Abstract: To determine the soft reduction zone in 82B steel continuouscasting bloom with section size of 180 mm×240 mm, a mathematical heat transfer model was developed based on the finite element commercial software ProCAST. The adequacy of the model was compared with pinshooting results and surface temperature measurement. The results showed that the grade of center porosity equals to 1.0 was increased from 55 % to 77 %and the percentage of shrinkage cavity less than level 0.5 was increased from 45 % to 90 % with the soft reduction. Besides, soft reduction process was used successfully for suppressing Vsegregation. The mean center carbon segregation index was reduced from 1.17 to 1.07 and the maximum center carbon segregation index decreases from 1.27to 1.15.

Key words: soft reduction, high carbon steel rectangular bloom, center segregation, center porosity, shrinkage cavity