KR20120073992A - Apparatus for controlling oscillation of edge dam of twin roll strip casting process and method therefor - Google Patents

Abstract

PURPOSE: An apparatus for controlling vibration form an edge dam in a twin-roll strip casting process is provided to effectively restrict the generation of edge skulls because the horizontal vibration of the edge dam is not converted into longitudinal vibration. CONSTITUTION: An apparatus for controlling vibration form an edge dam in a twin-roll strip casting process comprises horizontal and vertical vibration units. The horizontal vibration unit comprises a vibration unit, a servo valve, and a horizontal vibration controller. The vibration unit horizontally vibrates the refractory of the edge dam by horizontally vibrating a vibration plate(300) according to vibration waveforms. The servo valve outputs the vibration waveforms. The horizontal vibration controller applies the vibration waveforms to the servo valve, and controls the horizontal vibration of the vibration unit. The horizontal vibration controller comprises upper and lower loading cylinders the servo valve, and a wear controller. The upper and lower loading cylinders are placed in the rear upper and lower parts of the edge dam. The servo valve operates the upper and lower loading cylinders. The wear controller controls the servo valve.

Description

Edge Dam Vibration Control Apparatus and Control Method for Double Roll Sheet Metal Casting Process {APPARATUS FOR CONTROLLING OSCILLATION OF EDGE DAM OF TWIN ROLL STRIP CASTING PROCESS AND METHOD THEREFOR}

The present invention relates to an apparatus and a control method for controlling the vibration of the edge dam during sheet metal casting by a twin roll sheet metal casting process, and more particularly to the edge skull by horizontal vibration control of the edge dam during casting by a twin roll sheet metal casting apparatus An apparatus for controlling the edge dam vibration of a twin roll sheet metal casting process for suppressing the generation and growth of the same, and a control method thereof.

In general, a twin roll sheet casting process is a method of continuously supplying a molten steel to two rotating casting rolls and continuously manufacturing a sheet of about several millimeters directly from the molten steel.

As shown in FIG. 1, the twin roll type sheet casting device uniformly supplies molten steel between a pair of casting rolls 110 through a immersion nozzle 120 and rotates the pair of casting rolls 110 to cool. Solidified layers of molten steel formed on the surface of each casting roll 110 are being merged at the closest point to continuously cast a cast of constant thickness.

At this time, a pair of edge dams equipped with the refractory 150 is installed at both ends of the pair of casting rolls 110 to prevent the outflow of molten steel, and the movable surface of the refractory 150 of the edge dam preheated before casting The hot molten steel supplied between the pair of casting rolls 110 and the casting roll 110 which is water-cooled are contacted at the same time. Thus, the contact surface with the casting roll 110 of the refractory 150 surface of the edge dam is soon cooled and heat loss occurs around the molten steel is a condition that can be easily solidified.

Accordingly, as shown in FIG. 2, the molten steel 131 is solidified on the movable surface of the refractory 150 of the edge dam to generate an edge skull 132 and a wet surface skull 134, and the skull is an edge dam. Grow on the surface of the refractory 150. Among them, the edge skull 132 is repeatedly grown and dropped during casting, and is mixed with the edge portion of the cast steel 140 to reduce the quality of the cast steel, and when the skull is hardened, between the casting rolls 110 and the cast roll 110. Compression with the lower skull 133 may cause damage to the casting roll 110 or cause plate breakage.

In order to solve the above problems, a technique for preventing solidification of molten steel by injecting an inert gas into molten steel at the lower end of the edge dam, and a technique for physically removing the skull by vibrating the refractory of the edge dam with a constant amplitude, have been proposed.

Among these, the inert gas blowing technology is to install a metal tube at the lower end of the refractory of the edge dam and inject the inert gas into the molten steel at the lower end of the edge dam through the metal tube to prevent the solidification of the molten steel to reduce the skull, edge dam Although there is some effect in reducing the lower skull 133 of the edge dam, the surface skull 134 of the edge surface of the edge dam and the edge skull 132 generated at the contact surface of the casting roll of the edge dam movable surface are continuously generated. There is a growing problem.

In addition, the edge dam vibration technology is a technique for physically removing the skull by vibrating the edge dam refractory to a constant amplitude, as shown in Figure 3, when the vibration motor (not shown) rotates the eccentric shaft 330 Accordingly, the slide bushing 320 is in close contact with the cover 310 and the vibration is transmitted to the diaphragm 300, so that the lower portion of the slide bushing oscillates from side to side, such as a clockwork, as shown in FIG. 4. The refractory 150 of the edge dam vibrates to prevent the skull from being fused to the edge dam.

However, since the conventional technique has a fixed amplitude as a mechanical vibration method by the oscillation cam 302, in order to change the amplitude, the eccentric shaft 330 or the eccentric ring, etc., must be replaced before casting, and the amplitude may vary depending on the operator. There is a problem that the casting can be interrupted because the amplitude can not be adjusted even if the edge scull occurs during casting due to the difference in the casting, and because the refractory 150 of the edge dam is oscillated in the clockwise direction, the vibration at the top or bottom of the edge dam Is generated, the amplitude decreases toward the center of the edge dam, causing a dead zone (200), which is a non-vibration zone, to generate and grow a skull in this zone. have. However, in order to prevent dead zones from occurring, the amplitude may be large, but in this case, the edge dam may be damaged, causing the fragments to enter the cast steel.

In addition, during continuous casting for a long time, the edge skull 132 is fixed to the refractory 150 of the edge dam, or molten steel penetrates into the gap between the edge dam and the casting roll 110 and solidifies as shown in FIG. In the case of sticking, horizontal vibration of the edge dam is suppressed or horizontal vibration of the edge dam is shifted to the front and rear vibration, so that the formation and growth of the edge skull can not be effectively suppressed, and the sealing property of the edge dam is deteriorated and casting becomes unstable. there is a problem.

The present invention has been made to solve the above-described problem, by generating an edge skull by horizontally vibrating the edge dam, but by controlling the upper and lower wear rate of the edge dam refractory to prevent the horizontal vibration of the edge dam to transition back and forth And to provide an edge dam vibration control device and a control method thereof in a twin roll sheet metal casting process that can effectively suppress growth, improve the sealing property of the edge dam, and ensure casting stability to produce a thin plate of good quality. do.

In order to achieve the above object, the present invention is a device for controlling the vibration of the edge dam by using a horizontal vibrator and a vertical vibrator during thin plate casting by a twin-roll thin plate casting process, wherein the horizontal vibrator, the vibration plate according to the vibration waveform A vibrator configured to horizontally vibrate the refractory of the edge dam coupled to the diaphragm; A servovalve outputting a vibration waveform to the vibrator for the horizontal vibration; And a horizontal vibration control unit for applying a vibration waveform to the servovalve to control horizontal vibration of the vibration unit, wherein the vertical vibration unit includes upper and lower loading cylinders respectively installed at upper and lower portions of the rear of the edge dam, It provides a servo valve for operating the lower loading cylinder, and the edge dam vibration control device of a twin roll sheet metal casting process, characterized in that it comprises a wear control unit for controlling the servo valve.

In this case, the vibrating unit of the horizontal vibrating unit, the main body is built in the hydraulic line, the hydraulic cylinder fixedly coupled to the main body, the cylinder rod is installed to be movable to both sides of the hydraulic cylinder through the interior of the hydraulic cylinder, It is also characterized in that it is made of a support for connecting both ends of the cylinder rod and both sides of the diaphragm.

In addition, the horizontal vibration unit is characterized in that it further includes a vibration unit displacement measuring unit for transmitting the position information of the vibration unit is identified in real time to the horizontal vibration control unit.

In addition, the present invention is a method for controlling the vibration of the edge dam during thin plate casting by a twin-roll thin plate casting process, by controlling the vibration of the edge dam combined with the vibration plate horizontal vibration by vibrating the vibration plate according to the vibration waveform Edge vibration control of the twin roll type sheet casting process, characterized in that for controlling the upper wear rate of the refractory mounted on the edge dam is greater than the lower wear rate by increasing the pressing force of the upper loading cylinder installed on the upper portion of the edge dam rear. Provide a method.

Here, the thin plate is also characterized in that the martensitic stainless steel sheet containing 0.1% or more by weight carbon.

In addition, the refractory of the edge dam is characterized in that the upper wear rate is controlled to be 1.5 to 3 times the lower wear rate.

In addition, the control of the horizontal vibration of the edge dam is to reduce the edge skull by removing the vibration-free zone by horizontally vibrating the diaphragm according to the vibration waveform by using a servo valve and a cylinder that outputs the vibration waveform to the diaphragm. It also has its features.

In addition, the control of the horizontal vibration of the edge dam is characterized by maintaining a fundamental vibration waveform having an amplitude of 10 to 1,500 µm and a frequency of 0.1 to 20 Hz.

At this time, it is also characterized in that the horizontal vibration by adding a high frequency waveform having an amplitude of 5 ~ 50㎛ having a frequency of 50 ~ 100Hz to the basic vibration waveform.

According to the present invention, the edge dam is horizontally vibrated, but the upper and lower wear rates of the edge dam refractory are controlled differently, thereby preventing the horizontal vibration of the edge dam from shifting back and forth, thereby effectively suppressing the generation and growth of edge skulls, It is possible to produce a thin plate of good quality by improving the sealing property of the casting and ensuring the casting stability.

1 is a perspective view of a general twin roll sheet metal casting device.
2 is a schematic diagram showing a state of generation of edge skulls according to the prior art;
(A) is a front view of the conventional edge dam vibration apparatus, (b) is an enlarged view of a main part.
Figure 4 is a schematic diagram showing the vibration form of a conventional edge dam vibration device.
5 is a photograph of the casting material is generated edge pin.
Figure 6 is a schematic diagram showing the vibration form of the control device for the horizontal vibration of the edge dam according to an embodiment of the present invention.
7 is a view showing the configuration of a control device for the horizontal vibration of the edge dam according to an embodiment of the present invention, (a) is a side view, (b) is a rear view, (c) is a partial plan view.
8 is a schematic view of an edge dam of a twin roll sheet metal casting apparatus.
Figure 9 (a) is a graph showing the basic vibration waveform of the horizontal vibration of the edge dam, Figure 9 (b) is a graph showing the horizontal vibration waveform of adding the high frequency to the basic vibration waveform of the horizontal vibration of the edge dam.
Figure 10 (a) is a plan view showing the horizontal vibration of the edge dam in accordance with an embodiment of the present invention, Figure 10 (b) is a plan view showing a state in which the horizontal vibration is shifted back and forth by the disturbance.
11 is a graph showing the change of the front and rear vibration of the edge dam according to the change of the upper wear amount of the refractory of the edge dam.
12 (a) is a graph showing the mixing of the skull when applying the basic vibration waveform of the horizontal vibration of the edge dam when casting martensitic stainless steel sheet, Figure 12 (b) is a mixing of the skull when applying the high frequency waveform according to the present invention Graph showing aspect.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is described in detail with reference to drawings.

According to the present invention, the edge dam is horizontally vibrated, but the upper and lower wear rates of the edge dam refractory are controlled differently, that is, the upper wear rate of the edge dam refractory is greater than the lower wear rate, thereby preventing the horizontal vibration of the edge dam from shifting to the front and rear vibration. It is a technology that can produce thin plate of good quality by effectively suppressing the generation and growth of skull, improving the sealing property of edge dam, and securing casting stability.

Edge dam vibration control apparatus and control method of the twin-roll thin plate casting process according to the present invention, as shown in Figure 6 controls the vibration of the edge dam combined with the vibration plate horizontal vibration by vibrating the vibration plate according to the vibration waveform do.

In this case, the horizontal vibration control device of the edge dam is horizontal vibration of the diaphragm 10 in accordance with the vibration waveform as shown in Figure 7, horizontally horizontally refractory 150 of the edge dam coupled to the diaphragm 10 Vibration unit for vibrating is provided, and a servo valve for outputting the vibration waveform to the vibration unit, and a horizontal vibration control unit for applying a vibration waveform to the servo valve to control the horizontal vibration of the vibration unit.

In addition, the horizontal vibration control unit by using the servo valve and the hydraulic cylinder 20 to horizontally vibrate the diaphragm 10 in accordance with the vibration waveform to remove the non-vibration zone to reduce the edge skull.

Referring to FIG. 7 in detail, the vibration plate 410 is horizontal in accordance with the vibration waveform outputted from the servo valve of the diaphragm 10 coupled to the rear surface of the non-moving surface of the refractory 150 of the edge dam. By vibrating, the refractory 150 of the edge dam coupled to the diaphragm 410 vibrates horizontally to reduce the edge skull. In addition, the hydraulic body a (30) and the hydraulic line b (31) is installed on both sides of the main body 40, the hydraulic cylinder 20 is fixed to the main body 40, the main body 40 of the When oil flows into the hydraulic cylinder 20 through the hydraulic line a 30, the cylinder rod 25 is moved to the right by hydraulic pressure, and thus the diaphragm connected to the cylinder rod 25 and the support 42 ( 10) also moves to the right, the refractory 150 of the edge dam coupled to the diaphragm 10 is also moved to the right, and if controlled to the contrary is moved to the left, the refractory 150 of the edge dam is horizontal vibration It is.

Here, the horizontal vibration unit may further include a vibration unit displacement measuring unit for transmitting the position information of the vibration unit detected in real time to the horizontal vibration control unit.

Therefore, when using the horizontal vibration control method according to the present invention, since the dead zone which is not a vibration-free zone disappears horizontally to the left and right, the generation and growth of the edge skull is greatly reduced.

At this time, as shown in Fig. 9 (a), the horizontal vibration control of the edge dam is preferred to maintain a basic vibration waveform of amplitude 10 ~ 1500㎛, frequency 0.1 ~ 20Hz, the casting situation and the type of skull to be mixed It can be controlled to vary in the range of the amplitude and frequency according to.

If the amplitude is less than 10 μm or the frequency is less than 0.1 Hz, the resulting skull is not quickly removed and the casting quality is continuously mixed for a considerable period of time after the casting is started, and the quality of the casting is degraded. This is because if the frequency exceeds 20 Hz, the stability of the edge dam's refractory material will be affected or the life of the edge dam refractory will be reduced with abrasion.

Here, as shown in FIG. 9 (b), it is more preferable to add a high frequency waveform having an amplitude of 5 to 50 μm having a frequency of 50 to 100 Hz to the basic vibration waveform to horizontally vibrate. In addition, by improving the characteristics of the horizontal vibration of the edge dam to prevent the damage and abnormal wear of the refractory of the edge dam, and to suppress the generation and growth of edge skull generated in the refractory of the edge dam.

However, as shown in FIG. 10, when horizontal vibration of the edge dam is stopped or not normally performed due to disturbance during continuous casting, the edge skull grows and adheres to the refractory of the edge dam, or between the edge dam and the casting roll. Since molten steel penetrates into the gap and is fixed to the edge pin, the horizontal vibration of the edge dam is transferred back and forth by the pivot 44 of the edge dam. This prevents the formation and growth of edge skulls effectively. There is a problem that the sealing property of the resin is lowered.

In particular, when manufacturing martensitic stainless steel sheet containing 0.1 wt% or more of high carbon, the solidification ability of the edge portion is good, the edge skull and edge pins frequently occur, so the horizontal control of the edge dam is abnormally performed.

Therefore, in order to prevent this, the present invention increases the rolling force of the upper loading cylinder installed above the edge dam rear to control the upper wear rate of the refractory mounted on the edge dam is greater than the lower wear rate.

That is, as shown in Figure 8, the edge dam structure is formed to prevent the outflow of the molten steel on the drive side (DS) and the work side (WS), both sides of the pair of casting rolls, the DS edge dam ( 60 and the WS edge dam 61 are controlled by the upper shift cylinders 50, 51 for moving the edge dams upward and the upper and lower loading cylinders 70, 71, 72 for pressing the edge dams forward. In this case, in the present invention, by increasing the pressing force of the upper loading cylinder (70, 71) than that of the lower loading cylinder (72) by controlling the upper wear rate of the refractory of the edge dam is greater than the lower wear rate edge dam It is possible to minimize the occurrence of edge skull and edge pins that can act as a disturbance of horizontal vibration.

At this time, the upper and lower loading cylinders (70, 71, 72) is a wear control for the refractory 150 of the edge dam through the servo valve received a control command by the wear control unit.

Here, the refractory of the edge dam is preferably controlled so that the upper wear rate is 1.5 to 3 times the lower wear rate, when the upper wear rate is less than 1.5 times the lower wear rate, the generation of edge skull acting as disturbance of the edge dam horizontal vibration and There is a problem that the growth may increase or the sealing of the edge dam may be poor, and if the upper wear rate exceeds three times the lower wear rate, the edge dam is accompanied by abnormal wear of the refractory of the edge dam due to the excessive difference of upper and lower wear rate. This is because there is a problem that the life of the refractory can be reduced.

As such, by increasing the pressing force of the upper loading cylinder, the upper wear rate of the refractory of the edge dam is controlled to be 1.5 to 3 times larger than the lower wear rate, thereby reducing disturbance to horizontal vibration of the edge dam. Transition to vibration can be reduced to minimize the generation and growth of edge sculls.

[Example 1]

When the molten steel including C: 0.5%, Cr: 13.5% and Ni: 0.6% by weight is injected into a twin roll type sheet casting machine, the diaphragm is formed by the horizontal vibration control device shown in FIG. 10) Add a high frequency waveform with an amplitude of 5 to 50 µm with a frequency of 50 to 100 Hz to the basic vibration waveform with an amplitude of 10 to 1,500 µm and a frequency of 0.1 to 20 Hz from the servovalve to control the horizontal vibration of the edge dams, and When the edge skull starts to be generated during the process, the reduction force of the upper loading cylinders 70 and 71 of the edge dam increases from 1.0 times to 3.5 times the reduction force of the lower loading cylinder 72, and the upper wear rate of the refractory of the edge dam is increased. The front and rear vibration amount of the edge dam was measured while controlling the lower wear rate, and the results are shown in the graphs of Table 1 and FIG.

[Table 1]

As shown in Table 1 and Figure 11, in the case of controlling the edge dam so that the upper wear rate is 1.5 to 3 times the lower wear rate in Inventive Examples 1 to 4, it is confirmed that the front and rear vibration amount of the edge dam is reduced than Comparative Example 1 As the magnification increases, the amount of front and rear vibration of the edge dam decreases, and the suppression effect of the edge skull is increased. This reduction of the front and rear vibration amount of the edge dam to remove the disturbance to the horizontal vibration of the edge dam to suppress the generation and growth of the edge skull, reducing the gap between the casting roll and the edge dam of Figure 5 due to the penetration of molten steel The formation of edge pins can be prevented to produce thin sheets having good edge quality.

However, in the case of Comparative Example 2, the upper wear rate was 3.5 times the lower wear rate, so the front and rear vibration amount of the edge dam was reduced to ± 40㎛, but due to the excessive difference between the upper and lower wear rate, abnormal wear of the refractory of the edge dam was prevented. Due to the accompanying problems, it was confirmed that the conditions are difficult to operate due to the reduced life and cost of the refractory of the edge dam.

[Example 2]

In addition, when a molten steel having the same composition as in Example 1 is injected into a twin roll type sheet casting machine to cast martensitic stainless steel, when edge scull is generated, the change in the reduction force (RSF) of the casting roll is increased. As shown in 12 (b), the fundamental vibration waveform shown in FIG. 12 (a) is further applied to the fundamental vibration waveform of the edge dam horizontal vibration by additionally applying a high frequency waveform having an amplitude of 5 to 50 µm having a frequency of 50 to 100 Hz. The results of this study were compared with the applied method of the edge dam horizontal vibration control method and the skull mixing condition.

As a result, as shown in Figs. 12 (a) and 12 (b), when the high frequency waveform is additionally applied, the mixing mode of the skull is reduced compared to the application of only the basic vibration waveform, so that the change in the reduction force (RSF) of the casting roll is reduced. It can be seen that the degradation is below a certain level.

As a result, the edge dam vibration control method of the twin-roll thin sheet casting apparatus according to the present invention is applied to the horizontal vibration by applying the high frequency waveform to the basic vibration waveform edge edge by controlling the upper and lower wear rate of the refractory of the edge dam differently It is possible to produce martensitic stainless steel sheet having good quality by effectively suppressing the production and growth, improving the sealing property of the edge dam, and ensuring the casting stability.

110. Casting Roll 120. Nozzle
130. Molten steel pool 131. Molten steel
132. Edge Skull 133. Lower Skull
134.Sweet noodles skull 140.Cast
150. Edge dam refractory 200. Dead zone
300. Diaphragm 301. Central bearing
302. Oscillation Cam 310. Cover
320. Slide bushing 330. Eccentric shaft
10. Diaphragm 20. Hydraulic cylinder
25. Cylinder rod 30. Hydraulic line a
31. Hydraulic line b 40. Main body
41. Vibration Displacement Meter 42. Support
43. Bolt assembly 44. Pivot
50. DS Upper Shift Cylinder & Position Sensor
51. WS Upper Shift Cylinder & Position Sensor
60.DS edge dam 61.WS edge dam
70. Upper loading cylinder (FR) 71. Upper loading cylinder (MR)
72. Lower loading cylinder

Claims (9)

In the device for controlling the vibration of the edge dam by using a horizontal vibrating portion and a vertical vibrating portion during thin plate casting by a twin roll type sheet casting process,
The horizontal vibrator may include: a vibrator configured to horizontally vibrate the diaphragm according to the vibration waveform to horizontally vibrate the refractory of the edge dam coupled to the diaphragm; A servovalve outputting a vibration waveform to the vibrator for the horizontal vibration; And a horizontal vibration control unit for applying a vibration waveform to the servovalve to control horizontal vibration of the vibration unit.
The vertical vibration unit includes an upper and lower loading cylinders installed at upper and lower portions of the rear of the edge dam, a servo valve for operating the upper and lower loading cylinders, and a wear control unit for controlling the servovalve. Edge dam vibration control device of twin roll sheet metal casting process. The method of claim 1,
The vibrating unit of the horizontal vibrating unit includes a main body having a hydraulic line installed therein, a hydraulic cylinder fixedly coupled to the main body, a cylinder rod installed to move to both sides of the hydraulic cylinder through the inside of the hydraulic cylinder, and the cylinder rod. Edge dam vibration control device of a twin-roll thin plate casting process, characterized in that made of a support for connecting both ends of the diaphragm and both sides of the support plate. The method of claim 1,
The horizontal vibration unit edge dam vibration control device of a twin roll thin plate casting process, characterized in that it further comprises a vibration unit displacement measuring unit for transmitting the position information of the vibration unit identified in real time to the horizontal vibration control unit. In the method of controlling the vibration of the edge dam during thin plate casting by a twin roll type sheet casting process,
By vibrating the vibration plate horizontally in accordance with the vibration waveform, the refractory of the edge dam coupled with the vibration plate is controlled to be horizontal vibration,
Edge dam vibration control method of the twin-roll thin sheet casting process, characterized in that to control the upper wear rate of the refractory mounted to the edge dam is greater than the lower wear rate by increasing the pressing force of the upper loading cylinder installed on the upper side of the edge dam . The method of claim 4, wherein
The thin plate is a martensitic stainless steel sheet containing a carbon by 0.1% or more by weight percent edge dam vibration control method of the thin roll casting process. The method of claim 4, wherein
Refractory of the edge dam is the edge dam vibration control method of the twin-roll thin plate casting process, characterized in that the upper wear rate is controlled to be 1.5 to 3 times the lower wear rate. The method of claim 4, wherein
In the horizontal vibration control of the edge dam, the vibration plate is horizontally vibrated according to the vibration waveform by using a servovalve and a cylinder which output the vibration waveform to the diaphragm, thereby eliminating an area where no vibration occurs, thereby reducing edge scull. Edge Dam Vibration Control Method of Twin Roll Sheet Casting Process. 8. The method according to any one of claims 4 to 7,
Control of the horizontal vibration of the edge dam, the edge dam vibration control method of the twin-roll thin sheet casting process, characterized in that to maintain the basic vibration waveform of amplitude 10 ~ 1,500㎛, frequency 0.1 ~ 20Hz. The method of claim 8,
Edge vibration vibration control method of the twin roll type sheet casting process characterized in that the horizontal vibration by adding a high frequency waveform having an amplitude of 5 ~ 50㎛ having a frequency of 50 ~ 100Hz to the basic vibration waveform.

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