RECENT DEVELOPMENTS IN FERROUS POWDER-METALLURGY ALLOYS

A systems approach to engineered ferrous powder metallurgy (P/M) mater ials is described. The approach encompasses the use of highly compress ible, high performance powders in premixes produced using proprietary mixing technology that employs patented binders. To ensure that an app ropriate microstructure is achieved to suit the functional requirement s of a particular application, alloys are formulated based on a knowle dge of the compaction and sintering cycle that will be used to make th e P/M parts. These premixes have improved flow and die filling charact eristics that result in greater consistency throughout the entire P/M part manufacturing process. In addition, the use of binder treated pre mixes leads to reduced dusting and segregation of alloy additions. Bin der treated premixes produced using highly compressible, prealloyed mo lybdenum steel powders are shown to be particularly well suited for qu ench-hardening, sinter-hardening, and high temperature sintering. They also form the basis for a series of chromium, manganese, and chrome-m anganese P/M steels. The systems approach will be augmented during 199 4 by the introduction of new material and process technology that enab les part densities of 7.3 to 7.5g/cm3 to be achieved through single co mpaction processing.