Abstract: The reason of sliver defect on the surface of hot-rolled SPHC strip was investigated. The results showed that mold powder entrapment caused by the clogging of submerged entry nozzle was the predominant reason in the process of continuous casting. Calcium treatment thermodynamics and tundish flux chemistry were optimized based on the thermodynamic calculation and industrial experiments. After the optimized processing parameters were used, the clogging issue of submerged entry nozzle was resolved effectively, mold level fluctuation could be steadily controlled at less than ±3 mm, and surface sliver defect of hot-rolled SPHC strip was significantly reduced.

Key words: SPHC, sliver defect, calcium treatment, tundish flux