Influence of sintering atmosphere on properties of sinterhardened steels

The aim of this paper is to deepen the understanding of the influence of sintering atmosphere on the final properties of sinter-hardened steel components. A commercial Astaloy CrM powder has been uniaxially pressed in different shapes, identified in terms of area/mass index, with three different carbon additions (0.3 , 0.4 and 0.5 % w.) Sinter-hardening process has been conducted in a belt-furnace in order to re-enact industrial working conditions using six different protective / carburizing atmospheres. During the process, temperature profiles and atmospheres have been sampled and analyzed. Sintered samples have been analyzed in terms of oxygen contents, hardness and microstructure. Particular attention has been paid to the decarburizing/carburizing effect of different atmospheres in terms of composition and the resulting mechanical properties.