Influence of liquid metal properties on water atomised iron powders

Abstract

The main focus of the present study was the influence of liquid metal properties on the particle size during water atomisation. Experiments for liquid iron showed that alloy additions of carbon and sulphur decreased the particle size. Moreover, it was indicated that the reduced d50 value at increased %C and %S contents may be related to a decreased viscosity and surface tension respectively. An alternative mechanism could be that raised superheats at increased carbon contents increased the total available time for atomisation. This may also have decreased the particle size. The influence of surface tension and viscosity on the d50 value was further analysed with a theoretical d50 model proposed in a previous work. A reduced viscosity from 6.8 to 4.3 mPa s decreased the d50 value with 33%. In addition, the particle size was estimated to decrease with 27% by decreasing the surface tension from 1 850 to 900 mN m-1. © 2012 ISIJ.