Kawasaki Steel Corporation

Yoshihiro Kajinaga

Ichio Sakurada

Shunji Ito

Minoru Nitta

Kuniaki Ogura

Yasuaki Morioka

An alloy steel powder having a basic alloy composition, which is composed of at least one of manganese, chromium, molybdenum and vanadium, and the remainder being iron, and having low carbon, nitrogen and oxygen contents is excellent in the compressibility and moldability at the press molding and further excellent in the carburizing property and hardenability in its sintered steel or powder forged steel.

Alloy steel powder having excellent compressibility, moldability and

A process and an apparatus for producing low-oxygen iron-base metallic powder are disclosed. The low-oxygen iron-base metallic powder is produced by alloying and/or admixing iron-base metallic raw powder to be subjected to a final reduction, which has an apparent density in filled state corresponding to 16-57% of theoretical true density, an oxygen content of not more than 6% by weight and a particle size of not more than 1 mm, with carbon or carbonaceous granule in an amount corresponding to not more than an target alloying carbon content of a final product (% by weight) + an oxygen content of the powder just before the final reduction (% by weight) .times. 1.35 to form a starting powder, preheating the starting powder at a temperature of 780.degree.-1,130.degree. C. in a non-oxidizing atmosphere having a theoretical oxygen partial pressure of not more than 2.1.times.10.sup.-1 mmHg and a dew point of not more than +5.degree. C. to form a preheated and sintered cake (P-cake), induction heating the P-cake at a temperature of 850.degree.-1,400.degree. C. in the same atmosphere by applying an alternating power of 50 Hz to 500 kHz from power supply to effect deoxidation and decarburization to form an induction heated cake (I-cake), and then cooling and pulverizing the I-cake.

Apparatus for producing low-oxygen iron-base metallic powder

A shaft furnace for producing low-oxygen iron-base metallic powder for metallurgy is disclosed. The shaft furnace comprises a zone of storing and feeding a metallic raw powder, a preheating zone, an induction heating zone and a zone of cutting and cooling a product cake in a vertical array from top to bottom. The preheating zone and induction heating zone have a special structure for ensuring a smooth descent of the raw powder and the cake.

Shaft furnace for producing low-oxygen iron-base metallic powder for

A process for producing low-oxygen iron-base metallic powder are disclosed. The low-oxygen iron-base metallic powder is produced in a shaft-type apparatus comprising a preheating zone and an induction heating zone by alloying and/or admixing iron-base metallic raw powder to be subjected to a final reduction, which has an apparent density corresponding to 16 to 57% of theoretical true density, an oxygen content of not more than 6% by weight and a particle size of not more than 1 mm, with carbon or carbonaceous granule in an amount corresponding to not more than a target alloying carbon content of a final product (% by weight)+ an oxygen content of the powder just before the final reduction (% by weight).times. 1.35 to form a starting powder, preheating the starting powder at a temperature of 780.degree. to 1,200.degree. C. in a non-oxidizing atmosphere having a thermodynamically calculated oxygen partial pressure of not more than 2.1.times.10.sup.-1 mmHg and a dew point of not more than +5.degree. C. in the preheating zone to form a preheated and sintered cake (P-cake) with cylindrically sintered shell layer wherein the volume ratio of the shell layer is at least 20%, induction heating the P-cake at a temperature of 850.degree. to 1,400.degree. C. in the same atmosphere by applying an alternating power of 50 Hz to 500 kHz from power supply to effect deoxidation and decarburization to form an induction heated cake (I-cake), and then cooling and pulverizing the I-cake.

Process for producing low-oxygen iron-base metallic powder

A metal block having a high density can be easily obtained directly from metal powder by charging the metal powder in a metallic container, disposing carbonaceous powder through a partition plate on the metal powder so as to interrupt the metal powder from the air, uniformly heating the metal powder in the air together with the container and subjecting the metal powder in the air together with the container to a primary hot working and to a secondary hot working with or without effecting a uniform heating step.

Method for producing metal block having a high density with metal powder

Iron or iron alloy powders having a low oxygen content to be used for powder metallurgy are produced by subjecting iron or iron alloy powder materials having an oxygen content of not more than 8% by weight and a total carbon amount including carbon alloyed in said powders being not more than 6% by weight corresponding to the oxygen content to an induction heating under a relative density of 5-65% based on a density of the molding steel of said powders by means of an alternating current of 50 cycles-1 megacycle to heat said powders at a temperature of 750.degree.-1,400.degree.C to effect reduction rapidly.

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Chiba, Japan

Yoshihiro Kajinaga