JPH029901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tundish in a continuous thin metal plate casting apparatus.

Twin roll type and twin belt type synchronous continuous casting machines are generally known as equipment for continuously casting thin plates of 1 to 10 mm directly from molten metal. In these continuous thin plate casters (thin plate continuous casters), the casting speed is several tens of times higher than that of conventional continuous slab casters in order to maintain the same production volume as before. Therefore, in continuous thin plate casting, it is important to control the initial solidification state, and it is necessary to appropriately control the solidification shell growth rate. That is, especially in the case of the twin roll method, if the solidification is completed too early, it will be difficult to pull out the plate, and if the solidification is completed too late, the plate may bulge or break out. Therefore, it is necessary to reduce the degree of superheating of the molten metal and form a uniform solidified shell in a short time. However, with the tundish included in conventional continuous casting machines, it is difficult to maintain a small degree of superheating and control the degree of superheating with high precision to enable continuous casting of thin sheets.

Also, unlike the mold section of a conventional continuous caster, the casting nozzle of a thin plate continuous caster does not have the function of floating and separating non-metallic inclusions in the molten metal. There is no residence time. That is, non-metallic inclusions introduced into the casting nozzle are trapped in the solidified shell, resulting in product defects. Therefore, there is a need for a tundish that can separate and remove non-metallic inclusions more effectively than conventional tundishes.

The present invention has been made in order to solve the above-mentioned problems, and provides a tundish that can supply molten metal with a small degree of superheating and small variations in the degree of superheating, and with non-metallic inclusions sufficiently floated and separated, to a continuous thin plate caster. The purpose is to provide

According to the present invention, by means of a weir that divides the surface of the molten metal and communicates it at the bottom, a small volume receiving chamber that receives the molten metal from the ladle and a large volume molten metal supply chamber that supplies the molten metal to the continuous casting device are provided. There is provided a tundish for continuous metal casting, which is characterized in that the tundish is separated, is provided with a heating means and a stirring means for providing a circulating flow in a hot water supply chamber, and further has a valve means and a nozzle at a supply port for molten metal.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The tundish container consists of an iron shell and a refractory material inside, and is divided into two large and small chambers by refractory weirs 9 and 9'. The weir 9 that divides the surface of the molten metal is essential, but the weir 9' standing from the bottom may not be provided. The chamber with a small volume is a hot water receiving chamber 10, and the chamber with a large volume is a hot water supply chamber 11. A channel type induction furnace 12 is installed on the side wall of the hot water supply chamber, and an electromagnetic stirring device 13 is installed on the opposing side wall. A slide valve 14 is provided at the molten metal supply port at the bottom of the hot water supply chamber, and a pouring nozzle 8 is further connected thereto. The pouring nozzle faces a twin-roll or twin-belt mold (not shown) for continuous casting.

Note that the hot water receiving chamber 10 and the hot water supply chamber 11 are covered with a lid 15, and the interior thereof is made into an inert gas atmosphere using Ar or the like. Molten metal 16 from ladle 17 to receiving chamber 10
to float the nonmetallic inclusions 18 at this point. The molten metal 16 passes through the gap 23 between the weirs 9 and 9' and moves to the hot water supply chamber 11. Before starting casting, the slide valve 14 is closed, and the molten metal is stored until it reaches a predetermined head 19. At this time, the hot water level is detected by a hot water level detector 22 installed on the side wall of the tundish. There, the temperature is measured continuously or intermittently by a thermocouple 20, and the channel-type induction furnace 12 heats it until the target temperature is reached. Thereafter, the temperature measurement results are fed back for power control of the channel type induction furnace 12. In order to prevent the temperature of the molten metal in the hot water supply chamber from becoming non-uniform depending on the position, a weak circulating flow 21 is applied to the molten metal by an electromagnetic stirring device 13 as shown in FIG. At this time, use weak stirring to prevent inclusions from being re-involved. Since the amount of molten metal accommodated in the hot water supply chamber is sufficiently large, sufficient residence time of the molten metal is provided for inclusions to float and separate in the hot water supply chamber. Furthermore, since a heating device is provided, there is no need to worry about the temperature of the molten metal dropping, and the molten metal can stay there for a long time.

When the molten metal temperature reaches the target temperature, slide valve 1
4 and start casting. The hot water supply speed is adjusted by changing the opening area of the slide valve 14. The molten metal capacity of the hot water supply chamber is made large so that the temperature of the molten metal in the hot water supply chamber is not greatly disturbed by the molten metal flowing from the hot water receiving chamber. Due to the above-mentioned reasons, the head 19 becomes large, which tends to cause uneven temperature of the molten metal in the vertical direction, so the electromagnetic stirring device 13 is provided. The molten metal outlet at the bottom of the hot water supply chamber may be located at the lower part of the side wall of the tundish and extend horizontally. Further, the valve at the molten metal outlet may be a stopper as shown in 24 in FIG.

According to the present invention, it has become possible to supply a molten metal with a low degree of superheating and a small variation in the degree of superheating to a continuous thin plate caster. In addition, a clean molten metal with few nonmetallic inclusions can be obtained at the same time. The present invention solves the problems of plate shape and inclusions, which are important problems in continuous thin plate casting, and also significantly improves operability.

The tundish according to the present invention can be used not only in continuous thin plate casting machines such as twin-roll and twin-belt systems, but also in conventional continuous casting machines.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a vertical cross-sectional view of an apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the apparatus of FIG. 1, and FIG. 3 is a partial cross-sectional view of a stopper. . In these figures, 10: hot water receiving chamber, 11: hot water supply chamber, 8: pouring nozzle, 9, 9': weir, 12: heating means, 13: stirring means.

Claims (1)

[Claims] 1 A weir that divides the molten metal at the surface and communicates it at the bottom divides the molten metal into a small volume receiving chamber that receives the molten metal from the ladle and a large volume hot water supply chamber that supplies the molten metal to the continuous casting equipment. 1. A tundish for continuous metal casting, characterized in that the tundish is provided with a heating means and a stirring means for providing a circulating flow, and further has a valve means and a nozzle at a molten metal supply port.