The achievable mechanical properties of SLM produced Maraging Steel 300 components

Selective laser melting (SLM) is a process that produces near net shape parts from metallic powders. A concern with SLM-produced metals is the achievable materials performance with respect to mechanical properties. Particularly, three important aspects strongly affect the mechanical properties of the material: internal stresses resulting from steep temperature gradients and high cooling rates, the resulting microstructure and the occurrence of pores and flaws.

This paper presents SLM-produced maraging steel 300 (18Ni-300), an iron-nickel steel alloy often used in applications where high fracture toughness and strength are required. The steel’s achievable tensile, crack growth and hardness properties and the manner in which these compare to the wrought counterpart are reported. In addition, this paper investigates the porosity distribution and achievable density, residual stress levels and post-processing procedures using heat-treatments.

It is found that tensile properties, hardness and microstructure compare well to its wrought counterpart. Fatigue growth rates are also comparable, though they are influenced by residual stresses and microstructure.

The investigation into the mechanical performance addresses two issues: the achievable mechanical properties and the understanding of the link between the manufacturing process and the achievable material performance.