Modification of Liquid Steel Viscosity and Surface Tension for Inert Gas Atomization of Metal Powder

Inert gas atomization is one of the main sources for production of metal powder for powder metallurgy and additive manufacturing. The obtained final powder size distribution is controlled by various technological parameters: gas flow rate and pressure, liquid metal flow rate, gas type, temperature of spraying, configuration of nozzles, etc. This work explores another dimension of the atomization process control: modifications of the liquid metal properties and their effect on the obtained powder size. Series of double-alloyed Cr-Mn-Ni steels with sulfur and phosphorus were atomized with argon at 1600 °C. The results indicate that surface tension and viscosity modifications lead to yielding finer powder fractions. The obtained correlation is compared with the individual modification of surface tension with S and Se and modification of viscosity with phosphorus. Discrepancy of the results is discussed. Additives of surfactants and viscosity modifiers can be a useful measure for powder fractions control.