CSP薄板坯表面纵裂的影响因素

Influencing Factors of Longitudinal Surface Cracking of CSP Slab

研究了漏斗型结晶器形状、钢水化学成分和结晶器热流对薄板坯表面纵裂的影响。结果表明：漏斗型结晶器的开口度和漏斗曲线对纵裂的形成有重要影响，漏斗曲线的优化与铸坯出口厚度有关。CSP工艺冷却速度快，W（C）在0．07％～0．08％时，就开始发生包晶反应。因此，钢水碳含量应尽量远离包晶中心区域。钢中锰可改善钢的高温塑性，高W（Mn）／w（S）对减少纵裂有利。对CSP中碳钢，渣膜结晶率控制在40％，宽面热流控制在2．05MW／m^2左右时，纵裂发生率低。

The influencing factors of longitudinal surface cracking of CSP Slab such as funnel mold shape, chemical composition and mold heat flux were studied. The results show that the openness and shape of funnel mold are critical for formation of longitudinal cracking. The optimized funnel shape has relation to the slab thickness. As a result of high cooling rate of thin slab casting process, the peritectic reaction is occurred at 0. 07%-0. 08% ; therefore, the actual carbon content of steel should be far from this point. Adding manganese can improve the plasticity of steel, and high Mn/S is in favor of reducing the risk of longitudinal surface cracking. For medium carbon steel, the CSP should be operated with a mold power film of 40 % crystal ratio and a heat flux about 2.05 ×106 W/m^2 in favor of reducing the risk of longitudinal surface cracking,