Abstract: During the 150 mm×150 mm billet continuous casting practice，static soft reduction at the solidification end of the high carbon steel billet had been implemented by adjusting the current pulling straightening roller pressure，drawing speed and the secondary cooling. The results showed that certain reduction formed by appropriate pressure matching with the appropriate casting speed could make the pulling straightening roller pressure be passed to the more suitable soft reduction zone. After the process optimization, the low power grading results indicate that the highest shrinkage defects rating decreased from grade 3.0 to grade 2.0, the highest center porosity rating decreased from grade 2.5 to grade 1.5, and the highest solidification center carbon segregation index decreased from 1.35 to 1.08. The whole shrinkage size and the center porosity areas had been improved to some extent under the static soft reduction formed by the pulling straightening roller.

Key words: high carbon steel, billet, pulling straightening roller, static soft reduction, center segregation