ABSTRACT The character and cause of sliver defect on IF steel sheet surface are studied by means of SEM, unstable flow in mould could induce surface velocity and level fluctuations, leading to surface defects during continuous casting of steel. The nozzle clogging is a serious problem during the continuous casting of steel, due to its influence on the casting operations and products quality. In this study, the nail dipping method for measuring surface velocity and flow direction in molten steel were employed. The fluid flow in mould of whole casting sequence was investigated, especially during the nozzle clogging conditions. The results showed that when nozzle clogging occurred in the 7th heat, the flow velocities on R and L side of nozzle were 0.280 and 0.402 m/s, respectively. The surface defect ratio of hot-rolled and cold-rolled plates increases with the increase of heat flux deviation on both sides of the mould copper. The different clogging per cent on both sides of the nozzle will lead to asymmetry flow, the surface velocity is higher with the small clogging per cent side compared to that of relatively large per cent clogging side.

中文翻译：

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连铸过程中用浸钉法在模具中的流体流动和传热

摘要 利用扫描电镜研究了 IF 钢板表面长条缺陷的特征和成因，结晶器中不稳定的流动会引起表面速度和液位波动，导致钢连铸过程中出现表面缺陷。水口堵塞是钢连铸过程中的一个严重问题，它会影响铸造操作和产品质量。在本研究中，采用浸钉法测量钢水中的表面速度和流动方向。研究了整个浇注顺序模具中的流体流动，特别是在喷嘴堵塞条件下。结果表明，在第7炉发生喷嘴堵塞时，喷嘴R侧和L侧的流速分别为0.280和0.402 m/s。热轧板和冷轧板的表面缺陷率随着模具铜两侧热流偏差的增加而增加。喷嘴两侧不同的堵塞百分比会导致不对称流动，与较大百分比堵塞侧相比，小堵塞百分比侧的表面速度更高。