JPS6277152A - Method and apparatus for continuous casting of thin sheet using twin rolls - Google Patents

Abstract

PURPOSE:To provide sure sealing between twin rolls and dams by blowing an inert gas into the spaces between the refractory dams which delineate a molten metal pool by cooperating with water cooled rolls and the water cooled rolls. CONSTITUTION:The molten metal pool 3 is delineated of the upper peripheral surfaces of a pair of the water cooled rolls 1 and the side dams 2. The side dams 2 are disposed in such a state that the inside surfaces thereof contact with the side walls of the rolls 1 or have a slight space therefrom. The inert gas such as gaseous argon is blown via a gas ejection nozzle 6 to the spaces between the rolls 1 and the side dams 2. The inflow of the molten metal in the pool 3 into the spaces is prevented by the blowing of such inert gas. The need for manufacturing the side dams with high accuracy is thus eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for producing thin sheets directly from molten metal using twin rolls.

[Conventional technology]

Sheet metal is hot rolled into a cast metal material.

It has conventionally been manufactured by performing treatments such as cold rolling. However, when using this normal method, a large number of processes are required, such as a hot rolling process, a cold rolling process, and a heat treatment process performed between these processes, and accordingly, it is required to prepare various types of equipment. .

Therefore, recently, a method of directly cooling and solidifying molten metal into a thin plate has been proposed as a technique for easily manufacturing thin metal sheets without requiring multiple processes and various types of equipment. One of these methods is the twin roll method. A brief explanation of this twin roll system is as follows.

A pair of water-cooled rolls that rotate in opposite directions are arranged horizontally, and a sump part for storing molten metal is formed in the four parts defined by the pair of water-cooled rolls. The molten metal accommodated in this pool is cooled and solidified at the portion in contact with the water-cooled roll to form a solidified shell. As the rolls rotate, this solidified shell moves to a so-called roll gear, where a pair of rolls face each other at a position closest to each other. In the roll gap, the solidified shells formed on the surfaces of the water-cooled rolls are pressed together and integrated to form the desired thin metal sheet.

At this time, the water reservoir is formed by a side dam (Japanese Unexamined Patent Publication No. 59-1339
48), a nozzle-type dam placed on the peripheral surface of twin rolls (Japanese Patent Application No. 59-151387), etc. have been proposed. These side dams and nozzle-type dams are made of heat-resistant ceramics such as alumina, magnesia, and zirconia, and are formed with edges and grooves that follow the circumferential surface of twin rolls, or are made of heat-resistant ceramics such as alumina, magnesia and zirconia. Some are formed flat so that they can be pressed against the side wall.

[Problems to be Solved by the Invention] When defining a pool using such a side dam or nozzle type dam, it is particularly important to keep in mind that the refractory dam and twin roll circumferential surface It is a sticker with.

If this seal is incomplete, problems such as molten metal flowing out from the gap or sticking to the circumferential surface of the twin rolls will occur. Therefore, in order to perfect this seal, it was necessary to manufacture a refractory dam with high precision. However, even if a dam is manufactured with high precision, since it is used in contact with high-temperature molten metal, it is subject to severe melting and damage, and the initial sealing properties of the dam cannot be maintained for a long period of time. not.

Furthermore, as another method for achieving a complete seal, it has been proposed to press a refractory dam against the twin rolls with a constant pressure (Japanese Patent Application Laid-Open No. 57-9565 fl). However, in cases where the twin rolls are rotated at high speed to reduce the thickness of the slab, the sliding friction resistance between the refractory and the rolls increases when the refractory dam is pressed against the twin rolls. Therefore, wear and damage of the refractory dam are likely to occur. For this reason, the method of pressing the dam cannot maintain a good sealing state for a long period of time.

Additionally, the dam may be heated to prevent the formation of solidified shells on the sides of the sump. On the other hand, since it is necessary to actively generate a solidified shell on the surface of the twin rolls that come into contact with a dam equipped with such a heating mechanism, the surface of the twin rolls must be insulated from the dam and cooled. There is a need. For this reason, the method of pressing the dam requires providing a complicated heat insulating structure for the twin rolls themselves.

The present invention was devised to eliminate the drawbacks of such conventional side dams or nozzle type dams,
The purpose is to ensure a seal between the twin rolls and the dam without making any substantial design changes to the existing twin rolls and dams.

[Means for solving problems]

In order to achieve the above object, the method of the present invention pours molten metal into the upper space formed by a pair of water-cooled rolls that rotate in opposite directions at high speed, and cools and solidifies the molten metal while cooling and solidifying the molten metal. In a twin-roll thin plate production method in which the sheet is fed through a gap between water-cooled rolls and continuously cast into a thin sheet,
The method is characterized in that an inert gas is blown into a gap between the water-cooled roll and a refractory dam that cooperates with the water-cooled roll to define a pool of molten metal.

The apparatus of the present invention for carrying out the method includes a pair of water-cooled rolls that rotate at high speed in opposite directions, and a refractory dam that cooperates with the circumferential surface of the water-cooled rolls to define a pool. The present invention is characterized in that it is equipped with a gas blowout mechanism that blows inert gas into the gap between the surface of the water-cooled roll and the refractory dam.

〔Example〕

Next, features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 is a side sectional view showing an example in which the present invention is applied to a side dam, and FIG. 2 is a plan view thereof. In the figure, I represents a pair of water-cooled rolls arranged horizontally. This water-cooled roll 1 is made of a material with good thermal conductivity, such as copper, copper alloy, or iron, and has a water-cooled mechanism inside. The pair of water-cooled rolls 1 are opposed to each other with a gap (hereinafter referred to as roll gear) corresponding to the thickness of the target thin metal plate, as shown as d in FIG. The upper circumferential surfaces of the pair of water-cooled rolls 1 and the side dam 2 define a pool 3 for molten metal. This side dam 2 is made of ceramics with good heat resistance, such as alumina, magnesia, and zirconia. In the example shown in FIGS. 1 and 2, the side dam 2 is arranged on the side wall of the water-cooled roll 1. The molten metal poured into the molten metal sump 3 comes into contact with the water-cooled roll 1 and is cooled and solidified into a solidified shell 4. The solidified shells 4 formed on the circumferential surfaces of the respective water-cooled rolls move in the direction of the roll gear d as the rolls 1 rotate, and there they are integrally pressed against each other to form the thin metal plates 5.

At this time, the side dam 2 is arranged so that its inner surface is in contact with the side wall of the roll 1 or there is a slight gap therebetween, as shown in FIG. A gas jet nozzle 6 is installed in the gap between the roll l and the side dam 2.
Inert gas such as argon gas is blown in from the side through the tube. By blowing this inert gas, it is possible to prevent the molten metal in the sump 3 from flowing into the gap. In addition, if the side surface of the side dam 2 and the end surface of the roll 1 facing the side dam 2 are chamfered to create a gap for a gas flow path between them, it becomes easy to blow inert gas.

FIG. 3 shows an example in which the present invention is applied to a nozzle type dam. In this figure, parts opposite to those in FIGS. 1 and 2 are designated by the same reference numerals. In this embodiment, the hot water reservoir 3
is defined by a nozzle type dam 7. This nozzle type dam 7 is arranged so as to be in contact with the circumferential surface of the water-cooled roll 1 or to leave a slight gap therebetween. Even in this case, by blowing inert gas into the gap between the circumferential surface of the roll 10 and the nozzle-type dam 7 through the gas jet nozzle 6, it is possible to prevent molten metal from flowing into the gap.

In the above embodiment, the inert gas blowing nozzle 6
An example in which the dam is provided separately from the side dam 2 or the nozzle type dam 7 has been described. However, it goes without saying that the same effect can be obtained even if this inert gas blowing nozzle 6 is incorporated into the side dam 2 or the nozzle type dam 7.

Argon, helium, etc. are used as the inert gas blown into the gap between the water-cooled roll and the side dam or nozzle type dam. By blowing inert gas, the rolls in contact with the refractory side dam or nozzle dam are kept cool even if the dam is heated.

〔Effect of the invention〕

As explained above, according to the present invention, molten metal is prevented from flowing out from the gap between the water-cooled roll and the side dam or nozzle type dam by blowing inert gas. Therefore, it is no longer necessary to manufacture side dams or nozzle type dams with extremely high precision as in the past. For example, in the past, it was required to assemble a side dam or a nozzle type dam and a water-cooled roll with a spacing of about 0.25 mm, but according to the present invention, the spacing was widened to about 0.3 to 0.4 mm. Therefore, the design accuracy requirements for side dams or nozzle-type dams are relaxed.In addition, the side dams or nozzle-type dams can be designed to eliminate gaps between the side dams or nozzle-type dams and the water-cooled roll. There is no need to press the water-cooled roll.Furthermore, since the side dam or nozzle-type dam is not in contact with the water-cooled roll, when the side dam or nozzle-type dam is heated, the heat is transferred to the water-cooled roll, increasing its cooling capacity. In addition, the inert gas blown in this way bubbles the molten metal in the pool and prevents the formation of a solidified shell on the inner wall of the side dam or nozzle type dam. It also has the effect of

[Brief explanation of drawings]

FIG. 1 shows an embodiment in which the present invention is applied to a twin roll equipped with a side dam, FIG. 2 is a plan view thereof, and FIG. 3 is an embodiment in which the present invention is applied to a twin roll equipped with a nozzle type dam. An example is shown below. 1: Water cooling roll 2: Side dam 3: Hot water pool
4: Solidified shell 5: Metal thin plate 6: Gas jet nozzle 7: Nozzle type dam

Claims (1)

[Claims] 1. Molten metal is poured into the upper space formed by a pair of water-cooled rolls that rotate in opposite directions at high speed, and the molten metal is cooled and solidified while passing through the gap between the pair of water-cooled rolls. In a twin-roll thin plate manufacturing method in which the molten metal is continuously cast into a thin plate shape, an inert plate is placed in the gap between the water-cooled roll and a refractory dam that cooperates with the water-cooled roll to define a pool of molten metal. A thin plate continuous casting method using twin rolls that is characterized by blowing gas. 2. A pair of water-cooled rolls that rotate at high speed in opposite directions,
A refractory dam that cooperates with the circumferential surface of the water-cooled roll to define a pool, and a gas blowout mechanism that blows inert gas into the gap between the surface of the water-cooled roll and the refractory dam. A thin plate continuous casting device using twin rolls, characterized in that: