不同浇铸阶段低碳钢连铸板坯洁净度研究

通过运用氧氮分析仪、金相分析、大样电解分析、扫描电镜及能谱分析等分析手段，研究了LD-氩站-CC 生产的低碳钢1个浇次不同浇铸阶段铸坯（头坯、正常坯和尾坯）的洁净度。通过对不同浇铸阶段铸坯的 w T［O］ 和 w ［N］ 对比分析可知，开浇时钢水的二次氧化比较严重，浇铸末期钢水的二次氧化较轻;正常坯的显微夹杂物数量为 7.96个/mm 2 ，头坯和尾坯的显微夹杂物数量相对正常坯分别升高了约98%和33%，显微夹杂物主要为:Al 2 O 3 、 Al 2 O 3 -（Mn，Fe）S。正常坯中大型夹杂物数量最少，为1.91 mg/（10 kg）;头坯中大型夹杂物数量最高，为8.24 mg/ （10kg），尾坯中大型夹杂物数量为2.72 mg/（10 kg），头、尾坯中大型夹杂物多伴有Na、K，说明开浇和浇铸末期结 晶器卷渣严重;尾坯中含有较多的MgO-Al 2 O 3 和Al 2 O 3 -CaO-SiO 2 -MgO夹杂物，表明浇铸末期发生了中间包漩涡 卷渣。

Studying on Cleanliness of Low Carbon Steel Slabs Produced in Different Casting Stages

By means of Oxygen and Nitrogen Analyzer,Metallographic Examination,SLIME,SEM,EDS,etc.,the cleanliness of low carbon steel slabs(first slab,normal slab and final slab) produced in different casting stages by LD-argon-blowing station-CC.Through the comparative analysis of TO] and N] of different casting stages’ slabs,the reoxidation of liquid steel was very serious in casting starting.However,it was not in casting ending.In comparison with the micro-inclusions’ quantity of normal slab(7.96 per square millimeter),the first slab and the final slab respectively increased by 98% and 33%.The component of micro-inclusions were mainly Al2O3 and Al2O3-(Mn,Fe)S.The quantity of large-inclusions was minimal,which was 1.91 mg/(10 kg) in normal slab.While the first slab contained the maximal quantity,it was 8.24 mg/(10 kg).The quantity of large-inclusions was 2.72 kg/(10 kg) in the end slab.Most of large-inclusions contained K or Na elements in the first slab and final slab,which might relate to serious slag entrapment in the mould when the casting starting and ending.The quantity of MgO-Al2O3 inclusions and Al2O3-CaO-SiO2-MgO inclusions was very high in the end slab,which suggested the entrapment in the tundish happened in the casting ending.