The Sintering Phenomena and Heat-Treated Properties of Carbides and Borides Precipitated P/M Alloys Made of H.S.S. Powder

The sintering phenomena of mixtures of high speed steel powder and boron containing ferrous alloy powders were studied to obtain carbides and borides precipitated wear resisting P/M alloys. Moreover, the properties of these alloys after heat treatment were also examined. AISI M7 and carbon reduced M7 (0.5%C) powders were selected, and Fe-B and Fe-Cr-B powders were used as additive powder. The results obtained were summarized as follows: (1) Fe-B alloy powder was better than Fe-Cr-B powder as the boron containing additive powder. (2) In order to get good mechanical properties, boron content of mixture was to be determined as (Mo at% +W at%)/B at%=1.0. (3) Carbon content of H.S.S. should be reduced from standard value to make carbides and borides coprecipitate.