Patents by Inventor Rohith Shivanath
Rohith Shivanath has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11465209Abstract: A densified, high-strength metallic component is manufactured by: binder jet additive manufacture (BJAM) printing a powder blend to form a printed part; and super solidus sintering the printed part to form the metallic component, which may then be heat treated. The powder blend comprises a blend of water atomized base iron powder and a high-carbon master ferroalloy powder. The high-carbon ferroalloy powder introduces high concentrations of carbon into a powder blend that is readily BJAM printable.Type: GrantFiled: May 9, 2019Date of Patent: October 11, 2022Assignee: Stackpole International Powder Metal LLCInventors: Rohith Shivanath, Peng Shen, Vincent Williams
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Patent number: 11114677Abstract: An interconnector for a solid oxide fuel cell is manufactured by single-press compacting a powder blend to form a green interconnector with a desired shape of a final interconnector. The powder blend includes chromium and iron, and may include an organic lubricant. At least 50 wt % or more of an iron portion of the powder blend comprises iron particles smaller than 45 um. The green interconnector is then sintered and oxidized to form the final interconnector. The oxidation step occurs in a continuous flow furnace in which a controlled atmosphere (e.g., humidified air) is fed into the furnace in the travel direction of the interconnector. The final interconnector comprises at least 90 wt % chromium, at least 3 wt % iron, and less than 0.2 wt % nitrogen. An average density within a flow field of the final interconnector may be less than 6.75 g/cc.Type: GrantFiled: July 8, 2013Date of Patent: September 7, 2021Assignee: Stackpole International Powder Metal, ULCInventors: Roger Lawcock, Brendan Ayre, Rohith Shivanath
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Publication number: 20190344344Abstract: A densified, high-strength metallic component is manufactured by: binder jet additive manufacture (BJAM) printing a powder blend to form a printed part; and super solidus sintering the printed part to form the metallic component, which may then be heat treated. The powder blend comprises a blend of water atomized base iron powder and a high-carbon master ferroalloy powder. The high-carbon ferroalloy powder introduces high concentrations of carbon into a powder blend that is readily BJAM printable.Type: ApplicationFiled: May 9, 2019Publication date: November 14, 2019Inventors: Rohith SHIVANATH, Peng SHEN, Vincent WILLIAMS
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Patent number: 9993874Abstract: A chromium-iron interconnect includes at least one of Fe rich regions in the interconnect and carbon in the interconnect.Type: GrantFiled: February 24, 2015Date of Patent: June 12, 2018Assignees: BLOOM ENERGY CORPORATION, STACKPOLE INTERNATIONAL POWDER METAL, ULCInventors: Rohith Shivanath, Brendan Ayre, Tad Armstrong, Michael Gasda, Daniel Darga, Harald Herchen, Chockkalingam Karuppaiah, Brandon Dawson, Ravi Oswal
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Publication number: 20150244004Abstract: A chromium-iron interconnect includes at least one of Fe rich regions in the interconnect and carbon in the interconnect.Type: ApplicationFiled: February 24, 2015Publication date: August 27, 2015Inventors: Rohith SHIVANATH, Brendan AYRE, Tad ARMSTRONG, Michael GASDA, Daniel DARGA, Harald HERCHEN, Chockkalingam KARUPPAIAH, Brandon DAWSON, Ravi OSWAL
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Publication number: 20150207154Abstract: An interconnector for a solid oxide fuel cell is manufactured by single-press compacting a powder blend to form a green interconnector with a desired shape of a final interconnector. The powder blend includes chromium and iron, and may include an organic lubricant. At least 50 wt % or more of an iron portion of the powder blend comprises iron particles smaller than 45 um. The green interconnector is then sintered and oxidized to form the final interconnector. The oxidation step occurs in a continuous flow furnace in which a controlled atmosphere (e.g., humidified air) is fed into the furnace in the travel direction of the interconnector. The final interconnector comprises at least 90 wt % chromium, at least 3 wt % iron, and less than 0.2 wt % nitrogen. An average density within a flow field of the final interconnector may be less than 6.75 g/cc.Type: ApplicationFiled: July 8, 2013Publication date: July 23, 2015Inventors: Rohith Shivanath, Brendan Ayre, Roger Lawcock
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Patent number: 8231827Abstract: A method of manufacturing powder metal plates comprising feeding a predetermined mass of metal powder onto a moving tape (101), restricting the metal powder by surrounding the metal powder with vibrating boundary walls (201, 202) extending parallel to the direction of movement of the tape, rolling the metal powder at an ambient temperature to form a green compact strip (GS), continuously sintering the green compact strip in a furnace (400), forming the green compact strip to a net shape part (NS) while in the furnace, and cooling the net shape part in a non-oxidizing environment (404) at a temperature in excess of 1000 degrees Celsius.Type: GrantFiled: June 17, 2009Date of Patent: July 31, 2012Assignee: The Gates CorporationInventors: Yahya Hodjat, Roger Lawcock, Rohith Shivanath
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Publication number: 20100322811Abstract: A method of manufacturing powder metal plates comprising feeding a predetermined mass of metal powder onto a moving tape (101), restricting the metal powder by surrounding the metal powder with vibrating boundary walls (201, 202) extending parallel to the direction of movement of the tape, rolling the metal powder at an ambient temperature to form a green compact strip (GS), continuously sintering the green compact strip in a furnace (400), forming the green compact strip to a net shape part (NS) while in the furnace, and cooling the net shape part in a non-oxidizing environment (404) at a temperature in excess of 1000 degrees Celsius.Type: ApplicationFiled: June 17, 2009Publication date: December 23, 2010Inventors: Yahya Hodjat, Roger Lawcock, Rohith Shivanath
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Patent number: 6365094Abstract: A toolset for forming a component from a powdered metal charge includes a die having two zones on the sidewall. Lubricant is applied to one of the zones. The powdered metal charge is initially compressed to an intermediate density and the lubricated zone of the sidewall brought into contact with the partially compressed charge. The charge is then further compressed to a final density.Type: GrantFiled: January 31, 2000Date of Patent: April 2, 2002Assignee: Stackpole LimitedInventors: Gerd Hinzmann, Karol Kucharski, Rohith Shivanath
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Patent number: 6346213Abstract: A process of forming a sintered article of powder metal comprising blending graphite, Si carbide and lubricant, with pre-alloyed iron base powder; pressing said blended mixture to a shaped article; sintering said article in a reduced atmosphere; forced cooling said sintered article.Type: GrantFiled: November 29, 1999Date of Patent: February 12, 2002Assignee: Stackpole LimitedInventors: Rohith Shivanath, Karol Kucharski, Peter Jones
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Patent number: 6019937Abstract: A process of forming a sintered article of powder metal comprising blending graphite, Si carbide and lubricant, with pre-alloyed iron base powder; pressing said blended mixture to a shaped article; sintering said article in a reduced atmosphere; forced cooling said sintered article.Type: GrantFiled: November 27, 1998Date of Patent: February 1, 2000Assignee: Stackpole LimitedInventors: Rohith Shivanath, Karol Kucharski, Peter Jones
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Patent number: 5884527Abstract: A gear wheel is formed from a pressed and sintered powder metal blank in which the metal powder comprises an admixture of iron powder and at least one alloying addition and the gear wheel is surface hardened by applying densifying pressure only to the tooth root regions or only to the tooth flank regions in order to establish densification in the range of 90 to 100 per cent of full theoretical density to a depth of at least 380 and up to about 1,000 microns.Type: GrantFiled: September 4, 1997Date of Patent: March 23, 1999Assignee: Formflo LimitedInventors: Christopher John Cole, Rohith Shivanath, Peter Jones
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Patent number: 5881354Abstract: A method of making a sintered article of powder metal having a carbon composition in the range of about 0.8% to 2.0% by weight, then spheroidizing the sintered article and then warm forming the sintered article at a temperature between 250.degree. and 700.degree. C. for a time duration selected to form the article to a final shape.Type: GrantFiled: May 3, 1996Date of Patent: March 9, 1999Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones
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Patent number: 5834640Abstract: This invention relates to a method or process of forming a sintered article of powder metal, and particularly relates to a process of forming a sintered article of powder metal by blending combinations of finely ground ferro alloys (either singly or in combination with other ferro alloys) with elemental iron powder and other additives and then high temperature sintering of the article in a reducing atmosphere to produce sintered parts with oxygen contents less than 250 parts per million (ppm). More particularly the ferro alloys admixed to the base iron have a mean particle size of approximately 8 to 12 microns, having previously been ground to size in an inert atmosphere.Type: GrantFiled: August 10, 1995Date of Patent: November 10, 1998Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones
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Patent number: 5729822Abstract: A powder metal gear wheel having a core density of at least 7.3 g/cc, and in one embodiment 7.4 to 7.6 g/cc and a hardened carburized surface. A method of manufacturing transmission gears comprises, sintering a powder metal blank to produce a core density of between 7.4 to 7.6 g/cc, rolling the surface of the gear blank to densify the surface, and then heating the rolled sintered part and carburizing in a vacuum furnace.Type: GrantFiled: May 24, 1996Date of Patent: March 17, 1998Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones
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Patent number: 5711187Abstract: A gear wheel is formed from a pressed and sintered powder metal blank in which the metal powder comprises an admixture of iron powder and at least one alloying addition and the gear wheel is surface hardened by densifying at least the tooth root and flank regions to establish densification in the range of 90 to 100 percent of full theoretical density to a depth of at least 380 and up to about 1,000 microns.Type: GrantFiled: January 3, 1995Date of Patent: January 27, 1998Assignee: Formflo Ltd.Inventors: Christopher John Cole, Rohith Shivanath, Peter Jones
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Patent number: 5656787Abstract: A process of forming a sintered article for powder metal comprising blending carbon and ferro alloys and lubricant with compressible elemental iron powder, pressing said blended mixture to form sintering said article, and then high temperature sintering said article in a reducing atmosphere to produce a sintered article having a high density from a single compression.Type: GrantFiled: November 21, 1995Date of Patent: August 12, 1997Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones, Danny Thien Duc Thieu
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Patent number: 5641922Abstract: This invention relates to a process of forming a sintered article of powder metal comprising blending graphite and lubricant with a pre-alloyed iron based powder, pressing said blended mixture to shape in a single compaction stage sintering said article, and then high temperature sintering said article in a reducing atmosphere to produce a sintered article having a density greater than 7.4 g/cc.Type: GrantFiled: June 24, 1996Date of Patent: June 24, 1997Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones, Danny Thien Duc Thieu
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Patent number: 5552109Abstract: This invention relates to a process of forming a sintered article of powder metal comprising blending graphite and lubricant with a pre-alloyed iron based powder, pressing said blended mixture to shape in a single compaction stage sintering said article, and then high temperature sintering said article in a reducing atmosphere to produce a sintered article having a density greater than 7.4 g/cc.Type: GrantFiled: June 29, 1995Date of Patent: September 3, 1996Inventors: Rohith Shivanath, Peter Jones, Danny T. D. Thieu
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Patent number: 5516483Abstract: A process of forming a sintered article for powder metal comprising blending carbon and ferro alloys and lubricant with compressible elemental iron powder, pressing said blended mixture to form sintering said article, and then high temperature sintering said article in a reducing atmosphere to produce a sintered article having a high density from a single compression.Type: GrantFiled: February 8, 1994Date of Patent: May 14, 1996Assignee: Stackpole LimitedInventors: Rohith Shivanath, Peter Jones, Danny T. D. Thieu