Abstract
In order to obtain spherical iron fines for the raw materials of the injection molding, atomizing conditions of molten iron were investigated by using the high pressre water atomizer developed at NRIM. The melt was atomized by the water jet with the velocity of 200m/s. The mean particle size measured with Coulter Counter was of 8μm. Carbon addition of 0.5% to the melt made the shape of powders spherical and increased the tap density ratio from 54% to 60%. Carbon in fine particles was easily removed by heating at 820K, 7.2ks in H2. Atomized powders of -20μm showed good sintering properties comparable to carbonyl powders having the same particle size at the temperature of 1520K. The mixture of iron powders and polyethylene wax of 6-7mass% had a suitable flow properties for the use of the metal injection molding. The shrinkage during sintering of dewaxed compacts was higher than that of compressed compacts.
