高铝钢中钙处理对非金属夹杂物特征的影响

Effect of calcium treatment on characteristics of non-metallic inclusions in steel containing high Al

为了研究高铝钢中钙处理量与夹杂物特征的关系,通过SEM-EDS检测了钢中夹杂物形貌和成分,并结合图像处理软件、体视学等方法统计了夹杂物三维尺寸分布、夹杂物间距和夹杂物分布等参数。结果表明,钙处理高铝钢中夹杂物主要有Al2O3-CaO-(CaS)复合夹杂物和AlN等两类夹杂物。高铝钢中钙质量分数由0.000 4%增加到0.002 4%时,夹杂物的平均尺寸由2.5减小到1.8μm,夹杂物数量是原来的2倍,夹杂物平均间距由95减小到72μm。通过FactSage热力学计算讨论了冷却过程中夹杂物成分的演变过程,计算结果与试验结果相符。最后根据夹杂物形核计算讨论了夹杂物特征与形核尺寸的关系以及高铝钢中夹杂物分布的影响因素。

The morphology and the composition of inclusion were observed by SEM-EDS.The particle size distribution in three-dimensional,the inter-surface distance and the distribution of inclusions were analyzed by an image software based on the stereology method.The results indicate that there were mainly Al2 O3-CaO-(CaS)complex inclusions and AlN inclusions in the high Al steel after the calcium treatment.As the mass percent of Ca increasing from 0.0004%to 0.0024%,the average size of inclusions decreased from 2.5 to 1.8μm,the number density of inclusions increased by about one time,and the average inter-surface of inclusions decreased from 95 to 72μm.Besides,the transformation process of inclusion composition during the cooling process was studied by FactSage thermodynamic calculation and the calculated results were in agreement with the experimental results.The relationship between the nucleus size and the characteristics was analyzed based on the calculation of inclusion nucleation.The factors affecting the inclusion distribution in the steel containing high Al were also discussed.