DEGASSING AND MICROSTRUCTURE REFINEMENT OF SHAPE CASTING ALUMINUM ALLOYS

• US 20170056971A1
• Filed: 09/01/2015
• Published: 03/02/2017
• Est. Priority Date: 09/01/2015
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Cogan, Christopher D., Genualdi, Andrew J., Wang, Qigui, Hess, Devin R., Traub, Jason R.
• Granted Patent: US 9,981,310 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22D 1/007 Treatment of the fused masses in the supply runners B22D1/002, B22D1/005 take precedence
• CPC Class Codes: B22D 21/04 Casting aluminium or magnesium no material; see B22D21/007
• CPC Class Codes: B22D 25/02 by its peculiarity of shape; of works of art cylinders, pistons B22D15/02
• CPC Class Codes: B22D 27/08 Shaking, vibrating, or turning of moulds
• CPC Class Codes: B22D 35/04 into moulds, e.g. base plates, runners
• CPC Class Codes: B22D 41/00 Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like B22D39/00, B22D43/00 take precedence
• CPC Class Codes: C22B 21/06 refining electrolytic refining C25C; C22B21/0046, C22B21/0061 take precedence
• CPC Class Codes: C22B 9/026 by acoustic waves, e.g. supersonic waves
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A degassing and grain refinement system for a cast aluminum-based component and a method of achieving both hydrogen gas presence reduction and grain size reduction in a cast aluminum-based component. Ultrasonic vibrations are imparted to both the liquid metal travel path from its source to the mold to achieve the reduction in hydrogen gas in the molten metal, as well as to one or more locations within the mold to achieve relatively small and equiaxed grains in the component upon solidification.

Claims

1. A degassing and grain refinement system for a cast aluminum-based component, said system comprising:

a molten metal conveyance assembly configured to fluidly couple a source of said molten metal to a mold with a shape therein that substantially defines said component; and

an apparatus cooperative with said conveyance assembly to impart ultrasonic vibrations thereto such that during at least a portion of its travel path between said source and said mold, said molten metal experiences reductions in hydrogen gas presence therein relative to no such vibrations being present, and further such that during a subsequent solidification of said molten metal in said mold, at least a portion of said component exhibits reductions in grain size relative to no such vibrations being present.

2. The system of claim 1, wherein said conveyance assembly comprises at least one of a launder tube, ladle and pour basin.

3. The system of claim 2, wherein said conveyance assembly comprises each of said launder tube, ladle, pour basin, sprue and runner.

4. The system of claim 3, wherein said ultrasonic vibration imparting apparatus is situated at discrete locations along at least the portion of said travel path that is defined by said launder tube.

5. The system of claim 4, wherein said ultrasonic vibration imparting apparatus is further situated at discrete locations along at least a portion of said travel path that is defined by said ladle, pour basin, sprue and runner.

6. The system of claim 4, wherein said ultrasonic vibration imparting apparatus is further situated in at least one location within said mold.

7. The system of claim 1, wherein said system prohibits an introduction of any grain-refining agents to said liquid metal.

8. A method of producing a cast component, said method comprising:

conveying a molten aluminum-based metal from its source to a mold;

applying ultrasonic vibrations to said liquid metal during at least a portion of its travel path between said source and said mold such that reductions in hydrogen gas presence is imparted to said liquid metal relative to no such vibrations being present; and

applying ultrasonic vibrations to said liquid metal during solidification thereof in said mold such that at least a portion of said component exhibits reductions in grain size relative to no such vibrations being present.

9. The method of claim 8, wherein said applying said ultrasonic vibrations to said liquid metal during at least a portion of its travel path between said source and said mold takes place in at least one of a launder tube, ladle and pour basin.

10. The method of claim 9, wherein said applying said ultrasonic vibrations to said liquid metal during at least a portion of its travel path between said source and said mold takes place at a plurality of discrete locations along a substantial entirety of said travel path defined by said launder tube, ladle and pour basin such that substantially continuous hydrogen gas presence reduction is imparted to said liquid metal during said conveying.

11. The method of claim 8, wherein said applying said ultrasonic vibrations to said liquid metal during solidification thereof in said mold comprises configuring said component as an automotive engine block such that a location within said mold where said ultrasonic vibration is applied comprises a bulkhead that is adjacent a crankshaft journal.

12. The method of claim 8, wherein said applying said ultrasonic vibrations to said liquid metal during solidification thereof in said mold comprises configuring said component as an automotive cylinder head such that a location within said mold where said ultrasonic vibration is applied comprises a combustion chamber.

13. The method of claim 8, wherein no grain-refining agents are added to said liquid metal.

14. The method of claim 8, wherein said applying ultrasonic vibrations comprises imparting a minimum acoustic intensity of 10 W/cm², 60% amplitude at 20 kHz.