JPH0299246A - Twin belt type continuous casting machine - Google Patents

Abstract

PURPOSE:To improve controllability of flow rate of molten metal by extending lower end parts of linear motors facing to a flat nozzle connected with bottom part of a tundish from upper end of upstream side rolls to the lower part. CONSTITUTION:The flat nozzle 1 is extended from the bottom part of the tundish to the inner part of the molten metal M in a mold 3. The mold 3 has one pair of mutually facing endless casting belts 7 wound on the upstream side rolls 4 and one pair of facing shiftable short sides 8 arranged at right and left of the width direction. The side faces of the shiftable short sides 8 are brought into contact with gap between the belt faces of the belts 7 to form the flat mold 3. The linear motors 11 are arranged so as to face to the flat nozzle 1, and lower end parts 13 of iron cores 12 are inserted into gaps between rolls 4 and the flat nozzle 1. Electric current is conducted to coils 15 through an inverter. As electromagnetic force reaches to the molten metal M in the flat nozzle 1, the controllability of the flow rate is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a twin-belt continuous casting machine that continuously casts flat slabs.

[Prior Art] A twin-belt continuous casting machine is one of the devices for casting slabs having a rectangular or flat cross-sectional shape.

This twin-belt continuous casting machine includes a tundish, a flat nozzle connected to the bottom of the tundish, a pair of linear motors facing the wide surfaces of both of the flat nozzles, and a flat mold. . The flat mold has a pair of opposing endless casting belts wound around at least an upstream roll and a downstream roll, and a pair of opposing short side molds, and the side surfaces of the short side molds are arranged between the belt surfaces. A mold is formed so that they are in contact with each other. Then, while rotating the casting belt in the slab drawing direction, molten metal is injected into the mold to continuously cast slabs having a rectangular or flat cross-sectional shape. Such twin-belt continuous casting machines are disclosed in, for example, Japanese Patent Application Laid-open Nos. 166145-1982 and 1855-1983.
It is disclosed in Publication No. 54 and others.

According to the twin-belt continuous casting machine, it is possible to directly produce a flat slab having a thickness of several ff1 m to several tens of mm, which is close to the final shape, from molten metal such as molten steel.

Here, the flat molds and slabs refer to elongated molds with circular, oval, or square sides. Therefore, multi-step rolling processes such as rough rolling and intermediate rolling can be omitted in the production of metal ribbons, thereby simplifying the process and equipment. Furthermore, since there is no need for a heating process for the material between each process, an energy saving effect can also be expected.

The molten metal injection rate varies depending on the molten metal head within the tundish. Also, if the slab is flat, casting is performed at a high casting speed and therefore at a high molten metal injection rate. Therefore, as casting progresses, the molten metal head in the tundish and the molten metal injection rate change rapidly, and the molten metal surface level in the mold fluctuates. On the other hand, the molten metal surface level must be within a certain range in order to start cooling the molten metal from a proper position in the mold or to prevent the molten metal from overflowing from the mold. For this purpose, it is necessary to control the flow rate of molten metal.

When molten metal is supplied from the tundish to the mold through the nozzle, the flow rate of the molten metal is controlled by a linear motor placed close to the nozzle (acting as an electromagnetic pump since the carrier is a conductive fluid). It is known. For example, see JP-A No. 61-140351, "Metal J" (15th October 1968 issue, pp. 2-9), "Ashyou Denki" (Vol. 35, Vol. 1, No. 135, pp. 186-194).

[Problems to be Solved by the Invention] In order to control the flow rate of molten metal using a linear motor, the linear motor must have a plurality of magnetic poles along the flow direction of the molten metal in order to apply the necessary electromagnetic force to the molten metal. It requires a certain length because it will be placed. Therefore, the flat nozzle must also be made long according to the length of the linear motor.

By the way, in a conventional twin-belt continuous casting machine equipped with a linear motor, the linear motor 17 has a rectangular shape as shown in FIG. It was located. Therefore, the lower portion of the flat nozzle 1 that is not affected by the electromagnetic force of the linear motor 17 becomes longer, and the flat nozzle 1 becomes longer by that amount. Since the flat nozzle 1 is flat,
It is difficult to manufacture a long flat nozzle 1, and as the length increases, the manufacturing cost increases rapidly.

Further, in order to improve the controllability of the flow rate of molten metal, it is desirable that the flat nozzle 1 is short and that the electromagnetic force of the linear motor I7 acts as close as possible to the molten metal surface m in the mold.

Therefore, the present invention aims to provide a twin-belt continuous casting machine in which the flat nozzle can be shortened and the flow rate of molten metal can be easily controlled by a linear motor.

[Means for Solving the Problems] The twin-belt continuous casting machine of the present invention includes a tanditsh, a flat nozzle connected to the bottom of the tanditsh, and a pair of linear motors each facing the wide side of both flat nozzles. and a flat mold. The flat nozzle may be connected to the tundish via a sliding nozzle. The flat mold has a pair of opposing endless casting belts wound around at least an upstream roll and a downstream roll, and a pair of opposing short side molds, and the side surfaces of the short side molds are arranged between the belt surfaces. A mold is formed so that they are in contact with each other. The lower end of the linear motor extends below the upper end of the upstream roll.

It is desirable that the lower end of the linear motor extends as far downward as possible without interfering with the flat nozzle and the upstream roll. For this purpose, the lower end of the linear motor may be cut out along the circumferential surface of the upstream roll.

In this case, the cutout is made in an arc shape, a straight line shape, or a polygonal shape. Of course, linear motors have windings wound around the iron core almost to the bottom end.

[Function] The linear motor also applies electromagnetic force to the molten metal in the flat nozzle at the lower end that is inserted between the flat nozzle and the upstream roll. Therefore, the flat nozzle can be shortened by the length that the linear motor enters. Furthermore, the electromagnetic force of the linear motor acts on the molten metal in the flat nozzle up to the surface of the molten metal in the mold.

[Example Figures 1 and 2 show an example of this invention.
FIG. 1 is a schematic side view of the vicinity of a mold of a continuous casting machine, and FIG. 2 is an enlarged view of the lower end of the linear motor shown in FIG. 1.

As shown in FIG. 1, a flat nozzle 1 extends from the bottom of a tundish (not shown) into molten metal M in a mold 3.

The mold 3 consists of a pair of opposing endless casting belts 7 wrapped around an upstream roll 4 and a downstream roll (not shown).
and a pair of opposing movable short sides 8 arranged on the left and right in the width direction. A flat mold 3 is formed such that the side surface of the moving short side 8 is in contact with the belt surfaces.

A pair of linear motors 11 are arranged so as to face both wide surfaces of the flat nozzle 1, respectively. The iron core 12 of the linear motor 11 has a flat plate shape and has a width that covers the opening of the flat nozzle 1 in the long side direction of the mold. A plurality of grooves 14 are cut into the iron core 12 and extend horizontally on a surface facing the wide surface of the flat nozzle 1. 6 grooves 1
A winding 15 is wound around the nozzle 4 so that a traveling magnetic field is generated in the vertical direction of the nozzle when a current is applied. Also, iron core 1
The lower end portion 13 of 2 is cut out in an arc shape along the circumferential surface of the upstream roll 4, and is inserted between the flat nozzle 1 and the upstream roll 4. And the lower end 1
3 is also provided with a winding 15. A power supply is connected to the winding 15 via an inverter, and the inverter is connected to the control device (
(none of which are shown) controls the output.

The specifications of the twin-belt continuous casting machine equipped with the linear motor configured as described above are as follows.

Mold (slab) cross-sectional dimensions: long side 600 x short side 50 mm
Nozzle outer diameter dimensions: width 300 x thickness 40 ++ Number of on nozzles = 1 Nozzle immersion depth: 50 n+m Casting speed: same m/min Further, the specifications of the linear motor are as follows.

Outer diameter dimensions, height 670 x width 300 x thickness 2] Omm Winding groove dimensions: depth 80 x width 10 x pitch 20 mm Lower end adult length L: 200 mm Rating: 120
Hz, to 2800 kV Ball pitch: 300m
m Number of poles = 2 By adopting the above linear motor, the length of the flat nozzle was able to be shortened by 200) compared to the conventional one. Further, as a result of casting with the above-mentioned casting machine, the molten metal surface level could be maintained almost constant.

[Effects of the Invention] In this invention, since the linear motor is inserted between the flat nozzle and the upstream roll, the flat nozzle can be made shorter by that much compared to the conventional one.

Further, since electromagnetic force acts on the molten metal in the flat nozzle also at the lower end of the linear motor, the electromagnetic force reaches close to the molten metal surface. Therefore, the controllability of the flow rate of molten metal by the linear motor is improved.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 2 is a schematic side view of the vicinity of a mold of a continuous casting machine, FIG. 2 is an enlarged view of the lower end of the linear motor 11 shown in FIG. 1, and FIG. FIG. 2 is a schematic side view of the vicinity of a mold of a conventional continuous casting machine. 1...Flat nozzle, 3...Mold, 4...Upstream roll, 5...Roll upper end, 7...Casting belt,
8...Short side mold, 11-...Linear motor, 12...
・Iron core, 13...lower end, 14...groove, 15...
Winding wire, 17... Linear motor, 18... Lower end of linear motor, M... Molten metal, m... Molten metal surface.

Claims (1)

[Claims] 1. A flat mold comprising a tundish, a flat nozzle connected to the bottom of the tundish, a pair of linear motors facing the wide surfaces of both the flat nozzles, and a flat mold. has a pair of opposing endless casting belts wound around at least an upstream roll and a downstream roll, and a pair of opposing short-side molds, such that the sides of the short-side molds are in contact between the belt surfaces. 1. A twin-belt continuous casting machine in which a mold is formed in a twin-belt type continuous casting machine, characterized in that a lower end of the linear motor extends below the upper end of the upstream roll. 2. The twin-belt continuous casting machine according to claim 1, wherein the lower end of the linear motor has a notched shape along the circumferential surface of the upstream roll.