PURPOSE: To form a steel strip with an irregular shaped section whose thick parts on the center side with plural the same sectional shapes, and a thick part and a thin part of edge parts positioned on both ends, are made continuous through parts of difference in level respectively, so that all the gradient angles of the parts of the difference in level of the thick part on the center side become the same.
CONSTITUTION: When manufacturing by passing through a strip metal to be rolled with a width wider than or the same as that of an irregular shaped section steel strip to be manufactured between a work roll 5 with a projecting line part, on which plural projecting line parts 5b forming a thin part 3 in the circumferential direction of a barrel part 5a, are formed, and a flat work roll 6, the work roll 5 with a projecting line part, whose projecting line parts 5b with the same sectional shape, are all formed in the circumferential direction of a barrel part 5a as the work roll 5 with a projecting line part and as plural projecting line parts 5b forming the thin part 3, is used.
SAKAKI MASAHITO
HARA KENJI
NAKAMOTO KAZUNARI
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