Kawasaki Steel Corporation

Jfe Steel Corporation

Kuniaki Ogura

Satoshi Uenosono

Yoshiaki Maeda

Yukiko Ozaki

Hiroyuki Ishikawa

Shigeaki Takajo

Hiroshi Ohtsubo

Minoru Nitta

Ichio Sakurada

Teruyoshi Abe

Masaki Kawano

Akio Sonobe

Toshiyuki Minegishi

Kouichi Komamura

Takeo Omura

Takeo Kobayashi

Osamu Furukimi

Toshio Nagase

Shunji Ito

Yoshihiro Kajinaga

Yutaka Yoshii

Keiichi Maruta

Junichi Oota

Keisuke Yoshimura

Yutyaka Yoshii

Jibin Yang

Kotaro Okawa

Kiyoshi Makino

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 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.

Iron-based powder composition for powder metallurgy having higher flowability and higher compactibility and process for production thereof

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.

Iron-based powder mixture for powder metallurgy, process for producing the same, and method of forming a molding from the same

The present invention intends to provide 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, to provide a process for producing the iron-based powder composition, and to provide a process for producing a compact of a high density from the iron-based powder composition. 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. 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.

Iron base powder mixture for powder metallurgy excellent in fluidity and moldability, method of production thereof, and method of production of molded article by using the iron base powder mixture

An iron-based powder composition is produces in accordance with a method comprising the steps of: adding to iron-based and alloying powders, for a primary mixing, a surface treatment agent, and in addition, for a secondary mixing, a fatty acid amide and at least one lubricant, wherein the lubricant has a melting point higher than that of the fatty acid amide and can be, a thermoplastic resin, a thermoplastic elastomer, and inorganic or organic compounds having a layered crystal structure; heating and stirring up a mixture after the secondary mixing at a temperature above a melting point of the fatty acid amide to melt the fatty acid amide; cooling, while mixing, the mixture subjected to the heating and stirring process so that the alloying powder and a lubricant having a melting point higher than the fatty acid amide adhere to a surface of the iron base powder subjected to the surface treatment by an adhesive force of the melt; and adding at the time of the cooling, for a tertiary mixing, a metallic soap and at least one a thermoplastic resin or thermoplastic elastomer powders and inorganic or organic compounds having layered crystal structure. The mixture is heated to about 423K and loaded into a die for compaction.

Method of making iron-based powder composition for powder metallurgy

Iron-based powder composition for powder metallurgy excellent in

An iron-based powder mixture for powder metallurgy, comprising: an iron-based powder, and from 0.05 to 0.50% by weight of a thermoplastic resin powder which comprises 50% or more by weight of units of at least one monomer selected from the group consisting of acrylic esters, methacrylic esters, and aromatic vinyl compounds, and whose average primary particle size is from 0.03 to 5 .mu.m, whose average agglomeration particle size is from 5 to 50 .mu.m, and whose average molecular weight measured by the specific viscosity of a solution is from 30000 to 5000000.

Iron-based powder mixture for powder metallurgy and process for

An iron based powder mixture for powder metallurgy is provided which can produce a sintered material having by far higher machinability and sliding properties than conventional sintered materials, and also a sintered material containing alloy elements but having adaptability to sizing even after sintering; it comprises an atomized iron powder comprising S in a content of 0.03 to 0.30 wt %, Mn in a content of 0.05 to 0.40 wt % and the balance Fe and incidental impurities, to which is added one or more than one B-containing compound powder selected from boron nitride (BN), boric acid (H.sub.3 BO.sub.3), boron oxide (B.sub.2 O.sub.3) and the like in an amount of 0.001 to 0.3 wt % expressed as B, and incorporated with an MnS powder in an amount of 0.05 to 1.0 wt %, optionally alloyed partially with or prealloyed with Ni, Mo and Cu.

Iron based powder mixture for powder metallurgy

An iron-base mixture and method for powder metallurgy containing iron-base powder, an alloy powder including at least copper, copper oxide or both, and an organic substance for bonding the alloy powder to the iron-base powder, wherein said copper powder or copper oxide powder has a particle size of agglomeration, when evaluated by the micro-track method, of about 5 .mu.m to 28 .mu.m, and wherein the particles of copper or copper oxide have a primary particle size which, when evaluated by the BET method, is about 0.2 .mu.m to 1.5 .mu.m.

Iron-base powder mixture for powder metallurgy and manufacturing method

A mixed iron powder for powder metallurgy containing less than about 0.1 wt % of Mn, about 0.08 to 0.15 wt % of S, a total of about 0.05 to 0.70 wt % of one or more compounds selected from MoO.sub.3 and WO.sub.3, about 0.50 to 1.50 wt % of graphite powder, and the balance Fe and incidental impurities. The mixed iron powder can be manufactured by an atomizing process using water, and be used to manufacture a sintered steel having excellent machinability, strength and toughness without forming soot, even if sintered in a hydrogen-containing atmosphere.

Mixed iron powder for powder metallurgy

Atomized steel powder having excellent machinability, containing about S 0.005 wt % to 0.3 wt %, Cr 0.03 wt % to 0.3 wt %, Mn 0.03 wt % to 0.5 wt %, O 0.30 wt % or less, and the balance Fe and incidental impurities, and sintered steel that can be manufactured therefrom. In particular, each of specific components is limited to a preferred range so that atomized steel powder exhibiting excellent machinability, dimensional accuracy and wear resistance and sintered steel that can be manufactured therefrom are provided.

Atomized steel powder excellent machinability and sintered steel

Water-atomized iron powder for powder metallurgy having a hardness of particle cross section of from about Hv 80 or higher to about 250 or lower, the iron powder having been atomized with water and dried, and having a particle surface covered with oxides which are reducible in a sintering atmosphere, and which has an oxygen content of 1.0 wt % or less. The water-atomized ion powder can be made by an improved and simplified processing, and the cost of resulting sintered products is decreased as a result of its use.

Water-atomized iron powder and method

This invention is to control the diffusion of C (carbon) from added graphite to particles of iron powder in the sintering to thereby improve the accuracy of dimensional change in the sintered body by using iron powder for powder metallurgy and a mixed powder thereof as a starting material in the production of sintered mechanical parts by adding the iron powder with Cu powder and graphite powder and companying and sintering them, in which 0.008-0.5 wt % in total of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/l mol of O.sub.2 is included in the iron powder and not less than 20% of the element is rendered into an oxide, or 0.01-0.20 wt % in total of an oxide powder of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/l mol of O.sub.2 is added to the mixed powder.

Iron powder and mixed powder for powder metallurgy as well as method of

An iron-based powder mixture for powder metallurgy essentially consists of a melted mixture, as a binder, which includes about 0.1% to about 1.0% by weight of a powder of at least one organic compound selected from stearic acid, oleic acid amide, and stearic acid amide, and about 0.1% to about 1.0% by weight of a powder of stearic acid bisamide; and the balance which is an iron-based powder, to the surface of which adhered about 0.1% to about 3.0% by weight of an alloying powder and/or a powder for improving machinability. Disclosed also is a method of producing the mixture.

Iron-based powder mixture and method

Water-atomized iron powder for powder metallurgy having a hardness of particle cross section of from about Hv 80 or higher to about 250 or lower, the iron powder having been atomized with water and dried, and having a particle surface covered with oxides which are reducible in a sintering atmosphere, and which has an oxygen content of 1.0 wt. % or less. The water-atomized ion powder can be made by an improved and simplified processing, and the cost of resulting sintered products is decreased as a result of its use.

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Chiba, Japan

Kuniaki Ogura