JPS6130260A - Molten metal pouring device for twin-roll casting - Google Patents

Abstract

PURPOSE:To provide a titled device which improves the characteristic of a billet by placing a box-shaped side flask with bottom members having the curved surfaces conforming to the roll surfaces of approximately the same length and having an apeture in the middle between a pair of horizontal rotating and casting rolls and maintaining the position where the solidification of the molten metal starts alway below the molten metal surface. CONSTITUTION:The molten metal 3 poured through an immersion nozzle 1 into a flapper nozzle 2 flows out onto the surfaces of the horizontal rotating and casting roll pair 4 through the molten metal outflow aperture 6 between the bottom members 2B having the curves surfaces conforming to the surface of said roll pair 4. The solidification of the molten metal 3 starts always from the roll surfaces at the bottom end of the aperture 6. The intrusion of the molten metal to the molten metal surface part is thus eliminated and the characteristic of the billet is improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pouring device used in a device that continuously casts a thin metal plate by supplying molten metal between a pair of horizontal rolls (double rolls), and particularly relates to The present invention relates to a device capable of stable injection without turbulence in the injection flow.

(Prior art) Molten metal (for example, molten steel, hereinafter simply referred to as molten metal) is supplied from a nozzle at the bottom of the tundish between a pair of horizontal casting rolls arranged with a gap determined according to the thickness of the slab to be cast, and the horizontal rolls are cooled. While driving the solidified thin plate slab, pull it downward.1. Techniques for continuously casting sheet metal are known.

However, when attempting to cast a wide slab with a width of over 1 m using such a casting method,
If the pouring nozzle is positioned at the center of the slab width direction (casting roll axial force direction) and pouring directly between the rolls, turbulence tends to occur in the pouring flow, causing wrinkles in the resulting slab. I don't like it. At the same time, it is also difficult to obtain a wide and uniform pouring flow, and further improvement of the pouring method has been strongly desired.

In addition, in the past, for example, Japanese Patent Laid-Open Nos. 58-47543 and 58-8846 did not use a pouring nozzle with a circular cross section.
As shown in Publication No. 0, a structure in which a frame-shaped pouring device is arranged between horizontal casting rolls is disclosed. Shikaji,
In the former example (particularly Fig. 1), a frame-shaped tundish with an outlet at the bottom is placed on either side of a pair of casting drums (rolls), but the details of its internal structure and functions are not explained here. There is no explanation, and even if the contents of the specification are interpreted in a broad sense, the tundish merely functions to secure a pool of hot water on the top surface of the roll, and it is said to have added special functions such as the device of the present invention described later. It is clearly different.

Also, regarding the latter pouring device, although it is shown as having a frame shape, albeit narrow, this is just a frame and its bottom is completely open, making it different from the device of the present invention. is different.

By the way, as mentioned in Section 2, in such conventional pouring technology, the flow of hot water from the nozzle acts directly on the roll surface, resulting in uneven development of the solidified shell formed on the roll surface. This is a major problem in the twin-roll casting method, as it can induce breakouts and cause wrinkles on the surface of the slab.

(Object of the Invention) The object of the present invention is to provide a pouring device which is completely different from the conventional pouring device described above, and which is capable of stably pouring the molten metal and allows the molten metal to coagulate below the surface of the liquid. It is about providing.

(Structure and operation of the invention) The structure of the twin-roll pouring device of the present invention for achieving this purpose is that a continuous metal pouring device is constructed by having a molten metal injection nozzle facing between a pair of rotating horizontal casting rolls. A thin plate casting apparatus, comprising: a box-shaped side frame having a width approximately equal to the length of the horizontal roll body; and a bottom member having a curved surface along each of the pair of horizontal roll surfaces and having a molten metal outflow opening formed in the middle. A flapper nozzle is disposed between the horizontal casting rolls.

With this configuration of the present invention, the molten metal supplied from the nozzle flows down between the horizontal casting rolls from the molten metal flow mountain opening at the bottom of the flapper nozzle in a wide and uniform stream without producing turbulence or pulsation. , and the bottom member along the roll curved surface of the bottom ensures that the solidification start position moves below the molten metal meniscus (solidification below the surface of the molten metal). As a result, the casting work can be stabilized and the surface quality of the slab can be improved. (Example) The details of the present invention will be explained below with reference to the examples shown in the drawings. FIG. 1 is a schematic diagram showing an example of the pouring device of the present invention.
FIG. 2 is a longitudinal sectional view thereof.

As shown in the drawing, a pair of horizontal casting rolls 4 are rotated in the directions of the arrows at set speeds, and are cooled by a suitable water cooling mechanism (not shown). Further, a pouring nozzle l for supplying molten metal between the pair of casting rolls 4 extends from the bottom of the intermediate container (tundish) toward between the rolls. A box-shaped flapper nozzle 2, which is the main part of the present invention, is arranged between them. Note that 5 is a slab drawn out below the roll 4.

The flapper nozzle 2 is composed of a four-sided side frame 2A forming a rectangular frame body, and a bottom member 2B provided at the lower bottom surface of the side frame 2A. , is formed from two moon-shaped members each extending along the curved surface of the body of a pair of rolls 4 with a molten metal outflow opening 6 in the center sandwiched therebetween. If this bottom member 2B does not exist, the molten metal will contact the roll 4 because it is water-cooled (for example, at the roll position at the lower end of the side frame in FIG. 2).
Coagulation begins immediately, and in some cases this coagulation initiation point y
1 is above the molten metal meniscus, which may lead to deterioration of surface properties. Since the bottom member 2B of the present invention extends from the lower end position of the side frame 2A along the roll body surface, the contact area between the molten metal 3 and the casting roll 4 is reduced, that is, the contact area between the molten metal 3 and the roll 4 is reduced. The contact start position is moved downward so that the solidification start position is always below the molten metal meniscus.

Both the bottom member 2B and the side frame 2A are made of refractories, and the bottom member in particular has superior heat insulating properties and mechanical properties among refractories, and is also resistant to thermal shock. For example, fused quartz (Fused 5il)
ica) Preferably made of something like brick. Further, if necessary, the solidification start position can be adjusted by making the bottom member slidable along the roll surface. As can be seen from FIG. 2, the tip of the pouring nozzle 1 is installed deep within the weir 2, and is immersed in the molten metal during pouring.

During casting, the distance between the pair of casting rolls 4 is set to a predetermined distance, and then the nozzle 1 is rotated at a required speed.
A set amount of molten metal 3 is injected from the molten metal 3 and poured into the flapper nozzle 2. The molten metal 3 accumulates in the flapper nozzle 2 and at the same time flows down between the rolls 4 through the lower opening 6 thereof. At this time, the molten metal 3 comes into contact with the roll surface at the lower end position of the bottom member 2B,
It is immediately cooled and solidified to form a shell, but since the pair of rolls 4 are rotating in the direction of the arrow, the shell moves between and below the rolls and is pulled out according to the roll rotation speed, and the thin slab 5 is can get.

In the above work, the height position of the bottom member 2B is
Set in advance so that the solidification start position is always below the molten metal meniscus.

Of course, the position of this member can be adjusted as appropriate in response to changes in casting conditions.

(Effects of the Invention) As explained above, according to the casting method of the present invention, the molten metal flow supplied to the twin rolls becomes wide and uniform, and turbulence and pulsation of the molten metal are prevented. It is possible to cast high-quality thin metal sheets without causing wrinkles or the like. Furthermore, since the solidification start position is always below the molten metal meniscus, the properties of the obtained slab are also good.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an example of the pouring device of the present invention, and FIG. 2 is a longitudinal sectional view thereof. 1... Immersion nozzle, 2... Flapper nozzle, 3...
... Molten metal, 4... Horizontal casting roll, 5... Slab, 6... Molten metal outflow opening.

Claims (1)

[Claims] In a continuous thin metal sheet casting apparatus configured with a molten metal injection nozzle facing between a pair of rotating horizontal casting rolls, a box-shaped side frame having a width approximately equal to the body length of the horizontal rolls; Molten metal for twin-roll casting, characterized in that a flapper nozzle consisting of a bottom member having a curved surface along the surfaces of the pair of horizontal rolls and having a molten metal outflow opening formed in the middle is disposed between the horizontal casting rolls. Injection device.