IF钢非稳态浇铸铸坯洁净度分析

Research on Cleanness of IF Steel Slab Produced in Unsteady Casting Process

为研究非稳态浇铸对IF钢铸坯洁净的的影响,用钢中气体分析、成分分析、大型夹杂物分析方法对转炉—RH—连铸工艺生产的非稳态浇铸条件下的IF钢铸坯进行取样分析,主要分析头坯、尾坯和换水口坯。结果表明:头坯TO、N、C含量沿拉坯方向呈现上升趋势,Al、Ti正好相反;头坯TO质量分数平均比其他铸坯高0.001 5%以上,氮质量分数高达0.000 5%以上,碳含量超过判定标准;尾坯、换水口坯TO水平最高分别为正常坯水平的1.6倍和2.2倍,氮含量波动范围分别是正常坯水平的1.0～1.3倍和1.5～1.7倍,碳含量波动范围分别从正常坯水平的1.2～2.4倍和1.2～2.1倍,其他成分波动不大;大型夹杂物含量最高的是头坯34.37mg/(10kg),其次是尾坯29.67mg/(10kg),然后是换水口坯、大包停浇坯,而正常坯的大型夹杂物含量基本都在1.24mg/(10kg)以下。

In order to research the impact of unsteady casting process on IF steel slab,the cleanness of IF steel slab of unsteady casting conditions produced by the converter-RH-CC process was investigated by means of gas analysis,chemical composition analysis and big sample electrolysis of first slab,last slab and SEN-changing slab.The results show that TO,N,C content of the first slab rises along with the casting direction while Al and Ti content is just the opposite;average TO content of the whole first slab is 0.001 5% higher than other slabs,and N content 0.000 5% higher than other slabs,C content exceeds the criteria;the highest TO content of last slab and SEN-changing slab is 1.6 and 2.2 times average level of normal slabs,N content of last slab and SEN-changing slab fluctuation is 1.0-1.3 and 1.5-1.7 times average level of normal slabs,C content of last slab and SEN-changing slab fluctuation is 1.2-1.4 and 1.2-2.1 times average level of normal slabs,while other composition of last slab and SEN-changing slab has not very big fluctuation;content of large-sized inclusion of first slab is 34.37 mg/（10 kg） which is the highest,and then the last slab,and then the SEN-changing slab,ladle-casting-stop slab,content of large-sized inclusion of the normal slab is lower than 1.24 mg/（10 kg）.