Patent ID: 8171981
Filing Date: 2012-05-08
Classification: B22D

Abstract:
1. A method of casting metal articles, said method comprising the steps of pouring a first molten metal into a mold in a furnace while the first molten metal is at a first temperature, providing a tank which holds a body of a second molten metal which is at a second temperature which is less than the first temperature, a container being submerged in the body of a second molten metal and being filled with the second molten metal, moving a lower portion of the mold containing the first molten metal downward from the furnace into an upper portion of the body of a second molten metal, transmitting heat at a first rate from the lower portion of the mold to the upper portion of the body of a second molten metal with the mold disposed above the container, moving the mold downwardly to move the lower portion of the mold downward into the container through an opening in an upper portion of the container, flowing a portion of the second molten metal disposed in the container upward through the opening in the upper portion of the container as the mold moves downward into the container, said step of flowing molten metal upward through the opening in the upper portion of the container includes reducing the quantity of the second molten metal in the container, heating the reduced quantity of the second molten metal in the container to a temperature which is greater than a temperature of the second molten metal in the upper portion of the body of a second molten metal disposed above the container, said step of heating the reduced quantity of the second molten metal in the container includes transmitting heat from a portion of the mold disposed in the container to the reduced volume of the second molten metal in the container, and, thereafter, transmitting heat from the portion of the mold disposed in the container to the reduced volume of the second molten metal in the container at a rate which is less than the first rate of heat transfer.