连铸板坯夹渣产生的原因及控制措施

Formation Causes and Control Measures of Inclusive Slag in Continuous Casting Slab

表面夹渣是连铸板坯常见的表面缺陷,直接影响成品的表面质量。分析了低碳铝镇静钢夹渣类缺陷的连铸工序因素,浸入式水口插入深度140mm时的夹渣缺陷率远低于插入深度120mm时的夹渣缺陷率,非稳态浇注时夹渣缺陷率远高于稳态浇注时。通过中间包流场和拉速升降基准优化、中间包钢水量控制等措施,因夹渣导致的钢卷改判率由1.2%下降至0.5%以下。

Surface inclusive slag is the common surface defect of continuous casting slab,which affects the surface quality of finish product directly.The paper analyses the continuous casting process factors of inclusive slag type defect for low carbon Al-killed steel,the results show that for submerged entry nozzle,inclusive slag defect rate at 140 mm insert depth is much lower than that at 120 mm insert depth,the inclusive slag defect rate at non-steady state casting is much higher than that at steady state casting.By means of measures of optimizing tundish flow field and rise and drop datum of withdrawal speed,controlling tundish molten steel volume,the downgrading rate of steel coil due to inclusive slag defect is reduced from 1.2%to 0.5%and below.