JPS6191303A - Method for producing pulverous metallic powder and liquid sprayer for producing pulverous metallic powder - Google Patents

Abstract

PURPOSE:To produce metallic powder having high quality with high efficiency and to make adjustable the grain size of the metallic powder by injecting pural pairs of water jets facing each other from the nozzle of a water block toward a downward flowing molten metal at different angles with the molten metal flow. CONSTITUTION:The molten metal is dropped from the nozzle of a vessel 1 for the molten metal and the plural water jets 41, 43 and 42, 44 spouting at the different angles with the molten flow are injected to cool quickly and scatter the molten metal, thereby forming the molten metal into a powder state. The injection speed of the water jets in this case is maintained at >=340m/sec and the apex a1 formed by the water jets 41, 43 and the apex a2 formed by the water jets 42, 44 are set at different values and are made a1>a2, by which the molten metal is stably formed to the metallic powder having the uniform grain size. The grain size adjustment of the resulted metallic powder is also made possible by changing the injection speed of the water jets 41-44.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing fine metal powder by liquid spraying and a liquid spraying apparatus for producing fine metal powder for carrying out this method. be. Currently, methods for producing metal powder include pulverizing molten metal using air, water vapor, or a water shade, water spraying, and mechanically pulverizing solid alloys. Mechanical pulverization methods and chemical reduction methods that reduce oxides with gas are known, but these methods can produce metal powders at low cost and in large quantities. The liquid spray method, which is capable of pulverizing even powder, is the most widely used method.

As mentioned above, this liquid spraying method includes methods that use gas and liquid as the spraying medium, and also uses a spraying structure to spray the gas or liquid as a jet. Various shapes such as Y-shaped and conical shapes are used.

Among these, those that use liquid (water) as the spraying medium are particularly recognized for their fine particles and irregular shapes, and are suitable for metal powders for powder metallurgy. Of these, 1 is most commonly used for construction purposes. on the other hand,
As a spraying structure, both V-shape and conical 'shape are wide (
Especially, it is easy to replace the nozzle tip, and the jet speed of the n81 body (water) is 5! V-shaped structures are mainly used because they are easy to align and require virtually no maintenance.

Furthermore, among the liquid spraying methods, a characteristic of the water spraying method is that the particle size of the product powder can be easily adjusted by changing the speed of the water jet. In particular, it is widely used. In this way, the water spray method using the V-shaped structure can easily change the water jet speed i by exchanging the nozzle tip.
However, when increasing the speed of the water jet without limit in order to make the product particle size wtm, there is a risk of accumulation of metal powder on the inner surface of the water block for the water jet due to swell of molten metal, Occurrence of blockage of nozzle tip, etc.
It may also be necessary to control the shape of the water jet,
Because it is difficult to adjust the water jet speed, the current situation is that it has not yet been implemented on a regular basis.

In addition, if an attempt is made to increase the speed of the water jet using a V-shaped spray structure, the amount of molten metal that deviates perpendicularly to the jet direction of the water jet will increase, which may conversely cause the formation of coarse particles. In addition, there are many problems such as an increase in the amount of oxygen in the powder.
.

Furthermore, with recent advances in powder metallurgy technology, a wide variety of applications have been developed, and the required particle size of powder has also increased.
In particular, there is a demand for a technology to inexpensively produce powder with a grain size of 10 μm or less, but this demand has not yet been achieved.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the liquid spraying method using a V-shaped structure, the present invention solves the above-mentioned problems without having such problems. An object of the present invention is to obtain an improved method for producing fine metal powder that can meet the demand for fine metal powder, and a liquid spraying device for producing fine metal powder for carrying out this method. This is the purpose.

In order to achieve this objective, in the method of the present invention,
From the periphery of the vertically flowing molten metal, a plurality of liquid jets arranged approximately horizontally on one circumference at certain intervals are ejected so as to intersect at a certain angle in the downward direction of the flow of the molten metal, In a liquid atomized metal powder manufacturing method in which molten metal is pulverized by these liquid jets, one of the plurality of liquid jets is
The nozzles are divided into several pairs by setting one pair of nozzles facing each other, so that the liquid jet of each village intersects the molten metal at a certain angle downward in the flowing direction, and each village The liquid jets intersect the flowing molten metal at different angles in the downward direction of the flow, and
In the apparatus of the present invention, the molten metal nozzle is placed at the bottom of the molten metal nozzle in the center of the molten metal nozzle. An even number of water blocks are arranged on one circumference having a center at The center line of each nozzle tip facing the
The vertical center lines of the molten metal nozzles of the molten metal container are arranged to intersect with each other at an angle, and this intersection angle is selected to be different for each pair of water blocks, and the lower part of the water blocks is is characterized by being provided with a discharge cylinder centered on the vertical centerline of the molten metal nozzle of the molten metal container.

X~"L"1 ・Hereinafter, the present invention will be explained based on FIGS. 1 and 2 of the accompanying drawings, which schematically show the apparatus.

Firstly, FIG. 1 shows by way of a schematic diagram an exemplary embodiment of an apparatus according to the invention, as shown in the figure, the apparatus comprises vessels 1 and 1 containing molten metal below it. It consists of a water block group 2 installed at intervals. This water block group 2 has a vertical center @ passing through the center of the molten metal nozzle 11 bored in the center of the bottom of the molten metal container 1.
A perpendicular rM to X-X is drawn on a plane, has a center above this center MX-X and has a certain radius
Four water blocks 21 placed at equal intervals on the circumference
'～2. (see cmz diagram), each water block 21-44 has the shape of a horizontal hollow hexahedron, and each water block 21-2. Each has a water diene discharging nozzle tip 3 below the side facing the molten metal nozzle side of the hexahedron. ~3. The nozzle tips 3. and 3. are exchangeably attached (number 1!u in Figure 1), and among these, the nozzle tips 3. and 33 and 3□ and 3. are paired, respectively, and a pair of opposing nozzle tips 3. and 3. Mizuje Ayumu) 4. and 43 are the vertical center line x of the molten metal nozzle 11
-1, i.e., the water generats 42 and 4. from the apex a and the other pair of opposing nozzle tips 32 and 3. intersect on the vertical center line x-x of the molten metal nozzle 11, that is, the angle formed by apex a2 is mutually different, and in the case of this embodiment, al is a2 (see Figure 1).

Although the present invention has such a configuration, the molten metal flowing vertically downward from the molten metal nozzle 11 of the molten metal container 1 flows through the water jet nozzle tips 31 to 30 of each of the water blocks 21 to 24. Water fan spouting out at high speed from 34)
41-4. However, in this case, in the present invention, the water fenestration 41.4' from the water jet nozzle tip 31 and the three apex a is , Nozzle tip for water jetting 3. and 3. Water jet from 4□, 4. Since the apex formed by a2 is larger than the apex a2, the molten metal has two layers of water (upper and lower) 4+t4s and 42
,4. This grinding action can be controlled under stable conditions and in such a way that fine grinding takes place. Moreover, in this case, each of the water jetting nozzle chips 31 to 3. Water jet from 4. ~4
By appropriately adjusting the speed of step 4, it is possible to easily obtain the desired particle size of the metal powder.

Furthermore, in the present invention, a water jet discharging nozzle tip 3. ~3. Below the molten metal flowing down from the molten metal container 1, there is a nozzle tip 31 for discharging water jet.
Water jet discharged from ~344. ~44 and a small diameter circle ff115 for receiving the mixed fluid of the crushed metal powder is arranged so that its diameter is the same as the vertical center line x-x of the molten metal nozzle 11 of the container 1. be. By installing this cylinder 5, the metal powder can be rapidly cooled, and the metal powder can be cooled down to a relatively low oxygen level, for example, a, ooo to 1
Metal powder with a high fineness of 0+0OOpp- can be obtained.

In addition, in the present invention, in order to prevent the molten metal from splashing up from the apex, which is a problem when manufacturing fine metal powder in this way, the water block 2. ~2. A low-velocity water stream is caused to flow from the upper surface of the water block 2 through appropriate means along the side facing the molten metal, thereby preventing splashing of the molten It metal. ~2. It can effectively prevent adhesion to the surface.

Note that in the present invention, each water jet discharge nozzle tip 3. ~3. The pressure of the water jets 41 to 44, for example, 50G-1,000kgf/c
m” high pressure water is used, which allows high speeds, e.g.
Water jets 41-44 of 340 transport/s can be obtained.

In this way, in the present invention, 500 kgf/em2
Since we are using water at a pressure above 340 m/s and a high velocity of over 340 m/s, initially the nozzle tip 3. -34 transformation and water blocks 21 to 2. Was Nobizumi worried?
As a result of actual operation, the shape and speed of the water jet are stable, and the nozzle tips 31-3. By replacing the
It was confirmed that any water jet rate could be obtained.

Furthermore, according to the present invention, molten metal that deviates from the V-shaped structure in the right angle direction can also be removed by the water jet discharging nozzle tips 3. installed at the top and bottom 2ff. It was confirmed that the powder was reliably crushed by -31. In addition, the swell of molten metal, which is the most important problem when increasing the speed of the water jet, can be solved by water blocks 21 to 2, as shown above. The raised molten metal powder is washed away by a low-velocity water flow flowing along the side surface of the molten metal al11, and the metal powder water blocks 21 to 2. can prevent the accumulation of water and ensure a stable water spray method. However, in this case, since the washed-off metal powder is coarse particles, it is necessary to sieve it in a post-process.

Next, the results of experiments conducted to test the effects of the present invention will be explained.

Tag 1" 1e Molten metal temperature ('C) 1,650
Same left nozzle hole diameter (-1) 3.0 Same left water pressure (
kgf/am”) 500 120
Water ff1 (I/win) 220
Same jet speed on the left (-/5ee) 340
80ut exit circle 1ii1 (ms) f, 1
I00xi 500 1i'1 ni welfare-"L -3501 (%), 90,5
20.6-5009 (%) 71・One O D (〒59O rod) (μ-) 13.5
, 72.2 (Note D- is based on laser light scattering method) Moxibustion 3! Since the present invention has the above-mentioned structure and operation, metal can be powdered by a stable high-speed water jet of ≧ stages, and the molten metal can be reduced during powdering. This is particularly useful because the splashing of the powder is dealt with by the low-velocity water flowing down from the water block, and the molten metal powder can be cooled quickly and rapidly without any negative effect on the liquid spray. It exhibits the excellent effect of being able to obtain high-quality metal fine powder with high efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic ll1WR plan view showing one embodiment of the device of the present invention, and FIG. 2 is a schematic plan view showing the arrangement of water blocks. 1... Molten metal II & container, 11... Molten metal nozzle, 2
．． -2. ...Water block: 1. □~34... Nozzle tip, L'''41°°° water noft, 5... Discharge cylinder.

Claims (1)

[Claims] 1. A plurality of liquid jets arranged on a substantially horizontal circumference at certain intervals from the periphery of vertically flowing molten metal at a certain angle downward in the flowing direction of the molten metal. In a method for producing a liquid atomized metal powder in which jets are jetted across the molten metal and the molten metal is pulverized by these liquid jets, a plurality of liquid jets are used, one of which is diametrically opposed to the other. The nozzles are divided into several pairs of nozzles, and each pair of liquid jets intersects the molten metal at a certain angle in the downward direction of the flow, and the molten metal is A method for producing fine metal powder by a liquid spraying method, characterized in that the particles intersect at different angles in the downward direction of flow. 2. The method for producing fine metal powder according to claim 1, wherein the liquid is water. 3. Two pairs of water jets are arranged at equal intervals on the circumference, and each pair of opposing water jets hits the molten metal flowing vertically,
On the other hand, below the flow direction, respectively,
3. The method for producing fine metal powder according to claim 2, wherein the metal powders intersect at different angles and therefore collide with the molten metal at two locations, upper and lower. 4. The ejection velocity of each water jet is at least about 340
Claim 2 or 3 selected to be m/s
The method for producing fine metal powder as described in . 5. Below a molten metal container having a molten metal nozzle in the center of its bottom, spaced apart from it and in a plane perpendicular to the vertical centerline of the molten metal nozzle, a container having a center on the vertical centerline of the molten metal container. Arrange an even number of water blocks around the circumference, each with a nozzle tip pointing downward relative to the vertical centerline of the molten metal nozzle in the molten metal vessel, and each diametrically opposed nozzle The center lines of the tips intersect each other at an angle with the vertical center lines of the molten metal nozzles of the molten metal container below the nozzle tip, and the angle of intersection is different for each pair of water blocks. A liquid spraying device for producing fine metal powder, characterized in that a discharge cylinder centered on the vertical center line of a molten metal nozzle of a molten metal container is provided below the water block. 6. Each water block has a horizontal substantially hollow hexahedral profile, and a nozzle tip is replaceably attached to the lower side facing the vertical center line of the molten metal nozzle of the molten metal container. A liquid spraying device for producing fine metal powder according to claim 5. 7. A low-velocity water outflow member is installed on the top surface of each water block, each of which allows water to flow down at a low velocity along a plane facing the vertical centerline of the molten metal nozzle of the molten metal container of the water block. 7. The liquid spraying apparatus for producing fine metal powder according to claim 6, which has a large number of outlet ports for producing fine metal powder. 8. Four water blocks are equally spaced on one circumference, and the nozzle tips of one pair of opposing water blocks intersect each other above the vertical centerline of the molten metal nozzle of the molten metal container. 8. A liquid spraying device for producing fine metal powder according to claim 6 or 7, wherein the angle is different from that of the other pair.