# US 11,992,880 B1 · Acoustical dampening powder metal parts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,992,880 B1 - Document ID: US11992880B1 - Status: Granted - Kind: B1 - Application number: 16/934,580 - Filed: 2020-07-21 - Granted: 2024-05-28 - Earliest claimed: 2019-07-22 - Assignees: Keystone Powdered Metal Company - Applicants: Peter G. Imbrogno - Inventors: Peter G. Imbrogno - Web page: https://patentgrep.com/patent/US11992880B1 ## CPC - B22F 5/085: {with helical contours} - B22F 7/008: {characterised by the composition} - B22F 1/10: Metallic powder containing lubricating or binding agents; Metallic powder containing organic material - B22F 5/08: of toothed articles, e.g. gear wheels; of cam discs - C22C 33/0264: {the maximum content of each alloying element not exceeding 5%} - C22C 38/00: Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) - C22C 38/08: containing nickel {(C22C38/105 takes precedence)} - C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium - C22C 38/16: containing copper - B22F 2003/023: {Lubricant mixed with the metal powder} - B22F 2003/166: {Surface calibration, blasting, burnishing, sizing, coining} - B22F 2003/241: {Chemical after-treatment on the surface} - B22F 2003/247: {Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface} - B22F 2003/248: {Thermal after-treatment} - B22F 2302/40: Carbon, graphite - B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - C22C: ALLOYS (treatment of alloys C21D, C22F) ## Abstract It has been unexpected found that the sound dampening characteristics of powder metal parts can be dramatically improved by incorporating coarse graphite into the part. This is beneficial in applications where parts to generate noise during operation, such as in gears, rotors and sprockets. Surprisingly, the incorporation of the coarse graphite into such parts does not significantly compromise the strength, durability, wear characteristics, or service life of the part. Such parts can also be manufactured to a high level of tolerance and with good uniformity. Such parts are comprised of a sintered powder metal composition which includes 0.1 weight percent to 5 weight percent of a coarse graphite having a particle size wherein at least at least 30 percent of the coarse graphite will not pass through a 325 mesh screen. ## Claims ### Claim 1 A powder metal part which consists of a sintered powder metal composition, wherein the powder metal composition consists of a coarse graphite wherein the coarse graphite is present at a level which is within the range of 1 weight percent to 5 weight percent, optionally nickel, optionally molybdenum, optionally copper, optionally phosphorus, optionally magnesium, optionally silicon, optionally chromium, optionally aluminum, optionally titanium, optionally vanadium, optionally calcium, optionally zinc, and optionally cobalt, and optionally 0.02 to 2% of a standard graphite having a D50 particle size distribution which is within the range of 8 μm to 14 μm and a D90 particle size distribution which is within the range of 15 μm to 21 μm, with the balance of the powder metal composition being iron, wherein the coarse graphite is of a particle size wherein at least 30 percent of the coarse graphite will not pass through a 325 mesh screen, and wherein the powder metal part is a gear. ### Claim 2 (depends on 1) The powder metal part of claim 1 wherein the powder metal part is a pump gear. ### Claim 3 (depends on 1) The powder metal part of claim 1 wherein the powder metal part is a transmission gear. ### Claim 4 (depends on 1) The powder metal part of claim 1 wherein the gear is a helical gear. ### Claim 5 (depends on 4) The powder metal part of claim 4 wherein the helical gear is a herringbone gear. ### Claim 6 (depends on 1) The powder metal part of claim 1 wherein the part has a density which is within the range of 6.6 g/cc to 7.5 g/cc. ### Claim 7 (depends on 1) The powder metal part of claim 1 wherein the part has a density which is within the range of 6.9 g/cc to 7.3 g/cc. ### Claim 8 (depends on 1) The powder metal part of claim 1 wherein the powder metal composition contains the 0.02 to 2% of a standard graphite having a D50 particle size distribution which is within the range of 8 μm to 14 μm and a D90 particle size distribution which is within the range of 15 μm to 21 μm, and wherein molybdenum is present in the powder metal composition at a level which is within the range of 0.4% to 2%. ### Claim 9 (depends on 8) The powder metal part of claim 8 wherein the powder metal composition consists of the iron, the molybdenum, the coarse graphite powder, and the standard graphite, and wherein the coarse graphite is present in the powder metal composition at a level which is within the range of 1.25 weight percent to 3 weight percent. ### Claim 10 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite is present in the powder metal composition at a level which is within the range of 1.5 weight percent to 2 weight percent. ### Claim 11 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite is of a particle size wherein at least 35 percent of the coarse graphite will not pass through a 325 mesh screen. ### Claim 12 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite is of a surface area which is within the range of 2.9 m2/g to 3.5 m2/g. ### Claim 13 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite is of a surface area which is within the range of 3.0 m2/g to 3.3 m2/g. ### Claim 14 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite has an average particle size which is within the range of 35 microns to 55 microns. ### Claim 15 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite has a Scott Volume which is within the range of 4.5 g/in 3 to 5.0 g/in3. ### Claim 16 (depends on 1) The powder metal part of claim 1 wherein the coarse graphite has a Scott Volume which is within the range of 4.6 g/in 3 to 4.9 g/in3. ### Claim 17 (depends on 1) The powder metal part of claim 1 wherein the metal composition contains 0.4% to 2% molybdenum and 1.0% to 4% coarse graphite with the balance of the composition being iron. ### Claim 18 A powder metal part which consists of a sintered powder metal composition, wherein the powder metal composition consists of a coarse graphite wherein the coarse graphite is present at a level which is within the range of 1 weight percent to 5 weight percent, optionally nickel, optionally molybdenum, optionally phosphorus, optionally magnesium, optionally silicon, and optionally chromium, with the balance of the powder metal composition being iron, wherein the coarse graphite is of a particle size wherein at least 30 percent of the coarse graphite will not pass through a 325 mesh screen, and wherein the powder metal part is a gear. ### Claim 19 (depends on 18) The powder metal part of claim 18 wherein the metal composition contains 0.6% to 1.1% molybdenum, 1.5% to 2% coarse graphite, and 0.5% to 1% standard graphite with the balance of the composition being iron, wherein the standard graphite has a D50 particle size distribution which is within the range of 8 μm to 14 μm and a D90 particle size distribution which is within the range of 15 μm to 21 μm.