The spreading behaviour of stainless-steel powders for additive manufacturing

This work was aimed at linking single particle and bulk flow properties of Stainless Steel (SS316L) powders with their spreading behaviour for the additive manufacturing (AM) application. Two different batches of SS316L powders were investigated. It was found that both batches have identical particle size, morphology and some bulk flow properties (angle of repose, Hausner ratio, compressibility index and flow energy), however one of the batches did not consistently flow during Hall and Carney flow tests and also had very poor spreadability. The flow and spreading behaviours of the poorly spreading batch significantly improved and became identical to the good batch flowing drying in a vacuum oven and a freeze drying system. Further elemental analysis revealed that the poorly spreading powder batch had some dissimilar chemical compositions. This study revealed the complexity of defining a correlation between the powder properties and the spreading behaviour without considering the environmental conditions.