Abstract: Provided is a powder mixture for powder metallurgy that has excellent fluidity, can be ejected from a green compacting die with little force, and can suppress die galling in forming. The powder mixture comprises: a raw material powder; a copper powder; a binder; a graphite powder; and carbon black. The raw material powder contains an iron-based powder in an amount of 90 mass % or more with respect to the raw material powder. An average particle size of the graphite powder is less than 5 ?m. Additive amounts of the binder, the graphite powder, the copper powder, and the carbon black are in specific ranges. A surface of the raw material powder is coated with at least part of the binder. A surface of the binder is coated with at least part of the graphite powder, at least part of the copper powder, and at least part of the carbon black.

Abstract: A method for producing water-atomized metal powder by dividing a molten metal stream, which is falling in a vertical direction, by spraying cooling water that impinges on the molten metal stream includes a step of spraying the cooling water at a spray pressure of 10 MPa or more and a spread angle in a range of 5° to 30° from each of three or more cooling water discharge ports arranged remote from the falling molten metal stream. The droplet diameter of the cooling water: 100 ?m or less, the convergence angle: 5° to 10°, and the water/molten steel ratio: 50 or more.

Abstract: 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° C. or more, spraying primary cooling water from a plurality of directions at a convergence angle of 10° to 25°, 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° C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.

Abstract: Provided is an iron-based powder for dust core with which a dust core with low iron loss and high insulation properties can be obtained. In the iron-based powder for dust core of the present disclosure, a median particle size calculated based on cumulative volume frequency of particles of the iron-based powder for dust core is 150 ?m or less, and cumulative volume frequency of the particles with an aspect ratio of 0.70 or less is 70% or less, and a median aspect ratio calculated based on cumulative volume frequency is 0.60 or more.

Abstract: A mixed powder for powder metallurgy comprises: an iron-based powder; and a lubricant, wherein the lubricant consists of a low-melting-point lubricant having a melting point of 86° C. or less and a high-melting-point lubricant having a melting point of more than 86° C., the low-melting-point lubricant has at least one of an amide group, an ester group, an amino group, and a carboxyl group, a ratio R1 of the low-melting-point lubricant to whole of the lubricant is 5 mass % or more and less than 90 mass %, a ratio R2 of a mass of a free lubricant to a mass of a binding lubricant is 0 or more and 15 or less, and an amount R3 of the low-melting-point lubricant contained as the free lubricant is less than 0.10 parts by mass with respect to 100 parts by mass of the iron-based powder.

Abstract: Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties, and can exhibit excellent fluidity without deteriorating the ejection properties even in the case of further containing carbon black. The mixed powder for powder metallurgy contains (a) an iron-based powder and (b) a lubricant, where the lubricant (b) contains a specific aliphatic amine.

Abstract: 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.

Abstract: Provided is an alloyed steel powder for powder metallurgy which has excellent compressibility and can be used to produce a sintered body that obtains improved strength simply by sintering. The alloyed steel powder for powder metallurgy contains Cu: 1.0 mass % or more and 8.0 mass % or less, Mo: more than 0.50 mass % and 2.00 mass % or less, and at least one selected from the group consisting of V: 0.05 mass % or more and 0.50 mass % or less, Nb: 0.02 mass % or more and 0.40 mass % or less, and Ti: 0.02 mass % or more and 0.40 mass % or less, with the balance consisting of Fe and inevitable impurities.

Abstract: Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties and compressibility, and can exhibit excellent fluidity without deteriorating the ejection properties or the compressibility even in the case of further containing carbon black. The mixed powder for powder metallurgy comprising an (a) iron-based powder and a (b) lubricant, wherein the (b) lubricant is an ester of disaccharide and fatty acid represented by R—COOH, and the R is an alkyl group having 11 or more carbon atoms or an alkenyl group having 11 or more carbon atoms.

Abstract: 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.

Abstract: The powder mixture for powder metallurgy includes a raw material powder, a binder, and a graphite powder, where the raw material powder contains an iron-based powder in a content of 90 mass % or more of the raw material powder, the graphite powder has an average particle size of less than 5 ?m, a ratio in mass of the binder to the sum the raw material powder and the graphite powder is 0.10 mass % to 0.80 mass %, a ratio of mass of the graphite powder to the sum of mass of the raw material powder and mass of the graphite powder is 0.6 mass % to 1.0 mass %, surface of the raw material powder is covered with at least a part of the binder, and surface of the binder covering the surface of the raw material powder is covered with at least a part of the graphite powder.

Abstract: Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties and compressibility, and can exhibit excellent fluidity without deteriorating the ejection properties or the compressibility even in the case of further containing carbon black. The mixed powder for powder metallurgy comprising an (a) iron-based powder and a (b) lubricant, wherein the (b) lubricant is an ester of disaccharide and fatty acid represented by R—COOH, and the R is an alkyl group having 11 or more carbon atoms or an alkenyl group having 11 or more carbon atoms.

Abstract: 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° C. or more, spraying primary cooling water from a plurality of directions at a convergence angle of 10° to 25°, 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° C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.

Abstract: Provided is a powder mixture for powder metallurgy that has excellent fluidity, can be ejected from a green compacting die with little force, and can suppress die galling in forming. The powder mixture comprises: a raw material powder; a copper powder; a binder; a graphite powder; and carbon black. The raw material powder contains an iron-based powder in an amount of 90 mass % or more with respect to the raw material powder. An average particle size of the graphite powder is less than 5 ?m. Additive amounts of the binder, the graphite powder, the copper powder, and the carbon black are in specific ranges. A surface of the raw material powder is coated with at least part of the binder. A surface of the binder is coated with at least part of the graphite powder, at least part of the copper powder, and at least part of the carbon black.

Abstract: Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties, and can exhibit excellent fluidity without deteriorating the ejection properties even in the case of further containing carbon black. The mixed powder for powder metallurgy contains (a) an iron-based powder and (b) a lubricant, where the lubricant (b) contains a specific aliphatic amine.

Abstract: The powder mixture for powder metallurgy includes a raw material powder, a binder, and a graphite powder, where the raw material powder contains an iron-based powder in a content of 90 mass % or more of the raw material powder, the graphite powder has an average particle size of less than 5 ?m, a ratio in mass of the binder to the sum the raw material powder and the graphite powder is 0.10 mass % to 0.80 mass %, a ratio of mass of the graphite powder to the sum of mass of the raw material powder and mass of the graphite powder is 0.6 mass % to 1.0 mass %, surface of the raw material powder is covered with at least a part of the binder, and surface of the binder covering the surface of the raw material powder is covered with at least a part of the graphite powder.

Abstract: A mixed powder for powder metallurgy having excellent green compact strength and ejectability is provided. The mixed powder for powder metallurgy includes an iron-based powder; and a copolymerized polyamide, in an amount of 0.3 to 2.0 parts by mass per 100 parts by mass of the iron-based powder, having a melting point of 80° C. to 116° C.

Abstract: A mixed powder for powder metallurgy having excellent green compact strength and ejectability is provided. The mixed powder for powder metallurgy includes an iron-based powder; and a copolymerized polyamide, in an amount of 0.3 to 2.0 parts by mass per 100 parts by mass of the iron-based powder, having a melting point of 80° C. to 116° C.

Abstract: Provided is an alloy steel powder for powder metallurgy containing an iron-based powder as a main component that is capable of achieving both high strength and high toughness in a sintered body using the same. In the alloy steel powder, the iron-based powder contains a reduced powder, and Mo content with respect to a total amount of the alloy steel powder is 0.2 mass % to 1.5 mass %, Cu powder content with respect to a total amount of the alloy steel powder is 0.5 mass % to 4.0 mass % and graphite powder content with respect to a total amount of the alloy steel powder is 0.1 mass % to 1.0 mass %.

Abstract: A mixed powder for powder metallurgy having excellent green compact strength and ejectability is provided. The mixed powder for powder metallurgy includes an iron-based powder; and a copolymerized polyamide, in an amount of 0.3 to 2.0 parts by mass per 100 parts by mass of the iron-based powder, having a melting point of 80° C. to 120° C.