Comparative analysis of gas atomised and recycled 316L stainless steel powders for Binder Jetting

In our work, we investigate the suitability of a 316L stainless steel powder from scrap metal recycling for binder jetting and the results are compared to those obtained for a gas atomised feedstock. First, the main morphological features of the particles, in particular sphericity and size distribution, are measured by static image granulometry and scanning electron microscopy. Then, the dispensing rate and the printer deposition parameters are optimised to obtain a smooth and homogeneous powder bed. After printing, the building box is cured at 180 °C to consolidate the green components, whose density and geometrical accuracy are determined by caliper measurement. Finally, the microstructural and mechanical properties of the vacuum sintered specimens are studied. Phase composition is determined by x-ray diffraction and microscopy, with specific attention to δ-ferrite formation at the grain boundary. Hardness is evaluated by Vickers micro-indentation and compared to typical properties of 316L by conventional manufacturing.