DE2944760A1 - DEVICE FOR STIRRING METAL MELT IN CONTINUOUS CASTING MILLS - Google Patents

Abstract

1. Apparatus for stirring metal melts in continuous casting plants during the solidification process by means of a constant magnetic field which passes through the string (2), which is guided between rollers (3), at right angles to the direction of movement of the string, and which also cuts a constant current which is passed through the string (1) at right angles to the direction of movement thereof and to the constant field, in which the yoke (6) of an electromagnet (4) which produces the constant field, is arranged on the wide side of the string outside the guide rollers (3), and the magnetic poles are each provided with a pole shoe (9) embracing at least one of the guide rollers (3), whilst on the other wide side of the string (1), there is arranged a return armature (5) having correspondingly designed poles (11) and in which, in order to supply the constant current, contact brushes or contact rolls, which can be directly pressed against the narrow sides of the surface of the string, are provided, characterised in that on the yoke (6) of the electromagnet (4), there are arranged two magnetic systems, the field coils (7) of which produce oppositely-directed magnetic fields.

Description

29U760

SIEMENS AKTIENGESELLSCHAFT Our mark Berlin and Munich VPA 79 P 3 2 0 8 FRG

Device for stirring :) of metallic melts in continuous casting plants

b a. (AEHBel-dwag- 36 The invention relates to a device for stirring

Clay metallic melts in continuous casters during of the solidification process by means of a magnetic Constant field that penetrates the strand guided between rollers and perpendicular to its direction of movement which intersects a direct current conducted through the strand also perpendicular to the direction of movement, wherein the yoke of an electromagnet generating the constant field on a broad side of the strand outside the guide rollers is arranged and the magnetic poles are each equipped with a pole piece encompassing at least one of the guide rollers, while on the the other broad side of the strand is a return anchor

Hk 2 Tue / November 2nd, 1979

130019/0602

- * VPA 79 P 3 2 0 8 BRD

is arranged with corresponding tuppebild + en poles and for supplying cUjs direct current directly to the Strand surface «^ printable contact brushes or Contact rollers are provided.

In this in the main notice P 29 18 700.6 described The device is created from the electromagnetically generated flow of the still liquid melt in Inside the strand and from the flow based on the convection a main trough field, which is asymmetrical runs to the strand axis. This results in asymmetries in the strand structure.

It can also be symmetrical to the axis of the magnet assembly running chisel parts which are connected to one another in a magnetically conductive manner; are, for example, the carriers the leadership roles that favor the formation of strong stray fields.

The invention is based on the object of the flow field to symmetrize in relation to the strand axis and to eliminate the disruptive influence of iron parts.

According to the invention, this object is achieved in that two magnet systems on the yoke of the electromagnet are arranged, whose excitation windings generate oppositely directed magnetic fields.

The opposing magnetic fields create a main flow in the direction of and symmetrical to the Longitudinal axis of the strand. Iron parts that run symmetrically to the longitudinal axis of the strand are magnetically attached same potential, so that a compensating magnetic flux does not occur.

13 0019/0602

29U76Q

VPA 79 P 3 208 FRG

Execution example shown on the basis of a t η of the drawing! π we · * the invention is explained in more detail below.

Figure 1 shows et reu Horizon ta] section through one

Strand 1 in the area of a continuous caster in which the core 2 of the strand supported by Füh runge ro 11 et) 3 on both broad sides is still liquid. In this area, a 4-bit electromagnet is arranged in a yoke armature 5. The yoke 6 of the electromagnet carries two oppositely wound excitation coils 7 which generate oppositely directed magnetic fields. The two adjacent poles of the same name of the two magnet systems formed in this way are united in a common SoJinukel B tpi.

As can be seen from FIG. P, this leg branches into two follower shoes 9, the mutual spacing of which is adapted to the diameter of at least one of the guide rollers and which each encompass at least one of the guide rollers 3. In the same way, the middle leg 10 of the yoke armature runs into two pole shoes 11 »» us. The support legs 12, 13 of the electromagnet 4 and the corresponding legs 14, 15 of the yoke armature 5, however, are each equipped with only one pole piece.

The contact rollers or brushes to be arranged on the narrow sides of the strand for supplying the direct current, which produces the stirring effect in connection with the magnetic fields are not shown in FIG. The opposing magnetic fields of the electromagnet form in the still liquid core of the strand from partial flows that are in the area

; 3001 9/0602

S. 294Λ7Β0

- y- VPA 79 P 3208 BRD

dee Mittelechenkels 8 to one example the plus signs indicated, emerging from the drawing plane upwards and indicated by the minus signs, assemble the plane of the drawing from above penetrating the main flow. This mainstream accordingly runs symmetrically to the longitudinal axis of the strand. By branching the middle pole leg 8 and of the corresponding leg 10 of the return link anchor in Every two pole pieces, the magnetic field is applied to the bulge of the streamlines in the middle of the strand customized. This significantly improves the efficiency of the stirring device.

The guide rollers 3 lying in the area of influence of the electromagnetic system are expediently made of non-magnetic material Material made so that the magnetic field lines emanating from the pole pieces do not affect the strand can enforce. The symmetrically arranged to the longitudinal axis of the strand, over the main frame Interconnected carriers 16 of the guide rollers are due to the oppositely directed magnetic fields magnetically at the same potential. This means that there is no additional leakage flux.

The use of an electromagnet with two coils wound in opposite directions to generate opposite directions Directed magnetic fields also offers the advantage that the device without changes to manufacture of slabs of different dimensions can be used.

3 claims
2 figures

1 30019/0602

Claims (3)

294476Q VPA 79 ρ 3 208 BRD claims 1. Device for stirring metallic melts in continuous casting plants during the solidification lake by means of a constant magnetic field, which moves the strand guided between rollers perpendicular to its direction of movement interspersed and the one passed through the strand also perpendicular to the direction of movement Direct current cuts, with the yoke of an electromagnet generating the direct field on one broad side of the strand arranged outside the guide rollers and each of the magnetic poles is equipped with a pole piece that encompasses at least one of the guide rollers are, while on the other broad side of the strand a return anchor with appropriately trained Poles are arranged and can be pressed directly onto the strand surface for supplying the direct current Contact brushes or contact rollers are provided, according to patent (application P 29 18 700.6), characterized in that there are two magnet systems on the yoke (6) of the electromagnet (4-) are arranged, the excitation windings (7) generate oppositely directed magnetic fields. 2. Device according to claim 1, characterized in that the adjacent, magnetic poles of the same name of the two systems are combined to form a pole leg (8). 3. Device according to claim 2, characterized in that the follower leg (8) and the middle leg (10) of the yoke armature (5) run out in two pole shoes (9 or 11) and the distance between the pole pieces to the diameter at least one of the guide rollers (3) is adapted. 1 30019/0602