Laser Powder Bed Fusion Of High Carbon Tool Steels

Tool steels are martensitic steels alloyed with carbide forming elements, thus having high strength, hardness and wear resistance. These characteristics, however, make them costly materials to shape into complex geometries. Laser powder bed fusion (PBF-LB) enables the consolidation of near-net-shape complex shapes from powders, which is a highly resource efficient way of producing tools. However, processing tool steels with PBF-LB is problematic due to hardening and segregation generated during the process leading to high stresses and eventually to cracking. To diminish these problems, we utilized a tailored high temperature building platform in PBF-LB to process gas atomized high carbon tool steels such as K110, S600 and 1.4122. Calphad method was used to evaluate the stress formation and cracking tendency of these alloys. The microstructure, hardness and tendency to form residual stresses of the manufactured samples were characterised. Properties comparable to conventionally manufactured quenched and annealed tools steels were achieved