连铸保护渣性能对中板表面夹杂缺陷的影响

INFLUENCE OF CASTING POWDER TO SURFACE INCLUSIONS OF MEDIUM PLATE

针对柳钢中板表面夹杂物缺陷的特点,分析了夹杂物的来源和保护渣性能、形态对夹杂物的影响。柳钢中板表面夹杂缺陷,由钢中溶解铝被二次氧化而产生的Al_2O_3,在水口中凝结长大,被铜流冲刷进入结晶器,以及水口耐火材料被冲入结晶器内被凝固壳捕捉而产生的。保护渣的绝热性能对夹杂物能否避开凝固壳的捕捉而上浮到渣金界面有重要影响。其绝热性能受其熔化性能及其形态影响。

Against the characteristics of surface inclusions of medium plate, the resources of inclusions, the influence of the performances and shape of casting powder to inclusions were analyzed. The surface inclusions of medium plate were caused by two factors that Al2O3, which was generated by reoxidation of dissolved aluminum in steel, was condensed and grew in the nozzle and flushed into mould by steel flow; and the refractory of nozzle was flushed into mould and caught by solidified shell. The insulating ability of casting powder has the big influence that whether the inclusions can avoid the catch-up of solidified shell and then float up the slag-metal interface or not. And furthermore, the insulating ability of casting powder was influenced by its melting ability and shape.