Feasibility investigation for laser powder bed fusion of high-speed steels

Laser powder bed fusion (LPBF) is an additive manufacturing (AM) process used in many areas - the aerospace, automotive as well as medical technology - with various metals such as nickel-, aluminum- and titanium-based alloys. But the mechanical engineering industry need wear-resistant steels with high hardness, like high-speed steels, in combination with the advantages of LPBF: high geometrical complexity and high degree of individualization. However, when processed with LPBF, these steels often form cracks, making the process therefore challenging to handle. In this feasibility investigation, we demonstrate that building up dense and crack-free specimens made from high-speed steel HS 6-5-3-8 (carbon content > 1.3 wt.-%) with LPBF is possible by preheating the base plate to 500 °C. The specimens reach a hardness of over 60 HRC (as built). Furthermore, the influence of the LPBF process parameters on the microstructure of these specimens is evaluated.