Abstract
The influence of the packings on the dimensional accuracy of the sintered machine parts is studied. Detailed discussion covers the problems of the influence of the bulk density on the green density and the plastic strain energy. In the experiments the rubber press method which is one of the hydrostatic press methods is adopted in order to compact the powder uniformly.
The scattering of the bulk density exerts influence on the dimensioal accuracy of the sintered machine parts. The green compacts of the density 5.3g/cm3 compacted from the powder of the bulk density 2.7-3.5 g/cm3 result in the dimensional changes of 0.48-0.34% after sintering, and the green compacts having the same strain energy (W=30 kg.mm/mm3) result in the dimensional changes of 0.52-0.29% after sintering. Under the same compressive stress, as the bulk density increases, the green density increases and consequently the dimensional change decreases after sintering. In compacting the green compacts having the same density, as the bulk density increases, the plastic strain energy decreases and after sintering the dimensional change decreases.
