稀土对重轨钢冲击韧度的影响作用机制

通过实验测定、金相观察和理论分析，研究了稀土对重轨钢冲击韧度的影响作用机制. 随着稀土加入量的增加(0~0.06%, w)，重轨钢中的固溶稀土含量均先逐渐增大，达到一定值后开始减小. 当稀土加入量为0.01%时，重轨钢的奥氏体晶粒尺寸明显细化，冲击韧度显著改善. 稀土在改善重轨钢冲击韧度的同时，可以减小横向冲击功和纵向冲击功之间的差距，消除钢的各向异性，增强钢的各向同性. 在本实验条件下，最佳稀土加入量为0.01%.

Mechanism and Effect of Rare Earth on the Impacting Toughness of Heavy Rail Steel

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.