Abstract: In a die for compressing and sizing a sintered body at straight portions, upper taper portions are provided on a die upper portion and a core rod upper portion, and the straight portions are provided at a die lower portion and a core rod lower portion. The die upper portion and the core rod upper portion have Young's moduli higher than the die lower portion and the core rod lower portion. The die upper portion and the core rod upper portion are made of materials having Young's moduli that are at least 50 GPa higher than that of the sintered body. The sintered body can be densified with a smaller ironing margin. Since the sintered body is ironed without being compressed, by the upper taper portions and the core rod upper portion having high Young's moduli, the die is prevented from breaking and being abraded due to ironing.

Abstract: Provided is a raw material powder for powder metallurgy, capable of preventing stains, surface defects and decarburization of a sintered body, improving strength and density thereof. The raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder and a lubricant, in which the lubricant is melamine cyanurate or terephthalic acid. Alternatively, the raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C, composed of a mixture of a metal powder, a first lubricant and a second lubricant, in which the first lubricant is melamine cyanurate or terephthalic acid, while the second lubricant is preferably erucic acid amide or stearic acid amide.

Abstract: In a die for compressing and sizing a sintered body at straight portions, upper taper portions are provided on a die upper portion and a core rod upper portion, and the straight portions are provided at a die lower portion and a core rod lower portion. The die upper portion and the core rod upper portion have Young's moduluses higher than the die lower portion and the core rod lower portion. The die upper portion and the core rod upper portion are made of materials having Young's moduluses that are at least 50 GPa higher than that of the sintered body. The sintered body can be densified with a smaller ironing margin. Since the sintered body is ironed without being compressed, by the upper taper portions and the core rod upper portion having high Young's moduluses, the die is prevented from breaking and being abraded due to ironing.

Abstract: Provided is a raw material powder for powder metallurgy, capable of preventing stains, surface defects and decarburization of a sintered body, improving strength and density thereof. The raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder and a lubricant, in which the lubricant is melamine cyanurate or terephthalic acid. Alternatively, the raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder, a first lubricant and a second lubricant, in which the first lubricant is melamine cyanurate or terephthalic acid, while the second lubricant is preferably erucic acid amide or stearic acid amide.

Abstract: A sinter of stable quality is produced by molding a powder for powder metallurgy. This process includes successively conducting the following steps: charging a powder and a solid lubricant into a mold compact formation in which the powder charged into the mold is compacted; releasing the compact from the mold; and the powder for powder metallurgy is charged again into the mold after the release step. The temperature of the mold is set at a value in the range of from the boiling point of water to the melting point of the solid lubricant. The compact can be continuously formed without causing, e.g., a failure in the feeding of the powder for powder metallurgy. The sinter obtained by sintering the compact is almost even in strength and density.

Abstract: A method for forming a compact from a powder wherein a forming portion 1A in a mold body 2 is filled with a raw powder and upper and lower punches 3,4 are fitted into the forming portion 1A to form the compact. Prior to filling the forming portion 1A with the raw powder M, a solution L with a lubricant being uniformly dissolved in a solvent is applied to a peripheral portion of the forming portion 1A, and then the solution is evaporated, thus forming a crystallized layer B thereon. Thus, the reduction of a force for ejecting the compact is realized, while improving the density of the compact, realizing the stable and successive production of the compact.

Abstract: A method for forming a compact from a powder wherein a forming portion 1A in a mold body 2 is filled with a raw powder and upper and lower punches 3,4 are fitted into the forming portion 1A to form the compact. Prior to filling the forming portion 1A with the raw powder M, a solution L with a lubricant being uniformly dissolved in a solvent is applied to a peripheral portion of the forming portion 1A, and then the solution is evaporated, thus forming a crystallized layer B thereon. Thus, the reduction of a force for ejecting the compact is realized, while improving the density of the compact, realizing the stable and successive production of the compact.

Abstract: A surface treatment layer 11 is formed on a surface 10 of a through-hole 1 so that the surface 10 has an angle X of contact with solution L which is smaller than an angle Y of contact of a die 2 per se with the solution L. When the solution L is applied, the wetting action of the solution L relative to the through-hole 1 is improved so that the solution L can be extended over the surface treatment layer 11, eventually over the entire surface of the through-hole 1. Consequently, the entire surface thereof can be formed with a crystallized layer by performing water evaporation. As a result, molding at higher temperature can be realized, and high-density compacts can be stably obtained. Further, the solution L in which the lubricant is dissolved in a solvent into a homogeneous phase, is applied to a molding portion 1A, and then evaporated to thereby form crystals thereon, thus forming the crystallized layer.

Abstract: A hydroxy fatty acid salt having an average particle diameter of from 5 ?m to 100 ?m with a composition of from 0.3 wt % to 2 wt %, and more preferably, from 0.5 wt % to 2 wt % is added to a raw material powder in powder metallurgy, and worm molding is performed. In addition, a hydroxy fatty acid salt having an average particle diameter of 50 ?m or less is attached on a mold in advance, and after that, the warm molding is performed. As a hydroxy fatty acid salt, 12-hydroxy lithium stearate is suitably used.

Abstract: This iron-based sintered alloy contains 0.05 to 3% by mass of calcium carbonate or 0.05 to 3% by mass of strontium carbonate. As a result, an iron-based sintered alloy having excellent machinability is obtained.

Abstract: A sinter of stable quality is produced by molding a powder for powder metallurgy. This process includes successively conducting the following steps: charging a powder and a solid lubricant into a mold compact formation in which the powder charged into the mold is compacted; releasing the compact from the mold (1); and the powder for powder metallurgy is charged again into the mold after the release step. The compact is sintered to produce a sinter. The temperature of the mold is set at a value in the range of from the boiling point of water to the melting point of the solid lubricant. The compact can be continuously formed without causing, e.g., a failure in the feeding of the powder for powder metallurgy. The sinter obtained by sintering the compact is almost even in strength and density. Thus, a stable sinter almost even in strength and density can be produced.

Abstract: A hydroxy fatty acid salt having an average particle diameter of from 5 ?m to 100 ?m with a composition of from 0.3 wt % to 2 wt %, and more preferably, from 0.5 wt % to 2 wt % is added to a raw material powder in powder metallurgy, and worm molding is performed. In addition, a hydroxy fatty acid salt having an average particle diameter of 50 ?m or less is attached on a mold in advance, and after that, the warm molding is performed. As a hydroxy fatty acid salt, 12-hydroxy lithium stearate is suitably used.

Abstract: A powder molding product may be formed by a forming portion in a mold body filled with a raw powder. Upper and lower punches are fitted into the forming portion to form the powder molding product. Prior to filling with the raw powder, aqueous solution in which water soluble lubricant having at least 3 g of solubility for 100 g of water is dissolved in water to uniform phase is applied to a mold portion. The aqueous solution is evaporated, thus forming a crystallized layer on the molding portion. The crystallized layer is formed on the peripheral surface of the molding portion for lubrication enabling the reducing of a pressure required for ejecting the powder molding product from the molding portion as well as the improving of the density of the powder molding product.

Abstract: An iron base sintered alloy having highly densified and hardened surface and a producing method thereof are provided. The iron base sintered alloy includes an iron base sintered alloy surface layer portion having a thickness in a range of 1 ?m to 2 mm from a surface of the iron base sintered alloy and containing K and/or Na in an average concentration of 0.0001 to 1 mass %, or having an average concentration of P higher than a concentration of P in an iron base sintered alloy inner portion located inside the iron base sintered alloy surface layer portion and containing K and/or Na in an average concentration of 0.0001 to 1 mass %.

Abstract: This iron-based sintered alloy contains 0.05 to 3% by mass of calcium carbonate or 0.05 to 3% by mass of strontium carbonate. As a result, an iron-based sintered alloy having excellent machinability is obtained.

Abstract: A surface treatment layer 11 is formed on a surface 10 of a through-hole 1 so that the surface 10 has an angle X of contact with solution L which is smaller than an angle Y of contact of a die 2 per se with the solution L. When the solution L is applied, the wetting action of the solution L relative to the through-hole 1 is improved so that the solution L can be extended over the surface treatment layer 11, eventually over the entire surface of the through-hole 1. Consequently, the entire surface thereof can be formed with a crystallized layer by performing water evaporation. As a result, molding at higher temperature can be realized, and high-density compacts can be stably obtained. Further, the solution L in which the lubricant is dissolved in a solvent into a homogeneous phase, is applied to a molding portion 1A, and then evaporated to thereby form crystals thereon, thus forming the crystallized layer.

Abstract: In a method of manufacturing an Fe-based sintered alloy member having excellent dimensional accuracy, strength, and sliding performance, and having a composition comprising: Cu: 0.5 to 7 wt %; C: 0.1 to 0.98 wt %; oxygen: 0.02 to 0.3 wt %; as needed, Mn: 0.0025 to 1.05 wt % and/or Zn: 0.001 to 0.7 wt %; and a balance of Fe and inevitable impurities by blending and mixing an Fe powder, a graphite powder, and a Cu alloy powder as a base powder and by forming and sintering the resultant mixture, in which the Cu alloy powder blended as the base powder has a composition comprising: Fe: 1 to 10 wt %; oxygen: 0.2 to 1 wt %; as needed, Zn: 0.2 to 10 wt % and/or Mn: 0.5 to 15 wt %; and a balance of Cu and inevitable impurities.

Abstract: An iron-based sintered alloy member having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen and, optionally, 0.0025 to 1.05% by mass of Mn and/or 0.001 to 0.7% by mass of Zn, and the balance of Fe and inevitable impurities is manufactured by formulating an Fe powder, a graphite powder and a Cu alloy powder, as raw powders, mixing the powders to form a powder mixture, forming the powder mixture into a green compact and sintering the green compact. The Cu alloy powder has a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen and, optionally, 0.2 to 10% by mass of Zn and/or 0.5 to 15% by mass of Mn, and the balance of Cu and inevitable impurities.

Abstract: A method for forming a compact from a powder wherein a forming portion 1A in a mold body 2 is filled with a raw powder and upper and lower punches 3,4 are fitted into the forming portion 1A to form the compact. Prior to filling the forming portion 1A with the raw powder M, a solution L with a lubricant being uniformly dissolved in a solvent is applied to a peripheral portion of the forming portion 1A, and then the solution is evaporated, thus forming a crystallized layer B thereon.

Abstract: A valve seat made of an Fe-based sintered alloy excellent in wear resistance and having a reduced counterpart valve attack property is disclosed, which comprises a base comprising 15-40% by weight of Cu, 0.3-12% by weight of Ni and 0.0005-3.0% by weight of C, and further comprising 0.1-10% by weight of Co and 0.1-10% by weight of Cr when necessary, with the balance being Fe and inevitable impurities, the base having a structure which comprises an Fe-based alloy phase 1 composed of Fe as a main component combined by a Cu-based alloy phase 2 composed of Cu as a main component, wherein hard particles phase 3 having MHV of 500-1700 is dispersed in the base. The Fe-based alloy phase 1 is an Fe alloy phase which comprises Ni, Cu and C with Fe having more than 50% by weight, while the Cu-based alloy phase 2 is a Cu alloy phase which comprises Ni, Fe and C with Cu having more than 50% by weight.