Effect of Powder Recycling on the Surface and Selected Technological Properties of M300 Maraging Steel Produced via the SLM Method

This study delves into selective laser melting (SLM). By using M300 steel in virgin and recycled powder form (after 20 cycles), with the aim of reducing the cost of printing for the practical application of M300 maraging steel, a comprehensive comparison between the two types of powder was evaluated. The powder’s morphology was analyzed using scanning electron microscopy (SEM) and backscattered electrons (BSE). The particles were seen to have a spherical shape, with a notable number of satellites attached to their surfaces. The particle size distribution (PSD) was examined and ranged from 10 to 90 µm for both powders. In addition, the porosity exhibited an average value of 0.07% for the virgin powder and 0.10% for the recycled powder. The microstructure was examined. Additionally, the surface wettability was tested, and it was seen to display wetting behavior for both types of powder, while blackened surfaces showed a higher wetting angle than untreated surfaces (hydrophobic). The 2D roughness measurements showed that the recycled powder had no significant difference from the virgin powder (Ra = 5.33 µm, Rz = 24.17 µm) before blackening and (Ra = 5.48 µm, Rz = 24.07 µm) after blackening. Corrosion tests proved that the recycled powder did not affect the corrosion properties of the material, while blackening caused partial surface corrosion in both types of samples, regardless of the used powder.