Vacuum Sintering Studies On Chromium Alloyed PM Steels

Recent advancements in vacuum furnace technologies have led to an increased interest in vacuum sintering of Powder Metallurgy (PM) steel components owing to the robustness, productivity and the possibility to integrate heat-treatment into the process at an attractive cost. In the present study the potential for vacuum sintering of chromium-alloyed PM steels and the effect of the vacuum level on the final properties of the components is evaluated. The studies were performed on Fe-1.8 wt.% Cr powder and the sintering experiments were performed in a dilatometer. Four different vacuum levels: 1, 10, 10-2 and 10-4 mbar were studied and the effect of density and carbon content were also examined. The results indicate an efficient oxide reduction and process robustness at intermediate vacuum levels whereas high-temperature sintering in high vacuum brings risk of Cr-sublimation. Still, applying proper conditions, vacuum sintering proved to be an attractive alternative to process Cr-alloyed steel powders. The influence of vacuum level on the sintering efficiency of chromium-alloyed PM steels is studied.