Influence of some factors on the powder densification process

Abstract

1. The limiting stressed state of powder materials is described by a linear function known as “Coulomb's flow criterion.” 2. It is demonstrated that, in stress-distribution determinations, powder materials may be analyzed from the viewpoint of the continuity hypothesis. 3. Compared with machine oil, zinc stearate produces a more marked decrease in the strength parameters of a material and gives a greater density gain in pressing at the constant pressure. 4. Additions of more than 0.25 wt.% zinc stearate have no effect on the shear-strength characteristics of powder materials (ϱ and K) and produce no further lowering of compaction pressure. 5. Experiments on the hydrostatic pressing of powders and mixtures established the same character of variation for the shear-strength parameters and density of the materials investigated.