JPH079088A - Production of cast billet by continuous casting equipment for producing small lot - Google Patents

Abstract

PURPOSE:To reduce scrap quantity at the time of changing a kind of steel in a continuous casting for producing a small lot. CONSTITUTION:Plural molds 10 for continuous caster are laid on a turn table 8 and this turn table 8 is rotated, and by connecting the molds 10 with a tundish 2 through a runner 6, while changing over in order, the cast billet are produced. Therefore, at the time of changing the kind of steel, as only the molten steel remained in the runner 6 becomes the scrap, the scrap quantity at the time of producing many kinds in small quantities is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a slab using a continuous casting facility for small lot production.

[0002]

2. Description of the Related Art Usually, a continuous casting method called continuous casting is adopted for small-volume production of various kinds such as different steel types in a continuous casting facility. In such an operation, since a plurality of steel types are continuously poured, a mixed state of different steel types occurs at the boundary. Since this mixing part has a different content from the type of steel to be cast, it is generally scraped, and in order to prevent mixing, it is possible to keep the mixed state as much as possible by interposing a connecting metal fitting such as a steel plate partition plate. Hold down. Therefore, there is a problem that a large amount of scrap is generated in the continuous casting method for different steel types. In addition, when inserting the connecting metal fittings, casting is stopped during the insertion, so the casting efficiency is reduced, and when comparing the slabs of the steady and unsteady parts, there is a difference in the slab's internal quality (center segregation). In particular, high-grade steel materials are difficult to use and have to be scrapped.

Therefore, regarding small-lot production, the applicant of the present invention provided a single tundish shared by a plurality of strands in a multi-strand type continuous casting facility,
This tundish is divided by a weir for division into chambers for each strand, and each divided chamber is provided with a tundish nozzle, and at least one of these chambers is filled with an additive hopper and gas bubbling. A tundish for small lot production is proposed, in which a device is provided and molten steel is supplied from one ladle over the dividing weir to each chamber (see Japanese Patent Laid-Open No. 2-99251).

However, when the small lot production is carried out in a room provided with a hopper for introducing additives, etc., the tundish for small lot production proposed as described above is also a small lot like the continuous casting method of different steel types as described above. Before and after the production, there was a problem that a mixed boundary portion was generated in the mold, and the generation of a scrap slab was inevitable.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist thereof is: 1) a continuous casting facility comprising a ladle, a tundish and a mold. , A plurality of the molds are placed on a turntable, the turntables are rotated, and the molds are sequentially connected to the tundish via a runner to connect and pour water. In the method for producing a slab using a continuous casting facility for small-lot production, which is characterized in that: This is a method for manufacturing a slab using a continuous casting facility for small lot production, which is characterized by rolling.

[0006]

The present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is an overall schematic view of an embodiment of the present invention, FIG. 2 is a main part view as seen from an arrow A in FIG. 1, and FIG. 3 is a detailed view of the main part of FIG.

[0007] This embodiment is a continuous casting facility for producing small lots using a normal steel type changing method in a tundish or a tundish refining method. In the tundish, molten steel poured from a ladle is used. In addition, a predetermined alloy is added and stirred, or a molten alloy is added to adjust the composition of the molten steel.

In FIG. 1, 1 is a ladle, 2 is a tundish, 3 is a hopper for adding an alloy, and the tundish 2 is provided with a gas bubbling device (not shown) so as to uniformly stir molten steel. It has become. Reference numeral 4 is a ladle nozzle, and 5 is a sliding nozzle.

The sliding nozzle 5 communicates with the inlet portion 6a of the L-shaped runner 6 in a state of being shielded from the outside air. The inlet 6 b provided at the outlet of the runner 6 communicates with the communication port 9 provided in the turntable 8 via the partition plate 7 and the fixed plate 21. The communication ports 9 are provided according to the number of the molds 10 placed on the turntable 8, and the mold 10 is mounted on each of the communication ports 9. That is, in this embodiment, as shown in FIG. 2, eight molds 10 are radially mounted on the turntable 8 at equal intervals. The turntable 8 is provided with a gear on its outer peripheral surface. A motor 12 that controls this gear through a pinion 11 by a signal from the CPU.
The turntable 8 is intermittently rotated by means of the intermittent drive.

The fixing plate 21 is provided with a through hole 22 communicating with the injection port 6b. The through hole 22 is selectively communicated with the communicating hole 9 by the rotation of the turntable 8. It is like this. The partition plate 7 is provided with a partition plate actuator 13. A discharge port 14 is opened at the bottom of the L-shaped runner 6, and a plug body 15 is provided at the discharge port 14. Further, as shown in FIG. 3, the mold 10 is vertically separable into two and is opened and closed by a pair of opening and closing cylinders 16. Also, this mold 10 is
Although not shown, the temperature control (cooling) medium passage is buried,
Further, if necessary, an electromagnetic stirrer may be attached to improve the quality of the slab. In addition, in this mode 10,
Although not shown, when it is rotated in the cooling zone, cooling water may be sprayed to cool it.

In FIG. 1, numeral 17 is a roller which is constructed so that it can be lightly reduced.
On the roller apron 17, a slab crane (not shown) is provided on the roller apron 17 for gripping and inserting the slab cast in the mold 10. And this roller apron 17 is connected to the usual rolling equipment used for the ingot making method.

Next, the operation of this embodiment will be described. First,
Described below is the case of continuously producing ingots of the same steel type. The molten steel 18 is poured from the ladle 1 into the tundish 2, and the alloy 19 is added to the molten steel 18 as necessary and stirred. The molten steel with this composition adjusted passes through the runner 6,
Through hole 22 and turn table 8 provided in fixed plate 21
For example, the molten metal is poured from below the mold 10x in which the release agent has been sprayed beforehand through the communication hole 9 provided in the.
When pouring is completed in this mold 10x, turntable 8
Is rotated by a predetermined pitch. As a result, first, the through hole 22 and the communication hole 9 of the mold 10x are blocked, and when further rotated, the communication hole 9 and the through hole 2 of the next mold 10y.
2 is communicated with, and molten steel is poured into the mold 10y.

On the other hand, the mold 10x poured earlier is coated with a powdery heat insulating material 20 to delay the occurrence of skinning on the upper surface of the molten steel. Then, the molten steel of the mold 10x is transferred to a cooling zone and cooled. And this mode
When the cylinder 10x is transferred to the mold release zone, the mold is opened by the opening / closing cylinder 16 and the slab is conveyed to the roller apron 17. The slab is lightly rolled by the roller apron 17. By the light reduction rolling with the roller apron 17, the slab can avoid the sink mark caused by the solidification shrinkage during the normal ingot casting, so that the cast slab can be cast without loss due to the sink mark. At this time, the cast piece inserted into the roller apron 17 is determined by the elapsed time from the completion of pouring into the mold 10 and the calculation of the solid fraction inside the cast piece by the temperature of the mold surface. Timing is decided. In this way, another model 10y
Alternatively, the cast pieces cast by the next mold 10 are intermittently inserted into the roller apron 17 to successively produce predetermined cast pieces.

Next, the case of changing the steel type will be described. The remainder of the molten steel of the type of steel that has been cast until now is molded 10
I will pour it in. Then, the sliding nozzle 5 of the tundish 2 is closed, the turntable 8 is rotated by a half pitch, and the fixing plate 21 is used to inject the injection port 6 of the runner 6.
b is cut off from the communication hole 9. Then, the stopper 15 is opened. As a result, the existing steel types remaining in the runner 6 are discharged. During this time, new molten steel is poured into the tundish 2 from the ladle 1, and the alloy 19 is added so as to be a constituent of the steel type to be cast next. When the molten steel of this new component is refined, the plug 15 is closed and the sliding nozzle 5 is closed.
When the turntable 8 is rotated and the mold 10 is fitted to the inlet 6b, molten steel having a new component is poured into the mold 10. Here, when the plug 15 is opened, the molten steel discharged from the discharge port 14 is about 1 to 2 ^ton.
Therefore, for example, in comparison with the proposed scrap amount of 20 to 40 ^ton described in Japanese Patent Laid-Open No. 2-99251,
Much reduced.

Although the runner 6 of the present embodiment is of the down pouring type, the present invention is not limited to this and may be of the top pouring type. Also, the mold 10 of this embodiment is a turntable 8.
However, the present invention is not limited to this, and may be set back and forth on the rail and set at the inlet 6b.

[0016]

EFFECTS OF THE INVENTION According to the present invention, since molten metal is poured from a sliding nozzle of a tundish into a plurality of molds via a runner, only the molten steel remaining in the runner is changed when the steel type is changed by small lot production. Since it becomes scrap, the quantity can be made extremely small and the quantity of scrap at the time of high-mix low-volume production can be greatly reduced.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of an example of the present invention.

FIG. 2 is a main part view as seen from an arrow A in FIG.

FIG. 3 is a detailed view of a main part of FIG.

[Explanation of symbols]

1 ... Ladle, 2 ... Tundish, 3 ... Additive alloy feeding hopper, 5 ... Sliding nozzle, 6 ... Runner, 8 ... Turntable, 10 ... Mold, 17 ... Roller apron

Claims (2)

[Claims] 1. A continuous casting facility comprising a ladle, a tundish, and a mold, wherein a plurality of the molds are placed on a turntable and the turntable is rotated, A method for producing a slab by a continuous casting facility for small-lot production, characterized in that a mold is successively switched and connected to the tundish through a runner to pour the molten metal. 2. A slab cast by the mold according to claim 1, which is inserted into a roller apron and subjected to light reduction rolling to produce a slab by a continuous casting facility for small lot production. Law.