Abstract
Maraging steels are good candidates for the laser powder bed fusion process (L-PBF), also known as Selective Laser Melting, due to excellent weldability and resistance to quench cracking. Powders physical and chemical characteristics dominate the final microstructure and properties of the printed parts, that are also heavily influenced by the process parameters. In this study, the effects of the scanning strategies on dimensions, average surface roughness, density and material hardness were evaluated, keeping the powder type and the volumetric energy density (Andrew number) constant. The effects of the scanning strategy on these properties are far less understood than on other important ones, like residual stresses and distortion, strongly affected by the scanning strategy. In this study, parallel stripes, chessboard and hexagonal pattern strategies were studied, keeping the Andrew number constant but varying the interlayer rotation. In general, the hexagonal strategy underperformed compared to the chessboard and the stripes ones.
Highlights
It is possible to notice that the hexagonal strategy almost always led to the highest average surface roughness values, while the chessboard strategy almost always led to the lowest average surface roughness
This work aimed to investigate the effect of scanning strategy and the main process parameters on the 18Ni300 maraging steel parts produced through the laser powder bed fusion (L-PBF) process
The volumetric energy density (Andrew number), the laser power and the layer thickness were kept constant so scan speed and hatch spacing changed in a dependent way
Summary
Effect of Energy Input in L-PBF Processing. Maraging steels are good candidates for the laser powder bed fusion (L-PBF) process because of the excellent weldability, resulting from the lack of interstitial alloy elements, and the resistance to quench cracking, resulting from the low carbon content. The microstructure of the L-PBF produced parts depends on the powder chemical composition and properties, but it is mainly related to the values of the process parameters used to print. In the model of the L-PBF process, the laser acts as a moving Gauss heat source, leading to multi-mode heat and mass transfer [1]. There are many models to define the amount of energy delivered by the laser to the powder bed, trying to characterize the process conditions [2].
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