铈在重轨钢中行为特性的热力学模型分析

Model Analysis on Behavior of Cerium in Heavy Rail Steel

以重轨钢为研究对象,建立可以定量描述稀土在重轨钢中行为特性的热力学模型,并通过实验验证了模型的精确度。利用该热力学模型,研究分析了在不同氧、硫的质量分数条件下,铈加入量对重轨钢液及其凝固过程中铈的赋存状态以及夹杂物组成的影响作用规律,得到以下结论:当钢中氧、硫的质量分数较低时,随着铈加入量的增加,Ce2O2S的析出量略有减少;当钢中氧、硫的质量分数较高时,随着铈加入量的增加,Ce2O2S的析出量有所增加;铈加入量的增加以及温度的下降均有利于CeS的析出;当钢中氧、硫的质量分数较低时,在凝固过程中钢中析出CeN和固溶铈;随着铈加入量的增加,CeN的析出温度和析出量均有所增加,当CeN的析出达到平衡时,固溶铈大量析出。

Thermodynamic model which quantificationally described the behavior of rare earth in heavy rail steel was proposed. It was shown from the experiments that the model was very precise. The effects of the addition of Ce on the state of RE and constitutes of inclusions were studied with different mass fraction of oxygen and sulfur. When the mass fraction of oxygen and sulfur are low, with the Ce addition increased, the precipitation content of Ce2O2S inclusion is decreased. When the mass fraction of oxygen and sulfur are high, it is increased with the increment of Ce addition.The increment of Ce addition and the decline of temperature are all good for the separation of CeS inclusion. When the mass fraction of oxygen and sulfur are low, Ce solute and CeN are precipitated during the solidification process. With the Ce addition increased, precipitation content and temperature of CeN are all increased. Ce solute is precipitated largely after the separation of CeN achieved equilibrium.