US3842895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal alloy casting process to reduce microsegregation and macrosegregation in casting
Assignee: Massachusetts Institute of Technology
•
Filing: 1972-01-10
•
Granted: 1974-10-22
•
Expires: 1992-01-10
Abstract
Abstract Apparatus for reducing segregation in metal alloy castings. The apparatus is operable to reduce segregate spacing (i.e., dendrite arm spacing) in short range segregation (microsegregation) and the overall magnitude of long range segregation (macrosegregation) in castings by controlling the heat flow process, in an active manner, during solidification, thereby reducing the time lapse between initiation and completion of the such solidification. The apparatus functions to decrease the distance within the material being cast between the liquidusisotherm and the solidus-isotherm by increasing the temperature of the liquid melt around the region of the liquidus-isotherm.
Inventors
- 👤 R Mehrabian
- 👤 M Flemings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:28
CPC Classifications
B; B22; B22D; B22D11/00; B22D11/12; B22D11/124
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
147 words
A method of reducing segregation in metal alloy castings in a continuous-casting process, that comprises, introducing a molten liquid metal of said alloy into a mold, withdrawing heat from one region of the liquid metal in the mold to effect solidification thereof, simultaneously adding heat in a controlled manner to the liquid metal, and internally controlling flow of said heat through the liquid metal to retard the velocity of the liquidus isotherm while maintaining substantially the velocity of the solidus isotherm, thereby reducing the width of liquid-solid mushy zone that exists between the liquidus and solidus isotherms and hence reducing both short range and long range segregation, the liquid metal being heated by superheating the molten metal prior to introduction to the mold to provide the necessary added heat and said flow of the heat being controlled by retarding convection of the liquid metal within the mold.
Claim 2
Independent Claim
147 words
A method of reducing segregation in metal alloy castings in a continuous-casting process, that comprises, introducing a molten liquid metal of said alloy into a mold, withdrawing heat from one region of the liquid metal in the mold to effect solidification thereof, simultaneously adding heat in a controlled manner to the liquid metal, and internally controlling flow of said heat through the liquid metal to retard the velocity of the liquidus isotherm while maintaining substantially the velocity of the solidus isotherm, thereby reducing the width of liquid-solid mushy zone that exists between the liquidus and solidus isotherms and hence reducing both short range and long range segregation, the liquid metal being heated by superheating the molten metal prior to introduction to the mold to provide the necessary added heat and said flow of the heat being controlled by retarding convection of the liquid metal within the mold.
Claim 3
Independent Claim
160 words
A method of reducing segregation in metal alloy castings in a continuous-casting process, that comprises, introducing a molten liquid metal of said alloy into a mold, withdrawing heat from one region of the liquid metal in the mold to effect solidification thereof, simultaneously adding heat in a controlled manner to the liquid metal, and internally controlling flow of said heat through the liquid metal to retard the velocity of the liquidus isotherm while maintaining substantially the velocity of the solidus isotherm, thereby reducing the width of liquid-solid mushy zone that exists between the liquidus and solidus isotherms and hence reducing both short range and long range segregation, a uni-directional magnet field of substantially constant magnitude throughout the region occupied by the liquid metal in the mold being introduced to control the flow of heat by retarding convection within the liquid metal during the solidification period and thereby raise the temperature of the melt in the vicinity of the liquidus isotherm.
Claim 4
Independent Claim
160 words
A method of reducing segregation in metal alloy castings in a continuous-casting process, that comprises, introducing a molten liquid metal of said alloy into a mold, withdrawing heat from one region of the liquid metal in the mold to effect solidification thereof, simultaneously adding heat in a controlled manner to the liquid metal, and internally controlling flow of said heat through the liquid metal to retard the velocity of the liquidus isotherm while maintaining substantially the velocity of the solidus isotherm, thereby reducing the width of liquid-solid mushy zone that exists between the liquidus and solidus isotherms and hence reducing both short range and long range segregation, a uni-directional magnet field of substantially constant magnitude throughout the region occupied by the liquid metal in the mold being introduced to control the flow of heat by retarding convection within the liquid metal during the solidification period and thereby raise the temperature of the melt in the vicinity of the liquidus isotherm.
Claim 5
Dependent Claim
87 words
In a method of casting a body of metal within which a liquid-solid mushy zone is established during solidification between solidus and liquidus isotherms defining a solid and a liquid zone, the steps of: superheating the liquid metal introduced into the liquid zone; and internally controlling the flow of heat through said liquid zone to maximize the heating of liquid metal adjacent to the liquid isotherm causing approach thereof toward the solidus isotherm, said flow of heat bEing controlled by magnetically retarding convection within the liquid zone.
Claim 6
Dependent Claim
87 words
In a method of casting a body of metal within which a liquid-solid mushy zone is established during solidification between solidus and liquidus isotherms defining a solid and a liquid zone, the steps of: superheating the liquid metal introduced into the liquid zone; and internally controlling the flow of heat through said liquid zone to maximize the heating of liquid metal adjacent to the liquid isotherm causing approach thereof toward the solidus isotherm, said flow of heat bEing controlled by magnetically retarding convection within the liquid zone.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |