US4457355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and a method for making thixotropic metal slurries
Assignee: AEMP Corp
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Filing: 1983-10-26
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Granted: 1984-07-03
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Expires: 2003-10-26
Abstract
Abstract An apparatus and a method for forming a semi-solid thixotropic slurry. The apparatus includes a duplex mold arrangement for postponing solidification within the mold until the molten metal is within a magnetic field for providing magnetohydrodynamic stirring. The duplex mold includes a first portion of low thermal conductivity and a second portion of high conductivity.
Inventors
- 👤 Joseph Winter
- 👤 Jonathan A. Dantzig
- 👤 Derek E. Tyler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:41
CPC Classifications
B; B22; B22D; B22D11/00; B22D11/10; B22D11/11; B22D11/114; B22D11/115; C; C22; C22C; C22C1/00; C22C1/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
245 words
In an apparatus for continuously or semi-continuously forming a semi-solid thixotropic alloy slurry, said slurry comprising throughout its cross section degenerate dendrite primary solid particles in a surrounding matrix of molten metal, said apparatus comprising: means for containing molten metal, said containing means having a desired cross section; means for controllably cooling said molten metal in said containing means; and means for mixing said molten metal for shearing dendrites formed in a solidification zone as said molten metal is cooled for forming said slurry; said mixing means comprising a single two pole stator for generating a non-zero rotating magnetic field which moves transversely of a longitudinal axis of said containing means across the entirety of said cross section of said containing means and over said entire solidification zone, said moving magnetic field providing a magnetomotive stirring force directed tangentially of said containing means for causing said molten metal and slurry to rotate in said containing means, said magnetic force being of sufficient magnitude to provide said shearing of said dendrites, said magnetomotive force providing a shear rate of at least 500 sec. -1 ; the improvement wherein, said containing means includes a first portion of low thermal conductivity and a second portion of high thermal conductivity, said portion of low thermal conductivity extending into said magnetic field for postponing solidification within said containing means until said molten metal is within said magnetic field, thereby promoting the formation of a degenerate dendritic structure throughout the slurry.
Claim 2
Dependent Claim
245 words
In an apparatus for continuously or semi-continuously forming a semi-solid thixotropic alloy slurry, said slurry comprising throughout its cross section degenerate dendrite primary solid particles in a surrounding matrix of molten metal, said apparatus comprising: means for containing molten metal, said containing means having a desired cross section; means for controllably cooling said molten metal in said containing means; and means for mixing said molten metal for shearing dendrites formed in a solidification zone as said molten metal is cooled for forming said slurry; said mixing means comprising a single two pole stator for generating a non-zero rotating magnetic field which moves transversely of a longitudinal axis of said containing means across the entirety of said cross section of said containing means and over said entire solidification zone, said moving magnetic field providing a magnetomotive stirring force directed tangentially of said containing means for causing said molten metal and slurry to rotate in said containing means, said magnetic force being of sufficient magnitude to provide said shearing of said dendrites, said magnetomotive force providing a shear rate of at least 500 sec. -1 ; the improvement wherein, said containing means includes a first portion of low thermal conductivity and a second portion of high thermal conductivity, said portion of low thermal conductivity extending into said magnetic field for postponing solidification within said containing means until said molten metal is within said magnetic field, thereby promoting the formation of a degenerate dendritic structure throughout the slurry.
Claim 3
Dependent Claim
36 words
An apparatus as in claim 1 wherein said first portion of said mold comprises a layer of an insulating material and wherein said second portion of said mold is formed of a non-magnetic metal or alloy.
Claim 4
Dependent Claim
18 words
An apparatus as in claim 2 wherein said cooling means is arranged about said first portion of mold.
Claim 5
Dependent Claim
90 words
An apparatus as in claim 1 wherein said mold comprises a metal wall member for surrounding said molten metal and slurry, said wall member defining a top and bottom thereof and wherein a partial mold liner is provided internally of said mold wall extending from said top of said mold wall to a position intermediate said top and bottom of said mold wall to define said first portion of said mold, said liner leaving a portion of said metal wall member exposed which defines said second portion of said mold.
Claim 6
Dependent Claim
15 words
An apparatus as in claim 4 wherein said liner is formed from an insulating material.
Claim 7
Dependent Claim
13 words
An apparatus as in claim 5 wherein said magnetic field overlaps said liner.
Claim 8
Dependent Claim
14 words
An apparatus as in claim 6 wherein said mold wall has a cylindrical shape.
Claim 9
Dependent Claim
14 words
An apparatus as in claim 6 wherein said mold wall has a non-cylindrical shape.
Claim 10
Dependent Claim
19 words
An apparatus as in claim 6 wherein said mold comprises a mold for continuously or semi-continuously forming a rheocasting.
Claim 11
Dependent Claim
43 words
An apparatus as in claim 9 wherein said cooling means is arranged about said first portion of said mold and said magnetic field generating means is arranged below said cooling means so that said magnetic field at least in part overlaps said liner.
Claim 12
Dependent Claim
237 words
In a process for continuously or semi-continuously forming a semi-solid thixotropic alloy slurry, said slurry comprising throughout its cross section degenerate dendrite primary solid particles in a surrounding matrix of molten metal, said process comprising: providing a means for containing molten metal having a desired cross section; controllably cooling said molten metal in said containing means; and mixing said contained molten metal for shearing dendrites formed in a solidification zone as said molten metal is cooled for forming said slurry; said mixing step comprising generating solely with a two pole stator a non-zero rotating magnetic field which moves transversely of a longitudinal axis of said containing means across the entirety of said cross section of said containing means and over said entire solidification zone, said moving magnetic field providing a magnetomotive stirring force directed tangentially of said containing means for causing said molten metal and slurry to rotate in said containing means, said magnetomotive force being of sufficient magnitude to provide said shearing of said dendrites, said magnetomotive force providing a shear rate of at least 500 sec. -1 ; the improvement wherein a first region of low thermal conductivity and a second region of high thermal conductivity is provided within said containing means, said region of low thermal conductivity postponing solidification during said mixing step until said molten metal is within said magentic field, thereby promoting the formation of a degenerate dendritic structure throughout the slurry.
Claim 13
Dependent Claim
237 words
In a process for continuously or semi-continuously forming a semi-solid thixotropic alloy slurry, said slurry comprising throughout its cross section degenerate dendrite primary solid particles in a surrounding matrix of molten metal, said process comprising: providing a means for containing molten metal having a desired cross section; controllably cooling said molten metal in said containing means; and mixing said contained molten metal for shearing dendrites formed in a solidification zone as said molten metal is cooled for forming said slurry; said mixing step comprising generating solely with a two pole stator a non-zero rotating magnetic field which moves transversely of a longitudinal axis of said containing means across the entirety of said cross section of said containing means and over said entire solidification zone, said moving magnetic field providing a magnetomotive stirring force directed tangentially of said containing means for causing said molten metal and slurry to rotate in said containing means, said magnetomotive force being of sufficient magnitude to provide said shearing of said dendrites, said magnetomotive force providing a shear rate of at least 500 sec. -1 ; the improvement wherein a first region of low thermal conductivity and a second region of high thermal conductivity is provided within said containing means, said region of low thermal conductivity postponing solidification during said mixing step until said molten metal is within said magentic field, thereby promoting the formation of a degenerate dendritic structure throughout the slurry.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-03 | 1988-01-02 | 1988-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-03 | 1992-01-02 | 1992-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-03 | 1996-01-02 | 1996-07-03 | $7700.00 | Window Closed / Lapsed |