Patent US4243420A successfully refreshed from Google Patents.
US4243420A
Expired / Lapsed
US
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Particulate material for forming molds and method for producing same
Assignee: Hitachi Ltd
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Filing: 1979-04-17
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Granted: 1981-01-06
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Expires: 1999-04-17
Abstract
Abstract Particulate material for forming molds produced by mixing particulate refractory material with one material selected from the group consisting of colloidal silica, colloidal alumina, colloidal zirconia and ethyl silicate, drying the mixture and allowing same to set, and crushing the dried mixture into particulate form again. The particulate material includes refractory particles provided with a coat of silica or alumina or zirconia on the surface and increases the strength and surface precision of a mold.
Inventors
- 👤 Junji Sakai
- 👤 Syogo Morimoto
- 👤 Takashi Shimaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:08
CPC Classifications
B; B22; B22C; B22C1/00; B22C1/16; B22C1/20; B22C1/205
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
143 words
A method for producing a precision casting mold comprising the steps of: mixing refractory material in particulate form with a coating material selected from the group consisting of colloidal silica, colloidal alumina, colloidal zirconia and ethyl silicate to form a mix; further adding an aqueous solution of ammonium carbonate to the mix when the coating material is ethyl silicate; drying said mix and allowing the dried mix to set; crushing the mix to form a particulate composition; admixing the resultant particulate composition with a binder comprising an aqueous solution of hydrolysed ethyl silicate and with a hardening and gelling agent to form a slurry; forming the slurry into a mold having a desired shape and allowing the mold to gel; and immersing the gelled mold in a hardening liquid to allow the mold to completely harden and thereafter drying and firing the mold.
Claim 2
Independent Claim
143 words
A method for producing a precision casting mold comprising the steps of: mixing refractory material in particulate form with a coating material selected from the group consisting of colloidal silica, colloidal alumina, colloidal zirconia and ethyl silicate to form a mix; further adding an aqueous solution of ammonium carbonate to the mix when the coating material is ethyl silicate; drying said mix and allowing the dried mix to set; crushing the mix to form a particulate composition; admixing the resultant particulate composition with a binder comprising an aqueous solution of hydrolysed ethyl silicate and with a hardening and gelling agent to form a slurry; forming the slurry into a mold having a desired shape and allowing the mold to gel; and immersing the gelled mold in a hardening liquid to allow the mold to completely harden and thereafter drying and firing the mold.
Claim 3
Dependent Claim
66 words
A method for forming a mold according to claim 1, wherein said particulate composition is produced by mixing 400 cc of a hydrolytic solution of ethyl silicate, 1 kg of particles of fused silica and 8 cc of an aqueous solution of ammonium carbonate, by kneading the mixture and allowing the mixture to set, and finally by crushing the set mixture into particles of 5-20 mesh.
Claim 4
Dependent Claim
51 words
A method for forming a mold according to claim 1, wherein said particulate composition is produced by mixing 900 cc of colloidal silica and 3 kg of zirconia powder, by kneading the mixture and allowing the mixture to set and by finally crushing the set mixture into particles of 20-200 mesh.
Claim 5
Dependent Claim
51 words
A method for forming a mold according to claim 1, wherein said particulate composition is produced by mixing 100 cc of colloidal alumina and 500 grams of artificial graphite, by kneading the mixture and allowing the mixture to set, and by finally crushing the set mixture into particles of 20-200 mesh.
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) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |