Jfe Steel Corporation

Tokin Corporation

National Institute of Advanced Industrial Science and Technology

Jfe Precision Corporation

Takuya Takashita

Akio Kobayashi

Naomichi Nakamura

Makoto Nakaseko

Akiri Urata

Nao Nasu

Naoki Yamamoto

Shigeru Unami

Miho Chiba

Makoto Yamaki

Mineo Muraki

Masato Kuno

Yosuke Imano

Itsuya Sato

Naoto Onishi

Kimihiro Ozaki

Hoshiaki Terao

Akio Sonobe

Toshio Maetani

Toshinori Tsuda

Kohsuke Ashizuka

Raita Wada

Yu Kanamori

Koichi Okamoto

Shoichi Sato

Provided is a steel strip joining method that can appropriately evaluate risk of a fracture in a joined part and prevent a fracture more reliably. An iron-based mixed powder for powder metallurgy comprises: an iron-based alloy powder; and an alloying powder, wherein the iron-based alloy powder contains Mo: 0.2 mass % or more and 1.5 mass % or less, the alloying powder contains a graphite powder and a copper powder, a ratio of a mass of the graphite powder to a total mass of the iron-based alloy powder and the alloying powder is 0.10 mass % to 1.0 mass %, a ratio of a mass of the copper powder to the total mass of the iron-based alloy powder and the alloying powder is 0.5 mass % to 3.0 mass %, and the copper powder has an average particle size of 25 μm or less, and a specific surface area of 0.30 m/g or more.

Iron-based mixed powder for powder metallurgy and iron-based sintered body

Alloy powder includes particles. The particles include specific particles. Each of the specific particles has a surface layer on which a divided trace is formed, the divided trace being a mark at which molten alloy is divided; and the divided trace has at least a hill-like ridge aggregate structure or a combination of a crater structure and the hill-like ridge aggregate structure, the hill-like ridge aggregate structure being an aggregate of a plurality of hill-like ridges.

Alloy powder, nanocrystalline powder and magnetic core

Provided is an alloyed steel powder for powder metallurgy that has excellent compressibility and enables obtaining a sintered body having improved strength as sintered. An alloyed steel powder for powder metallurgy comprises: Cu: 2.0 mass % or more and 8.0 mass % or less; Mo: more than 0.50 mass % and 2.00 mass % or less; one or both of Mn: 0.1 mass % or more and 1.0 mass % or less and Cr: 0.3 mass % or more and 3.5 mass % or less; and a balance consisting of Fe and inevitable impurities, wherein the alloyed steel powder contains particulate oxide, and a total amount of Mn and Cr in the particulate oxide is 0.15 mass % or less with respect to 100 mass % of the alloyed steel powder, and a number ratio of particulate oxide in contact with Cu of FCC structure to the particulate oxide is 50% or more.

Alloyed steel powder for powder metallurgy, iron-based mixed powder for powder metallurgy, and sintered body

Provided is an iron-based powder for dust cores that has high apparent density and enables producing dust cores having high green density. An iron-based powder for dust cores comprises a maximum particle size of 1 mm or less, wherein a median circularity of particles constituting the iron-based powder for dust cores is 0.40 or more, and a uniformity number in Rosin-Rammler equation is 0.30 or more and 90.0 or less.

Iron-based powder for dust cores and dust core

Disclosed is an alloyed steel powder for powder metallurgy from which sintered parts that do not contain expensive Ni, or Cr or Mn susceptible to oxidation, that have excellent compressibility, and that have high strength in an as-sintered state can be obtained. The alloyed steel powder for powder metallurgy has: a chemical composition containing Cu: 1.0 mass % to 8.0 mass %, with the balance being Fe and inevitable impurities; and constituent particles in which Cu is present in an precipitated state with an average particle size of 10 nm or more.

Alloyed steel powder for powder metallurgy and iron-based mixed powder for powder metallurgy

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

Provided is an Fe-based nanocrystalline alloy powder. The Fe-based nanocrystalline alloy powder has a chemical composition, excluding inevitable impurities, represented by a composition formula of FeSiBPCuM, where the M in the composition formula is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, Mn, C, Al, S, O, and N, 79 at %≤a≤84.5 at %, 0 at %≤b<6 at %, 0 at %<c≤10 at %, 4 at %<d≤11 at %, 0.2 at %≤e≤0.53 at %, 0 at %≤f≤4 at %, a+b+c+d+e+f=100 at %, a degree of crystallinity is more than 10% by volume, and an Fe crystallite diameter of the Fe-based nanocrystalline alloy powder is 50 nm or less.

Fe-based nanocrystalline alloy powder, magnetic component, and dust core

Provided is an iron-based alloy sintered body having a tensile strength of 800 MPa or more, excellent machinability, a microstructure with an average Vickers hardness of 300 Hv or more and 900 Hv or less and a standard deviation of Vickers hardness of 200 Hv or less, and an average pore circularity of 0.30 or more.

Iron-based alloy sintered body and iron-based mixed powder for powder metallurgy

Alloy powder comprises particles. The particles include specific particles. Each of the specific particles has a surface layer on which a divided trace is formed.

This soft magnetic powder is represented by composition formula FeSiBPCuwith the exception of unavoidable impurities. In the composition formula, a, b, c, d and e satisfy 79&#x2264;a&#x2264;84.5 at %, 0&#x2264;b&#x3c;6 at %, 4&#x2264;c&#x2264;10 at %, 4&#x3c;d&#x2264;11 at %, 0.2&#x2264;e&#x3c;0.4 at %, and a+b+c+d+e=100 at %.

Soft magnetic powder, Fe-based nanocrystalline alloy powder, magnetic component and dust core

A production method for water-atomized metal powder includes: in a region in which the average temperature of a molten metal stream is higher than the melting point by 100&#xb0; C. or more, spraying primary cooling water from a plurality of directions 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 of the primary cooling water from one direction and an impact direction on the molten metal stream of the primary cooling water 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+50&#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

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.

Provided is a soft magnetic powder that can produce a dust core having excellent magnetic properties. The soft magnetic powder has a chemical composition, excluding inevitable impurities, represented by a composition formula of FeSiBPCuM, where the M is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, Mn, C, Al, S, O, and N, 79 at %&#x2264;a&#x2264;84.5 at %, 0 at %&#x2264;b&#x3c;6 at %, 0 at %&#x3c;c&#x2264;10 at %, 4 at %&#x3c;d&#x2264;11 at %, 0.2 at %&#x2264;e&#x2264;0.53 at %, 0 at %&#x2264;f&#x2264;4 at %, a+b+c+d+e+f=100 at %, a particle size is 1 mm or less, and a median of circularity of particles constituting the soft magnetic powder is 0.4 or more and 1.0 or less.

Soft magnetic powder, Fe-based nanocrystalline alloy powder, magnetic component, and dust core

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 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).

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Tokyo, Japan

Takuya Takashita