JPH0333056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method and apparatus for cutting slabs in continuous casting equipment.

BACKGROUND ART In general, so-called gas cutting machines, hydraulic shears, and mechanical shears are used as cutting devices for continuous casting. In these cutting devices, a means for cutting the slab is attached so as to be movable in the direction in which the slab is pulled out, and when cutting the slab, the cutting means is clamped to the slab and runs in synchronization with the slab. During this running, the slab is cut. From the viewpoint of improving product yield, hydraulic shears and mechanical shears, which require almost no cutting allowance, are often used.

If such a cutting device is directly applied to horizontal continuous casting equipment, the following problems will occur. In horizontal continuous casting equipment, one cycle of continuous casting operation consists of (a) pulling and pushing back, (b) pulling and stopping, and (c) pulling, stopping, pushing back, and stopping in order to pull out the slab. An intermittent pull-out drive system is adopted. The drive device for the slab in horizontal continuous casting equipment performs one cycle of the above-mentioned continuous casting operation in a very short period of time, for example, 0.5 seconds, so a highly responsive servo drive system is used.

Therefore, if the above-mentioned cutting device is applied as is to such horizontal continuous casting equipment, when cutting the slab, the weight of the cutting means of the cutting device will be transferred to the drive system that pulls out the slab at a relatively high speed. This results in a load that disturbs the cycle of the continuous casting operation. In order to suppress this turbulence, excessive power is required to pull out the slab.

Another problem is that product yield is reduced. After the cutting command signal is given to the cutting device,
It takes a long time to actually start cutting, and it is important to check whether the slab is running at the maximum drawing speed within that time.
A large error occurs in the cutting length depending on whether it is stopped or pushed back.

Problems to be Solved by the Invention The purpose of the present invention is to provide continuous casting equipment that does not require an unnecessarily large capacity of the drive system for pulling out the slab, and that can accurately determine the cutting length of the slab. It is an object of the present invention to provide a method and apparatus for cutting slabs.

Means for Solving the Problems The present invention involves drawing out a slab obtained by cooling and solidifying molten metal from a tundish in a mold, and cutting the slab with a cutting means. The first operating mode of unplugging and the pause and/or
In a method for cutting slabs in continuous casting equipment that repeats a continuous casting operation cycle consisting of a second operation mode of pushing back or pushing back, the time when a command to cut the slab is issued is
Determine whether it is in (a) the previous period within the period of the first operating mode, (b) the remaining subsequent period within the period of the first operating mode, or (c) the period of the second operating mode. , (a1) If it is the previous period, (b1) If it is the after period, immediately move to the second operation mode, and after the end of the second operation mode, (c1) If it is the second operation mode, the second operation mode After the operation mode ends, the slab cutting means is moved together with the slab while the slab is being pulled out at a predetermined constant pulling speed that is lower than the withdrawal speed in the first operation mode and is relatively low enough not to interrupt the solidification cell. This is a method for cutting slabs in continuous casting equipment, characterized in that the slabs are cut by cutting the slabs.

Further, the present invention provides a method for pulling out a slab obtained by cooling and solidifying molten metal from a tundish in a mold by a pulling means, and cutting the slab by a cutting means, and the pulling means is a first step for pulling out the slab. one mode of operation and a second mode of operation for pausing and/or pushing back.
In a slab cutting device for continuous casting equipment that repeatedly performs a continuous casting operation cycle consisting of operation modes, the invention comprises: means for detecting the moving distance of the slab in the drawing direction; means for moving the cutting means together with the slab during cutting; means for generating a cutting command signal; and control means responsive to the output of the detection means,
The control means is configured such that the time point at which the disconnection command signal is generated is within (a) the previous period within the period of the first operating mode, (b) the remaining subsequent period within the period of the first mode, and (c) the period during which the cutting command signal is generated. (a1) Immediately if it is in the previous period; (b1) Immediately if it is in the later period, and then immediately after the end of the second operation mode. , (c1) when in the second operation mode, after the second operation mode is finished, while pulling out the slab by the pulling means at a drawing speed lower than the drawing speed in the first operation mode,
This is a slab cutting device for continuous casting equipment, characterized in that it includes a control means for moving the slab cutting means by a moving means to cut the slab.

Effect According to the present invention, when cutting, the slab is pulled out at a relatively low speed that does not interrupt the solidification cells, and the cutting blade is moved together with the slab to cut the slab. The load acting on the slab pulling drive system due to the weight of the slab can be reduced, and there is no need to unnecessarily increase the capacity of the slab pulling drive system.

During this cutting, the slab is pulled out at a predetermined low speed, and the slab is cut at this time, which reduces the variation in cut length of the slab and improves yield. be able to.

Furthermore, even when the slab is cut, the slab is pulled out at a relatively low, predetermined constant speed as mentioned above, and the slab does not stop during cutting, so there are no surface defects on the slab. This can be prevented from occurring.

Further, according to the present invention, when the cutting command signal is generated in the previous period within the period of the first operation mode, the drawing speed of the slab is relatively high, and therefore the slab is immediately cast. Perform the cutting operation with the piece at a low speed.

If the time point at which the cutting command signal is generated is the remaining period after the previous period within the period of the first operating mode, the second operating mode is entered immediately after the cutting command signal is generated. In this second operation mode, the slab is rested and/or pushed back, and the pushing back speed during pushing back is sufficiently smaller than the drawing speed, and the amount of pushing back is also small. Therefore, after the second operation mode ends, the slab can be accurately cut without making a large error in the cutting length of the slab.

When the cutting command signal is generated in the second operating mode, the second operating mode continues until the series of second operating modes is completed. After finishing the second mode of operation, cutting is performed at a lower drawing speed. In view of the fact that the amount of movement of the slab in the second operation mode is zero or very small,
It becomes possible to cut slabs at accurate cutting lengths.

Embodiment FIG. 1 is a sectional view of an embodiment of the present invention.
Molten steel 2, which is a molten metal, is stored in a tundish 1, and flows from a tundish nozzle 3 through a break ring 4 to a mold 5, where it is cooled and solidified, and a slab 7 is drawn out by a drawing means 6. It will be destroyed. The pulling means 6 has a plurality of drive rollers that come into contact with the outer peripheral surface of the slab 7, and the slab 7 is pinched and pulled out by the drive rollers.

The drawn slab 7 is guided by a roller table 8 and cut by a cutting means 9. This cutting means 9 includes a support member 11 that is swingably provided at a fixed position by a pin 10, a fixed blade 12 provided on this support member 11, and a support member 11 that is swingably provided at a fixed position.
The movable blade 13 is movable along a cutting stroke l1, a cutting hydraulic cylinder 14 drives the movable blade 13, and a movable hydraulic cylinder 15 swings the support member 11. The piston rod of the moving hydraulic cylinder 15 is connected to the support member 11 by a pin 16, and the moving hydraulic cylinder 15 is supported in a fixed position by a clevis pin 17. The pins 10, 16, 17 are perpendicular to the drawing direction 18 of the slab 7 and are horizontal.

Detection means 19 is provided to detect the moving distance of the slab 7 in the drawing direction 18. This detection means 19 may be realized by a configuration including, for example, a detection roller that rotates in contact with the slab 7 and a pulse counter that detects the number of rotations of the detection roller.

The cut end 7a of the slab 7 is detected by a detection means 20 disposed downstream of the cutting means 9 in the drawing direction 18.
can be detected by This detection means 20 is configured such that, for example, a light emitting element and a light receiving element are connected to a slab 7.
may have a configuration in which they are disposed opposite to each other on both sides of the travel route. The distance between the detection means 19 and 20 is known in advance, and therefore, after the detection means 20 detects the cut end 7a of the slab 7, the detection means 19 moves the slab 7 in the drawing direction 18. By detecting the distance, the length of the slab 7 can be determined. This detection means 19 has a configuration in which the count value is added when the slab 7 moves in the drawing direction 18, and the count value is subtracted when the slab 7 moves in the opposite direction.

FIG. 2 is a block diagram showing the electrical configuration. The detection means 19 and 20 provide detection outputs to a processing circuit 21 realized by a microcomputer or the like. The processing circuit 21 controls the motor of the extraction means 6, and also controls the cutting hydraulic cylinder 1.
4 and the moving hydraulic cylinder 15.

FIG. 3 is a diagram for explaining the moving operation of the slab 7. 3. 1 shows the velocity of the slab 7 over time, and FIG. 3 2 shows the integral value of the traveling speed of the slab 7 calculated by the processing circuit 21 in response to the output from the detection means 19. One cycle of continuous casting operation is the sum of the period W1 of the first operation mode and the period W2 of the second operation mode, and these periods W1,
The sum of W2 is, for example, 0.5 seconds, and one cycle of such continuous casting operation is repeated. During the period W1 of the first operation mode, the slab 7 is pulled out in the drawing direction 18, the drawing speed increases from time t1 to t2, the drawing speed is constant from time t2 to t3, and from time t3 to t4. Pulling speed decreases. During the period W1 of the first operation mode, the distance that the slab 7 is pulled out in the pulling direction is, for example, 5
~30mm.

In period W2 of the second operation mode, time t4
~t5, the slab 7 is at rest, and from time t5~
At t6, the slab 7 is pushed back at a relatively low speed in the opposite direction to the drawing direction 18, and from time t6 to t7, the slab 7 is at rest. The distance by which the slab 7 is pushed back between times t5 and t6 is, for example, 1 to 2 mm. By detecting the integrated value of the traveling speed of the slab 7 in FIG. 3, it is possible to know the progress of the operation during the period W1 of the first operation mode.

FIG. 4 is a flowchart for explaining the operation of the embodiment shown in FIGS. 1-3. Moving from step n1 to step n2, the detection means 19,
Based on the output from 20, the processing circuit 21 determines whether the slab 7 has moved in the drawing direction 18 by a predetermined cutting length 10 to be cut, and cuts the slab 7 by the predetermined cutting length l0. If it has not reached l0, the continuous casting operation is continued in step n3. When the slab 7 reaches the predetermined cutting length l0, the process moves to step n4 and the cutting operation shown in FIG. 5 is performed.

The cutting operation will be explained with reference to FIG. Moving from step m1 to step m2, it is determined whether the time rate of change of the integral value of the processing circuit 21 that integrates the output from the detection means 19 is positive, that is, whether there is an increment in the integral value. When it is determined that there is an increase in the integral value, the time when the cutting command signal is generated is during the period W1 of the first operation mode. In step m3, it is determined whether the integral value is greater than or equal to a predetermined value A (see FIG. 3, 2).
When the integral value is less than the value A, step
The first cutting pattern is executed at step m4, and when the integral value is greater than or equal to the predetermined value A, the second cutting pattern is executed at step m5.

In the above-mentioned FIG. 3, in the period W1 of the first operation mode, the previous period W, which is a period where the integral value is less than
1a, and a subsequent period W1b that is a period equal to or greater than the value A.
It can be divided into The time at which the integral value reaches this value A is indicated by the reference t2a.

The first cutting pattern executed in step m4 is as shown in FIG. 6, and at time t8 in the previous period W1a,
When the cutting command signal is given to the hydraulic cylinders 14, 15, the drawing speed of the drawing means 6 is immediately changed to a predetermined low speed V1, this speed V1 continues for a predetermined time W3, and then During the period W4, the drawing speed is reduced to zero, and then the second operation mode period W2 is entered. During a period W3 during which the slab 7 is at a low speed V1 and maintained at a constant value, the hydraulic cylinder 14 displaces and drives the movable blade 13 upward in FIG. Cut between. At this time, the hydraulic cylinder 15 swings the support member 11 so that the double blades 12 and 13 move in the drawing direction 18 at exactly the same speed as the slab 7 or at a speed slightly smaller than the slab 7. Displace. During this cutting, the cutting means 9 therefore do not place a load on the extraction means 6, or only place a very small load on them.

The second cutting pattern carried out in step m5 is shown in FIG. 62. When the time at which the cutting command signal is generated is time t9 in the later period W1b, the second operation mode is immediately entered from time t9 at which the cutting command signal in FIG. 62 is generated;
At time W2, the operations of pausing, pushing back, and pausing are performed. After that, from time t10 to time W5
The drawing means 6 draws out the slab 7, continues the drawing operation at a constant speed V1 during the subsequent time W3, and decreases the speed V1 during the time W4. Thereafter, in period W2, the second operation mode is performed, and then in period W1, the first operation mode is performed, and the cycle of continuous casting operation mode is repeated in the same manner. In the second operation mode W2 after time t9, the length of pushing back the slab 7 by the pulling means 6 is very small, and therefore the slab 7 is pushed back at a constant low speed V1 during the period W3.
While the slab 7 is being pulled out, the slab 7 is cut to an accurate cutting length by the cutting means 9.

In step m2 shown in FIG. 5 above,
If there is no increment in the integral value, the process moves to step m6 and a third cutting pattern is executed. This third cutting pattern is as shown in FIG. 6. The fact that there is no increment in the integral value means that
This means that the cutting command signal was generated during the period W2 of the second operation mode from time t4 to time t7. When the disconnection command signal is generated between times t4 and t7, the entire period W2 of this second operation mode is first completed, and then the period W2 from time t7 is
In step 5, the drawing speed is increased, and in period W3, the slab 7 is pulled out at a constant low speed V1, and then,
During period W4, the drawing speed is reduced to zero. After the subsequent time t12, the second operation mode and the first operation mode are alternately repeated to repeat the continuous casting operation cycle. The slab is cut during period W3.

The drawing speed V1 of the slab 7 by the pulling means 6 when cutting the slab 7 by the cutting means 9 is determined to be the speed at which solidification cells are continuously formed.

FIG. 7 is an enlarged sectional view of the vicinity of the break ring 4 and the mold 5. The molten steel 22 cools and solidifies in the vicinity of the break ring 4 and the mold 5 as shown by diagonal lines, and solidifies in the solidification cells 2.
3 is formed. In order to improve productivity, the drawing speed during period W1 of the first operation mode should be set to
It is desirable to make it as large as possible. In this way, when the drawing speed is increased during the period W1 of the first operation mode, when cutting the slab 7,
When the slab 7 is stopped, cut while it is stopped, and then drawn again at high speed,
This results in the coagulation cell being interrupted, as shown by phantom line 24. In order to solve this problem, the present invention pulls the slab 7 at a low speed V1 even when cutting the slab 7, in order to prevent the solidification cell 23 from being interrupted. As shown at 25, a coagulation cell 23 is formed and the coagulation cell is not interrupted. In this way, it is possible to produce high-quality slabs without surface defects.

FIG. 8 is a diagram showing the time course of the drawing speed of the slab 7 according to another embodiment of the present invention. Time t14~
In the period W7 of the first operation mode at t15,
The slab 7 is pulled out, and during the next period W8 of the second operation mode from time t15 to t16, the slab 7 remains stopped. These periods W7 and W8 constitute one cycle of the continuous casting operation, and such a cycle is repeatedly executed. 1st
During the operation mode period W7, from time t14 to t
In the previous period W7a of 14a, when the cutting command signal is generated at time t18 in FIG. 9, the speed is immediately set to a constant low speed V1, as shown in FIG. A cutting operation is performed during period W3.

Later period W7 of period W7 of the first operation mode
In the period from time t14a to t15, which is b,
When the cutting command signal is generated, as shown in FIG. 92, after time t19, the mode shifts to the second operation mode and pauses, and after the pause period W8 has elapsed, the drawing speed of the slab 7 is reduced from time t20. The speed is set to V1, and cutting is performed during this period W3. The cutting pattern shown in FIG. 92 is similar to the drawing pattern shown in FIG. 62.

Next, when the cutting command signal is generated within the period W8 of the second operation mode, the period W8 of the second operation mode first elapses as shown in FIG. The piece is set at a constant low speed V1, and cutting is performed during this constant low speed period W3. Such an operation is similar to the cutting pattern shown in FIG. 6 and FIG. 3 described above.

In another embodiment of the invention, in a first mode of operation, the slab is pulled out, and then in a second mode of operation, the slab is pushed back slightly, such operations forming a continuous casting operation cycle; Even when this cycle is repeated, the present invention can be implemented in the same way.

According to the experiments of the present inventor, in the embodiment shown in FIGS. 1 to 6, a constant high drawing speed during the period W1 of the first operation mode, that is, between times t2 and t3 in FIG. The speed at is
100 mm/sec, the push-back speed is 17 mm/sec from time t5 to t6 in FIG. 3, and time W1
is 220×10 ^-3 sec, and time W2 is 280×
10 ^-3 sec, and the speed V1 at the time of cutting is:
Defined as 20mm/sec. In FIG. 3 1, time t
1 to t2 is 40×10 ^-3 sec, and time t2 to t
3 is 140×10 ^-3 , and time t3 to t4 is 40×
10 ⁻³ sec, time t4 to t5 is 95×10 ⁻³ sec, time t5 to t6 is 90×10 ⁻³ sec, and time t6 to t7 is 95×10 ⁻³ sec. In this way, by setting the cutting speed V1 to a range of, for example, less than about 25% and 5% or more of the maximum drawing speed from time t2 to t3 in FIG. 3 in the period W1, and setting the low speed drawing period W3 to 4 seconds. As a result, it has become possible to cut high-quality slabs with minimum yield. The period W3 of the low speed V1 during cutting is set, for example, within 5 seconds.

The invention can be implemented not only in connection with horizontal continuous casting equipment, but also in connection with vertical continuous casting equipment, and in other applications as well.

Although the cutting means 9 was configured to cut the slab 7 using the hydraulic cylinders 14 and 15 in the above-described embodiment, cutting means having other configurations may be used in other embodiments of the present invention. For example, the blade may be driven to cut the slab by a crank mechanism rotated by a motor, and such blade may be moved along a rail parallel to the slab. It is also possible to provide the cutter on a trolley, run the trolley at substantially the same speed as the slab 7, and cut the slab while it is running.

Effects As described above, according to the present invention, the slab is cut while being pulled out at a constant low speed, so that an excessive load is not applied to the slab when cutting the slab. Therefore, disturbances in the pulling operation are suppressed, and there is no need to increase the capacity of the pulling means. By cutting the slab while it is being drawn out at a constant speed, variations in the cut length of the slab are reduced and the product yield is improved.

Furthermore, when the slab is cut, the slab is not stopped, but is pulled out at a constant low speed as described above, which prevents surface defects on the slab, resulting in high quality. can produce slabs.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the overall configuration of an embodiment of the present invention, Fig. 2 is a block diagram showing the electrical configuration of the embodiment shown in Fig. 1, and Fig. 3 explains the continuous casting operation. 4 and 5 are flowcharts for explaining the operation, FIG. 6 is a diagram for explaining the cutting operation, and FIG. 7 shows the vicinity of the break ring 4 and the mold 5. An enlarged sectional view, FIG. 8 is a diagram for explaining the continuous casting operation of another embodiment of the present invention, and FIG. 9 is a diagram for explaining the cutting operation in the embodiment shown in FIG. 8. . DESCRIPTION OF SYMBOLS 1... Tundish, 2... Molten steel, 4... Break ring, 5... Mold, 6... Drawing means, 7... Slab, 8... Roller table, 9...
Cutting means, 12... Fixed blade, 13... Moving blade, 1
4, 15... Hydraulic cylinder, 19, 20... Detection means, 21... Processing circuit, W1, W7... Period of first operation mode, W1a, W7a... Previous period, W
1b, W7b...later period, W2, W8...period of second operation mode.

Claims (1)

[Claims] 1. A slab obtained by cooling and solidifying molten metal from a tundish in a mold is pulled out, and the slab is cut by a cutting means, and the pulling operation is a first operation mode for pulling out the slab. In addition, in a method for cutting slabs in continuous casting equipment that repeatedly performs a continuous casting operation cycle consisting of a second operation mode of pausing and/or pushing back, the time when a command to cut the slab is issued is ( a)
(a1 ) When it is the previous period, immediately (b1) When it is the after period, immediately move to the second operation mode, and after the end of the second operation mode, (c1) When it is the second operation mode, the second operation mode After finishing, the slab cutting means is moved together with the slab while the slab is being pulled out at a predetermined constant pulling speed that is lower than the pulling speed in the first operating mode and is relatively low enough not to interrupt the solidification cell. , a method for cutting slabs in continuous casting equipment, characterized by cutting slabs. 2. A slab obtained by cooling and solidifying molten metal from a tundish in a mold is pulled out by a pulling means, and this slab is cut by a cutting means, and the pulling means operates in a first operation mode for pulling out the slab; In a slab cutting device for continuous casting equipment that repeatedly performs a continuous casting operation cycle consisting of a second operation mode of stopping and/or pushing back, means for detecting the moving distance of a slab in a drawing direction; and a cutting means. a means for moving the strand together with the slab during cutting; a means for generating a cutting command signal; and a control means responsive to the output of the detection means,
The control means is configured such that the time point at which the disconnection command signal is generated is within (a) a previous period within the period of the first operating mode, (b) a remaining subsequent period within the period of the first operating mode, and (c) Second
(a1) Immediately when in the previous period; (b1) Immediately when in the latter period; and when the second operation mode ends, ( c1) When in the second operation mode, after the end of the second operation mode, while drawing out the slab with the drawing means at a lower drawing speed than the drawing speed in the first operation mode,
1. A slab cutting device for continuous casting equipment, comprising: control means for moving the slab cutting means by a moving means to cut the slab.