PRODUCTION METHOD OF ROUND CAST BILLET WITH CONTINUOUS CASTING

PROBLEM TO BE SOLVED: To provide a producing method of a round cast billet with a continu ous casting, with which center segregation in the round cast billet can be re duced and center porosity can be eliminated and the desired roundness can be secured even in the case of varying the powering speed. SOLUTION: When the round cast billet is produced by applying rolling reduction to the continuously cast billet 4 having unsolidified part in the inner part and almost round shape in the cross section with one pair of unsolidified rolling reduction horizontal rolls 7, 7 and after forming the cross section to almost elliptic shape, the rolling reduction is applied with one pair of caliber vertical rolls 8, 8 for forming, the rolling reduction rate with one pair of the unsolidified rolling reduction horizontal rolls 7, 7, is decided based on the difference between the minor axis (d1) of the continuously cast billet 4 and the diameter (d2) of the round cast billet.