Keystone Investment Corporation

Keystone Powdered Metal Company

John C Kosco

Peter G Imbrogno

Gary L Anderson

David A Alven

The present invention relates to a process for carburizing a metal article comprising: (1) heating the metal article to an elevated temperature, (2) coating the heated metal article with a graphite suspension to produce a graphite coated metal article, wherein the graphite suspension is comprised of graphite and an organic or inorganic liquid having a boiling point of at least 50&#xb0; F. (28&#xb0; C.) less than the elevated temperature to which the metal article is heated, (3) heat treating the graphite coated metal article under a non-oxidizing environment at a temperature which is sufficient to promote the diffusion of carbon into the metal structure of the article to produce a carburized metal article, and (4) cooling the carburized metal article to ambient temperature.

Carburization of metal articles

The subject invention reveals a process for making hardened powder metal parts which comprises compacting a powder metal composition into a green preformed metal part and subsequently sintering said green metal part to produce the powder metal part at an elevated temperature and subsequently cooling the sintered part at a rate which is sufficient to insure the formation of a substantial amount of martensite, wherein the powder metal composition is comprised of copper powder, a nickel powder and a base iron powder wherein said composition contains from about 1 weight percent to about 5 weight percent of the total sum of said copper powder and said nickel powder and wherein the ratio of the nickel powder to the copper powder is within the range of 1:1 to 9:1, and wherein the balance of said composition constitutes iron.

Process for manufacturing hardened powder metal parts

Embodiments of the present invention relate to methods of forming powder metals materials and parts. More specifically, certain embodiments of the present invention relate to methods of forming powder metals materials and parts by densifying at least a portion of a surface of the materials and/or parts after sintering and prior to densifying one or more core regions of the materials and/or parts. Other embodiment provide powder metal parts, such as gears and sprockets, having surface regions that are uniformly densified to full density to depth ranging from 0.001 inches to 0.040 inches, and core regions that can have at least 92 percent theoretical density and further can have essentially full density, or full density. Still other embodiments relate to brazed, welded, plated and gas-tight powder metal parts and components that can be made in accordance with the various non-limiting methods disclosed herein.

Powder metal materials and parts and methods of making the same

A method of forming a powder metal material includes molding a compact from a powder mix comprising an iron-containing powder and glass, and subsequently sintering the compact. Also disclosed is a sintered powder metal material including iron and glass.

Powder metal materials including glass

A method of forming a powder metal material or article includes the steps of molding a compact from a metallurgical powder, and then sintering the compact. The metallurgical powder may include at least one of a stainless steel powder and a low-chromium steel-base powder, and about 0.5 to about 15 weight percent of glass powder. Alternatively, the metallurgical powder may include at least one of a stainless steel powder and a low-chromium steel-base powder, about 3 to about 15 weight percent molybdenum, and about 1 to about 15 weight percent of nickel-base alloy powder. The present invention also is directed to metallurgical powders useful in and materials and articles made by the methods of the present invention. Such articles include, but are not limited to, valve guides for internal combustion engine EGR systems, valve seats, exhaust system components, combustion chambers, other combustion engine parts subjected to high temperature, and chemical industry valve and corrosion parts.

Powder metal materials having high temperature wear and corrosion resistance

A method of producing a powder metal material includes providing a metallurgical powder including at least one low alloy steel powder and 0.3 up to 1.0 weight percent carbon. At least portions of the powder are molded to provide compacts, and the compacts are then sintered at 1800&deg; F. to 2400&deg; F. The sintered compacts are hot formed and are subsequently heated to 1000&deg; F. to 2300&deg; F. and held at temperature for a predetermined time period. Material produced by the method may have tensile strength greater than 100 ksi, yield strength greater than 80 ksi, Rockwell C hardness of at least 20, and elongation greater than 2%, properties that are similar to ductile cast iron. Accordingly, parts produced by the method may be used in applications in which ductile cast iron parts are conventional. Such applications include, for example, parts for automotive engines and transmissions.

Method for producing powder metal materials

A method of attaching and adjusting first and second members includes providing a first member having an outer surface and a second member. The second member is affixed to the outer surface of the first member at a desired axial position along the length of the first member and in a desired angular orientation. Subsequent to affixing the second member to the first member, the shape and/or dimensions of the second member is adjusted by increasing the density of at least a region of the second member. The densification may be accomplished by, for example, a mechanical working technique such roller burnishing, coining, sizing, shot peening, or laser impacting. In one embodiment of the invention, the method may is adapted to the production of combustion engine camshafts from separately provided camshaft tubes and cam lobes.

Method of fabricating camshafts

A method for producing a material includes providing a metallurgical powder including iron, 1.0 to 3.5 weight percent copper, and 0.3 to 0.8 weight percent carbon. At least a portion of the powder is compressed at 20 tsi to 70 tsi to provide a compact, and subsequently the compact is heated at high temperature and then cooled at a cooling rate no greater than 60&deg; F. per minute to increase the surface hardness of the compact to no greater than RC 25. The density of at least a region of the sintered compact is increased, by a mechanical working step or otherwise, to at least 7.6 grams/cc. The sintered compact is then re-heated to high temperature and cooled at a cooling rate of at least 120&deg; F./min. so as to increase the surface hardness of the compact to greater than RC 25, and preferably at least RC 30. Material made by the method of the invention also is disclosed.

Powdered ferrous metal compositions are disclosed which provide for increased corrosion resistance through the admixing of powder aluminum containing compositions with standard ferrous metal compositions prior to forming the powder metal parts. In a preferred embodiment, the aluminum ranges is admixed as an FeAl alloy powder with the standard ferrous metal composition. The present invention further includes a powder metal ferrous part formed from the composition produced by a method including the steps of (i) providing a ferrous powder metal composition, (ii) admixing a powder aluminum containing composition with the ferrous composition to form a blended mixture, and (iii) forming a powder metal part from at least a portion of the blended mixture. In accordance with the present invention, the admixing of powder aluminum with powder steels increases the corrosion resistance of the resulting part formed from the mixture and allows the use in applications in which the parts are exposed to more aggressive corrosive environments than possible in prior art compositions.

Powder ferrous metal compositions containing aluminum

A method for producing high density and/or high surface density ferrous powder metal parts has the steps of: compacting a iron-containing powder substantially free of graphite at room temperature and at about 40-50 tsi; sintering the green compact in an inert, non-oxidizing environment at a temperature of about 2050.degree.-2300.degree. F.; repressing the sintered compact at room temperature at about 60 tsi; carburizing the repressed compact at high temperature to form a layer of relatively high carbon concentration to a depth of at least about 0.010 inches; and immediately quenching the hot carburized compact followed by a tempering treatment.

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St. Marys, PA, United States of America

John C Kosco