Particle size distribution is an important powder characteristic as it directly influences the powder properties and, therefore, the final powder material. For powder materials manufactured by hot isostatic pressing (HIP), HIP-capsule filling is a crucial step where the particle sizes will influence the packing density, as well as the flow properties and the segregation tendency of the powder. In this study, the particle size distribution of gas atomised steel powders was measured by sieving and laser diffraction. However, some uncertainty exists regarding what is actually measured by the two different methods. To clarify this, automatic image analysis of the powders was performed as a comparison. The measuring principle of both sieving and laser diffraction is optimised for spherical particles. Any shape deviation from a sphere, such as elongation or satellites, was found to have a different influence on the results produced by the two methods.
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