Metal Additive Manufacturing Conference 2019

Additive manufacturing of steel powders gained in recent years a lot of attention. In the early stages of Laser Powder Bed Fusion (L-PBF) of steel powders the well-known materials 1.2709, 316L and 17-4 PH have been used due to their very low carbon content. However, since these materials are on the one hand quite soft (316L) and on the other hand in some cases too highly alloyed for specific engineering applications (1.2709), also carbon steels are increasingly considered for use in L-PBF processes. In general it is well known, that carbon limits the weldability of the steel materials. As a rule of thumb, steels with a carbon content below 0.22 wt.-% are suitable for L-PBF processes without powder bed preheating. Therefore, this work will present a new carbon-steel alloy concept which can be processed by L-PBF without powder bed preheating. Due to the special alloy design, it will be shown, that the printed parts are ready-to-use in the as-built state with a well-balanced property relationship of strength, ductility and impact toughness. Beside the usability in the as-printed condition, it will be presented, that an additional heat treatment or even a surface hardening process can be used to gain even better material and part properties compared to the as-built condition.