Advances in Maraging Steels for Additive Manufacturing

Maraging steels such as 1.2709 are high strength—high toughness alloys that gain their exceptional mechanical properties by the combination of nanometer-sized intermetallic precipitates and a martensitic matrix. Here the martensitic microstructure is not achieved by a high carbon content but by adding nickel to the chemical composition. In turn, the lack of carbon leads to good weldability and therefore makes these materials preferred candidates for additive manufacturing techniques, such as selective laser melting (SLM). Applications for SLM produced components are found especially in the tooling industry, where the implementation of inserts with intelligent conformal cooling channels in dies and moulds has already shown to drastically increase the tool lifetime. In this study, different maraging steels are investigated with respect to typical powder characteristics, such as sphericity, particle size distribution, on the one hand, and the microstructure as well as the achieved mechanical properties of the respective SLM printed parts, on the other hand.