Abstract: In view of the deep oscilation mark, longitudinal crack and transverse brittle fracture of the surface of QP980 continuous casting slab for high strength automobile, by measuring the high temperature plasticity and thermal conductivity of QP980 steel, it is clear that the serious peritectic reaction is the cause of the quality defect. By optimizing the mold flux, secondary cooling and hot charging process, the quality defects of the slab are eliminated and the quality of hot rolled coils is good.

Key words: QP980steel, crack, second cooling, hot charging