Mechanism and Effect of Rare Earth on the Impacting Toughness of Heavy Rail Steel
稀土对重轨钢冲击韧度的影响作用机制

The mechanism and effect of rare earth (RE) on the impacting toughness of heavy rail steel have been studied by means of experimental measurement, microscopic structure observation and theoretical analysis. Under the experimental conditions, the content of RE solute in heavy rail steel first increases and then decreases with the RE addition increasing. When the content of RE addition is 0.01%, the grain size of austenite can be obviously fined, and the impacting toughness of heavy rail steel can be obviously improved. RE in the steel can decrease the difference between the transverse impact energy and the longitudinal impact energy, eliminate the anisotropism and increase the isotropy of heavy rail steel. The optimum mass fraction of RE addition is 0.01% for heavy rail steel.