Method and device for casting metal alloy ingots

Abstract

The invention relates to a method of casting a metal alloy ingot. The method includes providing an on one side open-ended mould having a mould cavity, positioning the open-ended mould such that the mould opening points side-wards or down-wards, providing a casting container with an upwardly positioned aperture, and filling said casting container with molten metal for one casting operation. The method also includes locating the casting container below the mould while the mould opening points side-wards or down-wards, and rotating the mould together with the casting container to a position whereby the mould opening points upwards such that the molten metal is conveyed into the open-ended mould until a desired thickness. Molten metal in the open-ended mould is cooled directionally through its thickness where the solidification front remains substantially monoaxial.

Claims

1. A method of casting a metal alloy ingot, comprising the following steps: providing an on one side open-ended mould comprising a plurality of sides and a bottom plate defining a mould cavity, said open-ended mould being pivotable around a horizontal rotational axis between a position so that the mould opening points upwards and a position so that the mould opening points side-wards or down-wards, and wherein the bottom plate of the mould is preferably provided with coolant means; positioning the open-ended mould such that the mould opening points side-wards or down-wards; providing a casting container with an upwardly positioned aperture; filling said casting container with molten metal for one casting operation; coupling the casting container to the open-ended mould so that the casting container is located below the mould while the mould opening points side-wards or down-wards; rotating the open-ended mould together with the casting container around the horizontal axis for approximately 45° to 180°, preferably 90° to 180°, from a position whereby the mould opening points side-wards or down-wards to a position whereby the mould opening points upwards such that the molten metal is conveyed into the open-ended mould until a desired thickness; and whereby the molten metal in the open-ended mould is cooled directionally through its thickness where a solidification front remains substantially monoaxial.

2. A method according to claim 1, wherein the metal alloy is an aluminium alloy, and preferably an aluminium wrought alloy.

3. A method according to claim 1, wherein the open-ended mould consists of four sides positioned upwards from the bottom plate of the mould.

4. A method according to claim 1, wherein at least one of the sides of the mould is provided with temperature control means.

5. A method according to claim 1, wherein the bottom plate of the mould is made from a metal and preferably provided with cooling channels for cooling medium passage.

6. A method according to claim 1, further comprising the step of releasing the casting container from the coupled position and removing the casting container from the mould.

7. A method according to claim 1, wherein a surface of the molten metal in the open-ended mould is heated via an external heat source.

8. A method according to claim 1, wherein at least the conveying of the molten metal from the casting container to the open-ended mould is carried out under a protective gas atmosphere.

9. A method according to claim 1, wherein at least the conveying of the molten metal from the casting container to the open-ended mould is carried out under a protective salt layer.

10. A casting system comprising an on one side open-ended mould comprising a plurality of sides and a bottom plate defining a mould cavity, said open-ended mould being pivotable mounted around a horizontal rotational axis between a position so that the mould opening points upwards and a position so that the mould opening points side-wards or down-wards, and wherein optionally at least one of the sides of the mould is provided with temperature control means, and wherein the bottom plate of the mould is provided with coolant means; and a casting container with an upwardly positioned aperture pivotable mountable around the horizontal rotational axis.

Description

DESCRIPTION OF THE DRAWINGS

[0035] The invention shall also be described with reference to the appended drawings, in which:

[0036] FIG. 1A to FIG. 1C show a partial cross-sectional schematic representation of the casting system used for the method.

[0037] FIG. 2A to FIG. 2C show a partial cross-sectional schematic representation of another embodiment of the casting system used for the method.

[0038] In the method according to this invention there is provided an on one side open-ended mould (1) comprising a plurality of sides (2,3) and a bottom plate (4) defining a mould cavity. The open-ended mould (1) is pivotable around a horizontal rotational axis (6) between a position so that the mould opening points upwards (see FIG. 1C) and a position so that the mould opening points side-wards (see FIG. 1A) or down-wards (non-shown), and wherein at least the side (2) of the mould (1) is provided with temperature control means (not shown) and the bottom plate of the mould is provided with temperature control means, in particular with coolant means (5). In addition there is provided a casting container (7) filled with a molten metal (8) for one casting operation. The casting container could be a ladle or a melting furnace. In the method the open-ended mould (1) is positioned such that the mould opening points side-wards (see FIG. 1A). At this step the mould (1) is empty and clean. In a next step the casting container (7) is coupled to the open-ended mould (1) so that the casting container is located below the mould (1) while the mould opening points side-wards. Next (see FIG. 1B) rotating or tilting the open-ended mould (1) together with the casting container (7) around the horizontal axis (6) for at least 45°, and preferably approximately 90°, to a position wherein the mould opening points upwards such that the molten metal is conveyed into the open-ended mould until a desired thickness (see FIG. 1C). When the molten metal is being conveyed progressively to the open-ended mould is may flow through a ceramic foam filter (9) for removing non-metallic inclusions in the molten metal and the creation of turbulence is to be avoided. When the molten metal is in the open-ended mould by extracting heat via the bottom plate (4) it is cooled directionally through its thickness where the solidification front remains substantially monoaxial.

[0039] In another embodiment of the method the open-ended mould (1) is positioned initially such that the mould opening points down-wards. The feature numbering in FIG. 2A is the same as for FIG. 1A. In practice this would mean that the mould is located substantially above the casting container (7) (see FIG. 2A). In a next step (see FIG. 2B) the mould and the casting container are being rotated or tilted around a horizon axis (6) for approximately 180° to a position wherein the mould opening points upwards such that the molten metal is conveyed into the open-ended mould until a desired thickness (see FIG. 2C). In this embodiment of the method the open-ended mould can be coupled or connected to the casting container via a seal (10). This would allow for an improved control of the atmosphere above the molten metal, for example by using an inert gas environment, and results in a reduced hydrogen pick-up in the molten metal. This would allow the casting of alloys which are very sensitive to any hydrogen or nitrogen pick-up such as Al—Mg—Li and Al—Cu—Li alloys.

[0040] The invention is not limited to the embodiments described before, which may be varied widely within the scope of the invention as defined by the appending claims.