JPS61169156A - Method for dischargind molten metal from vessel for molten metal containing means for preventing clogging of sliding nozzle - Google Patents

Abstract

PURPOSE:To prevent the clogging of a sliding nozzle and to improve the quality of an ingot by incorporating an oscillation plate having a nozzle hole to a sliding plate of the sliding nozzle and discharging a molten metal while applying a specific frequency or above of fine oscillation thereto. CONSTITUTION:The sliding nozzle 10 superposed with an upper plate 5, the sliding plate 4 and a lower plate 6 is provided to the lower part of a vessel nozzle 9 and further the fine oscillation plate 3 is incorporated into the central part of the plate 4. The fine oscillation of >=1Hz frequency is applied to the plate 3 by driving an oscillating device 1 in the stage of sliding the plate 4 by a driving device 2 and pouring a molten metal through nozzle holes 5a, 6a and an immersion nozzle 7. the prevention of the nozzle clogging is thus made possible and the blowholes of ingot due to disturbance are eliminated.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for discharging molten metal from a molten metal container through a sliding nozzle.

(Prior Art) Conventionally, as a nozzle for discharging molten metal in a molten metal container, a fixed upper plate brick having a nozzle hole is used, and the nozzle hole is opened and closed as necessary by sliding on the upper plate brick. A sliding nozzle is used that is composed of a sliding plate brick that is squeezed, and a lower plate brick that is fixed and communicates with the nozzle hole of the sliding plate brick. When molten metal is flowed out using this sliding nozzle method, when the sliding plate brick is moved to close the nozzle hole, the molten metal remaining in the nozzle hole solidifies until the next molten metal flows out. may not be carried out smoothly. Therefore, in the past, even when the sliding plate brick was closed, the molten metal did not solidify inside the nozzle hole, but always flowed.
Several methods of maintaining the molten state have been proposed.

That is, as seen in Japanese Patent Application Laid-Open No. 51-122626, a porous nozzle brick is fitted into the lower part of the nozzle hole of the upper plate brick, an annular gap is formed around the outer circumference, and an inert gas introduction pipe is inserted into the gap. When inert gas is supplied from the inlet pipe, the inert gas is blown into the nozzle hole from the porous nozzle brick through the annular gap, moving the sliding plate and closing the nozzle hole. Even when the nozzle is closed, a method is generally known and used in which inert gas stirs the molten metal in the nozzle hole to prevent solidification.

However, even when using the method of blowing inert gas through porous bricks, it is not possible to completely prevent nozzle clogging, for example when handling high-aluminum killed steel, and clogging occurs because the molten metal entrains the blown gas. Disturbing blowholes occur within the casting, causing a deterioration in the quality of the casting.

An object of the present invention is to provide a method for flowing molten metal from a molten metal container using a sliding nozzle, which eliminates and improves the conventional drawbacks and problems. This object is achieved by providing a method for draining molten metal from a molten metal container that includes anti-occlusion means. That is, the present invention includes an upper plate having a nozzle hole provided at the bottom of a molten metal container, a sliding plate 1,
A method of flowing out molten metal from a metal melting container by sliding the sliding plate to adjustably flow out the molten metal through a sliding nozzle configured by stacking lower plates, a micro-metal having a sliding plate nozzle hole is used. The present invention relates to a method of incorporating a vibration plate, applying micro vibrations with a frequency of 1 Hz or more to the vibration plate, and causing molten metal to flow out from a molten metal container including sliding nozzle blockage prevention means.

Hereinafter, a method of flowing out molten metal from a molten metal container using a sliding nozzle according to the present invention will be explained.

FIG. 1 is a longitudinal cross-sectional view of a sliding nozzle used in the method of flowing out molten metal from a molten metal container by a sliding nozzle according to the present invention, and FIG. 2 is an enlarged view of the plan view taken along the line AA in FIG. 1. Molten metal in molten metal container 8 (not shown)
The continuous casting mold (
(not shown). sliding nozzle 10
are upper plate 5, sliding plate 4. The sliding plate 4 is constructed by stacking three plates, ie, a lower plate 6 and a lower plate 6, and the sliding plate 4 is slid between the upper plate 5 and the lower plate 6 by a sliding drive device 2 such as a hydraulic cylinder. A micro-vibrating plate 3 having the same thickness as the sliding plate 4 is installed in the center of the sliding plate 4, and the vibrating plate 3 is connected to the vibrating device 1 via a connecting member 3a. The vibration device] is fixedly supported by a support plate 4a fixed to the sliding plate 4. The vibrating device 1 is a vibration generating means, such as an electric vibrating device, which is connected to an AC power source via wiring 11, and when the vibrating device operates, it applies a micro-vibration in the direction of the arrow to the micro-vibration plate 3 via the connecting member 3a. It looks like this. A slight gap S is provided at both ends of the micro-vibrating plate 3 in the vibration direction with respect to the sliding plate 4, so that the applied micro-vibration does not directly impact the sliding plate 4. The sliding plate 4 is equipped with a sliding drive device 2, and when the sliding plate 4 is made to slide in the direction of the arrow by operating this, the micro-vibration plate 3 is also slid simultaneously as one unit. The micro-vibration plate 3 is provided with a nozzle hole 3b, and the above-mentioned sliding movement allows the nozzle hole 3b to communicate with, constrict, and further close the nozzle holes 5a and 6a provided in the upper plate 5 and lower plate 6, respectively. It looks like this.

By setting the frequency of the micro-vibration applied to the micro-vibration plate 3 to 1 Hz or more, clogging of the nozzle can be prevented and the level of the hot water can be stably controlled. Third
The figure shows the relationship between the vibration frequency and the hot water level control index (on a scale of 0 to 4, with O as poor level control and 4 as good). Taking the level control index of the molten metal surface as the axis, when the micro-vibration frequency becomes iHz or higher, the generation of a stagnant layer of molten metal can be prevented, and the accuracy of the level control of the molten metal can be increased without causing nozzle clogging; 1. It can be seen that there is not much difference in the effect even if the frequency is increased to 8z or higher.

In the above-mentioned example, a case was explained in which the micro-vibration was applied only to the micro-vibration plate 3, but it is more effective to use a combination of blowing inert gas into the nozzle and vibration by the micro-vibration plate. Figure 4 shows the vibration caused by the micro-diaphragm,
It is an explanatory view when blowing inert gas is used together with porous bricks. In the figure, as in FIG. 1, the vibration device 1. Plate sliding drive device 2. Micro-vibration plate 3.
Sliding plate 4. Upper plate 5°, lower plate 6, immersion nozzle 7. A container nozzle 9 is provided,
Furthermore, a porous brick 12 is fitted into the upper plate 5,
Furthermore, an annular gap 13 and an inert gas introduction conduit 14 are provided on the outer periphery. If the inert gas conduit 14 is introduced into the molten metal flowing into the nozzle of the upper plate 5 while vibrating the micro-vibration plate 3 as shown in the figure, it will have a better effect on preventing clogging of the nozzle. In the figure, the porous brick for inert gas injection is fitted into the upper plate 5.

The porous brick 12 may be inserted into the nozzle 9, not the upper plate 5. The plate 6 may be used, and can be selected as appropriate.

FIG. 5 shows the relationship between the method of the present invention, which uses inert gas injection from the porous bricks 12, and the conventional method, which uses only the injection from the porous bricks 12, with respect to the opening degree of the sliding nozzle. It is.

The horizontal axis is the casting time, and the vertical axis is the opening degree S of the sliding nozzle.
N is an indication. As is clear from the figure, according to the method of the present invention, the opening of the sliding nozzle can be stably maintained because the nozzle is clogged, whereas with the conventional method, the nozzle is clogged and the opening of the sliding nozzle can be maintained stably. The specified molten metal cannot be supplied unless the thickness is gradually increased. FIG. 6 shows the nozzle clogging index (0 when there is no blockage, Fig. 2 is a diagram comparing the cases of complete occlusion (set to 1).

The horizontal axis shows the gas flow rate, and the vertical axis shows the nozzle clogging index.

As is clear from the figure, the method of the present invention in which minute vibrations are applied to the diaphragm has a remarkable effect on preventing nozzle clogging even when the gas flow rate is small.

FIG. 7 is a diagram showing the relationship between the amount of gas blown and the defect index on the skin of the slab (a numerical value proportional to the number of blowholes under the skin). The horizontal axis shows the amount of gas blown, and the vertical axis shows VC @ single epidermis subepidermal defect index. When microvibrations are applied to the diaphragm, the amount of gas blown can be reduced, which has been shown to be effective in reducing defects under the skin of the slab. The present invention is applicable to pouring molten steel from a tundish, or pouring or transferring molten metal from a ladle or other molten metal container into a mold or other container using a sliding nozzle.

(Effects of the present invention) As described above, when the molten metal is flowed out from the molten metal container of the present invention by the sliding nozzle, the molten metal is flowed out while applying a micro-vibration of 1 Hz or more to the micro-vibration plate provided in the sliding nozzle. Ba.

Improves the accuracy of level control of the molten metal surface, prevents nozzle clogging, reduces blowholes caused by external disturbances, and improves quality without changing the sliding nozzle opening or increasing the gas injection amount. Extremely remarkable effects such as improved performance can be obtained.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of the sliding nozzle of the present invention, Fig.
The figure is an enlarged view of the plane taken along arrow A-A in Figure 1, Figure 3 is a diagram of the relationship between the applied frequency of micro-vibration and the level control index, and Figure 4 is the vibration caused by the micro-vibration plate and the inert gas from the porous brick. Fig. 5 is a longitudinal cross-sectional view of a nozzle used in conjunction with blowing;
FIG. 6 is a diagram showing a comparison of the nozzle clogging index when micro vibrations are applied and when no vibrations are applied, and FIG. 7 is a diagram showing the relationship between the gas injection amount and the defect index under the skin of the slab. 1... Vibration device, 2... Plate sliding drive device,
3... Slight vibration plate, 3a... Connection member, 3b.
... Nozzle hole, 4... Sliding plate, 4a... Support plate, 5... Upper plate), 5a... Upper plate nozzle, 6... Lower plate), 6a... Lower plate Nozzle, 7...Immersion nozzle, 8...
Molten metal container, 9... Container nozzle, 10... Sliding nozzle, 11... Power supply wiring, 12... Porous nozzle, 13... Gap, 14... Inert gas conduit. Patent Applicant Kawasaki Steel Corporation 1 Company Representative Patent Attorney Mura 1) Seiji Jido Patent Attorney Takuya Hatano Figure 3 Collar Disgust n Dunhuan (Hz) Figure 6

Claims (1)

[Claims] 1. A sliding nozzle configured by overlapping an upper plate having a nozzle hole provided at the bottom of a molten metal container, a sliding plate, and a lower plate, by which the sliding plate is slid. In a method for letting molten metal flow out from a metal molten metal container in an adjustable manner, a micro-vibration plate having a nozzle hole is incorporated into a sliding plate, and while applying micro-vibration with a frequency of 1 Hz or more to the micro-vibration plate, CLAIMS 1. A method for draining molten metal from a molten metal container comprising sliding nozzle blockage prevention means, the method comprising draining the molten metal.