钙处理中间产物的形成及其对氧化铝夹杂的改性

Formation of intermediate products during calcium treatment and modification routes of alumina inclusions by intermediate products

通过观测钙处理前后夹杂物形貌和成分的变化,对钙处理效果、中间产物的形成及不同中间产物对氧化铝夹杂的改性路径进行了研究.结果表明,钙处理可将钢液中不规则固态夹杂改性为球形液态夹杂,并且各炉次夹杂物的改性程度不同.热力学分析表明,Als和S含量越高,氧化铝夹杂改性为液态的难度越大.钙处理后的短时间内,Ca S和CaO作为中间产物存在.通过建立中间产物生成的动力学模型,确定了生成不同中间产物的临界硫质量分数为11.1×10-6(钢液中溶解氧质量分数为4×10-6).由该模型结合结果分析,推断出不同中间产物对氧化铝的改性路径.

The calcium treatment effect,the intermediate product formation and the modification routes of alumina inclusions by different intermediate products after calcium treatment were investigated by observing the shape and composition of these inclusions. It is found that blocky or rectangular solid inclusions finally change into spherical liquid inclusions,but their modification degrees are different. According to thermodynamic analysis,the higher the Als and S concentration in molten steel,the more difficult the modification of alumina inclusions is. Ca S and CaO exist as intermediate products in a short time after calcium treatment. A kinetic model of intermediate product formation shows that the critical [S] mass fraction of the formation of different intermediate products is 11. 1 ×10^-6 with 4 × 10^-6 of dissolved oxygen. The modification routes of alumina inclusions by different intermediate products can be derived from the above model and experimental results.