Improving the surface quality of maraging 300 parts produced via laser powder bed fusion through powder distribution selection and optimized laser remelting

This work examines the impact of powder particle size distribution (PSD) on the surface finish of maraging 300 steel parts produced by laser powder bed fusion (LPBF). After an initial selection of two suitable powder raw materials, Mar 10-30 and Mar 15-45, the study demonstrates that finer powders lead to significantly smoother upfacing surfaces, with up to a 50 % reduction in surface roughness (Ra). The Mar 10-30 distribution not only produces superior surface quality but also allows for more advanced LPBF processing strategies. These strategies combine small layer thicknesses with laser remelting, demonstrating that top surface roughness can be reduced to as low as 1.5 mu m Ra. Finally, an outlook is given, suggesting that properly engineered powders, together with optimized LPBF processing parameters, enable the fabrication of both vertical single-track ridges or thin-walls down to similar to 100 mu m thickness and basic texturing patterns, offering a cost-effective insitu LPBF alternative to post-processing texturing. These developments open new possibilities for the surface finish and functionalization of LPBF components while increasing the precision and feature resolution in LPBF parts.