中文摘要：

根据钢液凝固时元素的固-液界面的偏析，并结合溶质元素在固、液相中的有限扩散，建立了钢液凝固过程中微观偏析和钛氧夹杂生成的耦合模型，模型计算表明：由于钛氧夹杂的生成，凝固过程中溶质元素的微观偏析程度得到较大抑制；控制适当的氧含量，有利于夹杂物均匀分布；随着冷却速率的增加，夹杂物数量增加，尺寸变小，当控制在目前薄板坯条件下，半径为0．58μm、含量为10^-5量级的夹杂物可弥散分布于钢中，有利于性能的改善。

英文摘要：

Based on the segregation of solute elements at solid-liquid interface, a coupled model of microsegregation and Ti-O inclusion precipitation during solidification of liquid steel is established by considering the finite diffusion of solute elements in both liquid and solid phases. The calculation results show that the segregation degree of solute elements is suppressed greatly due to the precipitation of Ti-O inclusions during solidification. The inclusions can be uniformly dispersed in steel by controlling appropriate oxygen content in liquid phase. The amount of oxides increased and their size reduced with increasing cooling rate. The radius and amount of the oxides only reached 0.58 μm and 10^-5 order, respectively, under controlling the condition of thin slab caster at present. These oxides are uniformly distributed in steel, which is helpful to improve steel properties.