Abstract: Provided is a soft magnetic dust core having high density and favorable properties. A method of manufacturing a soft magnetic dust core includes: preparing coated powder including amorphous powder made of an Fe—B—Si—P—C—Cu-based alloy, an Fe—B—P—C—Cu-based alloy, an Fe—B—Si—P—Cu-based alloy, or an Fe—B—P—Cu-based alloy, with a first initial crystallization temperature Tx1 and a second initial crystallization temperature Tx2; and a coating formed on a surface of particles of the amorphous powder; applying a compacting pressure to the coated powder or a mixture of the coated powder and the amorphous powder at a temperature equal to or lower than Tx1?100 K; and heating to a maximum end-point temperature equal to or higher than Tx1?50 K and lower than Tx2 with the compacting pressure being applied.

Abstract: An Fe—Mo—Cu—C-based alloy steel powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities, wherein an iron-based powder has a mean particle size of 30 ?m to 120 ?m, and a Cu powder has a mean particle size of 25 ?m or less. Despite the alloy steel powder for powder metallurgy having a chemical composition not containing Ni, a part produced by sintering a press formed part of the powder and further carburizing-quenching-tempering the sintered part has mechanical properties of at least as high tensile strength, toughness, and sintered density as a Ni-added part.

Abstract: Provided is an iron powder for iron powder cores, and a method for selecting the same. The following powder is an iron powder in which orientations are measured in a cross section of a compact formed with a molding pressure of 0.98 GN/m2 by electron backscatter diffraction (EBSD) and the average of KAMs calculated using EBSD analysis software is to 3.00° or less. The Iron powder has a particle size distribution in which particles with a size of 45 ?m or less are adjusted to 10% by mass or less, in which the average hardness of powder particles is 80 HV 0.025 or less in Vickers hardness, in which the product of the number (inclusions/m2) of inclusions per unit area and the median size D50 (m) of the inclusions is 10,000 (inclusions/m) or less, and which has an apparent density of 4.0 Mg/m3 or more.

Abstract: The present invention provides iron powder for dust cores that has excellent compressibility and low iron loss after formation. In the iron powder for dust cores, Si content is 0.01 mass % or less, apparent density is 3.8 g/cm3 or more, the ratio of iron powder particles with a particle size of 45 ?m or less is 10 mass % or less, the ratio of iron powder particles with a particle size of over 180 ?m and 250 ?m or less is less than 30 mass %, the ratio of iron powder particles with a particle size of over 250 ?m is 10 mass % or less, and the Vickers hardness (test force: 0.245 N) of a powder cross-section is 80 Hv or less.

Abstract: Iron powder for dust cores that is appropriate for manufacturing a dust core with low iron loss is obtained by setting the oxygen content in the powder to be 0.05 mass % or more to 0.20 mass % or less, and in a cross-section of the powder, setting the area ratio of inclusions to the matrix phase to be 0.4% or less.

Abstract: An iron powder for dust cores has an apparent density is 3.8 g/cm3 or more, a mean particle size (D50) is 80 ?m or more, 60% or more of powder with a powder particle size of 100 ?m or more has a mean grain size of 80 ?m or more inside the powder particle, an area ratio of inclusions to a matrix phase of the powder is 0.4% or less, and a micro Vickers hardness (testing force: 0.245 N) of a powder cross-section is 90 Hv or less. It is thus possible to obtain iron powder for dust cores in order to manufacture a dust core that has low hysteresis loss even after the iron powder is formed and subjected to strain relief annealing.