With the process of desulphurization of hot metal-basic oxygen furnace-LF refing-vacuum degassing (VD) /RH treatment-continuous casting (CC), the yield is not closely related to the grade of steel, fluctuation of sulfur and oxygen content after add the rare earth, but it is strongly related to the type of processes. The effects of rare earth on denaturation of inclusions in steel are different for different steel grades. However, after add rare earth, the size of inclusions in steel decreases and their distribution becomes more dispersive so that the fatigue and impact performances are improved. The welding performance of steel plate after add rare earth is improved by delaying the formation of upper bainite and inhibiting the growth of austenite grains during welding.

rare earth steel  /  continuous casting process  /  microalloying  /  oxide metallurgy