IF钢铸坯皮下小气泡分布

Distribution of small bubbles at IF continuous casting slab subsurface

通过铸坯取样分析研究了板坯结晶器内拉速和电磁制动与小气泡分布之间的关系，探讨了拉速以及电磁制动对IF钢铸坯皮下气泡大小、数量和分布的影响规律．实验结果表明：铸坯皮下气泡直径小于0．1mm的气泡占总数的57％，0．1—0．5mm之间的占42．5％，大于0．5mm占0．5％，并且随着皮下距离的增加，被捕捉的气泡尺寸越来越小，而气泡数量边部比1／4处要多50％左右，1／4位置最少；拉速提高会导致气泡尺寸变小，在1／4及边部，气泡聚集位置由皮下9mm变为12mm附近，但是低拉速和高拉速均在皮下3mm位置处有气泡聚集；电磁制动下，铸坯中心处气泡尺寸变大，1／4及边部位置气泡尺寸变小，且会使气泡数量总体降低，主要表现在聚集位置处的气泡数量明显减少．

The distribution behavior of bubbles in consideration of casting speed and electromagnetic braking in a slab continuous casting mold was investigated by the method of sampling statistics. The effects of electromagnetic braking and casting speed on the size, number and distribution of small bubbles were analyzed in detail. Experimental results show that bubbles with the diameter less than 0.1 mm account for 57%, 0.1-0.5 mm for 42.5%, and bigger than 0.5 mm for 0.5%. The deeper the subcutaneous distance is, the smaller the bubble size is. The number of bubbles in the narrow side is 50% more than that in the 1/4 position, and the number of bubbles in the 1/4 position is the least. With increasing casting speed, the size of bubbles decreases and the position of clusters moves from 9 to 12 mm in the slab subsurface at the 1/4 position and the narrow side, but bubbles gather at 3 mm of subsurface at the low and high casting speeds. When electromagnetic braking is applied, the size of bubbles becomes big in the center, but small in the 1/4 position and the narrow side, and the number of bubbles overall declines, significantly the number of cluster bubbles.