Kawasaki Steel Corporation

Jfe Steel Corporation

Yoshiaki Maeda

Kuniaki Ogura

Hiroyuki Ishikawa

Shigeaki Takajo

Hiroshi Ohtsubo

Minoru Nitta

Akio Sonobe

Toshiyuki Minegishi

Kouichi Komamura

Takeo Omura

Masaki Kawano

Yukiko Ozaki

Ichio Sakurada

Yutaka Yoshii

Yutyaka Yoshii

Kiyoshi Makino

Keisuke Yoshimura

Kotaro Okawa

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

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.

Method of making iron-based powder mixture

It is disclosed a method for preparing a large-sized powder metallurgical sintered product having a superior characteristic by charging mixtures of three types of metallic powder composed of coarse particles, middle particles and fine particles into the molding die while vibrating it, heating the charged material together with the molding die, sintering them, and infiltrating metal of low melting point into the sintered body. According to this method, it is possible to get a large-sized sintered body having a superior strength and surface smoothness or a sintered body prohibiting any cracks or slits by arranging the proper particle size.

Method for preparing powder metallurgical sintered product

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Chiba, Japan

Yoshiaki Maeda