Abstract: In order to explore the formation process of the abnormal oscillation marks for the high carbon steel in this paper, the surface and longitudinal section morphology of the abnormal oscillation marks was investigated by optical microscope analysis. The results indicated that insufficient lubrication and large frictional resistance between the billet and the mold were the main reasons to make the oscillation mark bended, protruding and even the formation of double skin. With the oscillation frequency and amplitude set as 180 strike/min and 4.2－4.5 mm, the viscosity and melting temperature of mold powder set as 0.18 Pa·s and 1 030 ℃, the powder consumption was increased from 0.18kg/t to 0.31 kg/t. At last, the surface quality of the billet was improved obviously, the oscillation marks had returned to normal, and the rejection ratio decreased from 3 %－4 % to less than 1 %.

Key words: high carbon steel, continuous casting, billet, oscillation parameters, mold powder