JPS6040653A - Continuous casting method by vacuum melting - Google Patents

Abstract

PURPOSE:To cast continuously a molten metal with practically no contact with the atm. by maintaining a non-oxidative atmosphere in a vacuum chamber and pouring the molten metal which is vacuum-melted in said chamber into a casting mold in the atm. by an immersion nozzle attached to the stopper of a tundish while pouring the molten metal into said tundish. CONSTITUTION:The inside of a vacuum chamber 1 is evacuated to a vacuum through an evacuating port 3 and a molten metal is vacuum-melted in a melting crucible 2. Gaseous argon is fed through a gas introducing port 4 into the chamber 1 to maintain the atmospheric pressure or higher pressure in the chamber 1 under which the molten metal in the crucible 2 is poured into a tundish 5. A stopper 7 is opened to pour the molten metal by an attached immersion nozzle 8 into a casting mold 9. The molten metal descends as said metal is cast continuously but the nozzle 8 is always submerged under the molten metal surface and the molten metal hardly contacts with the atmosphere. The continuous casting by vacuum melting is thus satisfactorily accomplished.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an apparatus in which a vacuum melting furnace and a continuous casting machine are connected by a stopper that can be opened and closed. The present invention relates to an apparatus which is advantageous in many cases and which not only improves quality and yield but also enables more advanced rationalization than conventional casting methods.

[Background of the invention]

In the conventional vacuum melting/transport casting method, both the melting furnace and the mold were placed in the same furnace, and due to space considerations, the melt weight was limited to relatively small melts. Moreover, after agglomeration,
Since post-processing such as die cutting, feeder cutting, and soaking nine-segment rolling was required, the yield and production efficiency were poor. A method of circulating and degassing in the tundish and then casting it into the casting chamber of a continuous casting machine has been considered, but compared to the present invention, the melting work is done in the atmosphere, and the molten metal in the tundish is Since it is constantly in contact with the atmosphere, its degassing performance is poor.

[Purpose of the invention]

The purpose of the present invention is to melt a test material in a vacuum, promote degassing and homogenization by stirring the molten metal, and then continuously melt the molten metal by casting it into a continuous casting machine connected to a vacuum melting furnace. To,
The purpose of the present invention is to provide an apparatus for producing slabs. According to this device, high-quality products free of gas-induced defects can be produced economically even if they are difficult to dissolve in the atmosphere, with improved yields, resulting in a significant cost reduction.

[Summary of the invention]

In the conventional vacuum melting method, a mold is installed in a furnace, so the space inside the furnace is narrow, and the melting capacity is inevitably limited. In the present invention, only a tanditsu is installed in the furnace,
Since the mold is located outside the furnace, there is more space inside the furnace, and the melting capacity of the melting furnace can be increased. Further, in the conventional ingot making method, there is a reduction in yield due to the riser, a reduction in production efficiency, and difficulty in automation and mechanization, but the present invention can overcome the above points by connecting with a continuous casting machine.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1.2.3. Roughly speaking, the overall structure consists of a vacuum melting furnace and a continuous casting machine. A melting crucible 2 and a tundish for a continuous caster 5 are installed in the vacuum melting furnace, and a stopper 7 for blocking the atmosphere is attached to the tundish. A mold 9, a cooling zone, and a drawing roll 2 are connected to the tundish as in normal continuous casting equipment. Next, its operation will be explained. First, the sample material is melted in a vacuum chamber. At this time, the molten metal is optically stirred to prevent degassing and promote homogenization of the molten metal. After that, Ar gas 4 is fed into the furnace to bring the pressure to the same or slightly higher than atmospheric pressure. Then, the molten metal is gradually poured into the tundish 5, and after an appropriate period of time, the stopper 7 is opened and the molten metal is poured into the mold of the continuous casting machine 9. Thereafter, slabs are continuously produced while being drawn using a drawing device.

FIG. 2 shows the state immediately before the stopper 7 is opened,
From the moment it is opened until the immersion nozzle in Figure 3 is completely immersed in the molten metal, it is in contact with the atmosphere for only a short period of time, after which it is completely shut off. Therefore, according to the fifth embodiment, the molten metal completely solidifies without being exposed to the atmosphere.

〔Effect of the invention〕

According to the present invention, since melting is carried out under vacuum, the molten metal comes into contact with the atmosphere only for a short time from the moment the stopper is opened, and the molten metal is almost completely isolated from the atmosphere.
Effective degassing is possible without contamination from the atmosphere. As a result, nonmetallic inclusions are also reduced. Further, since the molten metal is stirred considerably, the components in the molten metal become uniform, and the yield of added elements (especially active elements) is high and stable. In addition, by connecting to a continuous casting machine, compared to the normal ingot making method, there is no riser, so the yield is high, the slab production time is shortened, and the amount of iron and leggies consumed is reduced. Easy automation 1 It has the advantage of being easy to mechanize.

[Brief explanation of drawings]

All figures show embodiments of the invention *81'! Figure 1 is
The vertical cross-sectional view of the 7f air melting jIlig furnace, Figures 2 and 3 are as follows:
A vertical cross-sectional view of the tundish in the furnace, the immersion nozzle, and the mold of the continuous casting machine. be.

Claims (1)

[Claims] 1. A device consisting of a vacuum melting furnace and a continuous casting machine, characterized by a tundish in the melting furnace and a stopper that can be opened and shut off from the atmosphere between the tundish and the mold of the continuous casting machine. Continuous melting casting method.