JPS6021169A - Nozzle for continuous casting - Google Patents

Abstract

PURPOSE:To permit easy pouring and to obtain a thin metallic plate which contains less nonmetallic inclusions with a casting nozzle of a horizontal synchronous continuous casting device by specifying the inclination thereof and the sectional area for pouring and providing a receiving port and an inert gas feed pipe. CONSTITUTION:The casting direction of a continuous casting nozzle 1 is set within horizontal + or -30 deg. and the molten metal 16 in the nozzle 1 is supplied through a pouring port to the space between endless belts 2 and 2', thereby casting a thin plate. The sectional area (the distance between points 5 and 6X the inside measure width of the nozzle) of the pouring port of the nozzle 1 is made to >=2 times the sectional area (the distance between points 7 and 7'X the width of a billet) of the billet. A side dam is formed on an inclined front wall surface 103, the lower horizontal parts of side walls 104, 104' and a base 101. A receiving port 13 which accepts a pouring nozzle 12 and a gas feed pipe 14 which introduces an inert gas are provided to a ceiling surface 102 to form a molten metal well 16 having a free surface 17 so that nonmetallic inclusions 19 are separated and floated therein.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle for continuous thin sheet casting, which allows easy pouring of metal and enables casting of thin metal sheets with fewer inclusions.

A device that continuously casts thin plates (several mo+) directly from molten metal using a mold formed by a pair of synchronously moving members is a twin-roll device in which a pair of rolls serving as the mold rotate in synchronization with the movement of the slab. Type continuous casting machines, twin belt type continuous casting machines in which a pair of endless belts as molds or similar running synchronously are well known. These are roughly divided into vertical types, in which the casting direction at the initial stage of solidification is approximately vertical, and horizontal types, in which the casting direction is approximately horizontal. The vertical type tends to form a large pool in the pouring part of the continuous caster, but the molten metal tends to be large, and leakage is likely to occur from the contact surface between the casting nozzle feed port and the mold. Furthermore, the height of the continuous casting machine increases, which not only increases construction costs but also impairs operability.

On the other hand, the haze-cut type continuous casting machine (for this equipment,
Iron and 5teel Engineer magazine,
June, 19 [A review article is published in 1B. Most of the horizontal continuous casting machines represented by ) are of the twin-belt type, but there are open nozzle and closed nozzle types. In this case, the above-mentioned problems are rare, but in the case of a closed nozzle, the cross-sectional area of the casting nozzle pouring port is small, causing a drop in the temperature of the molten metal within the casting nozzle, and nozzle blockage due to solidification of the molten metal. Pouring is extremely difficult. In the case of an open nozzle, pouring is relatively easy, but since the molten metal surface is in contact with the upper endless belt, non-metallic inclusions floating on the molten metal surface are likely to be trapped on the upper surface of the slab while the belt is running. There was a problem that water wrinkles were likely to occur due to fluctuations in the hot water level. This difficulty associated with open nozzles is significant when the casting direction is ±30° horizontal.

It is an object of the present invention to solve the above-mentioned problems and provide a casting nozzle in a continuous thin plate casting machine that facilitates pouring and makes it possible to produce thin plates with fewer nonmetallic inclusions and wrinkles. .

According to the present invention, there is provided a continuous casting nozzle for a horizontal synchronous continuous casting apparatus in which the casting direction is within ±30° horizontally, and the cross-sectional area of the pouring port of the casting nozzle is equal to the cross-sectional area of the slab to be cast. The pouring spout can be installed in contact with or close to a pair of molds that move in synchronization with the slab, which are placed above and below the pouring spout, and the hot water is supplied to the ceiling. It is equipped with a molten metal inlet into which a nozzle can be inserted and an inert gas supply pipe, whose side wall extends so as to come into contact with the synchronously moving mold, and is connected to a fixed side dam. A casting nozzle for continuous casting is provided, which is characterized in that it can secure a head space in which a surface can be formed.

The casting nozzle of the present invention can be applied to both a twin endless belt type continuous casting machine and a twin roll type continuous casting machine.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

Figure i1 shows the concept of a continuous casting apparatus using the casting nozzle of the present invention. The casting nozzle of the present invention is shown in perspective view in FIG.

The casting nozzle l of the invention is made of a refractory material, preferably L±, a so-called new ceramic material, and is generally WJ
It has the shape of an open-sided box, with the open front forming the spout. In the embodiment shown in FIG. 1.2, the bottom surface 101 is shorter in the front-rear direction than the ceiling surface 102, and only the upper half of the di+ surface is a front wall surface 103 inclined like an eave.

The front edges of the side walls 104, 104' descend diagonally from the ceiling in a straight line, and at a distance from the base approximately equal to the thickness of the sheet metal to be cast, transition with a certain curvature into a straight line parallel to the base, and then It extends to the starting point of 7.7° and connects to a side dam (not shown).

Support roll 201', tension roll 202', W
An endless belt 2° supported and driven by a dynamic TFF-rule 203'' is disposed in close contact with the bottom surface of the nozzle and the extension of the side wall to form the bottom surface of the mold.Of course, the bottom surface of the endless belt 2° is A cooling box is placed,
Then, high-pressure, high-flow cooling water is ejected to cool the belt and push against the side walls and side dams of the casting nozzle to prevent any leakage.

On the upper side, a support roll 201, a tension roll 202,
An endless belt 2 supported and driven by a drive roll 203 is placed in close contact with the extensions of the front wall 103 and side walls 104, 104' to form the upper surface of the mold. Of course, like the lower belt, a cooling box (not shown) is provided on the inside of the endless belt, and high-pressure, high-flow cooling water is jetted from this box to press the belt against the mold side wall and side thumb and cool it. It goes without saying that the lower surface of the cooling box has a shape that follows the side wall and side dam.

The cross-sectional area of the pouring port of the nozzle (distance between points 5 and 6 x inner diameter of the nozzle 1]) is at least twice the cross-sectional area of the slab (distance between points 7.7° x width of the slab). be. As mentioned earlier, if the cross-sectional area of the pouring port of the nozzle is small, nozzle clogging is likely to occur, but according to experiments by the present inventors, if L is approximately twice the cross-sectional area of the slab to be cast, It has been found that nozzle clogging can be prevented.

The ceiling surface 102 of the nozzle is provided with a hot water inlet 13 for receiving the hot water supply nozzle 12 of the tundish and a gas supply pipe 14 for introducing an inert gas such as At.

Molten metal is fed from the tundish by a feed nozzle 12 to form a sump 16 having a free surface 17 within the casting nozzle. The free surface 17 is detected by a hot water level detector 18 and controlled so that the hot water level is always above the upper edge 5 of the pouring spout. If necessary, pressure may be applied with an inert gas.

By forming the casting nozzle in this manner, the molten metal is temporarily stored before being cast, so that non-metallic inclusions and other impurities 18 are not separated and floated up during that time and rolled into the L side of the mold.

When the casting nozzle of the present invention is applied to a twin endless belt type continuous casting machine, the geometrical conditions of contact between the spout and the belt are not limited to the above-mentioned embodiments.

The front wall may be cylindrically curved.

The casting nozzle of the present invention can also be applied to a twin-roll continuous casting machine. Its implementation is shown in FIG.

The casting nozzle shown in FIG. 3 is generally similar to that shown in FIG. 2, except that the front wall 103 consists of a vertical portion 103a and a horizontal portion 103b, and the bottom surface is connected to the leading edge of the horizontal portion of the front wall. It extends to the same position. 1 pair of rolls 2
8.28' are located at the horizontal portion of the front wall of the casting nozzle and at the front edge of the bottom surface to form a mold. The side wall of the casting nozzle draws an arc that is the same as the circumference of the roll, and the closest point of the roll is 8.
．． It extends to 8°. Of course, the roll is a drum roll and is internally cooled. It is obvious that this embodiment also achieves the same effects as described above.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the concept of one embodiment of a continuous casting machine including a casting nozzle of the present invention. FIG. 2 is a perspective view of the casting nozzle of the present invention shown in FIG. 1. FIG. 3 is a perspective view 1Δ of a casting nozzle according to another embodiment of the present invention.
It is. In these figures, 2.2', , endless belt 3.3', , roll 161. Casting nozzle tS, Molten metal 12, Hot water supply nozzle 14, Inert gas supply pipe 18', Molten metal level detection device Patent applicant Nisshin Steel Co., Ltd. Agent Patent attorney Masahiro Matsui (1 other person) #/Figure/Z Pit 3 figure

Claims (1)

[Scope of Claims] 1. A continuous casting nozzle for a horizontal synchronous continuous casting device in which the casting direction is within ±30° horizontally, where the cross-sectional area of the pouring port of the casting nozzle The cross-sectional area of the slab is at least twice the cross-sectional area of the slab, and the pouring spout can be installed in contact with or close to a pair of molds that move in synchronization with the slab, which are placed in one pouring spout, and the ceiling portion thereof It is equipped with a spout into which a hot water supply nozzle can be inserted and an inert gas supply pipe, the side wall of which extends so as to come into contact with the synchronously moving mold and is connected to a fixed side tom, and the molten metal is freely placed at a position higher than the pouring spout. A casting nozzle for continuous casting, characterized in that it can secure a head space in which a surface can be formed. 2. A casting nozzle according to claim 1, characterized in that its pouring port is configured to come into contact with two endless belts running synchronously. 3. The casting nozzle according to claim 1, characterized in that the pouring spout is configured to come into contact with rotating twin rolls. 4. Claims 1 to 3J! 4. The casting nozzle according to any one of Items 4 to 4, characterized in that the casting nozzle is equipped with a device for detecting the molten metal level within the casting nozzle.