Kyoung-Mook Lim

Influence of reducing gases on the reduction behavior of water-atomized Fe-Cr-Mo powder

In this study, Fe-based powder of composition Fe-3 wt% Cr-0.5 wt% Mo was prepared using a water atomization process. After atomization, the total oxide content of the powder was calculated as ca. 2.09 wt%. Gas reduction of the as-atomized powder using CO, CH4, and H2 gases was carried out in a horizontal vacuum tubetype furnace at 900 °C. Thermodynamic and kinetic calculations for the reduction reactions were carried out using FactSage and HSC Chemistry programs. The results showed that the reduction proceeded in two stages: from Fe3O4 to FeO, and finally to Fe. Each reducing gas was evaluated and compared based on the oxide reduction capability. The lowest oxygen content was achieved for CH4 (0.49 wt%). However, with CH4, cementite (Fe3C) was also detected due to cracking of CH4.