LAUSR

The continuous casting is the predominant technique for the solidification of molten steel to form billet, slab, or bloom. In this process, the liquid steel is poured in the mould, which is cooled by water so that to form a shell of sufficient thickness. Below the mould, the partially solidified strand enters the secondary cooling zone, where the solidifying strand is further cooled by the water sprays. After the secondary cooling zone, the strand is cooled by air naturally in the radiation zone until fully solidification. Then the solidified strand is straightened, cut, and transported for further processing. As shown in Fig. 1. Continuous casting is also a continuous heat extraction process. The defects of strand, especially the internal cracks and shrinkage cavity, are closely related with heat transfer and the distribution of thermal stress, which is mainly affected by the inappropriate casting operation and secondary cooling water distribution.1–5) In order to produce the strand as little defect as possible, many scholars have researched on the formation mechanism of internal cracks and other defects, which offers theoretical foundation for preventing the occurrence of defects and optimizing the secondary cooling water distribution for improving the strand quality.6–8) The accurate control of the secondary cooling water distribution can obviously improve the quality of the Optimization of Secondary Cooling Water Distribution for Improving the Billet Quality for a Small Caster