EP0345269A1

EP0345269A1 - Process and device for magnetically stirring metal bars

Info

Publication number: EP0345269A1
Application number: EP19880901018
Authority: EP
Inventors: Peter Stadler; Joachim Von Schnakenburg; Klaus-Dieter HÜBNER; Peter Auel; Klaus Albert Schweizer
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1987-01-23
Filing date: 1988-01-20
Publication date: 1989-12-13
Also published as: WO1988005353A1; BR8807327A; JPH02501903A; DE3702381A1; DE3702381C2; ES2006274A6

Abstract

Procédé permettant de ringarder magnétiquement une barre de métal (2) à produire par coulée continue, pendant la phase de solidification, à l'aide d'aimants permanents (6) disposés sur la barre et d'un courant continu (4) injecté dans cette dernière. A l'aide de moyens simples et pour de faibles coûts d'exploitation, il est généré dans la barre un ringardage avantageux notamment pour la coulée continue horizontale, sur la base du procédé connu consistant à influer par conduction sur une barre de coulée métallique. Ce ringardage permet d'appliquer au métal, de préférence le fer, l'acier et leurs alliages, une force qui agit sur les particules de matière en cours de solidification, notamment des globulites, dans le sens circonférentiel, les dissociant de manière aussi homogène que possible. La barre est exposée, sur toute sa circonférence, à l'action des champs magnétiques des aimants permanents (6) de telle manière que lesdits champs magnétiques soient injectés radialement et avec une séquence polaire alternant dans le sens longitudinal.Method for magnetically coring a metal bar (2) to be produced by continuous casting, during the solidification phase, using permanent magnets (6) placed on the bar and a direct current (4) injected into the latter. With the aid of simple means and for low operating costs, an advantageous ringing is generated in the bar, in particular for horizontal continuous casting, on the basis of the known method of influencing by conduction on a metal casting bar. This ringing makes it possible to apply to the metal, preferably iron, steel and their alloys, a force which acts on the particles of material in the course of solidification, in particular globulites, in the circumferential direction, dissociating them in a so homogeneous way as possible. The bar is exposed, over its entire circumference, to the action of the magnetic fields of the permanent magnets (6) so that said magnetic fields are injected radially and with a polar sequence alternating in the longitudinal direction.

Description

Ver drive and Vorr i rect the magnet i rule stirring ei nes metal ^¬ s Trang and Vorr i chtung_zur_Durch führung_des_Ver drive

1 -

It is known to produce flow movements in metallic melts which are processed in the continuous casting process with the aid of magnetic stirrers. On the one hand, this serves to impart a desired flow direction to the melt or to prevent segregations during the solidification process, by which the solidification structure of the metal could be adversely affected. Usually, the liquid metal is brought under the influence of an electrical rotating field during casting and is set into a circular movement by the resulting induction currents, which runs in the same direction as the rotating field.

It is also known to generate a desired movement by means of a permanent magnet, the poles of which are located on opposite sides of the casting strand, and by feeding DC voltage into the casting strand.

The object of the invention is, based on the known method of conductive influencing of a metallic casting strand with simple means and low operating costs, to produce a stirring movement in the strand which is particularly advantageous for horizontal continuous casting, with the aid of which the metal, preferably iron and steel and their alloys, can be produced a force is exerted which acts on the solidifying material particles, in particular globolites, in the circumferential direction and segregates them as homogeneously as possible.

To achieve this object, the method defined in claim 1 is proposed.

The device specified in claims 2 to 5 for carrying out the method according to the invention is characterized by special simplicity, reliable operation and low operating costs.

The invention is explained in more detail with reference to the exemplary embodiment shown schematically in the drawing.

It shows:

FIG. 1 shows a horizontal continuous casting installation in a schematic side view,

Figure 2 shows the arrangement of the permanent magnets in an enlarged view

Figure 3 different embodiments for the iron rings to be arranged between the permanent magnets.

The horizontal continuous casting plant for steel strands shown schematically in FIG. 1 usually consists of a feed container 8 filled with melt, to which the mold 9, in which the strand is formed, adjoins. The strand 2, which begins to solidify in the mold from the outside, is passed through a permanent magnet system arrangement 3 while it still has a liquid or pasty inner region. The further movement of the solidified strand 2 takes place with the aid of a conventional drawing machine 10. In the direction of movement in front of and behind the permanent magnet system 3, a direct voltage generated in the arrangement 1 is applied to the strand 2 at 4. In cooperation with the permanent magnets, there is a stirring movement which causes the globolites to separate or to equalize the strand by preventing segregation. As can be seen from FIG. 2, the permanent magnet system consists of the magnets concentrically surrounding the circular strand 2, which are magnetized axially, in such a way that the north pole is located on one and the south pole on the other annular end face of the permanent magnets . Two successive magnets of the arrangement are oriented opposite each other. Between the adjacent permanent magnets 6 and also on their end faces, iron rings or disks 5 are provided, which, as explained in FIG. 3, are designed by radially extending cross-sectional conditions such that they are caused by the circumferential magnetic field are not magnetically saturated by the current flowing in strand 2. The magnetic resistance in the iron rings or disks 5 can also be increased by appropriate air gaps.

Both the permanent magnets and the iron rings or disks are expediently divided into segments along radially running surfaces.

Claims

Method for magnetically stirring a metal strand to be produced in the continuous casting process during the solidification phase with the aid of permanent magnets arranged on the strand and direct current fed into the strand,

characterized,

that the strand is exposed over its entire circumference to the action of the magnetic fields of the permanent magnets, in such a way that the magnetic fields are fed in radially and with an alternating pole sequence in the longitudinal direction.

2. Device for performing the method according to claim 1, characterized in that the permanent magnets (6) as the casting strand (2) in the circumferential direction surrounding hollow bodies and are magnetized in the axial direction, with adjacent permanent magnets (6) having alternating polarity, and that between two adjacent permanent magnets (6) and on the end faces of the permanent magnets located at the ends of the arrangement, a magnetically non-saturable iron ring (5) is arranged, which is not saturated by the magnetic field generated by the strand current in the circumferential direction.

3. Apparatus according to claim 2, characterized in that the iron ring (5) has radial cross-sectional reductions (11a to 11h) which increase its magnetic resistance.

4. Apparatus according to claim 2 and / or 3, characterized in that the permanent magnets (6) and / or the iron rings (5) are divided into segments.

5. Device according to claims 2 to 4, characterized in that between the casting strand (2) and the inner surface of the permanent magnets (6) or the iron rings (5) cooling channels (7) are arranged.

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