JPS6227545A - Manufacture of sintered soft-magnetic parts - Google Patents

Abstract

PURPOSE:To manufacture iron-silicon sintered soft-magnetic parts of good quality in high yield by mixing an iron powder and an ion-silicon powder each having a specific grain size, forming the resulting mixture into a green compact and sintering it. CONSTITUTION:At first, the iron powder with a grain size of -100-+325mesh and the iron-silicon powder with a grain size of 5-44mu are mixed to form a powdered raw material, in which silicon content is regulated to 10-40wt%. Then the above powdered raw material is compacted to be formed into the green compact of a prescribed shape, which is sintered. In this way, a sintered compact causing no crack initiation and suitable for soft-magnetic parts having a complicated shape, such as head cores for dot printers, can be obtained.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a method for manufacturing sintered soft magnetic components.

[Technical background of the invention and its problems]

In general, soft magnetic parts made of iron-silicon alloys are widely used, but recently, it has been considered to manufacture these iron-silicon soft magnetic parts as sintered products using powder metallurgy. .

When producing sintered soft magnetic parts of iron-silicon yarn, a method using a raw material powder made by mixing iron powder and iron-silicon alloy powder (master alloy powder), the so-called master alloy powder, is used. Consideration is being given to adopting the alloy method. Compared to the alloying method that uses iron-silicon alloy powder as the raw material powder, such a master alloy method produces softer powder, a higher compaction density when the powder is pressure-molded, and has immersed magnetic properties. This is very advantageous in manufacturing soft magnetic parts using powder metallurgy.

However, in the method of manufacturing iron-silicon yarn sintered soft magnetic parts using this master alloy method, the particle size is 1100 mesh: L (
The raw material powder is a combination of 7 tomized iron powder (mesh) and iron-silica alloy powder with a particle size of 1350 mesh.

However, according to such a method, when pressing raw material powder made by mixing iron powder and iron-silicon alloy powder having the above particle size to form a compact, the pressed fc raw material There is a problem in that large springback occurs in the powder, which tends to cause cracks in the powder, that is, the green compact, and that it is difficult to mold a normal green compact with a good yield. Therefore, it is difficult to produce high-quality iron-silicon yarn sintered soft magnetic parts with a good yield.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and provides a method for manufacturing sintered soft magnetic parts that can obtain high quality iron-silicon yarn sintered soft magnetic parts with a high yield by adopting the master alloy method. The purpose is to provide

[Summary of the invention]

In the method for manufacturing sintered soft magnetic parts of the present invention, the particle size is -100
Iron powder of to +325 mesh and particle size of 5 to 44 II
The method is characterized in that a raw material powder prepared by mixing iron-silicon alloy powder is pressed to form a green compact, and this green compact is sintered to obtain a sintered body.

That is, the inventor of the present invention focused on the fact that the springback that occurs in a green compact is affected by the particle size of the powder, and as a result of various studies, it was found that By setting the respective particle sizes to sizes within the ranges described above.

To suppress the springback that occurs in the pressurized raw material powder when press-molding a powder compact, to prevent the generation of cracks in the powder, and to press-form a normal powder compact with a high yield. It was made so that it could be done.

In the method of creating a sintered soft magnetic component according to the present invention, first, iron powder with a grain size of -100 to +325 mesh and a grain size of 5
A raw material powder is obtained by mixing with iron-silicon alloy powder of μ to 44 μ. The reason why the particle size of the iron powder is set in the above range is that powder exceeding +10100 rls is difficult to fill in a narrow part of the product shape, and +325 mesh is set to have an appropriate particle size when mixed with Fe-81 powder. This is a lick to ensure distribution. In addition, the reason why the particle size of the iron-silicon alloy powder is set within the above range is that if it exceeds 44 μm, the reactivity of F during sintering will be poor and the density will not increase.
This is because if it is less than 5 μm, it will be too fine and will be easily oxidized. Iron-silicon alloy powder, containing 10-40% silicon by weight. This is to suppress the powder size of 44μ or less to 401 or less. The proportion of iron-silicon alloy powder in the raw material powder is 10 to 40% by weight. The reason for this is that if it is less than 101, the effect of the master alloy method is small, and if it exceeds 40, it will sinter, resulting in poor homogeneity of St and poor magnetic properties.

Next, the raw material powder is pressed by a press to form a compact into a predetermined shape. During this pressure molding, the springback that occurs in the raw material powder after it is pressurized and the pneumatic press mold is pulled up is small, so no cracks occur in the pneumatic raw material powder when it is pressurized, and a normal compact is formed. can.

Next, the green compact is sintered to form a sintered body, and an iron-silicon yarn sintered soft magnetic component is manufactured.

Therefore, according to the creative method of the present invention, since the generation of cracks is prevented when the green compact is pressure-formed, the green compact can be formed with a high yield, and this green compact can be used to produce high-quality iron-silicon. Yarn sintered magnetic parts can be manufactured with high yield.

The manufacturing method of the present invention can be widely applied to manufacturing soft magnetic parts, but is particularly suitable for manufacturing soft magnetic parts with complicated shapes such as head cores for dot printers.

[Embodiments of the invention]

Next, examples of the present invention will be described.

Water atomized iron powder (particle size -100 to +3) by weight
25 mesh z) S21 iron-17% silicon alloy powder (particle size -
325 mesh) and 1 g of lubricant were mixed for 40 minutes to prepare a mixed powder (invention example powder). In addition, mixed powder (comparative example powder) was prepared by mixing 82 g of water atomized iron powder (particle size -100 mesh), 11% iron-17% silicon alloy powder (particle size, 44 μ or less), and 1 g of lubricant for 40 minutes. create. Then, each mixed powder was pressurized with a molding pressure of 6 tons/d, and the diameter was 4
Green compacts were molded into a shape of 0a+X thickness lla, and the springback of these green compacts was measured. As a result, it was found that the FiO,2Ls was 0.4% in the powder compact made of the powder of the example of the present invention and 0.4% in the compact of the powder of the comparative example, and the springback occurring in the compact was reduced by the method of the present invention. It turns out that it can be suppressed.

Furthermore, using the powder of the example of the present invention and the powder of the comparative example, the first
It has the shape shown in Figures and Figure 2 and has an outer diameter of 40 m.
When rad yoke core 1 for dot printers with 5+X inner diameter 30 m x height 115 m was pressure molded, the molding could be performed normally when using the powder of the example of the present invention, but when the powder of the comparative example was used, the adsorption in the yoke core 1 Molding could not be carried out due to cracks occurring at the base of the part.

〔Effect of the invention〕

As explained above, according to the method for manufacturing sintered soft magnetic parts of the present invention, raw material powder made of a mixture of iron powder and iron-silicon alloy powder is pressurized to a normal pressure without cracking. Powder can be molded, and therefore high-quality iron-silicon yarn sintered soft magnetic parts can be manufactured with good yield.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a front view and a sectional view showing a hard yoke core for a dot printer, which is an example of a sintered soft magnetic component. I...Head yoke core. Applicant's agent Patent attorney Takehiko Suzue Second country

Claims (2)

[Claims] (1) A raw material powder made by mixing iron powder with a particle size of -100 to +325 mesh and iron-silicon alloy powder with a particle size of 5 to 44μ is pressed to form a green compact, and this green compact is 1. A method for producing a sintered soft magnetic component, the method comprising obtaining a sintered body by sintering. (2) The method for manufacturing a sintered soft magnetic component according to claim 1, wherein the proportion of iron-silicon alloy powder in the raw material powder is 10 to 40% by weight.