CA2088054C - Method of and apparatus for producing metal powder - Google Patents
Method of and apparatus for producing metal powderInfo
- Publication number
- CA2088054C CA2088054C CA002088054A CA2088054A CA2088054C CA 2088054 C CA2088054 C CA 2088054C CA 002088054 A CA002088054 A CA 002088054A CA 2088054 A CA2088054 A CA 2088054A CA 2088054 C CA2088054 C CA 2088054C
- Authority
- CA
- Canada
- Prior art keywords
- cooling liquid
- cooling
- tubular body
- metal powder
- producing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F2009/0804—Dispersion in or on liquid, other than with sieves
- B22F2009/0812—Pulverisation with a moving liquid coolant stream, by centrifugally rotating stream
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
- B22F2009/084—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid combination of methods
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Abstract
A method and a device for making metallic powder, by which irregularity in cooling speed is hardly caused, high speed cooling and solidification are made possible, and fine grain powder can easily be obtained. Cooling liquid is spouted along the inner peripheral surface of a cooling cylinder (1) so that a cooling liquid layer (9) is formed which moves while turning along the inner peripheral surface of said cylinder (1), toward the side of a cooling liquid discharging end of said cylinder (1); molten metal (25) is supplied into the inner space (23) inside said tooting layer (9); jetting gas (26) directed toward the cooling liquid layer (9) is blown to said molten metal (25) for fragmentation and molten metal thus fragmented is supplied to the cooling liquid layer (9); and cooling liquid containing metallic powder solidified in the cooling liquid layer (9) is discharged from the discharging end of the cooling cylinder (1) to the outside.
Description
J.
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METHOD 0f AND APPARATUS FOR PRODUCxNG METAL POWDER
TECHNTCAL FIELD
The present invention relates to a mothod of and an apparatus for producing metal powdexs by supply-ing a molten metal to a cooling liquid layer in a swirling movement.
B7~.CKGk~OUND ART
Rapidly solxdi.f~.ed metal powders are in the foz~m o~ fine crystal grains and can be adapted to contain alloy elements to supersaturation. so that the extrudates and sintered materials prepared from rapidly solidified powdexs are superior to materials prepared by melting in characteristics and have attracted attention as materials for making machine parts) Tt~.e methods of producing rapidly solidified metal powders include the rotary dxum method as disclosed in Examined Japanese Patent fubliGatiori HEZ
1-49769. With this method, a rapidly solidified metal powdex is prepared by rotating a cooling drum having a bottom and containing a cooling liquid to centxifugally form a cooling liquid layer ovex the inner periphery of the drum, and injecting a molten metal into the cooling liquid layer to divide tk~e ~~8~~~~
metal by the cooling liquid layer. 3.n a swira.ing motion.
On the other hand, U,S. Patents No. 4,7a7,935 and No. 4,869 g 69 disclose methods and systems fox producing a metal powder by atomizing a molten metal stream into spherical molten droplets and supplying the droplets to a swirling downward flow of cooling gas within a cooling cylinder fox cooling and solidifica-Lion.
The rotary drum method .is adapted Eor a so-called batchwise operation and therefore has the problem o~ being low in productivity. Furthermore, the speed of rotation of the cooling drum. which is lim-ited,poses the probelm in that it is difficult to give an increased flow velocity to the cooling liquid layer and to obtain a fine powder.' On the other hand, the production methods of the U.S. patents are adapted to continuously prepare a fins powder of 0.1 micrometer in size to a coarse powder of. about 1000 micrometers. With these produc-Lion methods, however, the cooling rate is limited to about lOZ - 107.oC/see and fails to achieve a suffi-dent rapid Cooling effect Further because the molten droplets encounter difficulity in undergoing a swirling motion in the central portion of the swirling cooling gas flow and are cooled at a reduced ra.ter there arises the problem that the quality of the powder produced is liable to involve variations.
Additionally, the cooling cylinder needs to have a considerably large size to form therein a swirling cooling gas flow which is suitable for cooling the molten droplets.
This poses another problem in that the methods are difficult to practice readily in view of the installation space and equipment cost.
An object of the present invention, which has been accomplished in view of the above problems, is to provide a method of producing metal powders which is less likely permit variations in cooling rate, ensures rapid solidification at a great cooling rate and readily gives fine particles, and a production apparatus which is suitable for practicing this method.
DISCLOSURE OF THE INVENTION
Broadly speaking, the present invention overcomes the problems of the prior art by providing a method of producing a metal powder, comprising the steps of:
providing a nonrotating fixed cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
injecting a cooling liquid generally tangentially into the nonrotating fixed cooling tubular body along an inner peripheral surface thereof with a velocity to form a cooling liquid layer moving toward a cooling liquid discharge end of the tubular body while swirling along the tubular body inner peripheral surface and leaving a liquid free central space within the tubular body;
decreasing downward flow velocity of the injected cooling liquid by providing the cooling tubular body with a narrower width at a lower portion of the tubular body than at an upper portion of the tubular body, the narrower width being provided by (a) providing a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, (b) providing the ring with an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from the inner peripheral surface, and (c) providing the ring at a location within said cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end;
supplying a molten metal to the space inside the cooling liquid layer;
applying a gas jet to the molten metal to divide the molten metal and supply the divided molten metal to the cooling liquid layer; and discharging the cooling liquid containing a metal powder solidified in the liquid layer from the cooling liquid discharge end of the tubular body to outside.
The invention also provides an apparatus for producing a metal powder, comprising:
a nonrotating fixed cooling tubular body, the cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
a cooling liquid injection channel means for injecting a cooling liquid generally tangentially into the tubular body and creating a cooling liquid layer along an inner peripheral surface thereof;
the cooling tubular body having a narrower width at a lower portion of the tubular body than at a level at which the cooling liquid injection channel means injects the cooling liquid;
molten metal supply means for supplying a molten metal into a space inside the cooling liquid layer formed by the cooling liquid injected from the injection channel;
gas jet injection means for producing a gas jet to divide the molten metal and supply the divided molten metal to the cooling liquid layer;
cooling liquid supply means for supplying the cooling liquid to the cooling liquid injection channel;
wherein the narrower width includes a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, the ring having an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from said inner peripheral surface; and the ring being located within the cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end.
According to the present invention, the cooling liquid injected from the injection channel into the tubular body along the inner peripheral surface thereof moves toward an opening at the discharge end of the body while swirling along the inner peripheral surface, whereby a cooling liquid layer of approximately uniform inside diameter is formed on the inner peripheral surface of the tubular body by virtue of the centrifugal force of the swirling motion.
This layer is formed by the cooling liquid which is newly supplied at all times, and therefore readily maintained at a constant temperature. Since the cooling medium is a liquid, the medium is superior to gases in cooling ability. For these reasons, the cooling liquid layer can be small in the radius of swirling motion and in thickness, with the result that the cooling tubular body for forming the layer therein can be compact.
The gas jet injected from the injection means and directed toward the cooling liquid layer is forced against the molten metal supplied from the molten metal supply means into the space inside the cooling liquid to divide the molten metal. The divided molten m~v-t~
(molten droplets) is sputtered toward the cooling liquid layer, and a11 the droplets are reliably supplied to and injected into the liquid layer. The molten droplets injected into the cooling liquid layer produce a vapor of the cooling liquid therearound, whereas the vapor is rapidly l:eleased from around the droplets. The reason is that since the liquid layer has a flow velocity which increases toward the center of the swirl-ing motion, i.e., a gradient distrikaution of flow velocities. the molten droplets injected into the layer are in rotating motion. Consequently, the molten droplets have their outer peripheral surfaces always held in contact with the cooling liquid, are therefore cooled at a high rate and make particles which are free of surface contamination with the vaQox. Further because the size a~ molten droplets to be foam@d by dividing is adjustable easily by Controlling the flow velocity of the gas jet and the flow rate thereof, the deszred rapidly solidified fine powder can be prepared with ease. Moreover, the cooling liquid layer remains unchanged and stabilized in temperature and surf ace condition, permitting the molten droplets to cool un.dex a definite condition to give a powder of stabilized quality,.
~~~~~<.D~
Since the cooling liquid layez is continuous-ly formed, the powder can be produced also continuously by continuously supplying the mo~.t.er~ metal. and continuously applying the gas jet to the molten metal to dzvide the metal and supply the divided metal. to the liquid layer. The metal powder solidified within the cooling liquid layer is cantinuously discharged from the liquid discharge end opening of the tubular body along with the cooling liquid.
It is desired to provide a closure for the ~.~.quid discharge end opening of the tubular body and to attach a di9charge pipe to the closure so that the cooling 7.~.c~ui.d containing the metal powder can be discharged to outside thz'oufh the pipe with the pipe filled with the cooling 7.~.quid. When the liquid is discharged in this way, the space inside the cooling liquid layer can be filled with the jet-forming gas easily. The molten droplets can be prevented from os~~.dat~.on by using a suitable nonoxidizi.ng gas, suckz as inert gas ox reducing gas, as this gas.
aRZ~~ ~~sc~z~Txc~ o~ zHE D~~.wxrrcs FIG. 1 is a fragmezatary sectional view of a metal powder production apparatus embodying th,e invention;
FIG. 2 is a i:ragmentaxy sectional view of
~p$$0'~~~
saECxFxcATxoN
METHOD 0f AND APPARATUS FOR PRODUCxNG METAL POWDER
TECHNTCAL FIELD
The present invention relates to a mothod of and an apparatus for producing metal powdexs by supply-ing a molten metal to a cooling liquid layer in a swirling movement.
B7~.CKGk~OUND ART
Rapidly solxdi.f~.ed metal powders are in the foz~m o~ fine crystal grains and can be adapted to contain alloy elements to supersaturation. so that the extrudates and sintered materials prepared from rapidly solidified powdexs are superior to materials prepared by melting in characteristics and have attracted attention as materials for making machine parts) Tt~.e methods of producing rapidly solidified metal powders include the rotary dxum method as disclosed in Examined Japanese Patent fubliGatiori HEZ
1-49769. With this method, a rapidly solidified metal powdex is prepared by rotating a cooling drum having a bottom and containing a cooling liquid to centxifugally form a cooling liquid layer ovex the inner periphery of the drum, and injecting a molten metal into the cooling liquid layer to divide tk~e ~~8~~~~
metal by the cooling liquid layer. 3.n a swira.ing motion.
On the other hand, U,S. Patents No. 4,7a7,935 and No. 4,869 g 69 disclose methods and systems fox producing a metal powder by atomizing a molten metal stream into spherical molten droplets and supplying the droplets to a swirling downward flow of cooling gas within a cooling cylinder fox cooling and solidifica-Lion.
The rotary drum method .is adapted Eor a so-called batchwise operation and therefore has the problem o~ being low in productivity. Furthermore, the speed of rotation of the cooling drum. which is lim-ited,poses the probelm in that it is difficult to give an increased flow velocity to the cooling liquid layer and to obtain a fine powder.' On the other hand, the production methods of the U.S. patents are adapted to continuously prepare a fins powder of 0.1 micrometer in size to a coarse powder of. about 1000 micrometers. With these produc-Lion methods, however, the cooling rate is limited to about lOZ - 107.oC/see and fails to achieve a suffi-dent rapid Cooling effect Further because the molten droplets encounter difficulity in undergoing a swirling motion in the central portion of the swirling cooling gas flow and are cooled at a reduced ra.ter there arises the problem that the quality of the powder produced is liable to involve variations.
Additionally, the cooling cylinder needs to have a considerably large size to form therein a swirling cooling gas flow which is suitable for cooling the molten droplets.
This poses another problem in that the methods are difficult to practice readily in view of the installation space and equipment cost.
An object of the present invention, which has been accomplished in view of the above problems, is to provide a method of producing metal powders which is less likely permit variations in cooling rate, ensures rapid solidification at a great cooling rate and readily gives fine particles, and a production apparatus which is suitable for practicing this method.
DISCLOSURE OF THE INVENTION
Broadly speaking, the present invention overcomes the problems of the prior art by providing a method of producing a metal powder, comprising the steps of:
providing a nonrotating fixed cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
injecting a cooling liquid generally tangentially into the nonrotating fixed cooling tubular body along an inner peripheral surface thereof with a velocity to form a cooling liquid layer moving toward a cooling liquid discharge end of the tubular body while swirling along the tubular body inner peripheral surface and leaving a liquid free central space within the tubular body;
decreasing downward flow velocity of the injected cooling liquid by providing the cooling tubular body with a narrower width at a lower portion of the tubular body than at an upper portion of the tubular body, the narrower width being provided by (a) providing a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, (b) providing the ring with an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from the inner peripheral surface, and (c) providing the ring at a location within said cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end;
supplying a molten metal to the space inside the cooling liquid layer;
applying a gas jet to the molten metal to divide the molten metal and supply the divided molten metal to the cooling liquid layer; and discharging the cooling liquid containing a metal powder solidified in the liquid layer from the cooling liquid discharge end of the tubular body to outside.
The invention also provides an apparatus for producing a metal powder, comprising:
a nonrotating fixed cooling tubular body, the cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
a cooling liquid injection channel means for injecting a cooling liquid generally tangentially into the tubular body and creating a cooling liquid layer along an inner peripheral surface thereof;
the cooling tubular body having a narrower width at a lower portion of the tubular body than at a level at which the cooling liquid injection channel means injects the cooling liquid;
molten metal supply means for supplying a molten metal into a space inside the cooling liquid layer formed by the cooling liquid injected from the injection channel;
gas jet injection means for producing a gas jet to divide the molten metal and supply the divided molten metal to the cooling liquid layer;
cooling liquid supply means for supplying the cooling liquid to the cooling liquid injection channel;
wherein the narrower width includes a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, the ring having an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from said inner peripheral surface; and the ring being located within the cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end.
According to the present invention, the cooling liquid injected from the injection channel into the tubular body along the inner peripheral surface thereof moves toward an opening at the discharge end of the body while swirling along the inner peripheral surface, whereby a cooling liquid layer of approximately uniform inside diameter is formed on the inner peripheral surface of the tubular body by virtue of the centrifugal force of the swirling motion.
This layer is formed by the cooling liquid which is newly supplied at all times, and therefore readily maintained at a constant temperature. Since the cooling medium is a liquid, the medium is superior to gases in cooling ability. For these reasons, the cooling liquid layer can be small in the radius of swirling motion and in thickness, with the result that the cooling tubular body for forming the layer therein can be compact.
The gas jet injected from the injection means and directed toward the cooling liquid layer is forced against the molten metal supplied from the molten metal supply means into the space inside the cooling liquid to divide the molten metal. The divided molten m~v-t~
(molten droplets) is sputtered toward the cooling liquid layer, and a11 the droplets are reliably supplied to and injected into the liquid layer. The molten droplets injected into the cooling liquid layer produce a vapor of the cooling liquid therearound, whereas the vapor is rapidly l:eleased from around the droplets. The reason is that since the liquid layer has a flow velocity which increases toward the center of the swirl-ing motion, i.e., a gradient distrikaution of flow velocities. the molten droplets injected into the layer are in rotating motion. Consequently, the molten droplets have their outer peripheral surfaces always held in contact with the cooling liquid, are therefore cooled at a high rate and make particles which are free of surface contamination with the vaQox. Further because the size a~ molten droplets to be foam@d by dividing is adjustable easily by Controlling the flow velocity of the gas jet and the flow rate thereof, the deszred rapidly solidified fine powder can be prepared with ease. Moreover, the cooling liquid layer remains unchanged and stabilized in temperature and surf ace condition, permitting the molten droplets to cool un.dex a definite condition to give a powder of stabilized quality,.
~~~~~<.D~
Since the cooling liquid layez is continuous-ly formed, the powder can be produced also continuously by continuously supplying the mo~.t.er~ metal. and continuously applying the gas jet to the molten metal to dzvide the metal and supply the divided metal. to the liquid layer. The metal powder solidified within the cooling liquid layer is cantinuously discharged from the liquid discharge end opening of the tubular body along with the cooling liquid.
It is desired to provide a closure for the ~.~.quid discharge end opening of the tubular body and to attach a di9charge pipe to the closure so that the cooling 7.~.c~ui.d containing the metal powder can be discharged to outside thz'oufh the pipe with the pipe filled with the cooling 7.~.quid. When the liquid is discharged in this way, the space inside the cooling liquid layer can be filled with the jet-forming gas easily. The molten droplets can be prevented from os~~.dat~.on by using a suitable nonoxidizi.ng gas, suckz as inert gas ox reducing gas, as this gas.
aRZ~~ ~~sc~z~Txc~ o~ zHE D~~.wxrrcs FIG. 1 is a fragmezatary sectional view of a metal powder production apparatus embodying th,e invention;
FIG. 2 is a i:ragmentaxy sectional view of
2~~~~'~!~
another embodiment of apparatus;
FIG. 3 is a fragmentary sectional view of a third embodiment of apparatus;
FIG. 4 is a fragmentary sectional. view of a fourth embodiment of apparatus;
FzG. 5 is a sectional diagram illustrating a molten metal continuous feeder;
fIG. 6 is an overall layout of metal powder continuous production equipment;
FIG. 7 is a fragmentary sectional view of a metal powder production apparatus used in a preparation example of the invention;
FIG. 8 is a diagram showing the relation in position between a thin. stream of molten metal and a gas bet used in the preparation ea~ample and as seen from above;
FIG. 9 is a graph showing the particle size distribution of metal powders prepared in the example and a comparative preparation erample; and FIG. 10 is a graph showing the relation between the cooling rate and the particle size of metal powder prepared in another preparation example of the invention.
SEST MODE Of CAR~XZNG OUT THE INVENTION
FzG. 7. shows a metal powder production r 2~~~~~~
apparatus embodying the present invention. The apparatus comprises a cooling tubular body 1 having an inner peripheral surface for forming a cooling liquid layer 9 thereon, a crucible 15 serving as means for supplying a molten motal 25 in the form of a thin down-ward stream to a space 23 inside the cooling liquid layer 9, a pump 7 serving as means for supplying a cooling liquid to the tubular body 1, and a jet nozzle 24 serving as gas jet injection means far injecting a gas bet 26 for dividing the downward stream of molten metal 25 into molten droplets and supplying the droplets to the cooling liquid layer 9.
The tubular body 1 is hollow cylindrical, is installed with its axis positioned vertically and has an upper~end opening provided with an annular closure 2. The closure 2 is centrally formed With an opening
another embodiment of apparatus;
FIG. 3 is a fragmentary sectional view of a third embodiment of apparatus;
FIG. 4 is a fragmentary sectional. view of a fourth embodiment of apparatus;
FzG. 5 is a sectional diagram illustrating a molten metal continuous feeder;
fIG. 6 is an overall layout of metal powder continuous production equipment;
FIG. 7 is a fragmentary sectional view of a metal powder production apparatus used in a preparation example of the invention;
FIG. 8 is a diagram showing the relation in position between a thin. stream of molten metal and a gas bet used in the preparation ea~ample and as seen from above;
FIG. 9 is a graph showing the particle size distribution of metal powders prepared in the example and a comparative preparation erample; and FIG. 10 is a graph showing the relation between the cooling rate and the particle size of metal powder prepared in another preparation example of the invention.
SEST MODE Of CAR~XZNG OUT THE INVENTION
FzG. 7. shows a metal powder production r 2~~~~~~
apparatus embodying the present invention. The apparatus comprises a cooling tubular body 1 having an inner peripheral surface for forming a cooling liquid layer 9 thereon, a crucible 15 serving as means for supplying a molten motal 25 in the form of a thin down-ward stream to a space 23 inside the cooling liquid layer 9, a pump 7 serving as means for supplying a cooling liquid to the tubular body 1, and a jet nozzle 24 serving as gas jet injection means far injecting a gas bet 26 for dividing the downward stream of molten metal 25 into molten droplets and supplying the droplets to the cooling liquid layer 9.
The tubular body 1 is hollow cylindrical, is installed with its axis positioned vertically and has an upper~end opening provided with an annular closure 2. The closure 2 is centrally formed With an opening
3 for supplying the molten metal to the interior of the cooling tubular body 1 therethrough. The cooling body 1 is formed at an upper portion thereof. with a plural-Z0 ity of cooling liquid injection tubes 4 having a cooling liquid injection ehannel 5 and arranged at equal spacings circumferentially of the body. The channel 5 has an outlet (discharge outlet) which is so opened as to inject the cooling liquid into the ZS tubular body 1 along the inner peripheral sur~aee ~08~0~~
tangentially thereof. The center line of the opening portion of the channel 5 extends obliquely downward at an angle of about 0 to about 20~ with re9pect to a plane orthogonal to the a:cis of the tubular body, Th2 liqu~.d infection tubes 4 are connected by piping to a tank 8 by way of a pump 7, which forces up the cooling liquid within the tank 8 and supplies the liquid to the inner peripheral surface of the tubular body 1 through the injection channels S of the injection tubes 4. Thus the cooling liquid layer 9 is formed on the inner peripheral surface of the tubular body 1. This layer flows down while swirling along the inner peripheral surface. The tank 8 is provided with an unillustrated a cooling liquid replenishing pipe, A oooler may be provided suitably within the tank 8 or at an inter-mediate portion of a channel for recycling the cooling liquid. Water is generally used as the cooling liquid since water is excellent in cooling ability and in~
expansive. Alternatively, oil ox like liquid for use in quenching hot metals may be used. When water is to be used, it is desired to remove dissolved oxygen from the water before use. Oxygen removing devices are readily available commercially.
A ring 10 for adjusting the thickness of the cooling liquid layer 9 is attached to an inner peri-11 ~0~80~4 pheral lower portion o~ the cooling tubular body 1 with bolts removably and replaceably. The thickness adjusting ring 10 limits the downward flow veloc~.ty of the cooling liquid, whereby, the cooling liquid layer 9 can be readily formed with an approximately uniform inside diameter at a low fJ.ow rate. The tubular body 1 has a cooling liquid discharge end, i.e., a lower-end opening, which is provided with a hollow cylindrical draining net 11. A funnel-shaped powder collecting container 12 is attached to the lower end of the net 11.
A cooling liquid collecting cover 13 is provided around and covers the net. 11. 'the collecting cover 13 is provided in its bottom with a liquid outlet 1~, which is connected to the tank 8 by piping.
The crucible 15 serving as fi.he molten metal supply means and disposed above the cooling tubuJ.ar body 1 is made of graphite, silicon nitride ox ~.~.ke refrac-tory and comprises a hollow cylindrical cz~ucible bodx 16 having a bottom 19, and a clousre 17 fare closing an opening at the upper end of the body 16. The crucible body 1,6 i.s provided with a heating induction coil 18 thexearound.and has a nozzle orifice 20 extending veartically through the bottom 19. The nozzle ox~.fice 20 is opposed to the opening 3 of the annular closure 2a 2. The closure 17 of the crucible 15 has a bore 21 for 20880e injecting a pressure medium such as Ar, ~2 or. like inert gas and molten metal sent foxward into the crucible therethrough. The molten metal 22 within the crucible 15 is forced through the nozzle orifice 20 and then through the opening 3 into 'the space 23 inside the cooling liquid laxer 9 by the inert gas or the like injected into the crucible through the injec -tion bore 21 undex pressure.
Disposed in the space 23 inside the cooling ZO liguid layer 9 is a jet nozzle 24 for jetting a compressed gas, such as aix or inert gas, which is used in the usual gas atomization pzocess. The nozzle Z4 is attached to the forward end of a compressed gas supply pipe 27 inserted thxough the opening 3 of the annular closure 2 and has an ori~iae which is directed toward the thin stream of molten metal 25 forced out from the nozzle orifice 20 and toward the cooling liquid layer 9.
While the outlets of the cooling liquid injection channels 5 are formed in the side surface of an upper portion of the cooling tubulax bady 1 as illustrated, th.e distance of the outlets from the thickness adjusting ring 10, if large, results in the likelihood that the liquid layer 9 will have a reduced thickness at its midportion when the cooling liquid 13 2~D~80~~
flows down at an increased velocity. It is thexe~oxe desirable that the outlets o~ the injection channels be positioned between, the upper face of the adjusting ring 10 and the midportion between the upper end of 5 the tubular body 1 and the upper face of the ring 10.
Even when the outlets are so pos~.tiot7ed, the cooling liquid is pentrifugally forced upward above the outlets, forming the same liquid layer of definite thickness as below the outlets.
The apparatus described operates in the following manriex to produce a metal powder. First, the pump 7 is operated to form a pooling liquid layer 9 on the. inner pex~.phera~. surface of the tubular body 1.
Next, the molten metal 22 within the crucible 15 is forced out dawnward thx~augh the nozzle oxific~ ~0, with a gas jetted from the jet nozzle z4 at a high speed as indicated at 26: The gas jet ~6 from the jet nozzle 24 is applied to the molten metal 25 :~ozced out from the crucible 15 in the form o~ a thin stream, dividing the molten metal 25 and sputtering the resulting molten droplets against the cooling liquid layer ~. The molten droQlets thus sputtered are xz~jected into the cooling liquid layer 9 which flows down while swirling and are rapidly cooled and solidified into metal particles. In this case, the shage of the particles ~08~Oi~
can be altered from spherx.cal to flat indefinite forms by suztably determining the distance from the location where the gas bet 26 collide with the molten metal. 2S
to the cooling liquid layer 9. Fax example, i~ the S distance to the liquid layer 9 is small, the molten droplets divided by the gas jet 26 are injected into the liquid layer ~ before a soldi~ied shell. is formed over the surface, and are divided by the liquid layer 9 again to form fine particles o~ inde,firlite shape.
l~ conversely, if the distance is sufficiently large, the sol~.di~ied shell is formed over the surfaces of the molten droplets, permitting the droplets to remain substantially spherical when injected into the cooling l9.quid, layer 9.
15 The metal powder in the cooling l.~.quid layer then flows down over the thickness adjusting zing 10 while swirling with the cooling liquid and enters the draining net 11 from the Lower-end opening o~ the Cooling tubular body 1. The cooling liquid in the net 20 is cezatri~ugally forced radially outward from the net 11, whereby the metal powder has its liqua.d content reduced by primary drain~.zxg. The me~.aJ. powder thus drained of the liquid enters the powder collecting cQnt.ainer 12. The powder is discharged from the coz~-25 tainer, futhex drained of the liquid by a centrifuge 20880e or like liquid removing device and dried by a dryer.
The cooling liquid forced our from the net 11 is returned from the collecting cover 13 to the tank 8 and recylced ~or use.
FIG. 2 shows another metal powder production apparatus embodying the invention. Throughout FzGS. 1 and 2, like parts are designated by like reference numerals.
This embodiment hag a cooling tubular body 1 which is installed with its axis inclined, and a cooling liquid injection channel 5 formed directly in the tubular body 1 which has a large wall thickness. The channel 5 has an inlet formed in the outer peripheral surface of the tubular body 1 and connected to a pump 7 by, piping. The bodx 1 has a lower-end opening which is provided with a funnel-shaped closuxe 31 fox closing the opening. The closure has a discharge pipe 33 attached to its bottom. The interior of the pipe serves as a discharge channel 32 for a cooling liquid.
~ thickness adjusting ring 10 having a tapered upper faoe is attached with bolts to the inner pe~~z.phery of a lower portion of the tubular body 1, The discharge pipe 33 so extends that an outer-end opening (outlet) thereof is positioned above a tank 8, anti is provided with a flow regulating valve 3~ at an a.z~texmedxate 20~8fl~~
portion thereof. The tank 8 has an upper opening cohich is removably provided with a net basket 35.
With the present embodiment) the cooling liquid can be discharged with the discharge channel 32 filled with the lic~ui.d by suitably adjusting the opened position of 'the flaw regulating valve? 34. This makes it possible to prevent gas from flowing out through the discharge pipe,33 and to fill the space 23 inside the cooling liquid layer' 9 with the gas of gas jet 76 from a jet nozzle 24. Accordingly, 'the oxidation of divided molten droplets Can be prevented effectively by using an inert gas or like nonoxidizing gas.
FIG. 3 shows a third embodiment o~ metal powder production apparatus, wherein a cooling tubu~.ar body 1 is formed in its inner peripheral surface With outlets of cooling liquid injection Channels 5 as arranged in a plurality of (two) stages. The number of stages of injection channels 5 and the spacing there-between with respect to the axial dizectian of the tubular body differ in accordance with the inside d~.a~tteter of the tubular body, rate of discharge of the coali.ng liquid, pressure of injection, position of lower thicl~ness adjusting ring 10, et.c. A suitable number o~ stages may be provided as approximately equidistantlx spaced apart so as to obtain a cooling l~ ~L~38'~~~~
liquid layer of substantially unifarm in side diameter.
The present embodiment has a plurality of stages of cooling l.i.quid injection channels S above the thickness adjusting ring 10. This arrangement serves to prevent the liquid layer 9 above the r~.ng 10 from decreasing in thickness owing to an increase in the downward flow velocity of the cooling liquid. The liquid layer 9 can therefore be foamed easily with a substantially uniform inside diameter and a constant swirling velocity over 3n elongated region on the inner peri-Qheral Surface of the tubular body l, hence an elongated cooling zone. As seen in the drawing, the thickness adjust~.n.g zing may be provided between the stages of injection Channels 5 adjacent to each other ayially of the tubular body as indicated at 10A, whereby the thickness and flow velocity of the layer 9 can be mare stabilized. I3owever, the codling liquid injection chan.z~e1 5 provided in a single stage in combination.
wit~Z a plurality of thickness adjusting rings is also effective for preventing the decrease in the thickness of the layer 9.
With, the third embodiment of FZG. 3, a buffer flange 28 is xemovably attached to the znner periphery of the net 11 as by bolts. The flange Z6 reduces the do~az~ward flow velocity of the Coo~.ing liquid ~ta ensure 2088~~~
drainage for a longer period of time far effective centrifugal removal o~ the liquid.
FIG. 4 shows a fourth embodiment o~ metal powder production apparatus, which has a cooling tubular body 1 installed with irs axis inclined, and two jet nozzles 24, 24 attached to compressed gas supply pipes 27, 27 for producing gas jets Z6 intersecting each other in a v-form in a space 23 inside a cooling liquid layer 9 on the inner peripheral surface o~ the body.
Each of the jet nozzles 24, 24 has an orifice which is in the form of a slit, and the gas jet 26 is in the foam oz a film having a given width. The intersecting gas jets are v-shaped in section as illustrated in the drawing. A molten metal 25 flows out from a nozzle orifice 20 of a crucible 15 downward to the region where the V-shaped gas jets intersectoand is thereby divided. The V-shaped gas jets effectively divide the molten metal, forcing the divided molten droplets ~rom the region of inter3ection into the._.innex periphery of the cooling liquid layer 9 over a specified area fox the injection of the droplets even if the molten metal 25 flows down as somewhat deflected. Incidental-ly, a jet nozzle may be used which has a nozzle orifice in the form of an inverted conical slit for forming a gas jet defining an inverted conical face, such that 1~ ~0880~~
the molten metal. is supplied to the vertex of the jet. Alternative).y, a plurality of jet nozzles each adapted to produce a lirieaz~ gas jet may, be arranged in an inverted conical form to provide an inverted conical assembly o~ linear gas jets for the molten metal to be supplied to the vertex of the assembly.
With the third and Fourth embodiments, the cooling tubular body 1 is Q.r4vided at its lower-end opening with a draining net 11, through which the gas forming the jet or jets 26 flows out. However, the lower-end opening znay be provided with the closure 31 shown in k'TG. 2 and having the discharge pipe 33. The space 23 inside the cooling lic~u~.d layer 9 cart then be readily filled with the jet-forming gas bx contr'olling 1S the flow regulating valve 34 mounted on an intermediate portion of the discharge pipe 33.
With the Foregoing embodiments, the cooling tubulat body 1 is in the form of a hollow cylindez, Y~ut is not limited to this shape. The body may, be so shaped as to have a rotationally symmetrio inner peripheral surface the diameter of which gradually decreases toward the direction of movement of the cooling lic~u~.d.
~'or example, the body may be in the form of a funnel.
In the case where the body is trumpet~shaped with a paxaboloid of revolution, a cooling liquid layer of r ' 20 ~Q~~~~4 uniform inside diameter can be formed even i~ no thickness adjusting ring is used. Further with the illustrated embodiments, the coolzng tubular body is installed with its aril positioned vertically or obliquely, whereas this position is not limitative.
The axis of the tubular body may be in any position insofar as doling water can be injected into the body at a sufficient rate so as to form a coo ing liquid layer 9 on the tubular body inner peripheral surface.
Further in the case of the illustrgted embodiments, the thickness adjusting ring 10 has a horizontal or tapered upper face, which nevertheless is not limitative, For example, the ring may have a streamlined curved face extending from the outer peripheral edge of its upper end toward the inner peripheral edge of its lower end with a gradually decreasing diameter. Although the moltem metal 22 in the crucible 15 is forced out through the nozzle ori~iGe under the pressure exerted by a pressure medium, 20 the metal 22 may be forced out (caused to flow out) from the nozzle orifice 20 under gravity acting on itself without using the pressure medium.
The powders to be produced according td the invention axe not limited to those of metals having a low melting point, such as aluminum and alloxs thereof, zl 20~8~~~~
but include those o,f metals having a high melting point, such as titanium, nickel, iron and alloys there-of, Thus the metals to be treated are not limited specifically.
FIGS. 5 and 6 show the overall construction of an examp~.e of metal powder continuous production equipznewt which includes the metal powder production apparatus already described with reference to FZG. ~.
as the first embodiment and which is adapted to ZO carry out d sequence of operations from th.e supply of molten metal. through the production of metal powder, removal. of the liquid anal drying . With. this equipment, the molten metal. supplied From a molten mcta7. cont~.nuous feeder 41 is treated bx the metal powder psoduct:ion 1S apparatus 42 already described, 3 continuous liquid removing device 43 and a continuous drxex' 44 and made into a metal. powder product. one of the other embodi-m@nts is of course usable as the metal powder produc-tiara apparatus.
20 The cnoltea metal continuous feeder ~l comprises a container 46 made of a heatTinsulating refractory material. The conts,iner 46 has a molten rttetaZ inlet 48 closable witkz a closure 47, a pipe 49 for supplying an inert gas gar like pressure medium, a 25 discharge pipe SO for molten metal 53 within tlxe zz ~~c~c~QS~
container, and a bottom cavity 52 provided with an induction heating coil 51. The molten metal 53 in the contaJ.nex 46 has its temperature controlled by the coil 51 and is fed to the crucible 15 of the apparatus 42 t.hxough the discharge pipo 50 under the pxes5uxe of the inert gas, such as argon gas, injected through the supply pipe 4.9. The di.schargo pipe 50 is heat-insulated by suitable means such as a heat-insulating layer or induction heater.
The metal powder produced by the apparatus 42 is fed to the continuous liquid removing device 43 by, way of the powder collecting container 12 along with the cooling liquid xe~naining after the primary draining by the draining net. 11, and is centrifugally acted on and thereby separated from the liquid. The continuous liquid removing device 43 aompx~.ses a rotary drum 55 ~lax'7.ng upward and having, an intermediafi.e pex'ipheral wall which is formed by a scxeez~ plate with a multipli-city of small holes. The drum 55 has a mult.~.pl~.pi.ty of projecting ribs 56 on its inner periphery for upwardly delivering the powder separated from the liquid. The rotary drum 55 is surrounded by a cooling liquid co~.l~cting cover 57, ~xom the bottom of which the cooling liquid separated o~f is collected ~.n. the tams 8.
Provided over the drum 55 is a metal powder collecting z3 cover 5$ having a discharge chute S9.
~~88~~~
The wet metal powder delivered ~rom the discharge chute 59 of the device 43 is subsequently fed to the continuous dryer 44. The dryer 44 comprises a.
drying container 62 having a porous membrane 61 with a multiplicity of p4res, feed means G3 having a rotary feeder for supplying the wet material to an upper portion of the container 62) a hot air producing device 64 for supplying hot air from the bottom o~ the container 62, and a cyclone 65 for collecting fine particles from the air discharged from the top of the container 62. A discharge pipe 66 is attached to the side wall of the container 62 at its upper to lower portions.
A fluidiaed layer 67 is formed inside the drying container 67. Tk~e wet metal powder is vigorous-1.y mixed with the hot air within the layer 67 ~or heat exchange, rapidly dried and discharged usually in the ~oxm. of an overflow from the container through the discharge pipe 66.
The molten metal continuous feeder. continu-ous liquid removing dcwice and cont~.nuous dryer for use in practicing the present inveri.tion are not limited to those described above, l~ut. suitable devices z5 commercially available are usable.
2~~$~~~.~
Metal powder preparation examples will be described below in detail.
Preparation Example 1 The production apparatus shown in ~'IG. 7 was used ~o~: preparing an aluminum alloy powder. 2'he cooling tubular bodx 1 shown was l00 mm in inside diameter D. The cooling liquid injection channel 5 had outlets positioned at the midpoint between the upper and of the body ~, and the upper end of the thick-ness adjusting ring 10. Cooling water was injected into the body at a flow rate o~ 0.3 m3/min frvm the channel outlets which were 11.5 mm in diameter'.
Consequently formed above the xi.~xg 10 was a cooling liquid layer 9 which was 55 mm tin inside diameter d, 50 mm in length h and 43 m/sec in ~low velocitx at the surface o~ tk~e water layer.
1~ molten aluminum alloy (composition: l~l-7.2 Si~1 Mg-1 Cu, in wt. ~) was prepared in the crucible 15 at 1O00~ C. The molten metal ~2 in the crucible 15 was pressurized by, supplxing argon gas thereto at 1.4 kgf/cm2, and a thin stream of molten metal 25. 2 mm in diameter, was injected from the nozzle orifice 20 0~ trie crucible 15 into a space Z3 inside the liguid layer 9. The stream of molten metal, 25 made an 2S injection angle 91 of 30 deg with a horizontal plane.
208~~~~~
An air jet 26 was ~orced out at S kgf/cmZ
from the jGt nozzle 24 with a nozzle orifice diameter of 6 mm against the molten metal 25 in the space 2~, at an angle 6~ of 4S deg between the jet 2G and a horizontal plane. When seen ~zom above as shown in FzG. 8, the angle 9~ made by the jet 26 w~.tk~ the thin stream of molten metal 25 was 45 deg as measured from the molten metal 25 in the swixling direction A of the cooling liquid layer.
The aluminum alloy powder consequently obtained had a paxt.icle sine distribution (relation between the particle size of particular particles in the powder arid tk~e oontent in wt. ~ of t~.e particles of the size based on the whole amount of the powder) iz~d~.eated at A in FIG. 9. The powder was 291.8 micro-meters in mean particle size and 0,90 g/cm3 in bulk density. The particles were found to be ~lat and indefinite in shape. This appears to indicate that the molten droplets divided by, the air jet were divided again by the cooling liquid laxer.
Fox comparison, an aluminum alloy powder was prepared undex the same conditions as above except that no air jet was applied to the molten metal. The result achieved is shown also in FzG. 9 as indicated at a. T'he powdex was 4Z0 micsometexs a.n mean particle z6 ~~880~~
size and 0.70 g/cm3 ire bulk density. '~h.is reveals that the application o~ the six jet according to the invention readily produces Finer particles.
Preparation example 2 An aluminum alloy powder having the same compositian as in Pregaratian Example 1 was prepared using the apparatus shown in FzG, 2. The cooling tubular body 1 ws.s 200 mm in inside diameter, and the axis of the body ~.~as inc:lined at an angle of 25 deg with respect to a vert~.cal. The cooling liquid injec tion channel 5 had outlets which were 11.5 mm in diameter and through which cooling water was injected, into the body at a flow rate of 0.3 m3/min. As a result, a cooling liquid layer 9, Z50 mm in inside diameter. 300 mm in length and 20 m/sec in average flow e2loc~.ty, was formed between the annular closure 2 and the Ch zckness adjusting z~~.ng 10. The flow regulating valve 3~ was adjusted to fill the discharge channel 32 wz'th the cooling' liquids A molten aluminum allay was p~e,pared at 1000o C in the crucible 15) and the molten metal 22 within the crucible was forced out in the foxzn of a .
thin stream of molten metal 25, 2 min in dzatrzeter, from the nozzle orifice 20 of the crucible 15 vextica.lly downward into a space 23 inside the lic~~.d layer 9 , z7 ~~1~~~~~~
by supplying argon gas to the crucible 15 at 1.0 kgf/cm2.
An argon gas jet 26 was applied at 10 kgf/cm2 from the jet nozzle 24 with a nozzle orifice diameter of 6 mm to the molten metal 25 in the space 23, whexeby S the molten metal 25 w'as made into particles. 7.'he angle made by the argon gas jet 26 with the molten metal 29 was 30 deg, The powder obtained was Z00 micrometers in mean particle size and 1.3 g/cm3 in bulk density.
FzG. 10 shows the reJ.a~.ion between the particle size and the cooling rate. The coolzng rate was determined from the metal structure of particles o.f the powder.
T.he draw~.ng shows that in the case of the metal powder prepared according to the invention, the cooling rate is J.04 to 105 oC/sec even when relatively laz'ge partlGlea, 100 to l000 micrometers in size, are formed.
This ir~d~.cates that the invention affords a micro;~i,ne structure. The drawing appears to indicate that the cooling rate for giving particles of 0.1 micrometer i.n size is at least l08 oC/sec.
Next, the powder was checked for gas contents, which were found to be 12 ppm of HZ and 50Q ppm o~ 02.
k'ox comparison, an aluminum alloy powder was prepared under the same conditions as above except that the flow regulat~.ng valve 34 was fuller opened so as not to 2~ 2~88~J~~
close the discharge pipe 3a with the cooling water.
The resulting powder was found to Contain 20 ppm of H2 arid 820 ppm of Oz. Th~.s indicates that the product of the irivet~tion is much lower in gas contents than the comparative example.
Preparation Fxacn~le 3 ~1n iron alloy powder was prepared undex the same conditions as in Preparation Example 2. The iron alloy had the composition of Fe-1.3 C-4 Cr-3.S Mo-10 W-3.5 V-10 Co as expressed in wt. &, and was melted at 1G00~ C.
The powder obta~.ned was 250 micrometezs ~.n mean particle si.~e. When checked for gas Contents, the powder was Eound to contain 9 ppm o~ H2, 580 ppm of 02 and 720 ppm of N2. When an ,iron alloy powdar of the same composition as above was prepared undez' the same conditions as above except that the average Flow velocity of the cooling liquid layer was S m/sec, the powdez was found to contain L5 ppm of Hz, l200 p.pm of OZ and 740 ppm of NZ. Th~.s ,reveals that as the flow velocitx of the cooling liquid layer is increased, the moJ.ten dzoplets can be mare rap~.dly separated ~r released from the vapor of the cooling l;i.quid produced the7Ceaxound So as to be ErBe from Contaminants more effectively.
~~ 20880e xNnvsTRxa.~ Anpz.zcaszz,zTx The present invention is useful fox the production o.~ metal gowdexs fox use as powdery ma.teri,als fox powder metallurgy, hat isostatic pressing, hot forging, hot ertrusion, etc., as compounding powders for synthetic resins, xubbers, metals, etc. and as magnetic powders for electromagnetic clutches or brakes.
tangentially thereof. The center line of the opening portion of the channel 5 extends obliquely downward at an angle of about 0 to about 20~ with re9pect to a plane orthogonal to the a:cis of the tubular body, Th2 liqu~.d infection tubes 4 are connected by piping to a tank 8 by way of a pump 7, which forces up the cooling liquid within the tank 8 and supplies the liquid to the inner peripheral surface of the tubular body 1 through the injection channels S of the injection tubes 4. Thus the cooling liquid layer 9 is formed on the inner peripheral surface of the tubular body 1. This layer flows down while swirling along the inner peripheral surface. The tank 8 is provided with an unillustrated a cooling liquid replenishing pipe, A oooler may be provided suitably within the tank 8 or at an inter-mediate portion of a channel for recycling the cooling liquid. Water is generally used as the cooling liquid since water is excellent in cooling ability and in~
expansive. Alternatively, oil ox like liquid for use in quenching hot metals may be used. When water is to be used, it is desired to remove dissolved oxygen from the water before use. Oxygen removing devices are readily available commercially.
A ring 10 for adjusting the thickness of the cooling liquid layer 9 is attached to an inner peri-11 ~0~80~4 pheral lower portion o~ the cooling tubular body 1 with bolts removably and replaceably. The thickness adjusting ring 10 limits the downward flow veloc~.ty of the cooling liquid, whereby, the cooling liquid layer 9 can be readily formed with an approximately uniform inside diameter at a low fJ.ow rate. The tubular body 1 has a cooling liquid discharge end, i.e., a lower-end opening, which is provided with a hollow cylindrical draining net 11. A funnel-shaped powder collecting container 12 is attached to the lower end of the net 11.
A cooling liquid collecting cover 13 is provided around and covers the net. 11. 'the collecting cover 13 is provided in its bottom with a liquid outlet 1~, which is connected to the tank 8 by piping.
The crucible 15 serving as fi.he molten metal supply means and disposed above the cooling tubuJ.ar body 1 is made of graphite, silicon nitride ox ~.~.ke refrac-tory and comprises a hollow cylindrical cz~ucible bodx 16 having a bottom 19, and a clousre 17 fare closing an opening at the upper end of the body 16. The crucible body 1,6 i.s provided with a heating induction coil 18 thexearound.and has a nozzle orifice 20 extending veartically through the bottom 19. The nozzle ox~.fice 20 is opposed to the opening 3 of the annular closure 2a 2. The closure 17 of the crucible 15 has a bore 21 for 20880e injecting a pressure medium such as Ar, ~2 or. like inert gas and molten metal sent foxward into the crucible therethrough. The molten metal 22 within the crucible 15 is forced through the nozzle orifice 20 and then through the opening 3 into 'the space 23 inside the cooling liquid laxer 9 by the inert gas or the like injected into the crucible through the injec -tion bore 21 undex pressure.
Disposed in the space 23 inside the cooling ZO liguid layer 9 is a jet nozzle 24 for jetting a compressed gas, such as aix or inert gas, which is used in the usual gas atomization pzocess. The nozzle Z4 is attached to the forward end of a compressed gas supply pipe 27 inserted thxough the opening 3 of the annular closure 2 and has an ori~iae which is directed toward the thin stream of molten metal 25 forced out from the nozzle orifice 20 and toward the cooling liquid layer 9.
While the outlets of the cooling liquid injection channels 5 are formed in the side surface of an upper portion of the cooling tubulax bady 1 as illustrated, th.e distance of the outlets from the thickness adjusting ring 10, if large, results in the likelihood that the liquid layer 9 will have a reduced thickness at its midportion when the cooling liquid 13 2~D~80~~
flows down at an increased velocity. It is thexe~oxe desirable that the outlets o~ the injection channels be positioned between, the upper face of the adjusting ring 10 and the midportion between the upper end of 5 the tubular body 1 and the upper face of the ring 10.
Even when the outlets are so pos~.tiot7ed, the cooling liquid is pentrifugally forced upward above the outlets, forming the same liquid layer of definite thickness as below the outlets.
The apparatus described operates in the following manriex to produce a metal powder. First, the pump 7 is operated to form a pooling liquid layer 9 on the. inner pex~.phera~. surface of the tubular body 1.
Next, the molten metal 22 within the crucible 15 is forced out dawnward thx~augh the nozzle oxific~ ~0, with a gas jetted from the jet nozzle z4 at a high speed as indicated at 26: The gas jet ~6 from the jet nozzle 24 is applied to the molten metal 25 :~ozced out from the crucible 15 in the form o~ a thin stream, dividing the molten metal 25 and sputtering the resulting molten droplets against the cooling liquid layer ~. The molten droQlets thus sputtered are xz~jected into the cooling liquid layer 9 which flows down while swirling and are rapidly cooled and solidified into metal particles. In this case, the shage of the particles ~08~Oi~
can be altered from spherx.cal to flat indefinite forms by suztably determining the distance from the location where the gas bet 26 collide with the molten metal. 2S
to the cooling liquid layer 9. Fax example, i~ the S distance to the liquid layer 9 is small, the molten droplets divided by the gas jet 26 are injected into the liquid layer ~ before a soldi~ied shell. is formed over the surface, and are divided by the liquid layer 9 again to form fine particles o~ inde,firlite shape.
l~ conversely, if the distance is sufficiently large, the sol~.di~ied shell is formed over the surfaces of the molten droplets, permitting the droplets to remain substantially spherical when injected into the cooling l9.quid, layer 9.
15 The metal powder in the cooling l.~.quid layer then flows down over the thickness adjusting zing 10 while swirling with the cooling liquid and enters the draining net 11 from the Lower-end opening o~ the Cooling tubular body 1. The cooling liquid in the net 20 is cezatri~ugally forced radially outward from the net 11, whereby the metal powder has its liqua.d content reduced by primary drain~.zxg. The me~.aJ. powder thus drained of the liquid enters the powder collecting cQnt.ainer 12. The powder is discharged from the coz~-25 tainer, futhex drained of the liquid by a centrifuge 20880e or like liquid removing device and dried by a dryer.
The cooling liquid forced our from the net 11 is returned from the collecting cover 13 to the tank 8 and recylced ~or use.
FIG. 2 shows another metal powder production apparatus embodying the invention. Throughout FzGS. 1 and 2, like parts are designated by like reference numerals.
This embodiment hag a cooling tubular body 1 which is installed with its axis inclined, and a cooling liquid injection channel 5 formed directly in the tubular body 1 which has a large wall thickness. The channel 5 has an inlet formed in the outer peripheral surface of the tubular body 1 and connected to a pump 7 by, piping. The bodx 1 has a lower-end opening which is provided with a funnel-shaped closuxe 31 fox closing the opening. The closure has a discharge pipe 33 attached to its bottom. The interior of the pipe serves as a discharge channel 32 for a cooling liquid.
~ thickness adjusting ring 10 having a tapered upper faoe is attached with bolts to the inner pe~~z.phery of a lower portion of the tubular body 1, The discharge pipe 33 so extends that an outer-end opening (outlet) thereof is positioned above a tank 8, anti is provided with a flow regulating valve 3~ at an a.z~texmedxate 20~8fl~~
portion thereof. The tank 8 has an upper opening cohich is removably provided with a net basket 35.
With the present embodiment) the cooling liquid can be discharged with the discharge channel 32 filled with the lic~ui.d by suitably adjusting the opened position of 'the flaw regulating valve? 34. This makes it possible to prevent gas from flowing out through the discharge pipe,33 and to fill the space 23 inside the cooling liquid layer' 9 with the gas of gas jet 76 from a jet nozzle 24. Accordingly, 'the oxidation of divided molten droplets Can be prevented effectively by using an inert gas or like nonoxidizing gas.
FIG. 3 shows a third embodiment o~ metal powder production apparatus, wherein a cooling tubu~.ar body 1 is formed in its inner peripheral surface With outlets of cooling liquid injection Channels 5 as arranged in a plurality of (two) stages. The number of stages of injection channels 5 and the spacing there-between with respect to the axial dizectian of the tubular body differ in accordance with the inside d~.a~tteter of the tubular body, rate of discharge of the coali.ng liquid, pressure of injection, position of lower thicl~ness adjusting ring 10, et.c. A suitable number o~ stages may be provided as approximately equidistantlx spaced apart so as to obtain a cooling l~ ~L~38'~~~~
liquid layer of substantially unifarm in side diameter.
The present embodiment has a plurality of stages of cooling l.i.quid injection channels S above the thickness adjusting ring 10. This arrangement serves to prevent the liquid layer 9 above the r~.ng 10 from decreasing in thickness owing to an increase in the downward flow velocity of the cooling liquid. The liquid layer 9 can therefore be foamed easily with a substantially uniform inside diameter and a constant swirling velocity over 3n elongated region on the inner peri-Qheral Surface of the tubular body l, hence an elongated cooling zone. As seen in the drawing, the thickness adjust~.n.g zing may be provided between the stages of injection Channels 5 adjacent to each other ayially of the tubular body as indicated at 10A, whereby the thickness and flow velocity of the layer 9 can be mare stabilized. I3owever, the codling liquid injection chan.z~e1 5 provided in a single stage in combination.
wit~Z a plurality of thickness adjusting rings is also effective for preventing the decrease in the thickness of the layer 9.
With, the third embodiment of FZG. 3, a buffer flange 28 is xemovably attached to the znner periphery of the net 11 as by bolts. The flange Z6 reduces the do~az~ward flow velocity of the Coo~.ing liquid ~ta ensure 2088~~~
drainage for a longer period of time far effective centrifugal removal o~ the liquid.
FIG. 4 shows a fourth embodiment o~ metal powder production apparatus, which has a cooling tubular body 1 installed with irs axis inclined, and two jet nozzles 24, 24 attached to compressed gas supply pipes 27, 27 for producing gas jets Z6 intersecting each other in a v-form in a space 23 inside a cooling liquid layer 9 on the inner peripheral surface o~ the body.
Each of the jet nozzles 24, 24 has an orifice which is in the form of a slit, and the gas jet 26 is in the foam oz a film having a given width. The intersecting gas jets are v-shaped in section as illustrated in the drawing. A molten metal 25 flows out from a nozzle orifice 20 of a crucible 15 downward to the region where the V-shaped gas jets intersectoand is thereby divided. The V-shaped gas jets effectively divide the molten metal, forcing the divided molten droplets ~rom the region of inter3ection into the._.innex periphery of the cooling liquid layer 9 over a specified area fox the injection of the droplets even if the molten metal 25 flows down as somewhat deflected. Incidental-ly, a jet nozzle may be used which has a nozzle orifice in the form of an inverted conical slit for forming a gas jet defining an inverted conical face, such that 1~ ~0880~~
the molten metal. is supplied to the vertex of the jet. Alternative).y, a plurality of jet nozzles each adapted to produce a lirieaz~ gas jet may, be arranged in an inverted conical form to provide an inverted conical assembly o~ linear gas jets for the molten metal to be supplied to the vertex of the assembly.
With the third and Fourth embodiments, the cooling tubular body 1 is Q.r4vided at its lower-end opening with a draining net 11, through which the gas forming the jet or jets 26 flows out. However, the lower-end opening znay be provided with the closure 31 shown in k'TG. 2 and having the discharge pipe 33. The space 23 inside the cooling lic~u~.d layer 9 cart then be readily filled with the jet-forming gas bx contr'olling 1S the flow regulating valve 34 mounted on an intermediate portion of the discharge pipe 33.
With the Foregoing embodiments, the cooling tubulat body 1 is in the form of a hollow cylindez, Y~ut is not limited to this shape. The body may, be so shaped as to have a rotationally symmetrio inner peripheral surface the diameter of which gradually decreases toward the direction of movement of the cooling lic~u~.d.
~'or example, the body may be in the form of a funnel.
In the case where the body is trumpet~shaped with a paxaboloid of revolution, a cooling liquid layer of r ' 20 ~Q~~~~4 uniform inside diameter can be formed even i~ no thickness adjusting ring is used. Further with the illustrated embodiments, the coolzng tubular body is installed with its aril positioned vertically or obliquely, whereas this position is not limitative.
The axis of the tubular body may be in any position insofar as doling water can be injected into the body at a sufficient rate so as to form a coo ing liquid layer 9 on the tubular body inner peripheral surface.
Further in the case of the illustrgted embodiments, the thickness adjusting ring 10 has a horizontal or tapered upper face, which nevertheless is not limitative, For example, the ring may have a streamlined curved face extending from the outer peripheral edge of its upper end toward the inner peripheral edge of its lower end with a gradually decreasing diameter. Although the moltem metal 22 in the crucible 15 is forced out through the nozzle ori~iGe under the pressure exerted by a pressure medium, 20 the metal 22 may be forced out (caused to flow out) from the nozzle orifice 20 under gravity acting on itself without using the pressure medium.
The powders to be produced according td the invention axe not limited to those of metals having a low melting point, such as aluminum and alloxs thereof, zl 20~8~~~~
but include those o,f metals having a high melting point, such as titanium, nickel, iron and alloys there-of, Thus the metals to be treated are not limited specifically.
FIGS. 5 and 6 show the overall construction of an examp~.e of metal powder continuous production equipznewt which includes the metal powder production apparatus already described with reference to FZG. ~.
as the first embodiment and which is adapted to ZO carry out d sequence of operations from th.e supply of molten metal. through the production of metal powder, removal. of the liquid anal drying . With. this equipment, the molten metal. supplied From a molten mcta7. cont~.nuous feeder 41 is treated bx the metal powder psoduct:ion 1S apparatus 42 already described, 3 continuous liquid removing device 43 and a continuous drxex' 44 and made into a metal. powder product. one of the other embodi-m@nts is of course usable as the metal powder produc-tiara apparatus.
20 The cnoltea metal continuous feeder ~l comprises a container 46 made of a heatTinsulating refractory material. The conts,iner 46 has a molten rttetaZ inlet 48 closable witkz a closure 47, a pipe 49 for supplying an inert gas gar like pressure medium, a 25 discharge pipe SO for molten metal 53 within tlxe zz ~~c~c~QS~
container, and a bottom cavity 52 provided with an induction heating coil 51. The molten metal 53 in the contaJ.nex 46 has its temperature controlled by the coil 51 and is fed to the crucible 15 of the apparatus 42 t.hxough the discharge pipo 50 under the pxes5uxe of the inert gas, such as argon gas, injected through the supply pipe 4.9. The di.schargo pipe 50 is heat-insulated by suitable means such as a heat-insulating layer or induction heater.
The metal powder produced by the apparatus 42 is fed to the continuous liquid removing device 43 by, way of the powder collecting container 12 along with the cooling liquid xe~naining after the primary draining by the draining net. 11, and is centrifugally acted on and thereby separated from the liquid. The continuous liquid removing device 43 aompx~.ses a rotary drum 55 ~lax'7.ng upward and having, an intermediafi.e pex'ipheral wall which is formed by a scxeez~ plate with a multipli-city of small holes. The drum 55 has a mult.~.pl~.pi.ty of projecting ribs 56 on its inner periphery for upwardly delivering the powder separated from the liquid. The rotary drum 55 is surrounded by a cooling liquid co~.l~cting cover 57, ~xom the bottom of which the cooling liquid separated o~f is collected ~.n. the tams 8.
Provided over the drum 55 is a metal powder collecting z3 cover 5$ having a discharge chute S9.
~~88~~~
The wet metal powder delivered ~rom the discharge chute 59 of the device 43 is subsequently fed to the continuous dryer 44. The dryer 44 comprises a.
drying container 62 having a porous membrane 61 with a multiplicity of p4res, feed means G3 having a rotary feeder for supplying the wet material to an upper portion of the container 62) a hot air producing device 64 for supplying hot air from the bottom o~ the container 62, and a cyclone 65 for collecting fine particles from the air discharged from the top of the container 62. A discharge pipe 66 is attached to the side wall of the container 62 at its upper to lower portions.
A fluidiaed layer 67 is formed inside the drying container 67. Tk~e wet metal powder is vigorous-1.y mixed with the hot air within the layer 67 ~or heat exchange, rapidly dried and discharged usually in the ~oxm. of an overflow from the container through the discharge pipe 66.
The molten metal continuous feeder. continu-ous liquid removing dcwice and cont~.nuous dryer for use in practicing the present inveri.tion are not limited to those described above, l~ut. suitable devices z5 commercially available are usable.
2~~$~~~.~
Metal powder preparation examples will be described below in detail.
Preparation Example 1 The production apparatus shown in ~'IG. 7 was used ~o~: preparing an aluminum alloy powder. 2'he cooling tubular bodx 1 shown was l00 mm in inside diameter D. The cooling liquid injection channel 5 had outlets positioned at the midpoint between the upper and of the body ~, and the upper end of the thick-ness adjusting ring 10. Cooling water was injected into the body at a flow rate o~ 0.3 m3/min frvm the channel outlets which were 11.5 mm in diameter'.
Consequently formed above the xi.~xg 10 was a cooling liquid layer 9 which was 55 mm tin inside diameter d, 50 mm in length h and 43 m/sec in ~low velocitx at the surface o~ tk~e water layer.
1~ molten aluminum alloy (composition: l~l-7.2 Si~1 Mg-1 Cu, in wt. ~) was prepared in the crucible 15 at 1O00~ C. The molten metal ~2 in the crucible 15 was pressurized by, supplxing argon gas thereto at 1.4 kgf/cm2, and a thin stream of molten metal 25. 2 mm in diameter, was injected from the nozzle orifice 20 0~ trie crucible 15 into a space Z3 inside the liguid layer 9. The stream of molten metal, 25 made an 2S injection angle 91 of 30 deg with a horizontal plane.
208~~~~~
An air jet 26 was ~orced out at S kgf/cmZ
from the jGt nozzle 24 with a nozzle orifice diameter of 6 mm against the molten metal 25 in the space 2~, at an angle 6~ of 4S deg between the jet 2G and a horizontal plane. When seen ~zom above as shown in FzG. 8, the angle 9~ made by the jet 26 w~.tk~ the thin stream of molten metal 25 was 45 deg as measured from the molten metal 25 in the swixling direction A of the cooling liquid layer.
The aluminum alloy powder consequently obtained had a paxt.icle sine distribution (relation between the particle size of particular particles in the powder arid tk~e oontent in wt. ~ of t~.e particles of the size based on the whole amount of the powder) iz~d~.eated at A in FIG. 9. The powder was 291.8 micro-meters in mean particle size and 0,90 g/cm3 in bulk density. The particles were found to be ~lat and indefinite in shape. This appears to indicate that the molten droplets divided by, the air jet were divided again by the cooling liquid laxer.
Fox comparison, an aluminum alloy powder was prepared undex the same conditions as above except that no air jet was applied to the molten metal. The result achieved is shown also in FzG. 9 as indicated at a. T'he powdex was 4Z0 micsometexs a.n mean particle z6 ~~880~~
size and 0.70 g/cm3 ire bulk density. '~h.is reveals that the application o~ the six jet according to the invention readily produces Finer particles.
Preparation example 2 An aluminum alloy powder having the same compositian as in Pregaratian Example 1 was prepared using the apparatus shown in FzG, 2. The cooling tubular body 1 ws.s 200 mm in inside diameter, and the axis of the body ~.~as inc:lined at an angle of 25 deg with respect to a vert~.cal. The cooling liquid injec tion channel 5 had outlets which were 11.5 mm in diameter and through which cooling water was injected, into the body at a flow rate of 0.3 m3/min. As a result, a cooling liquid layer 9, Z50 mm in inside diameter. 300 mm in length and 20 m/sec in average flow e2loc~.ty, was formed between the annular closure 2 and the Ch zckness adjusting z~~.ng 10. The flow regulating valve 3~ was adjusted to fill the discharge channel 32 wz'th the cooling' liquids A molten aluminum allay was p~e,pared at 1000o C in the crucible 15) and the molten metal 22 within the crucible was forced out in the foxzn of a .
thin stream of molten metal 25, 2 min in dzatrzeter, from the nozzle orifice 20 of the crucible 15 vextica.lly downward into a space 23 inside the lic~~.d layer 9 , z7 ~~1~~~~~~
by supplying argon gas to the crucible 15 at 1.0 kgf/cm2.
An argon gas jet 26 was applied at 10 kgf/cm2 from the jet nozzle 24 with a nozzle orifice diameter of 6 mm to the molten metal 25 in the space 23, whexeby S the molten metal 25 w'as made into particles. 7.'he angle made by the argon gas jet 26 with the molten metal 29 was 30 deg, The powder obtained was Z00 micrometers in mean particle size and 1.3 g/cm3 in bulk density.
FzG. 10 shows the reJ.a~.ion between the particle size and the cooling rate. The coolzng rate was determined from the metal structure of particles o.f the powder.
T.he draw~.ng shows that in the case of the metal powder prepared according to the invention, the cooling rate is J.04 to 105 oC/sec even when relatively laz'ge partlGlea, 100 to l000 micrometers in size, are formed.
This ir~d~.cates that the invention affords a micro;~i,ne structure. The drawing appears to indicate that the cooling rate for giving particles of 0.1 micrometer i.n size is at least l08 oC/sec.
Next, the powder was checked for gas contents, which were found to be 12 ppm of HZ and 50Q ppm o~ 02.
k'ox comparison, an aluminum alloy powder was prepared under the same conditions as above except that the flow regulat~.ng valve 34 was fuller opened so as not to 2~ 2~88~J~~
close the discharge pipe 3a with the cooling water.
The resulting powder was found to Contain 20 ppm of H2 arid 820 ppm of Oz. Th~.s indicates that the product of the irivet~tion is much lower in gas contents than the comparative example.
Preparation Fxacn~le 3 ~1n iron alloy powder was prepared undex the same conditions as in Preparation Example 2. The iron alloy had the composition of Fe-1.3 C-4 Cr-3.S Mo-10 W-3.5 V-10 Co as expressed in wt. &, and was melted at 1G00~ C.
The powder obta~.ned was 250 micrometezs ~.n mean particle si.~e. When checked for gas Contents, the powder was Eound to contain 9 ppm o~ H2, 580 ppm of 02 and 720 ppm of N2. When an ,iron alloy powdar of the same composition as above was prepared undez' the same conditions as above except that the average Flow velocity of the cooling liquid layer was S m/sec, the powdez was found to contain L5 ppm of Hz, l200 p.pm of OZ and 740 ppm of NZ. Th~.s ,reveals that as the flow velocitx of the cooling liquid layer is increased, the moJ.ten dzoplets can be mare rap~.dly separated ~r released from the vapor of the cooling l;i.quid produced the7Ceaxound So as to be ErBe from Contaminants more effectively.
~~ 20880e xNnvsTRxa.~ Anpz.zcaszz,zTx The present invention is useful fox the production o.~ metal gowdexs fox use as powdery ma.teri,als fox powder metallurgy, hat isostatic pressing, hot forging, hot ertrusion, etc., as compounding powders for synthetic resins, xubbers, metals, etc. and as magnetic powders for electromagnetic clutches or brakes.
Claims (16)
ORPRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of producing a metal powder, comprising the steps of providing a nonrotating fixed cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
injecting a cooling liquid generally tangentially into the nonrotating fixed cooling tubular body along an inner peripheral surface thereof with a velocity to form a cooling liquid layer moving toward a cooling liquid discharge end of the tubular body while swirling along the tubular body inner peripheral surface and leaving a liquid free central space within the tubular body;
decreasing downward flow velocity of the injected cooling liquid by providing said cooling tubular body with a narrower width at a lower portion of the tubular body than at an upper portion of the tubular body, said narrower width being provided by (a) providing a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, (b) providing the ring with an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from the inner peripheral surface, and (c) providing the ring at a location within said cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end;
supplying a molten metal to the space inside the cooling liquid layer;
applying a gas jet to the molten metal to divide the molten metal and supply the divided molten metal to the cooling liquid layer; and discharging the cooling liquid containing a metal powder solidified in the liquid layer from the cooling liquid discharge end of the tubular body to outside.
injecting a cooling liquid generally tangentially into the nonrotating fixed cooling tubular body along an inner peripheral surface thereof with a velocity to form a cooling liquid layer moving toward a cooling liquid discharge end of the tubular body while swirling along the tubular body inner peripheral surface and leaving a liquid free central space within the tubular body;
decreasing downward flow velocity of the injected cooling liquid by providing said cooling tubular body with a narrower width at a lower portion of the tubular body than at an upper portion of the tubular body, said narrower width being provided by (a) providing a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, (b) providing the ring with an inwardly extending upper surface extending inwardly from the inner peripheral surface such that the cooling liquid is forced to flow over the ring inwardly away from the inner peripheral surface, and (c) providing the ring at a location within said cooling tubular body such that the upper surface of the ring is in between the upper end and the lower end such that the cooling liquid is forced to flow over the ring prior to being discharged from the lower end;
supplying a molten metal to the space inside the cooling liquid layer;
applying a gas jet to the molten metal to divide the molten metal and supply the divided molten metal to the cooling liquid layer; and discharging the cooling liquid containing a metal powder solidified in the liquid layer from the cooling liquid discharge end of the tubular body to outside.
2. A method of producing a metal powder as defined in claim 1, wherein the step of discharging includes the cooling liquid containing the metal powder solidified in the liquid layer being discharged to outside of the tubular body through a discharge pipe attached to a closure provided at the discharge end of the tubular body while filling the pipe with the cooling liquid.
3. A method of producing a metal powder as defined in claim 1 or 2 wherein water is used as the cooling liquid, and the gas jet is formed by an inert gas.
4. A method of producing a metal powder as defined in claim 1 or 2 wherein the cooling tubular body is in the form of a hollow cylinder.
5. A method of producing a metal powder as defined in claim 1 or 2 wherein the molten metal is supplied by gravity.
6. A method of producing a metal powder as defined in claims 1 or 2 wherein the metal powder discharged along with the cooling liquid is continuously drained of the liquid and subsequently dried continuously.
7. A method of producing a metal powder as defined in claim 2, wherein gas applied from the gas jet is maintained within the space inside the cooling liquid layer by the liquid in the discharge pipe.
8. The method of producing a metal powder as defined in claim 1, wherein the step of discharging the cooling liquid includes draining the liquid through a circumferential drainage net around the periphery of the tubular body, the liquid draining therethrough by centrifugal force of the liquid.
9. A method of producing a metal powder as defined in claim 1, wherein said ring is attached in the inner peripheral surface of the cooling tubular body.
. A method of producing a metal powder as defined in claim 9, wherein said ring has a tapered upper surface.
11. An apparatus for producing a metal powder, comprising:
a nonrotating fixed cooling tubular body, said cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
a cooling liquid injection channel means for injecting a cooling liquid generally tangentially into the tubular body and creating a cooling liquid layer along an inner peripheral surface thereof ;
said cooling tubular body having a narrower width at a lower portion of the tubular body than at a level at which said cooling liquid injection channel means injects said cooling liquid;
molten metal supply means for supplying a molten metal into a space inside the cooling liquid layer formed by the cooling liquid injected from the injection channel;
gas jet injection means for producing a gas jet to divide the molten metal and supply the divided molten metal to the cooling liquid layer;
cooling liquid supply means for supplying the cooling liquid to the cooling liquid injection channel;
wherein said narrower width includes a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, said ring having an inwardly extending upper surface extending inwardly from said inner peripheral surface such that the cooling liquid is forced to flow over said ring inwardly away from said inner peripheral surface; and said ring being located within said cooling tubular body such that said upper surface of said ring is in between said upper end and said lower end such that the cooling liquid is forced to flow over said ring prior to being discharged from said lower end.
a nonrotating fixed cooling tubular body, said cooling tubular body having an upper end and a lower end through which cooling liquid is discharged;
a cooling liquid injection channel means for injecting a cooling liquid generally tangentially into the tubular body and creating a cooling liquid layer along an inner peripheral surface thereof ;
said cooling tubular body having a narrower width at a lower portion of the tubular body than at a level at which said cooling liquid injection channel means injects said cooling liquid;
molten metal supply means for supplying a molten metal into a space inside the cooling liquid layer formed by the cooling liquid injected from the injection channel;
gas jet injection means for producing a gas jet to divide the molten metal and supply the divided molten metal to the cooling liquid layer;
cooling liquid supply means for supplying the cooling liquid to the cooling liquid injection channel;
wherein said narrower width includes a ring for adjusting the thickness of the cooling liquid layer extending around the inner peripheral surface of the cooling tubular body, said ring having an inwardly extending upper surface extending inwardly from said inner peripheral surface such that the cooling liquid is forced to flow over said ring inwardly away from said inner peripheral surface; and said ring being located within said cooling tubular body such that said upper surface of said ring is in between said upper end and said lower end such that the cooling liquid is forced to flow over said ring prior to being discharged from said lower end.
12. An apparatus for producing a metal powder as defined in claim 11, wherein the tubular body has a closure attached to its cooling liquid discharge end, wherein a discharge pipe is attached to the closure for discharging the cooling liquid therethrough, and wherein a flow regulation means is provided for keeping the pipe filled with the cooling liquid.
13. An apparatus for producing a metal powder as defined in claim 11 or 12 wherein the cooling tubular body is in the form of a hollow cylinder.
14. An apparatus for producing a metal powder as defined in claim 13 , wherein said narrower width includes said ring attached to the inner peripheral surface of the cooling tubular body.
15. An apparatus for producing a metal powder as defined in claim 14 including a plurality of rings for adjusting the thickness of the layer.
16. An apparatus for producing a metal powder as defined in claim 14, wherein said ring has a tapered upper surface.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13434991 | 1991-06-05 | ||
| JP3-134349 | 1991-09-17 | ||
| JP23641491 | 1991-09-17 | ||
| JP3-236414 | 1991-09-17 | ||
| PCT/JP1992/000710 WO1992021462A1 (en) | 1991-06-05 | 1992-06-01 | Method and device for making metallic powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2088054A1 CA2088054A1 (en) | 1992-12-06 |
| CA2088054C true CA2088054C (en) | 1999-08-10 |
Family
ID=26468477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002088054A Expired - Fee Related CA2088054C (en) | 1991-06-05 | 1992-06-01 | Method of and apparatus for producing metal powder |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0543017B1 (en) |
| KR (1) | KR0174749B1 (en) |
| AU (1) | AU645908B2 (en) |
| CA (1) | CA2088054C (en) |
| DE (1) | DE69224505T2 (en) |
| WO (1) | WO1992021462A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU4883601A (en) * | 2000-04-21 | 2001-11-07 | Central Res Inst Elect | Method and apparatus for producing fine particles |
| KR100768804B1 (en) * | 2000-04-21 | 2007-10-19 | 자이단호징 덴료쿠추오켄큐쇼 | Method for producing amorphous metal, method and apparatus for producing amorphous metal fine particles, and amorphous metal fine particles |
| US7008463B2 (en) * | 2000-04-21 | 2006-03-07 | Central Research Institute Of Electric Power Industry | Method for producing amorphous metal, method and apparatus for producing amorphous metal fine particles, and amorphous metal fine particles |
| FR2814097B1 (en) * | 2000-09-21 | 2002-12-13 | Commissariat Energie Atomique | PROCESS FOR THE PREPARATION OF METAL PARTICLES OR A NUCLEAR METAL ALLOY |
| KR102193651B1 (en) * | 2019-07-26 | 2020-12-21 | 코오롱인더스트리 주식회사 | Manufacturing Apparatus for Metal Powder |
| CN111001817A (en) * | 2019-12-26 | 2020-04-14 | 中天上材增材制造有限公司 | Powder collecting tank for vacuum gas atomization powder preparation |
| CN113798502B (en) * | 2021-09-16 | 2023-07-07 | 无锡锋速钢丸有限公司 | Cooling forming device and production process of stainless steel shot |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3320338A (en) * | 1965-10-22 | 1967-05-16 | Jerome H Lemelson | Particle manufacture |
| US4405535A (en) * | 1980-06-27 | 1983-09-20 | Battelle Memorial Institute | Preparation of rapidly solidified particulates |
| JPS6144111A (en) * | 1984-08-07 | 1986-03-03 | Kawasaki Steel Corp | Apparatus for producing metallic powder |
| US4648820A (en) * | 1985-11-14 | 1987-03-10 | Dresser Industries, Inc. | Apparatus for producing rapidly quenched metal particles |
| WO1989000470A1 (en) * | 1987-07-20 | 1989-01-26 | Battelle Development Corporation | Double disintegration powder method |
| JPH01198410A (en) * | 1988-02-02 | 1989-08-10 | Furukawa Electric Co Ltd:The | Apparatus for manufacturing metal powder |
| JPH06144111A (en) * | 1992-11-14 | 1994-05-24 | Yasuo Isobe | Total resistance adjusting device for auxiliary winker of automobile |
-
1992
- 1992-06-01 EP EP92911022A patent/EP0543017B1/en not_active Expired - Lifetime
- 1992-06-01 DE DE69224505T patent/DE69224505T2/en not_active Expired - Lifetime
- 1992-06-01 CA CA002088054A patent/CA2088054C/en not_active Expired - Fee Related
- 1992-06-01 KR KR1019930700241A patent/KR0174749B1/en not_active IP Right Cessation
- 1992-06-01 WO PCT/JP1992/000710 patent/WO1992021462A1/en active IP Right Grant
- 1992-06-01 AU AU17768/92A patent/AU645908B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| EP0543017A4 (en) | 1994-01-26 |
| AU645908B2 (en) | 1994-01-27 |
| DE69224505D1 (en) | 1998-04-02 |
| CA2088054A1 (en) | 1992-12-06 |
| DE69224505T2 (en) | 1998-07-02 |
| KR0174749B1 (en) | 1999-02-18 |
| WO1992021462A1 (en) | 1992-12-10 |
| EP0543017A1 (en) | 1993-05-26 |
| EP0543017B1 (en) | 1998-02-25 |
| AU1776892A (en) | 1993-01-08 |
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