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US 4,050,932 AGranted
Colloidal graphite forging lubricant and method
AssigneeGeneral Motors Corporation
InventorHarold G. Lemmer
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AssigneeGeneral Motors Corporation
InventorHarold G. Lemmer
Estimating the term…
An improved colloidal graphite hot forming lubricant and hot forming process for high density ferrous powdered metal articles using this lubricant. Extremely fine powdered copper is included in an otherwise conventional colloidal graphite hot forming lubricant. High quality, including high density, ferrous metal articles are produced by coating a ferrous powdered metal preform with this lubricant, presintering the coated preform at a higher temperature of 2100.degree. - 2500.degree. F. for a short time by induction heating, allowing the presintered preform to cool to a desired hot forming temperature below 2000.degree. F., and then hot forming the preform in the usual manner. Lubricant-preform interaction at the higher temperature is precluded, making long presintering times and special presintering equipment necessary.
A method for hot forming highest quality ferrous powdered metal articles without a prior separate presintering operation, said method comprising the steps of:
A method of hot forming a ferrous powdered metal article that includes concurrent presintering of a ferrous powdered metal preform during the same heating operation and with the same induction heating equipment used to heat presintered ferrous powdered metal preforms to hot forming temperatures,
Dependencies are inferred from the claim text.