JPH0556924U - Powder manufacturing equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the amount of linked powder mixed in the flat powder and increase the yield of the flat powder. Constitution: A gas is jetted to a molten metal flowing out from a nozzle to generate droplets of the molten metal, and the metallic droplets collide with the cooling surface of a rotary cooling body 4 installed below the nozzle 2 in a vertical direction. With respect to the rotation axis, a cylindrical body having a rotation axis inclined by 30 to 70 ° is used.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a powder manufacturing apparatus, and more specifically to a powder manufacturing apparatus capable of efficiently manufacturing a single flat powder suitable as a paint pigment.

[0002]

[Prior Art]

 Flat metal powders are used as Al powders in metallic paints for automobiles and stainless powders in anticorrosion paints. These flat powders can be manufactured by a method of flattening atomized powder by a ball mill or the like or a method of utilizing intergranular corrosion of stainless powder. However, since the powders produced by these methods have many mechanical strains and strains due to corrosion, a sound powder cannot be obtained. Further, these methods require a rough crushing step and a flattening step, which requires a lot of man-hours. Therefore, there has been a demand for a method capable of directly obtaining a flat powder from a molten metal.

In Japanese Patent Laid-Open No. 60-155607, molten metal flowing out from a nozzle is subjected to ultrasonic vibration and gas is jetted at high speed to generate molten metal droplets, which are then cooled by a water-cooled rotary roll ( An apparatus for producing a metal flat powder directly from a molten metal, which comprises colliding with a single roll), is disclosed.

Further, in JP-A-1-287209 and JP-A-1-319606, a gas is injected into a molten metal flowing out from a nozzle to generate a droplet of the molten metal, and the droplet of the metal is set below the nozzle. There is disclosed a device for producing a flat metal powder which is rapidly cooled and solidified by colliding with a cooling surface of a conical or horn type rotary cooling body.

[0005]

[Problems to be solved by the device]

 In the powder manufacturing apparatus of Japanese Patent Laid-Open No. 60-155607, when the molten metal flowing out from the nozzle and made into droplets by the jet gas collides with the rotary cooling body located directly below the nozzle, the jet gas is emitted to the rotary cooling body. Since the two flows before and after the collision interfere with each other, it is not possible to stably spray the molten metal.

Further, since the rotary cooling body has a cylindrical shape and its axis is oriented in the horizontal direction, most of the metal droplets collide with the cooling surface at an angle of 90 °. At this angle, the density of the droplets per cooled area is maximized, and the powders are likely to overlap each other. As a result, the overlapping powders are less likely to separate from the cooling surface, and the flattened powders collide with another powder to easily form a combined powder. When the connected flat powder is used as a pigment for paint, for example, the laminated state of the pigment is deteriorated, which may impair the appearance and corrosion resistance of the coating film.

Further, in the conical rotary cooling body used in the powder manufacturing apparatus of JP-A-1-287209 and JP-A-1-319606, the centrifugal force for separating the flattened powder has a small upper part of the cone and a large bottom surface. In addition, there is a difference in the releasing force, and as a result, the uniformity of the shape of the flat powder is impaired and the connecting powder is likely to be formed in the upper portion.

Therefore, it is an object of the present invention to provide a powder production apparatus capable of producing a flat metal powder having a uniform shape with less generation of connecting powder as compared with the conventional apparatus.

[0009]

[Means and Actions for Solving the Problems]

 A powder manufacturing apparatus according to the present invention for solving the above problems is a rotary cooling body in which a gas is injected into a molten metal flowing out of a nozzle to generate a droplet of the molten metal, and the droplet of the metal is installed below the nozzle. In the apparatus for producing a flat metal powder that is to be rapidly cooled and solidified by colliding with the cooling surface of, the cooling body is a cylindrical rotating body having a rotation axis inclined by 30 to 70 ° with respect to the vertical direction. The feature is that the surface is cooled.

More specifically, by inclining the cylindrical rotating cooling body, the liquid droplets collide with the rotating cooling surface at an acute angle, and the flat powder easily separates from the rotating cooling body in the flight direction, that is, downward. .. Further, since the collision area of the droplets becomes large, it is possible to reduce the density of the powder and reduce the connecting powder due to the overlap. Furthermore, since the same centrifugal force acts on any part of the cooling surface, the powder releasability does not differ and the powder shape becomes uniform.

Furthermore, it is necessary to install the cylindrical rotating surface, that is, the moving cooling surface, with an inclination of 30 to 70 ° with respect to the vertical direction. If the inclination angle is less than 30 °, the metal droplets generated by gas ejection spread radially and fall, so that many droplets do not collide with the rotating cooling body or collide with the rotating body at an acute angle. As a result, the proportion of spherical particles and connected powder increases. On the other hand, when the inclination angle exceeds 70 °, the collision area on the cooling moving surface decreases, and the proportion of the connecting powder increases.

[0012]

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to FIG. Example 1 An alloy having a composition of Fe ₆₉ Cr ₈ P ₁₃ C ₁₀ (atomic%) was placed in a 3 kg crucible and melted at 1300 ° C. This molten metal 1 was flown out and dropped from a nozzle 2, and nitrogen gas was blown against the flow of this molten metal 1 from a spray nozzle 3 at a pressure of 100 kg / cm ² to form droplets 5. Rotating a Cu-made rotary cooling body 4 having a diameter of 500 mm and a width of 200 mm, which is installed at an angle of 45 ° from the vertical direction, at a peripheral speed of 130 m / s, and causing the droplet 5 to collide with the Cu-made rotary cooling body 4. Thus, flat powder 6 was obtained. As a result, a single flat powder of 20 μm or more was obtained with a yield of 90%.

Example 2 In the above-described powder manufacturing apparatus shown in FIG. 1, the installation angle of the Cu rotary cooling body 4 was changed, and the other molten metal and the spraying conditions were the same as those in Example 1 to manufacture the powder. It was. The results are shown in the table below.

A single flat powder having a vertical direction of the rotating surface of the rotary cooling body of 20 μm or more. No Angle to Yield of   1 45 ° 90% Example 2 60 ° 86% Example 3 30 ° 88% Example 4 70 ° 86% Example 5 80 ° 60% Comparative Example 6 20 ° 55% Comparative Example7 90 ° 55% Comparative example

[0015]

[Effect of the device]

 As described above, according to the present invention, a flat powder suitable for a coating pigment can be produced with a high yield.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the device of the present invention.

[Explanation of symbols]

 1 Molten Metal 2 Nozzle 3 Spray Nozzle 4 Rotating Coolant Made of Cu 5 Droplet 6 Flat Powder

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshio Harakawa 1-9-9 Yaesu Chuo-ku, Tokyo Imperial Piston Ring Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A gas is injected into a molten metal flowing out from a nozzle to generate droplets of the molten metal, and the droplets of the metal are collided with a cooling surface of a rotary cooling body installed below the nozzle to rapidly solidify. In the apparatus for producing a flat metal powder, the cooling body is a cylindrical rotating body having a rotation axis inclined by 30 to 70 ° with respect to the vertical direction, and the cylindrical surface of the cylindrical rotating body is a cooling surface. Powder manufacturing equipment.