Claims
- 1. A process for producing a refractory immersion nozzle useable for processing metal melts, which comprises:
- providing a mixture containing alumina having a maximum grain size of 150 microns, an aggregate having less tendency than alumina to form incrustations during use of then nozzle selected from the group consisting of mullite, silicon carbide and fused lime having a minimum grain size of 150 microns, 5 to 20 weight % of boron nitride, 5 to 20 weight % of graphite, the sum of boron nitride and graphite being 20 to 25 weight %, based on the dry weight of said mixture, a fluxing agent, a bonding agent selected from the group consisting of a resin, pitch and a mixture thereof, and a mixing liquid, with the proviso that said aggregate has a coarser grain size than the alumina in said mixture, and wherein said mixture contains said alumina in a weight ratio of from 30:70 to 70:30 for the weight ratio of said alumina to said aggregate;
- molding said mixture to form a shaped body; and
- drying said shaped body.
- 2. A process for producing a refractory immersion nozzle useable for processing metal melts, which comprises:
- providing a mixture containing alumina having a maximum grain size of 90 microns, an aggregate having less tendency than alumina to form incrustations during use of the nozzle selected from the group consisting of mullite, silicon carbide and fused lime having a minimum grain size of 90 microns, 5 to 20 weight % of boron nitride, 5 to 20 weight % of graphite, the sum of boron nitride and graphite being 20 to 25 weight %, based on the dry weight of said mixture, a fluxing agent, a bonding agent selected from the group consisting of a resin, pitch and a mixture thereof, and a mixing liquid, with the proviso that said aggregate has a coarser grain size than the alumina in said mixture, and wherein said mixture contains said alumina in a weight ratio of from 30:70 to 70:30 for the weight ratio of said alumina to said aggregate;
- molding said mixture to form a shaped body; and
- drying said shaped body.
- 3. A process for producing a refractory immersion nozzle useable for processing metal melts, which comprises:
- providing a mixture containing alumina having a maximum grain size of 44 microns, an aggregate having less tendency than alumina to form incrustations during use of the nozzle selected from the group consisting of mullite, silicon carbide and fused lime having a minimum grain size of 44 microns, 5 to 20 weight % of boron nitride, 5 to 20 weight % of graphite, the sum of boron nitride and graphite being 20 to 25 weight %, based on the dry weight of said mixture, a fluxing agent, a bonding agent selected from the group consisting of a resin, pitch and a mixture thereof, and a mixing liquid, with the proviso that said aggregate has a coarser grain size than the alumina in said mixture, and wherein said mixture contains said alumina in a weight ratio of from 30:70 to 70:30 for the weight ratio of said alumina to said aggregate;
- molding said mixture to form a shaped body; and
- drying said shaped body.
- 4. The process according to claim 1, 2 or 3 wherein said mixture further contains elemental silicon.
- 5. The process according to claim 1, 2 or 3 wherein said fluxing agent is a combination of a glass frit and a feldspar.
- 6. The process according to claim 5, wherein said fluxing agent includes a boron-containing fluxing agent.
- 7. The process according to claim 1, 2 or 3 which further comprises firing the dried shaped body.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3827424 |
Aug 1988 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of Ser. No. 07/386,593 filed Jul. 31, 1989, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (5)
Number |
Date |
Country |
3003046 |
Jul 1981 |
DEX |
3401999 |
Oct 1985 |
DEX |
3439954 |
May 1986 |
DEX |
60-9981 |
Mar 1985 |
JPX |
2067985 |
Aug 1981 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
386593 |
Jul 1989 |
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