超纯铁素体不锈钢中TiN析出的动力学分析

Kinetics of TiN precipitation in ultra-clean ferritic stainless steel

采用动力学的方法研究超纯铁素体不锈钢凝固过程中Ti、N的偏析及冷却速率对TiN夹杂析出的影响。结果表明,超纯铁素体不锈钢凝固过程中,Ti的富集程度稍低于N;凝固末期残余液相中[Ti]和[N]的浓度分别提高至其初始浓度的2.5倍和3.2倍;随着钢液的逐渐凝固,析出的TiN颗粒尺寸增大;随着冷却速率的增大,析出的TiN颗粒尺寸减小,但析出时间几乎不受影响,冷却速率分别为10、20、30K/s时,TiN颗粒尺寸分别为7.1、4.8、3.9μm;其他条件相同时,随着钢中初始Ti含量或N含量的减少,凝固析出的TiN颗粒尺寸减小且析出时间推迟;相比Ti含量对TiN夹杂尺寸的影响,N含量的影响更为显著。

The effect of segregation and cooling rates of Ti and N on the precipitation of TiN inclusions in the process of solidification of ultra-clean ferritic stainless steel was investigated by kinetic means. The results show that, in solidification of ultra-clean ferritic stainless steel, the segregation degree of Ti is less than that of N and at the end of solidification, the contents of [Ti] and IN] in residual liquid increase to 2.5 and 3.2 times, respectively. Along with solidification of liquid steel, the size of TiN precipitated is increasing, and when the R~~10 K/s, 20 K/s, 30 K/s, the size of TiN is 7.1, 4.8, and 3.9 t^m, respectively and the cooling rate almost has no effect on the precipitation time. When other conditions are the same, with the decrease in [%Ti] or [%N], the size of TiN decreases and precipitation appears later. Compared with Ti, the content of [N] has greater effect on the size of TiN.