| 摘要 |
PURPOSE:To produce a lip channel efficiently by subjecting a blank steel ingot to rough rolling, intermediate rolling and finish rolling, then forming curved parts in the part corresponding to a web and bending the curved parts at a right angle. CONSTITUTION:A heated blank ingot is rolled with roughing mills to a thick walled blank shape steel of a prescribed shape. Thence, this is subjected repeatedly to reduction rolling with an intermediate rolling mill group to a thin walled blank shape steel of a prescribed shape. Further, it is conducted to a finishing mill group, where it is formed to a broad channel 18 by one pass rolling with horizontal rolls 16, 16' alone of UF mills, after which curved parts of a curving angle theta1 are provided at two points of a prescrived equal distance on the right and left from the center of the part corresponding to a web by means of the horizontal rolls 19, 19' of EF mills, and these parts are bent in such a way that flanges oppose to each other toward the inner side. Next, the angle theta1 is formed approximately to a right angle theta2 by the press-rolling with vertical rolls 17, 17' of UF mill. Then, the press-rolling in the vertical direction by means of the horizontal rolls 16, 16' alone of the UF mills is performed, whereby the steel is finished and shaped to a lip channel. |
