In-situ homogenization of DC cast metals with additional quench

Patent metadata

Field	Value
Publication number	US-9415439-B2
Application number	US-201414333314-A
Country	US
Kind code	B2
Filing date	Jul 16, 2014
Priority date	Mar 23, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

The invention relates to a method and apparatus for direct chill casting ingots with in-situ homogenization. Large particles of eutectic material may form in the solid ingot and the metal may exhibit macrosegregation of alloying components, especially when large ingots are cast in this way. This can be alleviated by applying a first liquid coolant to the ingot emerging from the mold, removing the first liquid coolant at a certain distance along the ingot by means of a wiper, and then applying a second liquid coolant to perform a quench at a greater distance along the ingot. The quench raises the level of the molten sump in the ingot, which helps to overcome the indicated problems, without affecting the desired temperature rebound of the ingot shell (usually at least 425° C. (797° F.)) for a time effective to cause in-situ homogenization.

First claim

What is claimed is:

1. Apparatus for casting a metal ingot, comprising:
(a) a vertically oriented open-ended direct chill casting mold having a region where molten metal supplied to the mold through a mold inlet is peripherally confined by mold walls, thereby providing molten metal supplied to the mold with a peripheral portion, and a mold outlet receiving a movable bottom block;
(b) a chamber surrounding the mold walls for containing a primary coolant to cool the mold walls and thereby cool the peripheral portion of the molten metal to form an embryonic ingot having an external solid shell and an internal molten core;
(c) a movable support for the bottom block enabling the bottom block to advance away from the mold outlet in a direction of advancement while the molten metal is introduced into the mold through the inlet, thereby enabling the formation of an embryonic ingot having the molten core and solid shell;
(d) jets for directing a supply of a first coolant liquid onto the outer surface of the embryonic ingot;
(e) a wiper for removing the first coolant liquid from the outer surface of the embryonic ingot at a first location along the outer surface of the ingot where a cross section of the ingot perpendicular to the direction of advancement intersects a portion of the molten core; and
(f) nozzles operably coupled to the wiper to apply a second coolant liquid to the outer surface of the embryonic ingot at a second location where a cross section of the ingot perpendicular to the direction of advancement intersects a portion of the molten core, the nozzles being adapted to apply the second coolant liquid in an amount less than the first coolant liquid applied by the jets, wherein the nozzles are angled so that the second location is located a distance away from the first location sufficient to allow the outer shell to rebound in temperature by at least 100° C. between the first location and the second location.

2. The apparatus of claim 1 , wherein the mold is rectangular for producing a substantially rectangular ingot having wider rolling faces and narrower edge faces.

3. The apparatus of claim 2 , wherein said nozzles for applying the second coolant liquid are positioned adjacent to central regions of said wider rolling faces of the ingot emerging from said mold.

4. The apparatus of claim 1 , wherein each of said nozzles for applying said second cooling liquid is shaped to project a spray of said second coolant liquid.

5. The apparatus of claim 4 , wherein each of said nozzles is adapted to produce said sprays having a shape selected from the group consisting of V-shaped, conical and planar.

6. The apparatus of claim 1 , wherein said nozzles for applying said second coolant liquid are adapted to supply said liquid in amounts corresponding to 4 to 20% of amounts of said first coolant liquid supplied by said jets.

7. The apparatus of claim 1 , wherein the nozzles are angled such that the distance between the first location and the second location is between approximately 150 mm and approximately 450 mm.

8. The apparatus of claim 1 , wherein said mold is shaped and dimensioned to produce rectangular ingots having shorter end faces of at least 400mm in width.

9. The apparatus of claim 1 , wherein said wiper comprises heat-resistant elastomeric material shaped to engage and encircle said ingot.

10. The apparatus of claim 1 , wherein said wiper comprises a jet of fluid directed to remove said secondary coolant from said ingot.

11. The apparatus of claim 10 , wherein said jet of fluid is a jet of liquid.

12. The apparatus of claim 1 , wherein said wiper and said nozzles are positioned such that the second location is spaced from said first location along said ingot in said direction of advancement by a distance of approximately 150 to 450 mm.

13. The apparatus of claim 4 , wherein at least one of the nozzles is vertically offset from at least one other of the nozzles in the direction of advancement.

14. Apparatus for casting a metal ingot, comprising:
(a) a vertically oriented open-ended direct chill casting mold having a region where molten metal supplied to the mold through a mold inlet is peripherally confined by mold walls, thereby providing molten metal supplied to the mold with a peripheral portion, and a mold outlet receiving a movable bottom block;
(b) a chamber surrounding the mold walls for containing a primary coolant to cool the mold walls and thereby cool the peripheral portion of the molten metal to form an embryonic ingot having an external solid shell and an internal molten core;
(c) a movable support for the bottom block enabling the bottom block to advance away from the mold outlet in a direction of advancement while the molten metal is introduced into the mold through the inlet, thereby enabling the formation of an embryonic ingot having the molten core and solid shell;
(d) jets for directing a supply of a first coolant liquid onto the outer surface of the embryonic ingot;
(e) a wiper for removing the first coolant liquid from the outer surface of the embryonic ingot at a first location along the outer surface of the ingot where a cross section of the ingot perpendicular to the direction of advancement intersects a portion of the molten core; and
(f) nozzles operably coupled to the wiper for applying a second coolant liquid to the outer surface of the embryonic ingot at a second location where a cross section of the ingot perpendicular to the direction of advancement intersects a portion of the molten core, the nozzles being adapted to apply the second coolant liquid in an amount less than the first coolant liquid applied by the jets,
wherein the nozzles are angled such that the second location is located a distance away from the first location sufficient to allow the outer shell to rebound in temperature by at least 100° C. between the first location and the second location.

15. The apparatus of claim 14 , wherein each of said nozzles for applying said second cooling liquid is shaped to project a spray of said second coolant liquid.

16. The apparatus of claim 15 , wherein at least one of the nozzles is vertically offset from at least one other of the nozzles in the direction of advancement.

17. The apparatus of claim 15 , wherein each of said nozzles is configured to produce the sprays having a V-shape.

18. The apparatus of claim 14 , wherein the wiper is movable relative to the jets in the direction of advancement.

19. Apparatus for casting a metal ingot, comprising:
(a) a vertically oriented open-ended direct chill casting mold having a region where molten metal supplied to the mold through a mold inlet is peripherally confined by mold walls, thereby providing molten metal supplied to the mold with a peripheral portion, and a mold outlet receiving a movable bottom block;
(b) a chamber surrounding the mold walls for containing a primary coolant to cool the mold walls and thereby cool the peripheral portion of the molten metal to form an embryonic ingot having an external solid shell and an internal molten core;
(c) a movable support for the bottom block enabling the bottom block to advance away from the mold outlet in a direction of advancement while the molten metal is introduced into the mold through the inlet, thereby enabling the formation of an embryonic ingot having the molten core and solid shell;
(d) jets for directing a supply of a first coolant liquid onto the outer surface of the embryonic ingot;
(e) a wiper for removing the first coolant liquid from the outer surface of the embryonic ingot at a first

Assignees

• Novelis Inc

Inventors

• Fenton Wayne J
• Mcdermott Jeff
• Wagstaff Robert Bruce

Classifications

• B22D7/005

  from non-ferrous metals · CPC title

• B22D11/003

  Aluminium alloys · CPC title

• B22D11/049

  for direct chill casting, e.g. electromagnetic casting · CPC title

• B22D11/1248

  Means for removing cooling agent from the surface of the cast stock · CPC title

• B22D7/00

  Casting ingots, {e.g. from ferrous metals}(equipment for conveying molten metal B22D35/00) · CPC title