公开(公告)号：US20200316688A1

公开(公告)日：2020-10-08

申请号：US16769611

申请日：2018-12-05

Applicant: JFE Steel Corporation

Inventor： Makoto Nakaseko ,  Naomichi Nakamura ,  Akio Kobayashi ,  Takuya Takashita

IPC: B22F9/08

Abstract: [Object] Provided is a method for manufacturing atomized metal powder having a high amorphous material fraction by using a water atomizing method.[Solution] A method for manufacturing atomized metal powder in which atomized metal powder having an amorphous material fraction of 90% or more is obtained, the method including ejecting high-pressure water so as to collide with a molten metal stream flowing vertically downward, separating the molten metal stream into metal powder, and cooling the metal powder, in which the high-pressure water collides with the molten metal with a collision pressure of 20 MPa or higher, and in which a temperature of the molten metal and/or a temperature of the high-pressure water are controlled so that the high-pressure water is in a subcritical state or a supercritical state on a collision surface with the molten metal.

公开(公告)号：US10710155B2

公开(公告)日：2020-07-14

申请号：US15739839

申请日：2016-09-16

Applicant: JFE STEEL CORPORATION

Inventor： Takuya Takashita ,  Akio Kobayashi ,  Naomichi Nakamura ,  Itsuya Sato

IPC: B22F1/00 ,  C22C38/16 ,  C22C38/00 ,  B22F3/16 ,  C22C33/02 ,  C22C38/12

Abstract: Provided is a mixed powder for powder metallurgy having a chemical system not using Ni which causes non-uniform metallic microstructure in a sintered body. A mixed powder for powder metallurgy comprises: a partially diffusion alloyed steel powder in which Mo diffusionally adheres to a particle surface of an iron-based powder; a Cu powder; and a graphite powder, wherein the mixed 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 the balance consisting of Fe and inevitable impurities, and the partially diffusion alloyed steel powder has: a mean particle diameter of 30 μm to 120 μm; a specific surface area of less than 0.10 m2/g; and a circularity of particles with a diameter in a range from 50 μm to 100 μm of 0.65 or less.

公开(公告)号：US10410780B2

公开(公告)日：2019-09-10

申请号：US14764273

申请日：2014-03-18

Applicant: JFE STEEL CORPORATION

Inventor： Takuya Takashita ,  Naomichi Nakamura

IPC: H01F3/08 ,  C22C38/00 ,  H01F1/24 ,  B22F1/00 ,  H01F1/147 ,  H01F1/20

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 μm or more, 60% or more of powder with a powder particle size of 100 μm or more has a mean grain size of 80 μm 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.