JPH01237053A - Plate type liquid film nozzle for continuous casting machine - Google Patents

Abstract

PURPOSE:To make thinning of a cast film to the necessary min. thickness and to prevent variation of molten steel surface and mixture of air bubble into the molten steel by constituting a molten steel nozzle with a nozzle plate. CONSTITUTION:The plate type liquid film nozzle 1 is composed of the nozzle plate 14 extending to inner part of molten steel flow-out hole 12 holding both side edges with one pair of plate-like side plates extended from bottom part of a tundish 6 toward lower part at the both side edges of the rectangular molten steel flow-out hole 12 arranged at the bottom part of the rectangular tundish 6. The nozzle plate 14 is submerged into the molten steel in the straight short side mold. The molten steel 7 in the tundish 6 is supplied into the molten steel in the mold as the liquid film along the surface and the side plate of the nozzle plate 14 after passing through the molten steel flow-out hole 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a molten steel nozzle for a continuous casting machine, and in particular a plate type liquid film suitable for use in a straight short side mold of a belt type thin slab continuous casting machine. Regarding nozzles.

[Conventional technology]

The conventional belt-type continuous thin slab casting machine
As described in Publication No. 03145, in order to immerse the tip of a cylindrical or duct-shaped molten steel nozzle into molten steel in a mold, the distance between the tops of the belts that form part of the mold is widened; A so-called fan-shaped short-side mold with a structure in which the belt interval is narrowed to a predetermined width while gradually changing the curvature from the top is used, or a cylindrical or duct-shaped The tip of the molten steel nozzle was a so-called open nozzle with a structure in which the tip was not immersed in the molten steel, and a so-called straight short-side mold was used in which the belt interval was maintained at a predetermined width from the top.

[Problem to be solved by the invention]

Among the above-mentioned conventional technologies, the fan-shaped short-side mold described in JP-A-60-103145 prevents the generation of solidified shells from molten steel on the fan-shaped short side plate that forms the mold together with the belt and has a curvature. There is a problem that the
On the other hand, the open nozzle disclosed in JP-A-60-152347 has problems such as fluctuations in the molten steel scene (the free upper surface of the molten steel) in the mold and the incorporation of air bubbles into the molten steel. The cause of these problems is that conventional molten steel nozzles are either cylindrical or duct-shaped and supply molten steel from inside the nozzle, which makes it impossible to make the nozzle diameter extremely small, which makes continuous thin slab casting difficult. This is because it is not inherently suitable for the machine.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to create a PB that does not cause any fluctuation in the molten steel scene or air bubbles even in a straight short-side mold suitable for a continuous thin slab casting machine.
11 nozzles.

[Means to solve the problem]

The above object is achieved by configuring the molten steel nozzle with a thin plate, immersing this plate in the molten steel in the mold, and supplying the molten steel into the molten steel in the mold along the surface of this plate.

achieved.

[Effect]

The plate type molten steel nozzle is immersed in the molten steel in the mold, and the molten steel is supplied to the mold as a liquid film along the outer surface of the plate of the nozzle. As a result, the supplied molten steel is quietly supplied into the molten steel in the mold without falling, so the molten steel level does not fluctuate or air bubbles get mixed into the molten steel. Since the wall thickness can be made as thin as necessary within the range that provides the required strength, the belt interval of the straight short side mold can be further narrowed, and it is also possible to obtain a single thin slab using a continuous thin slab casting machine.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a belt-type thin slab continuous casting machine in which a plate 1 and a large wave nozzle 1 of the present invention are combined.

This continuous casting machine includes a pair of endless belts 3 that are positioned opposite each other at a predetermined interval and are synchronously rotated by a guide roller 2.
These belts are provided with straight short-side molds constituted by a pair of rectangular short-side side plates 4 that are in contact with the outer surface of the belt 3 at both side edges near both side edges of the belt. Guide roller 2
A tension adjustment mechanism 5 is provided to adjust the tension of the belt 3 to a predetermined value.

The molten steel 7 in the tundish 6 is passed through the plate type liquid film nozzle 1.
cooling water is injected into the straight short side mold through Stray 1 - The molten steel in the short side mold is cooled and solidified, and the slab 9 is taken out from the mold 1 by the synchronous circulation circuit movement of the bell 1 - 3, and then the cast slab 9 is removed from the mold 1 by a series of guide rollers 1.
0 to move the slab 9 in a predetermined direction. Note that 11 is a machine frame that supports the straight short side mold, cooling pad, etc.

As clearly shown in FIGS. 2A to 2D, the plate type liquid film nozzle 1 according to the present invention has a rectangular molten steel outlet hole 12 provided at the bottom of the rectangular tundish 6, which extends downward from the bottom at both sides of the molten steel outlet hole 12. It consists of a nozzle plate 14 that extends into the molten steel outflow hole 12 with both side edges sandwiched between a pair of plate-shaped side plates 13 . The nozzle plate is immersed in molten steel in a straight short side mold (Figure 1). In this embodiment, the molten steel 7 in the tundish 6 passes through the molten steel outflow hole 12 and is supplied into the molten steel in the mold as a liquid film along the surface of the rear nozzle plate 14 and the side plate 13.

3A to 3D show another embodiment of the plate type liquid film nozzle 1 of the present invention. In this embodiment, the tundish 6 includes a rectangular skirt plate 15 surrounding the molten steel outflow hole 12, a plate-shaped side plate 13 is provided below the skirt plate 15, and a nozzle plate 14 is sandwiched between the skirt plate IS and the side plate 13. Unlike the previous embodiment, the molten steel 7 in the tundish G has a molten steel outflow hole 12. After passing through the skirt plate 15, it is supplied into the molten steel in the mold as a liquid film along the surface of the nozzle plate 14 and the side plates 13.

Still another embodiment shown in FIGS. 4A to 4D differs from the plate-type liquid film nozzle shown in FIGS. 3A to 3D in that liquid film guide members 16 are provided on both sides of the nozzle plate 14 at predetermined intervals. The molten steel in the tundish 6 flows through the molten steel 11i and the outlet hole 12. After passing through the skirt plate 15, the surface of the nozzle plate 14 and the side plate 13. The liquid is supplied as a liquid film along the liquid film guide member 16 into the molten steel in the mold.

The plate type liquid film nozzle 1 in the embodiment shown in FIGS. 5A to 5D is similar to the embodiment shown in FIGS. 3A to 3D, but a plurality of molten steel outflow holes 12 are provided at the bottom of the tundish 6. , for each molten steel outflow hole 12, the third A~
A plate-like side plate 13 similar to that shown in the 3D view. A nozzle plate 14° and a skirt plate 15 are provided. In this embodiment as well, the molten steel in the tundish 6 flows through each molten steel outflow hole 1.
2. After passing through each skirt plate 15, it is supplied into the molten steel in the mold as a liquid film along the surface of each nozzle plate 14 and each side plate 13.

The plate type liquid film nozzle 1 shown in the embodiment shown in FIGS. 6A to 6D is similar to the embodiment shown in FIGS. 2A to 2D, but
A heater 17 is installed inside the nozzle plate 14 and the plate-like side plate 13, and the terminal 18 of the heater is connected to an appropriate heat source (
(not shown). In this embodiment, if the nozzle plate 14 and side plate 13 are preheated, initial solidification of the molten steel being supplied can be prevented.

FIG. 7A to FIG. 7D show a plate type liquid film nozzle according to another embodiment. Although this liquid film nozzle 1 is equipped with the skirt plate 15 as described above, it is not equipped with plate-shaped side plates, and the nozzle plate 14 is held in place by having both side edges thereof sandwiched between the skirt plates 15. .

After passing through the molten steel outflow hole 12, the molten steel in the tundish 6 is supplied as a liquid film along the surface of the nozzle plate 14 into the molten steel in the mold.

The embodiment shown in FIGS. 8A to 8C is similar to that in FIGS. 7A to 7D, except that both surfaces of the nozzle plate 14 are concavely curved, and the molten steel outlet hole 12 has corresponding concave sides. are different. In this case as well, the molten steel in the tundish 6 passes through the molten steel outflow hole 12, forms a liquid film along the surface of the nozzle plate 14, and is supplied into the molten steel in the mold.

〔Effect of the invention〕

According to the present invention, since the molten steel nozzle is constituted by the nozzle plate 1-, the thickness can be reduced to the necessary minimum, so even if the belt width of the straight short side mold is narrowed, the nozzle can be sufficiently immersed into the mold. By supplying the molten steel as a liquid film along the nozzle plate, it is possible to prevent fluctuations in the molten metal level and the incorporation of air bubbles into the molten steel. It has the effect of being castable.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional elevational view of a belt-type thin slab continuous SR machine incorporating the plate-type liquid film nozzle of the present invention, and Fig. 2A is a
A cross-sectional top view showing one embodiment of the plate-type liquid film nozzle of the present invention, FIG. 2B is a cross-sectional elevation view thereof, FIG. 2C is a cross-sectional side elevation view thereof, and FIG. 2D is an A-A in FIG. 2B. 3A is a cross-sectional top view showing another embodiment of the plate-type liquid film nozzle of the present invention, FIG. 3B is a cross-sectional elevation view thereof, and FIG. 30 is a cross-sectional side elevation view thereof, and FIG. 3D diagram 3B A-A
4A is a cross-sectional top view showing still another embodiment of the plate-type liquid film nozzle of the present invention, FIG. 4B is a cross-sectional top view thereof, and FIG. 4C is a cross-sectional view taken along line BB in FIG. 4A. FIG. 4D is a cross-sectional view taken along line A-A in FIG. 4B, FIG. 5A is a cross-sectional top view showing another embodiment of the plate-type liquid film nozzle of the present invention, and FIG. 5B is a cross-sectional top view thereof. Figure 5C is a sectional view taken along the line BB of Figure SA, Figure 5D is a sectional view taken along the line AA of Figure 5B, and Figure 6A is a sectional view taken along the line AA of Figure 5B@. FIG. 6B is a cross-sectional top view showing the embodiment, FIG. 6C is a cross-sectional side elevational view thereof, FIG. 6D is a cross-sectional view taken along A-AM of FIG. 6B, and FIG. 7A is a cross-sectional view of the present invention. FIG. 7B is a cross-sectional top view showing still another embodiment of the plate-type liquid film nozzle, FIG. 7C is a cross-sectional side elevational view thereof, and FIG. 7D is a view taken along line A-A in FIG. 7B. 8A is a cross-sectional top view showing a modification of the plate-type liquid film nozzle shown in FIGS. 7A to 7D, FIG. 8B is a compatible cross-sectional view thereof, and FIG. 8C is a cross-sectional side elevational view thereof. DESCRIPTION OF SYMBOLS 1... Plate type liquid film nozzle, 6... Tandish, 7... Molten steel outflow hole, 13... Plate-shaped collar plate,
14... Nozzle plate, 15... Skirt plate, 16... Liquid film guide member, 17... Heater. 1st (2) 2nd A J 2nd pth 3rd D mouth, /4 Issho = Lu-Gyo 4th B mouth 4c prisoner S A Mouthpiece 5D Kanfu 6 8th mouth 7A figure * 7B mouth 70th Mouth 7th DI. Engineering==61 8th A mouth! Figure 86 Port 8C

Claims (1)

[Claims] 1. At least one nozzle plate extending from the molten steel outlet hole at the bottom of the tundish of the continuous casting machine to the mold of the continuous casting machine, the molten steel flowing from the molten steel outlet hole of the tundish to the mold of the continuous casting machine. A plate-type liquid film nozzle for a continuous casting machine, characterized in that the liquid film is supplied to the mold along the surface of the nozzle plate as a liquid film. 2. A plate-type liquid film nozzle for a continuous casting machine according to claim 1, characterized in that plate-shaped side plates are provided on both side edges of the nozzle plate. 3. A plate for a continuous casting machine in the plate-type liquid film nozzle according to claim 1 or 2, characterized in that a skirt plate surrounding the nozzle plate is provided at the bottom of the tundish. Liquid film nozzle. 4. The plate-type liquid film nozzle according to any one of claims 1 to 3, wherein one or more liquid film guide members are provided on the surface of the nozzle plate. Features a plate-type liquid film nozzle for continuous casting machines. 5. A plate-type liquid film nozzle for a continuous casting machine, characterized in that a plurality of the nozzle plates are installed in the plate-type liquid film nozzle according to any one of claims 1 to 4. membrane nozzle. 6. A plate-type liquid film nozzle for a continuous casting machine according to any one of claims 1 to 5, characterized in that the nozzle plate is provided with a heater. membrane nozzle.