This study aims at presenting a way to obtain nanostructured materials. Austeniticstainless steel (316L) nanopowders and ferritic/martensitic alloy steels (Fe14Cr) aresintered with the Spark Plasma Sintering (SPS) technique. This technique leads to a fullydense/nano-sized microstructure material after a short treatment. The optimal sinteringtemperature was found to be 850°C for both materials. The relationship between the Vickers Hardnessand scale of the microstructure is in good agreement with the Hall-Petch Law.