Effect of water atomization on properties of type 4130 steel processed by L-PBF

• Laser Powder Bed Fusion processed 4130 steels starting from gas and water atomized powders have been studied. Oxide-based inclusions were found within the steel matrix that activate ductile fracture during tensile testing. Micro-segregation of alloying elements was detected laser-processing both steels, which contributed to a local increase in microhardness. Water deliver comparable mechanical properties counterparts powder after tuning post-process thermal treatment. In current investigation, comparison between two type low-alloy produced by atomization, later Laser-powder bed fusion carried out. Samples fabricated showed relative density levels exceeding 99%, slightly lower than those achieved with powder. Both exhibited similar metallurgical features solidification, showing microstructure is mainly composed partially tempered martensite, bainite, retained austenite. Additionally, micro-segregation as-built microstructure, contribute The excess oxygen tended combine silicon form nano-sized SiO 2 inclusions. During laser processing, complex heating cooling effects generated adjacent tracks overlapping layers led an in-situ tempering fresh martensite. Accordingly, hardness values condition equivalent conventionally quenched samples at 350 °C 450 °C, for respectively. Finally, terms investigated atomization process resulted limited changes performance.