Abstract: Hot loading and hot delivery of con-casting billets can significantly reduce rolling costs, save energy, reduce carbon emissions, and improve the economic benefits of enterprises. Good billet quality is the foundation of hot loading and hot delivery, and dent defects in billet are one of the important factors affecting the surface quality of the billet. The influence of mold parameters on billet dents was discussed in the paper. According to the numerical simulation and the shrinkage characteristics of the billet, the mold taper was reasonably designed from the original single-taper to the three-taper, so that the mold taper coincides with the cooling and shrinkage of the liquid steel in the mold, the cooling of the corners and central parts were more uniform, and the defects of dent reduced significantly in billets. The coating and slow cooling strip were added to the mold, weakening the corner cooling, making the cooling of the billet uniform, reducing the occurrence of dents, and improving the hot delivery rate and yield of the billet. After mold parameters optimization, the pass rate for dent in CrMo steel billet increased from 73.73% to 94.80%, the average width of the dent reduced from 45 mm to 15 mm, and the depth reduced from 5 mm to 2 mm.

Key words: casting billet, defect of dent, mold, taper