Metal founding – Means to shape metallic material – Continuous or semicontinuous casting
Reexamination Certificate
1999-06-02
2002-09-10
Dunn, Tom (Department: 1725)
Metal founding
Means to shape metallic material
Continuous or semicontinuous casting
C164S463000, C164S415000
Reexamination Certificate
active
06446702
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method for producing a metallic ribbon of an amorphous metal or the like.
2. Description of the Related Art
As a method for producing a metallic ribbon, a single roll method using a single cooling roll is most popular at present.
FIG. 33
shows a principal portion of a conventional apparatus for producing a metallic ribbon by using the single roll method.
The single roll method comprises blowing a melt
103
out of a melt nozzle
102
adjacent to the top of the cooling surface of a cooling roll
101
, which is rotated at high speed, to draw out the melt
103
in the rotation direction (the direction of arrow A) of the cooling roll while rapidly solidifying it by the cooling surface of the cooling roll
101
.
The melt
103
blown out of the melt nozzle
102
forms a puddle
104
between the end of the melt nozzle
102
and the cooling surface of the cooling roll
101
, and the melt
103
is successively drawn out of the puddle
104
with rotation of the cooling roll
101
, and rapidly solidified on the surface of the cooling roll
101
to continuously form a ribbon
105
.
Where the material supplied in the single roll method has a highly oxidizable composition, the melt nozzle
102
is clogged due to oxidation of the material, hindering ejection of the melt.
In order to solve the problem of a conventional single roll method, a method is proposed in which the whole apparatus for producing a metallic ribbon is arranged in a chamber in which the oxygen concentration near the melt nozzle is deceased by an inert gas atmosphere, thereby preventing oxidation of material.
The method of forming an inert gas atmosphere in the chamber is very effective means for preventing clogging of the melt nozzle, but has a problem of workability because the whole apparatus is arranged in the chamber. For example, the conventional single roll method requires a complicated work comprising opening the chamber to fill a melt furnace or crucible with a metal mother material master alloy in each time of charge, closing the chamber, and then substituting air in the chamber with an inert gas atmosphere.
There is also a problem in which an additional equipment for holding an inert gas atmosphere in the chamber is expensive.
SUMMARY OF THE INVENTION
The present invention has been achieved for solving the above problems, and an object of the invention is to provide an apparatus for producing a metallic ribbon which can decrease the oxygen concentration of the atmosphere near a melt nozzle without providing a large-scale additional equipment exhibiting low workability, such as a chamber.
Unlike a conventional method, if only the vicinity of the melt nozzle can be brought into an inert gas atmosphere for decreasing the oxygen amount in order to prevent clogging of the melt nozzle, the whole apparatus for producing a metallic ribbon need not be placed in an inert gas atmosphere. Equipment in which only the vicinity of the melt nozzle is brought into an inert gas atmosphere permits improvement in workability and a decrease in equipment cost, as compared with a conventional chamber.
As a result of research with consideration of this point, the inventors found that by providing, at appropriate positions, air-cutoff means for preventing air from flowing into the periphery of the melt nozzle by rotation of the cooling roll, and gas flow means for supplying an inert gas to the periphery of the melt nozzle, the oxygen amount of the periphery of the melt nozzle can effectively be decreased.
An apparatus for producing a metallic ribbon of the present invention is achieved on the basis of the above findings. The apparatus comprises a cooling roll having a cooling surface for cooling a metal melt, a melt nozzle facing the cooling surface with a predetermined gap therebetween, roll periphery air-cutoff means which covers at least a portion of the periphery of the cooling roll and at least the melt blowout end of the melt nozzle, for preventing an inflow of air due to rotation of the cooling roll, wherein the body of the melt nozzle is arranged outside the roll periphery air-cutoff means.
In the apparatus for producing a metallic ribbon of the present invention, the roll periphery air-cutoff means is provided on at least the front side and the rear side on the basis of the melt nozzle (referred to as “the front side” and “the rear side” hereinafter) in the rotation direction of the cooling roll, and an air retention portion is provided on the front side in the rotation direction of the cooling roll.
The air retention portion may be provided either inside or outside the roll periphery air-cutoff means. The air retention portion preferably has an aperture area larger than the aperture area of the roll periphery air-cutoff means. In addition, the inside of the air retention portion may be divided by a plurality of partitions.
In the apparatus for producing a metallic ribbon of the present invention, the roll periphery air-cutoff means comprises at least a roll face air-cutoff plate provided ahead of the cooling roll on the front side in the rotation direction thereof, a pair of front air-cutoff plates provided on both sides of the cooling roll on the front side in the rotation direction thereof so as to hold the cooling roll therebetween and contact the roll face air-cutoff plate, a roll top air-cutoff plate located above the cooling roll so as to extend from the front side to the rear side in the rotation direction of the cooling roll and contact the upper edges of the roll front air-cutoff plates, and a roll surface air-cutoff plate provided on the rear side in the rotation direction of the cooling roll so as to contact the cooling surface of the cooling roll, wherein the roll top air-cutoff plate is provided in such a manner that it approaches the cooling surface of the cooling roll in the direction opposite to the rotation direction of the cooling roll, and the melt blowout end of the melt nozzle is passed through a nozzle mounting hole provided in the roll top air-cutoff plate so as to face the cooling surface of the cooling roll.
The roll top air-cutoff plate preferably evenly extends from the frond side in the rotation direction of the cooling roll to the cooling surface.
Also the roll top air-cutoff plate may extend from the frond side in the rotation direction of the cooling roll to the cooling surface in such a manner that it is curved along the inside of the roll periphery air-cutoff means.
Furthermore, at least one partition may be provided on the roll top air-cutoff plate so as to project into the roll periphery air-cutoff means.
Further, a passage hole is preferably provided in the roll face air-cutoff plate to pass the metallic ribbon formed by cooling with the cooling roll therethrough.
The apparatus for producing a metallic ribbon of the present invention further comprises gas flow supply means for supplying inert gases to the periphery of the melt nozzle.
The gas flow supply means is preferably provided at two positions on each of the front side and the rear side in the rotation direction of the cooling roll on the basis of the melt nozzle. Particularly, the two gas flow supply means arranged on the rear side in the rotation direction of the cooling roll preferably comprise one arranged so that a slit thereof faces the melt nozzle end, and the other arranged between the melt nozzle and the one gas flow supply means to supply a gas flow onto the gas flow supplied from the one gas flow supply means.
The gas flow velocity of the gas flow supply means is preferably 2 to 80 m/sec, and the gas flow rate is preferably 200 to 1400 l/min.
The inventors also found that by providing a plurality of gas flow supply means preferably including first gas flow supply means and second gas flow supply means, the oxygen amount of the periphery of the melt nozzle can effectively be decreased.
Namely, the apparatus for producing a metallic ribbon in which a metal melt is cooled by blowing it toward the cooling surface of the rota
Hatanai Takashi
Kojima Akinori
Makino Akihiro
Murakami Jun-ichi
Yamamoto Yutaka
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Dunn Tom
Lin I.-H.
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