Effect of gas pressure on conduit plasma atomization for fabricating spherical stainless steel powder

Abstract

In this study, spherical stainless steel powders are produced using the conduit plasma atomization. Parameters of the conduit plasma atomization process with gas variations of 1.5 bar pressure, 2 bar pressure, 2.5 bar pressure with 316L stainless steel raw material with a current of 25 Amperes, feed speed of 2 mm3/s. The results of stainless steel powders were observed using a digital microscope (Dino-Lite AM4115), scanning electron microscopy (SEM-FEI-Inspect F50), and energy dispersive spectroscopy (EDS). To ensure the purity of the resulting 316L stainless steel spherical powder, EDS was used for qualitative and quantitative elemental analysis. The results showed that the 316L stainless steel spherical powder particles varied in size from 35 µm to 140 µm, making them ideal for powders metallurgy application. The effect of gas pressure on the powder weight percentages for particle sizes 50 µm – 100 µm for 1.5 bar pressure, 2.0 bar pressure, and 2.5 bar pressure were 67.14%, 78.71%, and 81.73%, respectively. It is possible that this could happen because to break down molten metal into smaller size droplets, it is needed the kinetic energy of larger gas pressure. So that large gas pressure can produce more small particle size compared to small gas pressure.