Evolution of Mechanical Properties and Microstructure in Q&P Processed Unconventional Medium-Carbon Silicon Steel and Comparison between Q&P Processing, Quenching and Tempering, and Austemperingfor

This paper investigates the evolution of microstructure and its related mechanical properties of Q-P processed medium-carbon AHSS steel. The investigated informations were compared to the structures and mechanical properties of quenched and tempered, austempered specimens made of the same steel grade. According to the correlations between observed microstructures after Q-P, quenching and tempering, austempering the presence of bainite in Q-P processed specimens was found. The hypothesis of bainite growth durinq Q-P processing was devoleped. The experimental results show that during Q-P heat treatment the bainite transformation can occur even when the partitioning temperatures are below the temperature Ms of experimental steel.