JPH04141509A - Device for manufacturing gas atomized metal powder - Google Patents

Abstract

PURPOSE:To obtain the excellent quality of metal powder by bisecting the inside of an atomizing tank into a first and a second chamber at upper and lower parts and arranging gas exhausting pipes communicated with a cyclone at the flanks of both chambers. CONSTITUTION:High flowing velocity gas jet is injected to a molten metal flowing down in an atomizing tank 1 by using an atomizing device 13, and the molten metal is made to fine and also rapidly cooled to manufacture the metal powder. Then, on the way of the atomizing tank 1, a partition wall 2 is disposed and at the center part of partition wall 2, an opening part 9 is formed and the partition wall is inclined downward to the opening part. The inside of the atomizing tank 1 is bisected to the upper first chamber 3 and the lower second chamber 4 with the partition wall 2, and at the flanks of both chambers 3, 4, the gas exhausting pipes 6-1, 6-2 communicated with the cyclone 5 are disposed, respectively. By this method, the residual metallic powder in the atomizing tank after recording the metal powder is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an apparatus for producing metal powder using a gas atomization method. Specifically, the present invention relates to an apparatus for producing atomized metal powder with high quality and efficiency.

(Prior Art) According to the gas atomization method, powders such as metals, alloys, and intermetallic compounds (hereinafter, these are collectively referred to as metal powders) can be produced in large quantities. FIG. 4 shows an example of a conventional metal powder production apparatus using the gas atomization method. In the figure, 31 is an atomization tank, which is generally cylindrical and composed of one chamber. A storage container 33 having a pouring pipe 32 is provided at the top of the atomization tank 31, and a spray device 34 is provided at the bottom of the storage container 33. The molten metal 35 in the storage container 33 is supplied from the pouring pipe 32 into the atomizing tank 31, and the molten metal flowing down inside the atomizing tank 31 is filled with a high-flow rate gas that is supplied from a high-pressure cylinder 36 through the supply pipe 37. A gas jet is blown from the atomizer 34 to atomize the molten metal and rapidly cool it into powder. Most of the generated metal powder is deposited at the bottom of the atomization tank 31 (metal powder indicated by reference numeral 38), and some metal powder is rolled up above the atomization tank 31 or is deposited in the exhaust pipe 40 leading to the cyclone 39. Since the metal powder 38 deposited at the bottom of the atomization tank 31 is discharged to the outside of the atomization tank 31 through the atomization tank 31 (metal powder indicated by reference numeral 41), the metal powder 38 deposited at the bottom of the atomization tank 31 is at a high temperature, so it is cooled down to a lower temperature before being recovered.

(Problem B to be solved by the invention) In the conventional device described above, the temperature of the metal powder deposited at the bottom of the atomization tank does not decrease easily, and it takes a long time, for example, one day, for the temperature to decrease to a predetermined temperature. As a result, productivity is low.

Also, if it takes such a long time to cool the metal powder,
The metal powder reacts with gas components such as oxygen remaining in the atomization tank, producing oxides and the like on the surface of the metal powder, resulting in a decrease in quality. Such a problem is more noticeable in a metal powder manufacturing apparatus equipped with a powder recovery container at the bottom of an atomization tank than in the metal powder manufacturing apparatus shown in FIG.

In the case of metal powder production equipment equipped with a powder collection container at the bottom of the atomization tank, the metal powder deposited in the powder collection container will not come into contact with the gas medium after spraying, and the cooling of the metal powder will become even slower. .

Further, in the conventional apparatus described above, among the rolled up metal powders, those that are not discharged to the outside of the atomization tank through the exhaust pipe are deposited on the upper injection device and the like. Even after atomization, the metal powder deposited in the injection device, etc. is affected by the heat from the storage container, resulting in a slow cooling rate or becoming an annealed powder, resulting in a quality difference between the metal powder deposited at the bottom of the atomization tank and the bottom of the cyclone. There will be a difference in the amount of powder, and the powder will not be converted into a product, resulting in a lower powder recovery rate.

The object of this invention is an apparatus for producing gas atomized metal powder that has a high cooling effect, can cool the generated metal powder in a short time, and can obtain products of high quality with a high powder recovery rate. Our goal is to provide the following.

(Means for Solving the Problems) The present invention relates to the improvement of an apparatus for producing metal powder by spraying a high-velocity gas jet onto molten metal flowing down in an atomization tank, atomizing it, and rapidly cooling it. It is characterized by the following structure. WI: As shown in FIG. 1, which is a drawing of an embodiment thereof, the metal powder manufacturing apparatus of the first invention has a partition wall 2 in the middle of an atomization tank 1, and the partition wall 2 has an open center. The inside of the atomizing tank 1 is divided by this partition wall 2 into a first chamber 3 at the top and a second chamber 4 at the bottom. Exhaust pipes 6-1 and 6-2 leading to the cyclone 5 are provided respectively.

In the metal powder manufacturing apparatus of the second invention, as shown in FIG. 3 which is a drawing of an embodiment thereof, the atomizing tank 1 has a structure in which the internal cross-sectional area gradually decreases and gradually increases along the way. , has an on-off valve 7 between the gradual decrease part and the gradual increase part, and the on-off valve 7 divides the inside of the atomizing tank 1 into an upper first chamber 3 and a lower second chamber 4. An exhaust pipe 6-3 communicating with the cyclone 5 having an on-off valve 8 in the middle is provided on the side surface of the chamber 4.

The partition wall 2 in the metal powder manufacturing apparatus of the first invention may have a structure in which a shielding plate 10 is provided at the periphery of the opening 9, as shown in FIG.

(Function) In the metal powder manufacturing apparatus of the first invention, as shown in FIG. A high-velocity gas jet is sprayed from the spraying device 13, and the particles are atomized and rapidly cooled to become metal powder.
The metal powder produced in the first chamber 3 enters the second chamber 4 through the opening 9 of the partition wall 2 together with a portion of the subsequent atomizing gas. At this time, a part of the metal powder is rolled up above the atomization tank 1, but since the partition wall 2 is tilted downward, the amount of metal powder rolled up is very small, and the rolled up metal powder is Since most of the gas is sucked into the cyclone 5 through the exhaust pipe 6-1, it does not adhere to or accumulate on the spray device 13 or the like.

The metal powder entering the second chamber 4 is cooled by the atomizing gas also entering the second chamber 4. The atomized gas that has entered the second chamber 4 collides with the center of the bottom of the atomization tank 1, scatters toward the outer periphery, and collides with the inner wall of the atomization tank 1 and the lower surface of the partition wall 2, creating intense turbulence and stirring the metal powder. do. By stirring the metal powder in this manner, cooling is promoted and the temperature of the metal powder is reduced in a short time. Therefore, the metal powder is less oxidized, and the metal powder after the temperature has been lowered is collected into the powder collection container 15 by opening the on-off valve 14.

In the metal powder manufacturing apparatus of the second invention, a high-velocity gas jet is blown onto the molten metal flowing down in the first chamber 3 in the same manner as described above, and the metal powder is turned into metal powder. As shown, the metal powder generated in the first chamber 3 passes through an on-off valve 7 provided between a gradually decreasing section and a gradually increasing section of cross-sectional area, and then passes through the second chamber 3.
Enter room 4. Since the lower part of the first chamber 3 is inclined downward, the amount of metal powder that is rolled up is very small.

The metal powder entering the second chamber 4 is cooled by the atomizing gas also entering the second chamber 4. At this time, similarly to the above, the atomized gas that has entered the second chamber 4 collides with the center of the bottom of the atomization tank 1, scatters in the outer circumferential direction, and returns to the atomization tank 1.
The metal powder collides with the inner wall of the partition wall 2 and the lower surface of the partition wall 2, creating a violent turbulence that stirs the metal powder. By stirring the metal powder, cooling is promoted and the temperature of the metal powder is reduced in a short time.

After powder production, the on-off valves 7 and 8 are closed, and the metal powder is also stored with the spray medium confined in the second chamber 4, or the second chamber is separated and stored at another location.

(Example) The present invention will be described in detail below using examples shown in the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the metal powder manufacturing apparatus of the first invention of the present application.

In FIG. 1, 1 is an atomization tank, and a storage container 11 is provided at the top of the tank. The storage container 11 has a pouring pipe 16 on its lower surface, and a spraying device 13 is provided below the pouring pipe 16. An atomized gas high pressure cylinder 17 is connected to the spray device 13 via a gas supply pipe 18 .

The molten metal 12 in the storage container 11 is supplied from the pouring pipe 16 into the atomization tank 1, that is, into the first chamber 3 (to be described later), and is divided and broken by a gas jet sprayed from the spray device 13 to form fine molten metal. It is made into drops and rapidly cooled.

The atomization tank 1 is provided with a partition wall 2 in the middle, and the partition wall 2 separates the inside of the atomization tank 1 into an upper first chamber 3 and a lower second chamber 4. The partition wall 2 is installed at a sufficient distance from the spray device 13. If the distance between the partition wall 2 and the spray device 13 is too short, the droplets will collide and adhere to the partition wall before solidifying, or become flaky powder. The partition wall 2 is installed at a distance necessary for complete solidification of the droplets so that these problems do not occur. This distance is determined depending on operating conditions such as the spray equipment, spray pressure, spray medium, and type of molten metal. A metal material with a melting point between 1300 and 1500°C is sprayed using Ar gas as the spraying medium, and the spraying pressure is 60k.
When atomized with gf/c■2, 3 was released from the spray device.
If the partition walls were installed at a distance of 1 m or more, no droplets were observed to adhere to the partition walls.

As shown in FIG. 1, the partition wall 2 is open at the center and slopes downward. The metal powder generated in the first chamber 3 passes through this opening 9 into the second chamber together with a part of the atomized gas after injection.
It is introduced into chamber 4. The partition wall 2 is inclined downward at an inclination angle that prevents the generated metal powder from being rolled up upward or staying on the partition wall 2.

If the inclination angle of this partition wall 2 is too large, it will be difficult for the metal powder generated in the first chamber 3 to fall into the second chamber 4, and if it is too small, the metal powder will be easily rolled up, or the partition wall will become long, making it difficult for the metal powder generated in the first chamber 3 to fall into the second chamber 4. 4 becomes long, making the device unnecessarily large.

The optimal inclination angle of the partition wall should be determined according to the operating conditions such as the tank inner diameter, the shape and diameter of the spray stream, and the spray pressure. However, if the partition wall has a conical shape, the apex angle of the cone should be 40 to 100". If the apex angle of the cone is set to approximately 60°, the powder will fall smoothly into the second chamber while remaining on the partition wall, and the equipment will be less expensive. It doesn't get bigger.

The first chamber 3 and the second chamber 4 are provided with exhaust pipes 6-1 and 6-2 leading to the cyclone 5 on their respective sides. The atomized gas is discharged together with the gas and after cooling the metal powder is discharged from the exhaust pipe 6-2. A powder recovery container 15 is provided at the bottom of the second chamber 4 via an on-off valve 14 . The cooled metal powder is collected in this powder collection container 15.

FIG. 2 shows another structure of the partition wall.

A shielding plate 10 is provided around the opening 90 of the partition wall 2 . In the second chamber 4, the metal powder is stirred and cooled by the generated turbulence, but at this time, the agitated metal powder and the turbulence collide with the atomized gas passing through the opening 9 from the side, The flow of the atomizing gas passing through the chamber 9 may be disturbed and flow back into the first chamber. By providing a shielding plate 10 around the opening 9 of the partition wall 2, this backflow can be prevented.

FIG. 3 is a longitudinal sectional view of an atomizing tank portion showing an embodiment of the metal powder manufacturing apparatus of the second invention of the present application. The upper structure of the atomizing tank 1 is the same as that of the apparatus shown in FIG. 1 above.

The atomization tank 1 has a structure in which the internal cross-sectional area gradually decreases and gradually increases along the way. An on-off valve 7 is provided between the gradually decreasing section and the gradually increasing section. The inside of the atomization tank 1 is controlled by this opening/closing valve 7.
It is separated into a chamber 3 and a second chamber 4 at the bottom. The first chamber 3 has a length necessary and sufficient for the droplets to solidify, and the sloped surface at the bottom is sloped so that the generated metal powder will not be rolled up or accumulated on the sloped surface. It has horns.

An exhaust pipe 6-3 having an on-off valve 8 in the middle and communicating with the cyclone 5 is provided on the side surface of the second chamber 4.

The atomized gas after stirring and cooling the metal powder is discharged from this exhaust pipe 6-3.

In addition, also in the case of this device, an exhaust pipe leading to the cyclone 5 may be provided on the side surface of the first chamber 3.

Table 1 shows the metal powder manufacturing apparatus of the present invention shown in FIG. 1 and the conventional metal powder manufacturing apparatus shown in FIG.
S 5KII Molten metal with chemical composition equivalent to 10 (
This figure shows the results of manufacturing metal powder at a temperature of 1600°C. The equipment and operating conditions are as shown in Table 2.

(Effects of the Invention) As shown in Table 1, in the metal powder manufacturing apparatus of the present invention, the temperature of the generated metal powder decreases in a shorter time than in the conventional metal powder manufacturing apparatus, and the temperature of the metal powder that is rolled up during manufacturing decreases. Therefore, there is little metal powder remaining in the atomization tank after the metal powder is not recovered.Therefore, the metal powder is of excellent quality and the powder recovery rate is high.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the metal powder manufacturing apparatus of the first invention of the present application, FIG. 2 is a cross-sectional view of a partition wall provided with a shielding plate around the periphery of the opening, and FIG. A vertical cross-sectional view of an atomizing tank portion showing an embodiment of a metal powder manufacturing apparatus according to the second invention of the present application; FIG. 4 is a vertical cross-sectional view showing a conventional metal powder manufacturing apparatus;
It is. 1: Atomization tank, 2: Partition wall, 3: First chamber, 4: Second chamber, 5: Cyclone, 6-1.6-2 and 6-3:
Exhaust pipe, 7.8 and 14: Opening/closing valve, 9: Opening, 10
: shielding plate, 11: storage container, 12: molten metal, 13: spray device, 15: powder recovery container, 16: pouring pipe, 17: atomizing gas high pressure cylinder, 18: gas supply pipe.

Claims (3)

[Claims] (1) In an apparatus for producing metal powder by spraying a high-velocity gas jet onto molten metal flowing down in an atomizing tank to refine the molten metal and rapidly cool it, the atomizing tank has a partition wall in the middle. The partition wall is open at the center and slopes downward, and the inside of the atomization tank is divided by the partition wall into a first chamber at the top and a second chamber at the bottom. An apparatus for producing gas atomized metal powder, characterized in that each side of the chamber is provided with an exhaust pipe leading to a cyclone. (2) The apparatus for producing gas atomized metal powder according to claim (1), wherein a shielding plate is provided along the periphery of the opening of the partition wall. (3) In an apparatus that produces metal powder by spraying a high-velocity gas jet onto molten metal flowing down inside an atomizing tank to refine the molten metal and rapidly cool it, the atomizing tank It has a structure in which the cross-sectional area gradually decreases and gradually increases, and there is an on-off valve between the gradually decreasing section and the gradually increasing section, and the inside of the tank is divided into an upper first chamber and a lower second chamber by the on-off valve. 1. An apparatus for producing gas atomized metal powder, characterized in that an exhaust pipe leading to a cyclone having an on-off valve in the middle is provided on at least a side surface of the second chamber.