MANUFACTURE OF ROUND BILLET CASTING PIECE BY CONTINUOUS CASTING

PROBLEM TO BE SOLVED: To surely prevent a generation of casting failure in a round billet casting piece by defining a rolling condition for obtaining a given rolling draft when a pipe making round billet casting piece is manufactured using a so-called unsolidification rolling and an after-solidification forming method. SOLUTION: Under this manufacturing method for manufacturing a round billet cast piece, a casting piece 4 of almost circular shape cross section, having an unsolidified part inside, is pressurized with a pair of unsolidified pressurization horizontal rolls 7 for making the cross section almost an oval shape. Then, the cast piece is pressurized with a pair of hole-type molding vertical rolls 8. At this time, both of the unsolidified rolling horizontal roll 7 and the molding vertical roll 8 are driving rolls. Load of the unsolidified pressurization horizontal roll 7 is 500 ton or more, and its torque is 3 ton-m or more. Also, load of the molding vertical roll 8 is 100 ton or more and its torque is 25 ton-m or more.