PHYSICAL BEHAVIOR OF WATER-ATOMIZED IRON POWDERS - PARTICLE-SIZE DISTRIBUTION AND APPARENT DENSITY

A series of apparent density measurements was performed on a water-ato mized iron powder and several synthetic blends produced by mixing spec ific size fractions of the original powder. The Hall flowmeter and Arn old Density Meter instruments were employed in this study. The ability to reconstitute the original iron powder from various amounts of its size fractions was demonstrated by the agreement between apparent dens ity measurements, especially those of the Arnold Meter, for a reblend and the as-received iron powder. Removal of either the <38mum or >150m um fractions from the original powder, individually, had the effect of lowering the apparent density. Withdrawal of both size fractions caus ed an even more pronounced decline in this property. This effect is in terpreted in terms of the round <38mum particles filling the caverns a vailable within the irregularly shaped >150mum particles. Removal of t hese extreme powder fractions, either individually or collectively, pr oduces less particle interaction and thus a lower AD. Comparisons of e xperimental AD results to those calculated using a reference relation offer some support for the results of this study.