PREFORMING METHOD OF BLOOM

摘要

PURPOSE:To prevent the generation of fish tail in blooming by pressing the specific range in the end part of a bloom prior to blooming of the bloom thereby forming a compressed part. CONSTITUTION:A compressed part Bc is formed in an arc shape in one end part in the longitudinal direction of a bloom B or tranversely in both end parts thereof prior to blooming with a rolling roll 41. The part Bc is formed by pressing the bloom B under prescribed pressure P in the transverse direction thereof with a pressing tool 5 having a head 51 formed with an arc-shaped working face 511 of >=400mm. radius of curvature. The fish tail generated when the bloom B is bloomed is offset by the preforming owing to the overhanging effect of the extreme end face that arise when the part Bc is formed, whereby the generation of the fish tail is decreased considerably.