IF钢连铸坯表层夹杂分布特征的试验

 夹杂物是影响IF钢表面质量的重要因素。对IF钢连铸坯表面进行在线火焰自动清理时，确定不同状态连铸坯的最佳清理深度非常重要。针对IF钢浇次第2块铸坯、稳态铸坯及头罐与第2罐的交接坯，在每块铸坯的内弧和外弧面分别沿宽度方向等距离共取28个分析试样，每个分析试样尺寸为29 mm×21 mm×30 mm，研究不同清理深度下夹杂物的形态、数量、最大尺寸的变化情况。结果表明，随着清理量的不断增加，浇次第2块铸坯20～50 μm夹杂物的数量不断减少，大于50 μm夹杂物的数量略有增加，稳态坯和交接坯大于20 μm夹杂物的数量略有降低。在铸坯表面未清理时，3块铸坯表面最大夹杂物尺寸分别为500、200、200 μm，如果考虑影响钢板表面质量夹杂物的临界尺寸为100 μm，则浇次第2块铸坯清理深度应为4～5 mm，稳态坯和交接坯的清理深度应为2 mm。

Experiment on distribution characteristics of surface inclusions in IF steel continuous casting billet

Inclusions are important factors that affect the surface quality of IF steel. It is significant to determine the optimum cleaning depth of continuous casting billet in different states when the IF steel continuous casting slab is cleaned on-line flame automatically. The second pouring piece of slab，the steady casting billet and the transfer billet between head and second cans of IF steel was dealed with. A total of 28 analytical samples are equidistance divided along with the width direction of the inner and outer surfaces of the each casting，and the size of each specimen is 29 mm×21 mm×30 mm. The changes of morphology，quantity and maximum size of inclusions under different cleaning depth are studied. The results show that the number of inclusions which is 20-50 μm in the second piece of slab is decreased with the increase of the cleaning capacity，the number of inclusions which is larger than 50 μm is slightly increased，and the number of inclusions which is larger than 20 μm in the steady state and the transfer billet is slightly reduced. When the surface of the slab is not cleaned，the maximum inclusions on the surface of the three slabs are 500，200 and 200 μm respectively. If the critical dimension of the inclusions affecting the surface quality of the steel plate is 100 μm，the second slab cleaning depth should be 4-5 mm，the steady casting billet and the transfer billet should be 2 mm.