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 d 50 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 d 50 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 d 50 . The effect on d 50 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 d 50 , 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.

Water atomisation of metal powders: effect of water spray configuration

“…The magnitude of the pressure exponent 0.94 in Equation ( 2) compares well with values reported by others [3,6,8,14] which range between 0.6 and 1.2. The standard deviation SD, which represents the dispersion of the particle size distribution, does not change significantly with water pressure.…”

The Thermophysical Properties of Liquid TRIP/TWIP‐Steel Alloys Using the Maximum Bubble Pressure Method

“…Recently, a parameter study of d 50 particle size indicated that the viscosity has a stronger influence than the surface tension for water atomized metal powders. [7] Quested et al pointed out the relevance of the experimental values of the surface tension and density to spray forming. This study included a mathematical description of the high temperature atomisation process and the influence of the oxygen and sulfur steel concentration on the surface tension in the experimental trials was mentioned.…”

Influence of Liquid Metal Properties on Water Atomised Iron Powders

“…23) This model is presented in Eq. (13), with calculated exponents relevant for the present study ............. (13) where k is a model constant, α is the jet angle between the axis of the water jet and axis of the metal stream, DM is the melt stream diameter in m, mW and mM is the mass flow rate of water and metal respectively in kg s -1 .…”