the remaining distance in which the cutting device can travel. By finding a necessary casting speed and reducing the casting speed to the required casting speed, the above-mentioned trouble is reliably prevented, and a reduction in the operation rate due to an excessively low casting speed is avoided.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a continuous casting machine having a traveling type cutting device, FIG. 2 is a schematic plan view for explaining the operation of the cutting device for traveling and cutting, and FIG. 3 is an example of a procedure for avoiding trouble. FIG. 4 is a chart showing the distance traveled by the cutting device until the cutting is completed.

In a continuous casting machine, a slab 2 is continuously drawn from a mold 1 by a pinch roll 3 as shown in FIG. A traveling cutting device 4 is provided downstream of the pinch roll 3. The cutting device 4 is shown in FIG.
As shown in the figure, the slab 2 is guided by rails 5 and 5 provided on both sides of the horizontal traveling path of the slab 2 to travel forward at the same speed as the slab 2 and travel forward. The slab 2 is cut during running by the traverse of the cutting torch 6 mounted on the side.

In FIG. 1, reference numeral 7 denotes a cutting control device for controlling the running of the cutting device 4 and movement of the cutting torch 6, etc., 8 denotes an arithmetic device, and 9 denotes a pinch roll control device.
Running position of the cutting device 4, L _x is the travel range length of the cutting device 4, V _x is the casting speed, y the movement position of the cutting torch 6, L _y torch movable range length, V _y torch Indicates the moving speed.

[0021] Then, the computing device 8 fetches the information about the casting speed V _x or the like from the pinch roll control device 9, the movement position y such travel position x and cutting torch 6 of the cutting device 4 from the cutting control device 7 Capture the information of
Using these pieces of information, arithmetic processing is performed for trouble prediction according to the procedure shown in FIG. Further, based on the trouble prediction information obtained by the arithmetic processing, a speed instruction for avoiding a trouble is given by the cutting device control 7 and the pinch roll control device 9.
Give to. Hereinafter, the procedure of FIG. 3 will be described in detail with reference to FIG.

The cutting device 4 starts moving forward from x = 0, and x =
It is assumed that the cutting of the slab 2 by the cutting torch 6 is started at the position 2. Then, in step S1, the traveling position x of the cutting start of the cutting device 4 (= 2) and from the driving range length L _x, the travelable remaining distance L ₂ of the cutting device 4 L ₂ =
Lx− _{x, and the process} proceeds to step S2.

[0023] determined in step 2, the movement position y and the movement distance L _y of cutting torch 6, the distance that the cutting torch 6 is moved to the cutting completed, that torch travel distance L ₃ by L ₃ = L _y -y , To step S3.

[0024] In step S3, a torch travel distance L ₃ obtained in step S2, and a torch travel speed V _y, the time required until completion of cutting, that is, by cutting the required time _{T 1 T 1 = L 3 ÷} V y Then, the process proceeds to step S4.

[0025] In step S4, the casting speed V _x at the start of cutting whether the vehicle is accelerating (or decelerating) is determined. That is, the acceleration is A, A> 0 is accelerated, and A <0
Is decelerated, it is determined whether or not A = 0.

[0026] In the case of A = 0 and proceeds to step S5, from the cutting duration T ₁ Metropolitan calculated in casting speed V _x and the step S3, the distance L ₁ of the cutting device 4 travels on to the cutting completion L ₁ = It is determined by T ₁ × V _x .

If A ≠ 0, the process proceeds to step S6.
This step, by using the casting speed V _x and the acceleration A and the target casting speed V _s, obtains a distance L ₁ of the cutting device 4 travels to the cutting completion by the following equation. The following equation corresponds to the area of the hatched portion in FIG. L ₁ = T ₁ × V _s − (V _s −V _x ) ² ÷ (2 × A)

[0028] When the distance L ₁ is obtained in step 5 and 6, the distance L ₁ at step 7, compared to the travelable remaining distance L ₂ of the cutting device 4 obtained in step 1.

When L ₁ ≦ L ₂ , when the cutting is completed, the cutting device 4 stops before the limit position of the travelable range.
Judge that there is no trouble. When L ₁ > L ₂ , the cutting device 4 reaches the limit position before the cutting is completed, so that it is determined that a trouble has occurred, and the process proceeds to step 8.

In step 8, the distance L ₁ traveled by the cutting device 4 until the cutting is completed is determined by the remaining travelable distance L of the cutting device 4.
The casting speed is ₂ or less, the cutting time required required until travelable remaining distance L ₂ and the cutting completed using a T ₁ L ₂ / T ₁
And the average casting speed within the time T ₁ is changed to this casting speed (L ₂ / T ₁ ).

When changing the casting speed, the acceleration B is set by the following equation in order to avoid a sudden change in speed. _{B = (V s' -V x} ) ÷ T 1

Here, V _s ′ is a target casting speed in changing the speed, and is set by the following equation. V _s ′ = 2 × L ₂ ÷ T ₁ −V _x

Although not shown in FIG. 3, while cutting the slab 2 by the cutting torch 6, it is monitored whether or not the casting speed is newly accelerated. is re foresee trouble again repeat steps S1,2,3,5 at that time, if the trouble is predicted, changing the casting speed V _x again in step S8.

Thus, the trouble that the cutting device reaches the limit position of the travelable range before the completion of the cutting is reliably predicted, and the trouble is prevented beforehand. Further, a decrease in the operation rate due to a decrease in casting speed is suppressed as much as possible.

Next, an example of predicting a trouble and an example of avoiding the trouble will be described by taking a slab cutting operation in an actual continuous casting machine as an example.

The travelable range length L _x of the cutting device is 6 m,
The movable range length L _y of the cutting torch to 0.6 m. That is, it is assumed that the cutting is started from the position of y = 0 m and the cutting is completed at y = 0.6 m. Further, 0.4 m / min cutting speed V _y set in the cutting controller, i.e. cutting torch
It shall move at 0.4 m / min.

Now, suppose that the cutting of the slab by the cutting torch is started when the traveling position x of the cutting device is x = 2 m. Casting speed V _x at this time is V _x = 3.0m / min,
The casting speed is accelerating and the acceleration A is A = 6 m / min.
^2, the target casting speed V _s is assumed to be V _s = 3.5 m / min, the information is sent to the arithmetic unit from the pinch roll control device.

Then, as a result of the calculation by the arithmetic unit, the cutting torch moving distance L ₃ until the cutting is completed is L ₃ = L _y -y =
0.6 m, and the time T ₁ required to complete the cutting is T ₁ =
L ₃ ÷ V _y = 0.6 ÷ 0.4 = 1.5 minutes. The cutting device running distance L ₁ to the completion of cutting is as follows. L ₁ = T ₁ × V _s − (V _s −V _x ) ² ÷ (2 × A) = 1.5 × 3.5- (3.5-3.0) ² ÷ (2 × 6) = 5 .23m

On the other hand, the remaining travelable distance L ₂ of the cutting device is L
₂ = Lx- _x = 6-2 = 4 m. L ₁ (5.23m)
> L ₂ (4m), so if the cutting is continued as it is,
It is predicted that the cutting device will reach the limit device of the travelable range by the time the cutting is completed.

If a trouble is foreseen in this way,
An arithmetic unit performs a setting calculation of the casting speed. That is, the target casting speed V _s ′ and the acceleration B are set as follows, and the pinch roll control device controls the speed of the pinch roll. V _s ' = 2 × L ₂ ÷ T ₁ -V _x = 2 × 4 ÷ 1.5-3.0 = 2.3 m / min B = (V _s -V _x ) ÷ T ₁ = (2.3- 3.0) ÷ 1.5 = -1.05m / minute ²

As a result, the cutting device travel distance L ₁ changes from 5.23 m to 3.68 m until the cutting is completed, as shown below.
Since L ₁ (3.68 m) <L ₂ (4 m), the trouble predicted above is avoided. L ₁ = T ₁ × V _s − (V _s −V _x ) ² ÷ (2 × B) = 1.5 × 2.3− (2.3−3.0) ² ÷ [2 × (−1. 05)] = 3.68m

[0042]

As described above, the method for cutting a slab in the continuous casting machine according to the present invention quantitatively analyzes the process of generating a trouble in which the cutting device reaches the limit position of the travelable range before the cutting is completed. Thus, the trouble can be accurately and automatically predicted without relying on the conventional subjective judgment by the operator. Therefore, not only the burden on the operator can be remarkably reduced, but also it is possible to reliably avoid troubles, and further, to avoid a situation where the casting speed is unnecessarily lowered, and to improve the moving rate of the continuous casting machine. be able to.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a continuous casting machine provided with a traveling cutting device.

FIG. 2 is a schematic plan view for explaining the operation of the cutting device for traveling and cutting.

FIG. 3 is a flowchart illustrating an example of a procedure for avoiding a trouble.

FIG. 4 is a chart showing a distance traveled by a cutting device until cutting is completed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Casting 3 Pinch roll 4 Cutting device 6 Cutting torch

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Tsujida 4-33, Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd. (72) Inventor Keinosuke Mori 4-chome, Kitahama, Chuo-ku, Osaka-shi, Osaka No. 5, No. 33, Sumitomo Metal Industries, Ltd. (56) References JP-A-59-150651 (JP, A) JP-A-60-3954 (JP, A) JP-A-6-34852 (JP, U) (58 ) Surveyed field (Int.Cl. ⁷ , DB name) B22D 11/16 B22D 11/20

Claims (2)

(57) [Claims] 1. A slab cutting method for automatically cutting a slab by a cutting device running in synchronization with a slab manufactured by a continuous casting machine, wherein the slab is cut by the cutting device and required until the cutting is completed. From the time and casting speed, the distance traveled by the cutting device until the cutting is completed is determined, and the distance is compared with the remaining distance that the cutting device can travel, so that the cutting device can travel before the cutting is completed. A method for cutting a slab in a continuous casting machine, which quantitatively predicts a trouble that reaches the temperature. 2. When the trouble is predicted, the cutting device stops within a travelable range within a time required until the cutting is completed, based on a time required until the cutting is completed and a remaining distance in which the cutting device can travel. 2. The method for cutting a slab in a continuous casting machine according to claim 1, wherein a casting speed to be obtained is determined, and the speed is reduced to the casting speed to avoid trouble.