Claims
- 1. A process for heating a ceramic shaped part, which comprises providing a ceramic shaped part which exhibits a power conversion of 5 to 15 kW per dm.sup.3 of said shaped part and which at ambient temperature has a homogeneously distributed carbon skeleton, and heating said shaped part inductively, beginning at the ambient temperature, at a frequency of 2 to 15 kHz or at a frequency greater than 100 kHz, wherein said carbon skeleton is formed in said shaped part by providing a ceramic shaped part containing a carbonizable material selected from the group consisting of a synthetic resin, pitch, tar, a carbonizable derivative of said resin, pitch or tar, and a mixture thereof, and carbonizing said carbonizable material at 400.degree. to 1000.degree. C. and said shaped part is a wearable steelmaking apparatus component selected from the group consisting of a plug, a sleeve, an immersion nozzle and a slide valve plate for contacting liquid metal.
- 2. The process according to claim 1, wherein said shaped part is made from a starting mixture comprising 2 to 75% by weight of a material which yields said carbon skeleton.
- 3. The process according to claim 2, wherein said starting mixture comprises 3 to 70% by weight of said material which yields said carbon skeleton.
- 4. The process according to claim 1, wherein said carbonizable material is a phenolic resin or a mixture of phenolic resins.
- 5. The process according to claim 1, wherein said ceramic shaped part contains a ceramic material selected from the group consisting of aluminum oxide, magnesium oxide, silicon oxide, zirconium oxide and a mixture thereof.
- 6. The process according to claim 1, wherein said shaped part is made from a starting mixture comprising refractory oxides and up to 30% by weight of graphite based on the total weight of the refractory oxides and graphite.
- 7. The process according to claim 1, wherein said power conversion is about 10 kW per dm.sup.3.
- 8. The process according to claim 1, wherein said heating of said shaped part is effected on location in a steelwork prior to bringing said shaped part into contact with liquid metal for steelmaking.
- 9. The process according to claim 1, wherein said heating is effected to fire said shaped part.
- 10. The process according to claim 1, wherein said carbon skeleton is formed in said shaped part by providing a green preform for the shaped part containing a carbonizable material and enveloped by a jacket for inductive heating from room temperature, heating said jacket inductively, thereby heating said green preform by convection or radiation or both at least in an outer region of said preform to carbonize said carbonizable material and form said carbon skeleton in said outer region, removing said jacket from said preform, and further heating said preform inductively to completely form said carbon skeleton.
- 11. The process according to claim 10, wherein said jacket and said preform are heated inductively in succession by the same inductor.
- 12. The process according to claim 10, wherein said jacket is constructed of a material selected from the group consisting of metal and carbon fibers.
- 13. The process according to claim 10, wherein said jacket contains a member selected from the group consisting of molybdenum disilicide and recrystallized silicon carbide.
- 14. The process according to claim 10, wherein said jacket is a layer containing a member selected from the group consisting of graphite, carbon and a mixture thereof on said preform, and after said carbon skeleton is formed in said outer region of said preform said layer is fired and burned off said preform in an oxidizing atmosphere.
Priority Claims (1)
Number |
Date |
Country |
Kind |
41 25 916.5 |
Aug 1991 |
DEX |
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Parent Case Info
This application is a continuation of now abandoned application Ser. No. 07/924,935, filed Aug. 5, 1992, now abandoned.
US Referenced Citations (12)
Foreign Referenced Citations (4)
Number |
Date |
Country |
2844686 |
Apr 1980 |
DEX |
55-10374 |
Jan 1980 |
JPX |
3-94967 |
Apr 1991 |
JPX |
1581058 |
Dec 1980 |
GBX |
Continuations (1)
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Number |
Date |
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Parent |
924935 |
Aug 1992 |
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