钢液成分对钙处理夹杂物改性效果的影响

Influence of molten steel composition on modification effect of inclusions during calcium treatment

钙处理是解决铝镇静钢水口结瘤问题的常用手段。通过热力学计算和工业试验研究了钢液成分对钙处理夹杂物改性效果的影响。FactSage热力学计算表明,在一定温度下,钙处理夹杂物改性效果与钢液中氧、硫相对含量密切相关。氧含量一定时,一定范围内的硫含量越高,平衡时夹杂物能达到的最大液相率越小,喂钙量的工艺窗口越窄;硫含量一定时,一定范围内的氧含量越高,平衡时夹杂物能达到的最大液相率越大。工业试验中,对中间包取样,低氧高硫炉次钢中典型夹杂物主要相是高熔点镁铝尖晶石和CaS复合夹杂物,高氧低硫炉次钢中典型夹杂物主要相是低熔点钙铝酸盐。工业试验分析结果与理论计算的趋势一致。

Calcium treatment is a common method to solve the problem of nozzle clogging in aluminum killed steel production. The influence of molten steel composition on modification effect of inclusions during calcium treatment was studied by industrial experiments and theoretical calculation. The thermodynamic calculation of FactSage showed that the modification of inclusions during calcium treatment was closely related to the relative content of oxygen and sulfur in the molten steel at a certain temperature. When the oxygen content was fixed, within a certain range, the higher the sulfur content, the smaller the maximum liquid phase ratio of inclusions at equilibrium, and the narrower the process window of feeding calcium. While, when the sulfur content was fixed, the higher the oxygen content within a certain range, the larger the maximum liquid phase ratio of inclusions at equilibrium. In the industrial test, the typical inclusions in steel with low oxygen content and high sulfur content were magnesium aluminum spinel and CaS composite inclusions with high melting point. However, the typical inclusions in steel with relatively high oxygen content and low sulfur content were mainly calc-aluminate with low melting point. The results of industrial experimental analysis were consistent with the trend of theoretical calculation.