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: 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° 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° 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° C. or less and an injection pressure of 5 MPa or more.

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.

Abstract: An iron powder for dust cores is provided which can be formed into a dust core having a high resistivity and having a low iron loss without degrading the mechanical strength. The iron powder for dust cores includes an iron powder and an oxide film on the surface thereof, wherein the oxide film is composed of a Si-based oxide in which the ratio of Si to Fe satisfies Si/Fe?0.8 on an atomic number basis.

Abstract: Since a surface of an iron powder is covered with an oxide film composed of a Si-based oxide in which the ratio of Si to Fe satisfies Si/Fe?0.8 on an atomic number basis, an iron powder for dust cores is provided which can be formed into a dust core having a high resistivity and hence having a low iron loss without degrading the mechanical strength.

Abstract: An iron-based compact having a high density and also an iron-based sintered body having a high strength and a high density are manufactured with a high productivity by pre-compacting an iron-based mixed powder prepared by mixing an iron-based metal powder and a graphite powder; pre-sintering the resulting pre-compacted iron-based mixed powder at a temperature higher than 1000° C. but not higher than 1300° C. to produce a sintered iron-based powder preform containing C: 0.10 to 0.50 mass %, O: 0.3 mass % or less, and N: 0.010 mass % or less and having a density of 7.2 Mg/m3 or more; and subjecting the sintered iron-based powder preform to high-velocity compaction at a compaction energy density of 1.8 MJ/m2 or more (1.4 MJ/m2 or more for a sintered pure-iron based powder preform).

Abstract: An alloy steel powder for powder metallurgy includes an iron-based powder containing about 0.5 mass percent or less of Mn as a prealloyed element and 0.2 to about 1.5 mass percent of Mo as a prealloyed element; and a Mo-containing alloy powder bonded on the surface of the iron-based powder by diffusion bonding. In the alloy steel powder for powder metallurgy, a Mo average content [Mo]T (mass percent) satisfies formula 0.8?[Mo]T?[Mo]P?0.05, wherein the content [Mo]P is the above prealloyed Mo content (mass percent) in the iron-based powder.

Abstract: An alloy steel powder for powder metallurgy includes an iron-based powder containing about 0.5 mass percent or less of Mn as a prealloyed element and 0.2 to about 1.5 mass percent of Mo as a prealloyed element; and a Mo-containing alloy powder bonded on the surface of the iron-based powder by diffusion bonding. In the alloy steel powder for powder metallurgy, a Mo average content [MO]T (mass percent) satisfies formula 0.8?[M]T—[Mo]P?0.05, wherein the content [Mo]P is the above prealloyed Mo content (mass percent) in the iron-based powder.

Abstract: A Mo source powder is added to and mixed with an iron-based powder containing 1.0% by mass or less of prealloyed Mn to yield a powder mixture containing 0.2 to 10.0% by mass of Mo, the resulting powder mixture is subjected to heat treatment in a reducing atmosphere to thereby yield an alloyed steel powder containing Mo as a powder partially diffused and bonded to a surface of the iron-based powder particles. The prepared alloyed steel powder for powder metallurgy has satisfactory compactability. The use of this alloyed steel powder can produce a sintered powder metal body (an intermediate material after compaction and preliminary sintering in re-compaction of sintered powder materials process) for highly strong sintered member.

Abstract: This invention provides a metal powder for powder magnetic cores, which have good insulation performance and high magnetic flux density, and which is favorable for motor cores. Ferromagnetic metal powder may be coated with a coating material and a phosphate or phosphoric acid compound containing aluminum is used for the coating material. Coating the surface of iron powder with aluminum phosphate realizes to produce high-quality powder magnetic cores that have good insulation performance and high magnetic flux density and are favorable for motor cores. Further coating the aluminum phosphate-coated metal powder with silane compound or surfactant realizes more stable compressed shaped articles of the powder. And the properties of the articles do not fluctuate while stored for, so long as they are resistant to moisture. This invention contributes to producing powder magnetic cores for motors, and to the process for powder magnetic cores, furthermore, to the related art field.

Abstract: A sintered iron-based powder metal body with lower re-compacting load and having a high density and a method of manufacturing an iron-based sintered component with fewer pores of a sharp shape and having high strength and high density.

Abstract: A high density iron based forged part such as a mechanical part is produced by a method comprising the following steps in the sequence set forth: (a) preparing iron based powder mixture containing iron based metal powder and graphite powder; (b) preliminarily compacting the iron based powder mixture to form a preliminary compact; (c) sintering the preliminary compact in a non-oxidizing atmosphere whose nitrogen partial pressure is 30 kPa or less, at a temperature of 950° C. or more and of 1300° C. or less to form a forming material; and (d) forging the forming material by closed die forging or enclosed die forging to produce a high density forged part.

Abstract: 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 &mgr;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.

Abstract: The invention provides a coating method for forming a uniform coating layer on the entirety of powder by using simple means. The method has the steps of supplying the powder into a container; rotating a stirring blade so that a rotation speed of an end portion thereof is about 1.5 m/sec or more while blowing a fluidizing gas into the powder at a velocity of about 3.0 m/sec or more from a position above the powder for stirring and fluidizing, the stirring blade being disposed at a bottom portion of the container; spraying a coating fluid onto the powder from a position thereabove; and drying the coating fluid to form a coating layer.

Abstract: A Mo source powder is added to and mixed with an iron-based powder containing 1.0% by mass or less of prealloyed Mn to yield a powder mixture containing 0.2 to 10.0% by mass of Mo, the resulting powder mixture is subjected to heat treatment in a reducing atmosphere to thereby yield an alloyed steel powder containing Mo as a powder partially diffused and bonded to a surface of the iron-based powder particles. The prepared alloyed steel powder for powder metallurgy has satisfactory compactability. The use of this alloyed steel powder can produce a sintered powder metal body (an intermediate material after compaction and preliminary sintering in re-compaction of sintered powder materials process) for highly strong sintered member.

Abstract: An sintered iron-based powder metal body with outstandingly lower re-compacting load and having a high density and a method of manufacturing an iron-based sintered component with fewer pores of a sharp shape and having high strength and high density, the method comprising mixing,

Abstract: 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 ?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.