Hoeganaes Corporation

Davy Mckee (sheffield) Limited

Robert J Causton

Denis B Christopherson, Jr

Christopher T Schade

John J Fulmer

William B James

Denis Christopherson

Metallurgical powder compositions are provided that include calcium aluminate additives, i.e., calcium aluminate or calcium aluminate containing powders, to enhance the machinability and durability of compacted and sintered parts made therefrom. The compositions generally contain a metal-based powder, such as for example, an iron-based or nickel-based powder, that constitutes the major portion of the composition. Calcium aluminate additives are combined with the metal based powder by, for example, admixing or bonding. Optionally, common alloying powders, lubricants, binding agents, and other powder metallurgy additives can be combined with the metallurgical powder composition. The metallurgical powder composition is used by compacting it in a die cavity to produce a 'green' compact that may then be sintered, preferably at relatively high temperatures.

Powder metallurgical compositions and parts made therefrom

A steel powder composition useful in the production, by powder-metallurgical methods, of sintered parts with high density, good dimensional accuracy, hardenability, and strength is prepared from an admixture of two pre-alloyed iron powders of different compositions, the first being a pre-alloy of iron and molybdenum, and the second being a pre-alloy of iron with carbon and at least one transition element including chromium, manganese, vanadium, or columbium.

Steel powder composition

Steel powder admixture having distinct prealloyed powder of iron alloys

Methods for preparing sintered components from iron-containing and alloy steel powder are provided. The methods includes compacting a powder mixture in a die set at a pressure of at least about 25 tsi to produce a green compact which is then presintered at a temperature of about 1100.degree.-1600.degree. F. (593.degree.-870.degree. C.) for at least about 5 minutes to produce a presintered preform. The presintered preform is then compacted at a pressure of at least about 25 tsi to produce a double-pressed presintered preform, which is, in turn, sintered at a temperature of at least about 1000.degree. C. for at least about 5 minutes to produce a sintered component having improved transverse rupture strength and a higher density.

Optimized double press-double sinter powder metallurgy method

In order to anneal high speed steel powder having a hardness of the order of about 550 to 600 Vickers and an oxygen content of 1500-2000 ppm, the powder is heated to a maximum temperature of about 1050.degree. C. and held at that temperature for about one hour. The powder is then gas quenched to between 700.degree. and 780.degree. C., held at that temperature for about one hour, and finally gas quenched to ambient temperature.

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Delran, NJ, United States of America

Robert J Causton