Homogenization and heat-treatment of cast metals

Patent metadata

Field	Value
Publication number	US-9802245-B2
Application number	US-201514730610-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Oct 28, 2005
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A method of casting a metal ingot with a microstructure that facilitates further working, such as hot and cold rolling. The metal is cast in a direct chill casting mold, or the equivalent, that directs a spray of coolant liquid onto the outer surface of the ingot to achieve rapid cooling. The coolant is removed from the surface at a location where the emerging embryonic ingot is still not completely solid, such that the latent heat of solidification and the sensible heat of the molten core raises the temperature of the adjacent solid shell to a convergence temperature that is above a transition temperature for in-situ homogenization of the metal. A further conventional homogenization step is then not required. The invention also relates to the heat-treatment of such ingots prior to hot working.

First claim

What is claimed is:

1. An apparatus, comprising:
a casting mold having an inlet, an outlet, and a mold cavity;
a supply of coolant liquid arranged to direct the coolant liquid to flow along an exterior surface of an embryonic ingot emerging from the outlet;
a wiper spaced a distance from the outlet for removing the coolant liquid from the exterior surface of the embryonic ingot;
a wiper support coupled to the wiper for adjusting the distance between the wiper and the outlet; and
a controller coupled to the wiper support and operable to adjust the distance between the wiper and the outlet during casting of the embryonic ingot.

2. The apparatus of claim 1 , wherein the wiper support is selected from the group consisting of an electrical jack, a pneumatic jack, and a hydraulic jack.

3. The apparatus of claim 1 , further comprising a sensor positioned between the wiper and the outlet to measure a surface temperature of the exterior surface of the embryonic ingot, wherein the controller is coupled to the sensor to adjust the distance between the wiper and the outlet based on the measured surface temperature.

4. The apparatus of claim 1 , wherein the wiper includes a surface facing the outlet, wherein the surface is shaped to form a pool of coolant adjacent the embryonic ingot.

5. The apparatus of claim 1 , wherein the wiper has a shaped contour passing through at least two planes that are parallel the casting mold at the outlet and that are spaced at different distances from the outlet.

6. The apparatus of claim 1 , further comprising a quenching pool for accepting the embryonic ingot, wherein the quenching pool is spaced from the wiper at a distance that allows the embryonic ingot to undergo homogenization before entering the quenching pool.

7. A system for forming ingots from molten metal, comprising:
a casting mold for forming an embryonic ingot;
a coolant supply arranged to direct liquid coolant to the surface of the embryonic ingot adjacent an outlet of the direct chill casting apparatus;
an adjustable wiper positioned to remove the liquid coolant from the exterior surface of the embryonic ingot, wherein the adjustable wiper is movable between a first position and a second position, and wherein the first position is located between the casting mold and the second position; and
a controller coupled to the wiper support and operable to move the adjustable wiper during casting of the embryonic ingot.

8. The system of claim 7 , wherein the controller is coupled to an actuator of the wiper support for moving the adjustable wiper between the first position and the second position.

9. The system of claim 8 , wherein the actuator is selected from the group consisting of an electrical jack, a pneumatic jack, and a hydraulic jack.

10. The system of claim 7 , further comprising
a sensor positioned between the adjustable wiper and the casting mold to measure a surface temperature of the exterior surface of the embryonic ingot, wherein the controller is coupled to the sensor
for moving the adjustable wiper in response to the measured surface temperature.

11. The apparatus of claim 7 , wherein the adjustable wiper includes a surface facing the casting mold, wherein the surface is shaped to form a pool of coolant adjacent the embryonic ingot.

12. The apparatus of claim 7 , wherein the adjustable wiper has a shaped contour passing through at least two planes that are parallel the casting mold and that are spaced at different distances from the outlet.

13. The apparatus of claim 7 , further comprising a quenching pool for accepting the embryonic ingot, wherein the quenching pool is spaced from the adjustable wiper at a distance that allows the embryonic ingot to undergo homogenization before entering the quenching pool.

14. An in-situ homogenization system, comprising:
a wiper having an aperture sized to pass an embryonic ingot therethrough, wherein the wiper is positionable at a distance from a casting mold forming the embryonic ingot, and wherein the wiper is shaped to remove liquid coolant applied to an exterior surface of the embryonic ingot between the wiper and the casting mold;
a wiper support coupled to the wiper for adjusting the distance between the wiper and the casting mold; and
a controller coupled to the wiper support and operable to adjust the distance between the wiper and the casting mold as the embryonic ingot passes through the aperture.

15. The system of claim 14 , wherein the wiper support is selected from the group consisting of an electrical jack, a pneumatic jack, and a hydraulic jack.

16. The apparatus of claim 14 , further comprising a sensor positionable between the wiper and the casting mold to measure a surface temperature of the exterior surface of the embryonic ingot, wherein the controller is coupled to the sensor to adjust the distance between the wiper and the casting mold based on the measured surface temperature.

17. The apparatus of claim 14 , wherein the wiper includes a surface facing the outlet, wherein the surface is shaped to form a pool of coolant adjacent the embryonic ingot.

18. The apparatus of claim 14 , wherein the wiper has a shaped contour passing through at least two planes that are parallel the casting mold at the outlet and that are spaced at different distances from the outlet.

Assignees

• Novelis Inc

Inventors

• Wagstaff Robert Bruce
• Fenton Wayne J

Classifications

• Y10T29/49988

  Metal casting · CPC title

• B22D27/04

  Influencing the temperature of the metal, e.g. by heating or cooling the mould · CPC title

• B22D11/22

  for cooling cast stock or mould · CPC title

• B22D11/225

  for secondary cooling · CPC title

• B22D11/003

  Aluminium alloys · CPC title