IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0080921
(2002-02-22)
|
우선권정보 |
DE-0009565 (2001-02-28) |
발명자
/ 주소 |
- Bardelmeier, Udo
- Minarski, Peter
|
출원인 / 주소 |
|
대리인 / 주소 |
Fulbright & Jaworski L.L.P.
|
인용정보 |
피인용 횟수 :
7 인용 특허 :
9 |
초록
▼
In the partial thermochemical vacuum treatment of metallic workpieces ( 1 ), in particular in the carburization and case hardening of workpieces ( 1 ) of case-hardening steel in a carbon-containing atmosphere, surface regions ( 3, 4, 5, 6 ) to be treated and surface regions not to be treated abut on
In the partial thermochemical vacuum treatment of metallic workpieces ( 1 ), in particular in the carburization and case hardening of workpieces ( 1 ) of case-hardening steel in a carbon-containing atmosphere, surface regions ( 3, 4, 5, 6 ) to be treated and surface regions not to be treated abut one another. In order to restrict the surface treatment to the cavities ( 2 ) of the workpieces ( 1 ) the external surface regions not to be treated are covered by reusable dismountable mould bodies ( 11 ) of a temperature-resistant material with at least one mould cavity ( 15 ). In this connection the mould body ( 11 ) consisting of a lower part ( 12 ) and an upper part ( 13 ) with openings ( 12 b, 13 b ) encloses several workpieces ( 1 ) in such a way that no treatment takes place on the external surface regions of the workpieces ( 1 ). An electrically conducting mould body ( 11 ) is suitable in particular for a thermochemical treatment under the action of a plasma. Graphite or CFC is used as material for the mould bodies ( 11 ). In such a mould body the workpieces can be subjected before the carburization to a heating procedure, as well after the carburization to procedures such as diffusion, gas quenching and optionally further treatments such as deep cooling and/or annealing.
대표청구항
▼
1. A process for the partial thermochemical vacuum treatment of metallic workpieces comprising:simultaneously vacuum treating several metallic workpieces having defined cavities and a region to be treated and an external surface region that is not to be treated, wherein the workpieces are installed
1. A process for the partial thermochemical vacuum treatment of metallic workpieces comprising:simultaneously vacuum treating several metallic workpieces having defined cavities and a region to be treated and an external surface region that is not to be treated, wherein the workpieces are installed in a mold body having at least one mold cavity and several openings trough which a carbon containing atmosphere enters the cavities of the workpieces, in-wherein the workpieces are enclosed in the mold body in such a way that no thermochemical treatment takes place on the external surface and the region to be treated is thermochemically treated, wherein the thermochemical treatment is carried out under the action of a plasma and that the mold body consists of an electrically conducting material. 2. A process according to claim 1, wherein in each case at least one surface region of the cavity of the workpiece is screened by a sleeve that is inserted to protect the screened region of the cavity against a thermochemical treatment, whereas at least one additional surface region of the cavity is subjected to the thermochemical treatment. 3. A process according to claim 1, wherein the metallic workpiece comprises steel and the thermochemical treatment is carburization. 4. A process according to claim 1, wherein a mold body having a plurality of mold cavities receives one workpiece per mold cavity. 5. A process according to claim 1, wherein the mold body is formed as a housing with an upper part and that at least the upper part has openings that communicate with the cavities in the workpieces and through which the carbon-containing atmosphere enters the said workpieces. 6. A process according to claim 1, wherein between the surface regions not being treated of the workpieces and the mold body sleeves are employed for sealing purposes. 7. A process according to claim 1, wherein a plurality of mold bodies are combined to form a batch. 8. A process according to claim 1, wherein the process is carried out in a vacuum range between 10 Pa and 3000 Pa. 9. A process according to claim 2, wherein the process is carried out with plasma voltages of between 200 and 2000 volts. 10. A process according to claim 9, wherein the plasma is used in pulsed form. 11. A process according to claim 10, wherein the connection time is between 10 and 200 μs and the pause time is between 10 and 500 μs. 12. A process according to claim 1, wherein the carbon-containing gas is at least one hydrocarbon selected from the group consisting of methane, ethane, propane and acetylene. 13. A process according to claim 12, wherein at least one gas selected from the group consisting of argon, nitrogen and hydrogen is added to the carbon-containing gas wherein, the proportion of the at least one hydrocarbon being chosen between 10 and 90 vol. %. 14. A process according to claim 1, wherein the material for the mold bodies is graphite. 15. A process according to claim 1, wherein a material that does not exhibit any distortion phenomena at a temperature of at least 1050° C. is used as material for the mold bodies. 16. A process according to claim 3, wherein the plasma-side ends of the at least one mold cavity of the mold bodies are formed in a plasma-tight manner opposite the respective workpiece. 17. A process according to claim 1, wherein the workpieces within the mold body are subjected to a heating procedure before the carburization. 18. A process according to claim 1, wherein the workpieces within the mold body are subjected to a diffusion procedure after the carburization. 19. A process according to claim 1, wherein the workpieces within the mold body are subjected to a high pressure gas quenching after the diffusion procedure. 20. A process according to claim 19, wherein the workpieces within the mold body are subjected after the high pressure gas quenching to at least one further treatment from the group consisting of deep cooling and annealing. 21. An appar atus for use in a single-chamber unit or in a multi-chamber throughflow unit for the partial thermochemical vacuum treatment of metallic workpieces comprising at least one reusable mold body that comprises a temperature-resistant material to cover surface regions of a workpiece not to be treated during the treatment of the remaining surface regions, wherein several mold cavities are provided in the mold body for the insertion of several workpieces, wherein the workpieces can be enclosed in the mold cavity in such a way that no thermochemical treatment takes place on the external surfaces of the workpieces; wherein the mold body is formed as a housing and comprises an electrically conducting material and the workpieces can be enclosed in the mold cavity in such a way that when using a plasma no plasma is formed between the mold body and the workpiece. 22. An apparatus according to claim 21, wherein the mold body has several openings that communicate with the cavities of the in each case associated workpieces. 23. An apparatus according to claim 21, wherein the mold body is formed as a housing with an upper part, and that at least the upper part has several openings that communicate with the cavities. 24. An apparatus according to claim 23, wherein the meld body comprises a lower part that has several openings, wherein the axes of the openings in the upper part and in the lower part coincide. 25. An apparatus according to claim 24, wherein between the lower part and upper part of the mold body there is arranged a separating groove running along the circumference, which permits a telescopic movement between the lower part and upper part. 26. An apparatus according to claim 21, wherein the plasma-side ends of openings in the mold body opposite the respective workpiece are formed in a plasma-tight manner. 27. An apparatus according to claim 21, having sleeves that can be inserted between the workpiece and a lower part on the one hand and between the workpiece and an upper part on the other hand, and which match the workpiece in such a way that surface regions of the workpieces not being treated are excluded from the thermochemical treatment. 28. An apparatus according to claim 21, wherein a plurality of mold bodies are combined by means of a transporting frame to form a batch. 29. An apparatus according to claim 28, wherein the transporting frame comprises crosspieces for arranging mold bodies next to one another and on top of one another. 30. An apparatus according to claim 21, wherein the mold body consists of graphite. 31. An apparatus according to claim 21, wherein the mold bodies comprise a material that docs not exhibit any distortion phenomena at a temperature of at least 1050° C. 32. A process according to claim 8, wherein the process is carried out in a vacuum range between 50 Pa and 1000 Pa. 33. A process according to claim 31, wherein the process is carried out with plasma voltages between 300 and 1000 volts. 34. An apparatus according to claim 31, wherein the material does not exhibit any distortion phenomena at a temperature of up to at least 1200° C. 35. A process for the partial thermochemical vacuum treatment of metallic workpieces comprising:simultaneously vacuum treating several metallic workpieces having defined cavities and a region to be treated and an external surface region that is not to be treated, wherein the workpieces are installed in a mold body baying at least one mold cavity and several openings through which a carbon containing atmosphere enters the cavities of the workpieces, wherein the workpieces are enclosed in the mold body in such a way that no thermochemical treatment takes place on the external surface and the region to be treated is thermochemically treated, wherein the thermochemical treatment is carried out under the action of a plasma and that the mold body consists of an electrically conducting material wherein the mold body is formed as a housing with an upper part and that at least the upper part has openings that communicate with the cavities in the workpieces and through which the carbon-containing atmosphere enters the workpieces, wherein sleeves are positioned between the surface regions of the workpieces not being treated and the mold body. 36. A process according to claim 1, wherein the mold bodies comprise carbon fiber composite. 37. An apparatus according to claim 21, wherein the mold body comprises carbon fiber composite. 38. An apparatus according to claim 21, wherein that the mold body is arranged within an evacuable chamber with an inlet for at least one hydrocarbon and is connected as a cathode for the formation of a plasma.
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