Mitsubishi Materials Corporation

Diamet Corporation

Kinya Kawase

Takashi Nakai

Koichiro Morimoto

Yoshinari Ishii

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.

Sizing die for densifying surface of sintered body, production method using same, and product obtained therefrom

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&#xb0; 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&#xb0; 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.

Raw material powder for powder metallurgy

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.

Method of producing powder sintered product

A method for forming a compact from a powder wherein a forming portionA in a mold bodyis filled with a raw powder and upper and lower punchesare fitted into the forming portionA to form the compact. Prior to filling the forming portionA 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 portionA, 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.

Method for forming compact from powder and sintered product

A surface treatment layeris formed on a surfaceof a through-holeso that the surfacehas an angle X of contact with solution L which is smaller than an angle Y of contact of a dieper se with the solution L. When the solution L is applied, the wetting action of the solution L relative to the through-holeis improved so that the solution L can be extended over the surface treatment layer, eventually over the entire surface of the through-hole. 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 portionA, and then evaporated to thereby form crystals thereon, thus forming the crystallized layer.

Powder molding die apparatus and method of molding for obtaining powder molding product

A hydroxy fatty acid salt having an average particle diameter of from 5 &#x3bc;m to 100 &#x3bc;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 &#x3bc;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.

Warm molding raw material powder and warm molding method

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.

Iron-based sintered alloy having excellent machinability

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 composed of Fe as a main component combined by a Cu-based alloy phase composed of Cu as a main component, wherein hard particles phase having MHV of 500-1700 is dispersed in the base. The Fe-based alloy phase 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 is a Cu alloy phase which comprises Ni, Fe and C with Cu having more than 50% by weight. At the same time, the contents of Ni and C included in the Fe-based alloy phase are more than those of Ni and C included in the Cu-based alloy phase.

Fe-based sintered valve seat having high strength and method for producing the same

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. At the same time, the contents of Ni and C included in the Fe-based alloy phase are more than those of Ni and C included in the Cu-based alloy phase.

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Niigata, Japan

Kinya Kawase