窄带钢边部缺陷成因及对策

CAUSES AND COUNTERMEASURES FOREDGE DEFECTS OF NARROW STRIP STEEL

分析了窄带钢烂边的主要原因及对策。认为结晶器卷渣是窄带钢烂边的主要原因,非稳态浇注是造成结晶器卷渣的主要因素。形成非稳态的主要因素有:中间包液面波动过大;浸入式水口插入深度不足;浸入式水口不对中;浸入式水口管壁穿透;拉速过快;开浇及浇注结束时间短;保护渣性能不匹配等。其中任何一个因素出现问题都会造成严重的铸坯表面夹渣。结合企业实际情况,通过提高渣系碱度,规范换包操作,调整浸入式水口深度等措施控制结晶器卷渣后,窄带钢边部缺陷已基本消失。

The main causes and countermeasures of torn selvedge of narrow strip steel were analyzed. It is considered that slag entrapment in mold is the main cause for torn selvedge and unsteady casting is the main factor for slag entrapment. The main factors causing unsteady casting are as follows： excessive fluctuation of liquid level in tundish; insufficient depth of submerged nozzle; misalignment of submerged nozzle; penetration of pipe wall of submerged nozzle; excessive drawing speed; opening and ending time of pouring period; mismatch of mold flux properties. Any factors will cause serious slag inclusion on the billet. Combining with the actual situation of enterprise, the edge defect of narrow strip steel has basically disappeared after controlling the slag entrainment by improving the basicity of slag system, regulating the operation of ladle replacement and adjusting the depth of submerged nozzle.