Process Development of Grade A11 High Carbon Tool Steel for Metal Binder Jetting

Grade A11 (X245VcrMo8-5-1) tool steel is one of the most commonly used tool steels for cold work applications as its high carbide content makes it highly wear resistant. However, its total carbon content of 2.5 % also leads to challenges in shaping by additive manufacturing, especially for LPBF. With its homogeneous temperature distribution during the consolidating sintering step, metal binder jetting (MBJ) capable to process a wide range of materials, including difficult-to-weld materials. This research focuses on the process development for grade A11 tool steel using MBJ. After the development of suitable printing parameters considering layer thickness and recoat speed, the sintering behaviour is investigated in detail. Initial sintering parameters are determined by thermoanalytical measurements. Subsequently, the impact of different sintering temperatures and atmospheres on the microstructural evolution are presented. Finally, it is shown that complex applications can be manufactured true to size and fully dense with the parameters determined.