| 摘要 |
PURPOSE:To obtain sintered high speed steel showing extremely excellent cutting property and tool properties, by compounding a fine powder consisting of carbide, nitride and carbonitride of Ti in a high speed steel fine powder being a stock material powder prepared by heating and reducing treatment in the titled preparing method. CONSTITUTION:A metal oxide fine powder and a carbon fine powder are compounded in an iron oxide fine powder so as to have a predetermined high speed steel composition after reduction. This compounded powder is reduced under heating in a H2-atmosphere to obtain a stock material powder. This reduced powder is crushed to obtain a high speed steel fine powder having an average particle size of 10mum or less. In the next step, a fine powder comprising one or more of carbide, nitride and carbonitride of Ti is added to and mixed in the obtained fine powder in a ratio of 1-10wt%. This stock material powder mixture is press molded to form a green compact which is, in turn, sintered at 1,100-1,300 deg.C in a reducing gas atmosphere or in vacuum to obtain a sintered substance having a theoretical density ratio of 95% or more.
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