Metallurgical apparatus – With control means responsive to sensed condition – With temperature sensor
Patent
1991-08-14
1994-05-03
Group, Karl
Metallurgical apparatus
With control means responsive to sensed condition
With temperature sensor
266275, 501 96, 501 98, 374139, 136234, C21D 1100
Patent
active
053080440
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE TECHNOLOGY
The present invention relates to boron nitride (BN) ceramics having excellent resistance against fusing damages due to molten metal or other inorganic material and applications of the same ceramics.
TECHNICAL BACKGROUND
It has been known that BN ceramics are materials having very excellent antiwetting properties against melts of metal, glass and the like. Though BN ceramics having excellent antiwetting properties must be commonly used as materials for a furnace, in practice there are a number of reasons for preventing their use. A first reason is because when a member formed of the heretofore known BN ceramics comes into contact with melts of metal, glass and the like, it would be readily damaged by fusing. A second reason is because a member produced by sintering the heretofore known ceramics at the atmospheric pressure is quite indurable in use because of too low strength, hence it is a common practice to manufacture a BN ceramics member through a hotpress, and its manufacturing cost becomes high.
On the other hand, in order to continuously measure a temperature of molten metal within a molten metal container, it is a common practice to rely upon a thermocouple immersed in the molten metal. The thermocouple is inserted into a protective tube and it is put into the molten metal jointly with the protective tube. However, in connection to the use of the protective tube, there are the following problems:
1 Since the protective tube in the prior art put in molten metal at a high temperature such as that of molten steel is liable to be eroded, continuous temperature measurement is difficult.
2 In the conventional case, a protective tube is put into molten metal from its surface, and is held immovable by a holding member. According to this procedure in the prior art, the length of a protective tube becomes large, and its wall thickness must be made sufficiently large so that the protective tube may not be broken by flow of the molten metal. Consequently, there is a shortcoming that the protective tube becomes extremely expensive. In addition, a mechanism for holding and fixing the protective tube is complicated and handling thereof is intricate.
DISCLOSURE OF THE INVENTION
A first object of the present invention is to provide novel BN ceramics that are excellent in fusing damage resistivity against melts of metal, glass and the like and that have extremely high strength even when formed as a normal-pressure sintered article.
A second object of the present invention is to provide a molten metal container, in which a mechanism for putting a protective tube into molten metal from its surface and holding it as is the case with the prior art container, is made unnecessary by employing a protective cap that enables continuous measurement of the temperature of molten metal by means of a thermocouple and integrally assembling a temperature measuring function in a container wall.
The aforementioned first object can be achieved by providing BN ceramics containing 50 weight % or more of BN and 1 weight % or more and less than 50 weight % of AlN. According to results of tests conducted by the inventors of this invention, if AlN is contained in the range of 1.ltoreq.AlN<50 weight % in ceramics containing 50 weight % or more of BN, fusing damage resistivity of the aforementioned ceramics against melts of metal, glass and the like, in remarkably improved. If Y.sub.2 O.sub.3 is added to these BN ceramics in the range of 1.0-10.0 weight % relative to AlN, strength of the ceramics is greatly improved. Moreover, if at least a part of starting material powder of the BN component contained in the BN ceramics is prepared as amorphous BN powder or powder of material which produces amorphous BN in the course of sintering, the aforementioned effect of improving strength would reveal itself remarkably.
The above-mentioned second object can be achieved by providing a molten metal container, in which a protective cap formed of BN ceramics containing 50 weight % or more of BN and 1 weight % or more and les
REFERENCES:
patent: 3084060 (1963-04-01), Baer et al.
patent: 3544486 (1970-12-01), Passmore
patent: 3833389 (1974-09-01), Kaneya et al.
patent: 3854967 (1974-12-01), Reinmuth
patent: 3930875 (1976-01-01), Ochiai et al.
patent: 4358630 (1982-11-01), Falk
patent: 4377347 (1983-03-01), Hanmyo et al.
patent: 4430518 (1984-02-01), Nakajima et al.
patent: 4590034 (1986-05-01), Hirono et al.
patent: 4642298 (1987-02-01), Kuramoto et al.
patent: 4666873 (1987-05-01), Morris, Jr. et al.
patent: 4749416 (1986-06-01), Greenspan
patent: 4749556 (1988-06-01), Parrish et al.
patent: 4762729 (1988-08-01), Hirano et al.
patent: 4796671 (1989-01-01), Furushima et al.
patent: 4900526 (1990-02-01), Matsuda et al.
Chemical Abstracts, vol. 106, No. 4, Jan. 26, 1987, abstract No. 22283d, Columbus, Ohio, US; & JP-A-61 117 107 (Toshiba Tungaloy Co., Ltd) Apr. 6, 1986 *Abstract*.
Kurita Sumihiko
Kusumoto Mitsunori
Murata Akira
Nakamura Hiroshi
Nakashima Masazumi
Group Karl
Kabushiki Kaisha Kouransha
Marcantoni Paul
LandOfFree
Boron nitride ceramics and molten metal container provided with does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Boron nitride ceramics and molten metal container provided with , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Boron nitride ceramics and molten metal container provided with will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2109623