Levitation melting method using movable induction units

Abstract

The invention relates to a levitation melting process and a device for producing castings with movable induction units. In this process, induction units are used in which the opposite ferrite poles with the induction coils are movable and move in opposite directions. In this way, the induction units for melting the batches can be arranged close together in order to increase the efficiency of the induced magnetic field. When casting the molten batch, the induced magnetic field is reduced by increasing the distance between the ferrite poles with the induction coils, thus preventing the melt from touching the ferrite poles or the induction coils.

Claims

1. A method for producing cast bodies from an electrically conductive material by a levitation melting method, wherein alternating electromagnetic fields levitate a batch, the alternating electromagnetic fields being generated with at least one pair of opposing induction coils with a core of a ferromagnetic material, wherein the induction coils with their cores are movably arranged in each pair relative to each other and move between a small distance melting position and a wide distance casting position, comprising: moving the pairs of induction coils with their cores to the smelting position at a small distance; introducing a batch of a starting material into a sphere of influence of at least one alternating electromagnetic field so that the batch is kept in a levitating state; melting the batch; positioning a casting mold in a filling area below the levitating batch; casting the entire batch into the casting mold by moving the induction coils with their cores in at least one pair from the melting position at a small distance to the casting position at a wide distance; removing a solidified cast body from the casting mold.

2. The method according to claim 1, wherein during the casting of the batch simultaneously with the movement of the induction coils in the pairs of induction coils from the melting position to the casting position, the current intensity in these induction coils is reduced.

3. The method according to claim 1, wherein the distance of the induction coils in the pairs of induction coil is increased from the melting position to the casting position by 5-100 mm.

4. The method according to claim 1, wherein the distance of the induction coils in the pairs of induction coil is increased from the melting position to the casting position by 10-50 mm.

5. An apparatus for levitation melting an electrically conductive material, comprising at least one pair of opposing induction coils with a core of a ferromagnetic material for levitating a batch by means of alternating electromagnetic fields, wherein the induction coils with their cores are movably arranged in each pair relative to each other and move between a small distance melting position and a wide distance casting position.

6. The apparatus according to claim 5, wherein the distance of the induction coils in the pairs of induction coils is increased from the melting position to the casting position by 5-100 mm.

7. The apparatus according to claim 5, wherein the distance of the induction coils in the pairs of induction coils is increased from the melting position to the casting position by 10-50 mm.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a lateral cross-sectional view of a casting mould below a melting area with ferromagnetic material, coils and a batch of conductive material.

(2) FIG. 2 is a top view on an arrangement with two coil pairs and a ferromagnetic element.

DESCRIPTION OF THE FIGURES

(3) The figures show preferred embodiments. They are for illustrative purposes only.

(4) FIG. 1 shows a batch (1) of conductive material which is in the influence area of alternating electromagnetic fields (melting area) generated by the coils (3). Below the batch (1) there is an empty casting mould (2) which is held in the filling area by a holder (5). The casting mould (2) has a funnel-shaped filling section (6). The holder (5) is suitable for lifting the casting mould (2) from a feeding position to a casting position, which is symbolized by the drawn arrow. A ferromagnetic material (4) is arranged in the core of the coils (3). The axes of the pair of coils (3) are horizontally aligned, wherein each two opposing coils (3) are forming a pair. In the figure the melting position of the coil arrangement at a short distance.

(5) The batch (1) is melted while levitating in the process according to the invention and cast into the casting mould (2) after the melt has occurred. For casting, the coils (3), as symbolised by the drawn arrow, are separated from each other until the Lorentz force of the field can no longer compensate the weight force of the batch (1).

(6) FIG. 2 shows a plan view of an arrangement with two pairs of coils and a ferromagnetic ring-shaped element (7). The ring-shaped element (7) is designed as an octagonal ring element. Each two coils (3) lying on an axis A, B with their ferromagnetic material (4) form a pair of coils. The coil axes A, B are arranged at right angles to each other. The figure shows the melting position of the coil arrangement with narrow distances between the coils (3). The ferromagnetic materials (4), which are positively seated in the ring-shaped element (7), then move together with their coils (3), as indicated by the double arrows, outwards for the casting the levitating melt.

LIST OF REFERENCE NUMERALS

(7) 1 batch 2 casting mould 3 induction coil 4 ferromagnetic material 5 holder 6 filling section 7 ring-shaped element