Prediction of particle size for water atomised metal powders: parameter study

Abstract

This work aims to investigate how some significant atomising parameters influence the mass median particle size d₅₀ of water atomised metal powders. More specifically, these were water pressure, melt flowrate, water jet angle, liquid metal viscosity and surface tension. Existing models for the prediction of d₅₀ during water atomisation were reviewed. The selected models were fitted and compared with atomising experiments of liquid iron containing 0·5–4·4%C. Experimental results and model calculations were used in a parameter study to investigate how the different parameters influenced d₅₀. The effect on d₅₀ was large for the water pressure, medium for the viscosity and low for the melt flowrate and surface tension. Model calculations indicate that the jet angle has a large effect on d₅₀, which should be verified by additional studies. The model proposed by Bergquist (B. Bergquist: Powder Metall., 1999, 42, 331–343) showed the best agreement with the current experimental data.

Keywords:

• Metal powder
• Powder metallurgy
• Water atomisation
• Modelling
• Particle size

The authors wish to thank H. Tegefeldt, M. Augustsson, M. Ohlsson and L. Boo for all their assistance during the atomising experiments. Thanks are also given to P. Johansson for the support and help during the metallographic investigation. B. Kaplan and E. Hervestad are also acknowledged for their participation in the initial part of the study.