Methods for sintering powder metallurgy parts
AssigneeAirco, Inc.
InventorHarbhajan S. Nayar
Life of this patent
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Abstract
Steel powder metallurgy parts having approximately 0.2 to 10% carbon in the form of graphite and approximately 1% lubricant are sintered in the hot zone of a furnace under temperatures of approximately 2050.degree. F for periods of up to approximately 1.0 hour under an atmosphere comprised of at least 90% nitrogen, up to 9.75% hydrogen and carbon monoxide with a maximum 5% carbon monoxide, 0.25-2.0% methane or equivalent hydrocarbon and a dewpoint of the mixed atmosphere of less than -60.degree. F.
Claims7
A process for sintering carbon steel powder metallurgy parts having a density of less than 90% theoretical maximum density and 0.3 to 1.3% carbon in the form of graphite in the hot zone of a sintering furnace comprising the steps of heating said hot zone to a temperature of at least 2000.degree. F, passing said parts through said hot zone while supplying to said hot zone an atmosphere comprised of the following constituents by volume:
- at least 90% nitrogen, up to 9.75% hydrogen and carbon monoxide with said carbon monoxide comprising 5% or less of said atmosphere, 0.25-2.0% gaseous hydrocarbon and having a dewpoint of -60.degree. F or less.
Dependencies are inferred from the claim text.