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: 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: 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: 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: On the basis of mass percentage of a mixture, 1-5% of Ni powder, 0.5-3% of Cu powder, and 0.2-0.9% of graphite powder are mixed into an alloy steel powder containing 0.5-3 mass % of prealloyed Ni, more than 0.7 to 4 mass % of prealloyed Mo, and the balance being Fe and unavoidable impurities. The alloy steel powder may contain 0.2-0.7 mass % of prealloyed Cu in addition to Ni and Mo.

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: In order to improve machinability of a sintered compact, a phosphate compound of an alkali earth metal (calcium phosphate compound or the like) is mixed with an iron-based powder, or an alkali earth metal fluoride (calcium fluoride, or the like) is further mixed with the iron-based powder. Alternatively, the alkali earth metal fluoride, together with a graphite powder, is preferably fixed to recesses of 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: 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 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 method for manufacturing sponge iron includes heating iron oxide together with a solid reducing agent to reduce the iron oxide into sponge iron, wherein the iron oxide includes a mixture of powdered hematite and powdered iron ore or a mixture of powdered hematite and powdered mill scale, the powdered hematite has a specific surface area of 2.0 m2/g or more, and the content of the powdered hematite is 5-45% by mass with respect to the total quantity of iron oxide.

Abstract: An iron-based powder including a heat-resistant insulate coating and a powder core are suggested. A paint containing silicone resin and pigment is added to a raw material powder primarily containing a ferromagnetic metal, especially, iron, agitation and mixing are performed and, thereafter, a drying treatment is performed so as to form a coating containing silicone resin and pigment on the surface of the iron-based powder. The ratio of the silicone resin content to the pigment content in the coating is preferably 0.01 or more, but less than 4.0 on a mass basis. The pigment is preferably at least one selected from the group consisting of metal oxides, metal nitrides, metal carbides, minerals, and glass. The paint may be sprayed to the iron-based powder in a fluidized state. A coating containing at least one of Si compounds, Ti compounds, Zr compounds, P compounds, and Cr compounds may be formed as a lower layer of the aforementioned coating.

Abstract: In order to improve machinability of a sintered compact, a phosphate compound of an alkali earth metal (calcium phosphate compound or the like) is mixed with an iron-based powder, or an alkali earth metal fluoride (calcium fluoride, or the like) is further mixed with the iron-based powder. Alternatively, the alkali earth metal fluoride, together with a graphite powder, is preferably fixed to recesses of 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: An iron-based mixed powder for use in powder metallurgy and excellent in die filling property and compressibility and without segregation, includes an iron-based powder in which alloying powder(s) is adhered to the surface by a binder and, further, a free lubricant. The iron-based powder includes a mixed iron powder of atomized iron powder and reduced iron powder.

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, an iron-based metal powder containing at most about 0.05% of carbon, at most about 0.3% of oxygen, at most about 0.010% of nitrogen, with at least about 0.03% and at most about 0.5% of graphite powder and a lubricant, preliminarily compacting the mixture into a preform, the density of which is about 7.3 Mg/m3 or more, and preliminarily sintering the preform in a non-oxidizing atmosphere in which a partial pressure of nitrogen is about 30 kPa or less at a temperature of about 1000° C. or higher and about 1300° C. or lower, thereby forming a sintered iron-based powder metal body with outstandingly lower re-compacting load and having high deformability, the density of which is about 7.

Abstract: A process for producing an iron-based powder composition for powder metallurgy having excellent flowability at room temperature and a warm compaction temperature, having improved compactibility enabling lowering ejection force in compaction, and to provide a process for producing a compact of a high density from the iron-based powder composition, wherein the iron-based powder composition comprises an iron-based powder, a lubricant, and an alloying powder, and at least one of the iron-based powder, the lubricant, and the alloying powder is coated with at least one surface treatment agent selected from the group of surface treatment agents of organoalkoxysilanes, organosilazanes, titanate coupling agents, fluorine-containing silicon silane coupling agents, and wherein the iron-based powder composition is compacted at a temperature not lower than the lowest melting point of the employed lubricants, but not higher than the highest melting point of the employed lubricants.

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: 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: An iron-based mixed powder for use in powder metallurgy has an apparent density of at least about 3.1 Mg/m3, is excellent in die filling property and compressibility and without segregation, and includes an iron-based powder to which alloying powder is adhered at the surface by binder and free lubricant. The iron-based powder includes an atomized iron powder, or a mixed powder of an atomized iron powder and a reduced iron powder.