Jfe Steel Corporation

Kawasaki Steel Corporation

Hyundai Motor Company

Kia Motors Corporation

Other

Toyota Jidosha Kabushiki Kaisha

National Institute of Advanced Industrial Science and Technology

Tokin Corporation

Kawasaki Steel Corporaton

Hitachi, Ltd.

Unisia Jecs Corporation

Jfe Precision Corporation

Naomichi Nakamura

Takuya Takashita

Akio Kobayashi

Satoshi Uenosono

Shigeru Unami

Masashi Fujinaga

Yukiko Ozaki

Makoto Nakaseko

Yoshiei Kato

Yasuhiko Sakaguchi

Noriyoshi Yuge

Hiroyuki Baba

Kazuhiro Hanazawa

Takashi Yoshimura

Mitsumasa Iijima

Akio Sonobe

Toshio Maetani

Fukuo Aratani

Yasuo Hatai

Shin Koizumi

Hiroyuki Anma

Masamichi Abe

Itsuya Sato

Takashi Kawano

Hak Soo Kim

Tetsuya Fujii

Tatsuhiko Hiratani

Mineo Muraki

Takeshi Hattori

Daisuke Okamoto

Kimihiro Ozaki

Akiri Urata

Masateru Ueta

Toshiya Yamaguchi

Noriko Makiishi

Eisuke Hoshina

Hoshiaki Terao

Yusuke Oishi

Kohsuke Ashizuka

Toshinori Tsuda

Raita Wada

Makoto Yamaki

Hirofumi Enokido

Shoichi Sato

Koichi Okamoto

Yu Kanamori

Hisashi Sudo

Satoshi Machida

Provided is a method of manufacturing a soft magnetic dust core. The method 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 Tand a second initial crystallization temperature T; 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 T−100 K; and heating to a maximum end-point temperature equal to or higher than T−50 K and lower than Twith the compacting pressure being applied.

Method of manufacturing soft magnetic dust core

A production method for water-atomized metal powder includes: in a region in which the average temperature of a molten metal stream having an Fe concentration of 76.0 at % or more and less than 82.9 at % is 100&#xb0; C. or more higher than the melting point, spraying primary cooling water at a convergence angle of 10&#xb0; to 25&#xb0;, where the convergence angle is an angle between an impact direction on the molten metal stream from one direction and an impact direction on the molten metal stream from any other direction; and in a region in which 0.0004 seconds or more have passed after an impact of the primary cooling water and the average temperature of metal powder is the melting point or higher and (the melting point+100&#xb0; C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.

Production method for water-atomized metal powder

The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1):0.3&#xd7;Cu %+3&#xd7;Mo %&#x2264;2.7&#x2003;&#x2003;(1).

Iron-based prealloy powder, iron-based diffusion-bonded powder, and iron-based alloy powder for powder metallurgy using the same

Provided is alloyed steel powder having excellent fluidity, formability, and compressibility without containing Ni, Cr, or Si. The alloyed steel powder includes iron-based alloy containing Mo, in which Mo content is 0.4 mass % to 1.8 mass %, a weight-based median size D50 is 40 &#x3bc;m or more, and among particles contained in the alloyed steel powder, those particles having an equivalent circular diameter of 50 &#x3bc;m to 200 &#x3bc;m have a number average of solidity of 0.70 to 0.86, the solidity being defined as (particle cross-sectional area/envelope-inside area).

Alloyed steel powder

Disclosed is a mixed powder for powder metallurgy including: (a) an iron-based powder containing Si in an amount of 0 mass % to 0.2 mass % and Mn in an amount of 0 mass % to 0.4 mass %, with the balance being Fe and inevitable impurities; and (b) an alloyed steel powder containing Mo in an amount of 0.3 mass % to 4.5 mass %, Si in an amount of 0 mass % to 0.2 mass %, and Mn in an amount of 0 mass % to 0.4 mass %, with the balance being Fe and inevitable impurities, wherein a ratio of (b) the alloyed steel powder to a total of (a) the iron-based powder and (b) the alloyed steel powder is from 50 mass % to 90 mass %, and a ratio of Mo to the total of (a) the iron-based powder and (b) the alloyed steel powder is 0.20 mass % or more and less than 2.20 mass %.

Mixed powder for powder metallurgy, sintered body, and method for producing sintered body

Disclosed is a partially diffusion-alloyed steel powder having excellent fluidity, formability, and compressibility without containing Ni, Cr, and Si. A partially diffusion-alloyed steel powder having excellent fluidity, formability, and compressibility that includes an iron-based powder and Mo diffusionally adhered to a surface of the iron-based powder, in which Mo content is 0.2 mass % to 2.0 mass %, a weight-based median diameter D50 is 40 &#x3bc;m or more, and among particles contained in the partially diffusion-alloyed steel powder, those particles having an equivalent circular diameter of 50 &#x3bc;m to 200 &#x3bc;m have a number average of solidity of 0.70 to 0.86, the solidity being defined as (particle cross-sectional area/envelope-inside area).

Partially diffusion-alloyed steel powder

An iron-based alloy powder for powder metallurgy contains 2.0 mass % to 5.0 mass % of Cu, the balance being Fe and incidental impurities. From 1/10 to 8/10 of the Cu is diffusion bonded in powder-form to the surfaces of iron powder that serves as a raw material for the iron-based alloy powder, and the remainder of the Cu is contained in this iron powder as a pre-alloy. The iron-based alloy powder has superior compressibility to conventional Cu pre-alloyed iron-based alloy powders and enables production of a high strength sinter-forged member even when sintered at a lower temperature than conventional iron-based alloy powders containing mixed Cu powder.

Iron-based alloy powder for powder metallurgy, and sinter-forged member

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 &#x3bc;m to 120 &#x3bc;m; a specific surface area of less than 0.10 m/g; and a circularity of particles with a diameter in a range from 50 &#x3bc;m to 100 &#x3bc;m of 0.65 or less.

Mixed powder for powder metallurgy, sintered body, and method of manufacturing sintered body

A method for producing a water-atomized metal powder, comprising applying water to a molten metal stream, dividing the molten metal stream into a metal powder, and cooling the metal powder, wherein the metal powder is further subjected to secondary cooling with cooling capacity having a minimum heat flux point (MHF point) higher than the surface temperature of the metal powder in addition to the cooling and the secondary cooling is performed from a temperature range where the temperature of the metal powder after the cooling is not lower than the cooling start temperature necessary for amorphization nor higher than the minimum heat flux point (MHF point).

Method for producing water-atomized metal powder

An iron powder for dust cores has an apparent density is 3.8 g/cmor more, a mean particle size (D50) is 80 &#x3bc;m or more, 60% or more of powder with a powder particle size of 100 &#x3bc;m or more has a mean grain size of 80 &#x3bc;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.

Iron powder for dust core

A water-atomized metal powder is produced by dividing a molten metal stream into a metal powder by making injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more impinge on the molten metal stream and cooling the metal powder. Cooling with injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more enables can be performed not in the film boiling region but in the transition boiling region from the beginning of cooling. A gas-atomized metal powder may also be produced by dividing a molten metal stream into a metal powder by making an inert gas impinge on the molten metal stream and cooling the metal powder with injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more.

Method of producing atomized metal powder

An Fe&#x2014;Mo&#x2014;Cu&#x2014;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 &#x3bc;m to 120 &#x3bc;m, and a Cu powder has a mean particle size of 25 &#x3bc;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.

Alloy steel powder for powder metallurgy, and sintered body

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.

Iron powder for dust core and insulation-coated iron powder for dust core

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/cmor more, the ratio of iron powder particles with a particle size of 45 &#x3bc;m or less is 10 mass % or less, the ratio of iron powder particles with a particle size of over 180 &#x3bc;m and 250 &#x3bc;m or less is less than 30 mass %, the ratio of iron powder particles with a particle size of over 250 &#x3bc;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.

Iron powder for dust cores

A highly compressible iron powder for powder metallurgy has an optimized particle size distribution. The Vickers microhardness of the particles that do not pass through the sieve having the nominal opening of 150 &#x3bc;m is controlled to be at most about 110. The iron powder is suitable for production of magnetic parts having high magnetism and mechanical parts having high mechanical strength.

Highly compressible iron powder

Growing community of inventors

Chiba, Japan

Naomichi Nakamura