*2.1. Materials*

Continuous casting experiments were carried out at Hebei Iron and Steel Group Co., Ltd. in Shijiazhuang, China. Samples of flux films (see Figure 1) were taken from the meniscus region (see Figure 2).

**Figure 1.** Samples of solidified flux films.

**Figure 2.** Position diagram of flux films in mold.

Combined with the surface quality of the slab, four typical samples of flux films were selected. Sample No. 1 represents flux films with normal slab quality for peritectic steel A, and sample No. 2 represents flux films with longitudinal cracks on the surface of the slab for peritectic steel A. It was the same with sample No. 3 and sample No. 4 for peritectic steel B. Some parameters of the typical flux films and the corresponding slab quality are listed in Table 1. Chemical compositions and physical properties of mold fluxes for peritectic steels A and B are listed in Tables 2 and 3.


**Table 1.** Parameters of mold flux films for peritectic steels.

**Table 2.** Chemical compositions of mold fluxes (wt%).


**Table 3.** Physical properties of mold fluxes.

