JPH03110048A - Tundish stopper - Google Patents

Abstract

PURPOSE:To restrain stick and deposition of non-metallic inclusion to both of bosh part of a submerged nozzle and bottom part of a stopper fitting to the both parts by radially arranging plural pieces of penetrated fine holes having the specific diameter from inner hole face toward outer face in horizontal direction to axis of the tundish stopper. CONSTITUTION:The plural pieces of penetrated fine holes 8 having 0.1-0.5mm diameter penetrated from the inner hole 6 toward the outer face over neighborhood position centering the tip part 5 position of the tundish stopper 1, where the fitting part 4 for controlling flow rate of the molten steel is formed at the time of casting, are radially arranged in the radius direction to the axis 8 of tundish stopper 1. In this result, the stick and deposition of non-metallic inclusion developing on the tundish stopper 1 and the fitting part 4 of submerged nozzle 2 is effectively restrained by bubbling of inert gas, and sequential continuous casting operations can be executed to the aimed number of heats, and further as the growth of the inclusion is drastically controlled by restraining stick and deposition of non-metallic inclusion, the quality of cast slab and the yield are improved.

Description

Detailed Description of the Invention (Industrial Application Field) This invention relates to a stopper for a tundish used in continuous casting of metal, that is, a tundish 1-flange, and more specifically to a tundish for molding molten metal. It is characterized by having an inert gas bubbling function to control the amount of flowing down injection and to suppress the deposition of non-metallic inclusions in the steel on the refractory placed in the molten metal flow path from the tundish to the mold. This relates to a tundish stopper for continuous casting.

(Prior Art) The conventional technology will be described using continuous casting of steel as an example. Continuous casting tandem tube.

It is used to adjust the amount of molten steel injected from the tundish into the mold during continuous casting operations, and to stop the injection when the casting is finished. Conventionally, the entire length of the molten steel is divided into fixed dimensions. There are two types: an integrated type and an integrated type, and the present invention is primarily directed to an integrated tundish stopper (referred to as a long stopper). (Hereinafter referred to as a tanditshu stopper.) Conventionally, in continuous casting of steel types such as aluminum killed steel and silicon killed steel where the molten steel to be cast contains non-metallic inclusions, the casting is performed many times in succession over a long period of time. When it happens,
Since inclusions gradually accumulate in the inner hole of the immersion nozzle located between the tundish and the mold, that is, on the molten steel flow path surface, and it becomes impossible to maintain the continuation of casting, the tip 5a of the tundish stopper (long stopper) la shown in FIG. A method of bubbling inert gas from the inner hole 6a side from the gas bubbling gas blowing hole 7 into the inner hole 3 of the submerged nozzle 2 shown in FIG.
To the inner hole 3 of the immersed nozzle 2 The inner hole 3 of the immersed nozzle 2
Slit-type immersion nozzles, which flush out inclusions by bubbling inert gas such as argon gas from a gas reservoir installed on the wall through the pores of the inner hole wall, are used to prevent non-metallic inclusions from accumulating. It is well known that it is used as a means for

For each of the above methods, various conditions for continuous casting operations are required: steel type, t4 production rate, molten steel temperature.

Bubbling of inert gas according to the casting time, flow rate of molten steel in the inner hole 3 of the immersion nozzle, mold powder composition and amount used, etc., that is, the application position and range of bubbling, the type of inert gas, bubbling pressure and its flow rate, etc. , and by delicately controlling the balance of the amount of bubbling of inert gas between the tip 5a of the tundish stopper 1a and the inner hole 3 of the immersion nozzle.
In the vertical inner hole 3 of the immersion nozzle 2, we were able to suppress the adhesion and accumulation of nonmetallic inclusions and increase the number of castings to a certain extent, but the target level was not reached. be. This is because no measures have been taken to prevent the non-metallic inclusions from accumulating in the top morning glory part, which is the fitting part 4 with the tundish stopper 1a other than the vertical inner hole part 3 of the immersion nozzle 2. stopper
18, the main purpose of flow rate control becomes ineffective, and the flow rate itself decreases, and due to this factor, continuous casting operations with multiple continuous casting operations for a long time are obstructed, and this part is forced to be limited. The resulting deposits peel off and become entangled in the slab, which has a significant negative impact on quality and yield, and raises operating costs, leaving many important issues unsolved.

(Problem that the invention attempts to solve) Similarly, continuous casting of steel will be described as an example.

As mentioned above, when casting aluminum-killed steel, silicon-killed steel, etc., continuous casting is performed many times over a long period of time, and non-metallic inclusions accumulate over the entire length of the immersion nozzle, resulting in nozzle blockage, control disturbances, and slab quality. This has a total negative impact on continuous casting operations, such as a drop in yield and a decrease in yield.In this regard, this invention aims to eliminate non-metallic materials in both the top part of the immersion nozzle and the bottom part of the fitting tundish stopper. This was done to suppress the adhesion and accumulation of inclusions.

To prevent non-metallic inclusions from adhering to the Dan Date Shuttle stopper, as mentioned above, the single gas blowing hole 7 provided at the tip of the bottom is used.
This is due to the bubbling of inert gas from the embedded porous plug 7', and these are caused by the adhesion and accumulation of non-metallic inclusions at the fitting part 4 between the tundish stopper 1a and the morning glory part of the immersion nozzle 2. It has no suppressive effect at all.

In this invention, the above-mentioned tandish stopper is limited to
18 Suppresses the adhesion and progress of deposition of non-metallic inclusions at the fitting part 4 between the bottom part and the top bosh part of the immersion nozzle 2, and prevents other known various types of inclusions in the vertical inner hole 3 of the immersion nozzle 2. By combining this method with a method to suppress the adhesion of inclusions, the aim is to achieve smooth operation by maintaining slab quality and yield within acceptable levels during continuous casting over a long period of time.

(Means for solving the problem'4) This invention! It was created to solve the problems of VJ*r, and consists of the following J.

That is, the tundish stopper of the present invention has a plurality of 071 gas bubbling holes near or above the fitting part with the 1-tube face part of the immersion nozzle in the molten steel flow rate point D-hole during casting. Purchase-〇. 5
A circular or polygonal through-hole with a diameter of about 100 mm on one side is made 14 times radially to the center of the tandissic axis, and 30 times each in the vertical direction relative to the horizontal line toward the lower blade. ', 3-dimensional directions are arranged on the slope within a range of 45° on each side according to the operating conditions.
．． Furthermore, if necessary, the necessary amount of inert gas introduced into the tundish stopper from the inert gas supply device N is applied to the outer surface from the inner hole at the necessary pressure by placing the inert gas locally in a selected manner. The method aims to "bubble" toward the M-method and solve the above-mentioned problems.

Here I will explain the reason for the limitation. First, set the size of the through pore to 00
1m - 0.5m was chosen because it was impossible to manufacture anything less than 0.1m, so it was set within 0.5m, and the reason was to apply inert gas to the inner hole of the tundish stopper with a back pressure suitable for casting. This is because even if the molten steel is fed into the tundish, the head pressure of the molten steel in the tundish will cause the molten steel to flow back into the inner hole of the tundish.

Further, the arrangement angle of the through-holes was set within 30° in the vertical direction and within 45° in the horizontal and horizontal directions because of manufacturing limitations.

This invention will now be described with reference to Drawing No. 1, 4゜5.6 for Embodiment L3.
, 7.8 will be explained with reference to Figures.

〔Example〕

First, the tundish stopper 12 is an immersed nozzle made of alumina graphite.

In Fig. 1, the flow rate control of molten steel during casting 1 - the area 6 in the vicinity of the tip 5 of the tandem steel collar 1 which becomes the fitting part 4 in the roll, i.e. 10I downward and 20I upward.
0Wl], its thickness is 0.1n++n-08
Inner hole 6 in which the cross-sectional shape of f is circular or polygonal in 5 cars.
From the outer surface 1. A through hole 1 ((1) having a plurality of holes 9, 9' radially radially upward and downward at an angle of 30 degrees with respect to the axis 8 of the tundish stopper 1,
The radiation angle can be set to the left or right, or in a three-dimensional direction depending on the casting conditions within a range of 45 degrees, and it is also possible to combine various angles, so that the multiple through holes 9 and 9' are each constant. The holes are spaced apart from each other to form through-pore zones.

(Figs. 6 and 7) In the embodiment shown in Figs.
radially downward 3 in the radial direction with respect to the axis 8 at the tip 5 of the
A plurality of through holes 9 are provided at an angle of 0°.

In addition, Figure 6.7 shows an example of an arrangement in which only one side is placed, and although the inert gas bubbled through the through hole 9' varies depending on the casting conditions, most of it is drawn into the immersion nozzle side by the molten steel. The purpose of the present invention is achieved, and the remaining portion rises to the surface of the hot water, is captured by the nonmetallic inclusions, and floats to the surface of the hot water, developing a molten steel cleaning effect.

Is Fig. 8 (a) the axis of the tanditshu stopper 1? In the case where a plurality of through holes 9 are provided radially, Figure (b) shows a radiation angle of 45 to the left and right with respect to the coaxial core.
Examples are shown in which they are arranged in an angular range of .degree.

(Effects of the Invention) The effects of the present invention based on the examples are that the adhesion and accumulation of non-metallic inclusions occurring at the fitting part of the dungeon stopper and the immersion nozzle can be effectively suppressed by bubbling of inert gas, and continuous casting can be improved. The target number of operations is possible, and the growth of inclusions is greatly suppressed by suppressing the deposition of non-metallic inclusions.As a result, the size of inclusions caught in the slab is miniaturized. 5 The size is eliminated without affecting quality, and there is no decisive effect on slab quality and yield.

This will have the effect of improving both.

Furthermore, compared to the conventional method, continuous casting can be performed for a longer period of time, and the operating cost can be reduced by 11 times, which brings about significant effects.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing the connection between the tundish stopper and the immersion nozzle, Figs. 2 and 3 are longitudinal sectional views of the conventional tundish stopper, and Fig. 4 is an implementation of the tundish stopper of the present invention. A longitudinal cross-sectional view showing an example, Fig. 5 is an open bottom view, Fig. 6 is a front view of an embodiment of sentencing, Fig. 7 is a longitudinal sectional view of the same, Fig. 8 α), @ is another embodiment of the same FIG. 1.1a... Tandish stopper 2... Immersion nozzle, 3... Inner hole part, 4... Fitting part, 5, 5a.
... Tip, 6, 6a... Inner hole, 7... Gas blown single hole, 7'... Embedded porous plug, 8... Shaft core, 9
,9′...through pore,

Claims (1)

[Claims] 1. 0.1 to 0.5 m radially from the inner hole surface toward the outer surface in the horizontal direction with respect to the axis of the tundish stopper.
A tundish stopper characterized by having a plurality of through holes of /m. 2. The tundish stopper according to claim 1, wherein the through holes are arranged at an angle of 30 degrees in the vertical direction of the horizontal line with respect to the stopper axis. 3. The tundish stopper according to claim 1, wherein the through holes are arranged at an angle of 45 degrees to the left and right with respect to the stopper axis in a horizontal cross section of the stopper. 4. The through-holes are arranged at a combined angle of 30° vertically to the horizontal line and 45° horizontally to the left and right in the horizontal section of the stopper. The tundish stopper according to claim 1. 5. The tundish stopper according to claim 1, wherein the through-holes are locally limited in the horizontal and vertical directions.