Device for continous or semi-continous casting of metal material

Abstract

The present invention relates to a device for continuous or semi-continuous casting of a metal material. The device comprises a first arrangement comprising a coil (7) having an extension around the casting mould (2) in an area, which is arranged to comprise molten metal material. The coil (7) is arranged to be fed with alternating current such that a varying magnetic field is generated and is applied to the molten metal material in the casting mould (2). The device also comprises a second arrangement comprising at least two magnetic poles (8), which are provided at opposite sides of the casting mould (2). The poles (8) are arranged to supply a static or periodic low-frequency magnetic field to the molten metal material in the casting area. The poles (8) comprise at least a portion (11) which comprises a plurality of material layers which are electrically insulated from each other.

Description

BACKGROUND OF THE INVENTION AND PRIOR ART[0001] The present invention relates to a device for continuous or semi-continuous casting of a metal material, wherein the device comprises a casting mould which allows casting of a metal material to a desired shape, means for supplying a molten metal material to the casting mould, a first arrangement comprising a coil having an extension around the casting mould in a moulding area arranged to comprise molten metal material and which coil is arranged to be fed with an alternating current in such a way that a varying magnetic field is generated and is applied to the molten metal material in the casting mould and a second arrangement comprising at least two magnetic poles which are provided at opposite sides of the casting mould and which poles are arranged to supply a static or periodic low-frequency magnetic field to the molten metal material in the casting mould.[0002] The metal material used at such a casting process may be a pure metal or...

AI Technical Summary

Benefits of technology

[0007] According to another preferred embodiment of the present invention, said portion of the pole comprises a part of the pole, which is located nearest the coil of the first arrangement. Generally, the poles are provided on the outside of the coil, which generates the varying magnetic field. That part of the poles, which is located nearest the coil, is subjected to the heaviest varying magnetic field for that reason and consequently ought to be laminated first of all. The thickness of the laminated layers may be elected with regard to the so-called depth of penetration of the magnetic field in the pole material. The depth of penetration may be calculated with a knowledge of the frequency of the magnetic field and the resistivity and permeability of the pole material. Advantageously, each of said layers comprises a plate shaped element having two substantially plane lateral surfaces which have an extension in a plane substantially perpendicular to the direction of current in the most closely located part of the coil. Thus, such an orientation of the layers is obtained that a minimal field constriction is obtained by the varying magnetic field and the influence on the varying magnetic field by the pole becomes substantially negligible.

[0008] According to another preferred embodiment of the present invention, the coil of the first arrangement and at least one of the poles of the second arrangement are provided in contact with each other. Hereby, a compact device is obtained. At the same time, a relatively small air-gap between the end surfaces of the poles provided towards each other is obtained. A small air-gap between the end surfaces of the poles results in that a less supply of electric energy is required for establishing a required static magnetic field acting on the melt in the casting mould. In order to reduce the air-gap further between the end surfaces of the poles directed to each other, one pole may at least comprise a recess which is arranged to receive said coil. Thus, a further compact unit is obtained. Advantageously, the coil and the poles constitute here an integrated part.

Problems solved by technology

Hereby the risk decreases that harmful inclusions arise in the finished cast strand in form of, for example, slag and gases.

However, the existence of the solid poles of the magnetic material of the electromagnetic brake in immediate vicinity of the coil fed with alternating current results in an influence of the magnitude and extension of the varying magnetic field.

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