| 摘要 |
PURPOSE: To produce a partially alloyed steel powder with which high-strength sintered parts are obtainable by low-temp. sintering at a low cost by uniformly mixing Ni powder with and sticking to a base iron powder uniformly mixed with a binder, then mixing and sticking Cu powder and MoO3 powder with and to this powder mixture and heating the mixture in a reducing atmosphere. CONSTITUTION: A binder is previously mixed uniformly with a base iron powder and 1.5 to 5wt.% Ni powder is added to this mixture and the mixture is uniformly mixed by a stationary vessel and rotary vane type high-speed mixing machine, by which the powder mixture is adhered to the base iron powder. On or more kinds of <=2wt.% Cu powder and 0.4 to 1.5wt.%, in terms of Mo, MoO3 powder are added to the mixture and the mixture is mixed to adhere these powders to the mixture and thereafter, the mixture is heated in the reducing atmosphere. The base iron powder is high-purity iron powder consisting of <=0.04wt.% Mn, <=0.003wt.% P and the balance iron with inevitable impurities. The Ni powder is preferably carbonyl Ni powder having the max. particle of <45μm and the average Fischer grain size of 3 to 5μm. As a result, the partially alloyed iron powder for powder metallurgy which yields the high-strength sintered parts by the low-temp. sintering at about 1130 to 1150 deg.C is obtd.
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