Patent ID: 6696014
Filing Date: 2004-02-24
Classification: B22F,C22C

Abstract:
A method of producing an iron-based sintered powder metal body comprising the step of:mixing at least, an iron-based powder consisting of, at most about 0.05 mass % of carbon, at most about 0.3 mass % of oxygen, at most about 0.010 mass % of nitrogen, and remainder being iron and inevitable impurities, and graphite powder of at least about 0.03 mass % and at most about 0.5 mass % based on the total weight of the iron-based powder and the graphite powder, and optionally, lubricant of at least about 0.1 weight parts and at most about 0.6 weight parts based on 100 weight parts of total weight of the iron-based powder and the graphite powder, resulting in iron-based powder mixture, compacting said iron-based powder mixture into a preform the density of which is about 7.3 Mg/m3 or more, and preliminarily sintering said perform in a nonoxydizing atmosphere in which partial pressure of nitrogen is about 30 kPa or less and at a temperature more than about 1000Â° C. and at most about 1300Â° C.