Abstract: Provided is an alloy steel powder for powder metallurgy that is capable of achieving both high strength and high toughness in a sintered body using the same. An alloy steel powder for powder metallurgy of this disclosure comprises a composite alloy steel powder and graphite powder. The composite alloy steel powder has a specific surface area of 0.100 m2/g or more and Mo content in a range of 0.2 mass % to 1.5 mass %, and the graphite powder content with respect to 100 mass % of the alloy steel powder for powder metallurgy is in a range of 0.1 mass % to 1.0 mass %.

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: Flowability-improving particles are adhered to surfaces of iron powder through a binder to provide an iron-based powder for powder metallurgy which has excellent flowability and which is capable of uniformly filling a thin-walled cavity and compaction with high performance of ejection force.

Abstract: In an iron-based powder, 0.01% to 5.0% by mass of a flaky powder having an average particle size of longitudinal size of 100 or less, a thickness of 10 ?m or less, and an aspect ratio (longitudinal size-to-thickness ratio) of 5 or more with respect to the iron-based mixed powder is contained, whereby the flowability of an iron-based mixed powder is increased, the density of a green compact is increased, and ejection force is greatly reduced after compaction, thereby accomplishing an increase in product quality and a reduction in production cost.

Abstract: In an iron-based powder, 0.01% to 5.0% by mass of a flaky powder having an average particle size of longitudinal size of 100 or less, a thickness of 10 ?m or less, and an aspect ratio (longitudinal size-to-thickness ratio) of 5 or more with respect to the iron-based mixed powder is contained, whereby the flowability of an iron-based mixed powder is increased, the density of a green compact is increased, and ejection force is greatly reduced after compaction, thereby accomplishing an increase in product quality and a reduction in production cost.

Abstract: A high-strength sintered compact is produced at low cost using an alloy steel powder for powder metallurgy containing no nickel or copper by compacting the alloy steel powder for powder metallurgy or a mixed powder containing the alloy steel powder at a pressure of 700 MPa or more and sintering the compact at a temperature of 1,150° C. to 1,300° C. The alloy steel powder used contains 0.3% to 0.7% by mass of chromium, 0.1% to 0.5% by mass of manganese, 0.1% to 0.5% by mass of molybdenum, and 0.25% to 0.5% by mass of oxygen, the balance being iron and incidental impurities.

Abstract: Flowability-improving particles containing 50 to 100% by mass of carbon black are adhered to surfaces of iron powder through a binder to provide an iron-based powder for powder metallurgy which has excellent flowability and which is capable of uniformly filling a thin-walled cavity, compaction with high ejection force, and maintaining sufficient strength of a sintered body in subsequent sintering.

Abstract: Flowability-improving particles are adhered to surfaces of iron powder through a binder to provide an iron-based powder for powder metallurgy which has excellent flowability and which is capable of uniformly filling a thin-walled cavity and compaction with high performance of ejection force.

Abstract: Flowability-improving particles containing 50 to 100% by mass of carbon black are adhered to surfaces of iron powder through a binder to provide an iron-based powder for powder metallurgy which has excellent flowability and which is capable of uniformly filling a thin-walled cavity, compaction with high ejection force, and maintaining sufficient strength of a sintered body in subsequent sintering.

Abstract: An iron-based powder mixture for powder metallurgy is provided, in which iron-based powder is blended with at least one selected from talc and steatite, and preferably further blended with metallic soap, thereby when a compacted body is sintered, furnace environment is not adversely affected, and excellent compaction performance is achieved even in a low temperature range of less than 100° C., and more preferably, an obtained sintered body has excellent machining performance.

Abstract: Mo of 0.05 to 1.0% by mass is adhered to the surfaces of an iron-based powder containing Mn of 0.5% by mass or less and Mo of 0.2 to 1.5% by mass as prealloyed elements by diffusion bonding, whereby an alloy steel powder is formed. Furthermore, a Ni powder of 0.2 to 5% by mass and/or a Cu powder of 0.2 to 3% by mass are added to the alloy steel powder, whereby a mixed powder for powder metallurgy is formed. The mixed powder for powder metallurgy according to the present invention enables production of sintered bodies having high density as well as superior tensile strength and rotating bending fatigue strength.

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: Mo of 0.05 to 1.0% by mass is adhered to the surfaces of an iron-based powder containing Mn of 0.5% by mass or less and Mo of 0.2 to 1.5% by mass as prealloyed elements by diffusion bonding, whereby an alloy steel powder is formed. Furthermore, a Ni powder of 0.2 to 5% by mass and/or a Cu powder of 0.2 to 3% by mass are added to the alloy steel powder, whereby a mixed powder for powder metallurgy is formed. The mixed powder for powder metallurgy according to the present invention enables production of sintered bodies having high density as well as superior tensile strength and rotating bending fatigue strength.

Abstract: In a preliminary molding step 1, a metallic powder mixture 7 obtained by blending an iron-based metal powder 7a with graphite 7b such that the graphite is present in an amount of preferably not less than 0.1% by weight, more preferably not less than 0.3% by weight, is compacted into a preform 8 having a density of not less than 7.3 g/cm3. In a provisional sintering step 2, the preform 8 is provisionally sintered at a predetermined temperature to form a metallic powder-molded body 9 having a structure in which the graphite remains along a grain boundary of the metal powder. In a re-compaction step 3, the metallic powder-molded body 9 is re-compacted into a re-compacted body 10. In a re-sintering step 4, the re-compacted body 10 is re-sintered to obtain a sintered body 11. In a heat treatment step 5, the sintered body 11 is heat-treated to obtain a heat-treated sintered body 11.

Abstract: A manufacturing method for high-density iron-based powder compacts is disclosed. The temperature of the die is adjusted at ordinary temperature or at a predetermined temperature by preheating. A lubricant for die lubrication prepared by mixing at least two different lubricants having melting points higher than a predetermined temperature of the compaction pressure is sprayed at the upper part of the die and is introduced into the die and adhered by electrification to the surface of the die. The resulting die is filled with an iron-based mixed powder including a lubricant and molding is performed at ordinary temperature or at a temperature raised by heating.

Abstract: The surface of the body of powder additive for use in powder metallurgy is coated with an organic binder, thereby obtaining powder additive to cause adhesion of the powder additive to the surface of iron-based powder by the organic binder, thereby providing a powder additive with no segregation of components and excellent flowability and compression, and an iron-based powder mixture manufactured by mixing the powder additive and 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 magnetite-iron based composite powder includes magnetite with a ratio of X-ray diffraction intensity to that of &agr;-Fe of about 0.001 to about 50 and has an average primary particle size of about 0.1 to about 10 &mgr;m. The composite powder can highly dehalogenate organic halogen compounds and exhibits satisfactory absorption power of high frequency electromagnetic waves after molding. An ultrafine nonferrous inorganic compound powder may adhere to the surface of the composite powder, or at least the composite powder may adhere to the surfaces of small particles of a nonferrous inorganic compound to thereby yield a composite powder composition. The composite powder can be produced by partial reduction of a material powder containing a hematite based powder or by complete reduction and subsequent partial oxidation of the material powder.

Abstract: A magnetite-iron based composite powder includes magnetite with a ratio of X-ray diffraction intensity to that of &agr;-Fe of about 0.001 to about 50 and has an average primary particle size of about 0.1 to about 10 &mgr;m. The composite powder can highly dehalogenate organic halogen compounds and exhibits satisfactory absorption power of high frequency electromagnetic waves after molding. An ultrafine nonferrous inorganic compound powder may adhere to the surface of the composite powder, or at least the composite powder may adhere to the surfaces of small particles of a nonferrous inorganic compound to thereby yield a composite powder composition. The composite powder can be produced by partial reduction of a material powder containing a hematite based powder or by complete reduction and subsequent partial oxidation of the material powder.

Abstract: A sintered body is produced by preparing a metal powder mixture, compacting the metal powder mixture to provide a green compact and then sintering the green compact. The metal powder mixture includes a fine metal powder having a particle size of 75 &mgr;m or smaller, a graphite powder in an amount of 0.1 to 1.0% by mass and a powder lubricant in an amount of 0.05 to 0.80% by mass based on a total mass of the metal powder mixture.