Production of Fe-C alloys through reduction and sintering of cementite powders in hydrogen gas atmosphere

In recent years, it has become important to reduce emission of CO ₂ from the iron and steel making process in terms of preserving ecological environment. Cementite is recognized as a new iron resource because there is no CO₂ emission on the reduction of cementite to iron. In this study, a new steel making process through reduction and sintering treatment of cementite powder was proposed, and microstructure of the material obtained by this process was examined by scanning electron microscopy and EBSP analysis. The cementite powder obtained by mechanical alloying technique was compacted and then subjected to the reduction and sintering treatment in H₂ gas atmosphere at 1073-1273K in order to obtain bulky steel materials. The relative density of sintered material became 95% or more when the sintering was performed at 1173K. The sintered material has ferrite-pearlite structure of the grain size of around 5 μm. This result demonstrates that the reduction and sintering of cementite is one of useful methods to fabricate fine-grained steel without CO₂ emission.