Abstract
Solid-liquid separation behaviors of grinding sludge of alloy steel (SCM440) were investigated by measuring water contents of green compacts obtained by compression tests. The sludge was easily compressed by low stresses in the initial stage of the compression because of its fibrous particle-shape. But in more advanced stage, decreasing rate of the water contents dropped significantly because of its high strength. Differences between heights after rejection and heights before unloading, namely spring backs, were very large; roughly from 35% to 45%. As the spring back leads to re-absorption of the water during the unloading after the compression, some measures for preventing the re-absorption must be applied to in the practical uses.
Furthermore, in order to investigate these compacting behaviors in wider range of properties of the particles, three kinds of commercial -use powders (Fe, Cu, and Al) were also tested together with the sludge. It was clarified that the water contents had a good correlation with the ratios of the compacting pressures to the yield stresses, and the deviations from the correlation curve were explained to occur due to the influences of the shape and the dimension of the particles.
