| 摘要 |
PURPOSE:To stabilize product shape and improve rolling work efficiency by roughing a slab to a channel sectional shape then subjecting the parts corresponding to a web and flanges to forging screw-down thence heavily pressing the same to thicken and reshape the corner parts. CONSTITUTION:A slab or the like is roughed by a caliber type roughing mill 1 to an intermediate rolled material a1 having a web-corresponding part b1, both- flange-corresponding parts C1 and inside corner bulged parts e1. Next, it is subjected to forging screw-down with a univeral rolling mills, after which it is subjected to reverse rolling involving forging screw-down of the chamfered corner parts d1 by means of caliber die edger mills. By this reverse rolling, the intermediate rolled material a1 is formed to a finish rolled material a2 of a channel section having chamfered corner parts d2 at the outside corners and bulged parts e2 at the inside corners. Thence, the bulged parts e2 are subjected to heavy screw-down by caliber finishing rolls, to fill the excess metal of said bulged parts b2 into the unthickened parts formed by the chamfered corner parts d2; at the same time, the web-corresponding part (b2) and the flange-corresponding parts c2 are screwed down, whereby the material is finished to a product of a parallel flange channel. |
