in subsequent rolling operations. Depending on the grade of steel and product applications, either of two practices is employed: (1) silicon deoxidation with a small addition of aluminum for coarse grain steels; (2) aluminum deoxidation for fine grained steel. Silicon-killed steels are easier to cast than aluminum killed steels because deposits of alumina in the tundish nozzle, which cause nozzle blockage, are avoided. For high-quality products, it is ing mon practice to employ a ladle refining practice prior to casting. 连铸连铸的发展二战之后,连铸发展非常迅速_今天钢铁生产者普遍相信连铸至少和模铸一样在经济上是合理的, 并且能与大部分高质量钢的生产系列相匹配。这项技术不断开发的目的在于改善钢的性能, 这促使生产特殊高级钢时企业对其生产工艺过程不断进行调整。使用连铸系统的理由有: (l )和初轧机组(小型车间)相比,降低投资费用; (2 )和传统的铸锭相比,提高 10% 的生产能力; (3) 在整个铸坯长度上钢的成分较均匀; 中心质量比较好, 尤其是板坯; 高的内表面质量, 比其他需要昂贵的清理表而的工序节省; (4) 高度的自动化; (5) 益于保护环境;