Influence of Oxygen Concentration in Building Environment and Oxidation Extent of Maraging Steel on Spatter Generation Behavior in Powder Bed Fusion

Abstract

This study investigated the influence of oxygen concentration in the building environment and the degree of oxidation of maraging steel powder on spatter generation behavior during powder bed fusion (PBF) process. The powders were oxidized at various heat treatment temperatures, and their degree of oxidation was evaluated using Auger electron spectroscopy. The spatter generation behavior of the powders at oxygen concentrations of 1.0×102 ppm (99.99% purity) to 5.0×104 ppm (95% purity) in the building atmosphere was then investigated. The results indicated that the presence of oxygen in the building environment had a greater effect on spatter generation than the oxide film on the maraging steel powder. The oxygen concentration affected the velocity and angle of spatter particles. At an oxygen concentration of 5.0×104 ppm, the number of spatter particles was 2.5 times greater than that of 1.0×102 ppm. A higher oxygen concentration resulted in an increase in the number of fume particles adhering to the spatter surface, reducing its reusability. The oxide film on the powder did not significantly affect the vapor jet behavior, but it altered the powder’s flowability, impacting the spatter generation. To decrease spatter generation and obtain a high-quality spatter surface, it is recommended that the oxygen concentration in the building environment should be maintained at 1.0×102 ppm.