System and method of increasing cooling rate of metal sand casting during solidification

Patent metadata

Field	Value
Publication number	US-2023211406-A1
Application number	US-202217568047-A
Country	US
Kind code	A1
Filing date	Jan 4, 2022
Priority date	Jan 4, 2022
Publication date	Jul 6, 2023
Grant date	—

Abstract

A system and method of increasing a cooling rate of a metal sand casting during solidification. The system includes a 3-D printed manufactured sand mold defining a mold cavity, a coolant inlet port extending into the manufactured sand mold, a myriad of coolant passageways surrounding a portion of the mold cavity, and a coolant outlet port in fluid communication with the coolant passageways. The system further includes a coolant vapor extraction system having a collection manifold in fluid connection with the outlet port of the sand mold. A molten metal is poured into the mold cavity and a liquid coolant is introduced into the sand mold. The liquid coolant changes state into a gas phase as it permeates through the sand mold, thereby increasing the cooling rate of the casting. The liquid coolant may be that of a liquid nitrogen.

First claim

What is claimed is:

1 . A system for increasing a cooling rate of a metal sand casting, comprising:
a sand mold defining a mold cavity, a coolant passageway surrounding a portion of the mold cavity, and a coolant inlet port in fluid connection with the coolant passageway; wherein the coolant inlet port is operable to receive a coolant in a liquid phase and the coolant passageway is operable to channel the coolant as the coolant transforms from the liquid phase to a gas phase.

2 . The system of claim 1 , wherein the coolant is a cryogenic liquid selected from the group consisting of argon, helium, and nitrogen.

3 . The system of claim 1 , wherein the coolant is liquid nitrogen.

4 . The system of claim 1 , wherein the coolant is a refrigerant selected from the group consisting of a chlorofluorocarbons (CFC), a hydrochlorofluorocarbons (HCFC), and a hydrofluorocarbons (HFC).

5 . The system of claim 1 , wherein the sand mold includes:
an internal mold surface defining the mold cavity; a first region located between the internal mold surface and the coolant passageway, wherein the first region includes a first permeability; and a second region located between the coolant passageway and an external boundary of the sand mold, wherein the second region includes a second permeability; wherein the first permeability is greater than the second permeability.

6 . The system of claim 1 , wherein the sand mold further defines a coolant outlet port, wherein the coolant outlet port is at least one of: (i) in indirect fluid communications with the coolant passageway such that the gas phase permeates the sand mold before entering the coolant outlet port and (ii) in direct fluid communication with the coolant passageway.

7 . The system of claim 6 further comprising a coolant vapor extraction system having a vacuum pump configured to extract the gas phase of the coolant from the sand mold.

8 . The system of claim 7 , wherein the coolant vapor extraction system includes a vacuum pump and a manifold in fluid connection with the vacuum pump, wherein the manifold includes a vacuum inlet in fluid connection with the outlet port of the sand mold.

9 . The system of claim 1 , wherein the sand mold includes:
an internal mold surface defining the mold cavity; and a heat sink disposed in the sand mold between the coolant passageway and the internal mold surface.

10 . The system of claim 1 , wherein the coolant inlet port is positioned at a lower portion of the sand mold or at an upper portion of the sand mold, and the coolant outlet port is positioned within the sand mold.

11 . A system for increasing a cooling rate of a metal sand casting, comprising:
a sand mold defining a mold cavity, and a coolant inlet port extending into a manufactured sand mold, wherein the coolant inlet port is operable to receive a cryogenic liquid; and wherein the sand mold includes a permeability sufficient for the cryogenic liquid to transform into a gas phase while permeating through the manufactured sand mold.

12 . The system of claim 11 , wherein the sand mold includes a myriad of coolant passageways surrounding a portion of the mold cavity, wherein the coolant passageways are in fluid connection with the coolant inlet port and operable to accommodate the cryogenic liquid changing from a liquid phase to the gas phase.

13 . The system of claim 12 , wherein the sand mold further includes a coolant gas outlet port in fluid communication with the coolant passageways.

14 . The system of claim 13 , further including a coolant vapor extraction system having a collection manifold in fluid connection with the coolant gas outlet port of the sand mold.

15 . The system of claim 14 , wherein the sand mold is manufactured by 3-D printing with varying sized grains of sand to define a first region having a first permeability and a second region having a second permeability, wherein the first permeability is greater than the second permeability.

16 . A method of increasing a cooling rate of a metal sand casting, comprising:
pouring molten metal into a mold cavity defined by a manufactured sand mold; and introducing liquid nitrogen in the manufactured sand mold such that the liquid nitrogen transforms from a liquid phase to a gas phase as the nitrogen permeates through the manufactured sand mold, thereby increasing a cooling rate of the molten metal.

17 . The method of claim 16 , further comprising:
3-D printing the manufactured sand mold, before pouring the molten metal, to define the mold cavity, a passageway surrounding a portion of the mold cavity, and an inlet port in fluid connection with the passageway; wherein the inlet port is operable to receive the liquid nitrogen and the passageway is operable to channel the liquid nitrogen as the liquid nitrogen transforms from the liquid phase to the gas phase.

18 . The method of claim 17 , further comprising extracting the gas phase from the manufactured sand mold by applying a vacuum.

19 . The method of claim 18 , wherein 3-D printing the manufactured sand mold further includes defining an outlet port in fluid connection with the passageway; and further includes applying the vacuum on the outlet port.

20 . The method of claim 19 , wherein 3-D printing the manufactured sand mold further includes disposing a heat sink between the passageway and the mold cavity.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Burkholder Steven L
• Gustafson Thomas W
• Wang Qigui
• Sachdev Anil K

Classifications

• B22D30/00

  Cooling castings, not restricted to casting processes covered by a single main group (accessories for cooling cast stock in continuous casting of metals B22D11/124; controlling or regulating processes or operations for cooling cast stock or mould in continuous casting of metals B22D11/22; chill casting B22D15/00) · CPC title

• B22D27/04 Primary

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

• B22C9/02

  Sand moulds or like moulds for shaped castings · CPC title

• B22D27/15

  by using vacuum · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title