Kawasaki Steel Corporation

Jfe Steel Corporation

Yukiko Ozaki

Satoshi Uenosono

Shigeru Unami

Kuniaki Ogura

Takashi Kawano

Naomichi Nakamura

Tomoshige Ono

Makoto Nakaseko

Yasutaka Fukuda

Michio Shimotomai

Akira Fujita

Junichi Shimomura

Yoko Kitano

Takeo Kobayashi

Hiroki Nakamaru

Toshio Nagase

Masateru Ueta

Kyoko Fujimoto

Tadayuki Tsutsui

Ichio Sakurada

Masashi Fujinaga

Yoshiaki Maeda

Hiroshi Sugihara

Toshio Maetani

Yukiko Nakamura

Shigeaki Takajo

Shingo Saito

Kiyoshi Makino

Kotaro Okawa

Yuji Yamanishi

A method for producing a water-atomized metal powder, comprising applying water to a molten metal stream, dividing the molten metal stream into a metal powder, and cooling the metal powder, wherein the metal powder is further subjected to secondary cooling with cooling capacity having a minimum heat flux point (MHF point) higher than the surface temperature of the metal powder in addition to the cooling and the secondary cooling is performed from a temperature range where the temperature of the metal powder after the cooling is not lower than the cooling start temperature necessary for amorphization nor higher than the minimum heat flux point (MHF point).

Method for producing water-atomized metal powder

A water-atomized metal powder is produced by dividing a molten metal stream into a metal powder by making injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more impinge on the molten metal stream and cooling the metal powder. Cooling with injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more enables can be performed not in the film boiling region but in the transition boiling region from the beginning of cooling. A gas-atomized metal powder may also be produced by dividing a molten metal stream into a metal powder by making an inert gas impinge on the molten metal stream and cooling the metal powder with injection water having a liquid temperature of 10&#xb0; C. or less and an injection pressure of 5 MPa or more.

Method of producing atomized metal powder

An iron-based powder for powder metallurgy effectively prevents agglomeration of a lubricant, has excellent flowability, can evenly fill thin-walled cavities, keeps the ejection force after formation low, and does not lower sintered body strength by adhering either or both of an alloy component and a cutting ability improving agent to the surface of iron powder with a binder that has a melting point of 150&#xb0; C. or lower, adhering carbon black to the surface of the binder, and setting the amount of free binder to 0.02 mass % or less.

Iron-based powder for powder metallurgy

The present invention provides a method for mixing a raw material powder for powder metallurgy that allows efficient mixing at a low cost with a simple measure and easy adjustment of the apparent density by performing first agitation mixing in which a powder mixture obtained by adding, to an iron powder, one or two or more members selected from lubricant powders, free-machining agent powders, and lubricant powders for sliding surface, an alloying powder, and a binding agent is agitated while increasing the temperature to a temperature Tequal to or higher than the melting point Tof the binding agent, the resultant is agitated while maintaining the temperature T, and the resultant is further agitated while reducing the temperature from the temperature T, and performing second agitation mixing in which the obtained powder mixture is agitated while cooling.

Method for mixing raw material powder for powder metallurgy and method for producing raw material powder for powder metallurgy

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 &#x3bc;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.

Highly compressible iron powder

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.

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 &#x3bc;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.

Iron-based mixed powder for powder metallurgy

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.

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.

Mixed powder for powder metallurgy

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.

Iron-based mixed powder for powder metallurgy and sintered body

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. The at least two different lubricants having melting points higher than the predetermined temperature of the compaction pressure are preferably at least two materials selected from at least one of the following groups: metallic soaps, amide-based waxes, polyamides, polyethylenes, polypropylenes, polymers comprised of acrylic acid esters, polymers having methacrylic acid ester, plastics including fluorine and lubricants having layered crystal structures.

Lubricants for die lubrication and manufacturing method for high density iron-based powder compacts

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.

Powder additive for powder metallurgy, iron-based powder mixture for powder metallurgy, and method for manufacturing the same

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.

Magnetite-iron based composite powder, magnetite-iron based powder mixture, method for producing the same, method for remedying polluted soil, water or gases and electromagnetic wave absorber

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.

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.

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Chiba, Japan

Yukiko Ozaki