Numerical Simulation of Continuous Casting Round Blooms with Different Solidification End Reduction Strategies

To solve the problem of application of the reduction process in the continuous casting of round blooms, double-roll, three-roll and four-roll staggered extrusion schemes were proposed, and three series of three-dimensional thermal-mechanical coupling models were established to analyze the advantages and disadvantages of each reduction scheme. It was found that the double-roll scheme transfers the reduction deformation to the center of the round bloom and closes the internal porosity more efficiently. For each squeeze, the double-roll extrusion scheme can easily cause lateral deformation, which may improve the equivalent strain value to the inside of the round bloom more efficiently, and there is a concentration phenomenon in the center after several sets of reductions. The three-roll scheme and the four-roll scheme have difficulty causing lateral extension, and the reduction is basically consumed by the harder shell deformation, which causes much more longitudinal stretching deformation of the round bloom. With an increase in the solid fraction (f(s)), the round bloom will accept a larger reduction under the limit of the initiation of internal cracks. At positions with the same f(s), the tensile strain of the crack risk area caused by the double-roll scheme is larger than that of others, which means that the limitation of the maximum reduction amount of the double-roll scheme is stricter than that of the other two schemes.