JPH11302703A - Drying method of metal powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently dry even such a powder that has rather large specific gravity by housing a metal powder as the objective powder with wear-resistant spheres in a metal container having good thermal conductivity, heating the metal container while the container is being vibrated so that the spheres collide with the metal powder in the container. SOLUTION: A metal powder 4 such as a rapidly solidified metal powder is housed in a metal container with a plurality of spheres 3, and the metal container 1 is heated through the lower part by a hot plate 2. At the same time, the metal container 1 is vibrated to allow the spheres 3 to collide with the metal powder 4 in the container 1. By this method, although the wet metal powder 4 is in a state which easily causes aggregation, the spheres 3 are made to collide with the metal powder 4 to loosen by vibrating the metal container 1. As a result, the heat of the heated metal container 1 is efficiently transferred directly to the metal powder or through the spheres 3. Therefore, the drying rate of the metal powder 4 is increased and the obtd. metal powder 4 has less surface oxidation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drying a metal powder such as a rapidly solidified metal powder.

[0002]

2. Description of the Related Art For example, a cooled and solidified metal powder is obtained by a water atomization method in which a molten metal is finely divided from an orifice and brought into contact with cooling water. Therefore, it is necessary to forcibly dry after dehydration treatment.

[0003] For this reason, conventionally, there is a type in which a rapidly solidified powder that has been dehydrated is placed on a net, hot air is blown from under the net, and the rapidly solidified powder is forcibly dried while floating with the hot air (eg, JP-A-3-79705).
This has an advantage that it can be dried in a shorter time than a shelf type dryer or the like, and is suitable for drying a substance having a relatively light specific gravity.

[0004]

However, in the conventional method for drying metal powder, when a wet metal powder produced by a water atomization method or the like is to be dried, the powder having a large specific gravity cannot be dried by hot air. Difficult to float. Even if the hot air pressure is increased or the amount of hot air is increased, there is a problem that only blow-through occurs and efficient drying cannot be performed. Therefore, for example, when the iron powder is wet and agglomerated, the oxidation is promoted inside, and it is impossible to obtain a high quality powder.

The present invention has been made in view of the above-mentioned problems, and is intended to efficiently dry even a powder having a relatively high specific gravity to obtain a high-quality metal powder with little oxidation at low equipment cost.

[0006]

The technical means of the present invention for solving this technical problem is to provide a metal container 1 having good thermal conductivity together with a metal powder 4 which is a powder to be treated, and a wear resistance. In this case, the metal container 1 is heated while the metal container 1 is heated, and the metal container 1 is vibrated so that the metal particles 1 collide with the sphere 3 in the metal container 1.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a metal container which is formed in a box shape from a metal having good heat conductivity such as copper.
Reference numeral 2 denotes a hot plate, in which a vibration device is incorporated. The metal container 1 is placed and fixed on the hot plate 2, the metal container 1 is heated by the hot plate 2, and the metal container 1 is vibrated back and forth and right and left. Reference numeral 3 denotes a sphere, which is made of a material such as a metal having good thermal conductivity and excellent wear resistance. A plurality of the spheres 3 are stored in the metal container 1 together with the metal powder 4 to be processed such as a rapidly solidified metal powder.

When drying a metal powder 4 such as a rapidly solidified metal powder, as shown in FIG. 1, a metal powder to be processed is put in a metal container 1 and a plurality of spheres 3 are put in the metal container 1. Heat the metal container 1 from below (200 to 30
At the same time, the sphere 3 in the metal container 1 and the metal powder 4 collide with each other. In this case, it is preferable that the amount of the metal powder 4 stored in the metal container 1 be suppressed to １ ／ or less of the gap between the spheres 3. Further, the metal plate 1 is vigorously vibrated back and forth and left and right by the hot plate 2 so that the sphere 3 can sufficiently dance.

Then, when the metal powder 4 put in the metal container 1 is dried, the dried metal powder 4 is replaced, new untreated metal powder 4 is put together with the plurality of spheres 3, and the same drying operation is repeated. I just need. According to the above method, the wet metal powder 4 is in a state of being easily agglomerated, but by vibrating the metal container 1, the metal powder 4 is
And can be loosened. As a result, the heat of the heated metal container 1 is efficiently transmitted to the metal powder 4 directly or through the sphere 3. Therefore, the drying speed of the metal powder 4 is increased, and the metal powder 4 with less surface oxidation is obtained.

According to the experimental results, when the Fe—Si—B-based water atomized powder was dried, the metal powder 4 had an oxygen content of about 500 ppm in the conventional metal powder drying method. According to the method for drying metal powder 4 of the present invention, the oxygen content of metal powder 4 was about 100 ppm. FIG. 2 shows another embodiment, in which a band heater 5 is mounted on the outer periphery of the metal container 1, and the band heater 5 heats the metal container 1 and gives vibration to the metal container 1 to thereby allow the metal container 1 to be vibrated. The sphere 3 and the metal powder 4 collide. The other points are the same as in the above-described embodiment. As in the case of the above-described embodiment, the metal powder 4 can be loosened by the collision of the spheres 3, the drying speed of the metal powder 4 increases, and the surface oxidation A small amount of metal powder 4 is obtained.

According to the above embodiment, the metal powder 4 is dried by a batch method.
Instead of this, for example, the bottom of the metal container 1 is constituted by a net slightly finer than the sphere 3, the sphere 3 is held by this net, and the metal powder 4 is passed through the net, whereby the metal powder 4 may be dried continuously.

[0012]

According to the present invention, even a powder having a relatively heavy specific gravity can be efficiently dried to obtain a high-quality metal powder with little oxidation. In addition, the configuration of the drying equipment is very simple, and the equipment cost is low.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal container 2 Hot plate 3 Sphere 4 Metal powder 5 Band heater

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Isamu Otsuka 1-1-1, Hama, Amagasaki-shi, Hyogo Prefecture Inside Kubota R & D Laboratories Co., Ltd. (72) Inventor Yoshimasa Okuno 1-1-1, Hama, Amagasaki-shi, Hyogo Stock Company Kubota Technology Development Laboratory

Claims (1)

[Claims] 1. A metal container (1) having good heat conductivity, a metal powder (4) to be treated and a sphere (3) having excellent wear resistance are stored together with the metal container (1). A method for drying metal powder, comprising heating and vibrating the metal container (1) so that the sphere (3) in the metal container (1) and the metal powder (4) collide.