JPH0217734Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) This invention is used to prevent oxidation and scattering of molten metal and to prevent non-metallic inclusions from being entrained when pouring molten metal from a ladle into a tundish during continuous casting operations. This invention relates to an improvement in a tandice pot used for the purpose of. (Prior art) Conventionally, refractories used for purposes such as non-oxidizing injection of molten metal from a ladle into a tundish in the continuous casting method are mainly made of fused silica, graphite alumina, etc. with long nozzles. As shown in Figure 1, it was attached directly to the bottom of the ladle and used in a sealed state. In addition, the tundish pot shown in Figure 2 has been used to improve opening operability when the natural opening ratio of the ladle is low, or when it is difficult to use a long nozzle due to equipment space constraints. Ta. Incidentally, to explain the details of the drawing of the conventional one, the first
In the figure and FIG. 2, 1 is a ladle, 2 is an upper nozzle, 3 and 4 are sliding nozzles, 5 is a collector nozzle, 6 is a long nozzle, 7a is a tundish pot, 11 is a tundish pot, and 12 is a tundish pot. 13 indicates a molten steel, and 14 indicates a seal curtain. Note that the tundish pot 7a shown in FIG.
is used without directly touching the ladle 1, and there is a space between the ladle 1 and the tundish pot 7a.
This method maintains a perfect seal by sealing the space at step 4 and filling the space with inert gas. In this tundish pot, the splash generated when pouring molten metal adheres to the inner wall of the pot and accumulates on the inner wall of the pot, causing a problem in operation, so the shape shown in Fig. 4 was changed from the initial shape (Fig. 3) for the purpose of suppressing metal adhesion. That is, improvements have been made to a tapered type with a wider bottom shape. However, the effect of suppressing the adhesion of base metal in this improvement is not fully satisfactory, and since the tapered shape increases the turbulence of pouring and molten metal flow in the immersed part of the tundish, The slag line of the tandate pot has become noticeably eroded, and it has been forced to be discarded due to eroding or holes, and stable repeated use is limited to a certain limit due to the quality of cast metal and cost reduction. Further improvements and refinements have been awaited. Note that the tundish pot 7a shown in FIG. 4 is improved from the initial shape described above.
We will discuss the problems in this case. (b) The amount of metal attached is less than 50% compared to the initial level, but it is still not enough to satisfy 1 cast (4 to 6 channels). (b) Because the slag line has a wide taper at the bottom, it tends to cause hot water turbulence 18 (Fig. 5) in the immersion part, which becomes large enough to be discarded within two casts. (c) Because metal adhesion on the upper part of the tundish pot 7a progresses significantly, stable casting of 3 channels or more is difficult, and the life of the tundish pot 7a is thereby limited. Next, the state shown in FIG. 5 in the case of the tundish pot 7a shown in FIG. 4 will be explained. First, the molten steel injection stream 15 is injected from the ladle, falls into the tundish, becomes the molten steel flow 16 in the tundish, and flows out from the tundish pot 7a. At this time, the tandate pot 7
Since the inclination angle 17 between a and the vertical line 10a is 5 degrees, the flow causes turbulent flow 18 on the outer surface of the pot, resulting in severe erosion of the immersed portion of the pot. (Slag line melting loss) (Technical issue) Therefore, this idea solves the problem of 3 discontinuities by preventing the conventional drawbacks from adhering and accumulating metal, and greatly improving the tundish life by suppressing the melting loss of the slag line. The technical problem is to provide a tandy pot that can be used many times. Specifically, by making the inner surface of the tundish pot into a spherical bottom wide shape, splash adhesion (particularly in the upper part) is prevented, and turbulence of molten steel near the slag line is suppressed to reduce melting loss. This allows for multiple discontinuous uses. (Technical Means) To explain the tundish pot of this invention in detail with reference to the embodiment shown in FIG. Expand the flange part 8 downward by 10 to 30% of the inner diameter ratio,
A rounded surface 9 is formed, and the following is approximately vertical, and only the inner surface is tapered slightly wider at the bottom.
That is, with the inner surface shape set for use,
A rounded surface that expands downward in a spherical shape is formed on the upper inner surface to form a downwardly divergent shape. The inner surface taper angle θ is inclined outward by 1.5° with respect to the vertical line 10. In addition, the expansion dimension from the bottom of the flange part 8 is set to 10 to 30% on one side of the flange diameter ratio. If it is less than 10%, the effect of preventing metal attachment will be small, and if it is more than 30%, the shape will become large and the tundish pot cost will increase. This is because there are problems such as the large rise in height and restrictions on how to attach it to the tundish at the time of setting. In addition, the reason why only the inner surface of the area below the enlarged spherical inner diameter part is tapered outward by 1.5° from the vertical line 10 is because it is difficult to remove the bare metal during repeated use, as opposed to the slight build-up that occurs when vertical. , if it is 1.5° or more, a wider taper shape is required for the outer surface due to the balance of wall thickness in terms of strength of the tundish pot, which causes turbulence in the flow of molten steel injected inside the tundish pot and shortens the life. This is because it becomes difficult to use it many times and cannot contribute to cost reduction. (Effects) Since this device has the above-mentioned configuration, it can prevent the accumulation of metal, reduce the erosion of the slag line, and greatly improve the life of the tundish, making it possible to use it many times discontinuously. can. Next, the effects of this invention will be described with reference to examples.
The number of pots is 70 tons, and one casting is equivalent to 6 to 7 cups of pots.
This refers to the case of continuous casting of cups, and an example of use for special steel is shown below.

【table】

[Table] As shown above, the amount of metal deposited at one time is small, and the erosion of the slag line is also extremely small, resulting in discontinuous
It became possible to use it ~8 times.

[Brief explanation of the drawing]

Figure 1 shows a ladle using the conventional long nozzle method.
Figure 2 is an assembly diagram of the tundish pot usage method, Figure 3 is an enlarged vertical cross-sectional view of the initial tundish pot, and Figure 4 is an enlarged vertical cross-sectional view of the conventionally used tundish pot. , FIG. 5 is a diagram showing the formation of turbulent flow of poured molten steel in the tundish, and FIG. 6 is an enlarged longitudinal sectional view of an embodiment of the tundish pot. 1... Ladle, 2... Upper nozzle, 3, 4... Sliding nozzle, 5... Collector nozzle, 6
...Long nozzle, 7,7a...Tandish pot, 8...Flange part, 9...Round surface, 1
0, 10a...Plumb line, 11...Tundate dish, 12...Tundate dish cover, 13... Molten steel, 14...Seal curtain, 15...Injection flow,
16... Molten steel flow in the tundish, 17... Inclination angle, 18... Turbulence, θ... Angle.

Claims (1)

[Scope of utility model registration request] A tundish pot used for non-oxidizing injection of molten metal into a tundish from a ladle in continuous casting of molten metal, etc., has a flange on the upper inner surface when its inner surface is set for use. It is characterized by forming a rounded surface that expands into a spherical shape in the range of 10 to 30% of the inner diameter of the part, and forming a downwardly widening shape with an inner taper angle of 1.5 degrees outward from the vertical line. and a tandate pot.