开浇第一炉连铸坯夹杂物形成原因与控制措施

应用氮成分分析、Al烧损分析、硫印分析等分析方法，研究了转炉—LF—RH—连铸机生产宽厚板连铸坯开浇第一炉夹杂物形成原因及控制措施。结果表明，通过优化软吹工艺、增设中间包吹氩、减少开浇出苗时间、提高开浇操作水平、快速提拉速与减少浸入式水口插入深度，开浇第一炉连铸坯夹杂物含量比原来明显减少；同时，第一炉表面夹杂缺陷率大大降低，由优化前的42.1%降低为10.5%；铸坯中夹杂物在厚度方向上分布不均匀，铸坯厚度1/4处夹杂物较多，铸坯厚度中心有夹杂物聚集现象；在铸坯宽度方向的边部，钢中所含夹杂物较少；在铸坯宽度方向1/4处，钢中夹杂物显著增多；在铸坯中部，夹杂物明显增加。

Reasons and Control Measures of Inclusion in First Slab

The reasons and control measures of inclusion in first wide heavy slab produced by BOF-LF-RH-CCM were studied by means of ［N］ content analysis, aluminum burning loss analysis, Sulfur Print, etc. It is found that the inclusion contents of first slab obviously decreasing and the defect rate of surface inclusion was reduced from 42.1％ to 10.5％ through optimization of soft blowing process，Argon blowing in tundish , minimizing mould filling time, promoting operating level of start casting and accelerating casting speed fast．The distribution of inclusions was non-homogeneous along both thickness and wideness direction of slab. The inclusions assembled in 1/2 position and in 1/4 at board base thickness and width direction.