Abstract. There are many potential applications for lightweight open-cellular metal structures, such as energy absorption, filtering, or thermal management. Such metallic open-cellular structures are often produced by additive manufacturing. Another option is the use of investment casting, for example by using open polymer foams as a template. By designing structures via Computer-Aided-Design (CAD), these can be used directly for additive manufacturing, either directly in metal or in wax as a template for casting. In this way the structure can be adapted very well to the needs, possible applications are shown in [1]. Using polymeric templates reduces the adaptability of the structure immensely. To use the full potential, it is necessary to develop the structure according to its future purpose. The 'ProZell' project is developing the basis for realizing such structures in high-manganese steels by investment casting using the lost wax process.