Non-contacting molten metal flow control

Patent metadata

Field	Value
Publication number	US-10464127-B2
Application number	US-201514719050-A
Country	US
Kind code	B2
Filing date	May 21, 2015
Priority date	May 21, 2014
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

Systems and methods are disclosed for using magnetic fields (e.g., changing magnetic fields) to control metal flow conditions during casting (e.g., casting of an ingot, billet, or slab). The magnetic fields can be introduced using rotating permanent magnets or electromagnets. The magnetic fields can be used to induce movement of the molten metal in a desired direction, such as in a rotating pattern around the surface of the molten sump. The magnetic fields can be used to induce metal flow conditions in the molten sump to increase homogeneity in the molten sump and resultant ingot.

First claim

What is claimed is:

1. An apparatus comprising:
a mold for accepting molten metal, wherein the mold comprises one or more stationary mold walls for solidifying the molten metal into a solidifying ingot;
a bottom block lowerable to support the solidifying ingot, wherein a molten sump of the solidifying ingot extends from a surface of the molten metal to a point below the one or more mold walls;
a submersible feed tube couplable to a metal source and positioned to supply the molten metal to the molten sump; and
at least one non-contact flow inducer positioned above the surface of the molten metal for generating a changing magnetic field proximate the surface of the molten metal for inducing molten flow in the molten metal, wherein the induced molten flow is configured to excite a velocity of the molten metal adjacent a transitional region between the molten metal and the solidifying ingot.

2. The apparatus of claim 1 , wherein the at least one non-contact flow inducer includes a first non-contact flow inducer positioned opposite a mold centerline from and parallel with a second non-contact flow inducer.

3. The apparatus of claim 1 , wherein the at least one non-contact flow inducer is positioned proximate a corner of the mold for inducing the molten flow through the corner of the mold.

4. The apparatus of claim 3 , wherein the at least one non-contact flow inducer includes a plurality of permanent magnets positioned on a rotating plate that rotates about a rotational axis.

5. The apparatus of claim 1 , wherein the at least one non-contact flow inducer comprises at least one permanent magnet rotating about an axis.

6. The apparatus of claim 5 , wherein the axis is positioned parallel to a mold centerline.

7. The apparatus of claim 5 , wherein the axis is positioned along a radius extending from a center of the mold.

8. The apparatus of claim 1 , wherein the at least one non-contact flow inducer is positioned to induce the molten flow at the surface of the molten metal towards the one or more mold walls.

9. The apparatus of claim 1 , wherein at least one of the one or more stationary mold walls contacts the molten metal while the molten metal solidifies into the solidifying ingot.

10. A method comprising:
introducing molten metal into a mold cavity comprising one or more stationary mold walls for solidifying the molten metal into a solidifying ingot, wherein introducing the molten metal comprises passing the molten metal from a metal source to a molten sump of the solidifying ingot using a submersible feed tube;
lowering a bottom block of a mold cavity as the molten metal begins to solidify within the mold cavity, wherein the molten sump extends from an upper surface of the molten metal to a point below the one or more mold walls;
generating a changing magnetic field proximate the upper surface of the molten metal; and
inducing molten flow in the molten metal by generating the changing magnetic field using at least one non-contact flow inducer positioned above the surface of the molten metal, wherein the induced metal flow is configured to excite a velocity of the molten metal adjacent a transitional region between the molten metal and the solidifying ingot.

11. The method of claim 10 , further comprising:
inducing sympathetic flow in the molten metal by inducing the molten flow.

12. The method of claim 11 , wherein inducing the sympathetic flow comprises inducing a sympathetic flow to mix the molten metal and reduce a thickness of the transitional region to approximately less than 3 millimeters.

13. The method of claim 11 , wherein inducing the sympathetic flow comprises inducing a sympathetic flow to mix the molten metal and reduce a thickness of the transitional region to approximately less than 1 millimeter.

14. The method of claim 10 , wherein inducing the molten flow comprises:
inducing a first molten flow towards a mold centerline of the mold cavity; and
inducing a second molten flow towards the mold centerline and in a direction opposite the first molten flow.

15. The method of claim 10 , wherein inducing the molten flow comprises inducing the molten flow in a generally circular direction.

16. The method of claim 10 , wherein inducing the molten flow comprises inducing the molten flow through a corner of the mold cavity.

17. A system comprising:
a mold for accepting molten metal, wherein the mold comprises one or more stationary mold walls for solidifying the molten metal into a solidifying ingot;
a bottom block lowerable to support the solidifying ingot, wherein a molten sump of the solidifying ingot extends from a surface of the molten metal to a point below the one or more mold walls;
a submersible feed tube couplable to a metal source and positioned to supply the molten metal to the molten sump;
a non-contacting flow inducer positioned directly above the surface of the molten metal; and
a magnetic source included in the non-contacting flow inducer for generating a changing magnetic field for inducing molten flow under the surface of the molten metal and increasing mixing of the molten metal.

18. The system of claim 17 , wherein the magnetic source includes at least one permanent magnet rotating about a rotational axis at a speed between approximately 10 revolutions per minute and approximately 500 revolutions per minute.

19. The system of claim 17 , wherein the non-contacting flow inducer is oriented to induce the molten flow in a direction parallel at least one of the one or more mold walls.

20. The system of claim 17 , wherein the non-contacting flow inducer is oriented to induce the molten flow in a direction perpendicular a radius extending from a center of the mold.

21. The system of claim 17 , wherein the non-contacting flow inducer is positioned to induce molten flow at the surface of the molten metal towards at least one of the one or more mold walls.

22. The system of claim 17 , wherein at least one of the one or more stationary mold walls contacts the molten metal while the molten metal solidifies into the solidifying ingot.

23. An apparatus comprising:
a mold for accepting molten metal, wherein the mold comprises one or more stationary mold walls for solidifying the molten metal into a solidifying ingot;
a bottom block lowerable to support the solidifying ingot, wherein a molten sump of the solidifying ingot extends from a surface of the molten metal to a point below the one or more mold walls;
a submersible feed tube couplable to a metal source and positioned to supply the molten metal to the molten sump; and
at least one magnetic source positioned above the mold for generating an alternating magnetic field proximate the surface of the molten metal for directing movement of metal oxides on the surface of the molten metal and increasing mixing and velocity of the molten metal adjacent a transitional region between the molten metal and the solidifying ingot.

24. The apparatus of claim 23 , wherein the at least one magnetic source comprises at least one permanent magnet rotating about an axis.

25. The apparatus of claim 24 , wherein the at least one magnetic source comprises a plurality of permanent magnets arranged in a Halbach array.

26. The apparatus of claim 24 , wherein the at least one magnetic source further comprises a radiant heat reflector and a conductive heat inhibitor surrounding the at least one permanent magnet.

27. The appara

Assignees

• Novelis Inc

Inventors

• Wagstaff Samuel R
• Fenton Wayne J
• Wagstaff Robert B
• Felberbaum Milan
• Bischoff Todd F
• Kosmicki Tina J

Classifications

• B22D27/02

  Use of electric or magnetic effects {(for continuous casting B22D11/015, B22D11/11)} · CPC title

• B22D41/507 Primary

  giving a rotating motion to the issuing molten metal · CPC title

• B22D37/00 Primary

  Controlling or regulating the pouring of molten metal from a casting melt-holding vessel ({B22D11/18,} B22D39/00, B22D41/00 take precedence) · CPC title

• B22D11/18

  for pouring (B22D11/20 takes precedence) · CPC title

• B22D46/00

  Controlling, supervising, not restricted to casting covered by a single main group, e.g. for safety reasons (controlling or regulating in general G05) · CPC title