Effect of cerium addition on microstructure and mechanical properties of as-cast high grade knives steel

The carbides and mechanical properties of as-cast high grade knives steel with and without cerium(Ce)addition were studied.The as-cast microstructure of the steel,the size of carbide precipitation,carbide morphology,and mechanical properties were systematically studied through optical microscopy,scanning electron microscopy,and X-ray diffraction.Besides,through the Equilib module of the FactSage thermodynamics software,the changes in the precipitation type of the inclusions with Ce during the solidification of the steel were calculated.The results indicate that the rare earth Ce is added into the steel to refine the as-cast microstructure of the steel.The types of inclusions in the steel are changed by the addition of Ce.The precipitated carbide morphology changes from a complex rod shape to a relatively single lamellar shape.The rare earth inclusions formed in steel by a moderate addition of Ce can be severed as the core of heterogeneous nucleation of carbides,which reduce the size of carbide precipitation,promote the uniform distribution of carbide in the as-cast steel,and improve the mechanical properties of the as-cast high grade knives steel.