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 iron-based mixed powder for powder metallurgy having improved machinability, without degrading the mechanical property of a sintered body made by compacting the iron-based mixed power. The iron-based mixed powder comprises a mixture of an iron-based powder, a powder for an alloy, a powder for machinability improvement, and a lubricant. The powder for machinability improvement comprises a manganese sulfide powder, and at least one selected from the group consisting of a calcium phosphate powder and a hydroxy apatite powder. Alternatively the powder for machinability improvement has an average particle diameter of 1 to 60 micrometers and comprise manganese sulfide powder and calcium fluoride 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: The invention provides an iron-based mixed powder for powder metallurgy enabling the iron-based mixed powder to improve the machinability, without being accompanied by degrading the mechanical property of a sintered body. In order to obtain the purpose of the invention, the iron-based mixed powder comprises a mixture of an iron-based powder, a powder for an alloy, a powder for machinability improvement, while further adding lubricant. And, (1) the powder for machinability improvement comprises a manganese sulfide powder, and at least one selected from the group consisting of a calcium phosphate powder and a hydroxy apatite powder, or, (2) the powder for machinability improvement has an average particle diameter of 1 to 60 micrometers and is at least one selected from the group consisting of manganese sulfide powder and calcium fluoride powder.

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: 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: 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: 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 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: 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 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: 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: 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: 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.

Abstract: An iron-based powder composition is provided that is greatly flowable and compactible and less dependent on temperature with respect to flowability and compactibility at room temperature or during warming. The iron-based powder composition includes an iron-based powder, a lubricant melted and fixed to the iron-based powder, an alloying powder bonded to the iron-based powder with the aid of the lubricant, and a free lubricant. One or more constituent members are coated with an organosiloxane layer in a coating ratio of greater than about 80%. The organosiloxane has phenyl groups as a functional group. The lubricant melted and fixed to the iron-based powder is a composite melt composed of a calcium soap and a lithium soap, or a composite melt composed of a calcium soap and an amide lubricant. The free lubricant is a mixed powder composed of an amide lubricant and a methyl polymethacrylate powder, or a lithium soap powder. A process for producing the iron-based powder composition is also provided.

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: A process for producing a high-density iron-based green compact is provided that can form a green compact with a high density. Also provided is a process for producing a sintered compact from the green compact. A specified combination lubricant is applied to the surface of a die for compacting by electrical charging, wherein the combination lubricant includes a first lubricant having a melting point that is higher than a preset compacting temperature, and a second lubricant having a melting point that is lower than a compacting temperature. A heated iron-based powder mixture is filled into the die, followed by compacting, whereby a green compact is formed. The green compact can be sintered to provide a sintered compact.

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.