稳态浇铸下低碳铝硅镇静钢卷渣产生的原因和控制对策

The causes and countermeasures of slag entrapment in low carbon Al-Si killed steel under steady casting condition

随着连铸产能的提升,板坯的液面和拉速波动合格率为100%,这种稳态浇铸前提下,生产某低碳铝硅镇静钢发生批量卷渣缺陷,卷渣率为19.6%(将其卷渣指数设定为100%)。分析发现工艺上钢水过热度、拉速和保护渣成分对卷渣直接产生作用,生产操作上浸入式水口浸入深度也对卷渣产生影响。通过收窄过热度和拉速范围、优化浸入式水口浸入深度和调整保护渣成分这4个手段,该钢种的卷渣指数由100%下降到14.7%,配合采用含Li2O高黏度保护渣的优化效果最好,卷渣指数仅为13.3%。

With the improvement of continuous casting capacity, the qualified rate of liquid level and velocity fluctuation of slab is 100 %. Under the premise of steady casting, the mass slag entrapment defect occurred in the production of a low-carbon aluminum silicon killed steel, and the slag entrapment rate was 19.6 %(the slag entrapment index was set as 100 %). It was found that the superheat of molten steel, the velocity and the composition of protective slag had direct effects on the slag rolling, and the immersion depth of submerged nozzle also had an effect on the slag entrapment. By means of narrowing the superheat and velocity range, optimizing the immersion depth of the nozzle and adjusting the composition of the slag powder, the slag entrapment index of this kind of steel was reduced from 100 % to 14.7 %, and the best optimization effect was achieved by using Li2O high-viscosity slag powder, with the slag entrapment index was only 13.3 %.