Manufacturing and Optimization of Maraging Steel Fabricated by the Laser Powder Bed Fusion (LPBF) Technique

Laser powder bed fusion (LPBF) is used as an additive manufacturing (AM) technique to fabricate complex structures. In this study an orthogonal response surface test was designed to optimize the relative density of an 18Ni300 maraging steel sample fabricated through LPBF. The results demonstrated that the influence of the process parameters on the relative density of the maraging steel sample decreased in the order of laser power > scanning speed > hatch spacing. At a laser power of 150 W, scanning speed of 793.658 mm/s, and hatch spacing of 65 mu m, the relative density of the sample was 99.797%, which was consistent with the theoretical relative density of 99.80% predicted by the multivariate linear binary regression model and higher than the relative density of 99.13% optimized through the orthogonal test. The ultimate tensile strength of the sample was 1.43 GPa, which is higher than that optimized through the orthogonal test. In addition, the surface of the sample was smoother and flatter, the melt track more continuous and regular, and the pores fewer in number as compared to unoptimized sample.