JPS6277158A - Device for controlling flow of molten metal for twin roll type continuous casting installation - Google Patents

Abstract

PURPOSE:To make the quality in a molten metal uniform and the quality of a thin metallic sheet uniform by disposing coils and cores for controlling the flow of the molten metal above a molten metal pool. CONSTITUTION:The cores 8 wound with the coils 7 are disposed above the molten metals pool and a control device 9 to pass AC or DC current to the coils 7 is provided. The AC current is supplied to the coils 7 to form a progressive magnetic field in the case of stirring the molten metal. On the other hand, the DC current is supplied to the coils 7 in the case of suppressing the flow of the molten metal. Linear type coils are used for the coils 7 and cores to generate the progressive or DC magnetic field.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to continuous casting equipment for producing thin metal sheets directly from molten metal by a twin-roll continuous casting method. This invention relates to a control device for stirring and controlling the flow of metal.

[Conventional technology]

Metal steel sheets have conventionally been manufactured by subjecting a cast metal material to treatments such as hot rolling and 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 many types of equipment. .

Therefore, recently, a method of directly cooling and solidifying molten metal into a thin sheet 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 a twin roll method using a pair of water-cooled rolling rolls. A brief explanation of this method is as follows.

That is, a molten metal dam is formed between a pair of water-cooled rolling rolls that are arranged parallel to each other and facing each other, molten metal is stored in the molten metal dam, and the molten metal is cooled by contacting the water-cooled rolling rolls to form a solidified shell. A thin metal sheet is continuously cast by forming a solidified shell and rolling the solidified shell using rainwater-cooled rolling rolls.

When the molten steel is solidified in the molten metal dam, the internal quality of the product can be significantly improved by stirring or braking the molten metal.

That is, by stirring the molten metal in the direction perpendicular to the casting direction in the molten metal dam, heat is removed from the molten steel in the molten metal dam, and by lowering the molten metal temperature, the equiaxed crystallinity of the slab can be improved. The internal quality of the slab can be improved.

In addition, by applying a DC magnetic field to the molten metal dam, the molten metal flow in the same direction as the casting direction, which is the injection flow during casting, is braked, thereby preventing the entrainment of impurities during casting. The internal quality of can be improved.

By controlling the flow of molten metal in this manner, the internal quality of the slab can be significantly improved.

Conventionally, as means for such flow control, there is an electromagnetic stirring device that utilizes electromagnetic action on molten metal. this is,
The molten metal is stirred by passing an alternating current, and the flow of the molten metal is suppressed by passing a direct current.

[Problem that the invention seeks to solve]

In conventional continuous casting equipment, this electromagnetic stirring device is installed next to the mold section, but when applying this to twin-roll type casting equipment, the conventional idea is to place the coil and core behind the rolls. I will do it. Therefore, the distance between the molten metal and the coil and core becomes long, and the efficiency of controlling the flow of the molten metal deteriorates.

The present invention was devised to solve these conventional problems, and an object of the present invention is to efficiently control the flow of molten metal even in twin-roll continuous casting equipment.

[Means and effects for solving the problems] The device of the present invention has the following features:
In order to achieve this purpose, molten metal is supplied to a pool formed above a pair of water-cooled rolls rotating in opposite directions, and the molten metal is passed through a roll gap between the pair of water-cooled rolls. In the twin-roll type continuous casting equipment for directly manufacturing thin metal sheets from molten metal, a coil and a core for controlling the flow of molten metal are arranged above the sump.

In the present invention, with the above-described configuration, the flow of molten metal can be efficiently controlled even in twin-roll continuous casting equipment.

〔Example〕

Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

FIG. 1 is a side view schematically showing a twin roll continuous casting equipment equipped with the flow control device of the present invention, and FIG. 2 is a front view.
In the figure, 1 and 2 are water-cooled rolls driven to rotate in opposite directions, 3.4 is a side dam for forming a pool above the water-cooled rolls 1 and 2, 5 is molten metal such as molten steel, and 6 is a sheet metal rolled from molten metal by passing it through the roll gap between water-cooled rolls 1 and 2.

In this embodiment, a core 8 with a coil 7 wound thereon is arranged above the pool, and a control device 9 is provided for passing an alternating current or direct current to the coil 7. energizes the coil 7 with an alternating current to form a traveling magnetic field.

On the other hand, when suppressing the flow of molten metal, a direct current is applied to the coil 7.

The coil 7 and the core 8 are linear coils, and generate a traveling magnetic field or a DC magnetic field.

The ball pitch in a linear coil is, for example, 270
~720 dragons, and the number of balls is 2 or 4.

The magnetomotive force of the coil is per core length l cn+,
The current is about 8,000 to 10,000 ampere, and the coil driving current can be direct current or alternating current in the range of 4 Hz to 60 Hz.

Further, the distance of the core from the molten metal surface is, for example, about 20 to 100+n, taking into consideration the strength of the magnetic field for the molten metal.

〔Effect of the invention〕

As described above, according to the present invention, by arranging the coil and core above the sump, flow control is performed from a close distance to the molten metal.

Therefore, even in the twin-roll type continuous casting equipment, it is possible to achieve the effect that the quality of the material in the molten metal and the metal sheet can be made homogeneous.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of the present invention, and FIG. 2 is a front view thereof. 1.2: Water-cooled roll 3, 4: Side dam 5: Molten metal 6: Metal thin plate 7: Coil 8: Core 9: Flow control device patent applicant Nippon Steel Corporation (and 1 other person) Agent Masu Kodo (and others) 2 people) Figure 1 Figure 2

Claims (1)

[Claims] 1. Molten metal is supplied to a pool formed above a pair of water-cooled rolls that rotate in opposite directions, and the molten metal is passed through a roll gap between the pair of water-cooled rolls. Twin roll type continuous casting equipment for manufacturing thin metal sheets directly from molten metal, characterized in that a coil and a core for controlling the flow of molten metal are arranged above the sump. Molten metal flow control device in equipment.