Effect of Oxide Particles on Microstructure and Mechanical Properties of the 45 Carbon Structural Steel

Striking difference in density between the oxide and the steel results in difficulty in preparing oxide dispersion strengthened steel with large size parts or materials. In this research, Al₂O₃ and TiO₂ particles were initially milled with the 20 steel, and then the mixture was heated to a molten state to form a master alloy, which was used as a raw material for further preparation of the object steel. It was found that homogeneous distribution of the oxide particles was obtained in the mass production of the steel. Moreover, the obtained 45 carbon structural steel presents fine microstructures, together with improved mechanical properties, especially the impact ductility. This should be attributable to the transformation from the introduced micro-size oxide particles to the nano ones, which act as heterogeneous nucleants that play an important role in grain refinement and dispersion strengthening for the steel, during the remelting of the master alloy.