Cracking susceptibility of maraging parts manufactured by laser powder bed fusion additive manufacturing: Study on the powder characteristics and baseplate preheating influence

Abstract

Maraging steel 300 processed by laser powder bed fusion (PBF-LB/M) is widely used for manufacturing inserts and moulds with conformal cooling channels. For such applications, high fracture toughness and strength are required to withstand thermal fatigue and any defect like pores, lack of fusion and cracks should be avoided so that the durability of the mould is not reduced. Maraging steel is prone to be cracked due to thermal gradients which arise during PBF-LB/M. Moreover, it was recently observed that slight variations in composition led to the crack's presence, which implied lower mechanical properties. In this study, two powder batches, from the same powder producer, were employed with the same processing parameters. The effect of small changes in minor elements composition of the powder batch on cracking was studied and the preheating temperature was varied to significantly reduce the crack density. The presence of cracks significantly reduced the ductility of the parts.