JPH04200847A - Pouring device for thin sheet continuous caster - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a continuous thin plate casting machine with a twin roll type thin plate casting machine that directly casts thin steel plates with a thickness of about 10 mm or less from molten steel. Concerning an improved structure of a pouring device used in a continuous casting machine, particularly an IJ device that supplies molten steel to a sump between water-cooled casting rolls via a pouring nozzle and an inclined plate. This is a secondary proposal.

[Conventional technology]

The thin plate continuous casting machine L is a continuous casting machine that directly casts a material equivalent to a hot rolled plate with a thickness of several millimeters from molten steel, and directly casts slabs with a thickness of about 100 to 300 mm. Compared to a continuous slab caster or a ribbon casting machine that casts cold ribbon of less than 1n+n+, special measures are required for the pouring device. For example, in a continuous slab casting machine, it is sufficient to feed the tundine inner sheet 1 into the mold via an immersion nozzle, so that a special doublet is usually not required for said immersion nozzle. However, in the thin plate continuous casting machine according to the present invention, as shown in FIG.
5. Therefore, if the level of the molten metal in this pool [3] changes due to pouring, it will affect the properties of the solidification shelf that is about to form in contact with the surfaces 7 of these rolls 4 and 5. It will be a failure. As a result, the surface quality of the cast thin steel sheet deteriorates.

For this reason, conventionally, in the pouring device used in this type of continuous casting machine, when the molten steel in the tundish is supplied to the sump through the pouring nozzle, an inclined plate 6 is placed directly below the pouring nozzle 1. The discharge port 2a at the bottom of the pouring nozzle is arranged so that the falling flow of molten steel does not touch the surface of the molten metal in the sump. They were devised in various shapes.

That is, the inventors previously proposed a discharge port having a so-called alligator-shaped opening as disclosed in JP-A No. 2-52153, and achieved a wide molten steel flow and a uniform laminar flow. I tried to change it.

[Problem to be solved by the invention]

However, although the pouring nozzle disclosed in the above-mentioned publication was effective in forming a uniform wide laminar flow, it is difficult to achieve a uniform laminar flow particularly at the width end when making the thin plate to be cast wider. This was difficult to achieve, and there were still issues to be resolved.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pouring device that can overcome the problem faced by the prior art described above, that is, the impediment to wide uniform laminar flow due to the wide width of the slab.

[Means to solve the problem]

The present invention, which was developed to achieve the purpose of lifting, is a pouring device in which molten steel in a tundish is supplied to a pool in a casting roll via a pouring nozzle and an inclined plate placed directly below the pouring nozzle. This pouring device for a continuous thin plate casting machine is characterized in that the lower part of the pouring nozzle is branched into two, and the discharge ports at the tips of each of the branched nozzles are arranged apart from each other in the axial direction of the casting roll. .

[Effect]

The pouring device of the present invention is particularly suitable for over 600 mm and 120 mm.
This is to obtain a stable, uniform laminar flow that spreads in the axial direction of the casting roll when manufacturing a wide thin plate ranging from 0 to 1500 mm.

Now, the present inventors conducted an experimental study on the pouring flow mechanism in the case where pouring is performed in relation to an inclined plate in a pouring nozzle for a twin-roll type direct casting apparatus.

That is, first, the inclination angle of the inclined plate and the expansion angle of the discharge port of the pouring nozzle are determined so that the molten steel flow F on the inclined plate always shows an appropriate spreading width and a uniform flow distribution in the horizontal and vertical directions. We investigated the relationship between them and investigated their appropriate values.

As a result, it was found that the larger the roll width deviation, the larger the expansion angle, and at the same time, it was necessary to suppress the angle of the inclined plate to obtain an appropriate flow of molten steel. In particular, when looking at the flow rate distribution of the molten steel flow at the lower end of the inclined plate, it was found that the flow rate gradually decreases toward the end in the roll axis direction.

From these results, - for boat fishing, the more the casting width (- roll width) is expanded, the more the dispersion and uniform flow distribution of the molten steel flow flowing down the inclined plate will be impaired, and the molten steel flow will be in a desirable state. In particular, the decrease in the flow of molten steel toward the ends in the axial direction of the roll is remarkable.

In response to such a phenomenon, the present invention has a structure in which the lower part of the pouring nozzle is bifurcated, thereby overcoming the drawbacks of conventional nozzles.

That is, the pouring nozzle in the pouring device of this invention is as follows:
As shown in Fig. 1, assuming that an inclined plate is adopted, the lower part of the pouring nozzle 1 installed under the tundish can be bifurcated into two parts, so that the discharge ports 2a and 2b can be spaced apart in the roll axis direction. The molten steel flows exiting these two discharge ports are prevented from interfering with each other. Therefore, by using such a bifurcated nozzle, it is possible to easily expand the distribution width of the molten steel flow rate in the roll axis direction, and it is possible to easily expand the distribution width of the molten steel flow rate to 1200 to 15
It is possible to cope with widening of 00mm. Figure 3 (a
) shows the state in which the molten steel flow F flowing out from one of the sulins 1-2a and 2b, which have curved discharge ports of the two-pronged nozzles IA and IB shown in FIG. 1, flows down on the inclined plate 3, and its width direction. It is an explanatory diagram showing the relationship between position (horizontal axis) and flow rate (vertical axis). As is clear from this figure, when the slit of the nozzle discharge port has a curved shape as shown in the figure, the central part is concave, and as a result, the molten steel in the central part, where the flow rate is high, is directed toward the ends. It has a dispersing effect. As a result, as shown in the figure, the flow rate has a -like distribution in the width direction without showing a concave or convex distribution.

/71') Control the volume flow rate, Tandinjo, 011th. It is preferable to do this by adjusting the opening of the valve provided at 011. The internal flow h of each nozzle can be made into the same branch.

In addition, FIG. 53(b) shows Ninu nozzle IA and 1■3
51 Description of the state in which the molten steel flows F and r flowing out from the slit-like exits 12a and 2h, which form a curved surface, cross the inclined plate 3L, and the relationship between its width direction position and flow rate distribution. It is a diagram. As can be seen from this figure, the molten steel flow discharged from the above-mentioned discharge LI2a, 2b has a curved surface shape, and reaches the end of the inclined plate 3 at both ends Vi:i (lower end of immersion). The molten steel flows merge to form a homogeneous oil, which enables smooth wide casting.

U example) The pouring nozzle shown in No. 1 tg 14 was used in a 60 mm wide twin-roll thin plate continuous casting machine 6 with an angle of θ-20 = 40° (not shown in No. 4 M). Then, the molten stainless steel in the table/dish is continuously injected into the molten metal reservoir 6 in the casting 1-1-rules 4 and 5 at an injection rate of 800 kg/min.
-7.

As a result, a molten metal pool [the part facing the r-1-ru of 5] is formed. 2. Roll axis direction C1' with respect to the generated solidified/solid shell ■;
It was possible to perform injection without causing a non-uniform flow. Moreover, due to the non-uniformity 41- of the solid shell 7, Q is -1('
This saw has been confirmed to be effective in eliminating the occurrence of slab cracking.

Furthermore, C1': Similar casting was carried out using the pouring nozzle 84 shown in Fig. 2 O, 1, and C.
The pouring nozzle 8 has a hollow part with a rectangular cross section 1-7, and the hollow part is cast while keeping the cross-sectional area of the rectangular hollow part constant.
-1- The diameter of the axial direction Jii1 is the discharge opening at the tip of the enema nozzle.
J' and force cylinder are formed so as to gradually increase in the direction of ＼.
PI? 'A widening casting is supported.

〔Effect of the invention〕

This has been explained above. ), according to Unigo's invention, by branching the pouring nozzle into two discharge nozzles and installing them apart in the direction of the roll axis, it is possible to cast a wide thin plate, and the molten steel flowing on the inclined plate can be cast. Since the flow can be made into a uniform laminar flow, wide thin plates can be reliably manufactured with a high yield.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the structure of a pouring nozzle according to the present invention; Fig. 2 is a side perspective view of another pouring nozzle according to the invention; Fig. 4'3 (a); ), (b) respectively shown in Figure 1. 1. The shape of the pouring nozzle and its (2) An explanatory diagram showing the accompanying molten metal flow distribution. Figure 4 shows the pouring pattern as a molten metal pool between the holes. It is a route map of t, 8...Pouring nozzle, 2a, 2b, 9a, 911
-Discharge 1-1, ;)...14Ji swash plate, 4
, 5... Casting roll, (i... Molten metal pool,
7... Solidified shell, F... 7 Yong Steel Flow patent applicant l] Hon Yakin T Gyo Co., Ltd. γ1 Agent Patent attorney Jun Ogawa Agent Patent attorney Morio Nakamura

Claims (1)

[Claims] 1. In a pouring device that supplies molten steel in a tundish to a pool in a casting roll through a pouring nozzle and an inclined plate placed directly below the pouring nozzle, the lower part of the pouring nozzle is bifurcated. 1. A pouring device for a continuous thin plate casting machine, characterized in that the nozzles are branched and the discharge ports at the tips of the branched nozzles are spaced apart in the axial direction of a casting roll.