Untersuchungen der Verarbeitbarkeit des Schnellarbeitsstahls HS6-5-3-8 mittels Laser Powder Bed Fusion

The additive manufacturing process Laser Powder Bed Fusion (LPBF) has developed into series production in some areas, e.g. in turbomachinery construction and medical technology. Due to industrialization, there is also an increasing demand for the LPBF process for spare parts and small series in the tool industry in order to increase service life or shorten development times. Compared to conventional production, the integration of internal cooling channels or the use of lattice structures for light weight in conjunction with greater geometrical freedom are keys to the manufacturing of complex individual special design tools for the tool industry. It can therefore be deduced that the material selection for the LPBF process must be extended to include other tool steels. High-alloy, carbide-containing, abrasion-resistant tool steels such as high-speed steels are particularly suitable for use as cutting tools. However, high-alloy tool steels tend to crack during processing by LPBF due to internal stresses. In this work, the processability of high-speed steels is investigated using HS6-5-3-8 as an example based on different LPBF process designs. The aim is to fundamentally investigate the influence-effect relationships between LPBF process control (preheating temperatures), system technology (preheating and inert gas control), component number and component height, and chemical composition on the resulting defect density, microstructure and component hardness of HS6-5-3-8. The developed process control is to be used as a starting point for the manufacturing of a technology demonstrator. There maining challenges in processing high-speed steel HS6-5-3-8 by LPBF will be presented. The successful processability (large component density, crack-free specimens and homogeneous microstructure) when using pre heating temperatures ≤ 450 °C can be demonstrated.