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Powdered Iron Composition

IP.com Disclosure Number: IPCOM000092303D
Original Publication Date: 1968-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Jordan, EF: AUTHOR

Abstract

Sintered iron, having low percentages of copper and nickel, show significant increases in tensile strength and ductility upon repressing and aging. Iron powder is mixed with 1-2% of -325 mesh copper, 1% nickel powder and a suitable briquetting lubricant. After briquetting, the material is sintered above 2000 degrees F in a furnace atmosphere of dissociated ammonia or hydrogen. Following this treatment, the material is repressed to final size and minimum density of 7.5 grams/cma. Repressing results in an increase of ultimate tensile strength of approximately 20% and a decrease in ductility of approximately 50%.

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Powdered Iron Composition

Sintered iron, having low percentages of copper and nickel, show significant increases in tensile strength and ductility upon repressing and aging. Iron powder is mixed with 1-2% of -325 mesh copper, 1% nickel powder and a suitable briquetting lubricant. After briquetting, the material is sintered above 2000 degrees F in a furnace atmosphere of dissociated ammonia or hydrogen. Following this treatment, the material is repressed to final size and minimum density of 7.5 grams/cma. Repressing results in an increase of ultimate tensile strength of approximately 20% and a decrease in ductility of approximately 50%.

After repressing, the material is heated in a protective atmosphere to approximately 1000 degrees F for 2 hours. This final aging treatment increases tensile strength approximately 20% beyond the strength achieved from repressing. Ductility is improved with an increase in elongation of approximately 50%.

The copper improves strength by the mechanism of precipitation hardening. The nickel counteracts growth during sintering and permits utilization of a single die for briquetting and repressing. Dimensional change during the aging treatment is less than .0001 per inch. The alloy is therefore suitable for manufacture of precision parts with strength and toughness requirements beyond that achieved with unalloyed iron.

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