论文部分内容阅读
根据过共析钢(特别是碳质量分数为0.90%~0.95%的钢种)凝固过程氮钛元素的溶质再分配机制,对钢中TiN夹杂的形成进行热力学计算。结果表明:随着钢中碳质量分数的增加,在凝固前沿液相形成TiN夹杂所需的氮钛浓度积逐渐降低,同时各钢种都是在凝固后期(固相分数在90%以上)达到形成TiN夹杂的热力学条件。在最后凝固区域,由于钢液补缩不充分,钢的组织出现不同程度的疏松,造成TiN夹杂与钢坯疏松共存的现象。为控制碳质量分数为0.90%~0.95%的钢种中的TiN夹杂,需要进一步降低凝固前沿液相中氮钛浓度积。
According to the solute redistribution mechanism of the nitrided titanium during the solidification process of hypereutectoid steel (especially the steel with 0.90% ~ 0.95% carbon content), the formation of TiN inclusions in steel was calculated thermodynamically. The results show that with the increase of the mass fraction of carbon in the steel, the concentration of nitrides and titanium needed to form TiN inclusions in the liquid phase before solidification gradually decrease, and at the late stage of solidification (the solid fraction is over 90%), The formation of TiN inclusions thermodynamic conditions. In the final solidification zone, the microstructure of steel is loosened to some extent due to insufficient filling of the molten steel, resulting in the coexistence of TiN inclusions and slab looseness. In order to control TiN inclusions in the steel with carbon content of 0.90% ~ 0.95%, it is necessary to further reduce the concentration of nitrogen and titanium in the liquid phase in the solidification front.